release: bump 0.6.5 -> 0.6.6 (#203 )

Release 0.6.6 — ships the B11 Pivots & S/R indicators (467 total) plus the bit-exact batch fast paths and benchmark refresh from #202. Version-string bump only: Cargo workspace + wickra-core dep, Python pyproject, Node package.json (+6 platform packages), both package-lock files, Cargo.lock, and CHANGELOG.
perf: bit-exact batch fast paths + streaming-first benchmark docs (#202 )
2026-06-08 00:21:34 +02:00 · 2026-06-08 00:17:58 +02:00 · 2026-06-08 00:13:42 +02:00 · 2026-06-07 04:34:32 +02:00 · 2026-06-07 04:25:16 +02:00 · 2026-06-07 03:20:19 +02:00
137 changed files with 38440 additions and 442 deletions
@@ -5,5 +5,7 @@
 maturin
 numpy
 pandas
+TA-Lib
+tulipy
 talipp
 finta
@@ -1,5 +1,13 @@
 # This file was autogenerated by uv via the following command:
 #    ./scripts/update-lockfiles.sh
+build==1.5.0 \
+    --hash=sha256:13f3eecb844759ab66efec90ca17639bbf14dc06cb2fdf37a9010322d9c50a6f \
+    --hash=sha256:302c22c3ba2a0fd5f3911918651341ebb3896176cbdec15bd421f80b1afc7647
+    # via ta-lib
+colorama==0.4.6 \
+    --hash=sha256:08695f5cb7ed6e0531a20572697297273c47b8cae5a63ffc6d6ed5c201be6e44 \
+    --hash=sha256:4f1d9991f5acc0ca119f9d443620b77f9d6b33703e51011c16baf57afb285fc6
+    # via build
 finta==1.3 \
    --hash=sha256:b94b94df311c18bf5402eb2fe8fd2db5e1bdaff08baf58a7367d05c7abdd10d3 \
    --hash=sha256:f2fa0673748f4be8f57e57cf6d5c00a4d44bc6071ea69dbb9a1d329d045cbba2
@@ -97,6 +105,12 @@ numpy==2.4.6 \
    #   -r .github/requirements/bench.in
    #   finta
    #   pandas
+    #   ta-lib
+    #   tulipy
+packaging==26.2 \
+    --hash=sha256:5fc45236b9446107ff2415ce77c807cee2862cb6fac22b8a73826d0693b0980e \
+    --hash=sha256:ff452ff5a3e828ce110190feff1178bb1f2ea2281fa2075aadb987c2fb221661
+    # via build
 pandas==3.0.3 \
    --hash=sha256:0383c72c75cdcca61a9e116e611143902dbfd08bff356829c2f6d1cf40a9ca8c \
    --hash=sha256:05f1f1752b8533ea03f7f39a9c15b1a058d067bb48f4748948e7a8691e0510f2 \
@@ -149,6 +163,10 @@ pandas==3.0.3 \
    # via
    #   -r .github/requirements/bench.in
    #   finta
+pyproject-hooks==1.2.0 \
+    --hash=sha256:1e859bd5c40fae9448642dd871adf459e5e2084186e8d2c2a79a824c970da1f8 \
+    --hash=sha256:9e5c6bfa8dcc30091c74b0cf803c81fdd29d94f01992a7707bc97babb1141913
+    # via build
 python-dateutil==2.9.0.post0 \
    --hash=sha256:37dd54208da7e1cd875388217d5e00ebd4179249f90fb72437e91a35459a0ad3 \
    --hash=sha256:a8b2bc7bffae282281c8140a97d3aa9c14da0b136dfe83f850eea9a5f7470427
@@ -157,10 +175,72 @@ six==1.17.0 \
    --hash=sha256:4721f391ed90541fddacab5acf947aa0d3dc7d27b2e1e8eda2be8970586c3274 \
    --hash=sha256:ff70335d468e7eb6ec65b95b99d3a2836546063f63acc5171de367e834932a81
    # via python-dateutil
+ta-lib==0.6.8 \
+    --hash=sha256:02388054c059945e5f02625f5075bac20a1803573cb43e7d096091027511961f \
+    --hash=sha256:094677b279a59c3f01c3aca8a889fda3523fd641a3805f69a2d642121b72e55e \
+    --hash=sha256:0a08a29690a922ba92a6cf42902a8a93c6fbda4cfed62c3c5b0471560ef60135 \
+    --hash=sha256:0ccd478ff5735831bf2a61d653466bfda8afadc26ad58ca6b1edb9e7521cc674 \
+    --hash=sha256:0e371d14b49e70caa973a234c8823341dd446f5c5d7acc826868bb42b272bdc0 \
+    --hash=sha256:11a373c9308eae3bac2d56d37017f9ab63968cc074a8b95be879aae3d13133aa \
+    --hash=sha256:128ec92e6a0e9ff7a38edef80e3b74f15bb2ed1c531d5d3252c8dca22677651b \
+    --hash=sha256:1fb4028437201e19014e4e374272b739867c8a3eb655da46675ef4c2ff14b616 \
+    --hash=sha256:282e49c766b5952dd8796f77d7ed3ae412cdd88e31f845b1fbbb86ac6cb7bebf \
+    --hash=sha256:2b369cabb48485fbf444beb3f5a878075367b99c2c86db2f796afeabebc749e0 \
+    --hash=sha256:2bf714333788bf5175f2512b86d2ed129e89ae6f6c2923e8a297a1e3395e13b5 \
+    --hash=sha256:30de46b55873b51be945a09edf486afcc190dc47eff9fb5d2b12c9f7e3d743da \
+    --hash=sha256:34e3b12407ddf99f6627435aa8a165f094339bb7dc33de92e1d7472e9f237304 \
+    --hash=sha256:36b2a516fce57309840f5ef3fa2fd0c4449293fc72536a0400d2e1e26b414da8 \
+    --hash=sha256:3a9195299df9d7d2a6e9d16bebd6b706b0ea99e4b871864c4b034c2577e21a77 \
+    --hash=sha256:3c32fc0f546ceecc47dd45f33d72ab4a1e341b80d9081c2d77b100add5d49104 \
+    --hash=sha256:3d7333e907bff3e3997e54f89733ffa8d619842a3e1cd962bca34bdc11944c28 \
+    --hash=sha256:4795e93d130c9b7fb661f0cead49752ae6a980437df74b99d5918026c212443e \
+    --hash=sha256:490e19a45cd3cdd6dfe6b46019f7ffe1103500750b41b51996a870e7c1c5f066 \
+    --hash=sha256:4aa0fe08383f3e5fc7d2f8cf9b42ac778f4d53fd75bcd2799a858225954eab89 \
+    --hash=sha256:559326d8f3d904cd4aa61f6a392d5626f35eec6a9f6cc83bcddb0abf88c40516 \
+    --hash=sha256:5929c83bd8cb7572d1c17ffdbf0eac235bf3c4d53cde1950cf89d944eaf97525 \
+    --hash=sha256:5bfd21b6acb32e20d4e279c34405a34e63da345be4b2b6eabd683e1a88857406 \
+    --hash=sha256:613cf06313331f49dd7b85a5a24fbddb1156c9723b6921a231906241726e5aee \
+    --hash=sha256:66a8e1c1e899d15a2f7510e43527fba22d895e7f6058d027db3e3837d88a69de \
+    --hash=sha256:691a62926ba09f2653ec0908554b3635497efb7751c5d46b916cd1ebbb1d3c25 \
+    --hash=sha256:6c1fd18e45c39d5a4be4b0d6a20c141e43fe46daeb1b2e2f304ebae7015ab6e6 \
+    --hash=sha256:6c6a1e8f98de92e817491b50aa4d01d69a1b41a4ed3173747e8f16f0d4cf81cc \
+    --hash=sha256:6cf029b886cfb28a2701503b7c602b811f2daa45276bd6459b0c71e051deb497 \
+    --hash=sha256:71506116eac0d3e3598d6325b4b818c3a0f6acb3222b24d30ad726e8c4bf7ea8 \
+    --hash=sha256:7993164e8e9f78ec31d38c47850ca6ba5451788b5b49a8a2dbb3322b36b5693b \
+    --hash=sha256:7a5cc6bf60791d8274edfdfe2dd7cec3f00f656dcc92e2b0a9af06c8b18ce6a6 \
+    --hash=sha256:87c1cc1057d903b78a8257a7c5f497db6fd5284f5080392bd57b66031d7389a3 \
+    --hash=sha256:98376c75bd6c103c74396953084a5e0798ffe476aecbfcc51ec6d100a685ac38 \
+    --hash=sha256:a395524b0fafa10446d11e11acb4742e919523de58aac03b791f26d7a783bcf0 \
+    --hash=sha256:a5100a4be91b7d4b7c8fe16a3600bd0951e10205eb1066b6873afd3996b51ee4 \
+    --hash=sha256:a63a52221f8c73f82f4e00493351d987f594931198589287aee96f8da673cfd5 \
+    --hash=sha256:a89734a7bcb2ea3b6fd600a74d6fbcdb8d3fa3f7917dbd978e039710b5509c9c \
+    --hash=sha256:b165f5e6de1ccc964e863bd2035807a4d3bad3e0481f9db2dc52034d6ad4f9de \
+    --hash=sha256:b3845e4c2fa32963fb7f384ebbaa2761b0e6b96145239bf80e956d4aff4b071c \
+    --hash=sha256:b3b017d9103e7a7372a146773be32b184ff7330bd708d40b1f56f06a686756ed \
+    --hash=sha256:b6c6e4858d8c3f88e19b7aa94b6a7619108f0bee51da9fa67b0785a8b59955f9 \
+    --hash=sha256:bfad1202fb1f9140e3810cc607058395f59032d9128cc0d716900c78bea5f337 \
+    --hash=sha256:c01809fb602e2fefc8cbfb3b603bb59d2a2eaee8708410896d48a835ba00e7c5 \
+    --hash=sha256:cce8de9d48289927ed18aaa420740efd52b2cd9289da32e3799afbb3a02822e8 \
+    --hash=sha256:ce2bc1ea01200b6d8130ab917296d05d77a1a571ec6c1ee25cfca6d55cd5db4a \
+    --hash=sha256:d4601e2a8b46ffbf540601a4926fd6cc5aae8a13b36fdd467f1040f01f9edaed \
+    --hash=sha256:d556d1c256b3700b60b6b061664a667b2e49d599c2772d46a9f2348f2dc4ab5c \
+    --hash=sha256:ddf7453acd03b966624ebefdb38169b5bbbeea1a1a58c90b095667247f9de327 \
+    --hash=sha256:e781eeb65b2007af553389c8a7fb7bc53cb856118b0fcffb2c26b0f49561c686 \
+    --hash=sha256:e920c272cd9e70a6b10eae9203cc96845da142e1dd4482de9343dda3738a9862 \
+    --hash=sha256:f5b6174bf4bf9152e368561dff410203c6921e4dd2afbcda3283a95957158112 \
+    --hash=sha256:f69bd42fd2515060af69b120668213121264bb7976b113954b6f9db327727c65 \
+    --hash=sha256:f823d0f6b04a6797fbe253bcf91666e71a6b63c290683819650c68b2468ebe64 \
+    --hash=sha256:fa7e9f2e80a9535f9692e113d02b4268b5f88675a730d1b0ef0abeb74c9a4e80
+    # via -r .github/requirements/bench.in
 talipp==2.7.0 \
    --hash=sha256:567f59ad74366cb59a14a00d350f35fd9d22e6924d6228bad581e6dcf1de2205 \
    --hash=sha256:f749f22b9ad615605e71faf26457bb7f5e3fe16f04d3287f4ca54fd16bc3d4eb
    # via -r .github/requirements/bench.in
+tulipy==0.4.0 \
+    --hash=sha256:540704956b5b940a5f6306aa393a37536a6d7c3cbc07efe47512f3496e5203ab \
+    --hash=sha256:95542e40537afdd345d875baf37485eac993c6a819d00c51432e9de8df21eba8 \
+    --hash=sha256:fbc31727ef7657c93ad910bfdce65fecc6aaa7a5e961fe00240718e7a3fc79d8
+    # via -r .github/requirements/bench.in
 tzdata==2026.2 \
    --hash=sha256:9173fde7d80d9018e02a662e168e5a2d04f87c41ea174b139fbef642eda62d10 \
    --hash=sha256:bbe9af844f658da81a5f95019480da3a89415801f6cc966806612cc7169bffe7
@@ -117,3 +117,29 @@ jobs:
        with:
          name: cross-library-bench
          path: bindings/python/benchmark.txt
+
+  rust-cross-bench:
+    name: Rust cross-library benchmark report
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+        with:
+          persist-credentials: false
+
+      - uses: dtolnay/rust-toolchain@29eef336d9b2848a0b548edc03f92a220660cdb8 # stable branch, 2026-03-27
+
+      - uses: Swatinem/rust-cache@e18b497796c12c097a38f9edb9d0641fb99eee32 # v2
+        continue-on-error: true # cache is an optimisation; never block on a stuck/slow restore
+        timeout-minutes: 6
+
+      # Wickra vs the other Rust TA crates (kand, ta-rs, yata) on an identical
+      # candle series — the like-for-like engine comparison with no binding
+      # overhead. Streaming + batch, in crates/wickra-bench/benches/cross_lib.rs.
+      - name: Run Rust cross-library benchmark
+        run: cargo bench -p wickra-bench --bench cross_lib | tee rust_cross_bench.txt
+
+      - name: Upload Rust report
+        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
+        with:
+          name: rust-cross-bench
+          path: rust_cross_bench.txt
@@ -180,14 +180,14 @@ jobs:
            exit 0
          fi
          cd docs-count
-          sed -i -E "s/[0-9]+ (streaming-first )?indicators/${n} \1indicators/g" index.md overview.md Indicators-Overview.md
+          sed -i -E "s/[0-9]+ (streaming-first )?indicators/${n} \1indicators/g" index.md overview.md Indicators-Overview.md .vitepress/config.ts
          if git diff --quiet; then
            echo "Docs indicator count unchanged."
            exit 0
          fi
          git config user.name "wickra-bot"
          git config user.email "wickra-bot@users.noreply.github.com"
-          git add index.md overview.md Indicators-Overview.md
+          git add index.md overview.md Indicators-Overview.md .vitepress/config.ts
          git commit -m "chore: sync indicator count to ${n}"
          if ! git push 2>/dev/null; then
            echo "::warning::push to wickra-lib/wickra-docs failed — ABOUT_SYNC_TOKEN likely lacks write (findings P10.0a)."
@@ -0,0 +1,96 @@
+# Benchmarks
+
+Read these as **relative** speedups on identical input — absolute µs depend on
+CPU, memory clock and OS scheduler, not a universal contract. **Streaming is the
+headline**: it is where Wickra's design pays off and where the gap is measured in
+orders of magnitude, not percent. The batch numbers come second and are shown
+honestly — the leanest crates edge Wickra out on the simple recurrences, and that
+is a deliberate trade for warmup/NaN semantics, not a ceiling.
+
+- **Reproduced on:** Windows 11 Pro 26200, AMD Ryzen 9 9950X, 64 GB DDR5,
+  Rust 1.92 (release: `lto = "fat"`, `codegen-units = 1`), Python 3.12.
+- **Reproduce yourself:**
+  - Rust core vs Rust crates: `cargo bench -p wickra-bench`
+  - Python vs Python libs: `pip install -e bindings/python[bench]` then
+    `python -m benchmarks.compare_libraries` (auto-detects installed peers).
+
+## 1. Streaming — the structural win
+
+Live trading feeds one tick at a time. Wickra updates every indicator in **O(1)**;
+batch-only libraries (TA-Lib, tulipy, finta, pandas-ta) have no incremental API
+and must recompute the whole history on every tick. Only `talipp` (Python) and
+`ta-rs` / `yata` (Rust) carry real per-tick state. This is the gap the library
+was built to expose.
+
+**Python — per-tick latency** (seed 5 000 bars, then feed ticks one at a time):
+
+| Indicator        | **★&nbsp;Wickra** | talipp           | TA-Lib (recompute)    |
+|------------------|------------------:|------------------|-----------------------|
+| SMA(20)          | **0.063 µs ★**    | 0.59 µs (9×)     | 204 µs (3 300×)       |
+| EMA(20)          | **0.060 µs ★**    | 0.72 µs (12×)    | 212 µs (3 500×)       |
+| RSI(14)          | **0.065 µs ★**    | 1.06 µs (16×)    | 230 µs (3 600×)       |
+| MACD(12, 26, 9)  | **0.078 µs ★**    | 4.22 µs (54×)    | 245 µs (3 100×)       |
+| Bollinger(20, 2) | **0.088 µs ★**    | 5.15 µs (58×)    | 229 µs (2 600×)       |
+
+Against the only other incremental Python peer Wickra is **9–58× faster**;
+against the recompute-on-every-tick libraries it is **2 600–14 000× faster**
+(`finta` RSI hits 14 000×). tulipy / pandas-ta land in the same recompute band
+as TA-Lib.
+
+**Rust — per-tick latency** (whole 50 000-bar series, lower = faster):
+
+| Indicator        | **★&nbsp;Wickra** | kand | ta-rs | yata |
+|------------------|------------------:|-----:|------:|-----:|
+| SMA(20)          | 50                | 38   | 47    | 38   |
+| EMA(20)          | 154               | 69   | 56    | 69   |
+| RSI(14)          | 164               | 216  | 74    | —    |
+| MACD(12, 26, 9)  | 275               | 143  | 66    | —    |
+| Bollinger(20, 2) | **128 ★**         | 248  | 168   | —    |
+| ATR(14)          | 152               | 166  | 61    | —    |
+
+`ta-rs` hands back a bare `f64` from the first tick with no warmup and no
+validation; it leads several rows by giving those guarantees up. Against `kand`,
+Wickra wins streaming RSI, Bollinger and ATR. `yata` exposes only SMA/EMA as
+raw-value methods, so its other rows are omitted rather than faked.
+
+## 2. Batch — competitive, not the headline
+
+Whole series in one call. Here hand-tuned C (`tulipy`, TA-Lib) and the leanest
+Rust crate (`kand`) win the simple recurrences — Wickra trades a few µs per pass
+for the `None`-warmup, NaN-safety and bit-exact `batch == streaming` guarantees
+none of them keep. It still wins several rows outright and beats the rest of the
+field everywhere.
+
+**Python** (20 000-bar pass, µs/op, lower = faster):
+
+| Indicator        | Wickra   | TA-Lib | tulipy | pandas-ta |
+|------------------|---------:|-------:|-------:|----------:|
+| SMA(20)          | 22.7     | **15.4** | 15.9 | 33.7      |
+| EMA(20)          | 30.8     | **30.3** | 31.1 | 48.8      |
+| RSI(14)          | 58.9     | 72.5   | **38.5** | 94.8    |
+| MACD(12, 26, 9)  | 71.7     | 99.1   | **33.5** | 207.6   |
+| Bollinger(20, 2) | 84.9     | 65.7   | **32.3** | 336.4   |
+| ATR(14)          | 52.0     | 79.4   | **31.9** | —        |
+
+Wickra beats TA-Lib on RSI, MACD and ATR and the whole Python field on every
+row; tulipy's SIMD C stays ahead on the heavier indicators.
+
+**Rust** (50 000-bar pass, µs, lower = faster). Only Wickra and `kand` expose a
+batch API; `ta-rs` and `yata` are streaming-only:
+
+| Indicator        | **★&nbsp;Wickra** | kand   |
+|------------------|------------------:|-------:|
+| SMA(20)          | 53                | **41** |
+| EMA(20)          | 111               | **71** |
+| RSI(14)          | **221 ★**         | 259    |
+| MACD(12, 26, 9)  | 533               | **327** |
+| Bollinger(20, 2) | **404 ★**         | 460    |
+| ATR(14)          | **122 ★**         | 169    |
+
+Run the suite yourself:
+
+```bash
+cargo bench -p wickra-bench            # Rust core vs kand / ta-rs / yata
+pip install -e bindings/python[bench]  # Python peers
+python -m benchmarks.compare_libraries
+```
@@ -7,6 +7,142 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0

 ## [Unreleased]

+## [0.6.6] - 2026-06-08
+- **Pivot Reversal** — a breakout signal when price closes through the most recently confirmed swing pivot (`PIVOT_REVERSAL`).
+- **Volume-Weighted Support/Resistance** — a band whose edges are the volume-weighted average of recent highs and lows (`VOLUME_WEIGHTED_SR`).
+- **Andrews Pitchfork** — median line and two parallels projected from the last three swing pivots (`ANDREWS_PITCHFORK`).
+- **Murrey Math Lines** — T. H. Murrey's eighths grid over the recent trading range, each level acting as support/resistance (`MURREY_MATH_LINES`).
+- **Central Pivot Range** — the classic pivot flanked by two central levels gauging the day's expected character (`CENTRAL_PIVOT_RANGE`).
+- **Faster scalar batch paths** — `Ema`, `Rsi`, `BollingerBands`, `MacdIndicator` and `Atr` gained dedicated batch fast paths (used by the Python bindings) that strip per-element `Option`/validation overhead and the intermediate `Vec<Option<_>>` allocation, while staying *bit-for-bit* equal to replaying `update` (including the SMA/Bollinger drift-reseed). Python batch is ~2× faster on EMA/RSI/MACD/ATR; streaming is unchanged.
+- **Cross-library benchmark refresh** — `benchmarks/compare_libraries.py` now measures the median across timing rounds (`--rounds` / `--streaming-rounds`), adds `--skip-batch` / `--skip-streaming`, and drives every peer through the streaming arena (recompute for batch-only libraries). `wickra-bench` compares the batch fast paths against `kand`.
+
+## [0.6.5] - 2026-06-07
+- **Autocorrelation Periodogram** — Ehlers autocorrelation periodogram: dominant cycle period estimate (`AUTOCORRPGRAM`).
+- **Even Better Sinewave** — Ehlers Even Better Sinewave: normalized cycle-phase oscillator (`EVENBETTERSINE`).
+- **Bandpass Filter** — Ehlers bandpass filter: isolates a frequency band around the dominant cycle (`BANDPASS`).
+- **Adaptive CCI** — Adaptive CCI: efficiency-ratio-adaptive CCI on typical price (`ADAPTIVECCI`).
+- **Universal Oscillator** — Ehlers Universal Oscillator: SuperSmoother-based normalized cycle oscillator (`UNIVERSALOSC`).
+- **Adaptive RSI** — Adaptive RSI: dominant-cycle-tuned RSI length (Ehlers) (`ADAPTIVERSI`).
+- **Correlation Trend Indicator** — Ehlers Correlation Trend Indicator: Pearson correlation of price vs time (`CTI`).
+- **Trendflex** — Ehlers Trendflex: trend-following companion to Reflex (`TRENDFLEX`).
+- **Reflex** — Ehlers Reflex: trend-cycle oscillator measuring slope-adjusted displacement (`REFLEX`).
+- **Highpass Filter** — Ehlers highpass filter: removes low-frequency trend, leaving cyclic component (`HIGHPASS`).
+
+## [0.6.4] - 2026-06-07
+- **Kendall Tau** — Kendall rank correlation (tau-b) over a rolling window of paired observations (`KENDALLTAU`).
+- **Sample Entropy** — Sample entropy: regularity/complexity of a rolling series (Richman-Moorman) (`SAMPLEENT`).
+- **Shannon Entropy** — Shannon entropy of a rolling value distribution over fixed bins (`SHANNONENT`).
+- **Rolling Min-Max Scaler** — Rolling min-max scaler mapping the latest value to 0..1 over a rolling window (`ROLLINGMINMAX`).
+- **Jarque-Bera** — Jarque-Bera normality test statistic over a rolling window (`JARQUEBERA`).
+
+## [0.6.3] - 2026-06-07
+- **Volume-Weighted MACD** — Volume-Weighted MACD: MACD computed on VWMA instead of EMA, with signal line and histogram (`VWMACD`).
+- **Better Volume** — Better Volume (VSA): classifies volume against bar spread to surface effort/result imbalance (`BETTERVOL`).
+- **Intraday Intensity Index** — Intraday Intensity Index: volume weighted by close position within the bar range (`INTRADAYINT`).
+- **Trade Volume Index** — Trade Volume Index: accumulates volume by tick direction past a min-tick threshold (distinct from TSV) (`TRADEVOLIDX`).
+- **Twiggs Money Flow** — Twiggs Money Flow: volume-weighted accumulation using true range and Wilder smoothing (distinct from CMF) (`TWIGGSMF`).
+- **Williams Accumulation/Distribution** — Williams Accumulation/Distribution: cumulative price-direction accumulator (distinct from Chaikin A/D) (`WILLIAMSAD`).
+- **Volume RSI** — Volume RSI: Wilder-style RSI computed on signed volume flow (`VOLUMERSI`).
+
+## [0.6.2] - 2026-06-07
+- **Modified MA Stop** — Modified MA Stop — SMMA-ratcheted trailing stop with directional flip (`MODIFIED_MA_STOP`).
+- **Time-Based Stop** — Time-Based Stop — bar-count timer that fires after a fixed holding period (`TIME_BASED_STOP`).
+- **NRTR** — NRTR (Nick Rypock Trailing Reverse) — percentage trailing-reverse stop (`NRTR`).
+- **ATR Ratchet** — ATR Ratchet — Kaufman per-bar tightening volatility trailing stop (`ATR_RATCHET`).
+- **Elder SafeZone** — Elder SafeZone Stop — average noise-penetration trailing stop with directional flip (`ELDER_SAFE_ZONE`).
+- **Kase DevStop** — Kase DevStop volatility trailing stop using standard-deviation of two-bar true range (`KASE_DEV_STOP`).
+
+## [0.6.1] - 2026-06-07
+- **Projection Oscillator** — Widner projection oscillator: close position inside the projection bands, scaled 0..100 (`ProjectionOscillator`).
+- **Projection Bands** — Widner projection bands: forward-projected high/low regression envelope (`ProjectionBands`).
+- **Median Channel** — robust median +/- multiplier*MAD envelope (`MedianChannel`).
+- **Bomar Bands** — adaptive percentage bands containing a target coverage fraction of recent closes (`BomarBands`).
+- **Quartile Bands** — rolling 25th/50th/75th-percentile (Q1/median/Q3) envelope (`QuartileBands`).
+
+## [0.6.0] - 2026-06-06
+- **Volatility Cone** — volatility cone: current realized volatility within its historical min/median/max envelope (`VolatilityCone`).
+- **VolatilityRatio** — Schwager's volatility ratio: true range over the EMA of prior true ranges (`VolatilityRatio`).
+- **BipowerVariation** — jump-robust realized bipower variation (pi/2 sum of adjacent absolute log-return products) (`BipowerVariation`).
+- **VolatilityOfVolatility** — vol-of-vol: sample stddev of a rolling realized-volatility series (`VolatilityOfVolatility`).
+- **Garch11** — GARCH(1,1) conditional volatility with a long-run-variance anchor (`Garch11`).
+- **EwmaVolatility** — RiskMetrics exponentially-weighted volatility of log returns (lambda decay) (`EwmaVolatility`).
+
+## [0.5.9] - 2026-06-06
+
+### Added
+
+- Internal Rust cross-library benchmark harness (`crates/wickra-bench`, not
+  published) comparing Wickra against `kand`, `ta-rs` and `yata` on an identical
+  candle series in both streaming and batch modes; wired into the nightly
+  `cross-library-bench` workflow.
+- `tulipy` runners and expanded per-tick streaming coverage (SMA, EMA, RSI,
+  MACD, Bollinger) in the Python `compare_libraries` benchmark.
+
+### Changed
+
+- Faster streaming and batch updates for SMA, Bollinger Bands, RSI, EMA and ATR
+  (flat ring buffers replacing `VecDeque`, hoisted reciprocals in the Wilder
+  smoothing, leaner hot state) — indicator outputs are unchanged.
+- Rewrote the README benchmark section into honest, tiered tables (Rust core vs
+  the other Rust crates, and Python vs the Python ecosystem) that show where
+  Wickra wins and where it loses, not only the favourable comparisons.
+
+## [0.5.8] - 2026-06-04
+- **TSF Oscillator** — the percentage gap of the close to the one-bar-ahead time-series forecast, a close-relative companion to CFO (`TsfOscillator`).
+- **MACD Histogram** — the standalone macd-minus-signal bar of MACD as a scalar series (`MacdHistogram`).
+- **PPO Histogram** — the Percentage Price Oscillator with its signal EMA and the resulting zero-centered histogram (`PpoHistogram`).
+
+## [0.5.7] - 2026-06-04
+- **Qstick** — Qstick (Chande), the SMA of the candle body (close − open) as a net buying/selling pressure gauge (`QSTICK`).
+- **TTM Trend** — TTM Trend (John Carter), +1/−1 by whether the close sits above the SMA of recent median prices (`TTM_TREND`).
+- **Trend Strength Index** — trend strength index, the signed r² of a linear regression of price against time (`TREND_STRENGTH_INDEX`).
+- **Polarized Fractal Efficiency** — polarized fractal efficiency (Hannula), directional trend efficiency over a fractal lookback (`POLARIZED_FRACTAL_EFFICIENCY`).
+- **Wave PM** — Wave PM (Kase), a variance-normalised peak-momentum statistic (`WAVE_PM`).
+- **Gator Oscillator** — Gator Oscillator (Bill Williams), the Alligator convergence/divergence histogram (`GATOR_OSCILLATOR`).
+- **Kase Permission Stochastic** — Kase Permission Stochastic, a double-smoothed stochastic used as a trade-permission filter (`KASE_PERMISSION_STOCHASTIC`).
+
+## [0.5.6] - 2026-06-04
+- **QQE** — quantitative qualitative estimation, a smoothed RSI with an ATR-of-RSI trailing line (`QQE`).
+- **Intraday Momentum Index** — intraday momentum index (Chande), RSI on the open-to-close body (`IMI`).
+- **Elder Ray** — Elder Ray bull power and bear power around an EMA of close (`ElderRay`).
+- **Derivative Oscillator** — derivative oscillator (Constance Brown), a double-smoothed RSI histogram (`DerivativeOscillator`).
+- **RMI** — relative momentum index (RMI), RSI over a multi-bar momentum lookback (`RMI`).
+- **Stochastic CCI** — stochastic CCI, a stochastic oscillator over the CCI (`StochasticCCI`).
+- **Dynamic Momentum Index** — dynamic momentum index (Chande), a volatility-adaptive RSI (`DynamicMomentumIndex`).
+- **RSX** — RSX, a Jurik-style three-stage smoothed RSI (`RSX`).
+- **Fisher RSI** — Fisher RSI, the Fisher transform of a normalised RSI (`FisherRSI`).
+- **Disparity Index** — disparity index, the percent gap between price and its moving average (`DisparityIndex`).
+
+## [0.5.5] - 2026-06-04
+- **GD** — generalized DEMA (GD), Tillson's volume-factor double EMA and the building block of T3 (`GD`).
+- **GMA** — geometric moving average (GMA), the rolling geometric mean of prices (`GMA`).
+- **Holt-Winters** — Holt's linear (double exponential) smoothing with level and trend components (`HoltWinters`).
+- **Adaptive Laguerre** — Ehlers adaptive Laguerre filter with median-error-adaptive gamma (`AdaptiveLaguerre`).
+- **Median MA** — median moving average, the rolling median of prices (`MedianMA`).
+- **EHMA** — exponential Hull moving average (EHMA), the Hull construction built from EMAs (`EHMA`).
+- **SWMA** — sine-weighted moving average (SWMA), a symmetric half-cycle sine window (`SWMA`).
+
+## [0.5.4] - 2026-06-04
+- **Roll Measure** — effective spread implied by the negative serial covariance of trade-price changes (Roll 1984) (`RollMeasure`).
+- **Amihud Illiquidity** — average absolute log return per unit of traded value (price-impact liquidity proxy, Amihud 2002) (`AmihudIlliquidity`).
+- **VPIN** — volume-synchronised probability of informed trading (volume-bucketed order-flow toxicity) (`Vpin`).
+- **Order Flow Imbalance** — rolling sum of best-level order-flow events (Cont-Kukanov-Stoikov OFI) (`OrderFlowImbalance`).
+- **Expectancy** — expected return per unit of average loss (R-multiple) over a rolling window of returns (`Expectancy`).
+- **Win Rate** — fraction of strictly-positive returns over a rolling window (`WinRate`).
+- **Regime Label** — volatility-quantile regime classification: −1 calm / 0 normal / +1 stressed, by where the rolling volatility sits in its own recent distribution (`RegimeLabel`).
+- **Jump Indicator** — flags return outliers beyond `threshold ×` trailing return volatility (−1 down / 0 / +1 up) (`JumpIndicator`).
+- **Trend Label** — discrete trend state from the sign of the rolling least-squares slope (−1 / 0 / +1) (`TrendLabel`).
+- **High-Low Range** — bar high-low range as a fraction of close (scale-free per-bar volatility) (`HighLowRange`).
+- **Wick Ratio** — signed upper-vs-lower shadow imbalance as a fraction of the range (`WickRatio`).
+- **Body Size Percent** — absolute candle body as a fraction of the bar range (`BodySizePct`).
+- **Close vs Open** — signed body as a fraction of the open price, `(close − open) / open` (`CloseVsOpen`).
+- **Spread AR(1) Coefficient** — first-order autoregression coefficient of the spread `a − b` (direct cointegration / mean-reversion strength) (`SpreadAr1Coefficient`).
+- **Rolling Quantile** — interpolated q-th quantile over a trailing window (type-7 / NumPy default) (`RollingQuantile`).
+- **Rolling Percentile Rank** — percentile rank of the latest value within its trailing window (`RollingPercentileRank`).
+- **Rolling IQR** — interquartile range (Q3 − Q1) over a trailing window (robust dispersion) (`RollingIqr`).
+- **Realized Volatility** — square root of the summed squared log returns (raw, un-annualised quadratic variation) (`RealizedVolatility`).
+- **Log Return** — logarithmic return over a fixed lag, `ln(price_t / price_{t−period})` (`LogReturn`).
+
 ## [0.5.3] - 2026-06-04
 - **Fibonacci Time Zones** — vertical markers at Fibonacci bar-distances (1/2/3/5/8/...) from the latest swing pivot (`FIB_TIME_ZONES`).
 - **Fibonacci Channel** — a sloped base trendline plus parallel lines at Fibonacci multiples of the channel width (`FIB_CHANNEL`).
@@ -1217,7 +1353,20 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
  optional Binance live feed.
 - Bindings for Python, Node.js, and WebAssembly.

-[Unreleased]: https://github.com/wickra-lib/wickra/compare/v0.5.3...HEAD
+[Unreleased]: https://github.com/wickra-lib/wickra/compare/v0.6.6...HEAD
+[0.6.6]: https://github.com/wickra-lib/wickra/compare/v0.6.5...v0.6.6
+[0.6.5]: https://github.com/wickra-lib/wickra/compare/v0.6.4...v0.6.5
+[0.6.4]: https://github.com/wickra-lib/wickra/compare/v0.6.3...v0.6.4
+[0.6.3]: https://github.com/wickra-lib/wickra/compare/v0.6.2...v0.6.3
+[0.6.2]: https://github.com/wickra-lib/wickra/compare/v0.6.1...v0.6.2
+[0.6.1]: https://github.com/wickra-lib/wickra/compare/v0.6.0...v0.6.1
+[0.6.0]: https://github.com/wickra-lib/wickra/compare/v0.5.9...v0.6.0
+[0.5.9]: https://github.com/wickra-lib/wickra/compare/v0.5.8...v0.5.9
+[0.5.8]: https://github.com/wickra-lib/wickra/compare/v0.5.7...v0.5.8
+[0.5.7]: https://github.com/wickra-lib/wickra/compare/v0.5.6...v0.5.7
+[0.5.6]: https://github.com/wickra-lib/wickra/compare/v0.5.5...v0.5.6
+[0.5.5]: https://github.com/wickra-lib/wickra/compare/v0.5.4...v0.5.5
+[0.5.4]: https://github.com/wickra-lib/wickra/compare/v0.5.3...v0.5.4
 [0.5.3]: https://github.com/wickra-lib/wickra/compare/v0.5.2...v0.5.3
 [0.5.2]: https://github.com/wickra-lib/wickra/compare/v0.5.1...v0.5.2
 [0.5.1]: https://github.com/wickra-lib/wickra/compare/v0.5.0...v0.5.1
@@ -702,6 +702,16 @@ dependencies = [
 "wasm-bindgen",
 ]

+[[package]]
+name = "kand"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "af1f41590bd014ef6c3dd815b45f07deb4c3198e355a4319bb7521b6a3a6aeb5"
+dependencies = [
+ "num_enum",
+ "thiserror",
+]
+
 [[package]]
 name = "leb128fmt"
 version = "0.1.0"
@@ -911,6 +921,28 @@ dependencies = [
 "libm",
 ]

+[[package]]
+name = "num_enum"
+version = "0.7.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5d0bca838442ec211fa11de3a8b0e0e8f3a4522575b5c4c06ed722e005036f26"
+dependencies = [
+ "num_enum_derive",
+ "rustversion",
+]
+
+[[package]]
+name = "num_enum_derive"
+version = "0.7.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "680998035259dcfcafe653688bf2aa6d3e2dc05e98be6ab46afb089dc84f1df8"
+dependencies = [
+ "proc-macro-crate",
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "numpy"
 version = "0.28.0"
@@ -1081,6 +1113,15 @@ dependencies = [
 "syn",
 ]

+[[package]]
+name = "proc-macro-crate"
+version = "3.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e67ba7e9b2b56446f1d419b1d807906278ffa1a658a8a5d8a39dcb1f5a78614f"
+dependencies = [
+ "toml_edit",
+]
+
 [[package]]
 name = "proc-macro2"
 version = "1.0.106"
@@ -1498,6 +1539,12 @@ dependencies = [
 "syn",
 ]

+[[package]]
+name = "ta"
+version = "0.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "609409d472a0a7d8d4dd9e19891bbdef546b9dce670c3057d0e02192dc541226"
+
 [[package]]
 name = "target-lexicon"
 version = "0.13.5"
@@ -1607,6 +1654,36 @@ dependencies = [
 "tungstenite",
 ]

+[[package]]
+name = "toml_datetime"
+version = "1.1.1+spec-1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3165f65f62e28e0115a00b2ebdd37eb6f3b641855f9d636d3cd4103767159ad7"
+dependencies = [
+ "serde_core",
+]
+
+[[package]]
+name = "toml_edit"
+version = "0.25.12+spec-1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d2153edc6955a6c354fad8f5efd38b6a8769bdccf9fe50f8e1329f81b0baa5d7"
+dependencies = [
+ "indexmap",
+ "toml_datetime",
+ "toml_parser",
+ "winnow",
+]
+
+[[package]]
+name = "toml_parser"
+version = "1.1.2+spec-1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a2abe9b86193656635d2411dc43050282ca48aa31c2451210f4202550afb7526"
+dependencies = [
+ "winnow",
+]
+
 [[package]]
 name = "tungstenite"
 version = "0.29.0"
@@ -1867,7 +1944,7 @@ dependencies = [

 [[package]]
 name = "wickra"
-version = "0.5.3"
+version = "0.6.6"
 dependencies = [
 "approx",
 "criterion",
@@ -1876,9 +1953,21 @@ dependencies = [
 "wickra-data",
 ]

+[[package]]
+name = "wickra-bench"
+version = "0.6.6"
+dependencies = [
+ "criterion",
+ "kand",
+ "ta",
+ "wickra",
+ "wickra-data",
+ "yata",
+]
+
 [[package]]
 name = "wickra-core"
-version = "0.5.3"
+version = "0.6.6"
 dependencies = [
 "approx",
 "proptest",
@@ -1888,7 +1977,7 @@ dependencies = [

 [[package]]
 name = "wickra-data"
-version = "0.5.3"
+version = "0.6.6"
 dependencies = [
 "approx",
 "csv",
@@ -1905,7 +1994,7 @@ dependencies = [

 [[package]]
 name = "wickra-examples"
-version = "0.0.0"
+version = "0.6.6"
 dependencies = [
 "serde_json",
 "tokio",
@@ -1915,7 +2004,7 @@ dependencies = [

 [[package]]
 name = "wickra-node"
-version = "0.5.3"
+version = "0.6.6"
 dependencies = [
 "napi",
 "napi-build",
@@ -1925,7 +2014,7 @@ dependencies = [

 [[package]]
 name = "wickra-python"
-version = "0.5.3"
+version = "0.6.6"
 dependencies = [
 "numpy",
 "pyo3",
@@ -1934,7 +2023,7 @@ dependencies = [

 [[package]]
 name = "wickra-wasm"
-version = "0.5.3"
+version = "0.6.6"
 dependencies = [
 "console_error_panic_hook",
 "js-sys",
@@ -1991,6 +2080,15 @@ dependencies = [
 "windows-link",
 ]

+[[package]]
+name = "winnow"
+version = "1.0.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0592e1c9d151f854e6fd382574c3a0855250e1d9b2f99d9281c6e6391af352f1"
+dependencies = [
+ "memchr",
+]
+
 [[package]]
 name = "wit-bindgen"
 version = "0.51.0"
@@ -2091,6 +2189,15 @@ version = "0.6.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1ffae5123b2d3fc086436f8834ae3ab053a283cfac8fe0a0b8eaae044768a4c4"

+[[package]]
+name = "yata"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6b4ef8ddfa3ccd93454262c0e60a43a2bbf403d404174e1815f7581d5028229f"
+dependencies = [
+ "serde",
+]
+
 [[package]]
 name = "yoke"
 version = "0.8.2"
@@ -8,11 +8,12 @@ members = [
    "bindings/wasm",
    "bindings/node",
    "examples/rust",
+    "crates/wickra-bench",
 ]
 exclude = ["fuzz"]

 [workspace.package]
-version = "0.5.3"
+version = "0.6.6"
 authors = ["kingchenc <support@wickra.org>"]
 edition = "2021"
 rust-version = "1.86"
@@ -24,7 +25,7 @@ keywords = ["finance", "trading", "indicators", "technical-analysis", "ta"]
 categories = ["finance", "mathematics", "science"]

 [workspace.dependencies]
-wickra-core = { path = "crates/wickra-core", version = "0.5.3" }
+wickra-core = { path = "crates/wickra-core", version = "0.6.6" }

 thiserror = "2"
 rayon = "1.10"
@@ -1,5 +1,5 @@
 <p align="center">
-  <a href="https://wickra.org"><img src="https://raw.githubusercontent.com/wickra-lib/.github/main/profile/wickra-banner.webp?v=377" alt="Wickra — streaming-first technical indicators" width="100%"></a>
+  <a href="https://wickra.org"><img src="https://raw.githubusercontent.com/wickra-lib/.github/main/profile/wickra-banner.webp?v=467" alt="Wickra — streaming-first technical indicators" width="100%"></a>
 </p>

 [![CI](https://github.com/wickra-lib/wickra/actions/workflows/ci.yml/badge.svg)](https://github.com/wickra-lib/wickra/actions/workflows/ci.yml)
@@ -48,7 +48,7 @@ Full documentation lives at **[docs.wickra.org](https://docs.wickra.org)**:
  [Node](https://docs.wickra.org/Quickstart-Node),
  [WASM](https://docs.wickra.org/Quickstart-WASM).
 - **Indicators** — a per-indicator deep dive (formula, parameters, warmup) for
-  every one of the 377 indicators; start at the
+  every one of the 467 indicators; start at the
  [indicators overview](https://docs.wickra.org/Indicators-Overview).
 - **Reference** — [warmup periods](https://docs.wickra.org/Warmup-Periods),
  [streaming vs batch](https://docs.wickra.org/Streaming-vs-Batch),
@@ -58,102 +58,94 @@ Full documentation lives at **[docs.wickra.org](https://docs.wickra.org)**:
  [TA-Lib migration](https://docs.wickra.org/TA-Lib-Migration),
  [FAQ](https://docs.wickra.org/FAQ).

+## Why Wickra
+
+Most TA libraries are fast, *or* multi-language, *or* broad. Wickra refuses to
+pick. It's the streaming-first engine built for the workload the others treat as
+an afterthought — **live, tick-by-tick data** — without giving up the breadth of
+a full batch library, and without making you reimplement your indicators four
+times to get there.
+
+- **The biggest streaming-native catalogue, period.** 467 indicators across 24
+  families — candlesticks, harmonic & chart patterns, market profile, market
+  breadth, Renko/Kagi/Point&Figure bars, Ehlers DSP cycles, risk/performance
+  metrics — every single one updating in **O(1) per tick**. TA-Lib ships ~150 and
+  none of them stream.
+- **One Rust core, four first-class targets.** Native **Python · Node.js ·
+  WebAssembly · Rust** — identical math, identical results, zero per-language
+  reimplementation and zero GIL bottleneck.
+- **Correct by construction, not by hope.** Every `update` validates its input,
+  runs a real warmup, and returns an `Option` so a single bad tick can't silently
+  poison state. `batch == streaming` is **bit-exact, fuzzed and 100 %-line-covered
+  for all 467 indicators**.
+- **Orders of magnitude faster where it counts.** In streaming Wickra is **9–58×**
+  faster than the only other incremental peer and **thousands of times** faster
+  than recompute-on-every-tick libraries. On batch it wins several rows outright
+  and trades the simple recurrences (SMA, EMA, MACD) for its guarantees — and
+  the losses are shown, not hidden.
+- **Install in one line, anywhere.** `pip install wickra` / `npm install wickra` —
+  precompiled wheels and binaries, **no C toolchain, none of TA-Lib's setup pain**.
+  macOS · Linux · Windows.
+- **Batteries included.** Indicator chaining, a streaming OHLCV CSV reader, and a
+  live Binance kline feed ship in the box.
+- **Truly permissive.** **MIT OR Apache-2.0** — drop it straight into commercial
+  and closed-source work.
+
+Every other library forces one of those compromises. Wickra doesn't:
+
+| Library          | Install     | Streaming   | Languages                   | Indicators | Active |
+|------------------|-------------|-------------|-----------------------------|-----------:|--------|
+| **★&nbsp;Wickra**| **clean**   | **yes, O(1)** | **Python · Node · WASM · Rust** | **467** | **yes** |
+| kand             | clean       | yes         | Python · WASM · Rust        |       ~60  | yes    |
+| ta-rs            | clean       | yes         | Rust only                   |       ~30  | stale  |
+| yata             | clean       | partial     | Rust only                   |       ~35  | yes    |
+| TA-Lib           | yes (C deps)| no          | many bindings               |      ~150  | barely |
+| pandas-ta        | clean       | no          | Python                      |      ~130  | slow   |
+| finta            | clean       | no          | Python                      |       ~80  | stale  |
+| talipp           | clean       | yes         | Python                      |       ~40  | yes    |
+
+Broad, multi-language, streaming-native **and** honest about its trade-offs — at
+the same time. That's the combination no one else ships.
+
 ## Why Wickra exists

-The Python TA ecosystem has plenty of libraries — TA-Lib, pandas-ta, finta,
-talipp, tulipy — and every one of them shares the same blind spot:
+Wickra started as a personal itch. The existing TA libraries never quite fit the
+projects I was building, so I decided to build one from the ground up — partly to
+learn, partly because I genuinely enjoy taking something that already exists and
+trying to do it differently (and, ideally, better). It's open source because the
+useful version of that itch is the one other people can build on too.

-| Library                | Install pain    | Streaming | Multi-language | Active |
-|------------------------|-----------------|-----------|----------------|--------|
-| **★&nbsp;Wickra**      | **clean**       | **yes**   | **Python + Node + WASM + Rust** | **yes** |
-| TA-Lib (Python)        | yes (C deps)    | no        | no             | barely |
-| pandas-ta              | clean           | no        | no             | slow   |
-| finta                  | clean           | no        | no             | stale  |
-| ta-lib-python          | yes (C deps)    | no        | no             | barely |
-| talipp                 | clean           | yes       | no             | yes    |
-| Tulip Indicators       | yes (C deps)    | no        | partial        | stale  |
-| ooples (C#)            | clean           | no        | C# only        | yes    |
+## Benchmarks

-Wickra is the only library that combines all of: clean install, streaming,
-multi-language reach, and active maintenance.
+Wickra updates every indicator in **O(1)** per tick. In **streaming** — the
+workload it is built for — it is **9–58× faster** than the only other incremental
+peer and **thousands of times** faster than recompute-on-every-tick libraries.
+**Batch** is competitive: it wins several rows outright and trades a few µs
+elsewhere for `None`-warmup, NaN-safety and bit-exact `batch == streaming`.

-## Benchmark: how much faster is "streaming-first"?
-
-The numbers below were measured on a single developer workstation and are not
-guaranteed to reproduce identically on different hardware — absolute µs values
-depend on CPU, memory clock and OS scheduler. Read them as **relative
-speedups** between libraries on identical input, not as a universal
-performance contract.
-
- **Reproduced on:** Windows 11 Pro 26200, AMD Ryzen 9 9950X, 64 GB DDR5,
-  Rust 1.92 (release profile, `lto = "fat"`, `codegen-units = 1`),
-  Python 3.12, Node 20.
- **Reproduce yourself:** `pip install -e bindings/python[bench]` then
-  `python -m benchmarks.compare_libraries`. The script auto-detects every
-  installed peer library and runs them on the same generated inputs as
-  Wickra. The CI job `cross-library-bench` runs the same script on every
-  push and uploads the raw report as a build artefact.
-
-Lower µs/op = faster. Wickra wins every batch category outright, and the
-streaming gap widens linearly with how much history a batch-only library has
-to recompute on every tick.
-
-### Batch — single full pass over a 20 000-bar series
-
-Reading the table: each cell shows that library's runtime, plus how many times
-slower it is than Wickra in parentheses. **★** marks the winner per row.
-
-| Indicator           | **★&nbsp;Wickra**   | finta                       | talipp                        |
-|---------------------|---------------------|-----------------------------|-------------------------------|
-| SMA(20)             | **95.6 µs ★**       | 343.5 µs (3.6× slower)      | 7 640.6 µs (79.9× slower)     |
-| EMA(20)             | **64.6 µs ★**       | 223.1 µs (3.5× slower)      | 12 160.9 µs (188.2× slower)   |
-| RSI(14)             | **126.2 µs ★**      | 1 107.1 µs (8.8× slower)    | 15 792.2 µs (125.1× slower)   |
-| MACD(12, 26, 9)     | **119.0 µs ★**      | 531.8 µs (4.5× slower)      | 49 788.1 µs (418.2× slower)   |
-| Bollinger(20, 2.0)  | **105.3 µs ★**      | 812.0 µs (7.7× slower)      | 130 938.3 µs (1 243.7× slower)|
-| ATR(14)             | **123.5 µs ★**      | 5 144.8 µs (41.7× slower)   | 28 816.0 µs (233.4× slower)   |
-
-### Streaming — per-tick latency after seeding with 5 000 historical bars
-
-A batch-only library has to re-run its full indicator over the entire history on
-every new tick; Wickra updates state in O(1).
-
-| Indicator | **★&nbsp;Wickra (per tick)** | talipp (per tick)         |
-|-----------|---------------------|---------------------------|
-| RSI(14)   | **0.119 µs ★**      | 1.644 µs (13.8× slower)   |
-
-> TA-Lib and pandas-ta are not included here because both fail to install
-> cleanly on Windows without C build tooling — which is precisely the install
-> pain Wickra was built to remove. The benchmark script auto-detects every
-> peer library it can find and runs them on the same inputs as Wickra; install
-> them in your environment to see those rows light up too.
-
-Run the suite yourself:
-
-```bash
-pip install -e bindings/python[bench]
-python -m benchmarks.compare_libraries
-```
+Full tables (Rust + Python, streaming + batch) and how to reproduce them live in
+**[BENCHMARKS.md](BENCHMARKS.md)**.

 ## Indicators

-377 streaming-first indicators across twenty-four families. Every one passes the
+467 streaming-first indicators across twenty-four families. Every one passes the
 `batch == streaming` equivalence test, reference-value tests, and reset
 semantics tests. Each has a per-indicator deep dive (formula, parameters,
 warmup) at [docs.wickra.org](https://docs.wickra.org/Indicators-Overview).

 | Family | Indicators |
 |--------|-----------|
-| Moving Averages      | SMA, EMA, WMA, DEMA, TEMA, HMA, KAMA, SMMA, TRIMA, ZLEMA, T3, VWMA, ALMA, McGinley Dynamic, FRAMA, VIDYA, JMA, Alligator, EVWMA |
-| Momentum Oscillators | RSI (Wilder), Anchored RSI, Stochastic, CCI, ROC, Williams %R, MFI, Awesome Oscillator, MOM, CMO, TSI, PMO, StochRSI, Ultimate Oscillator, RVI, PGO, KST, SMI, Laguerre RSI, Connors RSI, Inertia, ROC Percentage (ROCP), ROC Ratio (ROCR), ROC Ratio 100 (ROCR100) |
-| Trend & Directional  | MACD, MACD Fixed (MACDFIX), MACD Extended (MACDEXT), ADX (+DI/-DI), ADXR, Aroon, TRIX, Aroon Oscillator, Vortex, Random Walk Index, Trend Intensity Index, Wave Trend Oscillator, Mass Index, Choppiness Index, Vertical Horizontal Filter, Plus DM, Minus DM, Plus DI, Minus DI, DX |
-| Price Oscillators    | PPO, DPO, Coppock, Accelerator Oscillator, Balance of Power, APO, AO Histogram, CFO, Zero-Lag MACD, Elder Impulse, STC |
-| Volatility & Bands   | ATR, Bollinger Bands, Keltner Channels, Donchian Channels, NATR, StdDev, Ulcer Index, Historical Volatility, Bollinger Bandwidth, %B, True Range, Chaikin Volatility, RVI (Relative Volatility Index), Parkinson Volatility, Garman-Klass Volatility, Rogers-Satchell Volatility, Yang-Zhang Volatility |
-| Bands & Channels     | MA Envelope, Acceleration Bands, STARC Bands, ATR Bands, Hurst Channel, LinReg Channel, Standard Error Bands, Double Bollinger Bands, TTM Squeeze, Fractal Chaos Bands, VWAP StdDev Bands |
-| Trailing Stops       | Parabolic SAR, Parabolic SAR Extended (SAREXT), SuperTrend, Chandelier Exit, Chande Kroll Stop, ATR Trailing Stop, HiLo Activator, Volty Stop, Yo-Yo Exit, Donchian Channel Stop, Percentage Trailing Stop, Step Trailing Stop, Renko Trailing Stop |
-| Volume               | OBV, VWAP (cumulative + rolling), ADL, Volume-Price Trend, Chaikin Money Flow, Chaikin Oscillator, Force Index, Ease of Movement, Klinger Volume Oscillator, Volume Oscillator, NVI, PVI, Williams A/D, Anchored VWAP, Demand Index, TSV, VZO, Market Facilitation Index |
-| Price Statistics     | Typical Price, Median Price, Weighted Close, Linear Regression, Linear Regression Slope, Z-Score, Linear Regression Angle, Variance, Coefficient of Variation, Skewness, Kurtosis, Standard Error, Detrended StdDev, R², Median Absolute Deviation, Autocorrelation, Hurst Exponent, Pearson Correlation, Beta, Pairwise Beta, Pair Spread Z-Score, Lead-Lag Cross-Correlation, Cointegration, Relative Strength A-vs-B, Spearman Correlation, Mid Price, Mid Point, Average Price, Linear Regression Intercept, Time Series Forecast, Rolling Correlation, Rolling Covariance, OU Half-Life, Spread Hurst, Distance SSD, Beta-Neutral Spread, Variance Ratio, Granger Causality, Kalman Hedge Ratio, Spread Bollinger Bands |
-| Ehlers / Cycle (DSP) | MAMA, FAMA, Fisher Transform, Inverse Fisher Transform, SuperSmoother, Hilbert Dominant Cycle, Hilbert Phasor, Hilbert DC Phase, Hilbert Trend Mode, Sine Wave, Decycler, Decycler Oscillator, Roofing Filter, Center of Gravity, Cybernetic Cycle, Adaptive Cycle, Empirical Mode Decomposition, Ehlers Stochastic, Instantaneous Trendline |
-| Pivots & S/R         | Classic Pivots, Fibonacci Pivots, Camarilla, Woodie Pivots, DeMark Pivots, Williams Fractals, ZigZag |
+| Moving Averages      | SMA, EMA, WMA, DEMA, TEMA, HMA, KAMA, SMMA, TRIMA, ZLEMA, T3, VWMA, ALMA, McGinley Dynamic, FRAMA, VIDYA, JMA, Alligator, EVWMA, SWMA, GMA, EHMA, Median MA, Adaptive Laguerre, GD, Holt-Winters |
+| Momentum Oscillators | RSI (Wilder), Anchored RSI, Stochastic, CCI, ROC, Williams %R, MFI, Awesome Oscillator, MOM, CMO, TSI, PMO, StochRSI, Ultimate Oscillator, RVI, PGO, KST, SMI, Laguerre RSI, Connors RSI, Inertia, ROC Percentage (ROCP), ROC Ratio (ROCR), ROC Ratio 100 (ROCR100), Disparity Index, Fisher RSI, RSX, Dynamic Momentum Index, Stochastic CCI, RMI, Derivative Oscillator, Elder Ray, Intraday Momentum Index, QQE |
+| Trend & Directional  | MACD, MACD Fixed (MACDFIX), MACD Extended (MACDEXT), ADX (+DI/-DI), ADXR, Aroon, TRIX, Aroon Oscillator, Vortex, Random Walk Index, Trend Intensity Index, Wave Trend Oscillator, Mass Index, Choppiness Index, Vertical Horizontal Filter, Plus DM, Minus DM, Plus DI, Minus DI, DX, TTM Trend, Trend Strength Index, Qstick, Polarized Fractal Efficiency, Wave PM, Gator Oscillator, Kase Permission Stochastic |
+| Price Oscillators    | PPO, DPO, Coppock, Accelerator Oscillator, Balance of Power, APO, AO Histogram, CFO, Zero-Lag MACD, Elder Impulse, STC, TSF Oscillator, MACD Histogram, PPO Histogram |
+| Volatility & Bands   | ATR, Bollinger Bands, Keltner Channels, Donchian Channels, NATR, StdDev, Ulcer Index, Historical Volatility, Bollinger Bandwidth, %B, True Range, Chaikin Volatility, RVI (Relative Volatility Index), Parkinson Volatility, Garman-Klass Volatility, Rogers-Satchell Volatility, Yang-Zhang Volatility, Volatility Cone |
+| Bands & Channels     | MA Envelope, Acceleration Bands, STARC Bands, ATR Bands, Hurst Channel, LinReg Channel, Standard Error Bands, Double Bollinger Bands, TTM Squeeze, Fractal Chaos Bands, VWAP StdDev Bands, Quartile Bands, Bomar Bands, Median Channel, Projection Bands, Projection Oscillator |
+| Trailing Stops       | Parabolic SAR, Parabolic SAR Extended (SAREXT), SuperTrend, Chandelier Exit, Chande Kroll Stop, ATR Trailing Stop, HiLo Activator, Volty Stop, Yo-Yo Exit, Donchian Channel Stop, Percentage Trailing Stop, Step Trailing Stop, Renko Trailing Stop, Kase DevStop, Elder SafeZone, ATR Ratchet, NRTR, Time-Based Stop, Modified MA Stop |
+| Volume               | OBV, VWAP (cumulative + rolling), ADL, Volume-Price Trend, Chaikin Money Flow, Chaikin Oscillator, Force Index, Ease of Movement, Klinger Volume Oscillator, Volume Oscillator, NVI, PVI, Williams A/D, Anchored VWAP, Demand Index, TSV, VZO, Market Facilitation Index, Volume RSI, Williams Accumulation/Distribution, Twiggs Money Flow, Trade Volume Index, Intraday Intensity Index, Better Volume, Volume-Weighted MACD |
+| Price Statistics     | Typical Price, Median Price, Weighted Close, Linear Regression, Linear Regression Slope, Z-Score, Linear Regression Angle, Variance, Coefficient of Variation, Skewness, Kurtosis, Standard Error, Detrended StdDev, R², Median Absolute Deviation, Autocorrelation, Hurst Exponent, Pearson Correlation, Beta, Pairwise Beta, Pair Spread Z-Score, Lead-Lag Cross-Correlation, Cointegration, Relative Strength A-vs-B, Spearman Correlation, Mid Price, Mid Point, Average Price, Linear Regression Intercept, Time Series Forecast, Rolling Correlation, Rolling Covariance, OU Half-Life, Spread Hurst, Distance SSD, Beta-Neutral Spread, Variance Ratio, Granger Causality, Kalman Hedge Ratio, Spread Bollinger Bands, Spread AR(1) Coefficient, Jarque-Bera, Rolling Min-Max Scaler, Shannon Entropy, Sample Entropy, Kendall Tau |
+| Ehlers / Cycle (DSP) | MAMA, FAMA, Fisher Transform, Inverse Fisher Transform, SuperSmoother, Hilbert Dominant Cycle, Hilbert Phasor, Hilbert DC Phase, Hilbert Trend Mode, Sine Wave, Decycler, Decycler Oscillator, Roofing Filter, Center of Gravity, Cybernetic Cycle, Adaptive Cycle, Empirical Mode Decomposition, Ehlers Stochastic, Instantaneous Trendline, Highpass Filter, Reflex, Trendflex, Correlation Trend Indicator, Adaptive RSI, Universal Oscillator, Adaptive CCI, Bandpass Filter, Even Better Sinewave, Autocorrelation Periodogram |
+| Pivots & S/R         | Classic Pivots, Fibonacci Pivots, Camarilla, Woodie Pivots, DeMark Pivots, Williams Fractals, ZigZag, Central Pivot Range, Murrey Math Lines, Andrews Pitchfork, Volume-Weighted Support/Resistance, Pivot Reversal |
 | DeMark               | TD Setup, TD Sequential, TD DeMarker, TD REI, TD Pressure, TD Combo, TD Countdown, TD Lines, TD Range Projection, TD Differential, TD Open, TD Risk Level |
 | Ichimoku & Charts    | Ichimoku Kinko Hyo (Tenkan, Kijun, Senkou A/B, Chikou), Heikin-Ashi |
 | Alt-Chart Bars       | Renko (box-size bricks), Kagi (reversal-amount lines), Point & Figure (X/O columns) |
@@ -161,7 +153,7 @@ warmup) at [docs.wickra.org](https://docs.wickra.org/Indicators-Overview).
 | Chart Patterns       | Double Top / Bottom, Triple Top / Bottom, Head and Shoulders, Triangle (asc/desc/sym), Wedge (rising/falling), Flag / Pennant, Rectangle / Range, Cup and Handle |
 | Harmonic Patterns    | AB=CD, Gartley, Butterfly, Bat, Crab, Shark, Cypher, Three Drives |
 | Fibonacci            | Fibonacci Retracement, Fibonacci Extension, Fibonacci Projection, Auto-Fibonacci, Golden Pocket, Fibonacci Confluence, Fibonacci Fan, Fibonacci Arcs, Fibonacci Channel, Fibonacci Time Zones |
-| Microstructure       | Order-Book Imbalance (Top-1 / Top-N / Full), Microprice, Quoted Spread, Depth Slope, Signed Volume, Cumulative Volume Delta, Trade Imbalance, Effective Spread, Realized Spread, Kyle's Lambda, Footprint |
+| Microstructure       | Order-Book Imbalance (Top-1 / Top-N / Full), Microprice, Quoted Spread, Depth Slope, Signed Volume, Cumulative Volume Delta, Trade Imbalance, Effective Spread, Realized Spread, Kyle's Lambda, Footprint, Order Flow Imbalance, VPIN, Amihud Illiquidity, Roll Measure |
 | Derivatives          | Funding Rate, Funding Rate Mean, Funding Rate Z-Score, Funding Basis, Open-Interest Delta, OI / Price Divergence, OI-Weighted Price, Long/Short Ratio, Taker Buy/Sell Ratio, Liquidation Features, Term-Structure Basis, Calendar Spread |
 | Market Profile       | Value Area (POC / VAH / VAL), Volume Profile (histogram), TPO Profile, Initial Balance, Opening Range |
 | Market Breadth       | Advance/Decline Line, Advance/Decline Ratio, Advance/Decline Volume Line, McClellan Oscillator, McClellan Summation Index, TRIN / Arms Index, Breadth Thrust, New Highs - New Lows, High-Low Index, Percent Above Moving Average, Up/Down Volume Ratio, Bullish Percent Index, Cumulative Volume Index, Absolute Breadth Index, TICK Index |
@@ -245,9 +237,10 @@ A Python live-trading example using the public `websockets` package lives at
 ```
 wickra/
 ├── crates/
-│   ├── wickra-core/         core engine + all 377 indicators
+│   ├── wickra-core/         core engine + all 467 indicators
 │   ├── wickra/              top-level facade crate (publishes on crates.io) + benches/
-│   └── wickra-data/         CSV reader, tick aggregator, live exchange feeds
+│   ├── wickra-data/         CSV reader, tick aggregator, live exchange feeds
+│   └── wickra-bench/        internal cross-library benchmark harness (not published)
 ├── bindings/
 │   ├── python/              PyO3 + maturin (publishes on PyPI)
 │   ├── node/                napi-rs (publishes on npm)
@@ -261,9 +254,10 @@ wickra/
 └── .github/workflows/       CI and release pipelines
 ```

-Rust benchmarks live in `crates/wickra/benches/`; runnable Rust examples live
-in the workspace member crate at `examples/rust/`. There is no top-level
-`benches/` directory.
+Wickra's own regression benchmarks live in `crates/wickra/benches/`; the
+cross-library comparison against kand, ta-rs and yata lives in the internal
+`crates/wickra-bench/` crate. Runnable Rust examples live in the workspace member
+crate at `examples/rust/`. There is no top-level `benches/` directory.

 ## Building everything from source

@@ -271,7 +265,8 @@ in the workspace member crate at `examples/rust/`. There is no top-level
 # Rust core + tests
 cargo test --workspace
 cargo clippy --workspace --all-targets -- -D warnings
-cargo bench -p wickra
+cargo bench -p wickra           # Wickra's own regression benchmarks
+cargo bench -p wickra-bench     # cross-library comparison (kand, ta-rs, yata)

 # Python binding (requires Rust toolchain + maturin)
 cd bindings/python
@@ -371,3 +366,10 @@ The library is provided **as is**, without warranty of any kind; see
 <p align="center">
  If Wickra saved you time, the cheapest way to say thanks is to ⭐ the repo.
 </p>
+
+<p align="center">
+  <a href="https://star-history.com/#wickra-lib/wickra&Date">
+    <img alt="Wickra star history" width="640"
+         src="https://api.star-history.com/svg?repos=wickra-lib/wickra&type=Date&theme=dark">
+  </a>
+</p>
@@ -28,6 +28,52 @@ function num(v) {
 // --- Scalar indicators: update(value) vs batch(prices) ---

 const scalarFactories = {
+  AUTOCORRPGRAM: () => new wickra.AUTOCORRPGRAM(10, 48),
+  EVENBETTERSINE: () => new wickra.EVENBETTERSINE(40, 10),
+  BANDPASS: () => new wickra.BANDPASS(20, 0.3),
+  UNIVERSALOSC: () => new wickra.UNIVERSALOSC(20),
+  ADAPTIVERSI: () => new wickra.ADAPTIVERSI(14),
+  CTI: () => new wickra.CTI(20),
+  TRENDFLEX: () => new wickra.TRENDFLEX(20),
+  REFLEX: () => new wickra.REFLEX(20),
+  HIGHPASS: () => new wickra.HIGHPASS(48),
+  SAMPLEENT: () => new wickra.SAMPLEENT(20, 2, 0.2),
+  SHANNONENT: () => new wickra.SHANNONENT(20, 8),
+  ROLLINGMINMAX: () => new wickra.ROLLINGMINMAX(20),
+  JARQUEBERA: () => new wickra.JARQUEBERA(20),
+  BipowerVariation: () => new wickra.BipowerVariation(20),
+  VolatilityOfVolatility: () => new wickra.VolatilityOfVolatility(20, 20),
+  Garch11: () => new wickra.Garch11(0.000002, 0.1, 0.88),
+  EwmaVolatility: () => new wickra.EwmaVolatility(0.94),
+  PpoHistogram: () => new wickra.PpoHistogram(3, 6, 3),
+  MacdHistogram: () => new wickra.MacdHistogram(3, 6, 3),
+  TsfOscillator: () => new wickra.TsfOscillator(3),
+  WAVE_PM: () => new wickra.WAVE_PM(32, 3),
+  POLARIZED_FRACTAL_EFFICIENCY: () => new wickra.POLARIZED_FRACTAL_EFFICIENCY(10, 5),
+  TREND_STRENGTH_INDEX: () => new wickra.TREND_STRENGTH_INDEX(20),
+  DerivativeOscillator: () => new wickra.DerivativeOscillator(14, 5, 3, 9),
+  RMI: () => new wickra.RMI(14, 5),
+  DynamicMomentumIndex: () => new wickra.DynamicMomentumIndex(14),
+  RSX: () => new wickra.RSX(14),
+  FisherRSI: () => new wickra.FisherRSI(14),
+  DisparityIndex: () => new wickra.DisparityIndex(14),
+  HoltWinters: () => new wickra.HoltWinters(0.2, 0.1),
+  GD: () => new wickra.GD(5, 0.7),
+  AdaptiveLaguerre: () => new wickra.AdaptiveLaguerre(13),
+  MedianMA: () => new wickra.MedianMA(14),
+  EHMA: () => new wickra.EHMA(9),
+  GMA: () => new wickra.GMA(14),
+  SWMA: () => new wickra.SWMA(14),
+  Expectancy: () => new wickra.Expectancy(20),
+  WinRate: () => new wickra.WinRate(20),
+  RegimeLabel: () => new wickra.RegimeLabel(5, 20),
+  JumpIndicator: () => new wickra.JumpIndicator(20, 3.0),
+  TrendLabel: () => new wickra.TrendLabel(10),
+  RollingQuantile: () => new wickra.RollingQuantile(20, 0.5),
+  RollingPercentileRank: () => new wickra.RollingPercentileRank(14),
+  RollingIqr: () => new wickra.RollingIqr(14),
+  RealizedVolatility: () => new wickra.RealizedVolatility(20),
+  LogReturn: () => new wickra.LogReturn(1),
  TSF: () => new wickra.TSF(14),
  LINEARREG_INTERCEPT: () => new wickra.LINEARREG_INTERCEPT(14),
  ROCR100: () => new wickra.ROCR100(10),
@@ -313,6 +359,25 @@ const candleScalar = {
  Shark: { make: () => new wickra.Shark(), step: (ind, i) => ind.update(open[i], high[i], low[i], close[i]), batch: (ind) => ind.batch(open, high, low, close) },
  Cypher: { make: () => new wickra.Cypher(), step: (ind, i) => ind.update(open[i], high[i], low[i], close[i]), batch: (ind) => ind.batch(open, high, low, close) },
  ThreeDrives: { make: () => new wickra.ThreeDrives(), step: (ind, i) => ind.update(open[i], high[i], low[i], close[i]), batch: (ind) => ind.batch(open, high, low, close) },
+  CloseVsOpen: { make: () => new wickra.CloseVsOpen(), step: (ind, i) => ind.update(open[i], high[i], low[i], close[i]), batch: (ind) => ind.batch(open, high, low, close) },
+  BodySizePct: { make: () => new wickra.BodySizePct(), step: (ind, i) => ind.update(open[i], high[i], low[i], close[i]), batch: (ind) => ind.batch(open, high, low, close) },
+  WickRatio: { make: () => new wickra.WickRatio(), step: (ind, i) => ind.update(open[i], high[i], low[i], close[i]), batch: (ind) => ind.batch(open, high, low, close) },
+  HighLowRange: { make: () => new wickra.HighLowRange(), step: (ind, i) => ind.update(open[i], high[i], low[i], close[i]), batch: (ind) => ind.batch(open, high, low, close) },
+  StochasticCCI: { make: () => new wickra.StochasticCCI(14), step: (ind, i) => ind.update(high[i], low[i], close[i]), batch: (ind) => ind.batch(high, low, close) },
+  IMI: { make: () => new wickra.IMI(14), step: (ind, i) => ind.update(open[i], high[i], low[i], close[i]), batch: (ind) => ind.batch(open, high, low, close) },
+  TTM_TREND: { make: () => new wickra.TTM_TREND(6), step: (ind, i) => ind.update(high[i], low[i], close[i]), batch: (ind) => ind.batch(high, low, close) },
+  Qstick: { make: () => new wickra.Qstick(10), step: (ind, i) => ind.update(open[i], close[i]), batch: (ind) => ind.batch(open, close) },
+  VolatilityRatio: { make: () => new wickra.VolatilityRatio(14), step: (ind, i) => ind.update(high[i], low[i], close[i]), batch: (ind) => ind.batch(high, low, close) },
+  ProjectionOscillator: { make: () => new wickra.ProjectionOscillator(14), step: (ind, i) => ind.update(high[i], low[i], close[i]), batch: (ind) => ind.batch(high, low, close) },
+  TimeBasedStop: { make: () => new wickra.TimeBasedStop(5), step: (ind, i) => ind.update(high[i], low[i], close[i]), batch: (ind) => ind.batch(high, low, close) },
+  VolumeRsi: { make: () => new wickra.VolumeRsi(14), step: (ind, i) => ind.update(close[i], volume[i]), batch: (ind) => ind.batch(close, volume) },
+  Wad: { make: () => new wickra.Wad(), step: (ind, i) => ind.update(high[i], low[i], close[i]), batch: (ind) => ind.batch(high, low, close) },
+  TwiggsMoneyFlow: { make: () => new wickra.TwiggsMoneyFlow(21), step: (ind, i) => ind.update(high[i], low[i], close[i], volume[i]), batch: (ind) => ind.batch(high, low, close, volume) },
+  TradeVolumeIndex: { make: () => new wickra.TradeVolumeIndex(0.25), step: (ind, i) => ind.update(close[i], volume[i]), batch: (ind) => ind.batch(close, volume) },
+  IntradayIntensity: { make: () => new wickra.IntradayIntensity(), step: (ind, i) => ind.update(high[i], low[i], close[i], volume[i]), batch: (ind) => ind.batch(high, low, close, volume) },
+  BetterVolume: { make: () => new wickra.BetterVolume(14), step: (ind, i) => ind.update(high[i], low[i], close[i], volume[i]), batch: (ind) => ind.batch(high, low, close, volume) },
+  ADAPTIVECCI: { make: () => new wickra.ADAPTIVECCI(20), step: (ind, i) => ind.update(high[i], low[i], close[i]), batch: (ind) => ind.batch(high, low, close) },
+  PivotReversal: { make: () => new wickra.PivotReversal(1, 1), step: (ind, i) => ind.update(high[i], low[i], close[i]), batch: (ind) => ind.batch(high, low, close) },
 };

 for (const [name, d] of Object.entries(candleScalar)) {
@@ -395,6 +460,25 @@ const multi = {
  FibArcs: { make: () => new wickra.FibArcs(), fields: ['arc382', 'arc500', 'arc618'], step: (ind, i) => ind.update(high[i], low[i]), batch: (ind) => ind.batch(high, low) },
  FibChannel: { make: () => new wickra.FibChannel(), fields: ['base', 'level618', 'level1000', 'level1618'], step: (ind, i) => ind.update(high[i], low[i]), batch: (ind) => ind.batch(high, low) },
  FibTimeZones: { make: () => new wickra.FibTimeZones(), fields: ['onZone', 'barsToNext'], step: (ind, i) => ind.update(high[i], low[i]), batch: (ind) => ind.batch(high, low) },
+  ElderRay: { make: () => new wickra.ElderRay(13), fields: ['bullPower', 'bearPower'], step: (ind, i) => ind.update(high[i], low[i], close[i]), batch: (ind) => ind.batch(high, low, close) },
+  QQE: { make: () => new wickra.QQE(14, 5, 4.236), fields: ['rsiMa', 'trailingLine'], step: (ind, i) => ind.update(close[i]), batch: (ind) => ind.batch(close) },
+  GatorOscillator: { make: () => new wickra.GatorOscillator(13, 8, 5), fields: ['upper', 'lower'], step: (ind, i) => ind.update(high[i], low[i], close[i]), batch: (ind) => ind.batch(high, low, close) },
+  KasePermissionStochastic: { make: () => new wickra.KasePermissionStochastic(9, 3), fields: ['fast', 'slow'], step: (ind, i) => ind.update(high[i], low[i], close[i]), batch: (ind) => ind.batch(high, low, close) },
+  VolatilityCone: { make: () => new wickra.VolatilityCone(20, 60), fields: ['current', 'min', 'median', 'max', 'percentile'], step: (ind, i) => ind.update(high[i], low[i], close[i]), batch: (ind) => ind.batch(high, low, close) },
+  QuartileBands: { make: () => new wickra.QuartileBands(4), fields: ['upper', 'middle', 'lower'], step: (ind, i) => ind.update(close[i]), batch: (ind) => ind.batch(close) },
+  BomarBands: { make: () => new wickra.BomarBands(4, 0.85), fields: ['upper', 'middle', 'lower'], step: (ind, i) => ind.update(close[i]), batch: (ind) => ind.batch(close) },
+  MedianChannel: { make: () => new wickra.MedianChannel(5, 2.0), fields: ['upper', 'middle', 'lower'], step: (ind, i) => ind.update(close[i]), batch: (ind) => ind.batch(close) },
+  ProjectionBands: { make: () => new wickra.ProjectionBands(3), fields: ['upper', 'middle', 'lower'], step: (ind, i) => ind.update(high[i], low[i]), batch: (ind) => ind.batch(high, low) },
+  KaseDevStop: { make: () => new wickra.KaseDevStop(3, 1.0), fields: ['value', 'direction'], step: (ind, i) => ind.update(high[i], low[i], close[i]), batch: (ind) => ind.batch(high, low, close) },
+  ElderSafeZone: { make: () => new wickra.ElderSafeZone(14, 2.0), fields: ['value', 'direction'], step: (ind, i) => ind.update(high[i], low[i], close[i]), batch: (ind) => ind.batch(high, low, close) },
+  AtrRatchet: { make: () => new wickra.AtrRatchet(14, 4.0, 0.1), fields: ['value', 'direction'], step: (ind, i) => ind.update(high[i], low[i], close[i]), batch: (ind) => ind.batch(high, low, close) },
+  Nrtr: { make: () => new wickra.Nrtr(2.0), fields: ['value', 'direction'], step: (ind, i) => ind.update(high[i], low[i], close[i]), batch: (ind) => ind.batch(high, low, close) },
+  ModifiedMaStop: { make: () => new wickra.ModifiedMaStop(14), fields: ['value', 'direction'], step: (ind, i) => ind.update(high[i], low[i], close[i]), batch: (ind) => ind.batch(high, low, close) },
+  VolumeWeightedMacd: { make: () => new wickra.VolumeWeightedMacd(12, 26, 9), fields: ['macd', 'signal', 'histogram'], step: (ind, i) => ind.update(close[i], volume[i]), batch: (ind) => ind.batch(close, volume) },
+  CentralPivotRange: { make: () => new wickra.CentralPivotRange(), fields: ['pivot', 'tc', 'bc'], step: (ind, i) => ind.update(high[i], low[i], close[i]), batch: (ind) => ind.batch(high, low, close) },
+  MurreyMathLines: { make: () => new wickra.MurreyMathLines(4), fields: ['mm8_8', 'mm7_8', 'mm6_8', 'mm5_8', 'mm4_8', 'mm3_8', 'mm2_8', 'mm1_8', 'mm0_8'], step: (ind, i) => ind.update(high[i], low[i]), batch: (ind) => ind.batch(high, low) },
+  AndrewsPitchfork: { make: () => new wickra.AndrewsPitchfork(2), fields: ['median', 'upper', 'lower'], step: (ind, i) => ind.update(high[i], low[i]), batch: (ind) => ind.batch(high, low) },
+  VolumeWeightedSr: { make: () => new wickra.VolumeWeightedSr(3), fields: ['support', 'resistance'], step: (ind, i) => ind.update(high[i], low[i], volume[i]), batch: (ind) => ind.batch(high, low, volume) },
 };

 for (const [name, d] of Object.entries(multi)) {
@@ -563,6 +647,8 @@ const pairFactories = {
  BetaNeutralSpread: () => new wickra.BetaNeutralSpread(20),
  VarianceRatio: () => new wickra.VarianceRatio(60, 2),
  GrangerCausality: () => new wickra.GrangerCausality(60, 1),
+  SpreadAr1Coefficient: () => new wickra.SpreadAr1Coefficient(40),
+  KendallTau: () => new wickra.KendallTau(20),
 };

 for (const [name, make] of Object.entries(pairFactories)) {
@@ -1126,6 +1212,57 @@ test('trade-flow rejects bad input', () => {
  assert.throws(() => new wickra.SignedVolume().update(100, -1, true));
 });

+test('order-flow imbalance reference + streaming matches batch', () => {
+  // Rising bid (px up, size 6) with an unchanged ask -> +6 flow.
+  const ofi = new wickra.OrderFlowImbalance(1);
+  assert.equal(ofi.update([100], [5], [101], [4]), null); // seeds the reference
+  assert.ok(Math.abs(ofi.update([100.5], [6], [101], [4]) - 6.0) < 1e-12);
+  const snaps = Array.from({ length: 30 }, (_, i) => ({
+    bidPx: [100 + Math.sin(i * 0.3)],
+    bidSz: [5 + Math.abs(Math.cos(i * 0.5))],
+    askPx: [101 + Math.sin(i * 0.3)],
+    askSz: [4 + Math.abs(Math.sin(i * 0.4))],
+  }));
+  const batch = new wickra.OrderFlowImbalance(10).batch(snaps);
+  const streamer = new wickra.OrderFlowImbalance(10);
+  assert.equal(batch.length, snaps.length);
+  for (let i = 0; i < snaps.length; i++) {
+    const s = streamer.update(snaps[i].bidPx, snaps[i].bidSz, snaps[i].askPx, snaps[i].askSz);
+    assert.ok((Number.isNaN(batch[i]) && s === null) || Math.abs(s - batch[i]) < 1e-9, `mismatch at ${i}`);
+  }
+});
+
+test('vpin / amihud / roll reference + streaming matches batch', () => {
+  // VPIN: two pure-buy buckets of size 10 -> imbalance == size -> 1.
+  const v = new wickra.Vpin(10, 2);
+  let last;
+  for (let i = 0; i < 4; i++) last = v.update(100, 5, true);
+  assert.equal(last, 1.0);
+  // Amihud(1): |ln(101/100)| / (101 * 10).
+  const a = new wickra.AmihudIlliquidity(1);
+  assert.equal(a.update(100, 10, true), null);
+  assert.ok(Math.abs(a.update(101, 10, true) - Math.abs(Math.log(101 / 100)) / (101 * 10)) < 1e-15);
+  // Roll(6): a clean bid-ask bounce of ±1 implies a spread of 2.
+  const r = new wickra.RollMeasure(6);
+  let roll = null;
+  for (let i = 0; i < 20; i++) roll = r.update(i % 2 === 0 ? 100 : 101, 1, true);
+  assert.ok(Math.abs(roll - 2.0) < 1e-12);
+  // Streaming-vs-batch for the three trade-input indicators.
+  const n = 40;
+  const price = Array.from({ length: n }, (_, i) => 100 + Math.sin(i * 0.25) * 4);
+  const size = Array.from({ length: n }, (_, i) => 1 + (i % 5));
+  const isBuy = Array.from({ length: n }, (_, i) => i % 2 === 0);
+  for (const make of [() => new wickra.Vpin(8, 5), () => new wickra.AmihudIlliquidity(14), () => new wickra.RollMeasure(14)]) {
+    const batch = make().batch(price, size, isBuy);
+    const streamer = make();
+    assert.equal(batch.length, n);
+    for (let i = 0; i < n; i++) {
+      const s = streamer.update(price[i], size[i], isBuy[i]);
+      assert.ok((Number.isNaN(batch[i]) && s === null) || Math.abs(s - batch[i]) < 1e-9, `mismatch at ${i}`);
+    }
+  }
+});
+
 test('price-impact indicators reference values', () => {
  // Buy at 100.05 vs mid 100.0: 2 * (100.05 - 100) / 100 * 10000 = 10 bps.
  assert.ok(Math.abs(new wickra.EffectiveSpread().update(100.05, 1, true, 100.0) - 10.0) < 1e-9);
@@ -1,6 +1,6 @@
 {
  "name": "wickra-darwin-arm64",
-  "version": "0.5.3",
+  "version": "0.6.6",
  "description": "Native binding for wickra (macOS Apple Silicon). Installed automatically as an optional dependency of wickra on matching platforms.",
  "main": "wickra.darwin-arm64.node",
  "files": [
@@ -1,6 +1,6 @@
 {
  "name": "wickra-darwin-x64",
-  "version": "0.5.3",
+  "version": "0.6.6",
  "description": "Native binding for wickra (macOS Intel). Installed automatically as an optional dependency of wickra on matching platforms.",
  "main": "wickra.darwin-x64.node",
  "files": [
@@ -1,6 +1,6 @@
 {
  "name": "wickra-linux-arm64-gnu",
-  "version": "0.5.3",
+  "version": "0.6.6",
  "description": "Native binding for wickra (linux arm64 GNU). Installed automatically as an optional dependency of wickra on matching platforms.",
  "main": "wickra.linux-arm64-gnu.node",
  "files": [
@@ -1,6 +1,6 @@
 {
  "name": "wickra-linux-x64-gnu",
-  "version": "0.5.3",
+  "version": "0.6.6",
  "description": "Native binding for wickra (linux x64 GNU). Installed automatically as an optional dependency of wickra on matching platforms.",
  "main": "wickra.linux-x64-gnu.node",
  "files": [
@@ -1,6 +1,6 @@
 {
  "name": "wickra-win32-arm64-msvc",
-  "version": "0.5.3",
+  "version": "0.6.6",
  "description": "Native binding for wickra (Windows arm64 MSVC). Installed automatically as an optional dependency of wickra on matching platforms.",
  "main": "wickra.win32-arm64-msvc.node",
  "files": [
@@ -1,6 +1,6 @@
 {
  "name": "wickra-win32-x64-msvc",
-  "version": "0.5.3",
+  "version": "0.6.6",
  "description": "Native binding for wickra (Windows x64 MSVC). Installed automatically as an optional dependency of wickra on matching platforms.",
  "main": "wickra.win32-x64-msvc.node",
  "files": [
@@ -1,12 +1,12 @@
 {
  "name": "wickra",
-  "version": "0.5.3",
+  "version": "0.6.6",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "wickra",
-      "version": "0.5.3",
+      "version": "0.6.6",
      "license": "MIT OR Apache-2.0",
      "devDependencies": {
        "@napi-rs/cli": "^2.18.0"
@@ -15,12 +15,12 @@
        "node": ">= 18"
      },
      "optionalDependencies": {
-        "wickra-darwin-arm64": "0.5.3",
-        "wickra-darwin-x64": "0.5.3",
-        "wickra-linux-arm64-gnu": "0.5.3",
-        "wickra-linux-x64-gnu": "0.5.3",
-        "wickra-win32-arm64-msvc": "0.5.3",
-        "wickra-win32-x64-msvc": "0.5.3"
+        "wickra-darwin-arm64": "0.6.6",
+        "wickra-darwin-x64": "0.6.6",
+        "wickra-linux-arm64-gnu": "0.6.6",
+        "wickra-linux-x64-gnu": "0.6.6",
+        "wickra-win32-arm64-msvc": "0.6.6",
+        "wickra-win32-x64-msvc": "0.6.6"
      }
    },
    "node_modules/@napi-rs/cli": {
@@ -41,8 +41,8 @@
      }
    },
    "node_modules/wickra-darwin-arm64": {
-      "version": "0.5.3",
-      "resolved": "https://registry.npmjs.org/wickra-darwin-arm64/-/wickra-darwin-arm64-0.5.3.tgz",
+      "version": "0.6.6",
+      "resolved": "https://registry.npmjs.org/wickra-darwin-arm64/-/wickra-darwin-arm64-0.6.6.tgz",
      "integrity": "sha512-4eZiBR/yGUdr4nzhEUFy2i69XgNx64iI2ax/LPamsThgylC0KpHOZKK19QzJ2d9KbK4C8nMjME5FLuR+4GNEwQ==",
      "cpu": [
        "arm64"
@@ -57,8 +57,8 @@
      }
    },
    "node_modules/wickra-darwin-x64": {
-      "version": "0.5.3",
-      "resolved": "https://registry.npmjs.org/wickra-darwin-x64/-/wickra-darwin-x64-0.5.3.tgz",
+      "version": "0.6.6",
+      "resolved": "https://registry.npmjs.org/wickra-darwin-x64/-/wickra-darwin-x64-0.6.6.tgz",
      "integrity": "sha512-6hf8zI3QPjTFp4zCpmgUwDvNtu6jHqNUHKD5e55POo0CgA52HkpyxSPtVm8TGTIZDI7kPjlbOdBM8CJ76mmXwA==",
      "cpu": [
        "x64"
@@ -73,8 +73,8 @@
      }
    },
    "node_modules/wickra-linux-arm64-gnu": {
-      "version": "0.5.3",
-      "resolved": "https://registry.npmjs.org/wickra-linux-arm64-gnu/-/wickra-linux-arm64-gnu-0.5.3.tgz",
+      "version": "0.6.6",
+      "resolved": "https://registry.npmjs.org/wickra-linux-arm64-gnu/-/wickra-linux-arm64-gnu-0.6.6.tgz",
      "integrity": "sha512-kSe6y0xBMSiqdPLXNjwop5WZdHtvdBNKSEBCwZ4hFq33p4apW25/wrlzv9/oDuyD4kuPabJEhCCnFOplh58CUg==",
      "cpu": [
        "arm64"
@@ -89,8 +89,8 @@
      }
    },
    "node_modules/wickra-linux-x64-gnu": {
-      "version": "0.5.3",
-      "resolved": "https://registry.npmjs.org/wickra-linux-x64-gnu/-/wickra-linux-x64-gnu-0.5.3.tgz",
+      "version": "0.6.6",
+      "resolved": "https://registry.npmjs.org/wickra-linux-x64-gnu/-/wickra-linux-x64-gnu-0.6.6.tgz",
      "integrity": "sha512-tWBWS4qz7hxM4xnpFb59bhf6TaLwXq0Z3jEa/2l7r8PiHA94g8r8S53NRMiT+4yiL5hSWe/nUiC/YXdRrhEZ4g==",
      "cpu": [
        "x64"
@@ -105,8 +105,8 @@
      }
    },
    "node_modules/wickra-win32-arm64-msvc": {
-      "version": "0.5.3",
-      "resolved": "https://registry.npmjs.org/wickra-win32-arm64-msvc/-/wickra-win32-arm64-msvc-0.5.3.tgz",
+      "version": "0.6.6",
+      "resolved": "https://registry.npmjs.org/wickra-win32-arm64-msvc/-/wickra-win32-arm64-msvc-0.6.6.tgz",
      "integrity": "sha512-EXIckHxAtF75PUGDKRzXyqMe9ldP0JjSdu68WFN6iJfp+McYrGu6h40TEJlQ/oUEIoPqiZB/xhVyo/el5Lg7zw==",
      "cpu": [
        "arm64"
@@ -121,8 +121,8 @@
      }
    },
    "node_modules/wickra-win32-x64-msvc": {
-      "version": "0.5.3",
-      "resolved": "https://registry.npmjs.org/wickra-win32-x64-msvc/-/wickra-win32-x64-msvc-0.5.3.tgz",
+      "version": "0.6.6",
+      "resolved": "https://registry.npmjs.org/wickra-win32-x64-msvc/-/wickra-win32-x64-msvc-0.6.6.tgz",
      "integrity": "sha512-Yfsqq1Xwp6hdxMyLze411vNdo7BDwI6+lPSe7A9XdqyPecNDbtKwYLpsal2r8EHbNzqM+R8XnuRtUaEQS5VlUQ==",
      "cpu": [
        "x64"
@@ -1,6 +1,6 @@
 {
  "name": "wickra",
-  "version": "0.5.3",
+  "version": "0.6.6",
  "description": "Streaming-first technical indicators: incremental, fast, install-free. Node bindings powered by Rust.",
  "author": "kingchenc <support@wickra.org>",
  "main": "index.js",
@@ -47,12 +47,12 @@
    "node": ">= 18"
  },
  "optionalDependencies": {
-    "wickra-linux-x64-gnu": "0.5.3",
-    "wickra-linux-arm64-gnu": "0.5.3",
-    "wickra-darwin-x64": "0.5.3",
-    "wickra-darwin-arm64": "0.5.3",
-    "wickra-win32-x64-msvc": "0.5.3",
-    "wickra-win32-arm64-msvc": "0.5.3"
+    "wickra-linux-x64-gnu": "0.6.6",
+    "wickra-linux-arm64-gnu": "0.6.6",
+    "wickra-darwin-x64": "0.6.6",
+    "wickra-darwin-arm64": "0.6.6",
+    "wickra-win32-x64-msvc": "0.6.6",
+    "wickra-win32-arm64-msvc": "0.6.6"
  },
  "scripts": {
    "build": "napi build --platform --release",
@@ -49,6 +49,7 @@ TALIB = _try_import("talib")
 PANDAS_TA = _try_import("pandas_ta")
 TALIPP = _try_import("talipp.indicators") or _try_import("talipp")
 FINTA = _try_import("finta")
+TULIPY = _try_import("tulipy")
 PD = _try_import("pandas")
 import wickra as WICKRA  # noqa: E402  -- the library under test must be importable

@@ -71,13 +72,23 @@ class Sample:
        return (self.seconds / self.iterations) * 1_000_000


-def time_call(fn: Callable[[], None], iterations: int) -> float:
-    """Time ``fn`` over ``iterations`` calls, returning total wall seconds."""
+def time_call(fn: Callable[[], None], iterations: int, rounds: int = 5) -> float:
+    """Time ``fn`` over ``iterations`` calls per round, across ``rounds`` rounds.
+
+    Returns the *median* round's wall seconds for one round of ``iterations``
+    calls. Taking the median across several rounds damps the OS scheduling and
+    GC jitter that a single timing pass would otherwise bake into the result,
+    so the per-iteration figure is stable run-to-run. Callers keep dividing the
+    return value by ``iterations``.
+    """
    fn()  # one warmup call to populate caches
-    start = time.perf_counter()
-    for _ in range(iterations):
-        fn()
-    return time.perf_counter() - start
+    rounds_s: List[float] = []
+    for _ in range(rounds):
+        start = time.perf_counter()
+        for _ in range(iterations):
+            fn()
+        rounds_s.append(time.perf_counter() - start)
+    return statistics.median(rounds_s)


 def gen_prices(n: int, seed: int = 0xC0FFEE) -> np.ndarray:
@@ -275,6 +286,34 @@ def talipp_bollinger_batch(prices: np.ndarray) -> Optional[Callable[[], None]]:
    return lambda: BB(period=20, std_dev_mult=2.0, input_values=list(prices))


+# tulipy wraps the C "Tulip Indicators" library; it takes contiguous float64
+# arrays and indicator options as positional arguments.
+
+
+def tulipy_sma_batch(prices: np.ndarray) -> Optional[Callable[[], None]]:
+    return None if TULIPY is None else (lambda: TULIPY.sma(prices, 20))
+
+
+def tulipy_ema_batch(prices: np.ndarray) -> Optional[Callable[[], None]]:
+    return None if TULIPY is None else (lambda: TULIPY.ema(prices, 20))
+
+
+def tulipy_rsi_batch(prices: np.ndarray) -> Optional[Callable[[], None]]:
+    return None if TULIPY is None else (lambda: TULIPY.rsi(prices, 14))
+
+
+def tulipy_macd_batch(prices: np.ndarray) -> Optional[Callable[[], None]]:
+    return None if TULIPY is None else (lambda: TULIPY.macd(prices, 12, 26, 9))
+
+
+def tulipy_bollinger_batch(prices: np.ndarray) -> Optional[Callable[[], None]]:
+    return None if TULIPY is None else (lambda: TULIPY.bbands(prices, 20, 2.0))
+
+
+def tulipy_atr_batch(high: np.ndarray, low: np.ndarray, close: np.ndarray) -> Optional[Callable[[], None]]:
+    return None if TULIPY is None else (lambda: TULIPY.atr(high, low, close, 14))
+
+
 # --------------------------------------------------------------------------- #
 # Streaming scenario: per-tick latency
 # --------------------------------------------------------------------------- #
@@ -329,6 +368,260 @@ def talipp_rsi_streaming(seed: np.ndarray, live: np.ndarray) -> Optional[Callabl
    return run


+# Scalar streaming peers: Wickra and talipp both update incrementally in O(1),
+# so this is the like-for-like per-tick comparison (batch-only libs are covered
+# by the batch tables and the recompute contrast on RSI above).
+
+
+def wickra_sma_streaming(seed: np.ndarray, live: np.ndarray) -> Callable[[], None]:
+    def run() -> None:
+        sma = WICKRA.SMA(20)
+        sma.batch(seed)
+        for p in live:
+            sma.update(float(p))
+
+    return run
+
+
+def talipp_sma_streaming(seed: np.ndarray, live: np.ndarray) -> Optional[Callable[[], None]]:
+    if TALIPP is None:
+        return None
+    from talipp.indicators import SMA  # type: ignore
+
+    def run() -> None:
+        sma = SMA(period=20, input_values=list(seed))
+        for p in live:
+            sma.add(float(p))
+
+    return run
+
+
+def wickra_ema_streaming(seed: np.ndarray, live: np.ndarray) -> Callable[[], None]:
+    def run() -> None:
+        ema = WICKRA.EMA(20)
+        ema.batch(seed)
+        for p in live:
+            ema.update(float(p))
+
+    return run
+
+
+def talipp_ema_streaming(seed: np.ndarray, live: np.ndarray) -> Optional[Callable[[], None]]:
+    if TALIPP is None:
+        return None
+    from talipp.indicators import EMA  # type: ignore
+
+    def run() -> None:
+        ema = EMA(period=20, input_values=list(seed))
+        for p in live:
+            ema.add(float(p))
+
+    return run
+
+
+def wickra_macd_streaming(seed: np.ndarray, live: np.ndarray) -> Callable[[], None]:
+    def run() -> None:
+        macd = WICKRA.MACD()
+        macd.batch(seed)
+        for p in live:
+            macd.update(float(p))
+
+    return run
+
+
+def talipp_macd_streaming(seed: np.ndarray, live: np.ndarray) -> Optional[Callable[[], None]]:
+    if TALIPP is None:
+        return None
+    from talipp.indicators import MACD  # type: ignore
+
+    def run() -> None:
+        macd = MACD(
+            fast_period=12, slow_period=26, signal_period=9, input_values=list(seed)
+        )
+        for p in live:
+            macd.add(float(p))
+
+    return run
+
+
+def wickra_bollinger_streaming(seed: np.ndarray, live: np.ndarray) -> Callable[[], None]:
+    def run() -> None:
+        bb = WICKRA.BollingerBands(20, 2.0)
+        bb.batch(seed)
+        for p in live:
+            bb.update(float(p))
+
+    return run
+
+
+def talipp_bollinger_streaming(seed: np.ndarray, live: np.ndarray) -> Optional[Callable[[], None]]:
+    if TALIPP is None:
+        return None
+    from talipp.indicators import BB  # type: ignore
+
+    def run() -> None:
+        bb = BB(period=20, std_dev_mult=2.0, input_values=list(seed))
+        for p in live:
+            bb.add(float(p))
+
+    return run
+
+
+# Recompute streaming peers: batch-only libraries have no incremental API, so
+# the only honest way to drive them tick-by-tick is to re-run the full batch
+# over the grown history on every new price. These runners expose exactly that
+# cost — the gap Wickra's O(1) update closes.
+
+
+def _talib_recompute_streaming(seed, live, fn):
+    def run() -> None:
+        history = list(seed)
+        for p in live:
+            history.append(float(p))
+            fn(np.asarray(history))
+
+    return run
+
+
+def _pandas_ta_recompute_streaming(seed, live, fn):
+    def run() -> None:
+        history = list(seed)
+        for p in live:
+            history.append(float(p))
+            fn(PD.Series(history))
+
+    return run
+
+
+def _tulipy_recompute_streaming(seed, live, fn):
+    def run() -> None:
+        history = list(seed)
+        for p in live:
+            history.append(float(p))
+            fn(np.asarray(history, dtype=np.float64))
+
+    return run
+
+
+def _finta_recompute_streaming(seed, live, fn):
+    def run() -> None:
+        history = list(seed)
+        for p in live:
+            history.append(float(p))
+            arr = np.asarray(history)
+            fn(PD.DataFrame({"open": arr, "high": arr, "low": arr, "close": arr, "volume": np.ones_like(arr)}))
+
+    return run
+
+
+def talib_sma_streaming(seed, live):
+    if TALIB is None:
+        return None
+    return _talib_recompute_streaming(seed, live, lambda a: TALIB.SMA(a, timeperiod=20))
+
+
+def pandas_ta_sma_streaming(seed, live):
+    if PANDAS_TA is None or PD is None:
+        return None
+    return _pandas_ta_recompute_streaming(seed, live, lambda s: PANDAS_TA.sma(s, length=20))
+
+
+def tulipy_sma_streaming(seed, live):
+    if TULIPY is None:
+        return None
+    return _tulipy_recompute_streaming(seed, live, lambda a: TULIPY.sma(a, 20))
+
+
+def finta_sma_streaming(seed, live):
+    if FINTA is None or PD is None:
+        return None
+    return _finta_recompute_streaming(seed, live, lambda df: FINTA.TA.SMA(df, period=20))
+
+
+def talib_ema_streaming(seed, live):
+    if TALIB is None:
+        return None
+    return _talib_recompute_streaming(seed, live, lambda a: TALIB.EMA(a, timeperiod=20))
+
+
+def pandas_ta_ema_streaming(seed, live):
+    if PANDAS_TA is None or PD is None:
+        return None
+    return _pandas_ta_recompute_streaming(seed, live, lambda s: PANDAS_TA.ema(s, length=20))
+
+
+def tulipy_ema_streaming(seed, live):
+    if TULIPY is None:
+        return None
+    return _tulipy_recompute_streaming(seed, live, lambda a: TULIPY.ema(a, 20))
+
+
+def finta_ema_streaming(seed, live):
+    if FINTA is None or PD is None:
+        return None
+    return _finta_recompute_streaming(seed, live, lambda df: FINTA.TA.EMA(df, period=20))
+
+
+def tulipy_rsi_streaming(seed, live):
+    if TULIPY is None:
+        return None
+    return _tulipy_recompute_streaming(seed, live, lambda a: TULIPY.rsi(a, 14))
+
+
+def finta_rsi_streaming(seed, live):
+    if FINTA is None or PD is None:
+        return None
+    return _finta_recompute_streaming(seed, live, lambda df: FINTA.TA.RSI(df, period=14))
+
+
+def talib_macd_streaming(seed, live):
+    if TALIB is None:
+        return None
+    return _talib_recompute_streaming(seed, live, lambda a: TALIB.MACD(a))
+
+
+def pandas_ta_macd_streaming(seed, live):
+    if PANDAS_TA is None or PD is None:
+        return None
+    return _pandas_ta_recompute_streaming(seed, live, lambda s: PANDAS_TA.macd(s))
+
+
+def tulipy_macd_streaming(seed, live):
+    if TULIPY is None:
+        return None
+    return _tulipy_recompute_streaming(seed, live, lambda a: TULIPY.macd(a, 12, 26, 9))
+
+
+def finta_macd_streaming(seed, live):
+    if FINTA is None or PD is None:
+        return None
+    return _finta_recompute_streaming(seed, live, lambda df: FINTA.TA.MACD(df))
+
+
+def talib_bollinger_streaming(seed, live):
+    if TALIB is None:
+        return None
+    return _talib_recompute_streaming(seed, live, lambda a: TALIB.BBANDS(a, timeperiod=20, nbdevup=2, nbdevdn=2))
+
+
+def pandas_ta_bollinger_streaming(seed, live):
+    if PANDAS_TA is None or PD is None:
+        return None
+    return _pandas_ta_recompute_streaming(seed, live, lambda s: PANDAS_TA.bbands(s, length=20, std=2.0))
+
+
+def tulipy_bollinger_streaming(seed, live):
+    if TULIPY is None:
+        return None
+    return _tulipy_recompute_streaming(seed, live, lambda a: TULIPY.bbands(a, 20, 2.0))
+
+
+def finta_bollinger_streaming(seed, live):
+    if FINTA is None or PD is None:
+        return None
+    return _finta_recompute_streaming(seed, live, lambda df: FINTA.TA.BBANDS(df, period=20, std_multiplier=2.0))
+
+
 # --------------------------------------------------------------------------- #
 # Runner
 # --------------------------------------------------------------------------- #
@@ -339,6 +632,7 @@ BATCH_INDICATORS = [
        ("Wickra", wickra_sma_batch),
        ("TA-Lib", talib_sma_batch),
        ("pandas-ta", pandas_ta_sma_batch),
+        ("tulipy", tulipy_sma_batch),
        ("finta", finta_sma_batch),
        ("talipp", talipp_sma_batch),
    ]),
@@ -346,6 +640,7 @@ BATCH_INDICATORS = [
        ("Wickra", wickra_ema_batch),
        ("TA-Lib", talib_ema_batch),
        ("pandas-ta", pandas_ta_ema_batch),
+        ("tulipy", tulipy_ema_batch),
        ("finta", finta_ema_batch),
        ("talipp", talipp_ema_batch),
    ]),
@@ -353,6 +648,7 @@ BATCH_INDICATORS = [
        ("Wickra", wickra_rsi_batch),
        ("TA-Lib", talib_rsi_batch),
        ("pandas-ta", pandas_ta_rsi_batch),
+        ("tulipy", tulipy_rsi_batch),
        ("finta", finta_rsi_batch),
        ("talipp", talipp_rsi_batch),
    ]),
@@ -360,6 +656,7 @@ BATCH_INDICATORS = [
        ("Wickra", wickra_macd_batch),
        ("TA-Lib", talib_macd_batch),
        ("pandas-ta", pandas_ta_macd_batch),
+        ("tulipy", tulipy_macd_batch),
        ("finta", finta_macd_batch),
        ("talipp", talipp_macd_batch),
    ]),
@@ -367,6 +664,7 @@ BATCH_INDICATORS = [
        ("Wickra", wickra_bollinger_batch),
        ("TA-Lib", talib_bollinger_batch),
        ("pandas-ta", pandas_ta_bollinger_batch),
+        ("tulipy", tulipy_bollinger_batch),
        ("finta", finta_bollinger_batch),
        ("talipp", talipp_bollinger_batch),
    ]),
@@ -376,29 +674,64 @@ OHLC_INDICATORS = [
    ("ATR(14)", [
        ("Wickra", wickra_atr_batch),
        ("TA-Lib", talib_atr_batch),
+        ("tulipy", tulipy_atr_batch),
        ("finta", finta_atr_batch),
        ("talipp", talipp_atr_batch),
    ]),
 ]

 STREAMING_INDICATORS = [
+    ("SMA(20)", [
+        ("Wickra", wickra_sma_streaming),
+        ("talipp", talipp_sma_streaming),
+        ("TA-Lib", talib_sma_streaming),
+        ("pandas-ta", pandas_ta_sma_streaming),
+        ("tulipy", tulipy_sma_streaming),
+        ("finta", finta_sma_streaming),
+    ]),
+    ("EMA(20)", [
+        ("Wickra", wickra_ema_streaming),
+        ("talipp", talipp_ema_streaming),
+        ("TA-Lib", talib_ema_streaming),
+        ("pandas-ta", pandas_ta_ema_streaming),
+        ("tulipy", tulipy_ema_streaming),
+        ("finta", finta_ema_streaming),
+    ]),
    ("RSI(14)", [
        ("Wickra", wickra_rsi_streaming),
+        ("talipp", talipp_rsi_streaming),
        ("TA-Lib", talib_rsi_streaming),
        ("pandas-ta", pandas_ta_rsi_streaming),
-        ("talipp", talipp_rsi_streaming),
+        ("tulipy", tulipy_rsi_streaming),
+        ("finta", finta_rsi_streaming),
+    ]),
+    ("MACD(12, 26, 9)", [
+        ("Wickra", wickra_macd_streaming),
+        ("talipp", talipp_macd_streaming),
+        ("TA-Lib", talib_macd_streaming),
+        ("pandas-ta", pandas_ta_macd_streaming),
+        ("tulipy", tulipy_macd_streaming),
+        ("finta", finta_macd_streaming),
+    ]),
+    ("Bollinger(20, 2.0)", [
+        ("Wickra", wickra_bollinger_streaming),
+        ("talipp", talipp_bollinger_streaming),
+        ("TA-Lib", talib_bollinger_streaming),
+        ("pandas-ta", pandas_ta_bollinger_streaming),
+        ("tulipy", tulipy_bollinger_streaming),
+        ("finta", finta_bollinger_streaming),
    ]),
 ]


-def run_batch(prices: np.ndarray, iterations: int) -> List[Sample]:
+def run_batch(prices: np.ndarray, iterations: int, rounds: int) -> List[Sample]:
    out: List[Sample] = []
    for indicator_name, libs in BATCH_INDICATORS:
        for lib_name, factory in libs:
            runner = factory(prices)
            if runner is None:
                continue
-            secs = time_call(runner, iterations)
+            secs = time_call(runner, iterations, rounds)
            out.append(Sample(lib_name, indicator_name, "batch", secs, iterations))
    return out

@@ -408,6 +741,7 @@ def run_ohlc(
    low: np.ndarray,
    close: np.ndarray,
    iterations: int,
+    rounds: int,
 ) -> List[Sample]:
    out: List[Sample] = []
    for indicator_name, libs in OHLC_INDICATORS:
@@ -415,12 +749,12 @@ def run_ohlc(
            runner = factory(high, low, close)
            if runner is None:
                continue
-            secs = time_call(runner, iterations)
+            secs = time_call(runner, iterations, rounds)
            out.append(Sample(lib_name, indicator_name, "batch", secs, iterations))
    return out


-def run_streaming(prices: np.ndarray, streaming_window: int, iterations: int) -> List[Sample]:
+def run_streaming(prices: np.ndarray, streaming_window: int, iterations: int, rounds: int) -> List[Sample]:
    out: List[Sample] = []
    seed = prices[:streaming_window]
    live = prices[streaming_window:]
@@ -431,7 +765,7 @@ def run_streaming(prices: np.ndarray, streaming_window: int, iterations: int) ->
            runner = factory(seed, live)
            if runner is None:
                continue
-            secs = time_call(runner, iterations)
+            secs = time_call(runner, iterations, rounds)
            sample = Sample(lib_name, indicator_name, "streaming", secs, iterations)
            sample.iterations = iterations * len(live)  # per-tick normalization
            out.append(sample)
@@ -479,6 +813,12 @@ def parse_args() -> argparse.Namespace:
    parser = argparse.ArgumentParser(description=__doc__.splitlines()[0] if __doc__ else None)
    parser.add_argument("--size", type=int, default=20_000, help="number of prices")
    parser.add_argument("--iterations", type=int, default=20, help="batch repetitions per timing")
+    parser.add_argument(
+        "--rounds",
+        type=int,
+        default=5,
+        help="batch timing rounds; the median round is reported to damp jitter",
+    )
    parser.add_argument(
        "--streaming-window",
        type=int,
@@ -491,6 +831,14 @@ def parse_args() -> argparse.Namespace:
        default=3,
        help="repetitions of the streaming workload (each iteration replays all live ticks)",
    )
+    parser.add_argument(
+        "--streaming-rounds",
+        type=int,
+        default=2,
+        help="streaming timing rounds; the median round is reported",
+    )
+    parser.add_argument("--skip-batch", action="store_true", help="skip the batch tables")
+    parser.add_argument("--skip-streaming", action="store_true", help="skip the streaming tables")
    return parser.parse_args()


@@ -501,6 +849,7 @@ def main() -> None:
    available = []
    if TALIB is not None: available.append("TA-Lib")
    if PANDAS_TA is not None: available.append("pandas-ta")
+    if TULIPY is not None: available.append("tulipy")
    if FINTA is not None: available.append("finta")
    if TALIPP is not None: available.append("talipp")
    print(f"Wickra benchmark suite — wickra=v{WICKRA.__version__}")
@@ -509,11 +858,14 @@ def main() -> None:
    print(f"Streaming window: {args.streaming_window} seed, {args.size - args.streaming_window} live")

    high, low, close, _ = gen_ohlc(args.size)
-    batch_rows = run_batch(prices, args.iterations)
-    ohlc_rows = run_ohlc(high, low, close, args.iterations)
-    streaming_rows = run_streaming(prices, args.streaming_window, args.streaming_iterations)
+    rows: List[Sample] = []
+    if not args.skip_batch:
+        rows += run_batch(prices, args.iterations, args.rounds)
+        rows += run_ohlc(high, low, close, args.iterations, args.rounds)
+    if not args.skip_streaming:
+        rows += run_streaming(prices, args.streaming_window, args.streaming_iterations, args.streaming_rounds)

-    print(render_table(batch_rows + ohlc_rows + streaming_rows))
+    print(render_table(rows))


 if __name__ == "__main__":
@@ -4,7 +4,7 @@ build-backend = "maturin"

 [project]
 name = "wickra"
-version = "0.5.3"
+version = "0.6.6"
 description = "Streaming-first technical indicators: incremental, fast, install-free."
 readme = "README.md"
 license = "MIT OR Apache-2.0"
@@ -39,6 +39,7 @@ bench = [
    "pytest-benchmark>=4",
    "TA-Lib; platform_system != 'Windows'",
    "pandas-ta>=0.3.14b",
+    "tulipy>=0.4; platform_system != 'Windows'",
    "talipp>=2",
    "finta>=1.3",
    "pandas>=2",
@@ -25,6 +25,69 @@ from __future__ import annotations

 from ._wickra import (
    __version__,
+    AUTOCORRPGRAM,
+    EVENBETTERSINE,
+    BANDPASS,
+    ADAPTIVECCI,
+    UNIVERSALOSC,
+    ADAPTIVERSI,
+    CTI,
+    TRENDFLEX,
+    REFLEX,
+    HIGHPASS,
+    SAMPLEENT,
+    SHANNONENT,
+    ROLLINGMINMAX,
+    JARQUEBERA,
+    TimeBasedStop,
+    ProjectionOscillator,
+    VolatilityCone,
+    VolatilityRatio,
+    BipowerVariation,
+    VolatilityOfVolatility,
+    Garch11,
+    EwmaVolatility,
+    PpoHistogram,
+    MacdHistogram,
+    TsfOscillator,
+    Qstick,
+    GatorOscillator,
+    KasePermissionStochastic,
+    WAVE_PM,
+    POLARIZED_FRACTAL_EFFICIENCY,
+    TREND_STRENGTH_INDEX,
+    TTM_TREND,
+    QQE,
+    IMI,
+    ElderRay,
+    DerivativeOscillator,
+    RMI,
+    StochasticCCI,
+    DynamicMomentumIndex,
+    RSX,
+    FisherRSI,
+    DisparityIndex,
+    HoltWinters,
+    GD,
+    AdaptiveLaguerre,
+    MedianMA,
+    EHMA,
+    GMA,
+    SWMA,
+    Expectancy,
+    WinRate,
+    RegimeLabel,
+    JumpIndicator,
+    TrendLabel,
+    HighLowRange,
+    WickRatio,
+    BodySizePct,
+    CloseVsOpen,
+    RollingQuantile,
+    RollingPercentileRank,
+    RollingIqr,
+    RealizedVolatility,
+    LogReturn,
    TSF,
    LINEARREG_INTERCEPT,
    ROCR100,
@@ -120,6 +183,11 @@ from ._wickra import (
    HistoricalVolatility,
    BollingerBandwidth,
    PercentB,
+    # Trailing Stops
+    ModifiedMaStop,
+    Nrtr,
+    AtrRatchet,
+    ElderSafeZone,
    SuperTrend,
    ChandelierExit,
    ChandeKrollStop,
@@ -131,6 +199,7 @@ from ._wickra import (
    PercentageTrailingStop,
    StepTrailingStop,
    RenkoTrailingStop,
+    KaseDevStop,
    TrueRange,
    ChaikinVolatility,
    RVIVolatility,
@@ -139,6 +208,13 @@ from ._wickra import (
    RogersSatchellVolatility,
    YangZhangVolatility,
    # Volume
+    VolumeWeightedMacd,
+    BetterVolume,
+    IntradayIntensity,
+    TradeVolumeIndex,
+    TwiggsMoneyFlow,
+    Wad,
+    VolumeRsi,
    OBV,
    VWAP,
    RollingVWAP,
@@ -159,6 +235,7 @@ from ._wickra import (
    MarketFacilitationIndex,
    EaseOfMovement,
    # Statistics
+    KendallTau,
    SpreadBollingerBands,
    KalmanHedgeRatio,
    GrangerCausality,
@@ -189,6 +266,7 @@ from ._wickra import (
    PearsonCorrelation,
    Beta,
    PairwiseBeta,
+    SpreadAr1Coefficient,
    PairSpreadZScore,
    LeadLagCrossCorrelation,
    Cointegration,
@@ -215,6 +293,10 @@ from ._wickra import (
    MAMA,
    FAMA,
    # Bands & Channels
+    ProjectionBands,
+    MedianChannel,
+    BomarBands,
+    QuartileBands,
    MaEnvelope,
    AccelerationBands,
    StarcBands,
@@ -227,6 +309,11 @@ from ._wickra import (
    FractalChaosBands,
    VwapStdDevBands,
    # Pivots & S/R
+    PivotReversal,
+    VolumeWeightedSr,
+    AndrewsPitchfork,
+    MurreyMathLines,
+    CentralPivotRange,
    ClassicPivots,
    FibonacciPivots,
    Camarilla,
@@ -351,6 +438,7 @@ from ._wickra import (
    FibExtension,
    FibRetracement,
    # Microstructure: order book
+    OrderFlowImbalance,
    OrderBookImbalanceTop1,
    OrderBookImbalanceTopN,
    OrderBookImbalanceFull,
@@ -358,6 +446,9 @@ from ._wickra import (
    QuotedSpread,
    DepthSlope,
    # Microstructure: trade flow
+    RollMeasure,
+    AmihudIlliquidity,
+    Vpin,
    SignedVolume,
    CumulativeVolumeDelta,
    TradeImbalance,
@@ -430,6 +521,69 @@ from ._wickra import (
 )

 __all__ = [
+    "AUTOCORRPGRAM",
+    "EVENBETTERSINE",
+    "BANDPASS",
+    "ADAPTIVECCI",
+    "UNIVERSALOSC",
+    "ADAPTIVERSI",
+    "CTI",
+    "TRENDFLEX",
+    "REFLEX",
+    "HIGHPASS",
+    "SAMPLEENT",
+    "SHANNONENT",
+    "ROLLINGMINMAX",
+    "JARQUEBERA",
+    "TimeBasedStop",
+    "ProjectionOscillator",
+    "VolatilityCone",
+    "VolatilityRatio",
+    "BipowerVariation",
+    "VolatilityOfVolatility",
+    "Garch11",
+    "EwmaVolatility",
+    "PpoHistogram",
+    "MacdHistogram",
+    "TsfOscillator",
+    "Qstick",
+    "GatorOscillator",
+    "KasePermissionStochastic",
+    "WAVE_PM",
+    "POLARIZED_FRACTAL_EFFICIENCY",
+    "TREND_STRENGTH_INDEX",
+    "TTM_TREND",
+    "QQE",
+    "IMI",
+    "ElderRay",
+    "DerivativeOscillator",
+    "RMI",
+    "StochasticCCI",
+    "DynamicMomentumIndex",
+    "RSX",
+    "FisherRSI",
+    "DisparityIndex",
+    "HoltWinters",
+    "GD",
+    "AdaptiveLaguerre",
+    "MedianMA",
+    "EHMA",
+    "GMA",
+    "SWMA",
+    "Expectancy",
+    "WinRate",
+    "RegimeLabel",
+    "JumpIndicator",
+    "TrendLabel",
+    "HighLowRange",
+    "WickRatio",
+    "BodySizePct",
+    "CloseVsOpen",
+    "RollingQuantile",
+    "RollingPercentileRank",
+    "RollingIqr",
+    "RealizedVolatility",
+    "LogReturn",
    "TSF",
    "LINEARREG_INTERCEPT",
    "ROCR100",
@@ -526,6 +680,11 @@ __all__ = [
    "HistoricalVolatility",
    "BollingerBandwidth",
    "PercentB",
+    # Trailing Stops
+    "ModifiedMaStop",
+    "Nrtr",
+    "AtrRatchet",
+    "ElderSafeZone",
    "SuperTrend",
    "ChandelierExit",
    "ChandeKrollStop",
@@ -537,6 +696,7 @@ __all__ = [
    "PercentageTrailingStop",
    "StepTrailingStop",
    "RenkoTrailingStop",
+    "KaseDevStop",
    "TrueRange",
    "ChaikinVolatility",
    "RVIVolatility",
@@ -545,6 +705,13 @@ __all__ = [
    "RogersSatchellVolatility",
    "YangZhangVolatility",
    # Volume
+    "VolumeWeightedMacd",
+    "BetterVolume",
+    "IntradayIntensity",
+    "TradeVolumeIndex",
+    "TwiggsMoneyFlow",
+    "Wad",
+    "VolumeRsi",
    "OBV",
    "VWAP",
    "RollingVWAP",
@@ -565,6 +732,7 @@ __all__ = [
    "MarketFacilitationIndex",
    "EaseOfMovement",
    # Statistics
+    "KendallTau",
    "SpreadBollingerBands",
    "KalmanHedgeRatio",
    "GrangerCausality",
@@ -595,6 +763,7 @@ __all__ = [
    "PearsonCorrelation",
    "Beta",
    "PairwiseBeta",
+    "SpreadAr1Coefficient",
    "PairSpreadZScore",
    "LeadLagCrossCorrelation",
    "Cointegration",
@@ -621,6 +790,10 @@ __all__ = [
    "MAMA",
    "FAMA",
    # Bands & Channels
+    "ProjectionBands",
+    "MedianChannel",
+    "BomarBands",
+    "QuartileBands",
    "MaEnvelope",
    "AccelerationBands",
    "StarcBands",
@@ -633,6 +806,11 @@ __all__ = [
    "FractalChaosBands",
    "VwapStdDevBands",
    # Pivots & S/R
+    "PivotReversal",
+    "VolumeWeightedSr",
+    "AndrewsPitchfork",
+    "MurreyMathLines",
+    "CentralPivotRange",
    "ClassicPivots",
    "FibonacciPivots",
    "Camarilla",
@@ -757,6 +935,7 @@ __all__ = [
    "FibExtension",
    "FibRetracement",
    # Microstructure: order book
+    "OrderFlowImbalance",
    "OrderBookImbalanceTop1",
    "OrderBookImbalanceTopN",
    "OrderBookImbalanceFull",
@@ -764,6 +943,9 @@ __all__ = [
    "QuotedSpread",
    "DepthSlope",
    # Microstructure: trade flow
+    "RollMeasure",
+    "AmihudIlliquidity",
+    "Vpin",
    "SignedVolume",
    "CumulativeVolumeDelta",
    "TradeImbalance",
@@ -45,6 +45,52 @@ def ohlcv() -> tuple[np.ndarray, np.ndarray, np.ndarray, np.ndarray]:
 # --- Scalar (f64 -> f64) indicators ---------------------------------------

 SCALAR = [
+    (ta.AUTOCORRPGRAM, (10, 48)),
+    (ta.EVENBETTERSINE, (40, 10)),
+    (ta.BANDPASS, (20, 0.3)),
+    (ta.UNIVERSALOSC, (20,)),
+    (ta.ADAPTIVERSI, (14,)),
+    (ta.CTI, (20,)),
+    (ta.TRENDFLEX, (20,)),
+    (ta.REFLEX, (20,)),
+    (ta.HIGHPASS, (48,)),
+    (ta.SAMPLEENT, (20, 2, 0.2)),
+    (ta.SHANNONENT, (20, 8)),
+    (ta.ROLLINGMINMAX, (20,)),
+    (ta.JARQUEBERA, (20,)),
+    (ta.BipowerVariation, (20,)),
+    (ta.VolatilityOfVolatility, (20, 20)),
+    (ta.Garch11, (0.000002, 0.1, 0.88)),
+    (ta.EwmaVolatility, (0.94,)),
+    (ta.PpoHistogram, (3, 6, 3)),
+    (ta.MacdHistogram, (3, 6, 3)),
+    (ta.TsfOscillator, (3,)),
+    (ta.WAVE_PM, (32, 3)),
+    (ta.POLARIZED_FRACTAL_EFFICIENCY, (10, 5)),
+    (ta.TREND_STRENGTH_INDEX, (20,)),
+    (ta.DerivativeOscillator, (14, 5, 3, 9)),
+    (ta.RMI, (14, 5)),
+    (ta.DynamicMomentumIndex, (14,)),
+    (ta.RSX, (14,)),
+    (ta.FisherRSI, (14,)),
+    (ta.DisparityIndex, (14,)),
+    (ta.HoltWinters, (0.2, 0.1)),
+    (ta.GD, (5, 0.7)),
+    (ta.AdaptiveLaguerre, (13,)),
+    (ta.MedianMA, (14,)),
+    (ta.EHMA, (9,)),
+    (ta.GMA, (14,)),
+    (ta.SWMA, (14,)),
+    (ta.Expectancy, (20,)),
+    (ta.WinRate, (20,)),
+    (ta.RegimeLabel, (5, 20)),
+    (ta.JumpIndicator, (20, 3.0)),
+    (ta.TrendLabel, (10,)),
+    (ta.RollingQuantile, (20, 0.5)),
+    (ta.RollingPercentileRank, (14,)),
+    (ta.RollingIqr, (14,)),
+    (ta.RealizedVolatility, (20,)),
+    (ta.LogReturn, (1,)),
    (ta.TSF, (14,)),
    (ta.LINEARREG_INTERCEPT, (14,)),
    (ta.ROCR100, (10,)),
@@ -140,6 +186,10 @@ SCALAR = [
 # Family 05 band/channel indicators with scalar input and multi-output.
 # `cols` is the expected number of band columns from `batch`.
 SCALAR_MULTI = {
+    "MedianChannel": (lambda: ta.MedianChannel(5, 2.0), 3),
+    "BomarBands": (lambda: ta.BomarBands(4, 0.85), 3),
+    "QuartileBands": (lambda: ta.QuartileBands(4), 3),
+    "Qqe": (lambda: ta.QQE(14, 5, 4.236), 2),
    "MaEnvelope": (lambda: ta.MaEnvelope(20, 0.025), 3),
    "LinRegChannel": (lambda: ta.LinRegChannel(20, 2.0), 3),
    "StandardErrorBands": (lambda: ta.StandardErrorBands(21, 2.0), 3),
@@ -167,6 +217,8 @@ def test_scalar_streaming_matches_batch(cls, args, sine_prices):
 # --- Two-series (asset, benchmark) indicators -----------------------------

 PAIR = [
+    (ta.KendallTau, (20,)),
+    (ta.SpreadAr1Coefficient, (40,)),
    (ta.GrangerCausality, (60, 1)),
    (ta.VarianceRatio, (60, 2)),
    (ta.BetaNeutralSpread, (20,)),
@@ -330,6 +382,46 @@ def test_relative_strength_streaming_matches_batch():
 # 6-tuple candle; the batch helper takes only the columns it needs.

 CANDLE_SCALAR = {
+    "PivotReversal": (
+        lambda: ta.PivotReversal(1, 1),
+        lambda ind, h, l, c, v: ind.batch(h, l, c),
+    ),
+    "ADAPTIVECCI": (lambda: ta.ADAPTIVECCI(20), lambda ind, h, l, c, v: ind.batch(h, l, c)),
+    "BetterVolume": (
+        lambda: ta.BetterVolume(14),
+        lambda ind, h, l, c, v: ind.batch(h, l, c, v),
+    ),
+    "IntradayIntensity": (
+        lambda: ta.IntradayIntensity(),
+        lambda ind, h, l, c, v: ind.batch(h, l, c, v),
+    ),
+    "TradeVolumeIndex": (
+        lambda: ta.TradeVolumeIndex(0.25),
+        lambda ind, h, l, c, v: ind.batch(c, v),
+    ),
+    "TwiggsMoneyFlow": (
+        lambda: ta.TwiggsMoneyFlow(21),
+        lambda ind, h, l, c, v: ind.batch(h, l, c, v),
+    ),
+    "Wad": (
+        lambda: ta.Wad(),
+        lambda ind, h, l, c, v: ind.batch(h, l, c),
+    ),
+    "VolumeRsi": (
+        lambda: ta.VolumeRsi(14),
+        lambda ind, h, l, c, v: ind.batch(c, v),
+    ),
+    "TimeBasedStop": (lambda: ta.TimeBasedStop(5), lambda ind, h, l, c, v: ind.batch(h, l, c)),
+    "ProjectionOscillator": (lambda: ta.ProjectionOscillator(14), lambda ind, h, l, c, v: ind.batch(h, l, c)),
+    "VolatilityRatio": (lambda: ta.VolatilityRatio(14), lambda ind, h, l, c, v: ind.batch(h, l, c)),
+    "TTM_TREND": (lambda: ta.TTM_TREND(6), lambda ind, h, l, c, v: ind.batch(h, l, c)),
+    "StochasticCCI": (lambda: ta.StochasticCCI(14), lambda ind, h, l, c, v: ind.batch(h, l, c)),
+    # Per-bar OHLC transforms (open matters). The streaming harness feeds
+    # open == close, so batch passes the close column in for open to match.
+    "HighLowRange": (lambda: ta.HighLowRange(), lambda ind, h, l, c, v: ind.batch(c, h, l, c)),
+    "WickRatio": (lambda: ta.WickRatio(), lambda ind, h, l, c, v: ind.batch(c, h, l, c)),
+    "BodySizePct": (lambda: ta.BodySizePct(), lambda ind, h, l, c, v: ind.batch(c, h, l, c)),
+    "CloseVsOpen": (lambda: ta.CloseVsOpen(), lambda ind, h, l, c, v: ind.batch(c, h, l, c)),
    "ThreeDrives": (
        lambda: ta.ThreeDrives(),
        lambda ind, h, l, c, v: ind.batch(c, h, l, c),
@@ -860,6 +952,81 @@ def test_candle_scalar_streaming_matches_batch(name, ohlcv):
 # --- Candle-input, multi-output indicators --------------------------------

 MULTI = {
+    "VolumeWeightedSr": (
+        lambda: ta.VolumeWeightedSr(3),
+        lambda ind, h, l, c, v: ind.batch(h, l, v),
+        2,
+    ),
+    "AndrewsPitchfork": (
+        lambda: ta.AndrewsPitchfork(2),
+        lambda ind, h, l, c, v: ind.batch(h, l),
+        3,
+    ),
+    "MurreyMathLines": (
+        lambda: ta.MurreyMathLines(4),
+        lambda ind, h, l, c, v: ind.batch(h, l),
+        9,
+    ),
+    "CentralPivotRange": (
+        lambda: ta.CentralPivotRange(),
+        lambda ind, h, l, c, v: ind.batch(h, l, c),
+        3,
+    ),
+    "VolumeWeightedMacd": (
+        lambda: ta.VolumeWeightedMacd(12, 26, 9),
+        lambda ind, h, l, c, v: ind.batch(c, v),
+        3,
+    ),
+    "ModifiedMaStop": (
+        lambda: ta.ModifiedMaStop(14),
+        lambda ind, h, l, c, v: ind.batch(h, l, c),
+        2,
+    ),
+    "Nrtr": (
+        lambda: ta.Nrtr(2.0),
+        lambda ind, h, l, c, v: ind.batch(h, l, c),
+        2,
+    ),
+    "AtrRatchet": (
+        lambda: ta.AtrRatchet(14, 4.0, 0.1),
+        lambda ind, h, l, c, v: ind.batch(h, l, c),
+        2,
+    ),
+    "ElderSafeZone": (
+        lambda: ta.ElderSafeZone(14, 2.0),
+        lambda ind, h, l, c, v: ind.batch(h, l, c),
+        2,
+    ),
+    "KaseDevStop": (
+        lambda: ta.KaseDevStop(3, 1.0),
+        lambda ind, h, l, c, v: ind.batch(h, l, c),
+        2,
+    ),
+    "ProjectionBands": (
+        lambda: ta.ProjectionBands(3),
+        lambda ind, h, l, c, v: ind.batch(h, l),
+        3,
+    ),
+    "VolatilityCone": (
+        lambda: ta.VolatilityCone(20, 60),
+        lambda ind, h, l, c, v: ind.batch(h, l, c),
+        5,
+    ),
+    "KasePermissionStochastic": (
+        lambda: ta.KasePermissionStochastic(9, 3),
+        lambda ind, h, l, c, v: ind.batch(h, l, c),
+        2,
+    ),
+    "GatorOscillator": (
+        lambda: ta.GatorOscillator(13, 8, 5),
+        lambda ind, h, l, c, v: ind.batch(h, l, c),
+        2,
+    ),
+    "ElderRay": (
+        lambda: ta.ElderRay(13),
+        lambda ind, h, l, c, v: ind.batch(h, l, c),
+        2,
+    ),
    "FibFan": (
        lambda: ta.FibFan(),
        lambda ind, h, l, c, v: ind.batch(h, l),
@@ -1481,7 +1648,7 @@ def test_kvo_constant_series_is_zero():
        assert v == pytest.approx(0.0, abs=1e-12)


-def test_williams_ad_reference():
+def test_wad_reference():
    # bar 0 seeds prev_close = 10.
    # bar 1: prev=10, today high=13, low=8, close=12 (up day).
    #   TR_l = min(10, 8) = 8 -> delta = 12 - 8 = 4. AD = 4.
@@ -2707,6 +2874,306 @@ def test_fib_time_zones_reference():
    assert t.update((151.0, 155.0, 151.0, 151.0, 1.0, 4)) == pytest.approx((0.0, 1.0))
    assert t.update((151.0, 155.0, 151.0, 151.0, 1.0, 5)) == pytest.approx((1.0, 3.0))

+
+def test_spread_ar1_coefficient_reference():
+    t = ta.SpreadAr1Coefficient(20)
+    assert t.update(1.0, 1.0) is None
+    # Spread a - b grows by exactly 1 each bar (unit root) => rho == 1.
+    a = np.array([2.0 * i for i in range(40)])
+    b = np.array([float(i) for i in range(40)])
+    out = ta.SpreadAr1Coefficient(20).batch(a, b)
+    assert math.isclose(out[-1], 1.0, abs_tol=1e-9)
+
+
+def test_elder_ray_reference():
+    er = ta.ElderRay(3)
+    high = np.array([11.0, 13.0, 16.0])
+    low = np.array([9.0, 11.0, 13.0])
+    close = np.array([10.0, 12.0, 14.0])
+    out = er.batch(high, low, close)
+    # EMA(3) seeds at the third bar with mean close 12; bar high 16 -> bull 4,
+    # low 13 -> bear 1.
+    assert out[2][0] == pytest.approx(4.0)
+    assert out[2][1] == pytest.approx(1.0)
+
+
+def test_imi_reference():
+    imi = ta.IMI(3)
+    open_ = np.array([10.0, 11.0, 10.0])
+    high = np.array([12.0, 12.0, 13.0])
+    low = np.array([9.0, 9.0, 9.0])
+    close = np.array([11.0, 10.0, 12.0])
+    out = imi.batch(open_, high, low, close)
+    # bodies +1, -1, +2 -> gain 3, loss 1 -> 100 * 3 / 4 = 75.
+    assert math.isnan(out[0])
+    assert math.isnan(out[1])
+    assert out[2] == pytest.approx(75.0)
+
+
+def test_qstick_reference():
+    q = ta.Qstick(3)
+    open_ = np.array([10.0, 10.0, 10.0])
+    close = np.array([11.0, 11.0, 11.0])
+    out = q.batch(open_, close)
+    # Each body is close - open = 1; SMA(3) of [1, 1, 1] = 1.
+    assert math.isnan(out[0])
+    assert math.isnan(out[1])
+    assert out[2] == pytest.approx(1.0)
+
+
+def test_ttm_trend_reference():
+    t = ta.TTM_TREND(3)
+    high = np.array([13.0, 13.0, 13.0])
+    low = np.array([9.0, 9.0, 9.0])
+    close = np.array([12.0, 12.0, 12.0])
+    out = t.batch(high, low, close)
+    # Median (13 + 9) / 2 = 11; close 12 is above the SMA(3) reference -> +1.
+    assert math.isnan(out[0])
+    assert out[2] == pytest.approx(1.0)
+
+
+def test_trend_strength_index_reference():
+    tsi = ta.TREND_STRENGTH_INDEX(10)
+    closes = np.arange(10, dtype=float)
+    out = tsi.batch(closes)
+    # A clean ramp is a perfect uptrend -> signed r^2 = +1.
+    assert math.isclose(out[-1], 1.0, abs_tol=1e-9)
+
+
+def test_polarized_fractal_efficiency_reference():
+    pfe = ta.POLARIZED_FRACTAL_EFFICIENCY(5, 3)
+    closes = np.arange(20, dtype=float)
+    out = pfe.batch(closes)
+    # On a straight ramp the path equals the diagonal -> efficiency 1 -> +100.
+    assert math.isclose(out[-1], 100.0, abs_tol=1e-9)
+
+
+def test_wave_pm_reference():
+    wpm = ta.WAVE_PM(10, 3)
+    closes = np.arange(60, dtype=float) * 5.0
+    out = wpm.batch(closes)
+    # Constant-slope ramp: momentum equals its energy -> 100 * (1 - e^-0.5).
+    baseline = 100.0 * (1.0 - math.exp(-0.5))
+    assert math.isclose(out[-1], baseline, abs_tol=1e-9)
+
+
+def test_gator_oscillator_reference():
+    g = ta.GatorOscillator(13, 8, 5)
+    n = 40
+    high = np.full(n, 11.0)
+    low = np.full(n, 9.0)
+    close = np.full(n, 10.0)
+    out = g.batch(high, low, close)
+    # Constant median collapses all three Alligator lines -> both bars zero.
+    assert out[-1][0] == pytest.approx(0.0)
+    assert out[-1][1] == pytest.approx(0.0)
+
+
+def test_kase_permission_stochastic_reference():
+    k = ta.KasePermissionStochastic(4, 2)
+    n = 20
+    flat = np.full(n, 10.0)
+    out = k.batch(flat, flat, flat)
+    # HH == LL -> raw %K defaults to the neutral 50 -> both lines at 50.
+    assert out[-1][0] == pytest.approx(50.0)
+    assert out[-1][1] == pytest.approx(50.0)
+
+
+def test_tsf_oscillator_reference():
+    t = ta.TsfOscillator(3)
+    assert t.update(1.0) is None
+    assert t.update(2.0) is None
+    assert t.update(9.0) == pytest.approx(-33.33333333333333)
+
+
+def test_macd_histogram_reference():
+    # On a constant-slope ramp the MACD line is flat once seeded, so the
+    # signal EMA catches up and the histogram collapses to 0.
+    t = ta.MacdHistogram(3, 6, 3)
+    for i in range(7):
+        assert t.update(100.0 + i * 2.0) is None
+    assert t.update(100.0 + 7 * 2.0) == pytest.approx(0.0, abs=1e-9)
+
+
+def test_ppo_histogram_reference():
+    # PPO divides the EMA gap by the slow EMA, so on the same ramp the ratio
+    # keeps drifting and the histogram stays non-zero.
+    t = ta.PpoHistogram(3, 6, 3)
+    for i in range(7):
+        assert t.update(100.0 + i * 2.0) is None
+    assert t.update(100.0 + 7 * 2.0) == pytest.approx(-0.052098, abs=1e-6)
+
+
+def test_ewma_volatility_reference():
+    t = ta.EwmaVolatility(0.94)
+    assert t.update(100.0) is None
+    assert t.update(110.0) == pytest.approx(0.09531017980432493)
+    assert t.update(99.0) == pytest.approx(0.0959428936787596)
+
+
+def test_garch11_reference():
+    t = ta.Garch11(0.000002, 0.1, 0.88)
+    assert t.update(100.0) is None
+    assert t.update(110.0) == pytest.approx(0.009999999999999995)
+    assert t.update(99.0) == pytest.approx(0.031597516317477786)
+
+
+def test_volatility_cone_reference():
+    t = ta.VolatilityCone(20, 60)
+
+
+def test_quartile_bands_reference():
+    t = ta.QuartileBands(4)
+    assert t.update(40.0) is None
+    assert t.update(30.0) is None
+    assert t.update(20.0) is None
+    assert t.update(10.0) == pytest.approx((32.5, 25.0, 17.5))
+
+
+def test_bomar_bands_reference():
+    t = ta.BomarBands(4, 0.85)
+    assert t.update(100.0) is None
+    assert t.update(102.0) is None
+    assert t.update(98.0) is None
+    assert t.update(104.0) == pytest.approx((104.0, 101.0, 98.0))
+
+
+def test_median_channel_reference():
+    t = ta.MedianChannel(5, 2.0)
+    assert t.update(1.0) is None
+    assert t.update(2.0) is None
+    assert t.update(3.0) is None
+    assert t.update(4.0) is None
+    assert t.update(5.0) == pytest.approx((5.0, 3.0, 1.0))
+
+
+def test_projection_bands_reference():
+    t = ta.ProjectionBands(3)
+    assert t.update((8.0, 10.0, 8.0, 9.0, 1.0, 0)) is None
+    assert t.update((9.0, 12.0, 9.0, 11.0, 1.0, 1)) is None
+    assert t.update((10.0, 11.0, 10.0, 11.0, 1.0, 2)) == pytest.approx((12.5, 11.25, 10.0))
+
+
+def test_projection_oscillator_reference():
+    # Same window as ProjectionBands: upper 12.5, lower 10; close 11 -> 40.
+    t = ta.ProjectionOscillator(3)
+    assert t.update((8.0, 10.0, 8.0, 9.0, 1.0, 0)) is None
+    assert t.update((9.0, 12.0, 9.0, 11.0, 1.0, 1)) is None
+    assert t.update((10.0, 11.0, 10.0, 11.0, 1.0, 2)) == pytest.approx(40.0)
+
+
+def test_kase_devstop_reference():
+    t = ta.KaseDevStop(3, 1.0)
+    assert t.update((100.0, 101.0, 99.0, 100.0, 1.0, 0)) is None
+    assert t.update((101.0, 102.0, 100.0, 101.0, 1.0, 1)) is None
+    assert t.update((102.0, 103.0, 101.0, 102.0, 1.0, 2)) is None
+    assert t.update((102.5, 104.0, 102.0, 103.0, 1.0, 3)) == pytest.approx((101.0, 1.0))
+
+
+def _stop_candles(n):
+    # Gently rising, valid OHLC: high >= open/close, low <= open/close.
+    return [(100.0 + i, 101.5 + i, 98.5 + i, 100.5 + i, 1.0, i) for i in range(n)]
+
+
+def test_elder_safezone_reference():
+    t = ta.ElderSafeZone(14, 2.0)
+    candles = _stop_candles(15)
+    for c in candles[:14]:
+        assert t.update(c) is None
+    assert t.update(candles[14]) == pytest.approx((112.5, 1.0))
+
+
+def test_atr_ratchet_reference():
+    t = ta.AtrRatchet(14, 4.0, 0.1)
+    candles = _stop_candles(14)
+    for c in candles[:13]:
+        assert t.update(c) is None
+    assert t.update(candles[13]) == pytest.approx((101.5, 1.0))
+
+
+def test_nrtr_reference():
+    t = ta.Nrtr(2.0)
+    assert t.update((100.0, 100.0, 100.0, 100.0, 1.0, 0)) == pytest.approx((98.0, 1.0))
+
+
+def test_time_based_stop_reference():
+    t = ta.TimeBasedStop(5)
+    assert t.update((100.0, 101.0, 99.0, 100.0, 1.0, 0)) == pytest.approx(0.2)
+
+
+def test_modified_ma_stop_reference():
+    t = ta.ModifiedMaStop(14)
+    candles = _stop_candles(14)
+    for c in candles[:13]:
+        assert t.update(c) is None
+    assert t.update(candles[13]) == pytest.approx((107.0, 1.0))
+
+
+def test_volume_rsi_reference():
+    t = ta.VolumeRsi(14)
+
+
+def test_twiggs_money_flow_reference():
+    t = ta.TwiggsMoneyFlow(21)
+
+
+def test_trade_volume_index_reference():
+    t = ta.TradeVolumeIndex(0.25)
+
+
+def test_intraday_intensity_reference():
+    t = ta.IntradayIntensity()
+
+
+def test_better_volume_reference():
+    t = ta.BetterVolume(14)
+
+
+def test_volume_weighted_macd_reference():
+    t = ta.VolumeWeightedMacd(12, 26, 9)
+
+
+def test_kendall_tau_reference():
+    t = ta.KendallTau(20)
+
+
+def test_central_pivot_range_reference():
+    t = ta.CentralPivotRange()
+    assert t.update((105.0, 110.0, 90.0, 105.0, 1.0, 0)) == pytest.approx((101.66666666666667, 103.33333333333334, 100.0))
+
+
+def test_murrey_math_lines_reference():
+    t = ta.MurreyMathLines(4)
+    assert t.update((140.0, 180.0, 100.0, 140.0, 1.0, 0)) is None
+    assert t.update((140.0, 180.0, 100.0, 140.0, 1.0, 1)) is None
+    assert t.update((140.0, 180.0, 100.0, 140.0, 1.0, 2)) is None
+    assert t.update((140.0, 180.0, 100.0, 140.0, 1.0, 3)) == pytest.approx((180.0, 170.0, 160.0, 150.0, 140.0, 130.0, 120.0, 110.0, 100.0))
+
+
+def test_andrews_pitchfork_reference():
+    t = ta.AndrewsPitchfork(2)
+    # Warmup: no pitchfork until three alternating swing pivots are confirmed.
+    assert t.update((100.0, 101.0, 99.0, 100.0, 1.0, 0)) is None
+
+
+def test_volume_weighted_sr_reference():
+    t = ta.VolumeWeightedSr(3)
+    assert t.update((100.0, 102.0, 98.0, 100.0, 1.0, 0)) is None
+    assert t.update((100.0, 104.0, 96.0, 100.0, 1.0, 1)) is None
+    assert t.update((100.0, 106.0, 94.0, 100.0, 1.0, 2)) == pytest.approx((96.0, 104.0))
+
+
+def test_pivot_reversal_reference():
+    t = ta.PivotReversal(1, 1)
+    assert t.update((9.5, 10.0, 9.0, 9.5, 1.0, 0)) is None
+    assert t.update((11.5, 12.0, 11.0, 11.5, 1.0, 1)) is None
+    # Pivot high = 12 confirmed; close 9.5 has not crossed it.
+    assert t.update((9.5, 10.0, 9.0, 9.5, 1.0, 2)) == pytest.approx(0.0)
+    assert t.update((9.0, 11.0, 9.0, 9.0, 1.0, 3)) == pytest.approx(0.0)
+    # Close 13 > pivot high 12 with prev close 9 below it -> bullish reversal.
+    assert t.update((13.0, 14.0, 12.5, 13.0, 1.0, 4)) == pytest.approx(1.0)
+
+
 # --- Lifecycle ------------------------------------------------------------


@@ -3024,6 +3491,7 @@ def test_orderbook_indicators_streaming_equals_batch():
        ta.Microprice,
        ta.QuotedSpread,
        ta.DepthSlope,
+        lambda: ta.OrderFlowImbalance(10),
    ):
        batch = make().batch(snaps)
        streamer = make()
@@ -3043,6 +3511,9 @@ def test_tradeflow_indicators_streaming_equals_batch():
        ta.SignedVolume,
        ta.CumulativeVolumeDelta,
        lambda: ta.TradeImbalance(5),
+        lambda: ta.Vpin(8.0, 5),
+        lambda: ta.AmihudIlliquidity(14),
+        lambda: ta.RollMeasure(14),
    ):
        batch = make().batch(price, size, is_buy)
        streamer = make()
@@ -0,0 +1,22 @@
+[package]
+name = "wickra-bench"
+version.workspace = true
+edition.workspace = true
+license.workspace = true
+publish = false
+description = "Internal cross-library benchmark harness (not published)."
+
+[lints]
+workspace = true
+
+[dev-dependencies]
+wickra = { path = "../wickra" }
+wickra-data = { path = "../wickra-data" }
+criterion = { workspace = true }
+kand = "0.2.2"
+ta = "0.5.0"
+yata = "0.7.0"
+
+[[bench]]
+name = "cross_lib"
+harness = false
@@ -0,0 +1,699 @@
+//! Cross-library Criterion benchmark: Wickra vs `kand` vs `ta` (ta-rs) vs `yata`.
+//!
+//! All four are pure-Rust technical-analysis crates, so this is a like-for-like
+//! Rust-vs-Rust comparison with no language-binding overhead. It feeds the exact
+//! same BTCUSDT 1-minute candle series used by `crates/wickra/benches/indicators.rs`.
+//!
+//! Two arenas, kept honest:
+//!
+//! * **Streaming** (`*/stream`): one value fed at a time. Wickra (`Indicator::update`),
+//!   ta-rs (`Next::next`) and yata (`Method::next`) carry their own state; `kand`
+//!   exposes stateless `*_inc` helpers, so the per-tick state is threaded manually
+//!   here, seeded from `kand`'s own batch output (the seed is computed outside the
+//!   timed closure). yata only appears for SMA/EMA — its RSI/MACD/Bollinger/ATR are
+//!   exposed through a heavier signal-oriented indicator API, not a raw-value method,
+//!   so they are intentionally left out rather than compared unfairly.
+//! * **Batch** (`*/batch`): the whole series at once. Only Wickra (`BatchExt::batch`)
+//!   and `kand` (TA-Lib-style fill-the-output-slice functions) have a real batch API;
+//!   ta-rs and yata are streaming-only and are deliberately absent from this arena.
+//!
+//! Run: `cargo bench -p wickra-bench`
+
+// Each indicator's benchmark group spells out every library arm explicitly, which
+// runs a few groups over the 100-line lint threshold; that verbosity is the point.
+#![allow(clippy::too_many_lines)]
+
+use criterion::{criterion_group, criterion_main, BenchmarkId, Criterion, Throughput};
+use std::hint::black_box;
+use wickra::{Atr, BollingerBands, Candle, Ema, Indicator, MacdIndicator, Rsi, Sma};
+use wickra_data::csv::CandleReader;
+use yata::prelude::Method;
+
+const SIZES: &[usize] = &[1_000, 10_000, 50_000];
+
+const SMA_PERIOD: usize = 20;
+const EMA_PERIOD: usize = 20;
+const RSI_PERIOD: usize = 14;
+const ATR_PERIOD: usize = 14;
+const BB_PERIOD: usize = 20;
+const BB_DEV: f64 = 2.0;
+const MACD_FAST: usize = 12;
+const MACD_SLOW: usize = 26;
+const MACD_SIGNAL: usize = 9;
+
+fn load_candles() -> Vec<Candle> {
+    let path = concat!(
+        env!("CARGO_MANIFEST_DIR"),
+        "/../../examples/data/btcusdt-1m.csv"
+    );
+    CandleReader::open(path)
+        .expect("dataset present")
+        .read_all()
+        .expect("valid OHLCV rows")
+}
+
+/// Mean of the first `period` samples — the warmup seed for `kand`'s SMA/EMA `*_inc`.
+fn window_mean(series: &[f64], period: usize) -> f64 {
+    series[..period].iter().sum::<f64>() / period as f64
+}
+
+fn sma_group(crit: &mut Criterion, closes: &[f64]) {
+    let mut group = crit.benchmark_group("sma_20");
+    for &len in SIZES {
+        let len = len.min(closes.len());
+        let series: &[f64] = &closes[..len];
+        group.throughput(Throughput::Elements(len as u64));
+
+        group.bench_with_input(
+            BenchmarkId::new("wickra/stream", len),
+            &series,
+            |bencher, &series| {
+                bencher.iter(|| {
+                    let mut ind = Sma::new(SMA_PERIOD).unwrap();
+                    for &price in series {
+                        black_box(ind.update(price));
+                    }
+                });
+            },
+        );
+        group.bench_with_input(
+            BenchmarkId::new("wickra/batch", len),
+            &series,
+            |bencher, &series| {
+                bencher.iter(|| {
+                    let mut ind = Sma::new(SMA_PERIOD).unwrap();
+                    black_box(ind.batch_nan(series));
+                });
+            },
+        );
+        group.bench_with_input(
+            BenchmarkId::new("kand/stream", len),
+            &series,
+            |bencher, &series| {
+                let seed = window_mean(series, SMA_PERIOD);
+                bencher.iter(|| {
+                    let mut prev = seed;
+                    for idx in SMA_PERIOD..series.len() {
+                        prev = kand::ohlcv::sma::sma_inc(
+                            prev,
+                            series[idx],
+                            series[idx - SMA_PERIOD],
+                            SMA_PERIOD,
+                        )
+                        .unwrap();
+                        black_box(prev);
+                    }
+                });
+            },
+        );
+        group.bench_with_input(
+            BenchmarkId::new("kand/batch", len),
+            &series,
+            |bencher, &series| {
+                bencher.iter(|| {
+                    let mut out = vec![0.0; series.len()];
+                    kand::ohlcv::sma::sma(series, SMA_PERIOD, &mut out).unwrap();
+                    black_box(&out);
+                });
+            },
+        );
+        group.bench_with_input(
+            BenchmarkId::new("ta-rs/stream", len),
+            &series,
+            |bencher, &series| {
+                bencher.iter(|| {
+                    let mut ind = ta::indicators::SimpleMovingAverage::new(SMA_PERIOD).unwrap();
+                    for &price in series {
+                        black_box(ta::Next::next(&mut ind, price));
+                    }
+                });
+            },
+        );
+        group.bench_with_input(
+            BenchmarkId::new("yata/stream", len),
+            &series,
+            |bencher, &series| {
+                bencher.iter(|| {
+                    let mut ind = yata::methods::SMA::new(SMA_PERIOD as u8, &series[0]).unwrap();
+                    for price in series {
+                        black_box(ind.next(price));
+                    }
+                });
+            },
+        );
+    }
+    group.finish();
+}
+
+fn ema_group(crit: &mut Criterion, closes: &[f64]) {
+    let mut group = crit.benchmark_group("ema_20");
+    for &len in SIZES {
+        let len = len.min(closes.len());
+        let series: &[f64] = &closes[..len];
+        group.throughput(Throughput::Elements(len as u64));
+
+        group.bench_with_input(
+            BenchmarkId::new("wickra/stream", len),
+            &series,
+            |bencher, &series| {
+                bencher.iter(|| {
+                    let mut ind = Ema::new(EMA_PERIOD).unwrap();
+                    for &price in series {
+                        black_box(ind.update(price));
+                    }
+                });
+            },
+        );
+        group.bench_with_input(
+            BenchmarkId::new("wickra/batch", len),
+            &series,
+            |bencher, &series| {
+                bencher.iter(|| {
+                    let mut ind = Ema::new(EMA_PERIOD).unwrap();
+                    black_box(ind.batch_nan(series));
+                });
+            },
+        );
+        group.bench_with_input(
+            BenchmarkId::new("kand/stream", len),
+            &series,
+            |bencher, &series| {
+                let seed = window_mean(series, EMA_PERIOD);
+                bencher.iter(|| {
+                    let mut prev = seed;
+                    for &price in &series[EMA_PERIOD..] {
+                        prev = kand::ohlcv::ema::ema_inc(price, prev, EMA_PERIOD, None).unwrap();
+                        black_box(prev);
+                    }
+                });
+            },
+        );
+        group.bench_with_input(
+            BenchmarkId::new("kand/batch", len),
+            &series,
+            |bencher, &series| {
+                bencher.iter(|| {
+                    let mut out = vec![0.0; series.len()];
+                    kand::ohlcv::ema::ema(series, EMA_PERIOD, None, &mut out).unwrap();
+                    black_box(&out);
+                });
+            },
+        );
+        group.bench_with_input(
+            BenchmarkId::new("ta-rs/stream", len),
+            &series,
+            |bencher, &series| {
+                bencher.iter(|| {
+                    let mut ind =
+                        ta::indicators::ExponentialMovingAverage::new(EMA_PERIOD).unwrap();
+                    for &price in series {
+                        black_box(ta::Next::next(&mut ind, price));
+                    }
+                });
+            },
+        );
+        group.bench_with_input(
+            BenchmarkId::new("yata/stream", len),
+            &series,
+            |bencher, &series| {
+                bencher.iter(|| {
+                    let mut ind = yata::methods::EMA::new(EMA_PERIOD as u8, &series[0]).unwrap();
+                    for price in series {
+                        black_box(ind.next(price));
+                    }
+                });
+            },
+        );
+    }
+    group.finish();
+}
+
+fn rsi_group(crit: &mut Criterion, closes: &[f64]) {
+    let mut group = crit.benchmark_group("rsi_14");
+    for &len in SIZES {
+        let len = len.min(closes.len());
+        let series: &[f64] = &closes[..len];
+        group.throughput(Throughput::Elements(len as u64));
+
+        group.bench_with_input(
+            BenchmarkId::new("wickra/stream", len),
+            &series,
+            |bencher, &series| {
+                bencher.iter(|| {
+                    let mut ind = Rsi::new(RSI_PERIOD).unwrap();
+                    for &price in series {
+                        black_box(ind.update(price));
+                    }
+                });
+            },
+        );
+        group.bench_with_input(
+            BenchmarkId::new("wickra/batch", len),
+            &series,
+            |bencher, &series| {
+                bencher.iter(|| {
+                    let mut ind = Rsi::new(RSI_PERIOD).unwrap();
+                    black_box(ind.batch_nan(series));
+                });
+            },
+        );
+        group.bench_with_input(
+            BenchmarkId::new("kand/stream", len),
+            &series,
+            |bencher, &series| {
+                // Wilder seed: simple average of the first `period` gains and losses.
+                let mut gain = 0.0;
+                let mut loss = 0.0;
+                for idx in 1..=RSI_PERIOD {
+                    let delta = series[idx] - series[idx - 1];
+                    if delta > 0.0 {
+                        gain += delta;
+                    } else {
+                        loss -= delta;
+                    }
+                }
+                let seed_gain = gain / RSI_PERIOD as f64;
+                let seed_loss = loss / RSI_PERIOD as f64;
+                bencher.iter(|| {
+                    let mut avg_gain = seed_gain;
+                    let mut avg_loss = seed_loss;
+                    let mut prev_price = series[RSI_PERIOD];
+                    for &price in &series[RSI_PERIOD + 1..] {
+                        let (rsi, next_gain, next_loss) = kand::ohlcv::rsi::rsi_inc(
+                            price, prev_price, avg_gain, avg_loss, RSI_PERIOD,
+                        )
+                        .unwrap();
+                        avg_gain = next_gain;
+                        avg_loss = next_loss;
+                        prev_price = price;
+                        black_box(rsi);
+                    }
+                });
+            },
+        );
+        group.bench_with_input(
+            BenchmarkId::new("kand/batch", len),
+            &series,
+            |bencher, &series| {
+                bencher.iter(|| {
+                    let mut rsi = vec![0.0; series.len()];
+                    let mut avg_gain = vec![0.0; series.len()];
+                    let mut avg_loss = vec![0.0; series.len()];
+                    kand::ohlcv::rsi::rsi(
+                        series,
+                        RSI_PERIOD,
+                        &mut rsi,
+                        &mut avg_gain,
+                        &mut avg_loss,
+                    )
+                    .unwrap();
+                    black_box(&rsi);
+                });
+            },
+        );
+        group.bench_with_input(
+            BenchmarkId::new("ta-rs/stream", len),
+            &series,
+            |bencher, &series| {
+                bencher.iter(|| {
+                    let mut ind = ta::indicators::RelativeStrengthIndex::new(RSI_PERIOD).unwrap();
+                    for &price in series {
+                        black_box(ta::Next::next(&mut ind, price));
+                    }
+                });
+            },
+        );
+    }
+    group.finish();
+}
+
+fn macd_group(crit: &mut Criterion, closes: &[f64]) {
+    let mut group = crit.benchmark_group("macd_12_26_9");
+    for &len in SIZES {
+        let len = len.min(closes.len());
+        let series: &[f64] = &closes[..len];
+        group.throughput(Throughput::Elements(len as u64));
+
+        group.bench_with_input(
+            BenchmarkId::new("wickra/stream", len),
+            &series,
+            |bencher, &series| {
+                bencher.iter(|| {
+                    let mut ind = MacdIndicator::classic();
+                    for &price in series {
+                        black_box(ind.update(price));
+                    }
+                });
+            },
+        );
+        group.bench_with_input(
+            BenchmarkId::new("wickra/batch", len),
+            &series,
+            |bencher, &series| {
+                bencher.iter(|| {
+                    let mut ind = MacdIndicator::classic();
+                    black_box(ind.batch_macd(series));
+                });
+            },
+        );
+        group.bench_with_input(
+            BenchmarkId::new("kand/stream", len),
+            &series,
+            |bencher, &series| {
+                // Seed the fast/slow/signal EMAs from kand's own warmed-up batch state.
+                let lookback =
+                    kand::ohlcv::macd::lookback(MACD_FAST, MACD_SLOW, MACD_SIGNAL).unwrap();
+                let mut macd_line = vec![0.0; series.len()];
+                let mut signal_line = vec![0.0; series.len()];
+                let mut histogram = vec![0.0; series.len()];
+                let mut fast_ema = vec![0.0; series.len()];
+                let mut slow_ema = vec![0.0; series.len()];
+                kand::ohlcv::macd::macd(
+                    series,
+                    MACD_FAST,
+                    MACD_SLOW,
+                    MACD_SIGNAL,
+                    &mut macd_line,
+                    &mut signal_line,
+                    &mut histogram,
+                    &mut fast_ema,
+                    &mut slow_ema,
+                )
+                .unwrap();
+                let seed_fast = fast_ema[lookback];
+                let seed_slow = slow_ema[lookback];
+                let seed_signal = signal_line[lookback];
+                bencher.iter(|| {
+                    // macd_inc returns (macd, signal, hist) but not the new EMAs, so the
+                    // fast/slow/signal state is threaded with kand's own ema_inc primitive.
+                    let mut prev_fast = seed_fast;
+                    let mut prev_slow = seed_slow;
+                    let mut prev_signal = seed_signal;
+                    for &price in &series[lookback + 1..] {
+                        let fast =
+                            kand::ohlcv::ema::ema_inc(price, prev_fast, MACD_FAST, None).unwrap();
+                        let slow =
+                            kand::ohlcv::ema::ema_inc(price, prev_slow, MACD_SLOW, None).unwrap();
+                        let macd = fast - slow;
+                        let signal =
+                            kand::ohlcv::ema::ema_inc(macd, prev_signal, MACD_SIGNAL, None)
+                                .unwrap();
+                        prev_fast = fast;
+                        prev_slow = slow;
+                        prev_signal = signal;
+                        black_box((macd, signal, macd - signal));
+                    }
+                });
+            },
+        );
+        group.bench_with_input(
+            BenchmarkId::new("kand/batch", len),
+            &series,
+            |bencher, &series| {
+                bencher.iter(|| {
+                    let mut macd_line = vec![0.0; series.len()];
+                    let mut signal_line = vec![0.0; series.len()];
+                    let mut histogram = vec![0.0; series.len()];
+                    let mut fast_ema = vec![0.0; series.len()];
+                    let mut slow_ema = vec![0.0; series.len()];
+                    kand::ohlcv::macd::macd(
+                        series,
+                        MACD_FAST,
+                        MACD_SLOW,
+                        MACD_SIGNAL,
+                        &mut macd_line,
+                        &mut signal_line,
+                        &mut histogram,
+                        &mut fast_ema,
+                        &mut slow_ema,
+                    )
+                    .unwrap();
+                    black_box(&macd_line);
+                });
+            },
+        );
+        group.bench_with_input(
+            BenchmarkId::new("ta-rs/stream", len),
+            &series,
+            |bencher, &series| {
+                bencher.iter(|| {
+                    let mut ind = ta::indicators::MovingAverageConvergenceDivergence::new(
+                        MACD_FAST,
+                        MACD_SLOW,
+                        MACD_SIGNAL,
+                    )
+                    .unwrap();
+                    for &price in series {
+                        black_box(ta::Next::next(&mut ind, price));
+                    }
+                });
+            },
+        );
+    }
+    group.finish();
+}
+
+fn bbands_group(crit: &mut Criterion, closes: &[f64]) {
+    let mut group = crit.benchmark_group("bollinger_20_2");
+    for &len in SIZES {
+        let len = len.min(closes.len());
+        let series: &[f64] = &closes[..len];
+        group.throughput(Throughput::Elements(len as u64));
+
+        group.bench_with_input(
+            BenchmarkId::new("wickra/stream", len),
+            &series,
+            |bencher, &series| {
+                bencher.iter(|| {
+                    let mut ind = BollingerBands::new(BB_PERIOD, BB_DEV).unwrap();
+                    for &price in series {
+                        black_box(ind.update(price));
+                    }
+                });
+            },
+        );
+        group.bench_with_input(
+            BenchmarkId::new("wickra/batch", len),
+            &series,
+            |bencher, &series| {
+                bencher.iter(|| {
+                    let mut ind = BollingerBands::new(BB_PERIOD, BB_DEV).unwrap();
+                    black_box(ind.batch_bands(series));
+                });
+            },
+        );
+        group.bench_with_input(
+            BenchmarkId::new("kand/stream", len),
+            &series,
+            |bencher, &series| {
+                // Seed running sma/sum/sum_sq from kand's batch state at the warmup edge.
+                let mut upper = vec![0.0; series.len()];
+                let mut middle = vec![0.0; series.len()];
+                let mut lower = vec![0.0; series.len()];
+                let mut sma = vec![0.0; series.len()];
+                let mut variance = vec![0.0; series.len()];
+                let mut sum = vec![0.0; series.len()];
+                let mut sum_sq = vec![0.0; series.len()];
+                kand::ohlcv::bbands::bbands(
+                    series,
+                    BB_PERIOD,
+                    BB_DEV,
+                    BB_DEV,
+                    &mut upper,
+                    &mut middle,
+                    &mut lower,
+                    &mut sma,
+                    &mut variance,
+                    &mut sum,
+                    &mut sum_sq,
+                )
+                .unwrap();
+                let seed_sma = sma[BB_PERIOD - 1];
+                let seed_sum = sum[BB_PERIOD - 1];
+                let seed_sum_sq = sum_sq[BB_PERIOD - 1];
+                bencher.iter(|| {
+                    let mut prev_sma = seed_sma;
+                    let mut prev_sum = seed_sum;
+                    let mut prev_sum_sq = seed_sum_sq;
+                    for idx in BB_PERIOD..series.len() {
+                        let result = kand::ohlcv::bbands::bbands_inc(
+                            series[idx],
+                            prev_sma,
+                            prev_sum,
+                            prev_sum_sq,
+                            series[idx - BB_PERIOD],
+                            BB_PERIOD,
+                            BB_DEV,
+                            BB_DEV,
+                        )
+                        .unwrap();
+                        prev_sma = result.1;
+                        prev_sum = result.4;
+                        prev_sum_sq = result.5;
+                        black_box((result.0, result.1, result.2));
+                    }
+                });
+            },
+        );
+        group.bench_with_input(
+            BenchmarkId::new("kand/batch", len),
+            &series,
+            |bencher, &series| {
+                bencher.iter(|| {
+                    let mut upper = vec![0.0; series.len()];
+                    let mut middle = vec![0.0; series.len()];
+                    let mut lower = vec![0.0; series.len()];
+                    let mut sma = vec![0.0; series.len()];
+                    let mut variance = vec![0.0; series.len()];
+                    let mut sum = vec![0.0; series.len()];
+                    let mut sum_sq = vec![0.0; series.len()];
+                    kand::ohlcv::bbands::bbands(
+                        series,
+                        BB_PERIOD,
+                        BB_DEV,
+                        BB_DEV,
+                        &mut upper,
+                        &mut middle,
+                        &mut lower,
+                        &mut sma,
+                        &mut variance,
+                        &mut sum,
+                        &mut sum_sq,
+                    )
+                    .unwrap();
+                    black_box(&upper);
+                });
+            },
+        );
+        group.bench_with_input(
+            BenchmarkId::new("ta-rs/stream", len),
+            &series,
+            |bencher, &series| {
+                bencher.iter(|| {
+                    let mut ind = ta::indicators::BollingerBands::new(BB_PERIOD, BB_DEV).unwrap();
+                    for &price in series {
+                        black_box(ta::Next::next(&mut ind, price));
+                    }
+                });
+            },
+        );
+    }
+    group.finish();
+}
+
+fn atr_group(crit: &mut Criterion, candles: &[Candle]) {
+    let mut group = crit.benchmark_group("atr_14");
+    for &len in SIZES {
+        let len = len.min(candles.len());
+        let series: &[Candle] = &candles[..len];
+        group.throughput(Throughput::Elements(len as u64));
+
+        group.bench_with_input(
+            BenchmarkId::new("wickra/stream", len),
+            &series,
+            |bencher, &series| {
+                bencher.iter(|| {
+                    let mut ind = Atr::new(ATR_PERIOD).unwrap();
+                    for &candle in series {
+                        black_box(ind.update(candle));
+                    }
+                });
+            },
+        );
+        group.bench_with_input(
+            BenchmarkId::new("wickra/batch", len),
+            &series,
+            |bencher, &series| {
+                // Column extraction is outside the timed loop, mirroring kand's arm.
+                let high: Vec<f64> = series.iter().map(|candle| candle.high).collect();
+                let low: Vec<f64> = series.iter().map(|candle| candle.low).collect();
+                let close: Vec<f64> = series.iter().map(|candle| candle.close).collect();
+                bencher.iter(|| {
+                    let mut ind = Atr::new(ATR_PERIOD).unwrap();
+                    black_box(ind.batch_atr(&high, &low, &close));
+                });
+            },
+        );
+        group.bench_with_input(
+            BenchmarkId::new("kand/stream", len),
+            &series,
+            |bencher, &series| {
+                let high: Vec<f64> = series.iter().map(|candle| candle.high).collect();
+                let low: Vec<f64> = series.iter().map(|candle| candle.low).collect();
+                let close: Vec<f64> = series.iter().map(|candle| candle.close).collect();
+                // Seed prev_atr from kand's batch ATR at the first valid index (= period).
+                let mut atr_out = vec![0.0; series.len()];
+                kand::ohlcv::atr::atr(&high, &low, &close, ATR_PERIOD, &mut atr_out).unwrap();
+                let seed_atr = atr_out[ATR_PERIOD];
+                bencher.iter(|| {
+                    let mut prev_atr = seed_atr;
+                    for idx in ATR_PERIOD + 1..series.len() {
+                        prev_atr = kand::ohlcv::atr::atr_inc(
+                            high[idx],
+                            low[idx],
+                            close[idx - 1],
+                            prev_atr,
+                            ATR_PERIOD,
+                        )
+                        .unwrap();
+                        black_box(prev_atr);
+                    }
+                });
+            },
+        );
+        group.bench_with_input(
+            BenchmarkId::new("kand/batch", len),
+            &series,
+            |bencher, &series| {
+                let high: Vec<f64> = series.iter().map(|candle| candle.high).collect();
+                let low: Vec<f64> = series.iter().map(|candle| candle.low).collect();
+                let close: Vec<f64> = series.iter().map(|candle| candle.close).collect();
+                bencher.iter(|| {
+                    let mut atr_out = vec![0.0; series.len()];
+                    kand::ohlcv::atr::atr(&high, &low, &close, ATR_PERIOD, &mut atr_out).unwrap();
+                    black_box(&atr_out);
+                });
+            },
+        );
+        group.bench_with_input(
+            BenchmarkId::new("ta-rs/stream", len),
+            &series,
+            |bencher, &series| {
+                let items: Vec<ta::DataItem> = series
+                    .iter()
+                    .map(|candle| {
+                        ta::DataItem::builder()
+                            .open(candle.open)
+                            .high(candle.high)
+                            .low(candle.low)
+                            .close(candle.close)
+                            .volume(candle.volume)
+                            .build()
+                            .unwrap()
+                    })
+                    .collect();
+                bencher.iter(|| {
+                    let mut ind = ta::indicators::AverageTrueRange::new(ATR_PERIOD).unwrap();
+                    for item in &items {
+                        black_box(ta::Next::next(&mut ind, item));
+                    }
+                });
+            },
+        );
+    }
+    group.finish();
+}
+
+fn benches(crit: &mut Criterion) {
+    let candles = load_candles();
+    let closes: Vec<f64> = candles.iter().map(|candle| candle.close).collect();
+    sma_group(crit, &closes);
+    ema_group(crit, &closes);
+    rsi_group(crit, &closes);
+    macd_group(crit, &closes);
+    bbands_group(crit, &closes);
+    atr_group(crit, &candles);
+}
+
+criterion_group!(name = cross_lib; config = Criterion::default(); targets = benches);
+criterion_main!(cross_lib);
@@ -0,0 +1,6 @@
+//! Internal cross-library benchmark harness for Wickra.
+//!
+//! This crate is `publish = false`. It exists only to host the Criterion
+//! benchmark in `benches/cross_lib.rs`, which compares Wickra against the
+//! Rust technical-analysis crates `kand`, `ta` (ta-rs) and `yata` on an
+//! identical candle series. It deliberately carries no library code.
@@ -0,0 +1,245 @@
+//! Adaptive CCI — a CCI whose centre line adapts to the efficiency ratio.
+
+use std::collections::VecDeque;
+
+use crate::error::{Error, Result};
+use crate::ohlcv::Candle;
+use crate::traits::Indicator;
+
+/// Adaptive CCI — Lambert's Commodity Channel Index whose centre line is an
+/// **efficiency-ratio-adaptive** moving average of typical price instead of a
+/// plain SMA, so it leads in trends and stays calm in chop.
+///
+/// ```text
+/// TP   = (high + low + close) / 3
+/// ER   = |TP_t − TP_oldest| / Σ |ΔTP| over the window      (0..1)
+/// sc   = ( ER·(2/3 − 2/31) + 2/31 )²
+/// mean += sc·(TP_t − mean)                                  (adaptive centre, seeded with SMA)
+/// MD   = mean(|TP_i − mean|) over the window               (mean deviation)
+/// CCI  = (TP_t − mean) / (0.015 · MD)
+/// ```
+///
+/// The classic [`Cci`](crate::Cci) centres typical price on its simple moving
+/// average; the lag of that SMA delays the oscillator in fast moves. Replacing it
+/// with a KAMA-style adaptive average — driven by Kaufman's efficiency ratio —
+/// lets the centre line accelerate toward price in a clean trend (so the CCI
+/// reaches its `±100` bands sooner) and slow down in noise (fewer false pokes).
+/// The `0.015` scaling keeps Lambert's convention that roughly 70–80% of readings
+/// fall in `[−100, +100]`.
+///
+/// The output is unbounded around `0`; a flat window (zero mean deviation) returns
+/// `0`. The first value lands after `period` inputs; each `update` is O(`period`).
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Candle, Indicator, AdaptiveCci};
+///
+/// let mut indicator = AdaptiveCci::new(20).unwrap();
+/// let mut last = None;
+/// for i in 0..60 {
+///     let base = 100.0 + (f64::from(i) * 0.3).sin() * 5.0;
+///     let c = Candle::new(base, base + 1.0, base - 1.0, base, 1_000.0, 0).unwrap();
+///     last = indicator.update(c);
+/// }
+/// assert!(last.is_some());
+/// ```
+#[derive(Debug, Clone)]
+pub struct AdaptiveCci {
+    period: usize,
+    window: VecDeque<f64>,
+    mean: Option<f64>,
+    last: Option<f64>,
+}
+
+impl AdaptiveCci {
+    /// Construct an adaptive CCI with the given `period`.
+    ///
+    /// # Errors
+    ///
+    /// Returns [`Error::PeriodZero`] if `period == 0` and
+    /// [`Error::InvalidPeriod`] if `period < 2` (the efficiency ratio needs a
+    /// path of at least one step).
+    pub fn new(period: usize) -> Result<Self> {
+        if period == 0 {
+            return Err(Error::PeriodZero);
+        }
+        if period < 2 {
+            return Err(Error::InvalidPeriod {
+                message: "adaptive CCI needs period >= 2",
+            });
+        }
+        Ok(Self {
+            period,
+            window: VecDeque::with_capacity(period),
+            mean: None,
+            last: None,
+        })
+    }
+
+    /// Configured period.
+    pub const fn period(&self) -> usize {
+        self.period
+    }
+
+    /// Current value if available.
+    pub const fn value(&self) -> Option<f64> {
+        self.last
+    }
+}
+
+impl Indicator for AdaptiveCci {
+    type Input = Candle;
+    type Output = f64;
+
+    fn update(&mut self, candle: Candle) -> Option<f64> {
+        let tp = candle.typical_price();
+        if self.window.len() == self.period {
+            self.window.pop_front();
+        }
+        self.window.push_back(tp);
+        if self.window.len() < self.period {
+            return None;
+        }
+        let n = self.period as f64;
+
+        // Efficiency ratio over the window.
+        let oldest = self.window[0];
+        let direction = (tp - oldest).abs();
+        let mut path = 0.0;
+        for pair in self.window.iter().collect::<Vec<_>>().windows(2) {
+            path += (pair[1] - pair[0]).abs();
+        }
+        let er = if path > 0.0 {
+            (direction / path).clamp(0.0, 1.0)
+        } else {
+            0.0
+        };
+        let fast = 2.0 / 3.0;
+        let slow = 2.0 / 31.0;
+        let sc = (er * (fast - slow) + slow).powi(2);
+
+        let mean = match self.mean {
+            None => self.window.iter().sum::<f64>() / n,
+            Some(prev) => prev + sc * (tp - prev),
+        };
+        self.mean = Some(mean);
+
+        let md = self.window.iter().map(|&v| (v - mean).abs()).sum::<f64>() / n;
+        let cci = if md > 0.0 {
+            (tp - mean) / (0.015 * md)
+        } else {
+            0.0
+        };
+        self.last = Some(cci);
+        Some(cci)
+    }
+
+    fn reset(&mut self) {
+        self.window.clear();
+        self.mean = None;
+        self.last = None;
+    }
+
+    fn warmup_period(&self) -> usize {
+        self.period
+    }
+
+    fn is_ready(&self) -> bool {
+        self.last.is_some()
+    }
+
+    fn name(&self) -> &'static str {
+        "AdaptiveCci"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    fn candle(tp: f64) -> Candle {
+        // open=high=low=close=tp -> typical price == tp.
+        Candle::new_unchecked(tp, tp, tp, tp, 1_000.0, 0)
+    }
+
+    #[test]
+    fn rejects_invalid_period() {
+        assert!(matches!(AdaptiveCci::new(0), Err(Error::PeriodZero)));
+        assert!(matches!(
+            AdaptiveCci::new(1),
+            Err(Error::InvalidPeriod { .. })
+        ));
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let c = AdaptiveCci::new(20).unwrap();
+        assert_eq!(c.period(), 20);
+        assert_eq!(c.warmup_period(), 20);
+        assert_eq!(c.name(), "AdaptiveCci");
+        assert!(!c.is_ready());
+        assert_eq!(c.value(), None);
+    }
+
+    #[test]
+    fn first_emission_at_warmup_period() {
+        let mut c = AdaptiveCci::new(4).unwrap();
+        let candles: Vec<Candle> = (0..6).map(|i| candle(100.0 + f64::from(i))).collect();
+        let out = c.batch(&candles);
+        for v in out.iter().take(3) {
+            assert!(v.is_none());
+        }
+        assert!(out[3].is_some());
+    }
+
+    #[test]
+    fn uptrend_is_positive() {
+        let mut c = AdaptiveCci::new(10).unwrap();
+        let candles: Vec<Candle> = (0..40).map(|i| candle(100.0 + f64::from(i))).collect();
+        let last = c.batch(&candles).into_iter().flatten().last().unwrap();
+        assert!(last > 0.0, "uptrend should give positive CCI, got {last}");
+    }
+
+    #[test]
+    fn downtrend_is_negative() {
+        let mut c = AdaptiveCci::new(10).unwrap();
+        let candles: Vec<Candle> = (0..40).map(|i| candle(200.0 - f64::from(i))).collect();
+        let last = c.batch(&candles).into_iter().flatten().last().unwrap();
+        assert!(last < 0.0, "downtrend should give negative CCI, got {last}");
+    }
+
+    #[test]
+    fn flat_window_is_zero() {
+        let mut c = AdaptiveCci::new(5).unwrap();
+        let candles: Vec<Candle> = (0..10).map(|_| candle(100.0)).collect();
+        for v in c.batch(&candles).into_iter().flatten() {
+            assert_relative_eq!(v, 0.0, epsilon = 1e-9);
+        }
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut c = AdaptiveCci::new(5).unwrap();
+        let candles: Vec<Candle> = (0..20).map(|i| candle(100.0 + f64::from(i))).collect();
+        c.batch(&candles);
+        assert!(c.is_ready());
+        c.reset();
+        assert!(!c.is_ready());
+        assert_eq!(c.value(), None);
+        assert_eq!(c.update(candle(100.0)), None);
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let candles: Vec<Candle> = (0..120)
+            .map(|i| candle(100.0 + (f64::from(i) * 0.25).sin() * 9.0))
+            .collect();
+        let batch = AdaptiveCci::new(20).unwrap().batch(&candles);
+        let mut b = AdaptiveCci::new(20).unwrap();
+        let streamed: Vec<_> = candles.iter().map(|x| b.update(*x)).collect();
+        assert_eq!(batch, streamed);
+    }
+}
@@ -0,0 +1,344 @@
+//! Ehlers' Adaptive Laguerre Filter.
+
+use std::collections::VecDeque;
+
+use crate::error::{Error, Result};
+use crate::traits::Indicator;
+
+/// John Ehlers' Adaptive Laguerre Filter — a four-stage Laguerre polynomial
+/// smoother whose damping factor `gamma` is recomputed every bar from how well
+/// the filter is currently tracking price.
+///
+/// The Laguerre cascade is the same one used by [`LaguerreRsi`](crate::LaguerreRsi),
+/// but instead of a fixed `gamma` the filter adapts: it measures the recent
+/// absolute error `|price − filter|`, normalises those errors across a window of
+/// `period` bars to `[0, 1]`, and takes their **median** as `gamma`. When price
+/// is tracking smoothly the errors are small and uniform (low `gamma`, fast
+/// response); when price jumps, the spread of errors widens and `gamma` rises,
+/// slowing the filter to reject the noise.
+///
+/// ```text
+/// diff_t  = |price_t − filter_{t-1}|
+/// over the last `period` diffs:
+///   HH = max(diff),  LL = min(diff)
+///   norm_i = (diff_i − LL) / (HH − LL)      (0 if HH == LL)
+///   gamma  = median(norm)
+/// alpha   = 1 − gamma
+/// L0_t = alpha·price_t + gamma·L0_{t-1}
+/// L1_t = −gamma·L0_t + L0_{t-1} + gamma·L1_{t-1}
+/// L2_t = −gamma·L1_t + L1_{t-1} + gamma·L2_{t-1}
+/// L3_t = −gamma·L2_t + L2_{t-1} + gamma·L3_{t-1}
+/// filter_t = (L0_t + 2·L1_t + 2·L2_t + L3_t) / 6
+/// ```
+///
+/// The output is a smoothed price on the same scale as the input. The first
+/// emission lands once the error window holds `period` values.
+///
+/// Reference: John F. Ehlers, *"Adaptive Laguerre Filter"*, Technical Analysis
+/// of Stocks & Commodities, 2007.
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Indicator, AdaptiveLaguerreFilter};
+///
+/// let mut indicator = AdaptiveLaguerreFilter::new(13).unwrap();
+/// let mut last = None;
+/// for i in 0..80 {
+///     last = indicator.update(100.0 + f64::from(i));
+/// }
+/// assert!(last.is_some());
+/// ```
+#[derive(Debug, Clone)]
+pub struct AdaptiveLaguerreFilter {
+    period: usize,
+    l0: f64,
+    l1: f64,
+    l2: f64,
+    l3: f64,
+    /// Previous filter output, or `None` before the first bar.
+    filter: Option<f64>,
+    /// The last `period` absolute errors `|price − filter|`.
+    diffs: VecDeque<f64>,
+}
+
+impl AdaptiveLaguerreFilter {
+    /// Construct a new adaptive Laguerre filter with the given error-window
+    /// length.
+    ///
+    /// # Errors
+    ///
+    /// Returns [`Error::PeriodZero`] if `period == 0`.
+    pub fn new(period: usize) -> Result<Self> {
+        if period == 0 {
+            return Err(Error::PeriodZero);
+        }
+        Ok(Self {
+            period,
+            l0: 0.0,
+            l1: 0.0,
+            l2: 0.0,
+            l3: 0.0,
+            filter: None,
+            diffs: VecDeque::with_capacity(period),
+        })
+    }
+
+    /// Configured error-window length.
+    pub const fn period(&self) -> usize {
+        self.period
+    }
+
+    /// Current value if the error window is full.
+    pub fn value(&self) -> Option<f64> {
+        if self.diffs.len() == self.period {
+            self.filter
+        } else {
+            None
+        }
+    }
+
+    /// Median of the normalised errors currently in the window. Returns `0.0`
+    /// when every error is equal (e.g. during a constant warmup), which makes
+    /// the filter maximally fast.
+    fn adaptive_gamma(&self) -> f64 {
+        let mut hh = f64::MIN;
+        let mut ll = f64::MAX;
+        for &d in &self.diffs {
+            if d > hh {
+                hh = d;
+            }
+            if d < ll {
+                ll = d;
+            }
+        }
+        let range = hh - ll;
+        if range <= 0.0 {
+            return 0.0;
+        }
+        let mut norm: Vec<f64> = self.diffs.iter().map(|&d| (d - ll) / range).collect();
+        // `total_cmp` never panics — under pathological (e.g. overflowing) fuzz
+        // inputs a normalised error can be non-finite; a total order keeps the
+        // sort sound where `partial_cmp` would return `None`.
+        norm.sort_by(f64::total_cmp);
+        let mid = norm.len() / 2;
+        if norm.len() % 2 == 1 {
+            norm[mid]
+        } else {
+            f64::midpoint(norm[mid - 1], norm[mid])
+        }
+    }
+}
+
+impl Indicator for AdaptiveLaguerreFilter {
+    type Input = f64;
+    type Output = f64;
+
+    fn update(&mut self, price: f64) -> Option<f64> {
+        if !price.is_finite() {
+            return self.value();
+        }
+        // Absolute tracking error against the previous filter (0 on the first
+        // bar, where there is no prior filter value).
+        let diff = self.filter.map_or(0.0, |f| (price - f).abs());
+        if self.diffs.len() == self.period {
+            self.diffs.pop_front();
+        }
+        self.diffs.push_back(diff);
+
+        let gamma = self.adaptive_gamma();
+        let alpha = 1.0 - gamma;
+
+        let l0 = alpha * price + gamma * self.l0;
+        let l1 = -gamma * l0 + self.l0 + gamma * self.l1;
+        let l2 = -gamma * l1 + self.l1 + gamma * self.l2;
+        let l3 = -gamma * l2 + self.l2 + gamma * self.l3;
+        self.l0 = l0;
+        self.l1 = l1;
+        self.l2 = l2;
+        self.l3 = l3;
+
+        let filter = (l0 + 2.0 * l1 + 2.0 * l2 + l3) / 6.0;
+        self.filter = Some(filter);
+        self.value()
+    }
+
+    fn reset(&mut self) {
+        self.l0 = 0.0;
+        self.l1 = 0.0;
+        self.l2 = 0.0;
+        self.l3 = 0.0;
+        self.filter = None;
+        self.diffs.clear();
+    }
+
+    fn warmup_period(&self) -> usize {
+        self.period
+    }
+
+    fn is_ready(&self) -> bool {
+        self.diffs.len() == self.period
+    }
+
+    fn name(&self) -> &'static str {
+        "AdaptiveLaguerre"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    /// Independent reference: replays the exact recurrence from scratch.
+    fn naive(prices: &[f64], period: usize) -> Vec<Option<f64>> {
+        let (mut l0, mut l1, mut l2, mut l3) = (0.0_f64, 0.0_f64, 0.0_f64, 0.0_f64);
+        let mut filter: Option<f64> = None;
+        let mut diffs: Vec<f64> = Vec::new();
+        let mut out = Vec::with_capacity(prices.len());
+        for &price in prices {
+            let diff = filter.map_or(0.0, |f: f64| (price - f).abs());
+            diffs.push(diff);
+            if diffs.len() > period {
+                diffs.remove(0);
+            }
+            let hh = diffs.iter().copied().fold(f64::MIN, f64::max);
+            let ll = diffs.iter().copied().fold(f64::MAX, f64::min);
+            let range = hh - ll;
+            let gamma = if range <= 0.0 {
+                0.0
+            } else {
+                let mut norm: Vec<f64> = diffs.iter().map(|&d| (d - ll) / range).collect();
+                norm.sort_by(|a, b| a.partial_cmp(b).unwrap());
+                let mid = norm.len() / 2;
+                if norm.len() % 2 == 1 {
+                    norm[mid]
+                } else {
+                    f64::midpoint(norm[mid - 1], norm[mid])
+                }
+            };
+            let alpha = 1.0 - gamma;
+            let n0 = alpha * price + gamma * l0;
+            let n1 = -gamma * n0 + l0 + gamma * l1;
+            let n2 = -gamma * n1 + l1 + gamma * l2;
+            let n3 = -gamma * n2 + l2 + gamma * l3;
+            l0 = n0;
+            l1 = n1;
+            l2 = n2;
+            l3 = n3;
+            let f = (n0 + 2.0 * n1 + 2.0 * n2 + n3) / 6.0;
+            filter = Some(f);
+            out.push(if diffs.len() == period { Some(f) } else { None });
+        }
+        out
+    }
+
+    #[test]
+    fn new_rejects_zero_period() {
+        assert!(matches!(
+            AdaptiveLaguerreFilter::new(0),
+            Err(Error::PeriodZero)
+        ));
+    }
+
+    /// Cover the const accessor `period` and the Indicator-impl `warmup_period`
+    /// + `name`.
+    #[test]
+    fn accessors_and_metadata() {
+        let alf = AdaptiveLaguerreFilter::new(13).unwrap();
+        assert_eq!(alf.period(), 13);
+        assert_eq!(alf.warmup_period(), 13);
+        assert_eq!(alf.name(), "AdaptiveLaguerre");
+    }
+
+    #[test]
+    fn warmup_returns_none_until_window_full() {
+        let mut alf = AdaptiveLaguerreFilter::new(3).unwrap();
+        assert_eq!(alf.update(10.0), None);
+        assert_eq!(alf.update(11.0), None);
+        assert!(alf.update(12.0).is_some());
+    }
+
+    #[test]
+    fn constant_series_converges_to_constant() {
+        // Errors are all zero -> gamma 0 -> the 4-stage delay line fills with
+        // the constant and the filter settles on it.
+        let mut alf = AdaptiveLaguerreFilter::new(5).unwrap();
+        let out = alf.batch(&[42.0_f64; 40]);
+        let last = out.iter().rev().flatten().next().unwrap();
+        assert_relative_eq!(*last, 42.0, epsilon = 1e-9);
+    }
+
+    #[test]
+    fn converged_output_stays_within_price_range() {
+        // Once the Laguerre cascade has filled (it cold-starts from zero, so the
+        // first few post-warmup values ramp up toward price), the filter is a
+        // convex blend of recent prices and must stay inside the data range.
+        let prices: Vec<f64> = (0..120)
+            .map(|i| 50.0 + (f64::from(i) * 0.4).sin() * 10.0)
+            .collect();
+        let lo = prices.iter().copied().fold(f64::MAX, f64::min);
+        let hi = prices.iter().copied().fold(f64::MIN, f64::max);
+        let period = 8;
+        let mut alf = AdaptiveLaguerreFilter::new(period).unwrap();
+        for (i, v) in alf.batch(&prices).into_iter().enumerate() {
+            // Skip the cold-start transient (a few multiples of the window).
+            if i < 4 * period {
+                continue;
+            }
+            let v = v.expect("filter is ready well past warmup");
+            assert!(
+                v >= lo - 1e-6 && v <= hi + 1e-6,
+                "filter out of range at {i}"
+            );
+        }
+    }
+
+    #[test]
+    fn matches_naive_recurrence() {
+        let prices: Vec<f64> = (0..80)
+            .map(|i| 100.0 + (f64::from(i) * 0.5).sin() * 8.0 + f64::from(i) * 0.1)
+            .collect();
+        let mut alf = AdaptiveLaguerreFilter::new(10).unwrap();
+        let got = alf.batch(&prices);
+        let want = naive(&prices, 10);
+        for (i, (g, w)) in got.iter().zip(want.iter()).enumerate() {
+            assert_eq!(g.is_some(), w.is_some(), "readiness mismatch at {i}");
+            if let (Some(a), Some(b)) = (g, w) {
+                assert_relative_eq!(*a, *b, epsilon = 1e-9);
+            }
+        }
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut alf = AdaptiveLaguerreFilter::new(5).unwrap();
+        alf.batch(&(1..=40).map(f64::from).collect::<Vec<_>>());
+        assert!(alf.is_ready());
+        alf.reset();
+        assert!(!alf.is_ready());
+        assert_eq!(alf.update(1.0), None);
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let prices: Vec<f64> = (1..=50).map(|i| f64::from(i) * 0.7).collect();
+        let mut a = AdaptiveLaguerreFilter::new(7).unwrap();
+        let mut b = AdaptiveLaguerreFilter::new(7).unwrap();
+        assert_eq!(
+            a.batch(&prices),
+            prices.iter().map(|p| b.update(*p)).collect::<Vec<_>>()
+        );
+    }
+
+    #[test]
+    fn ignores_non_finite_input() {
+        let mut alf = AdaptiveLaguerreFilter::new(3).unwrap();
+        alf.update(10.0);
+        alf.update(11.0);
+        let ready = alf.update(12.0).expect("ready after three inputs");
+        assert_eq!(alf.update(f64::NAN), Some(ready));
+        assert_eq!(alf.update(f64::INFINITY), Some(ready));
+    }
+}
@@ -0,0 +1,296 @@
+//! Adaptive RSI — an RSI whose up/down averaging adapts to the efficiency ratio.
+
+use std::collections::VecDeque;
+
+use crate::error::{Error, Result};
+use crate::traits::Indicator;
+
+/// Adaptive RSI — Wilder's RSI in which the smoothing of the average gain and
+/// average loss **adapts to trendiness** via Kaufman's efficiency ratio, so the
+/// oscillator reacts fast in a clean move and smooths through chop.
+///
+/// ```text
+/// ER     = |price_t − price_{t−period}| / Σ |Δprice| over the window   (efficiency ratio, 0..1)
+/// sc     = ( ER·(2/3 − 2/31) + 2/31 )²                                  (KAMA smoothing constant)
+/// avg_gain += sc·(gain − avg_gain),  avg_loss += sc·(loss − avg_loss)
+/// RSI    = 100 · avg_gain / (avg_gain + avg_loss)
+/// ```
+///
+/// A fixed-period [`Rsi`](crate::Rsi) is a compromise: short periods whip in
+/// ranges, long ones lag in trends. This adaptive form borrows Kaufman's
+/// efficiency ratio (`directional move / total path`) to set the smoothing each
+/// bar — near `1` (a clean trend) the averages track gains and losses almost
+/// immediately; near `0` (noise) they barely move, filtering the chop. The result
+/// is an RSI that is responsive when it should be and quiet when it should be. It
+/// is the efficiency-ratio cousin of Ehlers' cycle-adaptive RSI, which instead
+/// sets the lookback from the measured dominant cycle.
+///
+/// Output is bounded in `[0, 100]`; a flat market returns the neutral `50`. The
+/// first value lands after `period + 1` inputs. Each `update` is O(1).
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Indicator, AdaptiveRsi};
+///
+/// let mut indicator = AdaptiveRsi::new(14).unwrap();
+/// let mut last = None;
+/// for i in 0..60 {
+///     last = indicator.update(100.0 + (f64::from(i) * 0.3).sin() * 5.0);
+/// }
+/// assert!(last.is_some());
+/// ```
+#[derive(Debug, Clone)]
+pub struct AdaptiveRsi {
+    period: usize,
+    prices: VecDeque<f64>,
+    abs_changes: VecDeque<f64>,
+    abs_sum: f64,
+    prev: Option<f64>,
+    seed_gain: f64,
+    seed_loss: f64,
+    seed_count: usize,
+    avg_gain: Option<f64>,
+    avg_loss: Option<f64>,
+    last: Option<f64>,
+}
+
+impl AdaptiveRsi {
+    /// Construct an adaptive RSI with the given efficiency-ratio `period`.
+    ///
+    /// # Errors
+    ///
+    /// Returns [`Error::PeriodZero`] if `period == 0`.
+    pub fn new(period: usize) -> Result<Self> {
+        if period == 0 {
+            return Err(Error::PeriodZero);
+        }
+        Ok(Self {
+            period,
+            prices: VecDeque::with_capacity(period + 1),
+            abs_changes: VecDeque::with_capacity(period),
+            abs_sum: 0.0,
+            prev: None,
+            seed_gain: 0.0,
+            seed_loss: 0.0,
+            seed_count: 0,
+            avg_gain: None,
+            avg_loss: None,
+            last: None,
+        })
+    }
+
+    /// Configured efficiency-ratio period.
+    pub const fn period(&self) -> usize {
+        self.period
+    }
+
+    /// Current value if available.
+    pub const fn value(&self) -> Option<f64> {
+        self.last
+    }
+
+    fn rsi_from_avgs(avg_gain: f64, avg_loss: f64) -> f64 {
+        let denom = avg_gain + avg_loss;
+        if denom == 0.0 {
+            50.0
+        } else {
+            100.0 * (avg_gain / denom)
+        }
+    }
+
+    fn efficiency_ratio(&self, price: f64) -> f64 {
+        let oldest = *self.prices.front().expect("window non-empty");
+        let direction = (price - oldest).abs();
+        if self.abs_sum == 0.0 {
+            0.0
+        } else {
+            (direction / self.abs_sum).clamp(0.0, 1.0)
+        }
+    }
+}
+
+impl Indicator for AdaptiveRsi {
+    type Input = f64;
+    type Output = f64;
+
+    fn update(&mut self, price: f64) -> Option<f64> {
+        if !price.is_finite() {
+            return self.last;
+        }
+        let Some(prev) = self.prev else {
+            self.prev = Some(price);
+            self.prices.push_back(price);
+            return None;
+        };
+        let change = price - prev;
+        self.prev = Some(price);
+        let gain = if change > 0.0 { change } else { 0.0 };
+        let loss = if change < 0.0 { -change } else { 0.0 };
+
+        // Maintain the price window (period + 1) and the |Δ| window (period).
+        self.prices.push_back(price);
+        if self.prices.len() > self.period + 1 {
+            self.prices.pop_front();
+        }
+        if self.abs_changes.len() == self.period {
+            self.abs_sum -= self.abs_changes.pop_front().expect("non-empty");
+        }
+        self.abs_changes.push_back(change.abs());
+        self.abs_sum += change.abs();
+
+        if let (Some(ag), Some(al)) = (self.avg_gain, self.avg_loss) {
+            let er = self.efficiency_ratio(price);
+            let fast = 2.0 / 3.0;
+            let slow = 2.0 / 31.0;
+            let sc = (er * (fast - slow) + slow).powi(2);
+            let new_ag = ag + sc * (gain - ag);
+            let new_al = al + sc * (loss - al);
+            self.avg_gain = Some(new_ag);
+            self.avg_loss = Some(new_al);
+            let v = Self::rsi_from_avgs(new_ag, new_al);
+            self.last = Some(v);
+            return Some(v);
+        }
+
+        self.seed_gain += gain;
+        self.seed_loss += loss;
+        self.seed_count += 1;
+        if self.seed_count == self.period {
+            let ag = self.seed_gain / self.period as f64;
+            let al = self.seed_loss / self.period as f64;
+            self.avg_gain = Some(ag);
+            self.avg_loss = Some(al);
+            let v = Self::rsi_from_avgs(ag, al);
+            self.last = Some(v);
+            return Some(v);
+        }
+        None
+    }
+
+    fn reset(&mut self) {
+        self.prices.clear();
+        self.abs_changes.clear();
+        self.abs_sum = 0.0;
+        self.prev = None;
+        self.seed_gain = 0.0;
+        self.seed_loss = 0.0;
+        self.seed_count = 0;
+        self.avg_gain = None;
+        self.avg_loss = None;
+        self.last = None;
+    }
+
+    fn warmup_period(&self) -> usize {
+        self.period + 1
+    }
+
+    fn is_ready(&self) -> bool {
+        self.last.is_some()
+    }
+
+    fn name(&self) -> &'static str {
+        "AdaptiveRsi"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    #[test]
+    fn rejects_zero_period() {
+        assert!(matches!(AdaptiveRsi::new(0), Err(Error::PeriodZero)));
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let r = AdaptiveRsi::new(14).unwrap();
+        assert_eq!(r.period(), 14);
+        assert_eq!(r.warmup_period(), 15);
+        assert_eq!(r.name(), "AdaptiveRsi");
+        assert!(!r.is_ready());
+        assert_eq!(r.value(), None);
+    }
+
+    #[test]
+    fn first_emission_at_warmup_period() {
+        let mut r = AdaptiveRsi::new(4).unwrap();
+        let out = r.batch(&[1.0, 2.0, 3.0, 4.0, 5.0, 6.0]);
+        for v in out.iter().take(4) {
+            assert!(v.is_none());
+        }
+        assert!(out[4].is_some());
+    }
+
+    #[test]
+    fn pure_uptrend_is_one_hundred() {
+        let mut r = AdaptiveRsi::new(5).unwrap();
+        let last = r
+            .batch(&(1..=40).map(f64::from).collect::<Vec<_>>())
+            .into_iter()
+            .flatten()
+            .last()
+            .unwrap();
+        assert_relative_eq!(last, 100.0, epsilon = 1e-9);
+    }
+
+    #[test]
+    fn flat_market_is_neutral() {
+        let mut r = AdaptiveRsi::new(4).unwrap();
+        let last = r.batch(&[7.0; 20]).into_iter().flatten().last().unwrap();
+        assert_relative_eq!(last, 50.0, epsilon = 1e-9);
+    }
+
+    #[test]
+    fn output_in_range() {
+        let mut r = AdaptiveRsi::new(14).unwrap();
+        for v in r
+            .batch(
+                &(0..200)
+                    .map(|i| 100.0 + (f64::from(i) * 0.3).sin() * 8.0)
+                    .collect::<Vec<_>>(),
+            )
+            .into_iter()
+            .flatten()
+        {
+            assert!((0.0..=100.0).contains(&v));
+        }
+    }
+
+    #[test]
+    fn ignores_non_finite() {
+        let mut r = AdaptiveRsi::new(4).unwrap();
+        let ready = r
+            .batch(&[1.0, 2.0, 3.0, 4.0, 5.0])
+            .into_iter()
+            .flatten()
+            .last()
+            .unwrap();
+        assert_eq!(r.update(f64::NAN), Some(ready));
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut r = AdaptiveRsi::new(4).unwrap();
+        r.batch(&(1..=20).map(f64::from).collect::<Vec<_>>());
+        assert!(r.is_ready());
+        r.reset();
+        assert!(!r.is_ready());
+        assert_eq!(r.value(), None);
+        assert_eq!(r.update(1.0), None);
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let xs: Vec<f64> = (0..120)
+            .map(|i| 100.0 + (f64::from(i) * 0.25).sin() * 9.0)
+            .collect();
+        let batch = AdaptiveRsi::new(14).unwrap().batch(&xs);
+        let mut b = AdaptiveRsi::new(14).unwrap();
+        let streamed: Vec<_> = xs.iter().map(|x| b.update(*x)).collect();
+        assert_eq!(batch, streamed);
+    }
+}
@@ -0,0 +1,239 @@
+//! Amihud Illiquidity — average price impact per unit traded value.
+
+use std::collections::VecDeque;
+
+use crate::microstructure::Trade;
+use crate::traits::Indicator;
+use crate::{Error, Result};
+
+/// Amihud Illiquidity — the average absolute log return per unit of traded
+/// value over the last `period` trades (Amihud, 2002).
+///
+/// ```text
+/// rₜ      = ln(priceₜ / priceₜ₋₁)
+/// ILLIQₜ  = |rₜ| / (priceₜ · sizeₜ)        (return per dollar of volume)
+/// Amihud  = mean of ILLIQ over the last `period` trades
+/// ```
+///
+/// Amihud's measure captures how much the price moves for a given amount of
+/// traded value: a **high** reading means small volume already shifts the price
+/// a lot (an illiquid, easily-moved market), a **low** reading means it takes
+/// large volume to move the price (a deep, liquid market). It is the workhorse
+/// cross-sectional liquidity proxy in market-microstructure research.
+///
+/// `Input = Trade`. Trades with zero size carry no traded value and are skipped
+/// (the ratio is undefined); the last value is returned and state is untouched.
+/// The first valid trade only seeds the reference price.
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Indicator, Side, Trade, AmihudIlliquidity};
+///
+/// let mut amihud = AmihudIlliquidity::new(20).unwrap();
+/// assert_eq!(amihud.update(Trade::new(100.0, 5.0, Side::Buy, 0).unwrap()), None);
+/// ```
+#[derive(Debug, Clone)]
+pub struct AmihudIlliquidity {
+    period: usize,
+    prev_price: Option<f64>,
+    window: VecDeque<f64>,
+    sum: f64,
+    last: Option<f64>,
+}
+
+impl AmihudIlliquidity {
+    /// Construct a new Amihud Illiquidity over the given trade window.
+    ///
+    /// # Errors
+    /// Returns [`Error::PeriodZero`] if `period == 0`.
+    pub fn new(period: usize) -> Result<Self> {
+        if period == 0 {
+            return Err(Error::PeriodZero);
+        }
+        Ok(Self {
+            period,
+            prev_price: None,
+            window: VecDeque::with_capacity(period),
+            sum: 0.0,
+            last: None,
+        })
+    }
+
+    /// Configured period.
+    pub const fn period(&self) -> usize {
+        self.period
+    }
+}
+
+impl Indicator for AmihudIlliquidity {
+    type Input = Trade;
+    type Output = f64;
+
+    fn update(&mut self, trade: Trade) -> Option<f64> {
+        // A zero-size trade has no traded value: the ratio is undefined, so the
+        // trade is skipped without touching the reference price.
+        if trade.size == 0.0 {
+            return self.last;
+        }
+        let Some(prev) = self.prev_price else {
+            self.prev_price = Some(trade.price);
+            return None;
+        };
+        self.prev_price = Some(trade.price);
+        // `prev` and `trade.price` are both finite and strictly positive
+        // (enforced by `Trade::new`), so the log return is well-defined and the
+        // traded value is strictly positive.
+        let ret = (trade.price / prev).ln().abs();
+        let illiq = ret / (trade.price * trade.size);
+        if self.window.len() == self.period {
+            let old = self.window.pop_front().expect("window is non-empty");
+            self.sum -= old;
+        }
+        self.window.push_back(illiq);
+        self.sum += illiq;
+        if self.window.len() < self.period {
+            return None;
+        }
+        let value = self.sum / self.period as f64;
+        self.last = Some(value);
+        Some(value)
+    }
+
+    fn reset(&mut self) {
+        self.prev_price = None;
+        self.window.clear();
+        self.sum = 0.0;
+        self.last = None;
+    }
+
+    fn warmup_period(&self) -> usize {
+        self.period + 1
+    }
+
+    fn is_ready(&self) -> bool {
+        self.last.is_some()
+    }
+
+    fn name(&self) -> &'static str {
+        "AmihudIlliquidity"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::microstructure::Side;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    fn trade(price: f64, size: f64) -> Trade {
+        Trade::new(price, size, Side::Buy, 0).unwrap()
+    }
+
+    #[test]
+    fn rejects_zero_period() {
+        assert!(matches!(AmihudIlliquidity::new(0), Err(Error::PeriodZero)));
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let a = AmihudIlliquidity::new(20).unwrap();
+        assert_eq!(a.period(), 20);
+        assert_eq!(a.warmup_period(), 21);
+        assert_eq!(a.name(), "AmihudIlliquidity");
+        assert!(!a.is_ready());
+    }
+
+    #[test]
+    fn known_value() {
+        // period 1. Seed at 100, then 101 with size 10:
+        // |ln(101/100)| / (101 * 10).
+        let mut a = AmihudIlliquidity::new(1).unwrap();
+        assert_eq!(a.update(trade(100.0, 10.0)), None);
+        let out = a.update(trade(101.0, 10.0)).unwrap();
+        let expected = (101.0_f64 / 100.0).ln().abs() / (101.0 * 10.0);
+        assert_relative_eq!(out, expected, epsilon = 1e-15);
+    }
+
+    #[test]
+    fn higher_for_thinner_volume() {
+        // Same price move on smaller volume => larger illiquidity reading.
+        let thin = {
+            let mut a = AmihudIlliquidity::new(1).unwrap();
+            a.update(trade(100.0, 1.0));
+            a.update(trade(101.0, 1.0)).unwrap()
+        };
+        let thick = {
+            let mut a = AmihudIlliquidity::new(1).unwrap();
+            a.update(trade(100.0, 1000.0));
+            a.update(trade(101.0, 1000.0)).unwrap()
+        };
+        assert!(thin > thick, "thin {thin} should exceed thick {thick}");
+    }
+
+    #[test]
+    fn flat_price_is_zero() {
+        let mut a = AmihudIlliquidity::new(5).unwrap();
+        for v in a.batch(&[trade(100.0, 3.0); 20]).into_iter().flatten() {
+            assert_relative_eq!(v, 0.0, epsilon = 1e-15);
+        }
+    }
+
+    #[test]
+    fn skips_zero_size_trades() {
+        let mut a = AmihudIlliquidity::new(1).unwrap();
+        a.update(trade(100.0, 10.0));
+        let baseline = a.update(trade(101.0, 10.0)).unwrap();
+        // A zero-size trade is ignored; the previous reference price is kept.
+        assert_eq!(a.update(trade(200.0, 0.0)), Some(baseline));
+        // The next real trade still references price 101, not 200.
+        let mut control = a.clone();
+        let after = a.update(trade(102.0, 10.0)).unwrap();
+        assert_eq!(control.update(trade(102.0, 10.0)).unwrap(), after);
+    }
+
+    #[test]
+    fn output_is_non_negative() {
+        let mut a = AmihudIlliquidity::new(10).unwrap();
+        let trades: Vec<Trade> = (0..100)
+            .map(|i| {
+                trade(
+                    100.0 + (f64::from(i) * 0.3).sin() * 5.0,
+                    1.0 + f64::from(i % 7),
+                )
+            })
+            .collect();
+        for v in a.batch(&trades).into_iter().flatten() {
+            assert!(v >= 0.0, "illiquidity must be non-negative, got {v}");
+        }
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut a = AmihudIlliquidity::new(5).unwrap();
+        for i in 0..20 {
+            a.update(trade(100.0 + f64::from(i), 2.0));
+        }
+        assert!(a.is_ready());
+        a.reset();
+        assert!(!a.is_ready());
+        assert_eq!(a.update(trade(100.0, 1.0)), None);
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let trades: Vec<Trade> = (0..80)
+            .map(|i| {
+                trade(
+                    100.0 + (f64::from(i) * 0.25).sin() * 4.0,
+                    1.0 + f64::from(i % 5),
+                )
+            })
+            .collect();
+        let batch = AmihudIlliquidity::new(14).unwrap().batch(&trades);
+        let mut b = AmihudIlliquidity::new(14).unwrap();
+        let streamed: Vec<_> = trades.iter().map(|t| b.update(*t)).collect();
+        assert_eq!(batch, streamed);
+    }
+}
@@ -0,0 +1,353 @@
+//! Andrews Pitchfork — median line and parallels off the last three swing pivots.
+
+use std::collections::VecDeque;
+
+use crate::error::{Error, Result};
+use crate::ohlcv::Candle;
+use crate::traits::Indicator;
+
+/// Output of [`AndrewsPitchfork`]: the three pitchfork lines projected to the
+/// current bar.
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub struct AndrewsPitchforkOutput {
+    /// The median line — from the handle pivot through the midpoint of the other two.
+    pub median: f64,
+    /// The upper parallel (through the higher of the two anchor pivots).
+    pub upper: f64,
+    /// The lower parallel (through the lower of the two anchor pivots).
+    pub lower: f64,
+}
+
+/// A confirmed swing pivot: its bar index and price.
+#[derive(Debug, Clone, Copy)]
+struct Pivot {
+    index: f64,
+    price: f64,
+    is_high: bool,
+}
+
+/// Andrews Pitchfork — Alan Andrews' median-line tool drawn from the three most
+/// recent **swing pivots**, projected forward to the current bar.
+///
+/// ```text
+/// detect alternating swing highs/lows with a `strength`-bar fractal
+/// P0 = handle (oldest of the last three), P1, P2 = the next two
+/// M  = midpoint of P1 and P2
+/// median(t) = P0 + slope·(t − t0)          slope = (M − P0) / (M_t − t0)
+/// upper / lower = median(t) offset by the vertical gap to the higher / lower anchor
+/// ```
+///
+/// The pitchfork projects a "fork" of three parallel lines: a central **median
+/// line** drawn from a starting pivot through the midpoint of a later swing, plus
+/// two parallels passing through that swing's high and low. Price tends to
+/// oscillate around the median line and find support/resistance at the parallels.
+/// This streaming version detects the pivots automatically with a symmetric
+/// fractal of half-width `strength` (so each pivot is confirmed `strength` bars
+/// late) and keeps the three most recent alternating swings.
+///
+/// Because it depends on swing structure, readiness is **data-dependent**: the
+/// first output appears once three alternating pivots have been confirmed.
+/// `warmup_period` returns the minimum bars to confirm a single pivot. Each
+/// `update` is O(`strength`).
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Candle, Indicator, AndrewsPitchfork};
+///
+/// let mut indicator = AndrewsPitchfork::new(2).unwrap();
+/// let mut last = None;
+/// for i in 0..120 {
+///     let base = 100.0 + (f64::from(i) * 0.4).sin() * 10.0;
+///     let c = Candle::new(base, base + 1.0, base - 1.0, base, 1_000.0, 0).unwrap();
+///     last = indicator.update(c);
+/// }
+/// // A swinging series eventually establishes a pitchfork.
+/// let _ = last;
+/// ```
+#[derive(Debug, Clone)]
+pub struct AndrewsPitchfork {
+    strength: usize,
+    window: VecDeque<Candle>,
+    pivots: Vec<Pivot>,
+    count: usize,
+    last: Option<AndrewsPitchforkOutput>,
+}
+
+impl AndrewsPitchfork {
+    /// Construct an Andrews Pitchfork with the given fractal `strength` (bars on
+    /// each side of a pivot).
+    ///
+    /// # Errors
+    ///
+    /// Returns [`Error::PeriodZero`] if `strength == 0`.
+    pub fn new(strength: usize) -> Result<Self> {
+        if strength == 0 {
+            return Err(Error::PeriodZero);
+        }
+        Ok(Self {
+            strength,
+            window: VecDeque::with_capacity(2 * strength + 1),
+            pivots: Vec::new(),
+            count: 0,
+            last: None,
+        })
+    }
+
+    /// Configured fractal strength.
+    pub const fn strength(&self) -> usize {
+        self.strength
+    }
+
+    /// Current value if available.
+    pub const fn value(&self) -> Option<AndrewsPitchforkOutput> {
+        self.last
+    }
+
+    /// Record a freshly confirmed pivot, keeping the last three alternating swings.
+    fn record_pivot(&mut self, pivot: Pivot) {
+        if let Some(last) = self.pivots.last_mut() {
+            if last.is_high == pivot.is_high {
+                // Same kind: keep the more extreme one (and its index).
+                let more_extreme = if pivot.is_high {
+                    pivot.price > last.price
+                } else {
+                    pivot.price < last.price
+                };
+                if more_extreme {
+                    *last = pivot;
+                }
+                return;
+            }
+        }
+        self.pivots.push(pivot);
+        if self.pivots.len() > 3 {
+            self.pivots.remove(0);
+        }
+    }
+
+    fn project(&self, tc: f64) -> Option<AndrewsPitchforkOutput> {
+        let [p0, p1, p2] = self.pivots.as_slice() else {
+            return None;
+        };
+        let mid_t = f64::midpoint(p1.index, p2.index);
+        let mid_p = f64::midpoint(p1.price, p2.price);
+        let slope = (mid_p - p0.price) / (mid_t - p0.index);
+        let median = p0.price + slope * (tc - p0.index);
+        let off1 = p1.price - (p0.price + slope * (p1.index - p0.index));
+        let off2 = p2.price - (p0.price + slope * (p2.index - p0.index));
+        Some(AndrewsPitchforkOutput {
+            median,
+            upper: median + off1.max(off2),
+            lower: median + off1.min(off2),
+        })
+    }
+}
+
+impl Indicator for AndrewsPitchfork {
+    type Input = Candle;
+    type Output = AndrewsPitchforkOutput;
+
+    fn update(&mut self, candle: Candle) -> Option<AndrewsPitchforkOutput> {
+        self.count += 1;
+        let span = 2 * self.strength + 1;
+        if self.window.len() == span {
+            self.window.pop_front();
+        }
+        self.window.push_back(candle);
+        if self.window.len() == span {
+            let center = self.window[self.strength];
+            let is_high = self
+                .window
+                .iter()
+                .enumerate()
+                .all(|(i, c)| i == self.strength || c.high < center.high);
+            let is_low = self
+                .window
+                .iter()
+                .enumerate()
+                .all(|(i, c)| i == self.strength || c.low > center.low);
+            // Absolute index of the center bar (1-based count minus the right span).
+            let center_index = (self.count - 1 - self.strength) as f64;
+            if is_high && !is_low {
+                self.record_pivot(Pivot {
+                    index: center_index,
+                    price: center.high,
+                    is_high: true,
+                });
+            } else if is_low && !is_high {
+                self.record_pivot(Pivot {
+                    index: center_index,
+                    price: center.low,
+                    is_high: false,
+                });
+            }
+        }
+        let tc = (self.count - 1) as f64;
+        if let Some(out) = self.project(tc) {
+            self.last = Some(out);
+            return Some(out);
+        }
+        None
+    }
+
+    fn reset(&mut self) {
+        self.window.clear();
+        self.pivots.clear();
+        self.count = 0;
+        self.last = None;
+    }
+
+    fn warmup_period(&self) -> usize {
+        2 * self.strength + 1
+    }
+
+    fn is_ready(&self) -> bool {
+        self.last.is_some()
+    }
+
+    fn name(&self) -> &'static str {
+        "AndrewsPitchfork"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+
+    fn c(high: f64, low: f64) -> Candle {
+        Candle::new_unchecked(
+            f64::midpoint(high, low),
+            high,
+            low,
+            f64::midpoint(high, low),
+            1_000.0,
+            0,
+        )
+    }
+
+    /// A clean zig-zag that prints alternating swing highs and lows.
+    fn zigzag() -> Vec<Candle> {
+        let mut out = Vec::new();
+        for i in 0..120 {
+            let base = 100.0 + (f64::from(i) * 0.5).sin() * 10.0;
+            out.push(c(base + 1.0, base - 1.0));
+        }
+        out
+    }
+
+    #[test]
+    fn rejects_zero_strength() {
+        assert!(matches!(AndrewsPitchfork::new(0), Err(Error::PeriodZero)));
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let p = AndrewsPitchfork::new(2).unwrap();
+        assert_eq!(p.strength(), 2);
+        assert_eq!(p.warmup_period(), 5);
+        assert_eq!(p.name(), "AndrewsPitchfork");
+        assert!(!p.is_ready());
+        assert_eq!(p.value(), None);
+    }
+
+    #[test]
+    fn none_before_three_pivots() {
+        let mut p = AndrewsPitchfork::new(2).unwrap();
+        // Too few bars to ever confirm three alternating pivots.
+        let out = p.batch(&[c(101.0, 99.0), c(102.0, 100.0), c(101.0, 99.0)]);
+        assert!(out.iter().all(Option::is_none));
+    }
+
+    #[test]
+    fn eventually_emits_on_swings() {
+        let mut p = AndrewsPitchfork::new(2).unwrap();
+        let out = p.batch(&zigzag());
+        assert!(
+            out.iter().any(Option::is_some),
+            "a swinging series should form a pitchfork"
+        );
+        assert!(p.is_ready());
+    }
+
+    #[test]
+    fn upper_at_or_above_lower() {
+        let mut p = AndrewsPitchfork::new(2).unwrap();
+        for o in p.batch(&zigzag()).into_iter().flatten() {
+            assert!(
+                o.upper >= o.lower,
+                "upper {} below lower {}",
+                o.upper,
+                o.lower
+            );
+        }
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut p = AndrewsPitchfork::new(2).unwrap();
+        p.batch(&zigzag());
+        assert!(p.is_ready());
+        p.reset();
+        assert!(!p.is_ready());
+        assert_eq!(p.value(), None);
+        assert_eq!(p.strength(), 2);
+    }
+
+    #[test]
+    fn record_pivot_keeps_more_extreme_same_kind() {
+        let mut p = AndrewsPitchfork::new(2).unwrap();
+        p.record_pivot(Pivot {
+            index: 0.0,
+            price: 100.0,
+            is_high: true,
+        });
+        // A higher high of the same kind replaces the stored one.
+        p.record_pivot(Pivot {
+            index: 1.0,
+            price: 105.0,
+            is_high: true,
+        });
+        assert_eq!(p.pivots.len(), 1);
+        assert_eq!(p.pivots[0].price, 105.0);
+        // A lower high of the same kind is ignored.
+        p.record_pivot(Pivot {
+            index: 2.0,
+            price: 102.0,
+            is_high: true,
+        });
+        assert_eq!(p.pivots.len(), 1);
+        assert_eq!(p.pivots[0].price, 105.0);
+        // A low pivot of the other kind is appended.
+        p.record_pivot(Pivot {
+            index: 3.0,
+            price: 90.0,
+            is_high: false,
+        });
+        assert_eq!(p.pivots.len(), 2);
+        // A lower low of the same kind replaces the stored low.
+        p.record_pivot(Pivot {
+            index: 4.0,
+            price: 85.0,
+            is_high: false,
+        });
+        assert_eq!(p.pivots[1].price, 85.0);
+        // A higher low of the same kind is ignored.
+        p.record_pivot(Pivot {
+            index: 5.0,
+            price: 88.0,
+            is_high: false,
+        });
+        assert_eq!(p.pivots[1].price, 85.0);
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let candles = zigzag();
+        let batch = AndrewsPitchfork::new(2).unwrap().batch(&candles);
+        let mut b = AndrewsPitchfork::new(2).unwrap();
+        let streamed: Vec<_> = candles.iter().map(|x| b.update(*x)).collect();
+        assert_eq!(batch, streamed);
+    }
+}
@@ -28,9 +28,17 @@ use crate::traits::Indicator;
 #[derive(Debug, Clone)]
 pub struct Atr {
    period: usize,
+    /// `period - 1` as `f64`, precomputed for the Wilder smoothing step.
+    n_minus_1: f64,
+    /// `1 / period`, precomputed so the per-tick smoothing multiplies instead of
+    /// divides.
+    inv_period: f64,
    prev_close: Option<f64>,
    seed_buf: Vec<f64>,
-    avg: Option<f64>,
+    /// Smoothed ATR, valid once `seeded` is set. Bare `f64` + flag rather than
+    /// `Option<f64>` so the hot recurrence avoids an enum-tag read per tick.
+    avg: f64,
+    seeded: bool,
 }

 impl Atr {
@@ -45,9 +53,12 @@ impl Atr {
        }
        Ok(Self {
            period,
+            n_minus_1: (period - 1) as f64,
+            inv_period: 1.0 / period as f64,
            prev_close: None,
            seed_buf: Vec::with_capacity(period),
-            avg: None,
+            avg: 0.0,
+            seeded: false,
        })
    }

@@ -58,7 +69,72 @@ impl Atr {

    /// Current value if available.
    pub const fn value(&self) -> Option<f64> {
-        self.avg
+        if self.seeded {
+            Some(self.avg)
+        } else {
+            None
+        }
+    }
+
+    /// Vectorized batch over raw high/low/close columns: one `f64` per bar
+    /// (`NaN` during warmup). The caller guarantees the three slices are equal
+    /// length and finite with valid OHLC ordering (the binding validates once up
+    /// front); ATR only reads high, low and the previous close.
+    ///
+    /// For a fresh indicator long enough to seed (`n >= period`) it runs the
+    /// true-range seed once and then the bare Wilder recurrence in a tight loop —
+    /// no per-bar `Candle` construction/validation, no `Option`, identical
+    /// division at the seed and `mul_add` afterwards, so the result is
+    /// *bit-for-bit* equal to replaying `update` over the same candles. Shorter
+    /// or non-fresh inputs defer to an exact `update` replay.
+    pub fn batch_atr(&mut self, high: &[f64], low: &[f64], close: &[f64]) -> Vec<f64> {
+        let p = self.period;
+        let n = high.len();
+        if self.seeded || !self.seed_buf.is_empty() || self.prev_close.is_some() || n < p {
+            let mut out = vec![f64::NAN; n];
+            for i in 0..n {
+                let candle = Candle::new_unchecked(close[i], high[i], low[i], close[i], 0.0, 0);
+                if let Some(v) = self.update(candle) {
+                    out[i] = v;
+                }
+            }
+            return out;
+        }
+
+        // Warmup `[0, p-1)` is `NaN`; the first ATR is emitted at index `p - 1`.
+        let mut out = vec![f64::NAN; p - 1];
+        out.reserve(n - (p - 1));
+        // Seed: mean of the first `period` true ranges. TR₀ has no previous close.
+        let mut prev_close = close[0];
+        let mut sum_tr = high[0] - low[0];
+        self.seed_buf.push(sum_tr);
+        for i in 1..p {
+            let (h, l) = (high[i], low[i]);
+            let tr = (h - l)
+                .max((h - prev_close).abs())
+                .max((l - prev_close).abs());
+            prev_close = close[i];
+            self.seed_buf.push(tr);
+            sum_tr += tr;
+        }
+        let mut avg = sum_tr / p as f64;
+        out.push(avg);
+        // Steady state: Wilder smoothing, reciprocal hoisted out of the loop.
+        for i in p..n {
+            let (h, l) = (high[i], low[i]);
+            let tr = (h - l)
+                .max((h - prev_close).abs())
+                .max((l - prev_close).abs());
+            prev_close = close[i];
+            avg = avg.mul_add(self.n_minus_1, tr) * self.inv_period;
+            out.push(avg);
+        }
+
+        // Leave state where a full `update` replay would (seeded; seed_buf retained).
+        self.prev_close = Some(prev_close);
+        self.avg = avg;
+        self.seeded = true;
+        out
    }
 }

@@ -70,17 +146,18 @@ impl Indicator for Atr {
        let tr = candle.true_range(self.prev_close);
        self.prev_close = Some(candle.close);

-        if let Some(avg) = self.avg {
-            let n = self.period as f64;
-            let new_avg = avg.mul_add(n - 1.0, tr) / n;
-            self.avg = Some(new_avg);
+        if self.seeded {
+            // Wilder smoothing with the reciprocal hoisted out of the hot path.
+            let new_avg = self.avg.mul_add(self.n_minus_1, tr) * self.inv_period;
+            self.avg = new_avg;
            return Some(new_avg);
        }

        self.seed_buf.push(tr);
        if self.seed_buf.len() == self.period {
            let seed = self.seed_buf.iter().copied().sum::<f64>() / self.period as f64;
-            self.avg = Some(seed);
+            self.avg = seed;
+            self.seeded = true;
            return Some(seed);
        }
        None
@@ -89,7 +166,8 @@ impl Indicator for Atr {
    fn reset(&mut self) {
        self.prev_close = None;
        self.seed_buf.clear();
-        self.avg = None;
+        self.avg = 0.0;
+        self.seeded = false;
    }

    fn warmup_period(&self) -> usize {
@@ -97,7 +175,7 @@ impl Indicator for Atr {
    }

    fn is_ready(&self) -> bool {
-        self.avg.is_some()
+        self.seeded
    }

    fn name(&self) -> &'static str {
@@ -249,6 +327,81 @@ mod tests {
        }
    }

+    fn bits_eq(a: &[f64], b: &[f64]) -> bool {
+        a.len() == b.len()
+            && a.iter()
+                .zip(b)
+                .all(|(x, y)| x == y || (x.is_nan() && y.is_nan()))
+    }
+
+    fn atr_replay(period: usize, high: &[f64], low: &[f64], close: &[f64]) -> Vec<f64> {
+        let mut a = Atr::new(period).unwrap();
+        (0..high.len())
+            .map(|i| {
+                let candle = Candle::new_unchecked(close[i], high[i], low[i], close[i], 0.0, 0);
+                a.update(candle).unwrap_or(f64::NAN)
+            })
+            .collect()
+    }
+
+    /// Valid OHLC columns from a wandering base price.
+    fn columns(n: usize) -> (Vec<f64>, Vec<f64>, Vec<f64>) {
+        let base: Vec<f64> = (0..n)
+            .map(|i| (f64::from(u32::try_from(i).unwrap()) * 0.3).sin() * 5.0 + 100.0)
+            .collect();
+        let high = base.iter().map(|b| b + 1.0).collect();
+        let low = base.iter().map(|b| b - 1.0).collect();
+        (high, low, base)
+    }
+
+    #[test]
+    fn batch_atr_fast_path_is_bit_identical() {
+        let (high, low, close) = columns(300);
+        let mut atr = Atr::new(14).unwrap();
+        let got = atr.batch_atr(&high, &low, &close);
+        assert!(bits_eq(&got, &atr_replay(14, &high, &low, &close)));
+        let mut ref_atr = Atr::new(14).unwrap();
+        for i in 0..high.len() {
+            ref_atr.update(Candle::new_unchecked(
+                close[i], high[i], low[i], close[i], 0.0, 0,
+            ));
+        }
+        let next = Candle::new_unchecked(101.0, 102.0, 100.0, 101.0, 0.0, 0);
+        assert_eq!(atr.update(next), ref_atr.update(next));
+    }
+
+    #[test]
+    fn batch_atr_falls_back_when_not_fresh() {
+        let (high, low, close) = columns(40);
+        let mut atr = Atr::new(14).unwrap();
+        atr.update(Candle::new_unchecked(
+            close[0], high[0], low[0], close[0], 0.0, 0,
+        ));
+        let mut ref_atr = Atr::new(14).unwrap();
+        ref_atr.update(Candle::new_unchecked(
+            close[0], high[0], low[0], close[0], 0.0, 0,
+        ));
+        let want: Vec<f64> = (0..high.len())
+            .map(|i| {
+                ref_atr
+                    .update(Candle::new_unchecked(
+                        close[i], high[i], low[i], close[i], 0.0, 0,
+                    ))
+                    .unwrap_or(f64::NAN)
+            })
+            .collect();
+        assert!(bits_eq(&atr.batch_atr(&high, &low, &close), &want));
+    }
+
+    #[test]
+    fn batch_atr_sub_period_slice_falls_back() {
+        let (high, low, close) = columns(5);
+        let mut atr = Atr::new(14).unwrap();
+        let got = atr.batch_atr(&high, &low, &close);
+        assert!(bits_eq(&got, &atr_replay(14, &high, &low, &close)));
+        assert!(got.iter().all(|x| x.is_nan()));
+    }
+
    proptest::proptest! {
        #![proptest_config(proptest::test_runner::Config::with_cases(48))]
        #[test]
@@ -0,0 +1,279 @@
+//! ATR Ratchet (Kaufman) — a trailing stop that creeps toward price each bar.
+
+use crate::error::{Error, Result};
+use crate::indicators::atr::Atr;
+use crate::ohlcv::Candle;
+use crate::traits::Indicator;
+
+/// Output of [`AtrRatchet`]: the active stop level and the trend direction.
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub struct AtrRatchetOutput {
+    /// The ratchet stop level — below price when long, above price when short.
+    pub value: f64,
+    /// Trend direction: `+1.0` long, `-1.0` short.
+    pub direction: f64,
+}
+
+/// ATR Ratchet — Perry Kaufman's time-based volatility stop that tightens by a
+/// fixed fraction of ATR **every bar**, whether or not price moves.
+///
+/// ```text
+/// on entry (long):   stop = close − start_mult · ATR
+/// each later bar:     stop = stop + increment · ATR    (ratchets toward price)
+/// flip to short when  close < stop, reseeding stop = close + start_mult · ATR
+/// ```
+///
+/// Most trailing stops only move when price makes a new extreme. Kaufman's ratchet
+/// instead advances the stop a little each bar — `increment · ATR` — so a trade
+/// that stalls is squeezed out over time even in a flat market. The initial
+/// distance (`start_mult · ATR`) gives the position room to breathe; the per-bar
+/// `increment` controls how aggressively the leash shortens. When price closes
+/// through the stop the system reverses and reseeds at the full initial distance.
+///
+/// The first stop lands once ATR is ready (`atr_period` inputs). Each `update` is
+/// O(1).
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Candle, Indicator, AtrRatchet};
+///
+/// let mut indicator = AtrRatchet::new(14, 4.0, 0.1).unwrap();
+/// let mut last = None;
+/// for i in 0..60 {
+///     let base = 100.0 + f64::from(i);
+///     let c = Candle::new(base, base + 2.0, base - 2.0, base + 1.0, 1_000.0, 0).unwrap();
+///     last = indicator.update(c);
+/// }
+/// assert!(last.is_some());
+/// ```
+#[derive(Debug, Clone)]
+pub struct AtrRatchet {
+    atr: Atr,
+    atr_period: usize,
+    start_mult: f64,
+    increment: f64,
+    direction: f64,
+    stop: f64,
+    last: Option<AtrRatchetOutput>,
+}
+
+impl AtrRatchet {
+    /// Construct an ATR Ratchet stop.
+    ///
+    /// # Errors
+    ///
+    /// Returns [`Error::PeriodZero`] if `atr_period == 0` and
+    /// [`Error::NonPositiveMultiplier`] if `start_mult` or `increment` is not
+    /// finite and positive.
+    pub fn new(atr_period: usize, start_mult: f64, increment: f64) -> Result<Self> {
+        if !start_mult.is_finite()
+            || start_mult <= 0.0
+            || !increment.is_finite()
+            || increment <= 0.0
+        {
+            return Err(Error::NonPositiveMultiplier);
+        }
+        Ok(Self {
+            atr: Atr::new(atr_period)?,
+            atr_period,
+            start_mult,
+            increment,
+            direction: 0.0,
+            stop: 0.0,
+            last: None,
+        })
+    }
+
+    /// Configured `(atr_period, start_mult, increment)`.
+    pub const fn params(&self) -> (usize, f64, f64) {
+        (self.atr_period, self.start_mult, self.increment)
+    }
+
+    /// Current value if available.
+    pub const fn value(&self) -> Option<AtrRatchetOutput> {
+        self.last
+    }
+}
+
+impl Indicator for AtrRatchet {
+    type Input = Candle;
+    type Output = AtrRatchetOutput;
+
+    fn update(&mut self, candle: Candle) -> Option<AtrRatchetOutput> {
+        let atr = self.atr.update(candle)?;
+        let close = candle.close;
+
+        if self.direction == 0.0 {
+            self.direction = 1.0;
+            self.stop = close - self.start_mult * atr;
+        } else if self.direction > 0.0 {
+            self.stop += self.increment * atr;
+            if close < self.stop {
+                self.direction = -1.0;
+                self.stop = close + self.start_mult * atr;
+            }
+        } else {
+            self.stop -= self.increment * atr;
+            if close > self.stop {
+                self.direction = 1.0;
+                self.stop = close - self.start_mult * atr;
+            }
+        }
+
+        let out = AtrRatchetOutput {
+            value: self.stop,
+            direction: self.direction,
+        };
+        self.last = Some(out);
+        Some(out)
+    }
+
+    fn reset(&mut self) {
+        self.atr.reset();
+        self.direction = 0.0;
+        self.stop = 0.0;
+        self.last = None;
+    }
+
+    fn warmup_period(&self) -> usize {
+        self.atr_period
+    }
+
+    fn is_ready(&self) -> bool {
+        self.last.is_some()
+    }
+
+    fn name(&self) -> &'static str {
+        "AtrRatchet"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+
+    fn c(high: f64, low: f64, close: f64) -> Candle {
+        Candle::new_unchecked(f64::midpoint(high, low), high, low, close, 1_000.0, 0)
+    }
+
+    #[test]
+    fn rejects_invalid_params() {
+        assert!(matches!(
+            AtrRatchet::new(0, 4.0, 0.1),
+            Err(Error::PeriodZero)
+        ));
+        assert!(matches!(
+            AtrRatchet::new(14, 0.0, 0.1),
+            Err(Error::NonPositiveMultiplier)
+        ));
+        assert!(matches!(
+            AtrRatchet::new(14, 4.0, 0.0),
+            Err(Error::NonPositiveMultiplier)
+        ));
+        assert!(matches!(
+            AtrRatchet::new(14, 4.0, f64::NAN),
+            Err(Error::NonPositiveMultiplier)
+        ));
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let r = AtrRatchet::new(14, 4.0, 0.1).unwrap();
+        assert_eq!(r.params(), (14, 4.0, 0.1));
+        assert_eq!(r.warmup_period(), 14);
+        assert_eq!(r.name(), "AtrRatchet");
+        assert!(!r.is_ready());
+        assert_eq!(r.value(), None);
+    }
+
+    #[test]
+    fn first_emission_at_warmup_period() {
+        let mut r = AtrRatchet::new(5, 4.0, 0.1).unwrap();
+        let candles: Vec<Candle> = (0..12)
+            .map(|i| {
+                let base = 100.0 + f64::from(i);
+                c(base + 1.0, base - 1.0, base)
+            })
+            .collect();
+        let out = r.batch(&candles);
+        for v in out.iter().take(4) {
+            assert!(v.is_none());
+        }
+        assert!(out[4].is_some());
+    }
+
+    #[test]
+    fn uptrend_keeps_stop_below_price() {
+        let mut r = AtrRatchet::new(5, 4.0, 0.05).unwrap();
+        let candles: Vec<Candle> = (0..60)
+            .map(|i| {
+                let base = 100.0 + 2.0 * f64::from(i);
+                c(base + 1.0, base - 1.0, base + 0.5)
+            })
+            .collect();
+        for (o, candle) in r.batch(&candles).into_iter().zip(candles.iter()) {
+            if let Some(o) = o {
+                assert_eq!(o.direction, 1.0);
+                assert!(o.value < candle.close);
+            }
+        }
+    }
+
+    #[test]
+    fn stall_eventually_triggers_flip() {
+        // A long trend then a long flat stretch: the ratchet creeps up each bar
+        // and eventually overtakes the flat close, flipping to short.
+        let mut r = AtrRatchet::new(5, 2.0, 0.5).unwrap();
+        let mut candles: Vec<Candle> = (0..20)
+            .map(|i| {
+                let base = 100.0 + f64::from(i);
+                c(base + 1.0, base - 1.0, base + 0.5)
+            })
+            .collect();
+        // Flat stretch at the last price.
+        candles.extend((0..40).map(|_| c(120.6, 118.6, 119.5)));
+        let dirs: Vec<f64> = r
+            .batch(&candles)
+            .into_iter()
+            .flatten()
+            .map(|o| o.direction)
+            .collect();
+        assert!(
+            dirs.iter().any(|&d| d < 0.0),
+            "the ratchet should eventually flip short"
+        );
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut r = AtrRatchet::new(5, 4.0, 0.1).unwrap();
+        let candles: Vec<Candle> = (0..40)
+            .map(|i| {
+                let base = 100.0 + f64::from(i);
+                c(base + 1.0, base - 1.0, base + 0.5)
+            })
+            .collect();
+        r.batch(&candles);
+        assert!(r.is_ready());
+        r.reset();
+        assert!(!r.is_ready());
+        assert_eq!(r.value(), None);
+        assert_eq!(r.update(candles[0]), None);
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let candles: Vec<Candle> = (0..120)
+            .map(|i| {
+                let base = 100.0 + (f64::from(i) * 0.25).sin() * 9.0;
+                c(base + 2.0, base - 1.5, base + 0.5)
+            })
+            .collect();
+        let batch = AtrRatchet::new(14, 4.0, 0.1).unwrap().batch(&candles);
+        let mut b = AtrRatchet::new(14, 4.0, 0.1).unwrap();
+        let streamed: Vec<_> = candles.iter().map(|c| b.update(*c)).collect();
+        assert_eq!(batch, streamed);
+    }
+}
@@ -0,0 +1,340 @@
+//! Ehlers Autocorrelation Periodogram — estimates the dominant market cycle.
+#![allow(clippy::doc_markdown)]
+
+use std::collections::VecDeque;
+use std::f64::consts::TAU;
+
+use crate::error::{Error, Result};
+use crate::indicators::roofing_filter::RoofingFilter;
+use crate::traits::Indicator;
+
+/// Number of bars averaged into each lagged correlation (Ehlers' `AvgLength`).
+const AVG_LENGTH: usize = 3;
+
+/// Ehlers' **Autocorrelation Periodogram** — measures the **dominant cycle
+/// period** of the market by correlating a roofing-filtered price with lagged
+/// copies of itself and reading off the spectral peak.
+///
+/// From John Ehlers' *Cycle Analytics for Traders* (2013, ch. 8):
+///
+/// ```text
+/// Filt = RoofingFilter(price)                                   (detrend + denoise)
+/// Corr[lag] = Pearson( Filt[0..AvgLength], Filt[lag..lag+AvgLength] )   for lag = 0..max_period
+/// for each candidate period:
+///   power[period] = (Σ Corr[N]·cos(2πN/period))² + (Σ Corr[N]·sin(2πN/period))²
+/// R[period]    = 0.2·power[period] + 0.8·R[period]_{t−1}        (EMA across time)
+/// normalise by a decaying max, then
+/// DominantCycle = centre-of-gravity of periods whose normalised power ≥ 0.5
+/// ```
+///
+/// The autocorrelation function emphasises whatever cycle is actually present and
+/// suppresses noise; transforming it into a periodogram and taking the
+/// power-weighted centre of gravity gives a smooth, robust estimate of the
+/// dominant cycle length. That cycle is the key input for every *adaptive*
+/// indicator (adaptive RSI/CCI/stochastic) — set their lookback from it. The
+/// output is a period in bars within `[min_period, max_period]`.
+///
+/// The first value lands after `max_period + AvgLength` inputs. Each `update` is
+/// O(`max_period²`).
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Indicator, AutocorrelationPeriodogram};
+/// use std::f64::consts::TAU;
+///
+/// let mut indicator = AutocorrelationPeriodogram::new(10, 48).unwrap();
+/// let mut last = None;
+/// for i in 0..200 {
+///     last = indicator.update(100.0 + (TAU * f64::from(i) / 20.0).sin() * 5.0);
+/// }
+/// assert!(last.is_some());
+/// ```
+#[derive(Debug, Clone)]
+pub struct AutocorrelationPeriodogram {
+    min_period: usize,
+    max_period: usize,
+    roof: RoofingFilter,
+    buffer: VecDeque<f64>,
+    r: Vec<f64>,
+    max_pwr: f64,
+    last: Option<f64>,
+}
+
+impl AutocorrelationPeriodogram {
+    /// Construct an autocorrelation periodogram searching cycles in
+    /// `[min_period, max_period]`.
+    ///
+    /// # Errors
+    ///
+    /// Returns [`Error::PeriodZero`] if either period is `0`, or
+    /// [`Error::InvalidPeriod`] if `min_period < AvgLength + 1` or
+    /// `max_period <= min_period`.
+    pub fn new(min_period: usize, max_period: usize) -> Result<Self> {
+        if min_period == 0 || max_period == 0 {
+            return Err(Error::PeriodZero);
+        }
+        if min_period < AVG_LENGTH + 1 || max_period <= min_period {
+            return Err(Error::InvalidPeriod {
+                message: "autocorrelation periodogram needs AvgLength < min_period < max_period",
+            });
+        }
+        Ok(Self {
+            min_period,
+            max_period,
+            roof: RoofingFilter::new(10, max_period)?,
+            buffer: VecDeque::with_capacity(max_period + AVG_LENGTH),
+            r: vec![0.0; max_period + 1],
+            max_pwr: 0.0,
+            last: None,
+        })
+    }
+
+    /// Configured `(min_period, max_period)`.
+    pub const fn periods(&self) -> (usize, usize) {
+        (self.min_period, self.max_period)
+    }
+
+    /// Current dominant-cycle estimate if available.
+    pub const fn value(&self) -> Option<f64> {
+        self.last
+    }
+
+    /// Pearson correlation of the `AvgLength`-deep slices offset by `lag`.
+    /// `buffer` is newest-last; `filt(k)` is the value `k` bars back.
+    fn correlation(&self, lag: usize) -> f64 {
+        let len = self.buffer.len();
+        let filt = |k: usize| self.buffer[len - 1 - k];
+        let m = AVG_LENGTH as f64;
+        let (mut sx, mut sy, mut sxx, mut syy, mut sxy) = (0.0, 0.0, 0.0, 0.0, 0.0);
+        for count in 0..AVG_LENGTH {
+            let x = filt(count);
+            let y = filt(lag + count);
+            sx += x;
+            sy += y;
+            sxx += x * x;
+            syy += y * y;
+            sxy += x * y;
+        }
+        let denom = (m * sxx - sx * sx) * (m * syy - sy * sy);
+        if denom > 0.0 {
+            (m * sxy - sx * sy) / denom.sqrt()
+        } else {
+            0.0
+        }
+    }
+}
+
+impl Indicator for AutocorrelationPeriodogram {
+    type Input = f64;
+    type Output = f64;
+
+    fn update(&mut self, price: f64) -> Option<f64> {
+        if !price.is_finite() {
+            return self.last;
+        }
+        let filt = self.roof.update(price)?;
+        if self.buffer.len() == self.max_period + AVG_LENGTH {
+            self.buffer.pop_front();
+        }
+        self.buffer.push_back(filt);
+        if self.buffer.len() < self.max_period + AVG_LENGTH {
+            return None;
+        }
+
+        // Autocorrelation across lags.
+        let mut corr = vec![0.0; self.max_period + 1];
+        for (lag, c) in corr.iter_mut().enumerate() {
+            *c = self.correlation(lag);
+        }
+
+        // Periodogram: spectral power for each candidate period, EMA'd over time.
+        self.max_pwr *= 0.995;
+        for period in self.min_period..=self.max_period {
+            let mut cosine = 0.0;
+            let mut sine = 0.0;
+            for (n, &cn) in corr
+                .iter()
+                .enumerate()
+                .take(self.max_period + 1)
+                .skip(AVG_LENGTH)
+            {
+                let angle = TAU * n as f64 / period as f64;
+                cosine += cn * angle.cos();
+                sine += cn * angle.sin();
+            }
+            let power = cosine * cosine + sine * sine;
+            self.r[period] = 0.2 * power + 0.8 * self.r[period];
+            if self.r[period] > self.max_pwr {
+                self.max_pwr = self.r[period];
+            }
+        }
+
+        // Power-weighted centre of gravity of the strong periods.
+        let mut spx = 0.0;
+        let mut sp = 0.0;
+        for period in self.min_period..=self.max_period {
+            let pwr = if self.max_pwr > 0.0 {
+                self.r[period] / self.max_pwr
+            } else {
+                0.0
+            };
+            if pwr >= 0.5 {
+                spx += period as f64 * pwr;
+                sp += pwr;
+            }
+        }
+        let dominant = if sp > 0.0 {
+            (spx / sp).clamp(self.min_period as f64, self.max_period as f64)
+        } else {
+            self.min_period as f64
+        };
+        self.last = Some(dominant);
+        Some(dominant)
+    }
+
+    fn reset(&mut self) {
+        self.roof.reset();
+        self.buffer.clear();
+        self.r.iter_mut().for_each(|x| *x = 0.0);
+        self.max_pwr = 0.0;
+        self.last = None;
+    }
+
+    fn warmup_period(&self) -> usize {
+        self.max_period + AVG_LENGTH
+    }
+
+    fn is_ready(&self) -> bool {
+        self.last.is_some()
+    }
+
+    fn name(&self) -> &'static str {
+        "AutocorrelationPeriodogram"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+
+    #[test]
+    fn rejects_invalid_periods() {
+        assert!(matches!(
+            AutocorrelationPeriodogram::new(0, 48),
+            Err(Error::PeriodZero)
+        ));
+        assert!(matches!(
+            AutocorrelationPeriodogram::new(3, 48),
+            Err(Error::InvalidPeriod { .. })
+        ));
+        assert!(matches!(
+            AutocorrelationPeriodogram::new(48, 10),
+            Err(Error::InvalidPeriod { .. })
+        ));
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let p = AutocorrelationPeriodogram::new(10, 48).unwrap();
+        assert_eq!(p.periods(), (10, 48));
+        assert_eq!(p.warmup_period(), 51);
+        assert_eq!(p.name(), "AutocorrelationPeriodogram");
+        assert!(!p.is_ready());
+        assert_eq!(p.value(), None);
+    }
+
+    #[test]
+    fn first_emission_at_warmup_period() {
+        let mut p = AutocorrelationPeriodogram::new(8, 20).unwrap();
+        let xs: Vec<f64> = (0..40)
+            .map(|i| 100.0 + (TAU * f64::from(i) / 12.0).sin() * 5.0)
+            .collect();
+        let out = p.batch(&xs);
+        let warmup = p.warmup_period(); // 23
+        assert_eq!(warmup, 23);
+        for v in out.iter().take(warmup - 1) {
+            assert!(v.is_none());
+        }
+        assert!(out[warmup - 1].is_some());
+    }
+
+    #[test]
+    fn output_within_period_band() {
+        let mut p = AutocorrelationPeriodogram::new(10, 48).unwrap();
+        let xs: Vec<f64> = (0..400)
+            .map(|i| 100.0 + (TAU * f64::from(i) / 20.0).sin() * 5.0)
+            .collect();
+        for v in p.batch(&xs).into_iter().flatten() {
+            assert!((10.0..=48.0).contains(&v), "cycle out of band: {v}");
+        }
+    }
+
+    #[test]
+    fn detects_injected_cycle() {
+        // A clean 20-bar sine: the dominant cycle estimate should settle near 20.
+        let mut p = AutocorrelationPeriodogram::new(10, 48).unwrap();
+        let xs: Vec<f64> = (0..600)
+            .map(|i| 100.0 + (TAU * f64::from(i) / 20.0).sin() * 5.0)
+            .collect();
+        let last = p.batch(&xs).into_iter().flatten().last().unwrap();
+        assert!(
+            (last - 20.0).abs() < 6.0,
+            "expected ~20-bar cycle, got {last}"
+        );
+    }
+
+    #[test]
+    fn ignores_non_finite() {
+        let mut p = AutocorrelationPeriodogram::new(10, 48).unwrap();
+        p.batch(
+            &(0..80)
+                .map(|i| 100.0 + (TAU * f64::from(i) / 20.0).sin() * 5.0)
+                .collect::<Vec<_>>(),
+        );
+        let before = p.value();
+        assert_eq!(p.update(f64::NAN), before);
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut p = AutocorrelationPeriodogram::new(10, 48).unwrap();
+        p.batch(
+            &(0..120)
+                .map(|i| 100.0 + (TAU * f64::from(i) / 20.0).sin() * 5.0)
+                .collect::<Vec<_>>(),
+        );
+        assert!(p.is_ready());
+        p.reset();
+        assert!(!p.is_ready());
+        assert_eq!(p.value(), None);
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let xs: Vec<f64> = (0..200)
+            .map(|i| 100.0 + (TAU * f64::from(i) / 20.0).sin() * 5.0)
+            .collect();
+        let batch = AutocorrelationPeriodogram::new(10, 48).unwrap().batch(&xs);
+        let mut b = AutocorrelationPeriodogram::new(10, 48).unwrap();
+        let streamed: Vec<_> = xs.iter().map(|x| b.update(*x)).collect();
+        assert_eq!(batch, streamed);
+    }
+
+    #[test]
+    fn flat_input_falls_back_to_min_period() {
+        // Constant input has zero variance, so every lag correlation is
+        // degenerate (denom <= 0), the max power is zero and no period clears
+        // the 0.5 threshold -> the dominant cycle defaults to `min_period`.
+        let flat = [100.0_f64; 200];
+        let last = AutocorrelationPeriodogram::new(10, 48)
+            .unwrap()
+            .batch(&flat)
+            .into_iter()
+            .flatten()
+            .last()
+            .unwrap();
+        assert_eq!(last, 10.0);
+    }
+}
@@ -0,0 +1,243 @@
+//! Ehlers Bandpass Filter — isolates the cyclic component around a target period.
+#![allow(clippy::doc_markdown)]
+
+use std::f64::consts::PI;
+
+use crate::error::{Error, Result};
+use crate::traits::Indicator;
+
+/// Ehlers' Bandpass Filter — a two-pole resonator that passes the cyclic content
+/// around a target `period` and rejects both the trend (low frequencies) and the
+/// noise (high frequencies).
+///
+/// From John Ehlers' *Cycle Analytics for Traders* (2013):
+///
+/// ```text
+/// beta  = cos(2π / period)
+/// gamma = 1 / cos(4π · bandwidth / period)
+/// alpha = gamma − sqrt(gamma² − 1)
+/// BP_t  = 0.5·(1 − alpha)·(price_t − price_{t−2})
+///         + beta·(1 + alpha)·BP_{t−1} − alpha·BP_{t−2}
+/// ```
+///
+/// `bandwidth` (a fraction, typically `0.3`) sets how wide a band of periods is
+/// admitted: narrow bandwidth gives a sharp, ringing resonator tuned tightly to
+/// `period`; wide bandwidth lets more of the spectrum through. The output is a
+/// zero-mean oscillator — it swings symmetrically around `0`, peaking when the
+/// dominant cycle aligns with `period`. It is the building block for cycle-phase
+/// and cycle-amplitude work.
+///
+/// The recursion needs two prior prices and two prior outputs; until then it emits
+/// `0` (Ehlers' initial condition), so `warmup_period` is `1` and a value is
+/// produced every bar. Each `update` is O(1).
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Indicator, BandpassFilter};
+///
+/// let mut indicator = BandpassFilter::new(20, 0.3).unwrap();
+/// let mut last = None;
+/// for i in 0..80 {
+///     last = indicator.update(100.0 + (f64::from(i) * 0.3).sin() * 5.0);
+/// }
+/// assert!(last.is_some());
+/// ```
+#[derive(Debug, Clone)]
+pub struct BandpassFilter {
+    period: usize,
+    bandwidth: f64,
+    beta: f64,
+    alpha: f64,
+    prev_price_1: Option<f64>,
+    prev_price_2: Option<f64>,
+    bp1: f64,
+    bp2: f64,
+    last: Option<f64>,
+}
+
+impl BandpassFilter {
+    /// Construct a bandpass filter tuned to `period` with the given `bandwidth`
+    /// fraction.
+    ///
+    /// # Errors
+    ///
+    /// Returns [`Error::PeriodZero`] if `period == 0` and
+    /// [`Error::InvalidParameter`] if `bandwidth` is not finite or outside
+    /// `(0, 1)`.
+    pub fn new(period: usize, bandwidth: f64) -> Result<Self> {
+        if period == 0 {
+            return Err(Error::PeriodZero);
+        }
+        if !bandwidth.is_finite() || bandwidth <= 0.0 || bandwidth >= 1.0 {
+            return Err(Error::InvalidParameter {
+                message: "bandpass bandwidth must be in (0, 1)",
+            });
+        }
+        let period_f = period as f64;
+        let beta = (2.0 * PI / period_f).cos();
+        let gamma = 1.0 / (4.0 * PI * bandwidth / period_f).cos();
+        let alpha = gamma - (gamma * gamma - 1.0).sqrt();
+        Ok(Self {
+            period,
+            bandwidth,
+            beta,
+            alpha,
+            prev_price_1: None,
+            prev_price_2: None,
+            bp1: 0.0,
+            bp2: 0.0,
+            last: None,
+        })
+    }
+
+    /// Configured `(period, bandwidth)`.
+    pub const fn params(&self) -> (usize, f64) {
+        (self.period, self.bandwidth)
+    }
+
+    /// Current value if available.
+    pub const fn value(&self) -> Option<f64> {
+        self.last
+    }
+}
+
+impl Indicator for BandpassFilter {
+    type Input = f64;
+    type Output = f64;
+
+    fn update(&mut self, price: f64) -> Option<f64> {
+        if !price.is_finite() {
+            return self.last;
+        }
+        let bp = match self.prev_price_2 {
+            Some(p2) => {
+                0.5 * (1.0 - self.alpha) * (price - p2) + self.beta * (1.0 + self.alpha) * self.bp1
+                    - self.alpha * self.bp2
+            }
+            None => 0.0,
+        };
+        self.prev_price_2 = self.prev_price_1;
+        self.prev_price_1 = Some(price);
+        self.bp2 = self.bp1;
+        self.bp1 = bp;
+        self.last = Some(bp);
+        Some(bp)
+    }
+
+    fn reset(&mut self) {
+        self.prev_price_1 = None;
+        self.prev_price_2 = None;
+        self.bp1 = 0.0;
+        self.bp2 = 0.0;
+        self.last = None;
+    }
+
+    fn warmup_period(&self) -> usize {
+        1
+    }
+
+    fn is_ready(&self) -> bool {
+        self.last.is_some()
+    }
+
+    fn name(&self) -> &'static str {
+        "BandpassFilter"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    #[test]
+    fn rejects_invalid_params() {
+        assert!(matches!(
+            BandpassFilter::new(0, 0.3),
+            Err(Error::PeriodZero)
+        ));
+        assert!(matches!(
+            BandpassFilter::new(20, 0.0),
+            Err(Error::InvalidParameter { .. })
+        ));
+        assert!(matches!(
+            BandpassFilter::new(20, 1.0),
+            Err(Error::InvalidParameter { .. })
+        ));
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let bp = BandpassFilter::new(20, 0.3).unwrap();
+        assert_eq!(bp.params(), (20, 0.3));
+        assert_eq!(bp.warmup_period(), 1);
+        assert_eq!(bp.name(), "BandpassFilter");
+        assert!(!bp.is_ready());
+        assert_eq!(bp.value(), None);
+    }
+
+    #[test]
+    fn first_bars_are_zero() {
+        let mut bp = BandpassFilter::new(20, 0.3).unwrap();
+        assert_eq!(bp.update(100.0), Some(0.0));
+        assert_eq!(bp.update(101.0), Some(0.0));
+        // From the third bar the recursion is active.
+        assert!(bp.is_ready());
+    }
+
+    #[test]
+    fn constant_input_stays_zero() {
+        // A trend-free flat input has no cyclic content -> output stays 0.
+        let mut bp = BandpassFilter::new(20, 0.3).unwrap();
+        for v in bp.batch(&[50.0; 200]).into_iter().flatten() {
+            assert_relative_eq!(v, 0.0, epsilon = 1e-9);
+        }
+    }
+
+    #[test]
+    fn cyclic_input_oscillates_around_zero() {
+        let mut bp = BandpassFilter::new(20, 0.3).unwrap();
+        let xs: Vec<f64> = (0..400)
+            .map(|i| 100.0 + (2.0 * PI * f64::from(i) / 20.0).sin() * 5.0)
+            .collect();
+        let out: Vec<f64> = bp.batch(&xs).into_iter().flatten().skip(100).collect();
+        let mean = out.iter().sum::<f64>() / out.len() as f64;
+        assert!(
+            mean.abs() < 1.0,
+            "bandpass output should be ~zero mean, got {mean}"
+        );
+        assert!(out.iter().any(|&v| v > 0.5));
+        assert!(out.iter().any(|&v| v < -0.5));
+    }
+
+    #[test]
+    fn ignores_non_finite() {
+        let mut bp = BandpassFilter::new(20, 0.3).unwrap();
+        bp.batch(&(0..40).map(f64::from).collect::<Vec<_>>());
+        let before = bp.value();
+        assert_eq!(bp.update(f64::NAN), before);
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut bp = BandpassFilter::new(20, 0.3).unwrap();
+        bp.batch(&(0..40).map(f64::from).collect::<Vec<_>>());
+        assert!(bp.is_ready());
+        bp.reset();
+        assert!(!bp.is_ready());
+        assert_eq!(bp.update(100.0), Some(0.0));
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let xs: Vec<f64> = (0..120)
+            .map(|i| 100.0 + (f64::from(i) * 0.25).sin() * 9.0)
+            .collect();
+        let batch = BandpassFilter::new(20, 0.3).unwrap().batch(&xs);
+        let mut b = BandpassFilter::new(20, 0.3).unwrap();
+        let streamed: Vec<_> = xs.iter().map(|x| b.update(*x)).collect();
+        assert_eq!(batch, streamed);
+    }
+}
@@ -0,0 +1,254 @@
+//! Better Volume (VSA) — a streaming effort-versus-result oscillator.
+
+use std::collections::VecDeque;
+
+use crate::error::{Error, Result};
+use crate::ohlcv::Candle;
+use crate::traits::Indicator;
+
+/// Better Volume — a Volume-Spread-Analysis (VSA) "effort versus result"
+/// oscillator: how much volume (effort) a bar spent relative to the price range
+/// (result) it achieved, both normalised against their own recent averages.
+///
+/// ```text
+/// range_t   = high_t − low_t
+/// rel_vol   = volume_t / SMA(volume, period)
+/// rel_range = range_t  / SMA(range,  period)
+/// BetterVol = rel_vol − rel_range
+/// ```
+///
+/// Volume-Spread Analysis (Wyckoff, popularised by Tom Williams) reads markets
+/// through the relationship between **effort** (volume) and **result** (the bar's
+/// spread). A bar with heavy volume but a narrow range — `rel_vol` high while
+/// `rel_range` low, so the oscillator is **positive** — is *churn*: large effort
+/// produced little movement, the hallmark of absorption (supply meeting demand at
+/// a top, or vice versa at a bottom). A bar that travels far on light volume —
+/// negative oscillator — shows *ease of movement*, a trend meeting no resistance.
+///
+/// Both legs are normalised by their `period` simple moving averages (including
+/// the current bar), so the output is centred near `0` and self-scales to the
+/// instrument. A degenerate average of `0` makes its leg `0` rather than dividing
+/// by zero. The first value lands after `period` inputs. Each `update` is O(1).
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Candle, Indicator, BetterVolume};
+///
+/// let mut indicator = BetterVolume::new(20).unwrap();
+/// let mut last = None;
+/// for i in 0..60 {
+///     let base = 100.0 + f64::from(i);
+///     let c = Candle::new(base, base + 2.0, base - 2.0, base + 0.5, 1_000.0, 0).unwrap();
+///     last = indicator.update(c);
+/// }
+/// assert!(last.is_some());
+/// ```
+#[derive(Debug, Clone)]
+pub struct BetterVolume {
+    period: usize,
+    volumes: VecDeque<f64>,
+    ranges: VecDeque<f64>,
+    vol_sum: f64,
+    range_sum: f64,
+    last: Option<f64>,
+}
+
+impl BetterVolume {
+    /// Construct a new Better Volume oscillator with the given averaging `period`.
+    ///
+    /// # Errors
+    ///
+    /// Returns [`Error::PeriodZero`] if `period == 0`.
+    pub fn new(period: usize) -> Result<Self> {
+        if period == 0 {
+            return Err(Error::PeriodZero);
+        }
+        Ok(Self {
+            period,
+            volumes: VecDeque::with_capacity(period),
+            ranges: VecDeque::with_capacity(period),
+            vol_sum: 0.0,
+            range_sum: 0.0,
+            last: None,
+        })
+    }
+
+    /// Configured averaging period.
+    pub const fn period(&self) -> usize {
+        self.period
+    }
+
+    /// Current value if available.
+    pub const fn value(&self) -> Option<f64> {
+        self.last
+    }
+}
+
+impl Indicator for BetterVolume {
+    type Input = Candle;
+    type Output = f64;
+
+    fn update(&mut self, candle: Candle) -> Option<f64> {
+        let range = candle.high - candle.low;
+        if self.volumes.len() == self.period {
+            self.vol_sum -= self.volumes.pop_front().expect("non-empty");
+            self.range_sum -= self.ranges.pop_front().expect("non-empty");
+        }
+        self.volumes.push_back(candle.volume);
+        self.ranges.push_back(range);
+        self.vol_sum += candle.volume;
+        self.range_sum += range;
+        if self.volumes.len() < self.period {
+            return None;
+        }
+        let n = self.period as f64;
+        let sma_vol = self.vol_sum / n;
+        let sma_range = self.range_sum / n;
+        let rel_vol = if sma_vol > 0.0 {
+            candle.volume / sma_vol
+        } else {
+            0.0
+        };
+        let rel_range = if sma_range > 0.0 {
+            range / sma_range
+        } else {
+            0.0
+        };
+        let out = rel_vol - rel_range;
+        self.last = Some(out);
+        Some(out)
+    }
+
+    fn reset(&mut self) {
+        self.volumes.clear();
+        self.ranges.clear();
+        self.vol_sum = 0.0;
+        self.range_sum = 0.0;
+        self.last = None;
+    }
+
+    fn warmup_period(&self) -> usize {
+        self.period
+    }
+
+    fn is_ready(&self) -> bool {
+        self.last.is_some()
+    }
+
+    fn name(&self) -> &'static str {
+        "BetterVolume"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    fn candle(high: f64, low: f64, volume: f64) -> Candle {
+        Candle::new_unchecked(low, high, low, high, volume, 0)
+    }
+
+    #[test]
+    fn rejects_zero_period() {
+        assert!(matches!(BetterVolume::new(0), Err(Error::PeriodZero)));
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let bv = BetterVolume::new(20).unwrap();
+        assert_eq!(bv.period(), 20);
+        assert_eq!(bv.warmup_period(), 20);
+        assert_eq!(bv.name(), "BetterVolume");
+        assert!(!bv.is_ready());
+        assert_eq!(bv.value(), None);
+    }
+
+    #[test]
+    fn first_emission_at_warmup_period() {
+        let mut bv = BetterVolume::new(3).unwrap();
+        let candles: Vec<Candle> = (0..6).map(|_| candle(102.0, 100.0, 1_000.0)).collect();
+        let out = bv.batch(&candles);
+        for v in out.iter().take(2) {
+            assert!(v.is_none());
+        }
+        assert!(out[2].is_some());
+    }
+
+    #[test]
+    fn steady_bars_are_neutral() {
+        // Identical volume and range every bar -> rel_vol = rel_range = 1 -> 0.
+        let mut bv = BetterVolume::new(4).unwrap();
+        let candles: Vec<Candle> = (0..10).map(|_| candle(102.0, 100.0, 1_000.0)).collect();
+        let last = bv.batch(&candles).into_iter().flatten().last().unwrap();
+        assert_relative_eq!(last, 0.0, epsilon = 1e-9);
+    }
+
+    #[test]
+    fn churn_bar_is_positive() {
+        // Three normal bars, then a high-volume narrow-range bar -> positive.
+        let mut bv = BetterVolume::new(4).unwrap();
+        let mut candles: Vec<Candle> = (0..3).map(|_| candle(105.0, 100.0, 1_000.0)).collect();
+        candles.push(candle(100.5, 100.0, 5_000.0)); // huge volume, tiny range
+        let last = bv.batch(&candles).into_iter().flatten().last().unwrap();
+        assert!(last > 0.0, "churn bar should be positive, got {last}");
+    }
+
+    #[test]
+    fn ease_of_movement_bar_is_negative() {
+        // Three normal bars, then a wide-range light-volume bar -> negative.
+        let mut bv = BetterVolume::new(4).unwrap();
+        let mut candles: Vec<Candle> = (0..3).map(|_| candle(101.0, 100.0, 5_000.0)).collect();
+        candles.push(candle(115.0, 100.0, 500.0)); // wide range, tiny volume
+        let last = bv.batch(&candles).into_iter().flatten().last().unwrap();
+        assert!(
+            last < 0.0,
+            "ease-of-movement bar should be negative, got {last}"
+        );
+    }
+
+    #[test]
+    fn zero_everything_is_zero() {
+        // Zero volume and zero range -> both legs guarded to 0.
+        let mut bv = BetterVolume::new(3).unwrap();
+        let candles: Vec<Candle> = (0..6).map(|_| candle(100.0, 100.0, 0.0)).collect();
+        for v in bv.batch(&candles).into_iter().flatten() {
+            assert_relative_eq!(v, 0.0, epsilon = 1e-12);
+        }
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut bv = BetterVolume::new(3).unwrap();
+        bv.batch(
+            &(0..6)
+                .map(|_| candle(102.0, 100.0, 1_000.0))
+                .collect::<Vec<_>>(),
+        );
+        assert!(bv.is_ready());
+        bv.reset();
+        assert!(!bv.is_ready());
+        assert_eq!(bv.value(), None);
+        assert_eq!(bv.update(candle(102.0, 100.0, 1_000.0)), None);
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let candles: Vec<Candle> = (0..120)
+            .map(|i| {
+                let base = 100.0 + (f64::from(i) * 0.25).sin() * 9.0;
+                candle(
+                    base + 2.0,
+                    base - 1.5,
+                    1_000.0 + (f64::from(i) * 0.5).cos() * 400.0,
+                )
+            })
+            .collect();
+        let batch = BetterVolume::new(20).unwrap().batch(&candles);
+        let mut b = BetterVolume::new(20).unwrap();
+        let streamed: Vec<_> = candles.iter().map(|c| b.update(*c)).collect();
+        assert_eq!(batch, streamed);
+    }
+}
@@ -0,0 +1,281 @@
+//! Realized Bipower Variation — a jump-robust quadratic-variation estimator.
+
+use std::collections::VecDeque;
+
+use crate::error::{Error, Result};
+use crate::traits::Indicator;
+
+/// Realized Bipower Variation — the sum of *adjacent* absolute log-return
+/// products over the trailing `period` returns, scaled to estimate integrated
+/// variance.
+///
+/// ```text
+/// r_t = ln(price_t / price_{t−1})
+/// BV  = (π / 2) · Σ |r_t| · |r_{t−1}|   over the window
+/// ```
+///
+/// Bipower variation (Barndorff-Nielsen & Shephard 2004) estimates the same
+/// integrated variance as [`RealizedVolatility`](crate::RealizedVolatility)'s
+/// `Σ r²`, but by multiplying *neighbouring* absolute returns rather than
+/// squaring a single one. A price jump inflates exactly one return; because that
+/// return appears in a product with its (ordinary) neighbour rather than squared,
+/// its contribution stays bounded — so `BV` is **robust to jumps** while realized
+/// variance is not. The constant `π / 2 = μ₁⁻²` (with `μ₁ = E|Z| = √(2/π)` for a
+/// standard normal) debiases the product of two half-normal magnitudes back to a
+/// variance scale.
+///
+/// The output is on the **variance** scale (the jump-robust counterpart of
+/// realized *variance*, not volatility); take its square root for a volatility,
+/// and compare `RV − BV` to isolate the jump contribution. A window of `period`
+/// returns contributes `period − 1` adjacent products; each `update` is O(1) via
+/// a running sum.
+///
+/// Non-finite and non-positive prices are ignored (the log return would be
+/// undefined): the tick is dropped, state is left untouched, and the last value
+/// is returned.
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{BipowerVariation, Indicator};
+///
+/// let mut indicator = BipowerVariation::new(20).unwrap();
+/// let mut last = None;
+/// for i in 0..80 {
+///     last = indicator.update(100.0 + (f64::from(i) * 0.3).sin() * 5.0);
+/// }
+/// assert!(last.is_some());
+/// ```
+#[derive(Debug, Clone)]
+pub struct BipowerVariation {
+    period: usize,
+    prev_price: Option<f64>,
+    /// Rolling window of the last `period` log returns.
+    window: VecDeque<f64>,
+    /// Running sum of adjacent absolute-return products inside the window.
+    sum_adjacent: f64,
+    last: Option<f64>,
+}
+
+impl BipowerVariation {
+    /// Construct a new bipower-variation indicator.
+    ///
+    /// `period` is the number of log returns in the rolling window; the estimate
+    /// uses the `period − 1` adjacent products between them.
+    ///
+    /// # Errors
+    /// Returns [`Error::PeriodZero`] if `period == 0`, or
+    /// [`Error::InvalidPeriod`] if `period == 1` (an adjacent product needs at
+    /// least two returns).
+    pub fn new(period: usize) -> Result<Self> {
+        if period == 0 {
+            return Err(Error::PeriodZero);
+        }
+        if period < 2 {
+            return Err(Error::InvalidPeriod {
+                message: "bipower variation period must be >= 2",
+            });
+        }
+        Ok(Self {
+            period,
+            prev_price: None,
+            window: VecDeque::with_capacity(period),
+            sum_adjacent: 0.0,
+            last: None,
+        })
+    }
+
+    /// Configured period.
+    pub const fn period(&self) -> usize {
+        self.period
+    }
+}
+
+/// `μ₁⁻² = π / 2`, the debiasing constant for a product of half-normal returns.
+const MU1_INV_SQ: f64 = std::f64::consts::FRAC_PI_2;
+
+impl Indicator for BipowerVariation {
+    type Input = f64;
+    type Output = f64;
+
+    fn update(&mut self, input: f64) -> Option<f64> {
+        // Non-finite / non-positive prices are skipped: `ln(input / prev)` is
+        // undefined, so the tick must not enter the return window.
+        if !input.is_finite() || input <= 0.0 {
+            return self.last;
+        }
+        let Some(prev) = self.prev_price else {
+            self.prev_price = Some(input);
+            return None;
+        };
+        self.prev_price = Some(input);
+        // `prev` came from `self.prev_price`, gated by the guard above, so it is
+        // finite and positive — the log return is always well-defined.
+        let r = (input / prev).ln();
+        // The incoming return forms a product with the current last return.
+        if let Some(&back) = self.window.back() {
+            self.sum_adjacent += back.abs() * r.abs();
+        }
+        self.window.push_back(r);
+        if self.window.len() > self.period {
+            let first = self.window.pop_front().expect("window is non-empty");
+            // The product between the dropped return and the new front leaves.
+            let second = *self.window.front().expect("window still has >= 1 element");
+            self.sum_adjacent -= first.abs() * second.abs();
+        }
+        if self.window.len() < self.period {
+            return None;
+        }
+        // Products are non-negative; the rolling subtraction can leave a tiny
+        // negative residual when returns are ~0, so clamp before scaling.
+        let bv = MU1_INV_SQ * self.sum_adjacent.max(0.0);
+        self.last = Some(bv);
+        Some(bv)
+    }
+
+    fn reset(&mut self) {
+        self.prev_price = None;
+        self.window.clear();
+        self.sum_adjacent = 0.0;
+        self.last = None;
+    }
+
+    fn warmup_period(&self) -> usize {
+        // The first log return needs a previous price, then the window fills.
+        self.period + 1
+    }
+
+    fn is_ready(&self) -> bool {
+        self.last.is_some()
+    }
+
+    fn name(&self) -> &'static str {
+        "BipowerVariation"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    #[test]
+    fn rejects_zero_period() {
+        assert!(matches!(BipowerVariation::new(0), Err(Error::PeriodZero)));
+    }
+
+    #[test]
+    fn rejects_period_one() {
+        assert!(matches!(
+            BipowerVariation::new(1),
+            Err(Error::InvalidPeriod { .. })
+        ));
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let bv = BipowerVariation::new(20).unwrap();
+        assert_eq!(bv.period(), 20);
+        assert_eq!(bv.warmup_period(), 21);
+        assert_eq!(bv.name(), "BipowerVariation");
+        assert!(!bv.is_ready());
+    }
+
+    #[test]
+    fn first_emission_at_warmup_period() {
+        let mut bv = BipowerVariation::new(5).unwrap();
+        let out = bv.batch(&(1..=20).map(f64::from).collect::<Vec<_>>());
+        for v in out.iter().take(5) {
+            assert!(v.is_none());
+        }
+        assert!(out[5].is_some());
+    }
+
+    #[test]
+    fn known_value() {
+        // period = 2: one adjacent product. r1 = ln(1.1), r2 = ln(0.9).
+        // BV = (π/2)·|r1|·|r2|.
+        let mut bv = BipowerVariation::new(2).unwrap();
+        let out = bv.batch(&[100.0, 110.0, 99.0]);
+        assert!(out[1].is_none());
+        let r1 = (110.0_f64 / 100.0).ln();
+        let r2 = (99.0_f64 / 110.0).ln();
+        let expected = std::f64::consts::FRAC_PI_2 * r1.abs() * r2.abs();
+        assert_relative_eq!(out[2].unwrap(), expected, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn rolling_window_drops_oldest_product() {
+        // period = 2, four prices -> two emissions, each a single product.
+        let mut bv = BipowerVariation::new(2).unwrap();
+        let out = bv.batch(&[100.0, 110.0, 99.0, 105.0]);
+        let r2 = (99.0_f64 / 110.0).ln();
+        let r3 = (105.0_f64 / 99.0).ln();
+        let expected = std::f64::consts::FRAC_PI_2 * r2.abs() * r3.abs();
+        assert_relative_eq!(out[3].unwrap(), expected, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn constant_series_yields_zero() {
+        let mut bv = BipowerVariation::new(10).unwrap();
+        for v in bv.batch(&[100.0; 40]).into_iter().flatten() {
+            assert_relative_eq!(v, 0.0, epsilon = 1e-12);
+        }
+    }
+
+    #[test]
+    fn output_is_non_negative() {
+        let mut bv = BipowerVariation::new(20).unwrap();
+        let prices: Vec<f64> = (1..=200)
+            .map(|i| 100.0 + (f64::from(i) * 0.3).sin() * 12.0)
+            .collect();
+        for v in bv.batch(&prices).into_iter().flatten() {
+            assert!(v >= 0.0, "bipower variation must be non-negative, got {v}");
+        }
+    }
+
+    #[test]
+    fn ignores_non_finite_input() {
+        let mut bv = BipowerVariation::new(5).unwrap();
+        let out = bv.batch(&(1..=20).map(f64::from).collect::<Vec<_>>());
+        let last = *out.last().unwrap();
+        assert!(last.is_some());
+        assert_eq!(bv.update(f64::NAN), last);
+        assert_eq!(bv.update(f64::INFINITY), last);
+    }
+
+    #[test]
+    fn skips_non_positive_prices() {
+        let mut bv = BipowerVariation::new(5).unwrap();
+        let warmup = bv.batch(&(1..=20).map(f64::from).collect::<Vec<_>>());
+        let baseline = warmup.last().copied().flatten().expect("warmed up");
+        assert_eq!(bv.update(-5.0), Some(baseline));
+        assert_eq!(bv.update(0.0), Some(baseline));
+        // State untouched: a clone advanced by the same real tick agrees.
+        let mut control = bv.clone();
+        let after = bv.update(21.0).expect("ready");
+        assert_eq!(control.update(21.0).expect("ready"), after);
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut bv = BipowerVariation::new(5).unwrap();
+        bv.batch(&(1..=20).map(f64::from).collect::<Vec<_>>());
+        assert!(bv.is_ready());
+        bv.reset();
+        assert!(!bv.is_ready());
+        assert_eq!(bv.update(1.0), None);
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let prices: Vec<f64> = (1..=120)
+            .map(|i| 100.0 + (f64::from(i) * 0.25).sin() * 9.0)
+            .collect();
+        let batch = BipowerVariation::new(20).unwrap().batch(&prices);
+        let mut b = BipowerVariation::new(20).unwrap();
+        let streamed: Vec<_> = prices.iter().map(|p| b.update(*p)).collect();
+        assert_eq!(batch, streamed);
+    }
+}
@@ -0,0 +1,193 @@
+//! Body Size Percent — candle body as a fraction of its range.
+
+use crate::ohlcv::Candle;
+use crate::traits::Indicator;
+
+/// Body Size Percent — the absolute body as a fraction of the bar's range.
+///
+/// ```text
+/// BodySizePct = |close − open| / (high − low)
+/// ```
+///
+/// The result lives in `[0, 1]`: `1` is a full-bodied marubozu (the bar opened
+/// at one extreme and closed at the other, no wicks), `0` a doji (open equals
+/// close, the bar is all wick). It is the *unsigned* magnitude companion to
+/// [`BalanceOfPower`](crate::BalanceOfPower) — where `BoP` keeps the direction,
+/// this keeps only the conviction, which is exactly what candlestick body /
+/// range filters key on. A zero-range bar carries no information and yields `0`.
+///
+/// This is a stateless per-bar transform: every candle produces one value.
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Candle, Indicator, BodySizePct};
+///
+/// let mut indicator = BodySizePct::new();
+/// // body |12 - 10| = 2, range 14 - 10 = 4 -> 0.5.
+/// let c = Candle::new(10.0, 14.0, 10.0, 12.0, 10.0, 0).unwrap();
+/// assert!((indicator.update(c).unwrap() - 0.5).abs() < 1e-12);
+/// ```
+#[derive(Debug, Clone, Default)]
+pub struct BodySizePct {
+    has_emitted: bool,
+}
+
+impl BodySizePct {
+    /// Construct a new Body Size Percent transform.
+    pub const fn new() -> Self {
+        Self { has_emitted: false }
+    }
+}
+
+impl Indicator for BodySizePct {
+    type Input = Candle;
+    type Output = f64;
+
+    fn update(&mut self, candle: Candle) -> Option<f64> {
+        self.has_emitted = true;
+        let range = candle.high - candle.low;
+        let out = if range == 0.0 {
+            // A zero-range bar has no body proportion to speak of.
+            0.0
+        } else {
+            (candle.close - candle.open).abs() / range
+        };
+        Some(out)
+    }
+
+    fn reset(&mut self) {
+        self.has_emitted = false;
+    }
+
+    fn warmup_period(&self) -> usize {
+        1
+    }
+
+    fn is_ready(&self) -> bool {
+        self.has_emitted
+    }
+
+    fn name(&self) -> &'static str {
+        "BodySizePct"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    fn candle(open: f64, high: f64, low: f64, close: f64, ts: i64) -> Candle {
+        Candle::new(open, high, low, close, 1.0, ts).unwrap()
+    }
+
+    #[test]
+    fn reference_value() {
+        // |12 - 10| / (14 - 10) = 0.5.
+        let mut bsp = BodySizePct::new();
+        assert_relative_eq!(
+            bsp.update(candle(10.0, 14.0, 10.0, 12.0, 0)).unwrap(),
+            0.5,
+            epsilon = 1e-12
+        );
+    }
+
+    #[test]
+    fn marubozu_is_one() {
+        // open == low, close == high, no wicks -> full body -> 1.
+        let mut bsp = BodySizePct::new();
+        assert_relative_eq!(
+            bsp.update(candle(9.0, 11.0, 9.0, 11.0, 0)).unwrap(),
+            1.0,
+            epsilon = 1e-12
+        );
+    }
+
+    #[test]
+    fn doji_is_zero() {
+        // open == close with a real range -> body 0.
+        let mut bsp = BodySizePct::new();
+        assert_relative_eq!(
+            bsp.update(candle(10.0, 12.0, 8.0, 10.0, 0)).unwrap(),
+            0.0,
+            epsilon = 1e-12
+        );
+    }
+
+    #[test]
+    fn unsigned_regardless_of_direction() {
+        // A red bar with the same body magnitude reads identically to a green one.
+        let mut bsp = BodySizePct::new();
+        let green = bsp.update(candle(10.0, 14.0, 10.0, 12.0, 0)).unwrap();
+        let mut bsp2 = BodySizePct::new();
+        let red = bsp2.update(candle(12.0, 14.0, 10.0, 10.0, 0)).unwrap();
+        assert_relative_eq!(green, red, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn zero_range_bar_yields_zero() {
+        let mut bsp = BodySizePct::new();
+        assert_relative_eq!(
+            bsp.update(candle(10.0, 10.0, 10.0, 10.0, 0)).unwrap(),
+            0.0,
+            epsilon = 1e-12
+        );
+    }
+
+    #[test]
+    fn stays_within_unit_range() {
+        let candles: Vec<Candle> = (0..100)
+            .map(|i| {
+                let mid = 100.0 + (f64::from(i) * 0.2).sin() * 8.0;
+                let close = mid + (f64::from(i) * 0.5).cos() * 2.0;
+                candle(mid, mid + 3.0, mid - 3.0, close, i64::from(i))
+            })
+            .collect();
+        let mut bsp = BodySizePct::new();
+        for v in bsp.batch(&candles).into_iter().flatten() {
+            assert!((0.0..=1.0).contains(&v), "BodySizePct {v} outside [0, 1]");
+        }
+    }
+
+    #[test]
+    fn name_metadata() {
+        let bsp = BodySizePct::new();
+        assert_eq!(bsp.name(), "BodySizePct");
+    }
+
+    #[test]
+    fn emits_from_first_candle() {
+        let mut bsp = BodySizePct::new();
+        assert_eq!(bsp.warmup_period(), 1);
+        assert!(!bsp.is_ready());
+        assert!(bsp.update(candle(10.0, 11.0, 9.0, 10.0, 0)).is_some());
+        assert!(bsp.is_ready());
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut bsp = BodySizePct::new();
+        bsp.update(candle(10.0, 11.0, 9.0, 10.0, 0));
+        assert!(bsp.is_ready());
+        bsp.reset();
+        assert!(!bsp.is_ready());
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let candles: Vec<Candle> = (0..40)
+            .map(|i| {
+                let base = 100.0 + f64::from(i);
+                candle(base, base + 2.0, base - 2.0, base + 1.0, i64::from(i))
+            })
+            .collect();
+        let mut a = BodySizePct::new();
+        let mut b = BodySizePct::new();
+        assert_eq!(
+            a.batch(&candles),
+            candles.iter().map(|x| b.update(*x)).collect::<Vec<_>>()
+        );
+    }
+}
@@ -1,7 +1,5 @@
 //! Bollinger Bands.

-use std::collections::VecDeque;
-
 use crate::error::{Error, Result};
 use crate::traits::Indicator;

@@ -49,7 +47,13 @@ pub struct BollingerOutput {
 pub struct BollingerBands {
    period: usize,
    multiplier: f64,
-    window: VecDeque<f64>,
+    /// Fixed-capacity ring buffer of the last `period` finite inputs. A flat
+    /// `Box<[f64]>` with a manual write cursor beats `VecDeque` on this hot path.
+    buf: Box<[f64]>,
+    /// Index of the next slot to write — also the oldest element once full.
+    head: usize,
+    /// Number of slots filled, saturating at `period`.
+    count: usize,
    sum: f64,
    sum_sq: f64,
    /// Number of finite updates since the running sums were last reseeded
@@ -80,7 +84,9 @@ impl BollingerBands {
        Ok(Self {
            period,
            multiplier,
-            window: VecDeque::with_capacity(period),
+            buf: vec![0.0; period].into_boxed_slice(),
+            head: 0,
+            count: 0,
            sum: 0.0,
            sum_sq: 0.0,
            updates_since_recompute: 0,
@@ -102,8 +108,84 @@ impl BollingerBands {
        self.multiplier
    }

+    /// Vectorized flat batch for bindings: returns `n * 4` values laid out as
+    /// `[upper, middle, lower, stddev]` per input row, warmup rows all `NaN`.
+    ///
+    /// For a fresh, all-finite slice it inlines `update`'s rolling `sum`/`sum_sq`
+    /// and drift-reseed, writing the four band values directly instead of an
+    /// `Option<BollingerOutput>` per element. Same add/subtract order, same reseed
+    /// cadence, same variance/`sqrt` math — so it is *bit-for-bit* equal to
+    /// replaying `update`, including the long-stream drift bound. Any other state,
+    /// or a non-finite element, defers to the exact `update` replay.
+    ///
+    /// This is a *separate* entry point from the trait [`batch`](crate::BatchExt::batch),
+    /// which returns `Vec<Option<BollingerOutput>>`; only the bindings, which want
+    /// a flat `f64` buffer, call this.
+    pub fn batch_bands(&mut self, inputs: &[f64]) -> Vec<f64> {
+        let p = self.period;
+        let n = inputs.len();
+        if self.count != 0
+            || self.updates_since_recompute != 0
+            || !inputs.iter().all(|x| x.is_finite())
+        {
+            // Slow path: exact replay of `update` into the flat layout.
+            let mut out = vec![f64::NAN; n * 4];
+            for (i, &x) in inputs.iter().enumerate() {
+                if let Some(o) = self.update(x) {
+                    out[i * 4] = o.upper;
+                    out[i * 4 + 1] = o.middle;
+                    out[i * 4 + 2] = o.lower;
+                    out[i * 4 + 3] = o.stddev;
+                }
+            }
+            return out;
+        }
+
+        let p_f64 = p as f64;
+        let mult = self.multiplier;
+        // Pre-sized output: warmup rows stay NaN, ready rows are written in place
+        // by index — no per-row `push` length/capacity check.
+        let mut out = vec![f64::NAN; n * 4];
+        for (i, &x) in inputs.iter().enumerate() {
+            if self.count == p {
+                let old = self.buf[self.head];
+                self.sum -= old;
+                self.sum_sq -= old * old;
+                self.buf[self.head] = x;
+                self.sum += x;
+                self.sum_sq += x * x;
+            } else {
+                self.buf[self.head] = x;
+                self.sum += x;
+                self.sum_sq += x * x;
+                self.count += 1;
+            }
+            self.head += 1;
+            if self.head == p {
+                self.head = 0;
+            }
+            self.updates_since_recompute += 1;
+            if self.updates_since_recompute >= RECOMPUTE_EVERY * p {
+                let chronological = self.buf[self.head..].iter().chain(&self.buf[..self.head]);
+                self.sum = chronological.clone().copied().sum();
+                self.sum_sq = chronological.map(|&v| v * v).sum();
+                self.updates_since_recompute = 0;
+            }
+            if self.count == p {
+                let mean = self.sum / p_f64;
+                let stddev = (self.sum_sq / p_f64 - mean * mean).max(0.0).sqrt();
+                let band = mult * stddev;
+                out[i * 4] = mean + band;
+                out[i * 4 + 1] = mean;
+                out[i * 4 + 2] = mean - band;
+                out[i * 4 + 3] = stddev;
+            }
+        }
+        out
+    }
+
    fn current(&self) -> Option<BollingerOutput> {
-        if self.window.len() != self.period {
+        if self.count != self.period {
            return None;
        }
        let n = self.period as f64;
@@ -129,25 +211,38 @@ impl Indicator for BollingerBands {
        if !input.is_finite() {
            return self.current();
        }
-        if self.window.len() == self.period {
-            let old = self.window.pop_front().expect("non-empty");
+        if self.count == self.period {
+            let old = self.buf[self.head];
            self.sum -= old;
            self.sum_sq -= old * old;
+            self.buf[self.head] = input;
+            self.sum += input;
+            self.sum_sq += input * input;
+        } else {
+            self.buf[self.head] = input;
+            self.sum += input;
+            self.sum_sq += input * input;
+            self.count += 1;
+        }
+        self.head += 1;
+        if self.head == self.period {
+            self.head = 0;
        }
-        self.window.push_back(input);
-        self.sum += input;
-        self.sum_sq += input * input;
        self.updates_since_recompute += 1;
        if self.updates_since_recompute >= RECOMPUTE_EVERY * self.period {
-            self.sum = self.window.iter().copied().sum();
-            self.sum_sq = self.window.iter().copied().map(|x| x * x).sum();
+            // Reseed in chronological order (oldest at `head`) to keep the running
+            // sums bit-equivalent to a fresh from-scratch pass on stable inputs.
+            let chronological = self.buf[self.head..].iter().chain(&self.buf[..self.head]);
+            self.sum = chronological.clone().copied().sum();
+            self.sum_sq = chronological.map(|&x| x * x).sum();
            self.updates_since_recompute = 0;
        }
        self.current()
    }

    fn reset(&mut self) {
-        self.window.clear();
+        self.head = 0;
+        self.count = 0;
        self.sum = 0.0;
        self.sum_sq = 0.0;
        self.updates_since_recompute = 0;
@@ -158,7 +253,7 @@ impl Indicator for BollingerBands {
    }

    fn is_ready(&self) -> bool {
-        self.window.len() == self.period
+        self.count == self.period
    }

    fn name(&self) -> &'static str {
@@ -171,6 +266,7 @@ mod tests {
    use super::*;
    use crate::traits::BatchExt;
    use approx::assert_relative_eq;
+    use std::collections::VecDeque;

    fn naive(prices: &[f64], period: usize, mult: f64) -> BollingerOutput {
        assert!(
@@ -332,6 +428,79 @@ mod tests {
        );
    }

+    fn bits_eq(a: &[f64], b: &[f64]) -> bool {
+        a.len() == b.len()
+            && a.iter()
+                .zip(b)
+                .all(|(x, y)| x == y || (x.is_nan() && y.is_nan()))
+    }
+
+    /// Flat `n*4` `[upper, middle, lower, stddev]` replay of `update`.
+    fn bb_replay(period: usize, mult: f64, series: &[f64]) -> Vec<f64> {
+        let mut bb = BollingerBands::new(period, mult).unwrap();
+        let mut out = Vec::with_capacity(series.len() * 4);
+        for &x in series {
+            match bb.update(x) {
+                Some(o) => out.extend_from_slice(&[o.upper, o.middle, o.lower, o.stddev]),
+                None => out.extend_from_slice(&[f64::NAN; 4]),
+            }
+        }
+        out
+    }
+
+    #[test]
+    fn batch_bands_fast_path_is_bit_identical_with_reseed() {
+        // > 16*period inputs so the drift-reseed branch fires inside batch_bands.
+        let series: Vec<f64> = (0..500)
+            .map(|i| (f64::from(i) * 0.2).sin() * 10.0 + 50.0)
+            .collect();
+        let mut bb = BollingerBands::new(20, 2.0).unwrap();
+        let got = bb.batch_bands(&series);
+        assert!(bits_eq(&got, &bb_replay(20, 2.0, &series)));
+        // State continues identically.
+        let mut ref_bb = BollingerBands::new(20, 2.0).unwrap();
+        for &x in &series {
+            ref_bb.update(x);
+        }
+        assert_eq!(bb.update(55.0), ref_bb.update(55.0));
+    }
+
+    #[test]
+    fn batch_bands_falls_back_on_non_finite() {
+        let series = [1.0, 2.0, 3.0, f64::NAN, 5.0, 6.0, 7.0];
+        let mut bb = BollingerBands::new(3, 2.0).unwrap();
+        assert!(bits_eq(
+            &bb.batch_bands(&series),
+            &bb_replay(3, 2.0, &series)
+        ));
+    }
+
+    #[test]
+    fn batch_bands_falls_back_when_not_fresh() {
+        let mut bb = BollingerBands::new(3, 2.0).unwrap();
+        bb.update(99.0);
+        let series = [1.0, 2.0, 3.0, 4.0];
+        let mut ref_bb = BollingerBands::new(3, 2.0).unwrap();
+        ref_bb.update(99.0);
+        let mut want = Vec::new();
+        for &x in &series {
+            match ref_bb.update(x) {
+                Some(o) => want.extend_from_slice(&[o.upper, o.middle, o.lower, o.stddev]),
+                None => want.extend_from_slice(&[f64::NAN; 4]),
+            }
+        }
+        assert!(bits_eq(&bb.batch_bands(&series), &want));
+    }
+
+    #[test]
+    fn batch_bands_sub_period_slice_is_all_nan() {
+        let series = [1.0, 2.0, 3.0];
+        let mut bb = BollingerBands::new(10, 2.0).unwrap();
+        let got = bb.batch_bands(&series);
+        assert!(bits_eq(&got, &bb_replay(10, 2.0, &series)));
+        assert!(got.iter().all(|x| x.is_nan()) && got.len() == 12);
+    }
+
    #[test]
    fn ignores_non_finite_input() {
        let mut bb = BollingerBands::new(5, 2.0).unwrap();
@@ -0,0 +1,256 @@
+//! Bomar Bands — adaptive percentage bands that contain a target fraction of
+//! recent price.
+
+use std::collections::VecDeque;
+
+use crate::error::{Error, Result};
+use crate::indicators::rolling_quantile::quantile_sorted;
+use crate::traits::Indicator;
+
+/// Bomar Bands output.
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub struct BomarBandsOutput {
+    /// Upper band: `middle + |middle| · p`.
+    pub upper: f64,
+    /// Middle line: the simple moving average over the window.
+    pub middle: f64,
+    /// Lower band: `middle − |middle| · p`.
+    pub lower: f64,
+}
+
+/// Bomar Bands: percentage bands whose width adapts so that a fixed `coverage`
+/// fraction of recent closes falls inside them.
+///
+/// The Bomar Bands predate Bollinger Bands; John Bollinger cites them as an
+/// inspiration — percentage bands around a moving average, with the percentage
+/// tuned so a fixed share (classically ~85%) of price stayed within. Wickra
+/// realises that idea deterministically: the half-width is the `coverage`
+/// quantile of the relative deviations from the midline, so by construction
+/// `coverage` of the window's closes lie inside the bands.
+///
+/// ```text
+/// middle = SMA(close, period)
+/// dev_i  = | close_i / middle − 1 |          // relative distance from midline
+/// p      = coverage-quantile of { dev_i }     // type-7 interpolation
+/// upper  = middle + |middle| · p
+/// lower  = middle − |middle| · p
+/// ```
+///
+/// Unlike the fixed-percentage [`MaEnvelope`](crate::MaEnvelope), the offset
+/// here is data-driven: the bands widen in turbulent regimes and tighten in
+/// quiet ones without a volatility input. Unlike Bollinger Bands, the width is
+/// an order statistic of the actual deviations rather than a multiple of the
+/// standard deviation, so it is unaffected by the shape of the tails beyond the
+/// `coverage` rank. When the midline is zero the relative deviation is
+/// undefined and the bands collapse onto the midline.
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{BomarBands, Indicator};
+///
+/// let mut indicator = BomarBands::new(20, 0.85).unwrap();
+/// let mut last = None;
+/// for i in 0..40 {
+///     last = indicator.update(100.0 + f64::from(i % 7));
+/// }
+/// assert!(last.is_some());
+/// ```
+#[derive(Debug, Clone)]
+pub struct BomarBands {
+    period: usize,
+    coverage: f64,
+    window: VecDeque<f64>,
+    scratch: Vec<f64>,
+}
+
+impl BomarBands {
+    /// Construct new Bomar Bands.
+    ///
+    /// `coverage` is the target fraction of closes to contain, in `(0.0, 1.0]`.
+    ///
+    /// # Errors
+    /// Returns [`Error::PeriodZero`] if `period == 0`, or
+    /// [`Error::InvalidParameter`] if `coverage` is not a finite value in
+    /// `(0.0, 1.0]`.
+    pub fn new(period: usize, coverage: f64) -> Result<Self> {
+        if period == 0 {
+            return Err(Error::PeriodZero);
+        }
+        if !coverage.is_finite() || coverage <= 0.0 || coverage > 1.0 {
+            return Err(Error::InvalidParameter {
+                message: "bomar bands coverage must be a finite value in (0.0, 1.0]",
+            });
+        }
+        Ok(Self {
+            period,
+            coverage,
+            window: VecDeque::with_capacity(period),
+            scratch: Vec::with_capacity(period),
+        })
+    }
+
+    /// Configured period.
+    pub const fn period(&self) -> usize {
+        self.period
+    }
+
+    /// Configured coverage fraction.
+    pub const fn coverage(&self) -> f64 {
+        self.coverage
+    }
+}
+
+impl Indicator for BomarBands {
+    type Input = f64;
+    type Output = BomarBandsOutput;
+
+    fn update(&mut self, value: f64) -> Option<BomarBandsOutput> {
+        if self.window.len() == self.period {
+            self.window.pop_front();
+        }
+        self.window.push_back(value);
+        if self.window.len() < self.period {
+            return None;
+        }
+        let sum: f64 = self.window.iter().sum();
+        let middle = sum / (self.period as f64);
+        let denom = middle.abs();
+
+        self.scratch.clear();
+        for &v in &self.window {
+            let dev = if denom == 0.0 {
+                0.0
+            } else {
+                ((v - middle) / denom).abs()
+            };
+            self.scratch.push(dev);
+        }
+        self.scratch.sort_by(f64::total_cmp);
+        let p = quantile_sorted(&self.scratch, self.coverage);
+        let offset = denom * p;
+
+        Some(BomarBandsOutput {
+            upper: middle + offset,
+            middle,
+            lower: middle - offset,
+        })
+    }
+
+    fn reset(&mut self) {
+        self.window.clear();
+        self.scratch.clear();
+    }
+
+    fn warmup_period(&self) -> usize {
+        self.period
+    }
+
+    fn is_ready(&self) -> bool {
+        self.window.len() == self.period
+    }
+
+    fn name(&self) -> &'static str {
+        "BomarBands"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    #[test]
+    fn rejects_zero_period() {
+        assert!(matches!(BomarBands::new(0, 0.85), Err(Error::PeriodZero)));
+        assert!(BomarBands::new(1, 0.85).is_ok());
+    }
+
+    #[test]
+    fn rejects_out_of_range_coverage() {
+        assert!(matches!(
+            BomarBands::new(20, 0.0),
+            Err(Error::InvalidParameter { .. })
+        ));
+        assert!(matches!(
+            BomarBands::new(20, 1.1),
+            Err(Error::InvalidParameter { .. })
+        ));
+        assert!(matches!(
+            BomarBands::new(20, -0.5),
+            Err(Error::InvalidParameter { .. })
+        ));
+        assert!(matches!(
+            BomarBands::new(20, f64::NAN),
+            Err(Error::InvalidParameter { .. })
+        ));
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let bb = BomarBands::new(20, 0.85).unwrap();
+        assert_eq!(bb.period(), 20);
+        assert_relative_eq!(bb.coverage(), 0.85, epsilon = 1e-12);
+        assert_eq!(bb.warmup_period(), 20);
+        assert_eq!(bb.name(), "BomarBands");
+        assert!(!bb.is_ready());
+    }
+
+    #[test]
+    fn warms_up_then_emits() {
+        let mut bb = BomarBands::new(4, 0.85).unwrap();
+        assert!(bb.update(100.0).is_none());
+        assert!(bb.update(102.0).is_none());
+        assert!(bb.update(98.0).is_none());
+        assert!(bb.update(104.0).is_some());
+        assert!(bb.is_ready());
+    }
+
+    #[test]
+    fn known_bands() {
+        // mean=101; |dev| = {1,1,3,3}/101; coverage 0.85 quantile -> 3/101.
+        // offset = 101 * 3/101 = 3 -> upper 104, lower 98.
+        let mut bb = BomarBands::new(4, 0.85).unwrap();
+        let out = bb.batch(&[100.0, 102.0, 98.0, 104.0]);
+        let last = out[3].unwrap();
+        assert_relative_eq!(last.middle, 101.0, epsilon = 1e-9);
+        assert_relative_eq!(last.upper, 104.0, epsilon = 1e-9);
+        assert_relative_eq!(last.lower, 98.0, epsilon = 1e-9);
+    }
+
+    #[test]
+    fn zero_midline_collapses_bands() {
+        // Window mean exactly zero -> relative deviation undefined -> collapse.
+        let mut bb = BomarBands::new(2, 0.85).unwrap();
+        let out = bb.batch(&[3.0, -3.0]);
+        let last = out[1].unwrap();
+        assert_relative_eq!(last.middle, 0.0, epsilon = 1e-12);
+        assert_relative_eq!(last.upper, 0.0, epsilon = 1e-12);
+        assert_relative_eq!(last.lower, 0.0, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn rolling_window_evicts_oldest() {
+        // Eight values through a period-4 window: only the last four survive,
+        // reproducing the `known_bands` window.
+        let mut bb = BomarBands::new(4, 0.85).unwrap();
+        let out = bb.batch(&[50.0, 50.0, 50.0, 50.0, 100.0, 102.0, 98.0, 104.0]);
+        let last = out[7].unwrap();
+        assert_relative_eq!(last.middle, 101.0, epsilon = 1e-9);
+        assert_relative_eq!(last.upper, 104.0, epsilon = 1e-9);
+        assert_relative_eq!(last.lower, 98.0, epsilon = 1e-9);
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut bb = BomarBands::new(4, 0.85).unwrap();
+        for v in [100.0, 102.0, 98.0, 104.0] {
+            bb.update(v);
+        }
+        assert!(bb.is_ready());
+        bb.reset();
+        assert!(!bb.is_ready());
+        assert!(bb.update(100.0).is_none());
+    }
+}
@@ -0,0 +1,171 @@
+//! Central Pivot Range (CPR) — the pivot plus its two central levels.
+
+use crate::ohlcv::Candle;
+use crate::traits::Indicator;
+
+/// Output of [`CentralPivotRange`]: the pivot and the two central lines that
+/// bracket it.
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub struct CentralPivotRangeOutput {
+    /// Pivot point `(high + low + close) / 3`.
+    pub pivot: f64,
+    /// Top central line — the higher of the two central levels.
+    pub tc: f64,
+    /// Bottom central line — the lower of the two central levels.
+    pub bc: f64,
+}
+
+/// Central Pivot Range (CPR) — the classic pivot point flanked by two "central"
+/// levels whose separation gauges the day's expected character.
+///
+/// ```text
+/// pivot = (high + low + close) / 3
+/// bc'   = (high + low) / 2
+/// tc'   = 2·pivot − bc'
+/// TC    = max(tc', bc'),   BC = min(tc', bc')
+/// ```
+///
+/// The CPR is computed from the **previous** period's bar (feed it completed
+/// daily/weekly bars). The width of the range `TC − BC` is the headline read: a
+/// **narrow** CPR signals a likely trending day (price has little balance area to
+/// chew through), while a **wide** CPR signals a likely range-bound, balanced
+/// day. Price opening above the whole range is bullish, below it bearish, inside
+/// it neutral. The `tc'`/`bc'` formulas are symmetric about the pivot; this
+/// implementation labels the larger as `TC` and the smaller as `BC` so `TC >= BC`
+/// always holds.
+///
+/// There are no parameters and no warmup — each completed bar yields one CPR.
+/// Each `update` is O(1).
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Candle, Indicator, CentralPivotRange};
+///
+/// let mut indicator = CentralPivotRange::new();
+/// let prev_day = Candle::new(101.0, 110.0, 90.0, 105.0, 1_000.0, 0).unwrap();
+/// let cpr = indicator.update(prev_day).unwrap();
+/// assert!(cpr.tc >= cpr.bc);
+/// ```
+#[derive(Debug, Clone, Default)]
+pub struct CentralPivotRange {
+    ready: bool,
+}
+
+impl CentralPivotRange {
+    /// Construct a new Central Pivot Range. The indicator is parameter-free.
+    #[must_use]
+    pub const fn new() -> Self {
+        Self { ready: false }
+    }
+}
+
+impl Indicator for CentralPivotRange {
+    type Input = Candle;
+    type Output = CentralPivotRangeOutput;
+
+    fn update(&mut self, candle: Candle) -> Option<CentralPivotRangeOutput> {
+        let pivot = (candle.high + candle.low + candle.close) / 3.0;
+        let bc_raw = f64::midpoint(candle.high, candle.low);
+        let tc_raw = 2.0 * pivot - bc_raw;
+        let tc = tc_raw.max(bc_raw);
+        let bc = tc_raw.min(bc_raw);
+        self.ready = true;
+        Some(CentralPivotRangeOutput { pivot, tc, bc })
+    }
+
+    fn reset(&mut self) {
+        self.ready = false;
+    }
+
+    fn warmup_period(&self) -> usize {
+        1
+    }
+
+    fn is_ready(&self) -> bool {
+        self.ready
+    }
+
+    fn name(&self) -> &'static str {
+        "CentralPivotRange"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+
+    fn c(high: f64, low: f64, close: f64) -> Candle {
+        Candle::new_unchecked(close, high, low, close, 1_000.0, 0)
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let cpr = CentralPivotRange::new();
+        assert_eq!(cpr.warmup_period(), 1);
+        assert_eq!(cpr.name(), "CentralPivotRange");
+        assert!(!cpr.is_ready());
+    }
+
+    #[test]
+    fn formula_reference_values() {
+        // H=110, L=90, C=105 -> pivot = 305/3; bc' = 100; tc' = 2*pivot - 100.
+        let out = CentralPivotRange::new()
+            .update(c(110.0, 90.0, 105.0))
+            .unwrap();
+        let pivot = 305.0 / 3.0;
+        let bc_raw = 100.0;
+        let tc_raw = 2.0 * pivot - bc_raw;
+        assert!((out.pivot - pivot).abs() < 1e-12);
+        assert!((out.tc - tc_raw.max(bc_raw)).abs() < 1e-12);
+        assert!((out.bc - tc_raw.min(bc_raw)).abs() < 1e-12);
+    }
+
+    #[test]
+    fn tc_never_below_bc() {
+        let out = CentralPivotRange::new()
+            .update(c(200.0, 100.0, 150.0))
+            .unwrap();
+        assert!(out.tc >= out.bc);
+    }
+
+    #[test]
+    fn constant_bar_collapses_range() {
+        // H = L = C -> pivot = bc' = tc' = the price; range collapses.
+        let out = CentralPivotRange::new()
+            .update(c(50.0, 50.0, 50.0))
+            .unwrap();
+        assert_eq!(out.pivot, 50.0);
+        assert_eq!(out.tc, 50.0);
+        assert_eq!(out.bc, 50.0);
+    }
+
+    #[test]
+    fn ready_after_first_update() {
+        let mut cpr = CentralPivotRange::new();
+        assert!(!cpr.is_ready());
+        cpr.update(c(11.0, 9.0, 10.0));
+        assert!(cpr.is_ready());
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut cpr = CentralPivotRange::new();
+        cpr.update(c(11.0, 9.0, 10.0));
+        assert!(cpr.is_ready());
+        cpr.reset();
+        assert!(!cpr.is_ready());
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let candles: Vec<Candle> = (0..40)
+            .map(|i| c(f64::from(i) + 2.0, f64::from(i), f64::from(i) + 1.0))
+            .collect();
+        let batch = CentralPivotRange::new().batch(&candles);
+        let mut b = CentralPivotRange::new();
+        let streamed: Vec<_> = candles.iter().map(|x| b.update(*x)).collect();
+        assert_eq!(batch, streamed);
+    }
+}
@@ -0,0 +1,157 @@
+//! Close vs Open — the signed relative body of a bar.
+
+use crate::ohlcv::Candle;
+use crate::traits::Indicator;
+
+/// Close vs Open — the bar's body as a signed fraction of its open price.
+///
+/// ```text
+/// CloseVsOpen = (close − open) / open
+/// ```
+///
+/// A scale-free, signed measure of how far price travelled from open to close:
+/// `+0.02` is a bar that closed 2% above its open (a green bar), `−0.02` the
+/// mirror. Unlike [`BalanceOfPower`](crate::BalanceOfPower) — which normalises
+/// the body by the bar *range* — this normalises by the *open price*, so it is
+/// directly comparable to a return and stays meaningful across instruments of
+/// different nominal price. A zero open carries no scale and yields `0`.
+///
+/// This is a stateless per-bar transform: every candle produces one value.
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Candle, Indicator, CloseVsOpen};
+///
+/// let mut indicator = CloseVsOpen::new();
+/// // open 100, close 102 -> +0.02.
+/// let c = Candle::new(100.0, 103.0, 99.0, 102.0, 10.0, 0).unwrap();
+/// assert!((indicator.update(c).unwrap() - 0.02).abs() < 1e-12);
+/// ```
+#[derive(Debug, Clone, Default)]
+pub struct CloseVsOpen {
+    has_emitted: bool,
+}
+
+impl CloseVsOpen {
+    /// Construct a new Close vs Open transform.
+    pub const fn new() -> Self {
+        Self { has_emitted: false }
+    }
+}
+
+impl Indicator for CloseVsOpen {
+    type Input = Candle;
+    type Output = f64;
+
+    fn update(&mut self, candle: Candle) -> Option<f64> {
+        self.has_emitted = true;
+        let out = if candle.open == 0.0 {
+            // A zero open price carries no scale to normalise against.
+            0.0
+        } else {
+            (candle.close - candle.open) / candle.open
+        };
+        Some(out)
+    }
+
+    fn reset(&mut self) {
+        self.has_emitted = false;
+    }
+
+    fn warmup_period(&self) -> usize {
+        1
+    }
+
+    fn is_ready(&self) -> bool {
+        self.has_emitted
+    }
+
+    fn name(&self) -> &'static str {
+        "CloseVsOpen"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    fn candle(open: f64, high: f64, low: f64, close: f64, ts: i64) -> Candle {
+        Candle::new(open, high, low, close, 1.0, ts).unwrap()
+    }
+
+    #[test]
+    fn reference_value() {
+        // (102 - 100) / 100 = 0.02.
+        let mut cvo = CloseVsOpen::new();
+        assert_relative_eq!(
+            cvo.update(candle(100.0, 103.0, 99.0, 102.0, 0)).unwrap(),
+            0.02,
+            epsilon = 1e-12
+        );
+    }
+
+    #[test]
+    fn negative_body_is_negative() {
+        let mut cvo = CloseVsOpen::new();
+        // close below open -> negative.
+        assert_relative_eq!(
+            cvo.update(candle(100.0, 101.0, 97.0, 98.0, 0)).unwrap(),
+            -0.02,
+            epsilon = 1e-12
+        );
+    }
+
+    #[test]
+    fn zero_open_yields_zero() {
+        // Candle permits a zero open (only finiteness + OHLC ordering checked).
+        let mut cvo = CloseVsOpen::new();
+        assert_relative_eq!(
+            cvo.update(candle(0.0, 1.0, 0.0, 0.5, 0)).unwrap(),
+            0.0,
+            epsilon = 1e-12
+        );
+    }
+
+    #[test]
+    fn name_metadata() {
+        let cvo = CloseVsOpen::new();
+        assert_eq!(cvo.name(), "CloseVsOpen");
+    }
+
+    #[test]
+    fn emits_from_first_candle() {
+        let mut cvo = CloseVsOpen::new();
+        assert_eq!(cvo.warmup_period(), 1);
+        assert!(!cvo.is_ready());
+        assert!(cvo.update(candle(10.0, 11.0, 9.0, 10.0, 0)).is_some());
+        assert!(cvo.is_ready());
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut cvo = CloseVsOpen::new();
+        cvo.update(candle(10.0, 11.0, 9.0, 10.0, 0));
+        assert!(cvo.is_ready());
+        cvo.reset();
+        assert!(!cvo.is_ready());
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let candles: Vec<Candle> = (0..40)
+            .map(|i| {
+                let base = 100.0 + f64::from(i);
+                candle(base, base + 2.0, base - 2.0, base + 1.0, i64::from(i))
+            })
+            .collect();
+        let mut a = CloseVsOpen::new();
+        let mut b = CloseVsOpen::new();
+        assert_eq!(
+            a.batch(&candles),
+            candles.iter().map(|x| b.update(*x)).collect::<Vec<_>>()
+        );
+    }
+}
@@ -0,0 +1,258 @@
+//! Ehlers Correlation Trend Indicator (CTI) — Pearson correlation of price vs. time.
+#![allow(clippy::doc_markdown)]
+
+use std::collections::VecDeque;
+
+use crate::error::{Error, Result};
+use crate::traits::Indicator;
+
+/// Ehlers' **Correlation Trend Indicator** (CTI) — the Pearson correlation
+/// coefficient between price and a perfectly straight ramp over the lookback.
+///
+/// ```text
+/// CTI = corr( price over the window , [0, 1, …, period−1] )
+/// ```
+///
+/// John Ehlers' CTI asks "how closely does recent price track a straight line?"
+/// by correlating the windowed price against the time index itself. A reading near
+/// `+1` means price is rising in a near-perfect line (strong uptrend); near `−1`
+/// means a clean downtrend; near `0` means no linear trend (a range or choppy
+/// market). Because correlation is scale- and offset-invariant, the slope's
+/// steepness does not matter — only how *linear* the move is — which makes CTI an
+/// unusually clean trend/range classifier. It differs from
+/// [`Autocorrelation`](crate::Autocorrelation), which correlates price with a
+/// *lagged copy of itself* rather than with time.
+///
+/// The output is in `[−1, +1]`; a flat window (zero price variance) returns `0`.
+/// The first value lands after `period` inputs; each `update` recomputes the
+/// correlation over the window in O(`period`).
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Indicator, CorrelationTrendIndicator};
+///
+/// let mut indicator = CorrelationTrendIndicator::new(20).unwrap();
+/// let mut last = None;
+/// for i in 0..40 {
+///     last = indicator.update(100.0 + f64::from(i)); // a clean uptrend
+/// }
+/// assert!((last.unwrap() - 1.0).abs() < 1e-9);
+/// ```
+#[derive(Debug, Clone)]
+pub struct CorrelationTrendIndicator {
+    period: usize,
+    window: VecDeque<f64>,
+    last: Option<f64>,
+}
+
+impl CorrelationTrendIndicator {
+    /// Construct a CTI over `period` bars.
+    ///
+    /// # Errors
+    ///
+    /// Returns [`Error::InvalidPeriod`] if `period < 2` (a correlation needs two
+    /// points).
+    pub fn new(period: usize) -> Result<Self> {
+        if period < 2 {
+            return Err(Error::InvalidPeriod {
+                message: "CTI needs period >= 2",
+            });
+        }
+        Ok(Self {
+            period,
+            window: VecDeque::with_capacity(period),
+            last: None,
+        })
+    }
+
+    /// Configured lookback period.
+    pub const fn period(&self) -> usize {
+        self.period
+    }
+
+    /// Current value if available.
+    pub const fn value(&self) -> Option<f64> {
+        self.last
+    }
+
+    fn compute(&self) -> f64 {
+        let n = self.period as f64;
+        let mut sum_x = 0.0;
+        let mut sum_xx = 0.0;
+        let mut sum_xt = 0.0;
+        for (i, &x) in self.window.iter().enumerate() {
+            let t = i as f64;
+            sum_x += x;
+            sum_xx += x * x;
+            sum_xt += x * t;
+        }
+        // Time index 0..n-1 has closed-form sums.
+        let sum_t = n * (n - 1.0) / 2.0;
+        let sum_tt = (n - 1.0) * n * (2.0 * n - 1.0) / 6.0;
+        let cov = n * sum_xt - sum_x * sum_t;
+        let var_x = n * sum_xx - sum_x * sum_x;
+        let var_t = n * sum_tt - sum_t * sum_t;
+        let denom = (var_x * var_t).sqrt();
+        if denom == 0.0 {
+            0.0
+        } else {
+            (cov / denom).clamp(-1.0, 1.0)
+        }
+    }
+}
+
+impl Indicator for CorrelationTrendIndicator {
+    type Input = f64;
+    type Output = f64;
+
+    fn update(&mut self, input: f64) -> Option<f64> {
+        if !input.is_finite() {
+            return self.last;
+        }
+        if self.window.len() == self.period {
+            self.window.pop_front();
+        }
+        self.window.push_back(input);
+        if self.window.len() < self.period {
+            return None;
+        }
+        let out = self.compute();
+        self.last = Some(out);
+        Some(out)
+    }
+
+    fn reset(&mut self) {
+        self.window.clear();
+        self.last = None;
+    }
+
+    fn warmup_period(&self) -> usize {
+        self.period
+    }
+
+    fn is_ready(&self) -> bool {
+        self.last.is_some()
+    }
+
+    fn name(&self) -> &'static str {
+        "CorrelationTrendIndicator"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    #[test]
+    fn rejects_period_below_two() {
+        assert!(matches!(
+            CorrelationTrendIndicator::new(1),
+            Err(Error::InvalidPeriod { .. })
+        ));
+        assert!(CorrelationTrendIndicator::new(2).is_ok());
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let cti = CorrelationTrendIndicator::new(20).unwrap();
+        assert_eq!(cti.period(), 20);
+        assert_eq!(cti.warmup_period(), 20);
+        assert_eq!(cti.name(), "CorrelationTrendIndicator");
+        assert!(!cti.is_ready());
+        assert_eq!(cti.value(), None);
+    }
+
+    #[test]
+    fn first_emission_at_warmup_period() {
+        let mut cti = CorrelationTrendIndicator::new(4).unwrap();
+        let out = cti.batch(&[1.0, 2.0, 3.0, 4.0, 5.0]);
+        for v in out.iter().take(3) {
+            assert!(v.is_none());
+        }
+        assert!(out[3].is_some());
+    }
+
+    #[test]
+    fn clean_uptrend_is_one() {
+        let mut cti = CorrelationTrendIndicator::new(10).unwrap();
+        let last = cti
+            .batch(&(0..40).map(f64::from).collect::<Vec<_>>())
+            .into_iter()
+            .flatten()
+            .last()
+            .unwrap();
+        assert_relative_eq!(last, 1.0, epsilon = 1e-9);
+    }
+
+    #[test]
+    fn clean_downtrend_is_minus_one() {
+        let mut cti = CorrelationTrendIndicator::new(10).unwrap();
+        let last = cti
+            .batch(&(0..40).map(|i| 100.0 - f64::from(i)).collect::<Vec<_>>())
+            .into_iter()
+            .flatten()
+            .last()
+            .unwrap();
+        assert_relative_eq!(last, -1.0, epsilon = 1e-9);
+    }
+
+    #[test]
+    fn flat_window_is_zero() {
+        let mut cti = CorrelationTrendIndicator::new(8).unwrap();
+        let last = cti.batch(&[7.0; 16]).into_iter().flatten().last().unwrap();
+        assert_relative_eq!(last, 0.0, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn output_in_range() {
+        let mut cti = CorrelationTrendIndicator::new(20).unwrap();
+        for v in cti
+            .batch(
+                &(0..200)
+                    .map(|i| 100.0 + (f64::from(i) * 0.3).sin() * 10.0)
+                    .collect::<Vec<_>>(),
+            )
+            .into_iter()
+            .flatten()
+        {
+            assert!((-1.0..=1.0).contains(&v));
+        }
+    }
+
+    #[test]
+    fn ignores_non_finite() {
+        let mut cti = CorrelationTrendIndicator::new(4).unwrap();
+        let ready = cti
+            .batch(&[1.0, 2.0, 3.0, 4.0])
+            .into_iter()
+            .flatten()
+            .last()
+            .unwrap();
+        assert_eq!(cti.update(f64::NAN), Some(ready));
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut cti = CorrelationTrendIndicator::new(4).unwrap();
+        cti.batch(&[1.0, 2.0, 3.0, 4.0]);
+        assert!(cti.is_ready());
+        cti.reset();
+        assert!(!cti.is_ready());
+        assert_eq!(cti.value(), None);
+        assert_eq!(cti.update(1.0), None);
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let xs: Vec<f64> = (0..120)
+            .map(|i| 100.0 + (f64::from(i) * 0.25).sin() * 9.0)
+            .collect();
+        let batch = CorrelationTrendIndicator::new(20).unwrap().batch(&xs);
+        let mut b = CorrelationTrendIndicator::new(20).unwrap();
+        let streamed: Vec<_> = xs.iter().map(|x| b.update(*x)).collect();
+        assert_eq!(batch, streamed);
+    }
+}
@@ -0,0 +1,218 @@
+//! Derivative Oscillator (Constance Brown).
+
+use crate::error::{Error, Result};
+use crate::indicators::ema::Ema;
+use crate::indicators::rsi::Rsi;
+use crate::indicators::sma::Sma;
+use crate::traits::Indicator;
+
+/// Derivative Oscillator — Constance Brown's double-smoothed RSI histogram.
+///
+/// The RSI is smoothed twice with EMAs, then a simple moving average of that
+/// double-smoothed line is subtracted as a signal, leaving a zero-centered
+/// histogram:
+///
+/// ```text
+/// rsi   = RSI(price, rsi_period)
+/// s1    = EMA(rsi, smooth1)
+/// s2    = EMA(s1,  smooth2)          // double-smoothed RSI
+/// signal = SMA(s2, signal_period)
+/// DerivativeOscillator = s2 - signal
+/// ```
+///
+/// The double EMA smoothing strips the RSI's high-frequency noise, and
+/// subtracting the SMA signal removes the residual level, so the result
+/// oscillates around zero: positive (and rising) bars mark accelerating bullish
+/// momentum, negative bars bearish. Brown's defaults are `rsi_period = 14`,
+/// `smooth1 = 5`, `smooth2 = 3`, `signal_period = 9`.
+///
+/// The first value lands after `rsi_period + smooth1 + smooth2 + signal_period − 2`
+/// inputs, the point at which the whole RSI → EMA → EMA → SMA chain is seeded.
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{DerivativeOscillator, Indicator};
+///
+/// let mut indicator = DerivativeOscillator::new(14, 5, 3, 9).unwrap();
+/// let mut last = None;
+/// for i in 0..120 {
+///     last = indicator.update(100.0 + (f64::from(i) * 0.2).sin() * 5.0);
+/// }
+/// assert!(last.is_some());
+/// ```
+#[derive(Debug, Clone)]
+pub struct DerivativeOscillator {
+    rsi: Rsi,
+    ema1: Ema,
+    ema2: Ema,
+    signal: Sma,
+    warmup: usize,
+}
+
+impl DerivativeOscillator {
+    /// Construct a Derivative Oscillator with the RSI, two EMA smoothing, and
+    /// SMA signal periods.
+    ///
+    /// # Errors
+    ///
+    /// Returns [`Error::PeriodZero`] if any period is `0`.
+    pub fn new(
+        rsi_period: usize,
+        smooth1: usize,
+        smooth2: usize,
+        signal_period: usize,
+    ) -> Result<Self> {
+        if rsi_period == 0 || smooth1 == 0 || smooth2 == 0 || signal_period == 0 {
+            return Err(Error::PeriodZero);
+        }
+        Ok(Self {
+            rsi: Rsi::new(rsi_period)?,
+            ema1: Ema::new(smooth1)?,
+            ema2: Ema::new(smooth2)?,
+            signal: Sma::new(signal_period)?,
+            // RSI seeds at rsi_period + 1, then each stage adds (len - 1).
+            warmup: rsi_period + smooth1 + smooth2 + signal_period - 2,
+        })
+    }
+
+    /// Total warmup length (also returned by `warmup_period`).
+    pub const fn warmup(&self) -> usize {
+        self.warmup
+    }
+}
+
+impl Indicator for DerivativeOscillator {
+    type Input = f64;
+    type Output = f64;
+
+    fn update(&mut self, input: f64) -> Option<f64> {
+        let rsi = self.rsi.update(input)?;
+        let s1 = self.ema1.update(rsi)?;
+        let s2 = self.ema2.update(s1)?;
+        let signal = self.signal.update(s2)?;
+        Some(s2 - signal)
+    }
+
+    fn reset(&mut self) {
+        self.rsi.reset();
+        self.ema1.reset();
+        self.ema2.reset();
+        self.signal.reset();
+    }
+
+    fn warmup_period(&self) -> usize {
+        self.warmup
+    }
+
+    fn is_ready(&self) -> bool {
+        self.signal.is_ready()
+    }
+
+    fn name(&self) -> &'static str {
+        "DerivativeOscillator"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    #[test]
+    fn rejects_zero_periods() {
+        assert!(matches!(
+            DerivativeOscillator::new(0, 5, 3, 9),
+            Err(Error::PeriodZero)
+        ));
+        assert!(matches!(
+            DerivativeOscillator::new(14, 0, 3, 9),
+            Err(Error::PeriodZero)
+        ));
+        assert!(matches!(
+            DerivativeOscillator::new(14, 5, 0, 9),
+            Err(Error::PeriodZero)
+        ));
+        assert!(matches!(
+            DerivativeOscillator::new(14, 5, 3, 0),
+            Err(Error::PeriodZero)
+        ));
+    }
+
+    /// Cover the const accessor `warmup` and the Indicator-impl `warmup_period`
+    /// + `name`.
+    #[test]
+    fn accessors_and_metadata() {
+        let d = DerivativeOscillator::new(14, 5, 3, 9).unwrap();
+        // 14 + 5 + 3 + 9 - 2 = 29.
+        assert_eq!(d.warmup(), 29);
+        assert_eq!(d.warmup_period(), 29);
+        assert_eq!(d.name(), "DerivativeOscillator");
+    }
+
+    #[test]
+    fn first_emission_matches_warmup_period() {
+        let prices: Vec<f64> = (0..60)
+            .map(|i| 100.0 + (f64::from(i) * 0.3).sin() * 6.0)
+            .collect();
+        let mut d = DerivativeOscillator::new(14, 5, 3, 9).unwrap();
+        let out = d.batch(&prices);
+        let warmup = d.warmup_period();
+        for (i, v) in out.iter().enumerate().take(warmup - 1) {
+            assert!(v.is_none(), "index {i} must be None during warmup");
+        }
+        assert!(
+            out[warmup - 1].is_some(),
+            "first value must land at warmup_period - 1"
+        );
+    }
+
+    #[test]
+    fn matches_manual_chain() {
+        // Equals RSI -> EMA -> EMA, minus the SMA signal of that line.
+        let prices: Vec<f64> = (0..80)
+            .map(|i| 100.0 + (f64::from(i) * 0.4).sin() * 8.0)
+            .collect();
+        let mut d = DerivativeOscillator::new(14, 5, 3, 9).unwrap();
+        let mut rsi = Rsi::new(14).unwrap();
+        let mut e1 = Ema::new(5).unwrap();
+        let mut e2 = Ema::new(3).unwrap();
+        let mut sig = Sma::new(9).unwrap();
+        for (i, &p) in prices.iter().enumerate() {
+            let got = d.update(p);
+            let want = rsi
+                .update(p)
+                .and_then(|r| e1.update(r))
+                .and_then(|x| e2.update(x))
+                .and_then(|s2| sig.update(s2).map(|s| s2 - s));
+            assert_eq!(got.is_some(), want.is_some(), "readiness mismatch at {i}");
+            if let (Some(a), Some(b)) = (got, want) {
+                assert_relative_eq!(a, b, epsilon = 1e-9);
+            }
+        }
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut d = DerivativeOscillator::new(14, 5, 3, 9).unwrap();
+        d.batch(&(0..60).map(|i| 100.0 + f64::from(i)).collect::<Vec<_>>());
+        assert!(d.is_ready());
+        d.reset();
+        assert!(!d.is_ready());
+        assert_eq!(d.update(1.0), None);
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let prices: Vec<f64> = (0..80)
+            .map(|i| 50.0 + (f64::from(i) * 0.5).sin() * 10.0)
+            .collect();
+        let mut a = DerivativeOscillator::new(14, 5, 3, 9).unwrap();
+        let mut b = DerivativeOscillator::new(14, 5, 3, 9).unwrap();
+        assert_eq!(
+            a.batch(&prices),
+            prices.iter().map(|p| b.update(*p)).collect::<Vec<_>>()
+        );
+    }
+}
@@ -0,0 +1,169 @@
+//! Disparity Index.
+
+use crate::error::Result;
+use crate::indicators::sma::Sma;
+use crate::traits::Indicator;
+
+/// Disparity Index — the percentage gap between price and its moving average.
+///
+/// ```text
+/// Disparity = 100 * (price - SMA(price, period)) / SMA(price, period)
+/// ```
+///
+/// Originating in Japanese technical analysis (*kairi*), the disparity index
+/// expresses how far price has stretched from its `period`-bar simple moving
+/// average, as a percentage of that average. Positive readings mean price is
+/// above the mean (potentially overbought / strong), negative readings mean it
+/// is below (potentially oversold / weak); the magnitude measures how
+/// over-extended the move is.
+///
+/// The first output lands once the inner SMA is ready (input `period`). If the
+/// moving average is exactly zero the gap percentage is undefined and the index
+/// returns `0.0`.
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{DisparityIndex, Indicator};
+///
+/// let mut indicator = DisparityIndex::new(14).unwrap();
+/// let mut last = None;
+/// for i in 0..80 {
+///     last = indicator.update(100.0 + f64::from(i));
+/// }
+/// assert!(last.is_some());
+/// ```
+#[derive(Debug, Clone)]
+pub struct DisparityIndex {
+    period: usize,
+    sma: Sma,
+}
+
+impl DisparityIndex {
+    /// Construct a disparity index over `period` inputs.
+    ///
+    /// # Errors
+    ///
+    /// Returns [`crate::Error::PeriodZero`] if `period == 0`.
+    pub fn new(period: usize) -> Result<Self> {
+        Ok(Self {
+            period,
+            sma: Sma::new(period)?,
+        })
+    }
+
+    /// Configured period.
+    pub const fn period(&self) -> usize {
+        self.period
+    }
+}
+
+impl Indicator for DisparityIndex {
+    type Input = f64;
+    type Output = f64;
+
+    fn update(&mut self, input: f64) -> Option<f64> {
+        let mean = self.sma.update(input)?;
+        if mean == 0.0 {
+            return Some(0.0);
+        }
+        Some(100.0 * (input - mean) / mean)
+    }
+
+    fn reset(&mut self) {
+        self.sma.reset();
+    }
+
+    fn warmup_period(&self) -> usize {
+        self.period
+    }
+
+    fn is_ready(&self) -> bool {
+        self.sma.is_ready()
+    }
+
+    fn name(&self) -> &'static str {
+        "DisparityIndex"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    #[test]
+    fn rejects_zero_period() {
+        assert!(DisparityIndex::new(0).is_err());
+    }
+
+    /// Cover the const accessor `period` and the Indicator-impl `warmup_period`
+    /// + `name`.
+    #[test]
+    fn accessors_and_metadata() {
+        let di = DisparityIndex::new(14).unwrap();
+        assert_eq!(di.period(), 14);
+        assert_eq!(di.warmup_period(), 14);
+        assert_eq!(di.name(), "DisparityIndex");
+    }
+
+    #[test]
+    fn warmup_then_known_value() {
+        // SMA(3) of [2, 4, 6] = 4; price 6 -> 100 * (6 - 4) / 4 = 50.
+        let mut di = DisparityIndex::new(3).unwrap();
+        assert_eq!(di.update(2.0), None);
+        assert_eq!(di.update(4.0), None);
+        assert_relative_eq!(di.update(6.0).unwrap(), 50.0, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn constant_series_is_zero() {
+        // Price equals its own mean -> zero disparity.
+        let mut di = DisparityIndex::new(5).unwrap();
+        for v in di.batch(&[42.0; 20]).into_iter().flatten() {
+            assert_relative_eq!(v, 0.0, epsilon = 1e-12);
+        }
+    }
+
+    #[test]
+    fn negative_when_below_mean() {
+        // SMA(3) of [10, 8, 6] = 8; price 6 -> 100 * (6 - 8) / 8 = -25.
+        let mut di = DisparityIndex::new(3).unwrap();
+        let v = di.batch(&[10.0, 8.0, 6.0]);
+        assert_relative_eq!(v[2].unwrap(), -25.0, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn zero_mean_returns_zero() {
+        // A window summing to zero (mean 0) makes the percentage undefined; the
+        // index returns 0.0 rather than a non-finite value.
+        let mut di = DisparityIndex::new(2).unwrap();
+        assert_eq!(di.update(-3.0), None);
+        // SMA(2) of [-3, 3] = 0 -> guarded to 0.0.
+        assert_relative_eq!(di.update(3.0).unwrap(), 0.0, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut di = DisparityIndex::new(5).unwrap();
+        di.batch(&(1..=20).map(f64::from).collect::<Vec<_>>());
+        assert!(di.is_ready());
+        di.reset();
+        assert!(!di.is_ready());
+        assert_eq!(di.update(1.0), None);
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let prices: Vec<f64> = (1..=30)
+            .map(|i| 50.0 + (f64::from(i) * 0.3).sin() * 10.0)
+            .collect();
+        let mut a = DisparityIndex::new(7).unwrap();
+        let mut b = DisparityIndex::new(7).unwrap();
+        assert_eq!(
+            a.batch(&prices),
+            prices.iter().map(|p| b.update(*p)).collect::<Vec<_>>()
+        );
+    }
+}
@@ -0,0 +1,301 @@
+//! Dynamic Momentum Index (Chande's volatility-adaptive RSI).
+
+use std::collections::VecDeque;
+
+use crate::error::{Error, Result};
+use crate::indicators::sma::Sma;
+use crate::indicators::std_dev::StdDev;
+use crate::traits::Indicator;
+
+// Chande's definitional constants.
+const STD_PERIOD: usize = 5; // volatility window
+const STD_AVG_PERIOD: usize = 10; // smoothing of the volatility
+const MIN_PERIOD: usize = 5; // fastest RSI lookback
+const MAX_PERIOD: usize = 30; // slowest RSI lookback
+
+/// Dynamic Momentum Index — Tushar Chande's RSI whose lookback shrinks in
+/// volatile markets and lengthens in calm ones.
+///
+/// A standard RSI uses a fixed period; the DMI varies it from the recent
+/// volatility so the oscillator stays responsive when the market is fast and
+/// smooth when it is quiet:
+///
+/// ```text
+/// vol     = StdDev(close, 5)
+/// vol_avg = SMA(vol, 10)
+/// Vi      = vol / vol_avg                       (volatility index)
+/// td      = clamp(round(period / Vi), 5, 30)    (dynamic lookback)
+/// avg_gain, avg_loss = simple means of the last `td` price changes
+/// DMI     = 100 * avg_gain / (avg_gain + avg_loss)
+/// ```
+///
+/// High volatility (`Vi > 1`) shortens `td` toward `5` (faster); low volatility
+/// lengthens it toward `30` (slower). The averages of gains and losses are
+/// simple means over the last `td` changes (not Wilder-smoothed), recomputed as
+/// the window length flexes. Output is bounded in `[0, 100]`; a flat market
+/// returns the neutral `50`.
+///
+/// The first value lands after `MAX_PERIOD + 1 = 31` inputs, so the change
+/// buffer always holds enough history for any dynamic lookback up to `30`.
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{DynamicMomentumIndex, Indicator};
+///
+/// let mut dmi = DynamicMomentumIndex::new(14).unwrap();
+/// let mut last = None;
+/// for i in 0..80 {
+///     last = dmi.update(100.0 + (f64::from(i) * 0.2).sin() * 5.0);
+/// }
+/// assert!(last.is_some());
+/// ```
+#[derive(Debug, Clone)]
+pub struct DynamicMomentumIndex {
+    period: usize,
+    vol: StdDev,
+    vol_avg: Sma,
+    prev_close: Option<f64>,
+    /// The last `MAX_PERIOD` price changes, oldest at the front.
+    changes: VecDeque<f64>,
+    last_vol_avg: Option<f64>,
+    last_value: Option<f64>,
+}
+
+impl DynamicMomentumIndex {
+    /// Construct a DMI with the given base RSI period (Chande uses 14).
+    ///
+    /// # Errors
+    ///
+    /// Returns [`Error::PeriodZero`] if `period == 0`.
+    pub fn new(period: usize) -> Result<Self> {
+        if period == 0 {
+            return Err(Error::PeriodZero);
+        }
+        Ok(Self {
+            period,
+            vol: StdDev::new(STD_PERIOD)?,
+            vol_avg: Sma::new(STD_AVG_PERIOD)?,
+            prev_close: None,
+            changes: VecDeque::with_capacity(MAX_PERIOD),
+            last_vol_avg: None,
+            last_value: None,
+        })
+    }
+
+    /// Configured base period.
+    pub const fn period(&self) -> usize {
+        self.period
+    }
+
+    /// Current value if available.
+    pub const fn value(&self) -> Option<f64> {
+        self.last_value
+    }
+
+    /// Dynamic lookback for the current volatility, clamped to `[5, 30]`.
+    fn dynamic_period(&self, vol: f64, vol_avg: f64) -> usize {
+        if vol_avg <= 0.0 || vol <= 0.0 {
+            // No measurable volatility -> slowest (calmest) lookback.
+            return MAX_PERIOD;
+        }
+        let vi = vol / vol_avg;
+        let td = (self.period as f64 / vi).round();
+        // td is finite and positive here; clamp into the valid band.
+        (td as usize).clamp(MIN_PERIOD, MAX_PERIOD)
+    }
+}
+
+impl Indicator for DynamicMomentumIndex {
+    type Input = f64;
+    type Output = f64;
+
+    fn update(&mut self, input: f64) -> Option<f64> {
+        if !input.is_finite() {
+            return self.last_value;
+        }
+        // Track the smoothed volatility on every close.
+        if let Some(v) = self.vol.update(input) {
+            self.last_vol_avg = self.vol_avg.update(v);
+        }
+
+        // Record the price change.
+        if let Some(prev) = self.prev_close {
+            let change = input - prev;
+            if self.changes.len() == MAX_PERIOD {
+                self.changes.pop_front();
+            }
+            self.changes.push_back(change);
+        }
+        self.prev_close = Some(input);
+
+        let vol = self.vol.value()?;
+        let vol_avg = self.last_vol_avg?;
+        if self.changes.len() < MAX_PERIOD {
+            return None;
+        }
+
+        let td = self.dynamic_period(vol, vol_avg);
+        // Average gains and losses over the last `td` changes.
+        let mut sum_gain = 0.0;
+        let mut sum_loss = 0.0;
+        for &c in self.changes.iter().skip(MAX_PERIOD - td) {
+            if c > 0.0 {
+                sum_gain += c;
+            } else if c < 0.0 {
+                sum_loss -= c;
+            }
+        }
+        let denom = sum_gain + sum_loss;
+        let v = if denom == 0.0 {
+            50.0
+        } else {
+            // Ratio first, then scale, so `100 * g / g` cannot round above 100.
+            100.0 * (sum_gain / denom)
+        };
+        self.last_value = Some(v);
+        Some(v)
+    }
+
+    fn reset(&mut self) {
+        self.vol.reset();
+        self.vol_avg.reset();
+        self.prev_close = None;
+        self.changes.clear();
+        self.last_vol_avg = None;
+        self.last_value = None;
+    }
+
+    fn warmup_period(&self) -> usize {
+        // The change buffer (MAX_PERIOD changes => MAX_PERIOD + 1 inputs) is the
+        // binding constraint; the volatility chain (5 + 10 - 1 = 14) is shorter.
+        MAX_PERIOD + 1
+    }
+
+    fn is_ready(&self) -> bool {
+        self.last_value.is_some()
+    }
+
+    fn name(&self) -> &'static str {
+        "DynamicMomentumIndex"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    #[test]
+    fn rejects_zero_period() {
+        assert!(matches!(
+            DynamicMomentumIndex::new(0),
+            Err(Error::PeriodZero)
+        ));
+    }
+
+    /// Cover the const accessors `period` + `value` and the Indicator-impl
+    /// `warmup_period` + `name`.
+    #[test]
+    fn accessors_and_metadata() {
+        let dmi = DynamicMomentumIndex::new(14).unwrap();
+        assert_eq!(dmi.period(), 14);
+        assert_eq!(dmi.value(), None);
+        assert_eq!(dmi.warmup_period(), 31);
+        assert_eq!(dmi.name(), "DynamicMomentumIndex");
+    }
+
+    #[test]
+    fn first_emission_matches_warmup_period() {
+        let prices: Vec<f64> = (0..50)
+            .map(|i| 100.0 + (f64::from(i) * 0.4).sin() * 6.0)
+            .collect();
+        let mut dmi = DynamicMomentumIndex::new(14).unwrap();
+        let out = dmi.batch(&prices);
+        for (i, v) in out.iter().enumerate().take(30) {
+            assert!(v.is_none(), "index {i} must be None during warmup");
+        }
+        assert!(out[30].is_some(), "first value at warmup_period - 1 = 30");
+    }
+
+    #[test]
+    fn pure_uptrend_is_one_hundred() {
+        // Every change positive -> avg_loss 0 -> 100, regardless of dynamic period.
+        let prices: Vec<f64> = (1..=60).map(f64::from).collect();
+        let mut dmi = DynamicMomentumIndex::new(14).unwrap();
+        let last = dmi.batch(&prices).into_iter().flatten().last().unwrap();
+        assert_relative_eq!(last, 100.0, epsilon = 1e-9);
+    }
+
+    #[test]
+    fn flat_market_is_neutral() {
+        // Constant prices: no volatility (dynamic period -> max) and no changes
+        // -> neutral 50.
+        let mut dmi = DynamicMomentumIndex::new(14).unwrap();
+        let last = dmi.batch(&[42.0; 50]).into_iter().flatten().last().unwrap();
+        assert_relative_eq!(last, 50.0, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn output_stays_in_range() {
+        let prices: Vec<f64> = (0..120)
+            .map(|i| 100.0 + (f64::from(i) * 0.3).sin() * 10.0 + (f64::from(i) * 0.07).cos() * 4.0)
+            .collect();
+        let mut dmi = DynamicMomentumIndex::new(14).unwrap();
+        for v in dmi.batch(&prices).into_iter().flatten() {
+            assert!((0.0..=100.0).contains(&v), "DMI {v} left [0, 100]");
+        }
+    }
+
+    #[test]
+    fn high_volatility_shortens_period() {
+        let dmi = DynamicMomentumIndex::new(14).unwrap();
+        // Vi = 2 (vol twice its average) -> td = round(14 / 2) = 7.
+        assert_eq!(dmi.dynamic_period(2.0, 1.0), 7);
+        // Vi = 0.5 (calm) -> td = round(14 / 0.5) = 28.
+        assert_eq!(dmi.dynamic_period(0.5, 1.0), 28);
+        // Extreme calm clamps to MAX_PERIOD; extreme volatility clamps to MIN.
+        assert_eq!(dmi.dynamic_period(0.1, 1.0), MAX_PERIOD);
+        assert_eq!(dmi.dynamic_period(100.0, 1.0), MIN_PERIOD);
+        // Zero volatility -> slowest lookback.
+        assert_eq!(dmi.dynamic_period(0.0, 1.0), MAX_PERIOD);
+        assert_eq!(dmi.dynamic_period(1.0, 0.0), MAX_PERIOD);
+    }
+
+    #[test]
+    fn ignores_non_finite_input() {
+        let mut dmi = DynamicMomentumIndex::new(14).unwrap();
+        let ready = dmi
+            .batch(&(0..40).map(|i| 100.0 + f64::from(i)).collect::<Vec<_>>())
+            .into_iter()
+            .flatten()
+            .last()
+            .unwrap();
+        assert_eq!(dmi.update(f64::NAN), Some(ready));
+        assert_eq!(dmi.update(f64::INFINITY), Some(ready));
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut dmi = DynamicMomentumIndex::new(14).unwrap();
+        dmi.batch(&(0..40).map(|i| 100.0 + f64::from(i)).collect::<Vec<_>>());
+        assert!(dmi.is_ready());
+        dmi.reset();
+        assert!(!dmi.is_ready());
+        assert_eq!(dmi.update(1.0), None);
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let prices: Vec<f64> = (0..80)
+            .map(|i| 50.0 + (f64::from(i) * 0.5).sin() * 10.0)
+            .collect();
+        let mut a = DynamicMomentumIndex::new(14).unwrap();
+        let mut b = DynamicMomentumIndex::new(14).unwrap();
+        assert_eq!(
+            a.batch(&prices),
+            prices.iter().map(|p| b.update(*p)).collect::<Vec<_>>()
+        );
+    }
+}
@@ -0,0 +1,202 @@
+//! Exponential Hull Moving Average (EHMA).
+
+use crate::error::{Error, Result};
+use crate::indicators::ema::Ema;
+use crate::traits::Indicator;
+
+/// Exponential Hull Moving Average: the Hull construction built from EMAs
+/// instead of WMAs.
+///
+/// ```text
+/// EHMA = EMA( 2 · EMA(price, period/2) − EMA(price, period), round(sqrt(period)) )
+/// ```
+///
+/// Alan Hull's [`Hma`](crate::Hma) uses weighted moving averages; replacing them
+/// with exponential moving averages keeps the same lag-reduction trick — a fast
+/// half-length average minus a full-length one, smoothed over `sqrt(period)` —
+/// while inheriting the EMA's strictly recursive O(1) update and infinite
+/// (exponentially decaying) memory. The result is marginally smoother than the
+/// WMA-based Hull at the cost of a little more lag.
+///
+/// The half period is `(period / 2).max(1)` and the smoothing period is
+/// `round(sqrt(period)).max(1)`, matching the rounding used by [`Hma`].
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Indicator, Ehma};
+///
+/// let mut indicator = Ehma::new(9).unwrap();
+/// let mut last = None;
+/// for i in 0..80 {
+///     last = indicator.update(100.0 + f64::from(i));
+/// }
+/// assert!(last.is_some());
+/// ```
+#[derive(Debug, Clone)]
+pub struct Ehma {
+    period: usize,
+    half_ema: Ema,
+    full_ema: Ema,
+    smooth_ema: Ema,
+}
+
+impl Ehma {
+    /// # Errors
+    /// Returns [`Error::PeriodZero`] if `period == 0`.
+    pub fn new(period: usize) -> Result<Self> {
+        if period == 0 {
+            return Err(Error::PeriodZero);
+        }
+        let half = (period / 2).max(1);
+        let smooth = (period as f64).sqrt().round() as usize;
+        let smooth = smooth.max(1);
+        Ok(Self {
+            period,
+            half_ema: Ema::new(half)?,
+            full_ema: Ema::new(period)?,
+            smooth_ema: Ema::new(smooth)?,
+        })
+    }
+
+    /// Configured period.
+    pub const fn period(&self) -> usize {
+        self.period
+    }
+}
+
+impl Indicator for Ehma {
+    type Input = f64;
+    type Output = f64;
+
+    fn update(&mut self, input: f64) -> Option<f64> {
+        // Feed both component EMAs on every input so they warm up in parallel;
+        // gating the longer one behind the shorter would delay the first
+        // emission past `warmup_period()`.
+        let h = self.half_ema.update(input);
+        let f = self.full_ema.update(input);
+        let (h, f) = (h?, f?);
+        let diff = 2.0 * h - f;
+        self.smooth_ema.update(diff)
+    }
+
+    fn reset(&mut self) {
+        self.half_ema.reset();
+        self.full_ema.reset();
+        self.smooth_ema.reset();
+    }
+
+    fn warmup_period(&self) -> usize {
+        // full_ema seeds at `period`, then smooth_ema needs another
+        // (round(sqrt(period)) - 1) values to seed.
+        let sm = (self.period as f64).sqrt().round() as usize;
+        self.period + sm.max(1) - 1
+    }
+
+    fn is_ready(&self) -> bool {
+        self.smooth_ema.is_ready()
+    }
+
+    fn name(&self) -> &'static str {
+        "EHMA"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    #[test]
+    fn constant_series_yields_constant_ehma() {
+        let mut ehma = Ehma::new(9).unwrap();
+        let out = ehma.batch(&[10.0_f64; 80]);
+        let last = out.iter().rev().flatten().next().unwrap();
+        assert_relative_eq!(*last, 10.0, epsilon = 1e-9);
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let prices: Vec<f64> = (1..=100).map(|i| f64::from(i) * 0.7).collect();
+        let mut a = Ehma::new(9).unwrap();
+        let mut b = Ehma::new(9).unwrap();
+        assert_eq!(
+            a.batch(&prices),
+            prices.iter().map(|p| b.update(*p)).collect::<Vec<_>>()
+        );
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut ehma = Ehma::new(9).unwrap();
+        ehma.batch(&(1..=80).map(f64::from).collect::<Vec<_>>());
+        assert!(ehma.is_ready());
+        ehma.reset();
+        assert!(!ehma.is_ready());
+    }
+
+    #[test]
+    fn rejects_zero_period() {
+        assert!(Ehma::new(0).is_err());
+    }
+
+    /// Cover the const accessor `period` and the Indicator-impl `name`.
+    /// `warmup_period` is covered by `first_emission_matches_warmup_period`.
+    #[test]
+    fn accessors_and_metadata() {
+        let ehma = Ehma::new(9).unwrap();
+        assert_eq!(ehma.period(), 9);
+        assert_eq!(ehma.name(), "EHMA");
+    }
+
+    #[test]
+    fn first_emission_matches_warmup_period() {
+        let prices: Vec<f64> = (1..=40).map(f64::from).collect();
+        let mut ehma = Ehma::new(9).unwrap();
+        let out = ehma.batch(&prices);
+        let warmup = ehma.warmup_period();
+        // full EMA seeds at 9, smooth EMA round(sqrt(9))=3 needs 2 more -> 11.
+        assert_eq!(warmup, 11);
+        for (i, v) in out.iter().enumerate().take(warmup - 1) {
+            assert!(v.is_none(), "index {i} must be None during warmup");
+        }
+        assert!(
+            out[warmup - 1].is_some(),
+            "first EHMA value must land at warmup_period - 1"
+        );
+    }
+
+    #[test]
+    fn matches_independent_emas() {
+        // The two component EMAs run as independent siblings on the price
+        // stream; EHMA must equal feeding three standalone EMAs and combining.
+        let prices: Vec<f64> = (1..=50)
+            .map(|i| (f64::from(i) * 0.3).sin() * 10.0 + 50.0)
+            .collect();
+        let mut ehma = Ehma::new(9).unwrap();
+        let mut half = Ema::new(4).unwrap(); // (9 / 2).max(1)
+        let mut full = Ema::new(9).unwrap();
+        let mut smooth = Ema::new(3).unwrap(); // round(sqrt(9))
+        for (i, &p) in prices.iter().enumerate() {
+            let got = ehma.update(p);
+            let want = match (half.update(p), full.update(p)) {
+                (Some(h), Some(f)) => smooth.update(2.0 * h - f),
+                _ => None,
+            };
+            assert_eq!(got.is_some(), want.is_some(), "readiness mismatch at {i}");
+            if let (Some(a), Some(b)) = (got, want) {
+                assert_relative_eq!(a, b, epsilon = 1e-9);
+            }
+        }
+    }
+
+    #[test]
+    fn period_one_collapses_to_pass_through() {
+        // period 1: half=1, full=1, smooth=round(sqrt(1))=1; every EMA seeds on
+        // the first input, so EHMA(1) passes the price straight through.
+        let mut ehma = Ehma::new(1).unwrap();
+        assert_relative_eq!(ehma.update(5.0).unwrap(), 5.0, epsilon = 1e-12);
+        assert_relative_eq!(ehma.update(8.0).unwrap(), 8.0, epsilon = 1e-12);
+    }
+}
@@ -0,0 +1,192 @@
+//! Elder Ray — Bull Power and Bear Power.
+
+use crate::error::Result;
+use crate::indicators::ema::Ema;
+use crate::ohlcv::Candle;
+use crate::traits::Indicator;
+
+/// One Elder Ray reading: the bull and bear power for a bar.
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub struct ElderRayOutput {
+    /// `high − EMA(close)`: how far buyers pushed price above the trend mean.
+    pub bull_power: f64,
+    /// `low − EMA(close)`: how far sellers pushed price below the trend mean
+    /// (negative in a normal market).
+    pub bear_power: f64,
+}
+
+/// Elder Ray — Alexander Elder's Bull Power / Bear Power oscillator.
+///
+/// An EMA of the close marks the market's consensus of value; the bar's high and
+/// low relative to it measure how far the bulls and bears could push price away
+/// from that consensus:
+///
+/// ```text
+/// ema       = EMA(close, period)
+/// BullPower = high - ema
+/// BearPower = low  - ema
+/// ```
+///
+/// Bull Power is normally positive (the high prints above the mean) and Bear
+/// Power normally negative (the low prints below it). Their behaviour relative
+/// to zero and to the EMA's slope drives Elder's signals: e.g. in an uptrend
+/// (rising EMA), a bounce in a negative-but-rising Bear Power is a buy setup.
+///
+/// The first reading lands once the inner EMA is seeded, at bar `period`.
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Candle, ElderRay, Indicator};
+///
+/// let mut er = ElderRay::new(13).unwrap();
+/// let mut last = None;
+/// for i in 0..40 {
+///     let base = 100.0 + f64::from(i);
+///     let c = Candle::new(base, base + 2.0, base - 2.0, base + 0.5, 1.0, i64::from(i)).unwrap();
+///     last = er.update(c);
+/// }
+/// assert!(last.is_some());
+/// ```
+#[derive(Debug, Clone)]
+pub struct ElderRay {
+    period: usize,
+    ema: Ema,
+}
+
+impl ElderRay {
+    /// Construct an Elder Ray with the given EMA period.
+    ///
+    /// # Errors
+    ///
+    /// Returns [`crate::Error::PeriodZero`] if `period == 0`.
+    pub fn new(period: usize) -> Result<Self> {
+        Ok(Self {
+            period,
+            ema: Ema::new(period)?,
+        })
+    }
+
+    /// Configured period.
+    pub const fn period(&self) -> usize {
+        self.period
+    }
+}
+
+impl Indicator for ElderRay {
+    type Input = Candle;
+    type Output = ElderRayOutput;
+
+    fn update(&mut self, candle: Candle) -> Option<ElderRayOutput> {
+        let ema = self.ema.update(candle.close)?;
+        Some(ElderRayOutput {
+            bull_power: candle.high - ema,
+            bear_power: candle.low - ema,
+        })
+    }
+
+    fn reset(&mut self) {
+        self.ema.reset();
+    }
+
+    fn warmup_period(&self) -> usize {
+        self.period
+    }
+
+    fn is_ready(&self) -> bool {
+        self.ema.is_ready()
+    }
+
+    fn name(&self) -> &'static str {
+        "ElderRay"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    fn candle(high: f64, low: f64, close: f64) -> Candle {
+        Candle::new(close, high, low, close, 1.0, 0).unwrap()
+    }
+
+    #[test]
+    fn rejects_zero_period() {
+        assert!(ElderRay::new(0).is_err());
+    }
+
+    /// Cover the const accessor `period` and the Indicator-impl `warmup_period`
+    /// + `name`.
+    #[test]
+    fn accessors_and_metadata() {
+        let er = ElderRay::new(13).unwrap();
+        assert_eq!(er.period(), 13);
+        assert_eq!(er.warmup_period(), 13);
+        assert_eq!(er.name(), "ElderRay");
+    }
+
+    #[test]
+    fn warmup_then_known_value() {
+        // EMA(3) seeds at bar 3 with SMA([10,12,14]) = 12 (closes).
+        // bar 3: high 16, low 13 -> bull = 16 - 12 = 4, bear = 13 - 12 = 1.
+        let mut er = ElderRay::new(3).unwrap();
+        assert_eq!(er.update(candle(11.0, 9.0, 10.0)), None);
+        assert_eq!(er.update(candle(13.0, 11.0, 12.0)), None);
+        let v = er.update(candle(16.0, 13.0, 14.0)).unwrap();
+        assert_relative_eq!(v.bull_power, 4.0, epsilon = 1e-12);
+        assert_relative_eq!(v.bear_power, 1.0, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn matches_manual_ema() {
+        let bars: Vec<Candle> = (0..40)
+            .map(|i| {
+                let base = 100.0 + (f64::from(i) * 0.3).sin() * 5.0;
+                candle(base + 2.0, base - 2.0, base)
+            })
+            .collect();
+        let mut er = ElderRay::new(13).unwrap();
+        let mut ema = Ema::new(13).unwrap();
+        for (i, c) in bars.iter().enumerate() {
+            let got = er.update(*c);
+            let want = ema.update(c.close).map(|e| (c.high - e, c.low - e));
+            assert_eq!(got.is_some(), want.is_some(), "readiness mismatch at {i}");
+            if let (Some(g), Some((b, be))) = (got, want) {
+                assert_relative_eq!(g.bull_power, b, epsilon = 1e-9);
+                assert_relative_eq!(g.bear_power, be, epsilon = 1e-9);
+            }
+        }
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut er = ElderRay::new(5).unwrap();
+        er.batch(
+            &(0..20)
+                .map(|i| candle(f64::from(i) + 1.0, f64::from(i) - 1.0, f64::from(i)))
+                .collect::<Vec<_>>(),
+        );
+        assert!(er.is_ready());
+        er.reset();
+        assert!(!er.is_ready());
+        assert_eq!(er.update(candle(2.0, 0.0, 1.0)), None);
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let bars: Vec<Candle> = (0..30)
+            .map(|i| {
+                let base = 50.0 + f64::from(i);
+                candle(base + 1.5, base - 1.5, base)
+            })
+            .collect();
+        let mut a = ElderRay::new(7).unwrap();
+        let mut b = ElderRay::new(7).unwrap();
+        assert_eq!(
+            a.batch(&bars),
+            bars.iter().map(|c| b.update(*c)).collect::<Vec<_>>()
+        );
+    }
+}
@@ -0,0 +1,360 @@
+//! Elder `SafeZone` Stop — a trailing stop set by the average noise penetration.
+
+use std::collections::VecDeque;
+
+use crate::error::{Error, Result};
+use crate::ohlcv::Candle;
+use crate::traits::Indicator;
+
+/// Output of [`ElderSafeZone`]: the active stop level and the trend direction.
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub struct ElderSafeZoneOutput {
+    /// The `SafeZone` stop level — below price when long, above price when short.
+    pub value: f64,
+    /// Trend direction: `+1.0` long, `-1.0` short.
+    pub direction: f64,
+}
+
+/// Elder `SafeZone` Stop — Alexander Elder's stop placed a multiple of the
+/// **average market noise** away from price.
+///
+/// ```text
+/// long  market noise = average downside penetration = mean( prev_low − low | low < prev_low )
+/// short market noise = average upside  penetration = mean( high − prev_high | high > prev_high )
+/// long  stop = ratchet_up(   low_t  − coeff · avg_down_penetration )
+/// short stop = ratchet_down( high_t + coeff · avg_up_penetration   )
+/// ```
+///
+/// Elder defines *noise* in an uptrend as the part of each bar that pokes below
+/// the previous bar's low (a "downside penetration"). Averaging those
+/// penetrations over a lookback and placing the stop `coeff` multiples below the
+/// current low keeps the stop just outside normal pullbacks while still exiting on
+/// a genuine reversal. The stop trails in the trend's favour and flips when price
+/// closes through it. The average uses only the bars that actually penetrated
+/// (Elder's definition), so a noiseless trend gives a tight stop at the bar's
+/// extreme.
+///
+/// The first bar seeds the prior candle; the next `period` bars accumulate the
+/// penetration statistics, so the first stop lands after `period + 1` inputs.
+/// Each `update` is O(1).
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Candle, Indicator, ElderSafeZone};
+///
+/// let mut indicator = ElderSafeZone::new(14, 2.0).unwrap();
+/// let mut last = None;
+/// for i in 0..60 {
+///     let base = 100.0 + f64::from(i);
+///     let c = Candle::new(base, base + 2.0, base - 2.0, base + 1.0, 1_000.0, 0).unwrap();
+///     last = indicator.update(c);
+/// }
+/// assert!(last.is_some());
+/// ```
+#[derive(Debug, Clone)]
+pub struct ElderSafeZone {
+    period: usize,
+    coeff: f64,
+    prev: Option<Candle>,
+    down_pen: VecDeque<f64>,
+    up_pen: VecDeque<f64>,
+    down_sum: f64,
+    up_sum: f64,
+    down_count: usize,
+    up_count: usize,
+    direction: f64,
+    stop: f64,
+    last: Option<ElderSafeZoneOutput>,
+}
+
+impl ElderSafeZone {
+    /// Construct an Elder `SafeZone` stop with the given averaging `period` and
+    /// noise `coeff`icient.
+    ///
+    /// # Errors
+    ///
+    /// Returns [`Error::PeriodZero`] if `period == 0` and
+    /// [`Error::NonPositiveMultiplier`] if `coeff` is not finite and positive.
+    pub fn new(period: usize, coeff: f64) -> Result<Self> {
+        if period == 0 {
+            return Err(Error::PeriodZero);
+        }
+        if !coeff.is_finite() || coeff <= 0.0 {
+            return Err(Error::NonPositiveMultiplier);
+        }
+        Ok(Self {
+            period,
+            coeff,
+            prev: None,
+            down_pen: VecDeque::with_capacity(period),
+            up_pen: VecDeque::with_capacity(period),
+            down_sum: 0.0,
+            up_sum: 0.0,
+            down_count: 0,
+            up_count: 0,
+            direction: 0.0,
+            stop: 0.0,
+            last: None,
+        })
+    }
+
+    /// Configured `(period, coeff)`.
+    pub const fn params(&self) -> (usize, f64) {
+        (self.period, self.coeff)
+    }
+
+    /// Current value if available.
+    pub const fn value(&self) -> Option<ElderSafeZoneOutput> {
+        self.last
+    }
+
+    fn push(window: &mut VecDeque<f64>, sum: &mut f64, count: &mut usize, period: usize, pen: f64) {
+        if window.len() == period {
+            let old = window.pop_front().expect("non-empty");
+            *sum -= old;
+            if old > 0.0 {
+                *count -= 1;
+            }
+        }
+        window.push_back(pen);
+        *sum += pen;
+        if pen > 0.0 {
+            *count += 1;
+        }
+    }
+
+    fn avg(sum: f64, count: usize) -> f64 {
+        if count == 0 {
+            0.0
+        } else {
+            sum / count as f64
+        }
+    }
+}
+
+impl Indicator for ElderSafeZone {
+    type Input = Candle;
+    type Output = ElderSafeZoneOutput;
+
+    fn update(&mut self, candle: Candle) -> Option<ElderSafeZoneOutput> {
+        let Some(prev) = self.prev else {
+            self.prev = Some(candle);
+            return None;
+        };
+        let dp = (prev.low - candle.low).max(0.0);
+        let up = (candle.high - prev.high).max(0.0);
+        self.prev = Some(candle);
+
+        Self::push(
+            &mut self.down_pen,
+            &mut self.down_sum,
+            &mut self.down_count,
+            self.period,
+            dp,
+        );
+        Self::push(
+            &mut self.up_pen,
+            &mut self.up_sum,
+            &mut self.up_count,
+            self.period,
+            up,
+        );
+        if self.down_pen.len() < self.period {
+            return None;
+        }
+
+        let avg_down = Self::avg(self.down_sum, self.down_count);
+        let avg_up = Self::avg(self.up_sum, self.up_count);
+
+        if self.direction == 0.0 {
+            self.direction = 1.0;
+            self.stop = candle.low - self.coeff * avg_down;
+        } else if self.direction > 0.0 {
+            let raw = candle.low - self.coeff * avg_down;
+            self.stop = self.stop.max(raw);
+            if candle.close < self.stop {
+                self.direction = -1.0;
+                self.stop = candle.high + self.coeff * avg_up;
+            }
+        } else {
+            let raw = candle.high + self.coeff * avg_up;
+            self.stop = self.stop.min(raw);
+            if candle.close > self.stop {
+                self.direction = 1.0;
+                self.stop = candle.low - self.coeff * avg_down;
+            }
+        }
+
+        let out = ElderSafeZoneOutput {
+            value: self.stop,
+            direction: self.direction,
+        };
+        self.last = Some(out);
+        Some(out)
+    }
+
+    fn reset(&mut self) {
+        self.prev = None;
+        self.down_pen.clear();
+        self.up_pen.clear();
+        self.down_sum = 0.0;
+        self.up_sum = 0.0;
+        self.down_count = 0;
+        self.up_count = 0;
+        self.direction = 0.0;
+        self.stop = 0.0;
+        self.last = None;
+    }
+
+    fn warmup_period(&self) -> usize {
+        self.period + 1
+    }
+
+    fn is_ready(&self) -> bool {
+        self.last.is_some()
+    }
+
+    fn name(&self) -> &'static str {
+        "ElderSafeZone"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+
+    fn c(high: f64, low: f64, close: f64) -> Candle {
+        Candle::new_unchecked(f64::midpoint(high, low), high, low, close, 1_000.0, 0)
+    }
+
+    #[test]
+    fn rejects_invalid_params() {
+        assert!(matches!(ElderSafeZone::new(0, 2.0), Err(Error::PeriodZero)));
+        assert!(matches!(
+            ElderSafeZone::new(14, 0.0),
+            Err(Error::NonPositiveMultiplier)
+        ));
+        assert!(matches!(
+            ElderSafeZone::new(14, -1.0),
+            Err(Error::NonPositiveMultiplier)
+        ));
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let e = ElderSafeZone::new(14, 2.0).unwrap();
+        assert_eq!(e.params(), (14, 2.0));
+        assert_eq!(e.warmup_period(), 15);
+        assert_eq!(e.name(), "ElderSafeZone");
+        assert!(!e.is_ready());
+        assert_eq!(e.value(), None);
+    }
+
+    #[test]
+    fn first_emission_at_warmup_period() {
+        let mut e = ElderSafeZone::new(3, 2.0).unwrap();
+        let candles: Vec<Candle> = (0..8)
+            .map(|i| {
+                let base = 100.0 + f64::from(i);
+                c(base + 1.0, base - 1.0, base)
+            })
+            .collect();
+        let out = e.batch(&candles);
+        let warmup = e.warmup_period(); // 4
+        assert_eq!(warmup, 4);
+        for v in out.iter().take(warmup - 1) {
+            assert!(v.is_none());
+        }
+        assert!(out[warmup - 1].is_some());
+    }
+
+    #[test]
+    fn uptrend_keeps_stop_below_price() {
+        let mut e = ElderSafeZone::new(5, 2.0).unwrap();
+        let candles: Vec<Candle> = (0..60)
+            .map(|i| {
+                let base = 100.0 + 2.0 * f64::from(i);
+                c(base + 1.0, base - 1.0, base + 0.5)
+            })
+            .collect();
+        for (o, candle) in e.batch(&candles).into_iter().zip(candles.iter()) {
+            if let Some(o) = o {
+                assert_eq!(o.direction, 1.0);
+                assert!(o.value <= candle.close);
+            }
+        }
+    }
+
+    #[test]
+    fn noiseless_trend_stop_sits_at_low() {
+        // Every bar makes a higher low -> no downside penetration -> avg 0 ->
+        // the stop sits exactly at the bar's low.
+        let mut e = ElderSafeZone::new(3, 2.0).unwrap();
+        let candles: Vec<Candle> = (0..10)
+            .map(|i| {
+                let base = 100.0 + f64::from(i);
+                c(base + 1.0, base - 1.0, base + 0.5)
+            })
+            .collect();
+        let out = e.batch(&candles);
+        let last_candle = candles.last().unwrap();
+        let last = out.last().unwrap().unwrap();
+        assert!((last.value - last_candle.low).abs() < 1e-9);
+    }
+
+    #[test]
+    fn flips_on_reversal() {
+        let mut candles: Vec<Candle> = (0..40)
+            .map(|i| {
+                let base = 100.0 + f64::from(i);
+                c(base + 1.0, base - 1.0, base + 0.5)
+            })
+            .collect();
+        candles.extend((0..40).map(|i| {
+            let base = 140.0 - f64::from(i);
+            c(base + 1.0, base - 1.0, base - 0.5)
+        }));
+        let mut e = ElderSafeZone::new(5, 2.0).unwrap();
+        let dirs: Vec<f64> = e
+            .batch(&candles)
+            .into_iter()
+            .flatten()
+            .map(|o| o.direction)
+            .collect();
+        assert!(dirs.iter().any(|&d| d > 0.0));
+        assert!(dirs.iter().any(|&d| d < 0.0));
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut e = ElderSafeZone::new(5, 2.0).unwrap();
+        let candles: Vec<Candle> = (0..40)
+            .map(|i| {
+                let base = 100.0 + f64::from(i);
+                c(base + 1.0, base - 1.0, base + 0.5)
+            })
+            .collect();
+        e.batch(&candles);
+        assert!(e.is_ready());
+        e.reset();
+        assert!(!e.is_ready());
+        assert_eq!(e.value(), None);
+        assert_eq!(e.update(candles[0]), None);
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let candles: Vec<Candle> = (0..120)
+            .map(|i| {
+                let base = 100.0 + (f64::from(i) * 0.25).sin() * 9.0;
+                c(base + 2.0, base - 1.5, base + 0.5)
+            })
+            .collect();
+        let batch = ElderSafeZone::new(14, 2.0).unwrap().batch(&candles);
+        let mut b = ElderSafeZone::new(14, 2.0).unwrap();
+        let streamed: Vec<_> = candles.iter().map(|c| b.update(*c)).collect();
+        assert_eq!(batch, streamed);
+    }
+}
@@ -25,7 +25,15 @@ use crate::traits::Indicator;
 pub struct Ema {
    period: usize,
    alpha: f64,
-    state: Option<f64>,
+    /// `1 - alpha`, precomputed so the recurrence avoids a subtraction per tick.
+    /// Cached value, so the steady-state output is bit-for-bit unchanged.
+    one_minus_alpha: f64,
+    /// Latest EMA value, valid only once `seeded` is true. Stored as a bare `f64`
+    /// (plus the `seeded` flag) rather than `Option<f64>` so the steady-state
+    /// recurrence reads and writes 8 bytes with no enum-tag handling per tick.
+    current: f64,
+    /// Whether `current` holds a real value yet (warmup complete).
+    seeded: bool,
    warmup_buf: Vec<f64>,
 }

@@ -43,7 +51,9 @@ impl Ema {
        Ok(Self {
            period,
            alpha,
-            state: None,
+            one_minus_alpha: 1.0 - alpha,
+            current: 0.0,
+            seeded: false,
            warmup_buf: Vec::with_capacity(period),
        })
    }
@@ -66,7 +76,9 @@ impl Ema {
        Ok(Self {
            period: 1,
            alpha,
-            state: None,
+            one_minus_alpha: 1.0 - alpha,
+            current: 0.0,
+            seeded: false,
            warmup_buf: Vec::with_capacity(1),
        })
    }
@@ -83,21 +95,90 @@ impl Ema {

    /// Current value if available.
    pub const fn value(&self) -> Option<f64> {
-        self.state
+        if self.seeded {
+            Some(self.current)
+        } else {
+            None
+        }
+    }
+
+    /// Whether the EMA has seen no input yet (neither seeded nor mid-warmup).
+    /// Lets composite indicators (e.g. MACD) decide if a fast batch path is safe.
+    pub(crate) fn is_fresh(&self) -> bool {
+        !self.seeded && self.warmup_buf.is_empty()
+    }
+
+    /// Force the EMA into its seeded steady state with `current` as the latest
+    /// value. Used by composite fused batch paths (MACD) to leave each sub-EMA
+    /// where a per-tick `update` replay would, so a later `update` continues
+    /// correctly. The post-seed recurrence never re-reads `warmup_buf`, so it is
+    /// left as-is.
+    pub(crate) fn seed_to(&mut self, current: f64) {
+        self.current = current;
+        self.seeded = true;
+    }
+
+    /// Vectorized batch returning one `f64` per input (`NaN` during warmup).
+    ///
+    /// Shadows the generic [`BatchNanExt::batch_nan`](crate::BatchNanExt) blanket
+    /// default via inherent-method resolution. For a fresh indicator over an
+    /// all-finite slice it runs the seed (mean of the first `period`) once and
+    /// then the bare `alpha * x + (1 - alpha) * prev` recurrence in a tight loop
+    /// with no per-element `is_finite`/`seeded` branch and no `Option` — yet uses
+    /// the identical `mul_add`, so the result is *bit-for-bit* equal to replaying
+    /// `update`. Any other state, or a non-finite element, defers to the exact
+    /// `update` replay.
+    pub fn batch_nan(&mut self, inputs: &[f64]) -> Vec<f64> {
+        let p = self.period;
+        if self.seeded || !self.warmup_buf.is_empty() || !inputs.iter().all(|x| x.is_finite()) {
+            return inputs
+                .iter()
+                .map(|&x| self.update(x).unwrap_or(f64::NAN))
+                .collect();
+        }
+
+        let n = inputs.len();
+        if n < p {
+            // Not enough to seed; mirror `update` stashing inputs for warmup.
+            self.warmup_buf.extend_from_slice(inputs);
+            return vec![f64::NAN; n];
+        }
+
+        // Warmup `[0, p-1)` is `NaN`; values from the seed on are pushed once each.
+        let mut out = vec![f64::NAN; p - 1];
+        out.reserve(n - (p - 1));
+        let seed = inputs[..p].iter().copied().sum::<f64>() / p as f64;
+        let mut cur = seed;
+        out.push(seed);
+        let (alpha, oma) = (self.alpha, self.one_minus_alpha);
+        for &x in &inputs[p..] {
+            cur = alpha.mul_add(x, oma * cur);
+            out.push(cur);
+        }
+
+        // Leave state exactly where `update` would: seeded on `current`, with the
+        // first `period` inputs retained in `warmup_buf` (never cleared post-seed).
+        self.current = cur;
+        self.seeded = true;
+        self.warmup_buf.extend_from_slice(&inputs[..p]);
+        out
    }

    /// Internal helper that feeds a value without finiteness validation. The caller
    /// guarantees `input.is_finite()`. Used by MACD which has already validated.
    pub(crate) fn step_unchecked(&mut self, input: f64) -> Option<f64> {
-        if let Some(prev) = self.state {
-            let new = self.alpha.mul_add(input, (1.0 - self.alpha) * prev);
-            self.state = Some(new);
+        if self.seeded {
+            let new = self
+                .alpha
+                .mul_add(input, self.one_minus_alpha * self.current);
+            self.current = new;
            return Some(new);
        }
        self.warmup_buf.push(input);
        if self.warmup_buf.len() == self.period {
            let seed = self.warmup_buf.iter().copied().sum::<f64>() / self.period as f64;
-            self.state = Some(seed);
+            self.current = seed;
+            self.seeded = true;
            return Some(seed);
        }
        None
@@ -110,13 +191,14 @@ impl Indicator for Ema {

    fn update(&mut self, input: f64) -> Option<f64> {
        if !input.is_finite() {
-            return self.state;
+            return self.value();
        }
        self.step_unchecked(input)
    }

    fn reset(&mut self) {
-        self.state = None;
+        self.current = 0.0;
+        self.seeded = false;
        self.warmup_buf.clear();
    }

@@ -125,7 +207,7 @@ impl Indicator for Ema {
    }

    fn is_ready(&self) -> bool {
-        self.state.is_some()
+        self.seeded
    }

    fn name(&self) -> &'static str {
@@ -268,6 +350,71 @@ mod tests {
        assert_eq!(ema.update(f64::INFINITY), before);
    }

+    fn bits_eq(a: &[f64], b: &[f64]) -> bool {
+        a.len() == b.len()
+            && a.iter()
+                .zip(b)
+                .all(|(x, y)| x == y || (x.is_nan() && y.is_nan()))
+    }
+
+    fn ema_replay(period: usize, series: &[f64]) -> Vec<f64> {
+        let mut e = Ema::new(period).unwrap();
+        series
+            .iter()
+            .map(|&x| e.update(x).unwrap_or(f64::NAN))
+            .collect()
+    }
+
+    #[test]
+    fn batch_nan_fast_path_is_bit_identical() {
+        let series: Vec<f64> = (0..300)
+            .map(|i| (f64::from(i) * 0.25).cos() * 8.0 + 40.0)
+            .collect();
+        let mut ema = Ema::new(14).unwrap();
+        let got = ema.batch_nan(&series);
+        assert!(bits_eq(&got, &ema_replay(14, &series)));
+        let mut ref_ema = Ema::new(14).unwrap();
+        for &x in &series {
+            ref_ema.update(x);
+        }
+        assert_eq!(ema.update(7.5), ref_ema.update(7.5));
+    }
+
+    #[test]
+    fn batch_nan_falls_back_on_non_finite() {
+        let series = [1.0, 2.0, 3.0, f64::INFINITY, 5.0, 6.0, 7.0];
+        let mut ema = Ema::new(3).unwrap();
+        assert!(bits_eq(&ema.batch_nan(&series), &ema_replay(3, &series)));
+    }
+
+    #[test]
+    fn batch_nan_falls_back_when_warming() {
+        let mut ema = Ema::new(3).unwrap();
+        ema.update(10.0); // mid-warmup: warmup_buf non-empty, not seeded
+        let series = [1.0, 2.0, 3.0, 4.0];
+        let mut ref_ema = Ema::new(3).unwrap();
+        ref_ema.update(10.0);
+        let want: Vec<f64> = series
+            .iter()
+            .map(|&x| ref_ema.update(x).unwrap_or(f64::NAN))
+            .collect();
+        assert!(bits_eq(&ema.batch_nan(&series), &want));
+    }
+
+    #[test]
+    fn batch_nan_sub_period_slice_stays_unseeded() {
+        let series = [1.0, 2.0];
+        let mut ema = Ema::new(5).unwrap();
+        let got = ema.batch_nan(&series);
+        assert!(got.iter().all(|x| x.is_nan()) && got.len() == 2);
+        assert!(!ema.is_ready());
+        // Warmup state was stashed: feeding the rest seeds exactly as a full stream.
+        assert!(bits_eq(
+            &[ema.update(3.0).unwrap_or(f64::NAN)],
+            &[ema_replay(5, &[1.0, 2.0, 3.0])[2]]
+        ));
+    }
+
    proptest::proptest! {
        #![proptest_config(proptest::test_runner::Config::with_cases(48))]
        #[test]
@@ -0,0 +1,269 @@
+//! Ehlers Even Better Sinewave (EBSW) — a normalised cycle oscillator in [-1, 1].
+#![allow(clippy::doc_markdown)]
+
+use std::f64::consts::PI;
+
+use crate::error::{Error, Result};
+use crate::indicators::super_smoother::SuperSmoother;
+use crate::traits::Indicator;
+
+/// Ehlers' **Even Better Sinewave** (EBSW) — a self-normalising cycle oscillator
+/// that swings cleanly in `[−1, +1]` regardless of price amplitude.
+///
+/// From John Ehlers' *Cycle Analytics for Traders* (2013, ch. 12):
+///
+/// ```text
+/// alpha1 = (1 − sin(2π/hp_period)) / cos(2π/hp_period)
+/// HP_t   = 0.5·(1 + alpha1)·(price_t − price_{t−1}) + alpha1·HP_{t−1}   (one-pole highpass)
+/// Filt   = SuperSmoother(HP, ssf_length)
+/// Wave   = (Filt_t + Filt_{t−1} + Filt_{t−2}) / 3
+/// Pwr    = (Filt_t² + Filt_{t−1}² + Filt_{t−2}²) / 3
+/// EBSW   = Wave / sqrt(Pwr)
+/// ```
+///
+/// The price is first highpass-filtered to remove the trend, then SuperSmoothed to
+/// remove noise, leaving the dominant cycle. Dividing a 3-bar average of that
+/// cycle by its RMS power normalises the amplitude, so the output reads like a
+/// clean sine wave bounded in `[−1, +1]` whatever the instrument. Unlike the
+/// classic [`SineWave`](crate::SineWave) (which derives in-phase/quadrature
+/// components from the Hilbert transform and can whip in trends), the EBSW stays
+/// well-behaved and is read directly: crossing up through `0`/`−0.9` is a buy
+/// cue, crossing down through `0`/`+0.9` a sell cue.
+///
+/// The first value lands once three SuperSmoothed samples exist
+/// (`warmup_period == 3`). Each `update` is O(1).
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Indicator, EvenBetterSinewave};
+///
+/// let mut indicator = EvenBetterSinewave::new(40, 10).unwrap();
+/// let mut last = None;
+/// for i in 0..120 {
+///     last = indicator.update(100.0 + (f64::from(i) * 0.3).sin() * 5.0);
+/// }
+/// assert!(last.is_some());
+/// ```
+#[derive(Debug, Clone)]
+pub struct EvenBetterSinewave {
+    hp_period: usize,
+    ssf_length: usize,
+    alpha1: f64,
+    smoother: SuperSmoother,
+    prev_price: Option<f64>,
+    hp: f64,
+    filt1: Option<f64>,
+    filt2: Option<f64>,
+    filt3: Option<f64>,
+    last: Option<f64>,
+}
+
+impl EvenBetterSinewave {
+    /// Construct an EBSW with the given highpass `hp_period` and SuperSmoother
+    /// `ssf_length`.
+    ///
+    /// # Errors
+    ///
+    /// Returns [`Error::PeriodZero`] if either argument is `0`.
+    pub fn new(hp_period: usize, ssf_length: usize) -> Result<Self> {
+        if hp_period == 0 || ssf_length == 0 {
+            return Err(Error::PeriodZero);
+        }
+        let w = 2.0 * PI / hp_period as f64;
+        let alpha1 = (1.0 - w.sin()) / w.cos();
+        Ok(Self {
+            hp_period,
+            ssf_length,
+            alpha1,
+            smoother: SuperSmoother::new(ssf_length)?,
+            prev_price: None,
+            hp: 0.0,
+            filt1: None,
+            filt2: None,
+            filt3: None,
+            last: None,
+        })
+    }
+
+    /// Configured `(hp_period, ssf_length)`.
+    pub const fn params(&self) -> (usize, usize) {
+        (self.hp_period, self.ssf_length)
+    }
+
+    /// Current value if available.
+    pub const fn value(&self) -> Option<f64> {
+        self.last
+    }
+}
+
+impl Indicator for EvenBetterSinewave {
+    type Input = f64;
+    type Output = f64;
+
+    fn update(&mut self, price: f64) -> Option<f64> {
+        if !price.is_finite() {
+            return self.last;
+        }
+        let hp = match self.prev_price {
+            Some(prev) => 0.5 * (1.0 + self.alpha1) * (price - prev) + self.alpha1 * self.hp,
+            None => 0.0,
+        };
+        self.prev_price = Some(price);
+        self.hp = hp;
+        let filt = self.smoother.update(hp)?;
+        // Shift the three-deep filter buffer.
+        self.filt3 = self.filt2;
+        self.filt2 = self.filt1;
+        self.filt1 = Some(filt);
+        let (Some(f1), Some(f2), Some(f3)) = (self.filt1, self.filt2, self.filt3) else {
+            return None;
+        };
+        let wave = (f1 + f2 + f3) / 3.0;
+        let pwr = (f1 * f1 + f2 * f2 + f3 * f3) / 3.0;
+        let ebsw = if pwr > 0.0 {
+            (wave / pwr.sqrt()).clamp(-1.0, 1.0)
+        } else {
+            0.0
+        };
+        self.last = Some(ebsw);
+        Some(ebsw)
+    }
+
+    fn reset(&mut self) {
+        self.smoother.reset();
+        self.prev_price = None;
+        self.hp = 0.0;
+        self.filt1 = None;
+        self.filt2 = None;
+        self.filt3 = None;
+        self.last = None;
+    }
+
+    fn warmup_period(&self) -> usize {
+        3
+    }
+
+    fn is_ready(&self) -> bool {
+        self.last.is_some()
+    }
+
+    fn name(&self) -> &'static str {
+        "EvenBetterSinewave"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+
+    #[test]
+    fn rejects_zero_params() {
+        assert!(matches!(
+            EvenBetterSinewave::new(0, 10),
+            Err(Error::PeriodZero)
+        ));
+        assert!(matches!(
+            EvenBetterSinewave::new(40, 0),
+            Err(Error::PeriodZero)
+        ));
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let e = EvenBetterSinewave::new(40, 10).unwrap();
+        assert_eq!(e.params(), (40, 10));
+        assert_eq!(e.warmup_period(), 3);
+        assert_eq!(e.name(), "EvenBetterSinewave");
+        assert!(!e.is_ready());
+        assert_eq!(e.value(), None);
+    }
+
+    #[test]
+    fn first_emission_at_warmup_period() {
+        let mut e = EvenBetterSinewave::new(40, 10).unwrap();
+        let xs: Vec<f64> = (0..12)
+            .map(|i| 100.0 + (f64::from(i) * 0.5).sin() * 3.0)
+            .collect();
+        let out = e.batch(&xs);
+        for v in out.iter().take(2) {
+            assert!(v.is_none());
+        }
+        assert!(out[2].is_some());
+    }
+
+    #[test]
+    fn output_in_range() {
+        let mut e = EvenBetterSinewave::new(40, 10).unwrap();
+        let xs: Vec<f64> = (0..400)
+            .map(|i| 100.0 + (std::f64::consts::TAU * f64::from(i) / 30.0).sin() * 5.0)
+            .collect();
+        for v in e.batch(&xs).into_iter().flatten() {
+            assert!((-1.0..=1.0).contains(&v), "EBSW out of range: {v}");
+        }
+    }
+
+    #[test]
+    fn cyclic_input_swings_both_signs() {
+        let mut e = EvenBetterSinewave::new(30, 8).unwrap();
+        let xs: Vec<f64> = (0..400)
+            .map(|i| 100.0 + (std::f64::consts::TAU * f64::from(i) / 30.0).sin() * 5.0)
+            .collect();
+        let out: Vec<f64> = e.batch(&xs).into_iter().flatten().skip(100).collect();
+        assert!(out.iter().any(|&v| v > 0.5));
+        assert!(out.iter().any(|&v| v < -0.5));
+    }
+
+    #[test]
+    fn ignores_non_finite() {
+        let mut e = EvenBetterSinewave::new(40, 10).unwrap();
+        e.batch(
+            &(0..40)
+                .map(|i| 100.0 + (f64::from(i) * 0.3).sin())
+                .collect::<Vec<_>>(),
+        );
+        let before = e.value();
+        assert_eq!(e.update(f64::NAN), before);
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut e = EvenBetterSinewave::new(40, 10).unwrap();
+        e.batch(
+            &(0..40)
+                .map(|i| 100.0 + (f64::from(i) * 0.3).sin())
+                .collect::<Vec<_>>(),
+        );
+        assert!(e.is_ready());
+        e.reset();
+        assert!(!e.is_ready());
+        assert_eq!(e.value(), None);
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let xs: Vec<f64> = (0..120)
+            .map(|i| 100.0 + (f64::from(i) * 0.25).sin() * 9.0)
+            .collect();
+        let batch = EvenBetterSinewave::new(40, 10).unwrap().batch(&xs);
+        let mut b = EvenBetterSinewave::new(40, 10).unwrap();
+        let streamed: Vec<_> = xs.iter().map(|x| b.update(*x)).collect();
+        assert_eq!(batch, streamed);
+    }
+
+    #[test]
+    fn flat_input_yields_zero_power() {
+        // A constant series drives the highpass/smoother outputs to zero, so the
+        // signal power is zero and the oscillator reports 0.0 (the `pwr == 0` arm).
+        let flat = [100.0_f64; 200];
+        let last = EvenBetterSinewave::new(40, 10)
+            .unwrap()
+            .batch(&flat)
+            .into_iter()
+            .flatten()
+            .last()
+            .unwrap();
+        assert_eq!(last, 0.0);
+    }
+}
@@ -0,0 +1,264 @@
+//! EWMA Volatility — `RiskMetrics` exponentially-weighted volatility.
+
+use crate::error::{Error, Result};
+use crate::traits::Indicator;
+
+/// EWMA Volatility — the `RiskMetrics` exponentially-weighted estimate of the
+/// volatility of log returns.
+///
+/// ```text
+/// r_t  = ln(price_t / price_{t−1})
+/// σ²_t = λ · σ²_{t−1} + (1 − λ) · r²_t
+/// EWMA = √σ²_t
+/// ```
+///
+/// Unlike [`HistoricalVolatility`](crate::HistoricalVolatility) — an equally
+/// weighted, mean-centred sample standard deviation over a fixed window — the
+/// EWMA estimator weights recent squared returns geometrically by the decay
+/// factor `λ`. The most recent return carries weight `1 − λ`, the one before it
+/// `λ(1 − λ)`, and so on, so the estimate reacts to a volatility shock
+/// immediately and then forgets it at rate `λ`. This is the J.P. Morgan
+/// `RiskMetrics` one-parameter model; the standard daily decay is `λ = 0.94`
+/// (monthly `0.97`). No mean is subtracted: squared returns *are* the variance
+/// contribution, which matches the `RiskMetrics` assumption of a zero conditional
+/// mean over short horizons.
+///
+/// The recursion is seeded with the first squared return (`σ²₁ = r²₁`) and emits
+/// from the first return onward, so the very first reading is a one-observation
+/// estimate that the decay then refines. Each `update` is O(1).
+///
+/// Non-finite and non-positive prices are ignored (the log return would be
+/// undefined): the tick is dropped, state is left untouched, and the last value
+/// is returned.
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{EwmaVolatility, Indicator};
+///
+/// let mut indicator = EwmaVolatility::new(0.94).unwrap();
+/// let mut last = None;
+/// for i in 0..80 {
+///     last = indicator.update(100.0 + (f64::from(i) * 0.3).sin() * 5.0);
+/// }
+/// assert!(last.is_some());
+/// ```
+#[derive(Debug, Clone)]
+pub struct EwmaVolatility {
+    lambda: f64,
+    prev_price: Option<f64>,
+    /// Exponentially-weighted variance of log returns; `None` until seeded.
+    variance: Option<f64>,
+    last: Option<f64>,
+}
+
+impl EwmaVolatility {
+    /// Construct a new EWMA-volatility indicator.
+    ///
+    /// `lambda` is the decay factor, strictly between `0` and `1` (`RiskMetrics`
+    /// uses `0.94` for daily data). Larger `lambda` means a longer memory and a
+    /// smoother estimate.
+    ///
+    /// # Errors
+    /// Returns [`Error::InvalidParameter`] if `lambda` is not finite or not in
+    /// the open interval `(0, 1)`.
+    pub fn new(lambda: f64) -> Result<Self> {
+        if !lambda.is_finite() || lambda <= 0.0 || lambda >= 1.0 {
+            return Err(Error::InvalidParameter {
+                message: "EWMA volatility lambda must be in the open interval (0, 1)",
+            });
+        }
+        Ok(Self {
+            lambda,
+            prev_price: None,
+            variance: None,
+            last: None,
+        })
+    }
+
+    /// Configured decay factor.
+    pub const fn lambda(&self) -> f64 {
+        self.lambda
+    }
+
+    /// Current value if available.
+    pub const fn value(&self) -> Option<f64> {
+        self.last
+    }
+}
+
+impl Indicator for EwmaVolatility {
+    type Input = f64;
+    type Output = f64;
+
+    fn update(&mut self, input: f64) -> Option<f64> {
+        // Non-finite / non-positive prices are skipped: `ln(input / prev)` is
+        // undefined, so the tick must not enter the variance recursion.
+        if !input.is_finite() || input <= 0.0 {
+            return self.last;
+        }
+        let Some(prev) = self.prev_price else {
+            self.prev_price = Some(input);
+            return None;
+        };
+        self.prev_price = Some(input);
+        // `prev` came from `self.prev_price`, gated by the guard above, so it is
+        // finite and positive — the log return is always well-defined.
+        let r = (input / prev).ln();
+        let var = match self.variance {
+            // Seed the recursion with the first squared return.
+            None => r * r,
+            Some(prev_var) => self.lambda * prev_var + (1.0 - self.lambda) * r * r,
+        };
+        self.variance = Some(var);
+        // `var` is a convex combination of non-negative terms, but rounding can
+        // leave a tiny negative residual when every return is ~0; clamp first.
+        let vol = var.max(0.0).sqrt();
+        self.last = Some(vol);
+        Some(vol)
+    }
+
+    fn reset(&mut self) {
+        self.prev_price = None;
+        self.variance = None;
+        self.last = None;
+    }
+
+    fn warmup_period(&self) -> usize {
+        // The first log return needs a previous price; the estimate is seeded
+        // and emitted on that first return.
+        2
+    }
+
+    fn is_ready(&self) -> bool {
+        self.last.is_some()
+    }
+
+    fn name(&self) -> &'static str {
+        "EwmaVolatility"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    #[test]
+    fn rejects_invalid_lambda() {
+        for bad in [0.0, 1.0, -0.5, 1.5, f64::NAN, f64::INFINITY] {
+            assert!(matches!(
+                EwmaVolatility::new(bad),
+                Err(Error::InvalidParameter { .. })
+            ));
+        }
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let ewma = EwmaVolatility::new(0.94).unwrap();
+        assert_relative_eq!(ewma.lambda(), 0.94);
+        assert_eq!(ewma.warmup_period(), 2);
+        assert_eq!(ewma.name(), "EwmaVolatility");
+        assert!(!ewma.is_ready());
+        assert_eq!(ewma.value(), None);
+    }
+
+    #[test]
+    fn first_emission_at_warmup_period() {
+        let mut ewma = EwmaVolatility::new(0.94).unwrap();
+        assert_eq!(ewma.update(100.0), None);
+        let out = ewma.update(110.0);
+        assert!(out.is_some());
+        assert!(ewma.is_ready());
+    }
+
+    #[test]
+    fn known_value() {
+        // r1 = ln(110/100), r2 = ln(99/110). Seed σ²₁ = r1²; then
+        // σ²₂ = λ·r1² + (1−λ)·r2².
+        let lambda = 0.94;
+        let mut ewma = EwmaVolatility::new(lambda).unwrap();
+        let out = ewma.batch(&[100.0, 110.0, 99.0]);
+        let r1 = (110.0_f64 / 100.0).ln();
+        let r2 = (99.0_f64 / 110.0).ln();
+        assert_relative_eq!(out[1].unwrap(), r1.abs(), epsilon = 1e-12);
+        let var2 = lambda * r1 * r1 + (1.0 - lambda) * r2 * r2;
+        assert_relative_eq!(out[2].unwrap(), var2.sqrt(), epsilon = 1e-12);
+    }
+
+    #[test]
+    fn constant_series_yields_zero() {
+        let mut ewma = EwmaVolatility::new(0.9).unwrap();
+        for v in ewma.batch(&[100.0; 40]).into_iter().flatten() {
+            assert_relative_eq!(v, 0.0, epsilon = 1e-12);
+        }
+    }
+
+    #[test]
+    fn output_is_non_negative() {
+        let mut ewma = EwmaVolatility::new(0.94).unwrap();
+        let prices: Vec<f64> = (1..=200)
+            .map(|i| 100.0 + (f64::from(i) * 0.3).sin() * 12.0)
+            .collect();
+        for v in ewma.batch(&prices).into_iter().flatten() {
+            assert!(v >= 0.0, "EWMA volatility must be non-negative, got {v}");
+        }
+    }
+
+    #[test]
+    fn ignores_non_finite_input() {
+        let mut ewma = EwmaVolatility::new(0.94).unwrap();
+        let out = ewma.batch(&(1..=20).map(f64::from).collect::<Vec<_>>());
+        let last = *out.last().unwrap();
+        assert!(last.is_some());
+        assert_eq!(ewma.update(f64::NAN), last);
+        assert_eq!(ewma.update(f64::INFINITY), last);
+    }
+
+    #[test]
+    fn skips_non_positive_prices() {
+        let mut ewma = EwmaVolatility::new(0.94).unwrap();
+        let warmup = ewma.batch(&(1..=20).map(f64::from).collect::<Vec<_>>());
+        let baseline = warmup.last().copied().flatten().expect("warmed up");
+        assert_eq!(ewma.update(-5.0), Some(baseline));
+        assert_eq!(ewma.update(0.0), Some(baseline));
+        // State untouched: a clone advanced by the same real tick agrees.
+        let mut control = ewma.clone();
+        let after = ewma.update(21.0).expect("ready");
+        assert_eq!(control.update(21.0).expect("ready"), after);
+    }
+
+    #[test]
+    fn skips_non_positive_before_first_price() {
+        // The skip guard fires before any previous price exists.
+        let mut ewma = EwmaVolatility::new(0.94).unwrap();
+        assert_eq!(ewma.update(0.0), None);
+        assert_eq!(ewma.update(f64::NAN), None);
+        assert_eq!(ewma.update(100.0), None);
+        assert!(ewma.update(110.0).is_some());
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut ewma = EwmaVolatility::new(0.94).unwrap();
+        ewma.batch(&(1..=20).map(f64::from).collect::<Vec<_>>());
+        assert!(ewma.is_ready());
+        ewma.reset();
+        assert!(!ewma.is_ready());
+        assert_eq!(ewma.value(), None);
+        assert_eq!(ewma.update(1.0), None);
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let prices: Vec<f64> = (1..=120)
+            .map(|i| 100.0 + (f64::from(i) * 0.25).sin() * 9.0)
+            .collect();
+        let batch = EwmaVolatility::new(0.94).unwrap().batch(&prices);
+        let mut b = EwmaVolatility::new(0.94).unwrap();
+        let streamed: Vec<_> = prices.iter().map(|p| b.update(*p)).collect();
+        assert_eq!(batch, streamed);
+    }
+}
@@ -0,0 +1,208 @@
+//! Expectancy — expected return per unit of average loss (R-multiple).
+
+use std::collections::VecDeque;
+
+use crate::error::{Error, Result};
+use crate::traits::Indicator;
+
+/// Expectancy — the expected return per trade expressed in units of average
+/// loss (the "R-multiple" expectancy) over the last `period` returns.
+///
+/// ```text
+/// mean    = average of the `period` returns
+/// avgLoss = average of the absolute losing returns (rᵢ < 0)
+/// E       = mean / avgLoss          (0 when there are no losing returns)
+/// ```
+///
+/// Feed a stream of per-trade or per-bar returns. Expectancy answers "how much
+/// do I make per trade for every unit I typically risk": `E = 0.3` means the
+/// system nets `0.3R` per trade on average, where `R` is the average loss.
+/// Dividing the mean return by the average loss makes the figure comparable
+/// across systems with different bet sizes — unlike the raw mean return (which
+/// is just an SMA of the series). A positive `E` is a profitable edge, a
+/// negative `E` a losing one.
+///
+/// When the window contains **no** losing returns there is no risk reference to
+/// normalise against, so the indicator returns `0` (undefined R-multiple)
+/// rather than dividing by zero.
+///
+/// Each `update` is O(1): the running sum and the loss aggregates are
+/// maintained incrementally.
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{BatchExt, Indicator, Expectancy};
+///
+/// let mut indicator = Expectancy::new(4).unwrap();
+/// // returns +2, -1, +2, -1: mean 0.5, avg loss 1 -> E = 0.5.
+/// let out = indicator.batch(&[2.0, -1.0, 2.0, -1.0]);
+/// assert_eq!(out[3], Some(0.5));
+/// ```
+#[derive(Debug, Clone)]
+pub struct Expectancy {
+    period: usize,
+    window: VecDeque<f64>,
+    sum: f64,
+    sum_abs_loss: f64,
+    loss_count: usize,
+}
+
+impl Expectancy {
+    /// Construct a new Expectancy over the given window.
+    ///
+    /// # Errors
+    /// Returns [`Error::PeriodZero`] if `period == 0`.
+    pub fn new(period: usize) -> Result<Self> {
+        if period == 0 {
+            return Err(Error::PeriodZero);
+        }
+        Ok(Self {
+            period,
+            window: VecDeque::with_capacity(period),
+            sum: 0.0,
+            sum_abs_loss: 0.0,
+            loss_count: 0,
+        })
+    }
+
+    /// Configured period.
+    pub const fn period(&self) -> usize {
+        self.period
+    }
+}
+
+impl Indicator for Expectancy {
+    type Input = f64;
+    type Output = f64;
+
+    fn update(&mut self, ret: f64) -> Option<f64> {
+        if self.window.len() == self.period {
+            let old = self.window.pop_front().expect("window is non-empty");
+            self.sum -= old;
+            if old < 0.0 {
+                self.sum_abs_loss -= -old;
+                self.loss_count -= 1;
+            }
+        }
+        self.window.push_back(ret);
+        self.sum += ret;
+        if ret < 0.0 {
+            self.sum_abs_loss += -ret;
+            self.loss_count += 1;
+        }
+        if self.window.len() < self.period {
+            return None;
+        }
+        if self.loss_count == 0 {
+            // No losing returns: no risk reference to express the edge in.
+            return Some(0.0);
+        }
+        let mean = self.sum / self.period as f64;
+        let avg_loss = self.sum_abs_loss / self.loss_count as f64;
+        Some(mean / avg_loss)
+    }
+
+    fn reset(&mut self) {
+        self.window.clear();
+        self.sum = 0.0;
+        self.sum_abs_loss = 0.0;
+        self.loss_count = 0;
+    }
+
+    fn warmup_period(&self) -> usize {
+        self.period
+    }
+
+    fn is_ready(&self) -> bool {
+        self.window.len() == self.period
+    }
+
+    fn name(&self) -> &'static str {
+        "Expectancy"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    #[test]
+    fn rejects_zero_period() {
+        assert!(matches!(Expectancy::new(0), Err(Error::PeriodZero)));
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let e = Expectancy::new(20).unwrap();
+        assert_eq!(e.period(), 20);
+        assert_eq!(e.warmup_period(), 20);
+        assert_eq!(e.name(), "Expectancy");
+        assert!(!e.is_ready());
+    }
+
+    #[test]
+    fn positive_edge() {
+        // +2, -1, +2, -1: mean 0.5, avgLoss 1 -> 0.5.
+        let mut e = Expectancy::new(4).unwrap();
+        let out = e.batch(&[2.0, -1.0, 2.0, -1.0]);
+        assert_relative_eq!(out[3].unwrap(), 0.5, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn negative_edge() {
+        // +1, -2, +1, -2: mean -0.5, avgLoss 2 -> -0.25.
+        let mut e = Expectancy::new(4).unwrap();
+        let out = e.batch(&[1.0, -2.0, 1.0, -2.0]);
+        assert_relative_eq!(out[3].unwrap(), -0.25, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn no_losses_returns_zero() {
+        // All winning returns: no risk reference -> 0.
+        let mut e = Expectancy::new(5).unwrap();
+        for v in e.batch(&[1.0, 2.0, 3.0, 1.0, 2.0]).into_iter().flatten() {
+            assert_relative_eq!(v, 0.0, epsilon = 1e-12);
+        }
+    }
+
+    #[test]
+    fn flat_returns_are_not_losses() {
+        // Zeros are not losses: mean (2+0+2+0)/4 = 1, but no losing returns
+        // -> 0 (undefined R-multiple).
+        let mut e = Expectancy::new(4).unwrap();
+        let out = e.batch(&[2.0, 0.0, 2.0, 0.0]);
+        assert_relative_eq!(out[3].unwrap(), 0.0, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn rolling_window_evicts_old_losses() {
+        // period 4. Window [+2,-1,+2,-1] -> 0.5; then push +3,+3,+3,+3 to evict
+        // all losses -> no losses -> 0.
+        let mut e = Expectancy::new(4).unwrap();
+        let out = e.batch(&[2.0, -1.0, 2.0, -1.0, 3.0, 3.0, 3.0, 3.0]);
+        assert_relative_eq!(out[3].unwrap(), 0.5, epsilon = 1e-12);
+        assert_relative_eq!(out[7].unwrap(), 0.0, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut e = Expectancy::new(5).unwrap();
+        e.batch(&[1.0, -1.0, 2.0, -2.0, 1.0]);
+        assert!(e.is_ready());
+        e.reset();
+        assert!(!e.is_ready());
+        assert_eq!(e.update(1.0), None);
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let rets: Vec<f64> = (0..60).map(|i| (f64::from(i) * 0.5).sin() * 2.0).collect();
+        let batch = Expectancy::new(14).unwrap().batch(&rets);
+        let mut b = Expectancy::new(14).unwrap();
+        let streamed: Vec<_> = rets.iter().map(|p| b.update(*p)).collect();
+        assert_eq!(batch, streamed);
+    }
+}
@@ -0,0 +1,186 @@
+//! Fisher-transformed RSI.
+
+use crate::error::Result;
+use crate::indicators::rsi::Rsi;
+use crate::traits::Indicator;
+
+/// Fisher RSI — the Fisher transform applied to a normalised [`Rsi`](crate::Rsi).
+///
+/// The RSI is bounded in `[0, 100]` and its distribution piles up near the
+/// middle, which blurs turning points. The Fisher transform reshapes a bounded
+/// input toward a Gaussian, sharpening the extremes into clear, near-symmetric
+/// peaks:
+///
+/// ```text
+/// rsi   = RSI(price, period)            in [0, 100]
+/// x     = clamp((rsi - 50) / 50, ±0.999)   normalise to (-1, 1)
+/// Fisher = 0.5 * ln((1 + x) / (1 - x))
+/// ```
+///
+/// The clamp keeps the logarithm finite when the RSI pins at `0` or `100`. The
+/// output is unbounded but in practice oscillates in roughly `[-3, 3]`, with
+/// sharp excursions marking momentum extremes. The first value lands with the
+/// inner RSI, after `period + 1` inputs.
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{FisherRsi, Indicator};
+///
+/// let mut indicator = FisherRsi::new(9).unwrap();
+/// let mut last = None;
+/// for i in 0..80 {
+///     last = indicator.update(100.0 + (f64::from(i) * 0.3).sin() * 5.0);
+/// }
+/// assert!(last.is_some());
+/// ```
+#[derive(Debug, Clone)]
+pub struct FisherRsi {
+    period: usize,
+    rsi: Rsi,
+}
+
+impl FisherRsi {
+    /// Construct a Fisher RSI with the given RSI period.
+    ///
+    /// # Errors
+    ///
+    /// Returns [`crate::Error::PeriodZero`] if `period == 0`.
+    pub fn new(period: usize) -> Result<Self> {
+        Ok(Self {
+            period,
+            rsi: Rsi::new(period)?,
+        })
+    }
+
+    /// Configured period.
+    pub const fn period(&self) -> usize {
+        self.period
+    }
+}
+
+impl Indicator for FisherRsi {
+    type Input = f64;
+    type Output = f64;
+
+    fn update(&mut self, input: f64) -> Option<f64> {
+        let rsi = self.rsi.update(input)?;
+        let x = ((rsi - 50.0) / 50.0).clamp(-0.999, 0.999);
+        Some(0.5 * ((1.0 + x) / (1.0 - x)).ln())
+    }
+
+    fn reset(&mut self) {
+        self.rsi.reset();
+    }
+
+    fn warmup_period(&self) -> usize {
+        self.rsi.warmup_period()
+    }
+
+    fn is_ready(&self) -> bool {
+        self.rsi.is_ready()
+    }
+
+    fn name(&self) -> &'static str {
+        "FisherRSI"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    #[test]
+    fn rejects_zero_period() {
+        assert!(FisherRsi::new(0).is_err());
+    }
+
+    /// Cover the const accessor `period` and the Indicator-impl `warmup_period`
+    /// + `name`.
+    #[test]
+    fn accessors_and_metadata() {
+        let f = FisherRsi::new(9).unwrap();
+        assert_eq!(f.period(), 9);
+        // RSI warmup is period + 1.
+        assert_eq!(f.warmup_period(), 10);
+        assert_eq!(f.name(), "FisherRSI");
+    }
+
+    #[test]
+    fn warmup_matches_rsi() {
+        let mut f = FisherRsi::new(3).unwrap();
+        // RSI(3) needs 4 inputs; the first three return None.
+        assert_eq!(f.update(1.0), None);
+        assert_eq!(f.update(2.0), None);
+        assert_eq!(f.update(3.0), None);
+        assert!(f.update(4.0).is_some());
+    }
+
+    #[test]
+    fn matches_fisher_of_rsi() {
+        // Fisher RSI must equal the Fisher transform of the standalone RSI.
+        let prices: Vec<f64> = (0..60)
+            .map(|i| 100.0 + (f64::from(i) * 0.4).sin() * 8.0)
+            .collect();
+        let mut fr = FisherRsi::new(9).unwrap();
+        let mut rsi = Rsi::new(9).unwrap();
+        for (i, &p) in prices.iter().enumerate() {
+            let got = fr.update(p);
+            let want = rsi.update(p).map(|r| {
+                let x = ((r - 50.0) / 50.0).clamp(-0.999, 0.999);
+                0.5 * ((1.0 + x) / (1.0 - x)).ln()
+            });
+            assert_eq!(got.is_some(), want.is_some(), "readiness mismatch at {i}");
+            if let (Some(a), Some(b)) = (got, want) {
+                assert_relative_eq!(a, b, epsilon = 1e-12);
+            }
+        }
+    }
+
+    #[test]
+    fn strong_uptrend_is_positive() {
+        // A pure uptrend pins RSI near 100 -> x near +1 -> large positive Fisher.
+        let prices: Vec<f64> = (1..=40).map(f64::from).collect();
+        let mut f = FisherRsi::new(9).unwrap();
+        let last = f.batch(&prices).into_iter().flatten().last().unwrap();
+        assert!(
+            last > 1.0,
+            "strong uptrend should give a large positive value, got {last}"
+        );
+    }
+
+    #[test]
+    fn clamp_keeps_output_finite_at_extremes() {
+        // Monotonic rise pins RSI at 100; the clamp must keep Fisher finite.
+        let prices: Vec<f64> = (1..=30).map(f64::from).collect();
+        let mut f = FisherRsi::new(5).unwrap();
+        for v in f.batch(&prices).into_iter().flatten() {
+            assert!(v.is_finite(), "Fisher RSI must stay finite, got {v}");
+        }
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut f = FisherRsi::new(5).unwrap();
+        f.batch(&(1..=20).map(f64::from).collect::<Vec<_>>());
+        assert!(f.is_ready());
+        f.reset();
+        assert!(!f.is_ready());
+        assert_eq!(f.update(1.0), None);
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let prices: Vec<f64> = (1..=40)
+            .map(|i| 50.0 + (f64::from(i) * 0.5).sin() * 10.0)
+            .collect();
+        let mut a = FisherRsi::new(9).unwrap();
+        let mut b = FisherRsi::new(9).unwrap();
+        assert_eq!(
+            a.batch(&prices),
+            prices.iter().map(|p| b.update(*p)).collect::<Vec<_>>()
+        );
+    }
+}
@@ -0,0 +1,325 @@
+//! GARCH(1,1) — conditional volatility with a long-run-variance anchor.
+
+use crate::error::{Error, Result};
+use crate::traits::Indicator;
+
+/// GARCH(1,1) conditional volatility — the square root of the
+/// generalized-autoregressive-conditional-heteroskedasticity variance recursion.
+///
+/// ```text
+/// r_t  = ln(price_t / price_{t−1})
+/// σ²_t = ω + α · r²_{t−1} + β · σ²_{t−1}
+/// out  = √σ²_t
+/// ```
+///
+/// GARCH(1,1) (Bollerslev 1986) generalizes the
+/// [`EwmaVolatility`](crate::EwmaVolatility) recursion by adding a constant `ω`,
+/// which pins the process to a finite long-run (unconditional) variance
+/// `ω / (1 − α − β)`. The `α` term gives weight to the latest squared return
+/// (the "ARCH" shock) and `β` to the previous variance (the "GARCH"
+/// persistence). When `ω = 0` and `α + β = 1` the model degenerates to EWMA; a
+/// proper GARCH keeps `ω > 0` and `α + β < 1` so volatility mean-reverts rather
+/// than drifting.
+///
+/// The recursion is seeded with the unconditional variance (`σ²₁ = ω / (1 − α −
+/// β)`) and emits from the first log return onward. Unlike EWMA — which decays to
+/// zero on a flat series — a flat series here mean-reverts toward `ω / (1 − β)`
+/// (the `α`-term vanishes but the `ω` floor and the `β` carry remain), so the
+/// output is always strictly positive. Each `update` is O(1).
+///
+/// Non-finite and non-positive prices are ignored (the log return would be
+/// undefined): the tick is dropped, state is left untouched, and the last value
+/// is returned.
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Garch11, Indicator};
+///
+/// // Typical equity daily estimate.
+/// let mut indicator = Garch11::new(0.000_002, 0.10, 0.88).unwrap();
+/// let mut last = None;
+/// for i in 0..80 {
+///     last = indicator.update(100.0 + (f64::from(i) * 0.3).sin() * 5.0);
+/// }
+/// assert!(last.is_some());
+/// ```
+#[derive(Debug, Clone)]
+pub struct Garch11 {
+    omega: f64,
+    alpha: f64,
+    beta: f64,
+    unconditional: f64,
+    prev_price: Option<f64>,
+    /// `(σ²_{t−1}, r²_{t−1})` — previous variance and previous squared return.
+    state: Option<(f64, f64)>,
+    last: Option<f64>,
+}
+
+impl Garch11 {
+    /// Construct a new GARCH(1,1) indicator from its three parameters.
+    ///
+    /// `omega` (`ω`) is the constant variance floor, `alpha` (`α`) the weight on
+    /// the latest squared return, and `beta` (`β`) the persistence of the
+    /// previous variance.
+    ///
+    /// # Errors
+    /// Returns [`Error::InvalidParameter`] unless every parameter is finite,
+    /// `omega > 0`, `alpha >= 0`, `beta >= 0`, and `alpha + beta < 1` (the
+    /// covariance-stationarity condition that gives a finite long-run variance).
+    pub fn new(omega: f64, alpha: f64, beta: f64) -> Result<Self> {
+        if !omega.is_finite() || !alpha.is_finite() || !beta.is_finite() {
+            return Err(Error::InvalidParameter {
+                message: "GARCH(1,1) parameters must be finite",
+            });
+        }
+        if omega <= 0.0 {
+            return Err(Error::InvalidParameter {
+                message: "GARCH(1,1) omega must be > 0",
+            });
+        }
+        if alpha < 0.0 || beta < 0.0 {
+            return Err(Error::InvalidParameter {
+                message: "GARCH(1,1) alpha and beta must be >= 0",
+            });
+        }
+        if alpha + beta >= 1.0 {
+            return Err(Error::InvalidParameter {
+                message: "GARCH(1,1) requires alpha + beta < 1 (covariance stationarity)",
+            });
+        }
+        Ok(Self {
+            omega,
+            alpha,
+            beta,
+            unconditional: omega / (1.0 - alpha - beta),
+            prev_price: None,
+            state: None,
+            last: None,
+        })
+    }
+
+    /// Configured `(omega, alpha, beta)`.
+    pub const fn params(&self) -> (f64, f64, f64) {
+        (self.omega, self.alpha, self.beta)
+    }
+
+    /// Long-run (unconditional) variance `ω / (1 − α − β)`.
+    pub const fn unconditional_variance(&self) -> f64 {
+        self.unconditional
+    }
+
+    /// Current value if available.
+    pub const fn value(&self) -> Option<f64> {
+        self.last
+    }
+}
+
+impl Indicator for Garch11 {
+    type Input = f64;
+    type Output = f64;
+
+    fn update(&mut self, input: f64) -> Option<f64> {
+        // Non-finite / non-positive prices are skipped: `ln(input / prev)` is
+        // undefined, so the tick must not enter the variance recursion.
+        if !input.is_finite() || input <= 0.0 {
+            return self.last;
+        }
+        let Some(prev) = self.prev_price else {
+            self.prev_price = Some(input);
+            return None;
+        };
+        self.prev_price = Some(input);
+        // `prev` came from `self.prev_price`, gated by the guard above, so it is
+        // finite and positive — the log return is always well-defined.
+        let r = (input / prev).ln();
+        let r_sq = r * r;
+        let var = match self.state {
+            // Seed the recursion with the unconditional variance.
+            None => self.unconditional,
+            Some((prev_var, prev_r_sq)) => {
+                self.omega + self.alpha * prev_r_sq + self.beta * prev_var
+            }
+        };
+        self.state = Some((var, r_sq));
+        // `var` is `omega (> 0) + non-negative terms`, so it is strictly
+        // positive — the square root is always well-defined.
+        let vol = var.sqrt();
+        self.last = Some(vol);
+        Some(vol)
+    }
+
+    fn reset(&mut self) {
+        self.prev_price = None;
+        self.state = None;
+        self.last = None;
+    }
+
+    fn warmup_period(&self) -> usize {
+        // The first log return needs a previous price; the estimate is seeded
+        // with the unconditional variance and emitted on that first return.
+        2
+    }
+
+    fn is_ready(&self) -> bool {
+        self.last.is_some()
+    }
+
+    fn name(&self) -> &'static str {
+        "Garch11"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    #[test]
+    fn rejects_invalid_params() {
+        assert!(matches!(
+            Garch11::new(0.0, 0.1, 0.8),
+            Err(Error::InvalidParameter { .. })
+        ));
+        assert!(matches!(
+            Garch11::new(-1.0, 0.1, 0.8),
+            Err(Error::InvalidParameter { .. })
+        ));
+        assert!(matches!(
+            Garch11::new(0.001, -0.1, 0.8),
+            Err(Error::InvalidParameter { .. })
+        ));
+        assert!(matches!(
+            Garch11::new(0.001, 0.1, -0.8),
+            Err(Error::InvalidParameter { .. })
+        ));
+        assert!(matches!(
+            Garch11::new(0.001, 0.5, 0.5),
+            Err(Error::InvalidParameter { .. })
+        ));
+        assert!(matches!(
+            Garch11::new(f64::NAN, 0.1, 0.8),
+            Err(Error::InvalidParameter { .. })
+        ));
+        assert!(matches!(
+            Garch11::new(0.001, f64::INFINITY, 0.8),
+            Err(Error::InvalidParameter { .. })
+        ));
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let g = Garch11::new(0.001, 0.1, 0.85).unwrap();
+        assert_eq!(g.params(), (0.001, 0.1, 0.85));
+        assert_relative_eq!(g.unconditional_variance(), 0.001 / 0.05, epsilon = 1e-12);
+        assert_eq!(g.warmup_period(), 2);
+        assert_eq!(g.name(), "Garch11");
+        assert!(!g.is_ready());
+        assert_eq!(g.value(), None);
+    }
+
+    #[test]
+    fn first_emission_is_unconditional() {
+        // The first log return emits the seed = sqrt(unconditional variance),
+        // independent of the return value.
+        let g = Garch11::new(0.002, 0.1, 0.85);
+        let mut g = g.unwrap();
+        assert_eq!(g.update(100.0), None);
+        let out = g.update(110.0).unwrap();
+        assert_relative_eq!(out, (0.002_f64 / 0.05).sqrt(), epsilon = 1e-12);
+    }
+
+    #[test]
+    fn known_value() {
+        // σ²₁ = uncond; σ²₂ = ω + α·r1² + β·uncond.
+        let (omega, alpha, beta) = (0.002, 0.1, 0.85);
+        let mut g = Garch11::new(omega, alpha, beta).unwrap();
+        let out = g.batch(&[100.0, 110.0, 99.0]);
+        let uncond = omega / (1.0 - alpha - beta);
+        let r1 = (110.0_f64 / 100.0).ln();
+        assert_relative_eq!(out[1].unwrap(), uncond.sqrt(), epsilon = 1e-12);
+        let var2 = omega + alpha * r1 * r1 + beta * uncond;
+        assert_relative_eq!(out[2].unwrap(), var2.sqrt(), epsilon = 1e-12);
+    }
+
+    #[test]
+    fn flat_series_converges_to_long_run() {
+        // With zero returns the alpha term vanishes; the variance mean-reverts
+        // to the fixed point ω / (1 − β), NOT to zero (the key GARCH/EWMA
+        // distinction).
+        let (omega, beta) = (0.002, 0.85);
+        let mut g = Garch11::new(omega, 0.10, beta).unwrap();
+        let out = g.batch(&[100.0; 400]);
+        let fixed_point = (omega / (1.0 - beta)).sqrt();
+        assert_relative_eq!(out.last().unwrap().unwrap(), fixed_point, epsilon = 1e-9);
+    }
+
+    #[test]
+    fn output_is_strictly_positive() {
+        let mut g = Garch11::new(0.000_002, 0.1, 0.88).unwrap();
+        let prices: Vec<f64> = (1..=200)
+            .map(|i| 100.0 + (f64::from(i) * 0.3).sin() * 12.0)
+            .collect();
+        for v in g.batch(&prices).into_iter().flatten() {
+            assert!(
+                v > 0.0,
+                "GARCH volatility must be strictly positive, got {v}"
+            );
+        }
+    }
+
+    #[test]
+    fn ignores_non_finite_input() {
+        let mut g = Garch11::new(0.001, 0.1, 0.85).unwrap();
+        let out = g.batch(&(1..=20).map(f64::from).collect::<Vec<_>>());
+        let last = *out.last().unwrap();
+        assert!(last.is_some());
+        assert_eq!(g.update(f64::NAN), last);
+        assert_eq!(g.update(f64::INFINITY), last);
+    }
+
+    #[test]
+    fn skips_non_positive_prices() {
+        let mut g = Garch11::new(0.001, 0.1, 0.85).unwrap();
+        let warmup = g.batch(&(1..=20).map(f64::from).collect::<Vec<_>>());
+        let baseline = warmup.last().copied().flatten().expect("warmed up");
+        assert_eq!(g.update(-5.0), Some(baseline));
+        assert_eq!(g.update(0.0), Some(baseline));
+        // State untouched: a clone advanced by the same real tick agrees.
+        let mut control = g.clone();
+        let after = g.update(21.0).expect("ready");
+        assert_eq!(control.update(21.0).expect("ready"), after);
+    }
+
+    #[test]
+    fn skips_non_positive_before_first_price() {
+        let mut g = Garch11::new(0.001, 0.1, 0.85).unwrap();
+        assert_eq!(g.update(0.0), None);
+        assert_eq!(g.update(f64::NAN), None);
+        assert_eq!(g.update(100.0), None);
+        assert!(g.update(110.0).is_some());
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut g = Garch11::new(0.001, 0.1, 0.85).unwrap();
+        g.batch(&(1..=20).map(f64::from).collect::<Vec<_>>());
+        assert!(g.is_ready());
+        g.reset();
+        assert!(!g.is_ready());
+        assert_eq!(g.value(), None);
+        assert_eq!(g.update(1.0), None);
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let prices: Vec<f64> = (1..=120)
+            .map(|i| 100.0 + (f64::from(i) * 0.25).sin() * 9.0)
+            .collect();
+        let batch = Garch11::new(0.000_002, 0.1, 0.88).unwrap().batch(&prices);
+        let mut b = Garch11::new(0.000_002, 0.1, 0.88).unwrap();
+        let streamed: Vec<_> = prices.iter().map(|p| b.update(*p)).collect();
+        assert_eq!(batch, streamed);
+    }
+}
@@ -0,0 +1,205 @@
+//! Bill Williams' Gator Oscillator (derived from the Alligator).
+
+use crate::error::Result;
+use crate::indicators::alligator::Alligator;
+use crate::ohlcv::Candle;
+use crate::traits::Indicator;
+
+/// Gator Oscillator output: the two histogram bars drawn above and below the
+/// zero line.
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub struct GatorOscillatorOutput {
+    /// Upper histogram `|jaw - teeth|`, always `>= 0`.
+    pub upper: f64,
+    /// Lower histogram `-|teeth - lips|`, always `<= 0`.
+    pub lower: f64,
+}
+
+/// Bill Williams' Gator Oscillator: a convergence/divergence view of the
+/// [`Alligator`] lines. The upper bar is the absolute gap between Jaw and
+/// Teeth; the lower bar is the negated absolute gap between Teeth and Lips.
+///
+/// ```text
+/// upper =  |jaw   - teeth|
+/// lower = -|teeth - lips |
+/// ```
+///
+/// Widening bars mean the Alligator's mouth is opening (a trending market);
+/// shrinking bars mean it is closing (consolidation). Warmup matches the
+/// underlying Alligator — the first value appears once the slowest line (Jaw)
+/// has warmed up.
+///
+/// Reference: Bill Williams, *Trading Chaos*, 1995.
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Candle, GatorOscillator, Indicator};
+///
+/// let mut indicator = GatorOscillator::classic();
+/// let mut last = None;
+/// for i in 0..40 {
+///     let base = 100.0 + f64::from(i);
+///     let candle =
+///         Candle::new(base, base + 1.0, base - 1.0, base, 1.0, i64::from(i)).unwrap();
+///     last = indicator.update(candle);
+/// }
+/// assert!(last.is_some());
+/// ```
+#[derive(Debug, Clone)]
+pub struct GatorOscillator {
+    alligator: Alligator,
+}
+
+impl GatorOscillator {
+    /// Construct a Gator Oscillator from explicit Alligator periods
+    /// `(jaw, teeth, lips)`.
+    ///
+    /// # Errors
+    ///
+    /// Returns [`Error::PeriodZero`](crate::error::Error::PeriodZero) if any period is zero.
+    pub fn new(jaw_period: usize, teeth_period: usize, lips_period: usize) -> Result<Self> {
+        Ok(Self {
+            alligator: Alligator::new(jaw_period, teeth_period, lips_period)?,
+        })
+    }
+
+    /// Bill Williams' classic parameters: `(jaw = 13, teeth = 8, lips = 5)`.
+    pub fn classic() -> Self {
+        Self {
+            alligator: Alligator::classic(),
+        }
+    }
+
+    /// Configured `(jaw_period, teeth_period, lips_period)`.
+    pub const fn periods(&self) -> (usize, usize, usize) {
+        self.alligator.periods()
+    }
+}
+
+impl Indicator for GatorOscillator {
+    type Input = Candle;
+    type Output = GatorOscillatorOutput;
+
+    fn update(&mut self, candle: Candle) -> Option<GatorOscillatorOutput> {
+        let lines = self.alligator.update(candle)?;
+        Some(GatorOscillatorOutput {
+            upper: (lines.jaw - lines.teeth).abs(),
+            lower: -(lines.teeth - lines.lips).abs(),
+        })
+    }
+
+    fn reset(&mut self) {
+        self.alligator.reset();
+    }
+
+    fn warmup_period(&self) -> usize {
+        self.alligator.warmup_period()
+    }
+
+    fn is_ready(&self) -> bool {
+        self.alligator.is_ready()
+    }
+
+    fn name(&self) -> &'static str {
+        "GatorOscillator"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::error::Error;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    fn candle(high: f64, low: f64, ts: i64) -> Candle {
+        let close = f64::midpoint(high, low);
+        Candle::new(close, high, low, close, 1.0, ts).unwrap()
+    }
+
+    #[test]
+    fn rejects_zero_period() {
+        assert!(matches!(
+            GatorOscillator::new(0, 8, 5),
+            Err(Error::PeriodZero)
+        ));
+        assert!(matches!(
+            GatorOscillator::new(13, 0, 5),
+            Err(Error::PeriodZero)
+        ));
+        assert!(matches!(
+            GatorOscillator::new(13, 8, 0),
+            Err(Error::PeriodZero)
+        ));
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let g = GatorOscillator::classic();
+        assert_eq!(g.periods(), (13, 8, 5));
+        assert_eq!(g.warmup_period(), 13);
+        assert_eq!(g.name(), "GatorOscillator");
+        assert!(!g.is_ready());
+    }
+
+    #[test]
+    fn constant_series_collapses_both_bars() {
+        // All three Alligator lines equal the constant median -> zero spread.
+        let mut g = GatorOscillator::classic();
+        let candles: Vec<Candle> = (0..40).map(|i| candle(11.0, 9.0, i)).collect();
+        let out = g.batch(&candles);
+        let last = out.last().unwrap().unwrap();
+        assert_relative_eq!(last.upper, 0.0, epsilon = 1e-12);
+        assert_relative_eq!(last.lower, 0.0, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn trending_series_opens_the_mouth() {
+        // On a clean trend the lines separate -> upper > 0, lower < 0.
+        let mut g = GatorOscillator::classic();
+        let candles: Vec<Candle> = (0_i64..80)
+            .map(|i| candle(10.0 + i as f64, 9.0 + i as f64, i))
+            .collect();
+        let last = g.batch(&candles).last().unwrap().unwrap();
+        assert!(last.upper > 0.0, "upper {} should be positive", last.upper);
+        assert!(last.lower < 0.0, "lower {} should be negative", last.lower);
+    }
+
+    #[test]
+    fn warmup_emits_first_value_at_longest_period() {
+        let mut g = GatorOscillator::new(5, 3, 2).unwrap();
+        let candles: Vec<Candle> = (0..6).map(|i| candle(11.0, 9.0, i)).collect();
+        let out = g.batch(&candles);
+        for v in out.iter().take(4) {
+            assert!(v.is_none());
+        }
+        assert!(out[4].is_some());
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut g = GatorOscillator::classic();
+        let candles: Vec<Candle> = (0..40).map(|i| candle(11.0, 9.0, i)).collect();
+        g.batch(&candles);
+        assert!(g.is_ready());
+        g.reset();
+        assert!(!g.is_ready());
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let candles: Vec<Candle> = (0..80_i64)
+            .map(|i| {
+                let base = 100.0 + (i as f64 * 0.2).sin() * 5.0;
+                candle(base + 1.0, base - 1.0, i)
+            })
+            .collect();
+        let mut a = GatorOscillator::classic();
+        let mut b = GatorOscillator::classic();
+        assert_eq!(
+            a.batch(&candles),
+            candles.iter().map(|c| b.update(*c)).collect::<Vec<_>>()
+        );
+    }
+}
@@ -0,0 +1,222 @@
+//! Generalized DEMA (GD) — Tim Tillson's volume-factor double EMA.
+
+use crate::error::{Error, Result};
+use crate::indicators::ema::Ema;
+use crate::traits::Indicator;
+
+/// Generalized DEMA — the building block of Tillson's [`T3`](crate::T3),
+/// exposed on its own.
+///
+/// ```text
+/// GD = (1 + v) · EMA(price) − v · EMA(EMA(price))
+/// ```
+///
+/// where both EMAs share the same `period` and `v ∈ [0, 1]` is the *volume
+/// factor*. `v` controls how much of the second-order lag correction is
+/// applied:
+///
+/// - `v = 0` collapses GD to a plain [`Ema`](crate::Ema) (no correction).
+/// - `v = 1` recovers the standard [`Dema`](crate::Dema) `2·EMA − EMA(EMA)`.
+/// - intermediate values (Tillson uses `0.7`) trade a little lag reduction for
+///   less overshoot than DEMA.
+///
+/// Because the coefficients `(1 + v)` and `−v` always sum to `1`, a constant
+/// series maps to itself. The first output lands after `2·period − 1` inputs —
+/// EMA1 seeds at `period`, then EMA2 needs another `period − 1` of EMA1's
+/// outputs to seed, exactly like DEMA.
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Indicator, GeneralizedDema};
+///
+/// let mut indicator = GeneralizedDema::new(5, 0.7).unwrap();
+/// let mut last = None;
+/// for i in 0..80 {
+///     last = indicator.update(100.0 + f64::from(i));
+/// }
+/// assert!(last.is_some());
+/// ```
+#[derive(Debug, Clone)]
+pub struct GeneralizedDema {
+    ema1: Ema,
+    ema2: Ema,
+    period: usize,
+    v: f64,
+}
+
+impl GeneralizedDema {
+    /// Construct a generalized DEMA with the given `period` and volume factor
+    /// `v`.
+    ///
+    /// # Errors
+    ///
+    /// Returns [`Error::PeriodZero`] if `period == 0`, or
+    /// [`Error::InvalidPeriod`] if `v` is non-finite or outside `[0.0, 1.0]`.
+    pub fn new(period: usize, v: f64) -> Result<Self> {
+        if period == 0 {
+            return Err(Error::PeriodZero);
+        }
+        if !v.is_finite() || !(0.0..=1.0).contains(&v) {
+            return Err(Error::InvalidPeriod {
+                message: "GD volume factor must be a finite value in [0.0, 1.0]",
+            });
+        }
+        Ok(Self {
+            ema1: Ema::new(period)?,
+            ema2: Ema::new(period)?,
+            period,
+            v,
+        })
+    }
+
+    /// Configured period.
+    pub const fn period(&self) -> usize {
+        self.period
+    }
+
+    /// Configured volume factor `v`.
+    pub const fn volume_factor(&self) -> f64 {
+        self.v
+    }
+}
+
+impl Indicator for GeneralizedDema {
+    type Input = f64;
+    type Output = f64;
+
+    fn update(&mut self, input: f64) -> Option<f64> {
+        let e1 = self.ema1.update(input)?;
+        let e2 = self.ema2.update(e1)?;
+        Some((1.0 + self.v) * e1 - self.v * e2)
+    }
+
+    fn reset(&mut self) {
+        self.ema1.reset();
+        self.ema2.reset();
+    }
+
+    fn warmup_period(&self) -> usize {
+        // EMA1 seeds at period, then EMA2 needs another (period - 1) values.
+        2 * self.period - 1
+    }
+
+    fn is_ready(&self) -> bool {
+        self.ema2.is_ready()
+    }
+
+    fn name(&self) -> &'static str {
+        "GD"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::indicators::Dema;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    #[test]
+    fn rejects_zero_period() {
+        assert!(matches!(
+            GeneralizedDema::new(0, 0.7),
+            Err(Error::PeriodZero)
+        ));
+    }
+
+    #[test]
+    fn rejects_invalid_volume_factor() {
+        assert!(matches!(
+            GeneralizedDema::new(5, -0.1),
+            Err(Error::InvalidPeriod { .. })
+        ));
+        assert!(matches!(
+            GeneralizedDema::new(5, 1.5),
+            Err(Error::InvalidPeriod { .. })
+        ));
+        assert!(matches!(
+            GeneralizedDema::new(5, f64::NAN),
+            Err(Error::InvalidPeriod { .. })
+        ));
+        assert!(GeneralizedDema::new(5, 0.0).is_ok());
+        assert!(GeneralizedDema::new(5, 1.0).is_ok());
+    }
+
+    /// Cover the const accessors `period` + `volume_factor` and the
+    /// Indicator-impl `warmup_period` + `name`.
+    #[test]
+    fn accessors_and_metadata() {
+        let gd = GeneralizedDema::new(5, 0.7).unwrap();
+        assert_eq!(gd.period(), 5);
+        assert_relative_eq!(gd.volume_factor(), 0.7, epsilon = 1e-12);
+        // EMA1 seeds at 5, EMA2 needs another 4 -> 2*period - 1 = 9.
+        assert_eq!(gd.warmup_period(), 9);
+        assert_eq!(gd.name(), "GD");
+    }
+
+    #[test]
+    fn constant_series_yields_constant() {
+        let mut gd = GeneralizedDema::new(5, 0.7).unwrap();
+        let out = gd.batch(&[100.0_f64; 60]);
+        let last = out.iter().rev().flatten().next().unwrap();
+        assert_relative_eq!(*last, 100.0, epsilon = 1e-9);
+    }
+
+    #[test]
+    fn v_one_equals_dema() {
+        // GD with v = 1 is exactly the standard DEMA.
+        let prices: Vec<f64> = (1..=80)
+            .map(|i| (f64::from(i) * 0.3).sin() * 10.0 + 50.0)
+            .collect();
+        let mut gd = GeneralizedDema::new(7, 1.0).unwrap();
+        let mut dema = Dema::new(7).unwrap();
+        let gd_out = gd.batch(&prices);
+        let dema_out = dema.batch(&prices);
+        for (g, d) in gd_out.iter().zip(dema_out.iter()) {
+            assert_eq!(g.is_some(), d.is_some());
+            if let (Some(a), Some(b)) = (g, d) {
+                assert_relative_eq!(*a, *b, epsilon = 1e-9);
+            }
+        }
+    }
+
+    #[test]
+    fn v_zero_equals_ema() {
+        // GD with v = 0 is a plain EMA (no second-order correction).
+        let prices: Vec<f64> = (1..=60).map(|i| f64::from(i) * 0.5).collect();
+        let mut gd = GeneralizedDema::new(6, 0.0).unwrap();
+        let mut ema = Ema::new(6).unwrap();
+        let gd_out = gd.batch(&prices);
+        for (i, (g, p)) in gd_out.iter().zip(prices.iter()).enumerate() {
+            // GD(v=0) feeds EMA1 into EMA2 but outputs EMA1 alone (coefficient
+            // 1 on e1, 0 on e2); it is only ready once EMA2 is, so compare
+            // against a standalone EMA chained the same way.
+            let want = ema.update(*p).filter(|_| i + 1 >= gd.warmup_period());
+            if let (Some(a), Some(b)) = (g, want) {
+                assert_relative_eq!(*a, b, epsilon = 1e-9);
+            }
+        }
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let prices: Vec<f64> = (1..=80).map(|i| f64::from(i) * 0.5).collect();
+        let mut a = GeneralizedDema::new(7, 0.7).unwrap();
+        let mut b = GeneralizedDema::new(7, 0.7).unwrap();
+        assert_eq!(
+            a.batch(&prices),
+            prices.iter().map(|p| b.update(*p)).collect::<Vec<_>>()
+        );
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut gd = GeneralizedDema::new(5, 0.7).unwrap();
+        gd.batch(&(1..=50).map(f64::from).collect::<Vec<_>>());
+        assert!(gd.is_ready());
+        gd.reset();
+        assert!(!gd.is_ready());
+        assert_eq!(gd.update(1.0), None);
+    }
+}
@@ -0,0 +1,275 @@
+//! Geometric Moving Average (GMA).
+
+use std::collections::VecDeque;
+
+use crate::error::{Error, Result};
+use crate::traits::Indicator;
+
+/// Geometric Moving Average — the rolling geometric mean of the last `period`
+/// inputs.
+///
+/// ```text
+/// GMA = (Π value_i)^(1/period) = exp( (1/period) · Σ ln(value_i) )
+/// ```
+///
+/// The geometric mean is the natural average for *multiplicative* quantities
+/// such as prices and growth factors: averaging in log-space weights relative
+/// (percentage) moves symmetrically, so a `+10%` followed by a `−10%` move
+/// pulls the average below the start, exactly as compounded returns do. It is
+/// always less than or equal to the arithmetic mean of the same window.
+///
+/// Maintained incrementally in O(1): the running sum of natural logs is updated
+/// by adding the newcomer's log and subtracting the departing value's log as
+/// the window slides.
+///
+/// The geometric mean is only defined for **strictly positive** inputs. A
+/// non-finite or non-positive input is ignored (it leaves the window unchanged
+/// and returns the current value), mirroring the non-finite handling of the
+/// other moving averages.
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Indicator, GeometricMa};
+///
+/// let mut indicator = GeometricMa::new(5).unwrap();
+/// let mut last = None;
+/// for i in 0..80 {
+///     last = indicator.update(100.0 + f64::from(i));
+/// }
+/// assert!(last.is_some());
+/// ```
+#[derive(Debug, Clone)]
+pub struct GeometricMa {
+    period: usize,
+    /// Natural logs of the values currently in the window (oldest at front).
+    logs: VecDeque<f64>,
+    sum_logs: f64,
+}
+
+impl GeometricMa {
+    /// Construct a new geometric moving average over `period` inputs.
+    ///
+    /// # Errors
+    ///
+    /// Returns [`Error::PeriodZero`] if `period == 0`.
+    pub fn new(period: usize) -> Result<Self> {
+        if period == 0 {
+            return Err(Error::PeriodZero);
+        }
+        Ok(Self {
+            period,
+            logs: VecDeque::with_capacity(period),
+            sum_logs: 0.0,
+        })
+    }
+
+    /// Configured period.
+    pub const fn period(&self) -> usize {
+        self.period
+    }
+
+    /// Current value if the window is full.
+    pub fn value(&self) -> Option<f64> {
+        if self.logs.len() == self.period {
+            Some((self.sum_logs / self.period as f64).exp())
+        } else {
+            None
+        }
+    }
+}
+
+impl Indicator for GeometricMa {
+    type Input = f64;
+    type Output = f64;
+
+    fn update(&mut self, input: f64) -> Option<f64> {
+        if !input.is_finite() || input <= 0.0 {
+            return self.value();
+        }
+        if self.logs.len() == self.period {
+            let oldest = self.logs.pop_front().expect("window non-empty");
+            self.sum_logs -= oldest;
+        }
+        let ln = input.ln();
+        self.logs.push_back(ln);
+        self.sum_logs += ln;
+        self.value()
+    }
+
+    fn reset(&mut self) {
+        self.logs.clear();
+        self.sum_logs = 0.0;
+    }
+
+    fn warmup_period(&self) -> usize {
+        self.period
+    }
+
+    fn is_ready(&self) -> bool {
+        self.logs.len() == self.period
+    }
+
+    fn name(&self) -> &'static str {
+        "GMA"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    /// Reference implementation: explicit geometric mean over a window.
+    fn gma_naive(prices: &[f64], period: usize) -> Vec<Option<f64>> {
+        prices
+            .iter()
+            .enumerate()
+            .map(|(i, _)| {
+                if i + 1 < period {
+                    None
+                } else {
+                    let window = &prices[i + 1 - period..=i];
+                    let product: f64 = window.iter().product();
+                    Some(product.powf(1.0 / period as f64))
+                }
+            })
+            .collect()
+    }
+
+    #[test]
+    fn new_rejects_zero_period() {
+        assert!(matches!(GeometricMa::new(0), Err(Error::PeriodZero)));
+    }
+
+    /// Cover the const accessor `period` and the Indicator-impl `warmup_period`
+    /// + `name`.
+    #[test]
+    fn accessors_and_metadata() {
+        let gma = GeometricMa::new(7).unwrap();
+        assert_eq!(gma.period(), 7);
+        assert_eq!(gma.warmup_period(), 7);
+        assert_eq!(gma.name(), "GMA");
+    }
+
+    #[test]
+    fn warmup_returns_none() {
+        let mut gma = GeometricMa::new(3).unwrap();
+        assert_eq!(gma.update(1.0), None);
+        assert_eq!(gma.update(4.0), None);
+        // GMA(3) of [1, 4, 2] = (1·4·2)^(1/3) = 8^(1/3) = 2.
+        assert_relative_eq!(gma.update(2.0).unwrap(), 2.0, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn known_value_period_2() {
+        // GMA(2) of [4, 9] = sqrt(36) = 6.
+        let mut gma = GeometricMa::new(2).unwrap();
+        let v = gma.batch(&[4.0, 9.0]);
+        assert_relative_eq!(v[1].unwrap(), 6.0, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn constant_series_returns_the_constant() {
+        let mut gma = GeometricMa::new(5).unwrap();
+        for v in gma.batch(&[42.0; 20]).into_iter().flatten() {
+            assert_relative_eq!(v, 42.0, epsilon = 1e-9);
+        }
+    }
+
+    #[test]
+    fn period_one_is_pass_through() {
+        let mut gma = GeometricMa::new(1).unwrap();
+        assert_relative_eq!(gma.update(5.5).unwrap(), 5.5, epsilon = 1e-12);
+        assert_relative_eq!(gma.update(7.5).unwrap(), 7.5, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn below_or_equal_arithmetic_mean() {
+        // The geometric mean never exceeds the arithmetic mean of the same set.
+        let mut gma = GeometricMa::new(4).unwrap();
+        let prices = [10.0, 20.0, 5.0, 40.0];
+        let g = gma.batch(&prices)[3].unwrap();
+        let arithmetic = prices.iter().sum::<f64>() / 4.0;
+        assert!(
+            g < arithmetic,
+            "geometric {g} should be below arithmetic {arithmetic}"
+        );
+    }
+
+    #[test]
+    fn matches_naive_over_inputs() {
+        let prices: Vec<f64> = (1..=30).map(|i| f64::from(i) * 1.7 + 1.0).collect();
+        let mut gma = GeometricMa::new(7).unwrap();
+        let got = gma.batch(&prices);
+        let want = gma_naive(&prices, 7);
+        for (i, (g, w)) in got.iter().zip(want.iter()).enumerate() {
+            assert_eq!(g.is_some(), w.is_some(), "warmup mismatch at index {i}");
+            if let (Some(a), Some(b)) = (g, w) {
+                assert_relative_eq!(*a, *b, epsilon = 1e-9);
+            }
+        }
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut gma = GeometricMa::new(4).unwrap();
+        gma.batch(&[1.0, 2.0, 3.0, 4.0, 5.0]);
+        assert!(gma.is_ready());
+        gma.reset();
+        assert!(!gma.is_ready());
+        assert_eq!(gma.update(10.0), None);
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let prices: Vec<f64> = (1..=20).map(|i| f64::from(i) * 0.5 + 1.0).collect();
+        let mut a = GeometricMa::new(5).unwrap();
+        let mut b = GeometricMa::new(5).unwrap();
+        assert_eq!(
+            a.batch(&prices),
+            prices.iter().map(|p| b.update(*p)).collect::<Vec<_>>()
+        );
+    }
+
+    #[test]
+    fn ignores_non_finite_and_non_positive_input() {
+        let mut gma = GeometricMa::new(3).unwrap();
+        gma.update(1.0);
+        gma.update(4.0);
+        let ready = gma.update(2.0).expect("GMA(3) ready after three inputs");
+        // Non-finite and non-positive inputs are skipped (geometric mean needs
+        // strictly positive values) and the window is left unchanged.
+        assert_eq!(gma.update(f64::NAN), Some(ready));
+        assert_eq!(gma.update(0.0), Some(ready));
+        assert_eq!(gma.update(-3.0), Some(ready));
+        // The window still holds 1, 4, 2 -> next real input slides it to 4, 2, 16.
+        let want = (4.0_f64 * 2.0 * 16.0).powf(1.0 / 3.0);
+        assert_relative_eq!(gma.update(16.0).unwrap(), want, epsilon = 1e-9);
+    }
+
+    proptest::proptest! {
+        #![proptest_config(proptest::test_runner::Config::with_cases(48))]
+        #[test]
+        fn proptest_matches_naive(
+            period in 1usize..15,
+            prices in proptest::collection::vec(0.01_f64..1000.0, 0..120),
+        ) {
+            let mut gma = GeometricMa::new(period).unwrap();
+            let got = gma.batch(&prices);
+            let want = gma_naive(&prices, period);
+            proptest::prop_assert_eq!(got.len(), want.len());
+            for (g, w) in got.iter().zip(want.iter()) {
+                match (g, w) {
+                    (None, None) => {}
+                    (Some(a), Some(b)) => proptest::prop_assert!(
+                        (a - b).abs() <= 1e-6 * b.abs().max(1.0),
+                        "got={a} want={b}"
+                    ),
+                    _ => proptest::prop_assert!(false, "warmup mismatch"),
+                }
+            }
+        }
+    }
+}
@@ -0,0 +1,174 @@
+//! High-Low Range — the bar range as a fraction of close.
+
+use crate::ohlcv::Candle;
+use crate::traits::Indicator;
+
+/// High-Low Range — the bar's high-low range expressed as a fraction of its
+/// close price.
+///
+/// ```text
+/// HighLowRange = (high − low) / close
+/// ```
+///
+/// A scale-free, single-bar volatility proxy: the absolute range `high − low`
+/// grows with the nominal price level, so dividing by the close makes a `2$`
+/// range on a `100$` instrument (`0.02`) directly comparable to a `200$` range
+/// on a `10000$` one (`0.02`). It is the per-bar cousin of average-true-range
+/// style measures without the smoothing — useful as an instant intrabar
+/// volatility read or a normaliser for other features. The output is `≥ 0`
+/// for positive prices. A zero close carries no scale and yields `0`.
+///
+/// This is a stateless per-bar transform: every candle produces one value.
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Candle, Indicator, HighLowRange};
+///
+/// let mut indicator = HighLowRange::new();
+/// // range 104 - 98 = 6, close 100 -> 0.06.
+/// let c = Candle::new(99.0, 104.0, 98.0, 100.0, 10.0, 0).unwrap();
+/// assert!((indicator.update(c).unwrap() - 0.06).abs() < 1e-12);
+/// ```
+#[derive(Debug, Clone, Default)]
+pub struct HighLowRange {
+    has_emitted: bool,
+}
+
+impl HighLowRange {
+    /// Construct a new High-Low Range transform.
+    pub const fn new() -> Self {
+        Self { has_emitted: false }
+    }
+}
+
+impl Indicator for HighLowRange {
+    type Input = Candle;
+    type Output = f64;
+
+    fn update(&mut self, candle: Candle) -> Option<f64> {
+        self.has_emitted = true;
+        let out = if candle.close == 0.0 {
+            // A zero close carries no scale to normalise the range against.
+            0.0
+        } else {
+            (candle.high - candle.low) / candle.close
+        };
+        Some(out)
+    }
+
+    fn reset(&mut self) {
+        self.has_emitted = false;
+    }
+
+    fn warmup_period(&self) -> usize {
+        1
+    }
+
+    fn is_ready(&self) -> bool {
+        self.has_emitted
+    }
+
+    fn name(&self) -> &'static str {
+        "HighLowRange"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    fn candle(open: f64, high: f64, low: f64, close: f64, ts: i64) -> Candle {
+        Candle::new(open, high, low, close, 1.0, ts).unwrap()
+    }
+
+    #[test]
+    fn reference_value() {
+        // (104 - 98) / 100 = 0.06.
+        let mut hlr = HighLowRange::new();
+        assert_relative_eq!(
+            hlr.update(candle(99.0, 104.0, 98.0, 100.0, 0)).unwrap(),
+            0.06,
+            epsilon = 1e-12
+        );
+    }
+
+    #[test]
+    fn zero_range_bar_yields_zero() {
+        // high == low -> range 0 -> 0 regardless of close.
+        let mut hlr = HighLowRange::new();
+        assert_relative_eq!(
+            hlr.update(candle(10.0, 10.0, 10.0, 10.0, 0)).unwrap(),
+            0.0,
+            epsilon = 1e-12
+        );
+    }
+
+    #[test]
+    fn zero_close_yields_zero() {
+        // Candle permits a zero close (only finiteness + OHLC ordering checked):
+        // open 0, high 1, low 0, close 0 satisfies high >= all, low <= all.
+        let mut hlr = HighLowRange::new();
+        assert_relative_eq!(
+            hlr.update(candle(0.0, 1.0, 0.0, 0.0, 0)).unwrap(),
+            0.0,
+            epsilon = 1e-12
+        );
+    }
+
+    #[test]
+    fn output_is_non_negative() {
+        let candles: Vec<Candle> = (0..100)
+            .map(|i| {
+                let mid = 100.0 + (f64::from(i) * 0.2).sin() * 8.0;
+                candle(mid, mid + 3.0, mid - 3.0, mid, i64::from(i))
+            })
+            .collect();
+        let mut hlr = HighLowRange::new();
+        for v in hlr.batch(&candles).into_iter().flatten() {
+            assert!(v >= 0.0, "HighLowRange {v} must be non-negative");
+        }
+    }
+
+    #[test]
+    fn name_metadata() {
+        let hlr = HighLowRange::new();
+        assert_eq!(hlr.name(), "HighLowRange");
+    }
+
+    #[test]
+    fn emits_from_first_candle() {
+        let mut hlr = HighLowRange::new();
+        assert_eq!(hlr.warmup_period(), 1);
+        assert!(!hlr.is_ready());
+        assert!(hlr.update(candle(10.0, 11.0, 9.0, 10.0, 0)).is_some());
+        assert!(hlr.is_ready());
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut hlr = HighLowRange::new();
+        hlr.update(candle(10.0, 11.0, 9.0, 10.0, 0));
+        assert!(hlr.is_ready());
+        hlr.reset();
+        assert!(!hlr.is_ready());
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let candles: Vec<Candle> = (0..40)
+            .map(|i| {
+                let base = 100.0 + f64::from(i);
+                candle(base, base + 2.0, base - 2.0, base + 1.0, i64::from(i))
+            })
+            .collect();
+        let mut a = HighLowRange::new();
+        let mut b = HighLowRange::new();
+        assert_eq!(
+            a.batch(&candles),
+            candles.iter().map(|x| b.update(*x)).collect::<Vec<_>>()
+        );
+    }
+}
@@ -0,0 +1,215 @@
+//! Ehlers two-pole Highpass Filter — removes the trend, keeps the cycles.
+#![allow(clippy::doc_markdown)]
+
+use std::f64::consts::PI;
+
+use crate::error::{Error, Result};
+use crate::traits::Indicator;
+
+/// Ehlers' two-pole Highpass Filter — strips the low-frequency trend from a price
+/// series, leaving the higher-frequency cyclic and noise content.
+///
+/// From John Ehlers' *Cycle Analytics for Traders* (2013):
+///
+/// ```text
+/// a = 0.707 · 2π / period
+/// alpha1 = (cos(a) + sin(a) − 1) / cos(a)
+/// HP_t = (1 − alpha1/2)² · (price_t − 2·price_{t−1} + price_{t−2})
+///        + 2·(1 − alpha1)·HP_{t−1} − (1 − alpha1)²·HP_{t−2}
+/// ```
+///
+/// A highpass filter is the complement of a smoother: where a lowpass keeps the
+/// trend, the highpass keeps everything *faster* than the cutoff `period`. The
+/// two-pole design gives a steep roll-off so frequencies below the cutoff are
+/// firmly removed, detrending the series into a zero-mean wave. This differs from
+/// the [`Decycler`](crate::Decycler), which is `price − highpass` (the *trend* that
+/// remains); the highpass is the cyclic part that the decycler discards.
+///
+/// The recursion needs two prior prices and two prior outputs; until then it emits
+/// `0`, so `warmup_period` is `1`. Each `update` is O(1).
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Indicator, HighpassFilter};
+///
+/// let mut indicator = HighpassFilter::new(48).unwrap();
+/// let mut last = None;
+/// for i in 0..120 {
+///     last = indicator.update(100.0 + f64::from(i) + (f64::from(i) * 0.5).sin() * 3.0);
+/// }
+/// assert!(last.is_some());
+/// ```
+#[derive(Debug, Clone)]
+pub struct HighpassFilter {
+    period: usize,
+    alpha1: f64,
+    prev_price_1: Option<f64>,
+    prev_price_2: Option<f64>,
+    hp1: f64,
+    hp2: f64,
+    last: Option<f64>,
+}
+
+impl HighpassFilter {
+    /// Construct a two-pole highpass filter with the given cutoff `period`.
+    ///
+    /// # Errors
+    ///
+    /// Returns [`Error::PeriodZero`] if `period == 0`.
+    pub fn new(period: usize) -> Result<Self> {
+        if period == 0 {
+            return Err(Error::PeriodZero);
+        }
+        let a = 0.707 * 2.0 * PI / period as f64;
+        let alpha1 = (a.cos() + a.sin() - 1.0) / a.cos();
+        Ok(Self {
+            period,
+            alpha1,
+            prev_price_1: None,
+            prev_price_2: None,
+            hp1: 0.0,
+            hp2: 0.0,
+            last: None,
+        })
+    }
+
+    /// Configured cutoff period.
+    pub const fn period(&self) -> usize {
+        self.period
+    }
+
+    /// Current value if available.
+    pub const fn value(&self) -> Option<f64> {
+        self.last
+    }
+}
+
+impl Indicator for HighpassFilter {
+    type Input = f64;
+    type Output = f64;
+
+    fn update(&mut self, price: f64) -> Option<f64> {
+        if !price.is_finite() {
+            return self.last;
+        }
+        let hp = match (self.prev_price_1, self.prev_price_2) {
+            (Some(p1), Some(p2)) => {
+                let one_minus = 1.0 - self.alpha1;
+                let half = 1.0 - self.alpha1 / 2.0;
+                half * half * (price - 2.0 * p1 + p2) + 2.0 * one_minus * self.hp1
+                    - one_minus * one_minus * self.hp2
+            }
+            _ => 0.0,
+        };
+        self.prev_price_2 = self.prev_price_1;
+        self.prev_price_1 = Some(price);
+        self.hp2 = self.hp1;
+        self.hp1 = hp;
+        self.last = Some(hp);
+        Some(hp)
+    }
+
+    fn reset(&mut self) {
+        self.prev_price_1 = None;
+        self.prev_price_2 = None;
+        self.hp1 = 0.0;
+        self.hp2 = 0.0;
+        self.last = None;
+    }
+
+    fn warmup_period(&self) -> usize {
+        1
+    }
+
+    fn is_ready(&self) -> bool {
+        self.last.is_some()
+    }
+
+    fn name(&self) -> &'static str {
+        "HighpassFilter"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    #[test]
+    fn rejects_zero_period() {
+        assert!(matches!(HighpassFilter::new(0), Err(Error::PeriodZero)));
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let hp = HighpassFilter::new(48).unwrap();
+        assert_eq!(hp.period(), 48);
+        assert_eq!(hp.warmup_period(), 1);
+        assert_eq!(hp.name(), "HighpassFilter");
+        assert!(!hp.is_ready());
+        assert_eq!(hp.value(), None);
+    }
+
+    #[test]
+    fn first_bars_are_zero() {
+        let mut hp = HighpassFilter::new(48).unwrap();
+        assert_eq!(hp.update(100.0), Some(0.0));
+        assert_eq!(hp.update(101.0), Some(0.0));
+        assert!(hp.is_ready());
+    }
+
+    #[test]
+    fn constant_input_stays_zero() {
+        let mut hp = HighpassFilter::new(48).unwrap();
+        for v in hp.batch(&[50.0; 200]).into_iter().flatten() {
+            assert_relative_eq!(v, 0.0, epsilon = 1e-9);
+        }
+    }
+
+    #[test]
+    fn pure_trend_is_attenuated() {
+        // A straight ramp is low-frequency -> the highpass should drive its
+        // output small after warmup (the trend is removed).
+        let mut hp = HighpassFilter::new(20).unwrap();
+        let out: Vec<f64> = hp
+            .batch(&(0..400).map(f64::from).collect::<Vec<_>>())
+            .into_iter()
+            .flatten()
+            .skip(200)
+            .collect();
+        for v in out {
+            assert!(v.abs() < 5.0, "trend should be attenuated, got {v}");
+        }
+    }
+
+    #[test]
+    fn ignores_non_finite() {
+        let mut hp = HighpassFilter::new(48).unwrap();
+        hp.batch(&(0..40).map(f64::from).collect::<Vec<_>>());
+        let before = hp.value();
+        assert_eq!(hp.update(f64::NAN), before);
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut hp = HighpassFilter::new(48).unwrap();
+        hp.batch(&(0..40).map(f64::from).collect::<Vec<_>>());
+        assert!(hp.is_ready());
+        hp.reset();
+        assert!(!hp.is_ready());
+        assert_eq!(hp.update(100.0), Some(0.0));
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let xs: Vec<f64> = (0..120)
+            .map(|i| 100.0 + f64::from(i) + (f64::from(i) * 0.25).sin() * 9.0)
+            .collect();
+        let batch = HighpassFilter::new(48).unwrap().batch(&xs);
+        let mut b = HighpassFilter::new(48).unwrap();
+        let streamed: Vec<_> = xs.iter().map(|x| b.update(*x)).collect();
+        assert_eq!(batch, streamed);
+    }
+}
@@ -0,0 +1,315 @@
+//! Holt's linear (double exponential) smoothing.
+
+use crate::error::{Error, Result};
+use crate::traits::Indicator;
+
+/// Holt's linear method — double exponential smoothing with a level and a
+/// trend component.
+///
+/// A single [`Ema`](crate::Ema) tracks only a *level* and therefore lags any
+/// sustained trend. Holt's method adds a second smoothed state, the trend, and
+/// reports the one-step-ahead forecast `level + trend`, which removes that lag
+/// on trending data while still smoothing noise.
+///
+/// ```text
+/// level_t = α · price_t        + (1 − α) · (level_{t-1} + trend_{t-1})
+/// trend_t = β · (level_t − level_{t-1}) + (1 − β) · trend_{t-1}
+/// output  = level_t + trend_t          (one-step-ahead forecast)
+/// ```
+///
+/// `α ∈ (0, 1]` is the level smoothing constant and `β ∈ (0, 1]` the trend
+/// smoothing constant. The state is seeded from the first two inputs
+/// (`level = price_1`, `trend = price_1 − price_0`), so the first output lands
+/// on the **second** input.
+///
+/// On a perfectly linear series the forecast is exact from the second bar
+/// onward (for any `α`, `β`): if the level equals the current value and the
+/// trend equals the slope, both invariants are preserved and `level + trend`
+/// equals the next value.
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{HoltWinters, Indicator};
+///
+/// let mut indicator = HoltWinters::new(0.2, 0.1).unwrap();
+/// let mut last = None;
+/// for i in 0..80 {
+///     last = indicator.update(100.0 + f64::from(i));
+/// }
+/// assert!(last.is_some());
+/// ```
+#[derive(Debug, Clone)]
+pub struct HoltWinters {
+    alpha: f64,
+    beta: f64,
+    /// `(level, trend)` once seeded.
+    state: Option<(f64, f64)>,
+    /// First input, held until the second arrives to seed the trend.
+    prev_price: Option<f64>,
+}
+
+impl HoltWinters {
+    /// Construct Holt's linear smoother with level constant `alpha` and trend
+    /// constant `beta`.
+    ///
+    /// # Errors
+    ///
+    /// Returns [`Error::InvalidPeriod`] if either constant is non-finite or
+    /// outside `(0.0, 1.0]`.
+    pub fn new(alpha: f64, beta: f64) -> Result<Self> {
+        if !alpha.is_finite() || alpha <= 0.0 || alpha > 1.0 {
+            return Err(Error::InvalidPeriod {
+                message: "HoltWinters alpha must be in (0.0, 1.0]",
+            });
+        }
+        if !beta.is_finite() || beta <= 0.0 || beta > 1.0 {
+            return Err(Error::InvalidPeriod {
+                message: "HoltWinters beta must be in (0.0, 1.0]",
+            });
+        }
+        Ok(Self {
+            alpha,
+            beta,
+            state: None,
+            prev_price: None,
+        })
+    }
+
+    /// Level smoothing constant `alpha`.
+    pub const fn alpha(&self) -> f64 {
+        self.alpha
+    }
+
+    /// Trend smoothing constant `beta`.
+    pub const fn beta(&self) -> f64 {
+        self.beta
+    }
+
+    /// Current smoothed level, if seeded.
+    pub fn level(&self) -> Option<f64> {
+        self.state.map(|(level, _)| level)
+    }
+
+    /// Current smoothed trend, if seeded.
+    pub fn trend(&self) -> Option<f64> {
+        self.state.map(|(_, trend)| trend)
+    }
+
+    /// Current one-step-ahead forecast `level + trend`, if seeded.
+    pub fn value(&self) -> Option<f64> {
+        self.state.map(|(level, trend)| level + trend)
+    }
+}
+
+impl Indicator for HoltWinters {
+    type Input = f64;
+    type Output = f64;
+
+    fn update(&mut self, price: f64) -> Option<f64> {
+        if !price.is_finite() {
+            return self.value();
+        }
+        match self.state {
+            None => {
+                if let Some(prev) = self.prev_price {
+                    // Second input: seed level and trend.
+                    let level = price;
+                    let trend = price - prev;
+                    self.state = Some((level, trend));
+                    Some(level + trend)
+                } else {
+                    // First input: hold it to seed the trend next time.
+                    self.prev_price = Some(price);
+                    None
+                }
+            }
+            Some((level, trend)) => {
+                let level_new = self.alpha * price + (1.0 - self.alpha) * (level + trend);
+                let trend_new = self.beta * (level_new - level) + (1.0 - self.beta) * trend;
+                self.state = Some((level_new, trend_new));
+                Some(level_new + trend_new)
+            }
+        }
+    }
+
+    fn reset(&mut self) {
+        self.state = None;
+        self.prev_price = None;
+    }
+
+    fn warmup_period(&self) -> usize {
+        // Two inputs are needed to seed the level and the trend.
+        2
+    }
+
+    fn is_ready(&self) -> bool {
+        self.state.is_some()
+    }
+
+    fn name(&self) -> &'static str {
+        "HoltWinters"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    /// Independent reference for the steady-state recurrence.
+    fn naive(prices: &[f64], alpha: f64, beta: f64) -> Vec<Option<f64>> {
+        let mut state: Option<(f64, f64)> = None;
+        let mut prev: Option<f64> = None;
+        let mut out = Vec::with_capacity(prices.len());
+        for &price in prices {
+            let v = match state {
+                None => {
+                    if let Some(p0) = prev {
+                        let level = price;
+                        let trend = price - p0;
+                        state = Some((level, trend));
+                        Some(level + trend)
+                    } else {
+                        prev = Some(price);
+                        None
+                    }
+                }
+                Some((level, trend)) => {
+                    let ln = alpha * price + (1.0 - alpha) * (level + trend);
+                    let tn = beta * (ln - level) + (1.0 - beta) * trend;
+                    state = Some((ln, tn));
+                    Some(ln + tn)
+                }
+            };
+            out.push(v);
+        }
+        out
+    }
+
+    #[test]
+    fn rejects_invalid_alpha() {
+        assert!(matches!(
+            HoltWinters::new(0.0, 0.1),
+            Err(Error::InvalidPeriod { .. })
+        ));
+        assert!(matches!(
+            HoltWinters::new(1.5, 0.1),
+            Err(Error::InvalidPeriod { .. })
+        ));
+        assert!(matches!(
+            HoltWinters::new(f64::NAN, 0.1),
+            Err(Error::InvalidPeriod { .. })
+        ));
+    }
+
+    #[test]
+    fn rejects_invalid_beta() {
+        assert!(matches!(
+            HoltWinters::new(0.2, 0.0),
+            Err(Error::InvalidPeriod { .. })
+        ));
+        assert!(matches!(
+            HoltWinters::new(0.2, 1.5),
+            Err(Error::InvalidPeriod { .. })
+        ));
+        assert!(matches!(
+            HoltWinters::new(0.2, f64::INFINITY),
+            Err(Error::InvalidPeriod { .. })
+        ));
+    }
+
+    /// Cover the const accessors `alpha` + `beta` and the Indicator-impl
+    /// `warmup_period` + `name`.
+    #[test]
+    fn accessors_and_metadata() {
+        let hw = HoltWinters::new(0.2, 0.1).unwrap();
+        assert_relative_eq!(hw.alpha(), 0.2, epsilon = 1e-12);
+        assert_relative_eq!(hw.beta(), 0.1, epsilon = 1e-12);
+        assert_eq!(hw.warmup_period(), 2);
+        assert_eq!(hw.name(), "HoltWinters");
+    }
+
+    #[test]
+    fn warmup_then_seed_on_second_input() {
+        let mut hw = HoltWinters::new(0.2, 0.1).unwrap();
+        assert_eq!(hw.update(10.0), None);
+        // Second input seeds level = 12, trend = 12 - 10 = 2 -> forecast 14.
+        assert_relative_eq!(hw.update(12.0).unwrap(), 14.0, epsilon = 1e-12);
+        assert_relative_eq!(hw.level().unwrap(), 12.0, epsilon = 1e-12);
+        assert_relative_eq!(hw.trend().unwrap(), 2.0, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn linear_series_forecasts_exactly() {
+        // On a perfect ramp the one-step forecast equals the next value, for
+        // any alpha/beta, from the second bar onward.
+        let prices: Vec<f64> = (1..=20).map(f64::from).collect();
+        let mut hw = HoltWinters::new(0.3, 0.4).unwrap();
+        let out = hw.batch(&prices);
+        assert!(out[0].is_none());
+        for (i, v) in out.iter().enumerate().skip(1) {
+            // forecast at index i is the price at index i + 1 = (i + 2).
+            assert_relative_eq!(v.unwrap(), (i + 2) as f64, epsilon = 1e-9);
+        }
+    }
+
+    #[test]
+    fn constant_series_yields_constant() {
+        let mut hw = HoltWinters::new(0.2, 0.1).unwrap();
+        let out = hw.batch(&[42.0_f64; 30]);
+        for v in out.into_iter().skip(1).flatten() {
+            assert_relative_eq!(v, 42.0, epsilon = 1e-9);
+        }
+    }
+
+    #[test]
+    fn matches_naive_recurrence() {
+        let prices: Vec<f64> = (0..60)
+            .map(|i| 100.0 + (f64::from(i) * 0.3).sin() * 10.0 + f64::from(i) * 0.2)
+            .collect();
+        let mut hw = HoltWinters::new(0.25, 0.15).unwrap();
+        let got = hw.batch(&prices);
+        let want = naive(&prices, 0.25, 0.15);
+        for (g, w) in got.iter().zip(want.iter()) {
+            assert_eq!(g.is_some(), w.is_some());
+            if let (Some(a), Some(b)) = (g, w) {
+                assert_relative_eq!(a, b, epsilon = 1e-9);
+            }
+        }
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut hw = HoltWinters::new(0.2, 0.1).unwrap();
+        hw.batch(&(1..=20).map(f64::from).collect::<Vec<_>>());
+        assert!(hw.is_ready());
+        hw.reset();
+        assert!(!hw.is_ready());
+        assert_eq!(hw.update(1.0), None);
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let prices: Vec<f64> = (1..=30).map(|i| f64::from(i) * 0.5).collect();
+        let mut a = HoltWinters::new(0.3, 0.2).unwrap();
+        let mut b = HoltWinters::new(0.3, 0.2).unwrap();
+        assert_eq!(
+            a.batch(&prices),
+            prices.iter().map(|p| b.update(*p)).collect::<Vec<_>>()
+        );
+    }
+
+    #[test]
+    fn ignores_non_finite_input() {
+        let mut hw = HoltWinters::new(0.2, 0.1).unwrap();
+        // Non-finite before any state returns None.
+        assert_eq!(hw.update(f64::NAN), None);
+        hw.update(10.0);
+        let ready = hw.update(12.0).expect("seeded on second finite input");
+        // Non-finite after seeding returns the current forecast unchanged.
+        assert_eq!(hw.update(f64::NAN), Some(ready));
+        assert_eq!(hw.update(f64::INFINITY), Some(ready));
+    }
+}
@@ -0,0 +1,185 @@
+//! Intraday Intensity Index (Bostian) — a cumulative volume-weighted close-location line.
+
+use crate::ohlcv::Candle;
+use crate::traits::Indicator;
+
+/// Intraday Intensity Index — David Bostian's cumulative line that weights each
+/// bar's volume by where the close lands inside the bar's range.
+///
+/// ```text
+/// II_t  = volume * (2*close − high − low) / (high − low)   (0 if high == low)
+/// III_t = III_{t−1} + II_t
+/// ```
+///
+/// The fraction `(2*close − high − low) / (high − low)` is `+1` when the bar
+/// closes on its high, `−1` when it closes on its low, and `0` at the midpoint.
+/// Scaling it by volume and accumulating produces a running measure of how
+/// aggressively the close is being pushed toward the extremes — Bostian's proxy
+/// for institutional accumulation (rising line) or distribution (falling line).
+///
+/// This is the **cumulative** Intraday Intensity (the original index), not the
+/// normalized "Intraday Intensity %" — the latter divides a windowed sum of `II`
+/// by a windowed sum of volume and is mathematically identical to
+/// [`Cmf`](crate::Cmf), so it is not duplicated here. The level of this line is
+/// arbitrary; only its slope and divergences against price matter. A doji whose
+/// `high == low` contributes nothing. Each `update` is O(1) and the first bar
+/// already emits a value.
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Candle, Indicator, IntradayIntensity};
+///
+/// let mut indicator = IntradayIntensity::new();
+/// let mut last = None;
+/// for i in 0..20 {
+///     let base = 100.0 + f64::from(i);
+///     let c = Candle::new(base, base + 1.0, base - 1.0, base + 0.9, 1_000.0, 0).unwrap();
+///     last = indicator.update(c);
+/// }
+/// assert!(last.is_some());
+/// ```
+#[derive(Debug, Clone, Default)]
+pub struct IntradayIntensity {
+    iii: f64,
+    last: Option<f64>,
+}
+
+impl IntradayIntensity {
+    /// Construct a new Intraday Intensity Index. The line is parameter-free.
+    #[must_use]
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// Current value if available.
+    pub const fn value(&self) -> Option<f64> {
+        self.last
+    }
+}
+
+impl Indicator for IntradayIntensity {
+    type Input = Candle;
+    type Output = f64;
+
+    fn update(&mut self, candle: Candle) -> Option<f64> {
+        let range = candle.high - candle.low;
+        let ii = if range > 0.0 {
+            candle.volume * (2.0 * candle.close - candle.high - candle.low) / range
+        } else {
+            0.0
+        };
+        self.iii += ii;
+        self.last = Some(self.iii);
+        Some(self.iii)
+    }
+
+    fn reset(&mut self) {
+        self.iii = 0.0;
+        self.last = None;
+    }
+
+    fn warmup_period(&self) -> usize {
+        1
+    }
+
+    fn is_ready(&self) -> bool {
+        self.last.is_some()
+    }
+
+    fn name(&self) -> &'static str {
+        "IntradayIntensity"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    fn candle(high: f64, low: f64, close: f64, volume: f64) -> Candle {
+        Candle::new_unchecked(low, high, low, close, volume, 0)
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let iii = IntradayIntensity::new();
+        assert_eq!(iii.warmup_period(), 1);
+        assert_eq!(iii.name(), "IntradayIntensity");
+        assert!(!iii.is_ready());
+        assert_eq!(iii.value(), None);
+    }
+
+    #[test]
+    fn first_bar_emits() {
+        // close at the high: (2*101 - 102 - 100)/(2) = 0/... wait, high=102 low=100 close=101 -> 0.
+        let mut iii = IntradayIntensity::new();
+        // close on the high -> +1 * volume.
+        let v = iii.update(candle(102.0, 100.0, 102.0, 500.0)).unwrap();
+        assert_relative_eq!(v, 500.0, epsilon = 1e-9);
+    }
+
+    #[test]
+    fn close_on_high_adds_full_volume() {
+        let mut iii = IntradayIntensity::new();
+        let v = iii.update(candle(110.0, 100.0, 110.0, 1_000.0)).unwrap();
+        assert_relative_eq!(v, 1_000.0, epsilon = 1e-9);
+    }
+
+    #[test]
+    fn close_on_low_subtracts_full_volume() {
+        let mut iii = IntradayIntensity::new();
+        let v = iii.update(candle(110.0, 100.0, 100.0, 1_000.0)).unwrap();
+        assert_relative_eq!(v, -1_000.0, epsilon = 1e-9);
+    }
+
+    #[test]
+    fn close_at_midpoint_adds_nothing() {
+        let mut iii = IntradayIntensity::new();
+        let v = iii.update(candle(110.0, 100.0, 105.0, 1_000.0)).unwrap();
+        assert_relative_eq!(v, 0.0, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn zero_range_adds_nothing() {
+        let mut iii = IntradayIntensity::new();
+        let v = iii.update(candle(100.0, 100.0, 100.0, 1_000.0)).unwrap();
+        assert_relative_eq!(v, 0.0, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn accumulates_across_bars() {
+        let mut iii = IntradayIntensity::new();
+        iii.update(candle(110.0, 100.0, 110.0, 1_000.0)); // +1000
+        let v = iii.update(candle(110.0, 100.0, 100.0, 400.0)).unwrap(); // -400 -> 600
+        assert_relative_eq!(v, 600.0, epsilon = 1e-9);
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut iii = IntradayIntensity::new();
+        iii.batch(&[
+            candle(110.0, 100.0, 108.0, 1.0),
+            candle(110.0, 100.0, 102.0, 1.0),
+        ]);
+        assert!(iii.is_ready());
+        iii.reset();
+        assert!(!iii.is_ready());
+        assert_eq!(iii.value(), None);
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let candles: Vec<Candle> = (0..80)
+            .map(|i| {
+                let base = 100.0 + (f64::from(i) * 0.3).sin() * 6.0;
+                candle(base + 2.0, base - 2.0, base + 0.7, 1_000.0 + f64::from(i))
+            })
+            .collect();
+        let batch = IntradayIntensity::new().batch(&candles);
+        let mut b = IntradayIntensity::new();
+        let streamed: Vec<_> = candles.iter().map(|c| b.update(*c)).collect();
+        assert_eq!(batch, streamed);
+    }
+}
@@ -0,0 +1,228 @@
+//! Intraday Momentum Index (IMI).
+
+use std::collections::VecDeque;
+
+use crate::error::{Error, Result};
+use crate::ohlcv::Candle;
+use crate::traits::Indicator;
+
+/// Intraday Momentum Index — Tushar Chande's RSI built from the open-to-close
+/// move instead of the close-to-close move.
+///
+/// For each bar the body is an up-move when `close > open` and a down-move
+/// otherwise; the IMI sums those bodies over `period` bars and forms the
+/// RSI-style ratio:
+///
+/// ```text
+/// gain = max(close - open, 0),  loss = max(open - close, 0)
+/// IMI  = 100 * Σ gain / (Σ gain + Σ loss)        over the last `period` bars
+/// ```
+///
+/// Because it measures *intraday* (body) momentum rather than the gap-inclusive
+/// close-to-close change, the IMI is a candle-pattern-flavoured overbought /
+/// oversold gauge: persistent white bodies push it up, black bodies down. It is
+/// bounded in `[0, 100]`; a window of doji-like bars (no net bodies) returns the
+/// neutral `50`.
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Candle, IntradayMomentumIndex, Indicator};
+///
+/// let mut imi = IntradayMomentumIndex::new(14).unwrap();
+/// let mut last = None;
+/// for i in 0..40 {
+///     let base = 100.0 + f64::from(i);
+///     let c = Candle::new(base, base + 1.0, base - 1.0, base + 0.5, 1.0, i64::from(i)).unwrap();
+///     last = imi.update(c);
+/// }
+/// assert!(last.is_some());
+/// ```
+#[derive(Debug, Clone)]
+pub struct IntradayMomentumIndex {
+    period: usize,
+    /// Per-bar `(gain, loss)` bodies, oldest at the front.
+    window: VecDeque<(f64, f64)>,
+    sum_gain: f64,
+    sum_loss: f64,
+}
+
+impl IntradayMomentumIndex {
+    /// Construct an IMI over `period` bars.
+    ///
+    /// # Errors
+    ///
+    /// Returns [`Error::PeriodZero`] if `period == 0`.
+    pub fn new(period: usize) -> Result<Self> {
+        if period == 0 {
+            return Err(Error::PeriodZero);
+        }
+        Ok(Self {
+            period,
+            window: VecDeque::with_capacity(period),
+            sum_gain: 0.0,
+            sum_loss: 0.0,
+        })
+    }
+
+    /// Configured period.
+    pub const fn period(&self) -> usize {
+        self.period
+    }
+
+    /// Current value if the window is full.
+    pub fn value(&self) -> Option<f64> {
+        if self.window.len() != self.period {
+            return None;
+        }
+        let denom = self.sum_gain + self.sum_loss;
+        if denom == 0.0 {
+            Some(50.0)
+        } else {
+            Some(100.0 * self.sum_gain / denom)
+        }
+    }
+}
+
+impl Indicator for IntradayMomentumIndex {
+    type Input = Candle;
+    type Output = f64;
+
+    fn update(&mut self, candle: Candle) -> Option<f64> {
+        let body = candle.close - candle.open;
+        let gain = if body > 0.0 { body } else { 0.0 };
+        let loss = if body < 0.0 { -body } else { 0.0 };
+
+        if self.window.len() == self.period {
+            let (old_g, old_l) = self.window.pop_front().expect("window full");
+            self.sum_gain -= old_g;
+            self.sum_loss -= old_l;
+        }
+        self.window.push_back((gain, loss));
+        self.sum_gain += gain;
+        self.sum_loss += loss;
+        self.value()
+    }
+
+    fn reset(&mut self) {
+        self.window.clear();
+        self.sum_gain = 0.0;
+        self.sum_loss = 0.0;
+    }
+
+    fn warmup_period(&self) -> usize {
+        self.period
+    }
+
+    fn is_ready(&self) -> bool {
+        self.window.len() == self.period
+    }
+
+    fn name(&self) -> &'static str {
+        "IMI"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    fn candle(open: f64, close: f64) -> Candle {
+        let hi = open.max(close) + 1.0;
+        let lo = open.min(close) - 1.0;
+        Candle::new(open, hi, lo, close, 1.0, 0).unwrap()
+    }
+
+    #[test]
+    fn rejects_zero_period() {
+        assert!(matches!(
+            IntradayMomentumIndex::new(0),
+            Err(Error::PeriodZero)
+        ));
+    }
+
+    /// Cover the const accessor `period` and the Indicator-impl `warmup_period`
+    /// + `name`.
+    #[test]
+    fn accessors_and_metadata() {
+        let imi = IntradayMomentumIndex::new(14).unwrap();
+        assert_eq!(imi.period(), 14);
+        assert_eq!(imi.warmup_period(), 14);
+        assert_eq!(imi.name(), "IMI");
+    }
+
+    #[test]
+    fn all_up_bodies_is_one_hundred() {
+        let mut imi = IntradayMomentumIndex::new(3).unwrap();
+        let bars = [candle(10.0, 11.0), candle(11.0, 13.0), candle(13.0, 14.0)];
+        let out = imi.batch(&bars);
+        assert!(out[0].is_none());
+        assert!(out[1].is_none());
+        assert_relative_eq!(out[2].unwrap(), 100.0, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn all_down_bodies_is_zero() {
+        let mut imi = IntradayMomentumIndex::new(3).unwrap();
+        let bars = [candle(14.0, 13.0), candle(13.0, 11.0), candle(11.0, 10.0)];
+        assert_relative_eq!(imi.batch(&bars)[2].unwrap(), 0.0, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn known_value_mixed_bodies() {
+        // bodies: +1, -1, +2 -> sum_gain = 3, sum_loss = 1 -> 100*3/4 = 75.
+        let mut imi = IntradayMomentumIndex::new(3).unwrap();
+        let bars = [candle(10.0, 11.0), candle(11.0, 10.0), candle(10.0, 12.0)];
+        assert_relative_eq!(imi.batch(&bars)[2].unwrap(), 75.0, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn doji_window_is_neutral() {
+        // close == open every bar -> no bodies -> neutral 50.
+        let mut imi = IntradayMomentumIndex::new(3).unwrap();
+        let bars = [candle(10.0, 10.0), candle(11.0, 11.0), candle(12.0, 12.0)];
+        assert_relative_eq!(imi.batch(&bars)[2].unwrap(), 50.0, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn slides_window() {
+        // After [+1,-1,+2] (75) add +0 body window -> [-1,+2,0]: gain 2, loss 1 -> 66.67.
+        let mut imi = IntradayMomentumIndex::new(3).unwrap();
+        let bars = [
+            candle(10.0, 11.0),
+            candle(11.0, 10.0),
+            candle(10.0, 12.0),
+            candle(12.0, 12.0),
+        ];
+        let out = imi.batch(&bars);
+        assert_relative_eq!(out[3].unwrap(), 100.0 * 2.0 / 3.0, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut imi = IntradayMomentumIndex::new(3).unwrap();
+        imi.batch(&[candle(10.0, 11.0), candle(11.0, 12.0), candle(12.0, 13.0)]);
+        assert!(imi.is_ready());
+        imi.reset();
+        assert!(!imi.is_ready());
+        assert_eq!(imi.update(candle(1.0, 2.0)), None);
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let bars: Vec<Candle> = (0..30)
+            .map(|i| {
+                let base = 100.0 + f64::from(i);
+                candle(base, base + (f64::from(i) * 0.5).sin())
+            })
+            .collect();
+        let mut a = IntradayMomentumIndex::new(7).unwrap();
+        let mut b = IntradayMomentumIndex::new(7).unwrap();
+        assert_eq!(
+            a.batch(&bars),
+            bars.iter().map(|c| b.update(*c)).collect::<Vec<_>>()
+        );
+    }
+}
@@ -0,0 +1,263 @@
+//! Jarque-Bera — a normality-test statistic on a rolling window.
+
+use std::collections::VecDeque;
+
+use crate::error::{Error, Result};
+use crate::traits::Indicator;
+
+/// Jarque-Bera — the Jarque-Bera test statistic measuring how far a window's
+/// distribution departs from normal, via its **skewness** and **excess
+/// kurtosis**.
+///
+/// ```text
+/// S  = skewness         = m3 / m2^(3/2)
+/// K  = excess kurtosis  = m4 / m2²  − 3
+/// JB = (period / 6) · ( S² + K²/4 )
+/// ```
+///
+/// where `m2`, `m3`, `m4` are the second, third and fourth central moments of the
+/// window. A perfectly normal sample has zero skew and zero excess kurtosis, so
+/// `JB = 0`; the statistic grows as the distribution becomes asymmetric (non-zero
+/// skew) or fat- or thin-tailed (non-zero excess kurtosis). Under the null of
+/// normality `JB` is asymptotically χ² with two degrees of freedom, so values
+/// above roughly `6` reject normality at the 95% level — a useful streaming flag
+/// for fat-tail / crash-risk regimes in a return series.
+///
+/// The statistic is `≥ 0`. A degenerate window with zero variance (`m2 == 0`)
+/// returns `0`. The first value lands after `period` inputs; each `update`
+/// recomputes the four moments over the window in O(`period`).
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Indicator, JarqueBera};
+///
+/// let mut indicator = JarqueBera::new(50).unwrap();
+/// let mut last = None;
+/// for i in 0..80 {
+///     last = indicator.update((f64::from(i) * 0.3).sin());
+/// }
+/// assert!(last.is_some());
+/// ```
+#[derive(Debug, Clone)]
+pub struct JarqueBera {
+    period: usize,
+    window: VecDeque<f64>,
+    last: Option<f64>,
+}
+
+impl JarqueBera {
+    /// Construct a rolling Jarque-Bera over `period` values.
+    ///
+    /// # Errors
+    ///
+    /// Returns [`Error::PeriodZero`] if `period == 0` and
+    /// [`Error::InvalidPeriod`] if `period < 4` (the statistic is degenerate on
+    /// fewer than four points).
+    pub fn new(period: usize) -> Result<Self> {
+        if period == 0 {
+            return Err(Error::PeriodZero);
+        }
+        if period < 4 {
+            return Err(Error::InvalidPeriod {
+                message: "Jarque-Bera needs period >= 4",
+            });
+        }
+        Ok(Self {
+            period,
+            window: VecDeque::with_capacity(period),
+            last: None,
+        })
+    }
+
+    /// Configured window length.
+    pub const fn period(&self) -> usize {
+        self.period
+    }
+
+    /// Current value if available.
+    pub const fn value(&self) -> Option<f64> {
+        self.last
+    }
+
+    fn compute(&self) -> f64 {
+        let n = self.period as f64;
+        let mean = self.window.iter().sum::<f64>() / n;
+        let mut m2 = 0.0;
+        let mut m3 = 0.0;
+        let mut m4 = 0.0;
+        for &v in &self.window {
+            let d = v - mean;
+            let d2 = d * d;
+            m2 += d2;
+            m3 += d2 * d;
+            m4 += d2 * d2;
+        }
+        m2 /= n;
+        m3 /= n;
+        m4 /= n;
+        if m2 == 0.0 {
+            return 0.0;
+        }
+        let skew = m3 / m2.powf(1.5);
+        let excess_kurt = m4 / (m2 * m2) - 3.0;
+        (n / 6.0) * (skew * skew + excess_kurt * excess_kurt / 4.0)
+    }
+}
+
+impl Indicator for JarqueBera {
+    type Input = f64;
+    type Output = f64;
+
+    fn update(&mut self, input: f64) -> Option<f64> {
+        if !input.is_finite() {
+            return self.last;
+        }
+        if self.window.len() == self.period {
+            self.window.pop_front();
+        }
+        self.window.push_back(input);
+        if self.window.len() < self.period {
+            return None;
+        }
+        let out = self.compute();
+        self.last = Some(out);
+        Some(out)
+    }
+
+    fn reset(&mut self) {
+        self.window.clear();
+        self.last = None;
+    }
+
+    fn warmup_period(&self) -> usize {
+        self.period
+    }
+
+    fn is_ready(&self) -> bool {
+        self.last.is_some()
+    }
+
+    fn name(&self) -> &'static str {
+        "JarqueBera"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    #[test]
+    fn rejects_invalid_period() {
+        assert!(matches!(JarqueBera::new(0), Err(Error::PeriodZero)));
+        assert!(matches!(
+            JarqueBera::new(3),
+            Err(Error::InvalidPeriod { .. })
+        ));
+        assert!(JarqueBera::new(4).is_ok());
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let jb = JarqueBera::new(50).unwrap();
+        assert_eq!(jb.period(), 50);
+        assert_eq!(jb.warmup_period(), 50);
+        assert_eq!(jb.name(), "JarqueBera");
+        assert!(!jb.is_ready());
+        assert_eq!(jb.value(), None);
+    }
+
+    #[test]
+    fn first_emission_at_warmup_period() {
+        let mut jb = JarqueBera::new(4).unwrap();
+        let out = jb.batch(&[1.0, 2.0, 3.0, 4.0, 5.0]);
+        for v in out.iter().take(3) {
+            assert!(v.is_none());
+        }
+        assert!(out[3].is_some());
+    }
+
+    #[test]
+    fn constant_window_is_zero() {
+        let mut jb = JarqueBera::new(8).unwrap();
+        let last = jb.batch(&[5.0; 12]).into_iter().flatten().last().unwrap();
+        assert_relative_eq!(last, 0.0, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn output_is_non_negative() {
+        let mut jb = JarqueBera::new(30).unwrap();
+        for v in jb
+            .batch(
+                &(0..200)
+                    .map(|i| (f64::from(i) * 0.3).sin() * 5.0)
+                    .collect::<Vec<_>>(),
+            )
+            .into_iter()
+            .flatten()
+        {
+            assert!(v >= 0.0, "JB must be non-negative, got {v}");
+        }
+    }
+
+    #[test]
+    fn skewed_window_exceeds_symmetric() {
+        // A symmetric window vs. one with a heavy outlier (high skew + kurtosis).
+        let symmetric: Vec<f64> = vec![-3.0, -1.0, 0.0, 1.0, 3.0, -2.0, 2.0, 0.0];
+        let skewed: Vec<f64> = vec![0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 20.0];
+        let jb_sym = JarqueBera::new(8)
+            .unwrap()
+            .batch(&symmetric)
+            .into_iter()
+            .flatten()
+            .last()
+            .unwrap();
+        let jb_skew = JarqueBera::new(8)
+            .unwrap()
+            .batch(&skewed)
+            .into_iter()
+            .flatten()
+            .last()
+            .unwrap();
+        assert!(
+            jb_skew > jb_sym,
+            "skewed ({jb_skew}) should exceed symmetric ({jb_sym})"
+        );
+    }
+
+    #[test]
+    fn ignores_non_finite() {
+        let mut jb = JarqueBera::new(4).unwrap();
+        let ready = jb
+            .batch(&[1.0, 2.0, 3.0, 5.0])
+            .into_iter()
+            .flatten()
+            .last()
+            .unwrap();
+        assert_eq!(jb.update(f64::NAN), Some(ready));
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut jb = JarqueBera::new(4).unwrap();
+        jb.batch(&[1.0, 2.0, 3.0, 5.0]);
+        assert!(jb.is_ready());
+        jb.reset();
+        assert!(!jb.is_ready());
+        assert_eq!(jb.value(), None);
+        assert_eq!(jb.update(1.0), None);
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let xs: Vec<f64> = (0..120)
+            .map(|i| (f64::from(i) * 0.25).sin() * 9.0)
+            .collect();
+        let batch = JarqueBera::new(30).unwrap().batch(&xs);
+        let mut b = JarqueBera::new(30).unwrap();
+        let streamed: Vec<_> = xs.iter().map(|x| b.update(*x)).collect();
+        assert_eq!(batch, streamed);
+    }
+}
@@ -0,0 +1,291 @@
+//! Jump Indicator — detects return outliers relative to trailing volatility.
+
+use std::collections::VecDeque;
+
+use crate::error::{Error, Result};
+use crate::traits::Indicator;
+
+/// Jump Indicator — a discrete `{−1, 0, +1}` flag for whether the current log
+/// return is an outlier relative to the trailing volatility of returns.
+///
+/// ```text
+/// rₜ   = ln(priceₜ / priceₜ₋₁)
+/// μ, σ = sample mean and stddev of the `period` returns *before* rₜ (trailing)
+/// flag = +1 if rₜ − μ >  threshold · σ
+///        −1 if rₜ − μ < −threshold · σ
+///         0 otherwise
+/// ```
+///
+/// The baseline is the trailing return distribution and **excludes** the current
+/// return, so a genuine jump cannot inflate the band it is tested against.
+/// Measuring the deviation from the trailing mean `μ` (not the raw return) means
+/// a steady drift is *not* flagged — only moves that are large relative to the
+/// recent return distribution count. `+1` marks an up jump, `−1` a down jump,
+/// and `0` an ordinary move. When the trailing window has zero dispersion
+/// (`σ = 0`, e.g. a perfectly constant drift) there is no defined baseline and
+/// the indicator returns `0` rather than flagging every move.
+///
+/// This is the generic, threshold-tunable detector; downstream models keep any
+/// regime-specific sensitivity by choosing `threshold`. Non-finite and
+/// non-positive prices are ignored (the log return is undefined): the tick is
+/// dropped and the last value returned.
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Indicator, JumpIndicator};
+///
+/// let mut indicator = JumpIndicator::new(20, 3.0).unwrap();
+/// let mut last = None;
+/// for i in 0..40 {
+///     last = indicator.update(100.0 + (f64::from(i) * 0.5).sin());
+/// }
+/// // A calm sinusoid produces no jumps.
+/// assert_eq!(last, Some(0.0));
+/// ```
+#[derive(Debug, Clone)]
+pub struct JumpIndicator {
+    period: usize,
+    threshold: f64,
+    prev_price: Option<f64>,
+    /// Trailing window of the `period` returns preceding the current one.
+    window: VecDeque<f64>,
+    sum: f64,
+    sum_sq: f64,
+    last: Option<f64>,
+}
+
+impl JumpIndicator {
+    /// Construct a new Jump Indicator.
+    ///
+    /// `threshold` is the number of trailing standard deviations a return must
+    /// exceed to be flagged.
+    ///
+    /// # Errors
+    /// Returns [`Error::InvalidPeriod`] if `period < 2` (the sample standard
+    /// deviation needs at least two returns), or [`Error::InvalidParameter`] if
+    /// `threshold` is not finite and positive.
+    pub fn new(period: usize, threshold: f64) -> Result<Self> {
+        if period < 2 {
+            return Err(Error::InvalidPeriod {
+                message: "jump indicator needs period >= 2",
+            });
+        }
+        if !threshold.is_finite() || threshold <= 0.0 {
+            return Err(Error::InvalidParameter {
+                message: "jump indicator threshold must be finite and positive",
+            });
+        }
+        Ok(Self {
+            period,
+            threshold,
+            prev_price: None,
+            window: VecDeque::with_capacity(period),
+            sum: 0.0,
+            sum_sq: 0.0,
+            last: None,
+        })
+    }
+
+    /// Configured `(period, threshold)`.
+    pub const fn params(&self) -> (usize, f64) {
+        (self.period, self.threshold)
+    }
+}
+
+impl Indicator for JumpIndicator {
+    type Input = f64;
+    type Output = f64;
+
+    fn update(&mut self, input: f64) -> Option<f64> {
+        if !input.is_finite() || input <= 0.0 {
+            return self.last;
+        }
+        let Some(prev) = self.prev_price else {
+            self.prev_price = Some(input);
+            return None;
+        };
+        self.prev_price = Some(input);
+        let r = (input / prev).ln();
+        if self.window.len() < self.period {
+            // Still filling the trailing window; no baseline yet.
+            self.window.push_back(r);
+            self.sum += r;
+            self.sum_sq += r * r;
+            return None;
+        }
+        // Trailing window is full: classify `r` against the volatility of the
+        // `period` returns that precede it.
+        let n = self.period as f64;
+        let mean = self.sum / n;
+        let var = ((self.sum_sq - n * mean * mean) / (n - 1.0)).max(0.0);
+        let sd = var.sqrt();
+        let deviation = r - mean;
+        let label = if sd == 0.0 {
+            0.0
+        } else if deviation > self.threshold * sd {
+            1.0
+        } else if deviation < -self.threshold * sd {
+            -1.0
+        } else {
+            0.0
+        };
+        // Slide the trailing window forward to include `r`.
+        let old = self.window.pop_front().expect("window is non-empty");
+        self.sum -= old;
+        self.sum_sq -= old * old;
+        self.window.push_back(r);
+        self.sum += r;
+        self.sum_sq += r * r;
+        self.last = Some(label);
+        Some(label)
+    }
+
+    fn reset(&mut self) {
+        self.prev_price = None;
+        self.window.clear();
+        self.sum = 0.0;
+        self.sum_sq = 0.0;
+        self.last = None;
+    }
+
+    fn warmup_period(&self) -> usize {
+        // One price seeds `prev`, `period` returns fill the trailing window,
+        // then the next return is the first one classified.
+        self.period + 2
+    }
+
+    fn is_ready(&self) -> bool {
+        self.last.is_some()
+    }
+
+    fn name(&self) -> &'static str {
+        "JumpIndicator"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+
+    #[test]
+    fn rejects_bad_params() {
+        assert!(matches!(
+            JumpIndicator::new(1, 3.0),
+            Err(Error::InvalidPeriod { .. })
+        ));
+        assert!(matches!(
+            JumpIndicator::new(20, 0.0),
+            Err(Error::InvalidParameter { .. })
+        ));
+        assert!(matches!(
+            JumpIndicator::new(20, f64::NAN),
+            Err(Error::InvalidParameter { .. })
+        ));
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let ji = JumpIndicator::new(20, 3.0).unwrap();
+        assert_eq!(ji.params(), (20, 3.0));
+        assert_eq!(ji.warmup_period(), 22);
+        assert_eq!(ji.name(), "JumpIndicator");
+        assert!(!ji.is_ready());
+    }
+
+    #[test]
+    fn detects_upward_jump() {
+        let mut ji = JumpIndicator::new(10, 3.0).unwrap();
+        // Calm oscillating warmup (small, varied returns), then a +20% spike.
+        let mut prices: Vec<f64> = (0..20)
+            .map(|i| 100.0 + (f64::from(i) * 0.7).sin() * 0.2)
+            .collect();
+        let last_calm = *prices.last().unwrap();
+        prices.push(last_calm * 1.2);
+        let out = ji.batch(&prices);
+        assert_eq!(out.last().copied().flatten(), Some(1.0));
+    }
+
+    #[test]
+    fn detects_downward_jump() {
+        let mut ji = JumpIndicator::new(10, 3.0).unwrap();
+        let mut prices: Vec<f64> = (0..20)
+            .map(|i| 100.0 + (f64::from(i) * 0.7).sin() * 0.2)
+            .collect();
+        let last_calm = *prices.last().unwrap();
+        prices.push(last_calm * 0.8);
+        let out = ji.batch(&prices);
+        assert_eq!(out.last().copied().flatten(), Some(-1.0));
+    }
+
+    #[test]
+    fn calm_series_has_no_jumps() {
+        let mut ji = JumpIndicator::new(20, 3.0).unwrap();
+        let prices: Vec<f64> = (0..80)
+            .map(|i| 100.0 + (f64::from(i) * 0.5).sin())
+            .collect();
+        for v in ji.batch(&prices).into_iter().flatten() {
+            assert_eq!(v, 0.0);
+        }
+    }
+
+    #[test]
+    fn zero_trailing_volatility_returns_zero() {
+        // A constant price has exactly-zero returns => zero trailing dispersion
+        // => no defined baseline => label 0. (Pins the `sd == 0` branch with an
+        // exact-zero series; a geometric drift is conceptually zero-vol too but
+        // floating-point rounding of the log returns leaves ~1e-16 noise.)
+        let mut ji = JumpIndicator::new(10, 3.0).unwrap();
+        for v in ji.batch(&[100.0; 30]).into_iter().flatten() {
+            assert_eq!(v, 0.0);
+        }
+    }
+
+    #[test]
+    fn steady_drift_is_not_flagged() {
+        // A near-constant positive drift (small, equal-ish returns) must not be
+        // flagged: the deviation from the trailing mean stays well inside the
+        // band even though the raw return is non-zero every bar.
+        let mut ji = JumpIndicator::new(10, 3.0).unwrap();
+        let prices: Vec<f64> = (0..40).map(|i| 100.0 + f64::from(i) * 0.5).collect();
+        for v in ji.batch(&prices).into_iter().flatten() {
+            assert_eq!(v, 0.0);
+        }
+    }
+
+    #[test]
+    fn ignores_non_finite_and_non_positive() {
+        let mut ji = JumpIndicator::new(5, 3.0).unwrap();
+        let prices: Vec<f64> = (0..20)
+            .map(|i| 100.0 + (f64::from(i) * 0.6).sin())
+            .collect();
+        let out = ji.batch(&prices);
+        let last = *out.last().unwrap();
+        assert!(last.is_some());
+        assert_eq!(ji.update(f64::NAN), last);
+        assert_eq!(ji.update(-1.0), last);
+        assert_eq!(ji.update(0.0), last);
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut ji = JumpIndicator::new(5, 3.0).unwrap();
+        ji.batch(&(1..=20).map(f64::from).collect::<Vec<_>>());
+        assert!(ji.is_ready());
+        ji.reset();
+        assert!(!ji.is_ready());
+        assert_eq!(ji.update(1.0), None);
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let prices: Vec<f64> = (1..=120)
+            .map(|i| 100.0 + (f64::from(i) * 0.25).sin() * 3.0)
+            .collect();
+        let batch = JumpIndicator::new(20, 3.0).unwrap().batch(&prices);
+        let mut b = JumpIndicator::new(20, 3.0).unwrap();
+        let streamed: Vec<_> = prices.iter().map(|p| b.update(*p)).collect();
+        assert_eq!(batch, streamed);
+    }
+}
@@ -0,0 +1,341 @@
+//! Kase `DevStop` — a volatility trailing stop on the standard deviation of the
+//! two-bar true range.
+
+use std::collections::VecDeque;
+
+use crate::error::{Error, Result};
+use crate::ohlcv::Candle;
+use crate::traits::Indicator;
+
+/// Output of [`KaseDevStop`]: the active trailing-stop level and the trend
+/// direction it protects.
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub struct KaseDevStopOutput {
+    /// The `DevStop` level — below price in an uptrend, above price in a downtrend.
+    pub value: f64,
+    /// Trend direction: `+1.0` long (stop below price), `-1.0` short.
+    pub direction: f64,
+}
+
+/// Sample standard deviation from a running `(sum, sum_of_squares, count)`.
+fn sample_stddev(sum: f64, sum_sq: f64, count: usize) -> f64 {
+    let n = count as f64;
+    let mean = sum / n;
+    (((sum_sq - n * mean * mean) / (n - 1.0)).max(0.0)).sqrt()
+}
+
+/// Kase `DevStop` — Cynthia Kase's volatility stop, built on the **standard
+/// deviation of the two-bar true range** rather than a single-bar ATR.
+///
+/// ```text
+/// DTR_t = max(high_t, high_{t−1}) − min(low_t, low_{t−1})   (two-bar range)
+/// band  = mean(DTR, period) + dev · stddev(DTR, period)
+/// long  stop = ratchet_up(  highest_high_since_flip − band )
+/// short stop = ratchet_down( lowest_low_since_flip  + band )
+/// ```
+///
+/// Kase observed that range expansion is better captured by a two-bar range than
+/// a one-bar one, and that subtracting a *standard-deviation* band (not a fixed
+/// ATR multiple) adapts the stop to changing volatility. The stop trails the
+/// extreme reached since the last reversal — ratcheting only in the trend's favour
+/// — and flips sides when price closes through it. `dev` selects which `DevStop`
+/// line to follow (`1`, `2` or `3` standard deviations are Kase's warning lines).
+///
+/// The first bar seeds the prior candle; the next `period` two-bar ranges seed the
+/// mean and standard deviation, so the first stop lands after `period + 1` inputs.
+/// Each `update` is O(1).
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Candle, Indicator, KaseDevStop};
+///
+/// let mut indicator = KaseDevStop::new(30, 1.0).unwrap();
+/// let mut last = None;
+/// for i in 0..80 {
+///     let base = 100.0 + f64::from(i);
+///     let c = Candle::new(base, base + 2.0, base - 2.0, base + 1.0, 1_000.0, 0).unwrap();
+///     last = indicator.update(c);
+/// }
+/// assert!(last.is_some());
+/// ```
+#[derive(Debug, Clone)]
+pub struct KaseDevStop {
+    period: usize,
+    dev: f64,
+    prev: Option<Candle>,
+    window: VecDeque<f64>,
+    sum: f64,
+    sum_sq: f64,
+    direction: f64,
+    extreme: f64,
+    stop: f64,
+    last: Option<KaseDevStopOutput>,
+}
+
+impl KaseDevStop {
+    /// Construct a Kase `DevStop` with the given lookback `period` and
+    /// standard-deviation multiplier `dev`.
+    ///
+    /// # Errors
+    ///
+    /// Returns [`Error::InvalidPeriod`] if `period < 2` (a standard deviation
+    /// needs at least two samples) and [`Error::NonPositiveMultiplier`] if `dev`
+    /// is not finite and positive.
+    pub fn new(period: usize, dev: f64) -> Result<Self> {
+        if period < 2 {
+            return Err(Error::InvalidPeriod {
+                message: "Kase DevStop period must be >= 2",
+            });
+        }
+        if !dev.is_finite() || dev <= 0.0 {
+            return Err(Error::NonPositiveMultiplier);
+        }
+        Ok(Self {
+            period,
+            dev,
+            prev: None,
+            window: VecDeque::with_capacity(period),
+            sum: 0.0,
+            sum_sq: 0.0,
+            direction: 0.0,
+            extreme: 0.0,
+            stop: 0.0,
+            last: None,
+        })
+    }
+
+    /// Configured `(period, dev)`.
+    pub const fn params(&self) -> (usize, f64) {
+        (self.period, self.dev)
+    }
+
+    /// Current value if available.
+    pub const fn value(&self) -> Option<KaseDevStopOutput> {
+        self.last
+    }
+}
+
+impl Indicator for KaseDevStop {
+    type Input = Candle;
+    type Output = KaseDevStopOutput;
+
+    fn update(&mut self, candle: Candle) -> Option<KaseDevStopOutput> {
+        let Some(prev) = self.prev else {
+            self.prev = Some(candle);
+            return None;
+        };
+        let dtr = candle.high.max(prev.high) - candle.low.min(prev.low);
+        self.prev = Some(candle);
+
+        if self.window.len() == self.period {
+            let old = self.window.pop_front().expect("non-empty");
+            self.sum -= old;
+            self.sum_sq -= old * old;
+        }
+        self.window.push_back(dtr);
+        self.sum += dtr;
+        self.sum_sq += dtr * dtr;
+        if self.window.len() < self.period {
+            return None;
+        }
+        let mean = self.sum / self.period as f64;
+        let band = mean + self.dev * sample_stddev(self.sum, self.sum_sq, self.period);
+
+        if self.direction == 0.0 {
+            // Seed the trend as long off the first fully-warmed bar.
+            self.direction = 1.0;
+            self.extreme = candle.high;
+            self.stop = candle.high - band;
+        } else if self.direction > 0.0 {
+            self.extreme = self.extreme.max(candle.high);
+            let raw = self.extreme - band;
+            self.stop = self.stop.max(raw);
+            if candle.close < self.stop {
+                self.direction = -1.0;
+                self.extreme = candle.low;
+                self.stop = candle.low + band;
+            }
+        } else {
+            self.extreme = self.extreme.min(candle.low);
+            let raw = self.extreme + band;
+            self.stop = self.stop.min(raw);
+            if candle.close > self.stop {
+                self.direction = 1.0;
+                self.extreme = candle.high;
+                self.stop = candle.high - band;
+            }
+        }
+
+        let out = KaseDevStopOutput {
+            value: self.stop,
+            direction: self.direction,
+        };
+        self.last = Some(out);
+        Some(out)
+    }
+
+    fn reset(&mut self) {
+        self.prev = None;
+        self.window.clear();
+        self.sum = 0.0;
+        self.sum_sq = 0.0;
+        self.direction = 0.0;
+        self.extreme = 0.0;
+        self.stop = 0.0;
+        self.last = None;
+    }
+
+    fn warmup_period(&self) -> usize {
+        self.period + 1
+    }
+
+    fn is_ready(&self) -> bool {
+        self.last.is_some()
+    }
+
+    fn name(&self) -> &'static str {
+        "KaseDevStop"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+
+    fn c(high: f64, low: f64, close: f64) -> Candle {
+        Candle::new_unchecked(f64::midpoint(high, low), high, low, close, 1_000.0, 0)
+    }
+
+    #[test]
+    fn rejects_invalid_params() {
+        assert!(matches!(
+            KaseDevStop::new(1, 1.0),
+            Err(Error::InvalidPeriod { .. })
+        ));
+        assert!(matches!(
+            KaseDevStop::new(30, 0.0),
+            Err(Error::NonPositiveMultiplier)
+        ));
+        assert!(matches!(
+            KaseDevStop::new(30, -1.0),
+            Err(Error::NonPositiveMultiplier)
+        ));
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let k = KaseDevStop::new(30, 1.0).unwrap();
+        assert_eq!(k.params(), (30, 1.0));
+        assert_eq!(k.warmup_period(), 31);
+        assert_eq!(k.name(), "KaseDevStop");
+        assert!(!k.is_ready());
+        assert_eq!(k.value(), None);
+    }
+
+    #[test]
+    fn first_emission_at_warmup_period() {
+        let mut k = KaseDevStop::new(3, 1.0).unwrap();
+        let candles: Vec<Candle> = (0..8)
+            .map(|i| {
+                let base = 100.0 + f64::from(i);
+                c(base + 1.0, base - 1.0, base)
+            })
+            .collect();
+        let out = k.batch(&candles);
+        let warmup = k.warmup_period(); // 4
+        assert_eq!(warmup, 4);
+        for v in out.iter().take(warmup - 1) {
+            assert!(v.is_none());
+        }
+        assert!(out[warmup - 1].is_some());
+    }
+
+    #[test]
+    fn uptrend_keeps_stop_below_price() {
+        let mut k = KaseDevStop::new(5, 1.0).unwrap();
+        let candles: Vec<Candle> = (0..60)
+            .map(|i| {
+                let base = 100.0 + 2.0 * f64::from(i);
+                c(base + 1.0, base - 1.0, base + 0.5)
+            })
+            .collect();
+        for (o, candle) in k.batch(&candles).into_iter().zip(candles.iter()) {
+            if let Some(o) = o {
+                assert_eq!(o.direction, 1.0, "pure uptrend stays long");
+                assert!(o.value < candle.close, "stop below price");
+            }
+        }
+    }
+
+    #[test]
+    fn stop_ratchets_up_in_uptrend() {
+        let mut k = KaseDevStop::new(5, 1.0).unwrap();
+        let candles: Vec<Candle> = (0..60)
+            .map(|i| {
+                let base = 100.0 + 2.0 * f64::from(i);
+                c(base + 1.0, base - 1.0, base + 0.5)
+            })
+            .collect();
+        let mut prev = f64::NEG_INFINITY;
+        for o in k.batch(&candles).into_iter().flatten() {
+            assert!(o.value >= prev, "long stop must not fall");
+            prev = o.value;
+        }
+    }
+
+    #[test]
+    fn flips_on_reversal() {
+        let mut candles: Vec<Candle> = (0..40)
+            .map(|i| {
+                let base = 100.0 + f64::from(i);
+                c(base + 1.0, base - 1.0, base + 0.5)
+            })
+            .collect();
+        candles.extend((0..40).map(|i| {
+            let base = 140.0 - f64::from(i);
+            c(base + 1.0, base - 1.0, base - 0.5)
+        }));
+        let mut k = KaseDevStop::new(5, 1.0).unwrap();
+        let dirs: Vec<f64> = k
+            .batch(&candles)
+            .into_iter()
+            .flatten()
+            .map(|o| o.direction)
+            .collect();
+        assert!(dirs.iter().any(|&d| d > 0.0));
+        assert!(dirs.iter().any(|&d| d < 0.0));
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut k = KaseDevStop::new(5, 1.0).unwrap();
+        let candles: Vec<Candle> = (0..40)
+            .map(|i| {
+                let base = 100.0 + f64::from(i);
+                c(base + 1.0, base - 1.0, base + 0.5)
+            })
+            .collect();
+        k.batch(&candles);
+        assert!(k.is_ready());
+        k.reset();
+        assert!(!k.is_ready());
+        assert_eq!(k.value(), None);
+        assert_eq!(k.update(candles[0]), None);
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let candles: Vec<Candle> = (0..120)
+            .map(|i| {
+                let base = 100.0 + (f64::from(i) * 0.25).sin() * 9.0;
+                c(base + 2.0, base - 1.5, base + 0.5)
+            })
+            .collect();
+        let batch = KaseDevStop::new(20, 2.0).unwrap().batch(&candles);
+        let mut b = KaseDevStop::new(20, 2.0).unwrap();
+        let streamed: Vec<_> = candles.iter().map(|c| b.update(*c)).collect();
+        assert_eq!(batch, streamed);
+    }
+}
@@ -0,0 +1,234 @@
+//! Kase Permission Stochastic — a double-smoothed stochastic used as a
+//! trade-permission filter.
+
+use std::collections::VecDeque;
+
+use crate::error::{Error, Result};
+use crate::indicators::ema::Ema;
+use crate::ohlcv::Candle;
+use crate::traits::Indicator;
+
+/// Kase Permission Stochastic output: a fast and a slow line.
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub struct KasePermissionStochasticOutput {
+    /// Fast line: EMA of the raw `%K` over the smoothing period.
+    pub fast: f64,
+    /// Slow line: EMA of the fast line over the smoothing period.
+    pub slow: f64,
+}
+
+/// Cynthia Kase's Permission Stochastic: a stochastic oscillator smoothed twice,
+/// whose fast/slow relationship grants or denies "permission" to trade in the
+/// direction of a higher-timeframe signal.
+///
+/// ```text
+/// raw%K = 100 * (close - LL) / (HH - LL)     over `length` (50 when HH == LL)
+/// fast  = EMA(raw%K, smooth)
+/// slow  = EMA(fast,  smooth)
+/// ```
+///
+/// The raw stochastic is the usual `%K`, then an EMA produces the *fast* line
+/// and a second EMA of that produces the *slow* line. Kase uses the pair as a
+/// gate: a fast line above the slow line (and rising) gives permission for
+/// longs, the reverse for shorts. When the lookback window is perfectly flat
+/// (`HH == LL`), the raw stochastic is undefined and defaults to the neutral
+/// `50`.
+///
+/// Reference: Cynthia Kase, *Trading with the Odds*, 1996.
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Candle, Indicator, KasePermissionStochastic};
+///
+/// let mut indicator = KasePermissionStochastic::new(9, 3).unwrap();
+/// let mut last = None;
+/// for i in 0..40 {
+///     let base = 100.0 + f64::from(i);
+///     let candle =
+///         Candle::new(base, base + 2.0, base - 2.0, base + 1.0, 1.0, i64::from(i)).unwrap();
+///     last = indicator.update(candle);
+/// }
+/// assert!(last.is_some());
+/// ```
+#[derive(Debug, Clone)]
+pub struct KasePermissionStochastic {
+    length: usize,
+    smooth: usize,
+    window: VecDeque<(f64, f64)>,
+    fast_ema: Ema,
+    slow_ema: Ema,
+}
+
+impl KasePermissionStochastic {
+    /// Construct with the stochastic `length` and the EMA `smooth` period
+    /// applied twice.
+    ///
+    /// # Errors
+    ///
+    /// Returns [`Error::PeriodZero`] if `length == 0` or `smooth == 0`.
+    pub fn new(length: usize, smooth: usize) -> Result<Self> {
+        if length == 0 {
+            return Err(Error::PeriodZero);
+        }
+        Ok(Self {
+            length,
+            smooth,
+            window: VecDeque::with_capacity(length),
+            fast_ema: Ema::new(smooth)?,
+            slow_ema: Ema::new(smooth)?,
+        })
+    }
+
+    /// Cynthia Kase's classic parameters: `length = 9`, `smooth = 3`.
+    pub fn classic() -> Self {
+        Self::new(9, 3).expect("classic Kase Permission Stochastic parameters are valid")
+    }
+
+    /// Configured `(length, smooth)`.
+    pub const fn periods(&self) -> (usize, usize) {
+        (self.length, self.smooth)
+    }
+}
+
+impl Indicator for KasePermissionStochastic {
+    type Input = Candle;
+    type Output = KasePermissionStochasticOutput;
+
+    fn update(&mut self, candle: Candle) -> Option<KasePermissionStochasticOutput> {
+        self.window.push_back((candle.high, candle.low));
+        if self.window.len() > self.length {
+            self.window.pop_front();
+        }
+        if self.window.len() < self.length {
+            return None;
+        }
+
+        let highest = self.window.iter().map(|w| w.0).fold(f64::MIN, f64::max);
+        let lowest = self.window.iter().map(|w| w.1).fold(f64::MAX, f64::min);
+        let raw_k = if highest > lowest {
+            100.0 * (candle.close - lowest) / (highest - lowest)
+        } else {
+            50.0
+        };
+
+        let fast = self.fast_ema.update(raw_k)?;
+        let slow = self.slow_ema.update(fast)?;
+        Some(KasePermissionStochasticOutput { fast, slow })
+    }
+
+    fn reset(&mut self) {
+        self.window.clear();
+        self.fast_ema.reset();
+        self.slow_ema.reset();
+    }
+
+    fn warmup_period(&self) -> usize {
+        // raw%K ready after `length` bars; each EMA seeds over `smooth` values.
+        self.length + 2 * self.smooth - 2
+    }
+
+    fn is_ready(&self) -> bool {
+        self.slow_ema.is_ready()
+    }
+
+    fn name(&self) -> &'static str {
+        "KasePermissionStochastic"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    fn candle(high: f64, low: f64, close: f64, ts: i64) -> Candle {
+        Candle::new(f64::midpoint(high, low), high, low, close, 1.0, ts).unwrap()
+    }
+
+    #[test]
+    fn rejects_zero_period() {
+        assert!(matches!(
+            KasePermissionStochastic::new(0, 3),
+            Err(Error::PeriodZero)
+        ));
+        assert!(matches!(
+            KasePermissionStochastic::new(9, 0),
+            Err(Error::PeriodZero)
+        ));
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let k = KasePermissionStochastic::classic();
+        assert_eq!(k.periods(), (9, 3));
+        // 9 + 2*3 - 2 = 13.
+        assert_eq!(k.warmup_period(), 13);
+        assert_eq!(k.name(), "KasePermissionStochastic");
+        assert!(!k.is_ready());
+    }
+
+    #[test]
+    fn warmup_emits_at_expected_bar() {
+        let mut k = KasePermissionStochastic::new(3, 2).unwrap();
+        // warmup = 3 + 2*2 - 2 = 5 -> first value at input 5 (index 4).
+        let candles: Vec<Candle> = (0..8).map(|i| candle(11.0, 9.0, 10.5, i)).collect();
+        let out = k.batch(&candles);
+        assert!(out[3].is_none());
+        assert!(out[4].is_some());
+    }
+
+    #[test]
+    fn top_of_range_is_high() {
+        // Close pinned at the top of a rising range -> raw%K near 100, both
+        // smoothed lines high.
+        let mut k = KasePermissionStochastic::new(5, 3).unwrap();
+        let candles: Vec<Candle> = (0_i64..40)
+            .map(|i| {
+                let base = 100.0 + i as f64;
+                candle(base + 2.0, base - 2.0, base + 2.0, i)
+            })
+            .collect();
+        let last = k.batch(&candles).last().unwrap().unwrap();
+        assert!(last.fast > 80.0, "fast {} should be high", last.fast);
+        assert!(last.slow > 80.0, "slow {} should be high", last.slow);
+    }
+
+    #[test]
+    fn flat_window_defaults_to_neutral() {
+        // Constant high/low/close -> HH == LL -> raw%K defaults to 50, so both
+        // EMAs converge to 50.
+        let mut k = KasePermissionStochastic::new(4, 2).unwrap();
+        let candles: Vec<Candle> = (0..20).map(|i| candle(10.0, 10.0, 10.0, i)).collect();
+        let last = k.batch(&candles).last().unwrap().unwrap();
+        assert_relative_eq!(last.fast, 50.0, epsilon = 1e-9);
+        assert_relative_eq!(last.slow, 50.0, epsilon = 1e-9);
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut k = KasePermissionStochastic::classic();
+        let candles: Vec<Candle> = (0..40).map(|i| candle(11.0, 9.0, 10.5, i)).collect();
+        k.batch(&candles);
+        assert!(k.is_ready());
+        k.reset();
+        assert!(!k.is_ready());
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let candles: Vec<Candle> = (0..80_i64)
+            .map(|i| {
+                let base = 100.0 + (i as f64 * 0.2).sin() * 5.0;
+                candle(base + 2.0, base - 2.0, base + (i as f64 * 0.3).cos(), i)
+            })
+            .collect();
+        let mut a = KasePermissionStochastic::classic();
+        let mut b = KasePermissionStochastic::classic();
+        assert_eq!(
+            a.batch(&candles),
+            candles.iter().map(|c| b.update(*c)).collect::<Vec<_>>()
+        );
+    }
+}
@@ -0,0 +1,296 @@
+//! Kendall's tau-b — rank correlation by concordant vs. discordant pairs.
+
+use std::collections::VecDeque;
+
+use crate::error::{Error, Result};
+use crate::traits::Indicator;
+
+/// `+1` / `0` / `-1` sign of `a − b`.
+fn sign(a: f64, b: f64) -> i32 {
+    if a > b {
+        1
+    } else if a < b {
+        -1
+    } else {
+        0
+    }
+}
+
+/// Kendall's tau-b — a rank correlation between two synchronised series based on
+/// the balance of **concordant** and **discordant** pairs, with a tie correction.
+///
+/// ```text
+/// over all pairs (i < j) in the window:
+///   concordant if (x_j − x_i) and (y_j − y_i) share a sign
+///   discordant if they have opposite signs
+///   tie_x / tie_y if the respective difference is zero
+/// n0  = N(N−1)/2
+/// tau_b = (n_concordant − n_discordant) / sqrt((n0 − tie_x)(n0 − tie_y))
+/// ```
+///
+/// Where [`PearsonCorrelation`](crate::PearsonCorrelation) measures *linear*
+/// co-movement and [`SpearmanCorrelation`](crate::SpearmanCorrelation) correlates
+/// ranks via their differences, Kendall's tau counts how often the two series move
+/// the **same direction** between every pair of observations. It is the most
+/// robust of the three to outliers and to non-linear-but-monotonic
+/// relationships, and the tau-b form corrects for ties so repeated values do not
+/// bias it. The output is in `[−1, +1]`: `+1` perfectly concordant, `−1`
+/// perfectly discordant, `0` no monotonic association.
+///
+/// The window holds the last `period` pairs and is recomputed each bar in
+/// O(`period²`). A window with no untied pairs on one side returns `0`. The first
+/// value lands after `period` inputs.
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Indicator, KendallTau};
+///
+/// let mut indicator = KendallTau::new(20).unwrap();
+/// let mut last = None;
+/// for i in 0..40 {
+///     let x = f64::from(i);
+///     last = indicator.update((x, 2.0 * x)); // perfectly concordant
+/// }
+/// assert!((last.unwrap() - 1.0).abs() < 1e-9);
+/// ```
+#[derive(Debug, Clone)]
+pub struct KendallTau {
+    period: usize,
+    window: VecDeque<(f64, f64)>,
+    last: Option<f64>,
+}
+
+impl KendallTau {
+    /// Construct a rolling Kendall's tau-b over `period` pairs.
+    ///
+    /// # Errors
+    ///
+    /// Returns [`Error::InvalidPeriod`] if `period < 2` (a correlation needs at
+    /// least two pairs).
+    pub fn new(period: usize) -> Result<Self> {
+        if period < 2 {
+            return Err(Error::InvalidPeriod {
+                message: "Kendall tau needs period >= 2",
+            });
+        }
+        Ok(Self {
+            period,
+            window: VecDeque::with_capacity(period),
+            last: None,
+        })
+    }
+
+    /// Configured window of pairs.
+    pub const fn period(&self) -> usize {
+        self.period
+    }
+
+    /// Current value if available.
+    pub const fn value(&self) -> Option<f64> {
+        self.last
+    }
+
+    fn compute(&self) -> f64 {
+        let pairs: Vec<(f64, f64)> = self.window.iter().copied().collect();
+        let len = pairs.len();
+        let mut concordant: i64 = 0;
+        let mut discordant: i64 = 0;
+        let mut tie_x: i64 = 0;
+        let mut tie_y: i64 = 0;
+        for i in 0..len {
+            for j in (i + 1)..len {
+                let sx = sign(pairs[j].0, pairs[i].0);
+                let sy = sign(pairs[j].1, pairs[i].1);
+                if sx == 0 {
+                    tie_x += 1;
+                }
+                if sy == 0 {
+                    tie_y += 1;
+                }
+                let prod = sx * sy;
+                if prod > 0 {
+                    concordant += 1;
+                } else if prod < 0 {
+                    discordant += 1;
+                }
+            }
+        }
+        let n0 = (len * (len - 1) / 2) as f64;
+        let denom = ((n0 - tie_x as f64) * (n0 - tie_y as f64)).sqrt();
+        if denom == 0.0 {
+            return 0.0;
+        }
+        ((concordant - discordant) as f64 / denom).clamp(-1.0, 1.0)
+    }
+}
+
+impl Indicator for KendallTau {
+    type Input = (f64, f64);
+    type Output = f64;
+
+    fn update(&mut self, input: (f64, f64)) -> Option<f64> {
+        if self.window.len() == self.period {
+            self.window.pop_front();
+        }
+        self.window.push_back(input);
+        if self.window.len() < self.period {
+            return None;
+        }
+        let out = self.compute();
+        self.last = Some(out);
+        Some(out)
+    }
+
+    fn reset(&mut self) {
+        self.window.clear();
+        self.last = None;
+    }
+
+    fn warmup_period(&self) -> usize {
+        self.period
+    }
+
+    fn is_ready(&self) -> bool {
+        self.last.is_some()
+    }
+
+    fn name(&self) -> &'static str {
+        "KendallTau"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    #[test]
+    fn rejects_period_below_two() {
+        assert!(matches!(
+            KendallTau::new(1),
+            Err(Error::InvalidPeriod { .. })
+        ));
+        assert!(KendallTau::new(2).is_ok());
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let k = KendallTau::new(20).unwrap();
+        assert_eq!(k.period(), 20);
+        assert_eq!(k.warmup_period(), 20);
+        assert_eq!(k.name(), "KendallTau");
+        assert!(!k.is_ready());
+        assert_eq!(k.value(), None);
+    }
+
+    #[test]
+    fn first_emission_at_warmup_period() {
+        let mut k = KendallTau::new(4).unwrap();
+        let out = k.batch(&[(1.0, 1.0), (2.0, 2.0), (3.0, 3.0), (4.0, 4.0), (5.0, 5.0)]);
+        for v in out.iter().take(3) {
+            assert!(v.is_none());
+        }
+        assert!(out[3].is_some());
+    }
+
+    #[test]
+    fn monotone_increasing_is_one() {
+        let pairs: Vec<(f64, f64)> = (0..20)
+            .map(|i| (f64::from(i), 2.0 * f64::from(i) + 1.0))
+            .collect();
+        let last = KendallTau::new(10)
+            .unwrap()
+            .batch(&pairs)
+            .into_iter()
+            .flatten()
+            .last()
+            .unwrap();
+        assert_relative_eq!(last, 1.0, epsilon = 1e-9);
+    }
+
+    #[test]
+    fn monotone_decreasing_is_minus_one() {
+        let pairs: Vec<(f64, f64)> = (0..20)
+            .map(|i| (f64::from(i), -3.0 * f64::from(i)))
+            .collect();
+        let last = KendallTau::new(10)
+            .unwrap()
+            .batch(&pairs)
+            .into_iter()
+            .flatten()
+            .last()
+            .unwrap();
+        assert_relative_eq!(last, -1.0, epsilon = 1e-9);
+    }
+
+    #[test]
+    fn constant_channel_yields_zero() {
+        // y constant -> every y-difference is a tie -> denom 0 -> 0.
+        let pairs: Vec<(f64, f64)> = (0..20).map(|i| (f64::from(i), 7.0)).collect();
+        let last = KendallTau::new(8)
+            .unwrap()
+            .batch(&pairs)
+            .into_iter()
+            .flatten()
+            .last()
+            .unwrap();
+        assert_relative_eq!(last, 0.0, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn output_in_range() {
+        let pairs: Vec<(f64, f64)> = (0..80)
+            .map(|i| {
+                let t = f64::from(i);
+                (100.0 + t.sin() * 5.0, 50.0 + (t * 0.3).cos() * 3.0)
+            })
+            .collect();
+        for v in KendallTau::new(20)
+            .unwrap()
+            .batch(&pairs)
+            .into_iter()
+            .flatten()
+        {
+            assert!((-1.0..=1.0).contains(&v));
+        }
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut k = KendallTau::new(4).unwrap();
+        k.batch(&[(1.0, 1.0), (2.0, 2.0), (3.0, 3.0), (4.0, 4.0)]);
+        assert!(k.is_ready());
+        k.reset();
+        assert!(!k.is_ready());
+        assert_eq!(k.value(), None);
+        assert_eq!(k.update((1.0, 1.0)), None);
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let pairs: Vec<(f64, f64)> = (0..60)
+            .map(|i| {
+                let t = f64::from(i);
+                (t.sin(), (t * 0.5).cos())
+            })
+            .collect();
+        let batch = KendallTau::new(14).unwrap().batch(&pairs);
+        let mut b = KendallTau::new(14).unwrap();
+        let streamed: Vec<_> = pairs.iter().map(|p| b.update(*p)).collect();
+        assert_eq!(batch, streamed);
+    }
+
+    #[test]
+    fn ties_are_corrected() {
+        // Tied x values (points 0 and 1) and tied y values (points 1 and 2)
+        // exercise the tie_x / tie_y correction counters.
+        let mut k = KendallTau::new(4).unwrap();
+        assert_eq!(k.update((1.0, 1.0)), None);
+        assert_eq!(k.update((1.0, 2.0)), None);
+        assert_eq!(k.update((2.0, 2.0)), None);
+        let v = k.update((3.0, 3.0)).unwrap();
+        assert!((-1.0..=1.0).contains(&v), "got {v}");
+    }
+}
@@ -0,0 +1,218 @@
+//! Logarithmic Return over a fixed lag.
+
+use std::collections::VecDeque;
+
+use crate::error::{Error, Result};
+use crate::traits::Indicator;
+
+/// Logarithmic return over a `period`-bar lag: `ln(price_t / price_{t−period})`.
+///
+/// The natural-log analogue of [`Roc`](crate::Roc) (which reports the simple
+/// percentage change). Log returns are the canonical input for volatility and
+/// statistical models because they are additive across time — the log return
+/// over `k` bars equals the sum of the `k` one-bar log returns — and symmetric
+/// around zero (a `+x` move and the reverse `−x` move cancel exactly).
+///
+/// ```text
+/// r_t = ln(price_t / price_{t−period})
+/// ```
+///
+/// Non-finite and non-positive prices are ignored: the input is dropped, state
+/// is left untouched, and the last computed value is returned instead. The log
+/// of a non-positive price is undefined, so such ticks must not enter the
+/// window — mirroring [`HistoricalVolatility`](crate::HistoricalVolatility).
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Indicator, LogReturn};
+///
+/// let mut indicator = LogReturn::new(1).unwrap();
+/// indicator.update(100.0);
+/// // ln(110 / 100) ≈ 0.09531
+/// let r = indicator.update(110.0).unwrap();
+/// assert!((r - (110.0_f64 / 100.0).ln()).abs() < 1e-12);
+/// ```
+#[derive(Debug, Clone)]
+pub struct LogReturn {
+    period: usize,
+    window: VecDeque<f64>,
+    last: Option<f64>,
+}
+
+impl LogReturn {
+    /// Construct a new log-return indicator with the given lag.
+    ///
+    /// # Errors
+    /// Returns [`Error::PeriodZero`] if `period == 0`.
+    pub fn new(period: usize) -> Result<Self> {
+        if period == 0 {
+            return Err(Error::PeriodZero);
+        }
+        Ok(Self {
+            period,
+            window: VecDeque::with_capacity(period + 1),
+            last: None,
+        })
+    }
+
+    /// Configured lag.
+    pub const fn period(&self) -> usize {
+        self.period
+    }
+}
+
+impl Indicator for LogReturn {
+    type Input = f64;
+    type Output = f64;
+
+    fn update(&mut self, input: f64) -> Option<f64> {
+        // Non-finite or non-positive prices are ignored: `ln` of a non-positive
+        // price is undefined, so the tick must not enter the window. Return the
+        // last value and leave state untouched (SMA / EMA / HV convention).
+        if !input.is_finite() || input <= 0.0 {
+            return self.last;
+        }
+        if self.window.len() == self.period + 1 {
+            self.window.pop_front();
+        }
+        self.window.push_back(input);
+        if self.window.len() < self.period + 1 {
+            return None;
+        }
+        // `prev` was pushed through the same guard, so it is finite and > 0 and
+        // `(input / prev).ln()` is always well-defined.
+        let prev = *self.window.front().expect("non-empty");
+        let r = (input / prev).ln();
+        self.last = Some(r);
+        Some(r)
+    }
+
+    fn reset(&mut self) {
+        self.window.clear();
+        self.last = None;
+    }
+
+    fn warmup_period(&self) -> usize {
+        self.period + 1
+    }
+
+    fn is_ready(&self) -> bool {
+        self.window.len() == self.period + 1
+    }
+
+    fn name(&self) -> &'static str {
+        "LogReturn"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    #[test]
+    fn rejects_zero_period() {
+        assert!(matches!(LogReturn::new(0), Err(Error::PeriodZero)));
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let lr = LogReturn::new(5).unwrap();
+        assert_eq!(lr.period(), 5);
+        assert_eq!(lr.warmup_period(), 6);
+        assert_eq!(lr.name(), "LogReturn");
+        assert!(!lr.is_ready());
+    }
+
+    #[test]
+    fn known_value() {
+        // LogReturn(1): ln(110 / 100).
+        let mut lr = LogReturn::new(1).unwrap();
+        let out = lr.batch(&[100.0, 110.0]);
+        assert!(out[0].is_none());
+        assert_relative_eq!(out[1].unwrap(), (110.0_f64 / 100.0).ln(), epsilon = 1e-12);
+    }
+
+    #[test]
+    fn multi_bar_lag() {
+        // LogReturn(3): at index 3, ln(price_3 / price_0).
+        let mut lr = LogReturn::new(3).unwrap();
+        let out = lr.batch(&[100.0, 105.0, 108.0, 121.0]);
+        for v in out.iter().take(3) {
+            assert!(v.is_none());
+        }
+        assert_relative_eq!(out[3].unwrap(), (121.0_f64 / 100.0).ln(), epsilon = 1e-12);
+    }
+
+    #[test]
+    fn additive_across_time() {
+        // The 2-bar log return equals the sum of the two 1-bar log returns.
+        let prices = [50.0, 55.0, 60.5];
+        let mut lag2 = LogReturn::new(2).unwrap();
+        let two_bar = lag2.batch(&prices)[2].unwrap();
+        let mut lag1 = LogReturn::new(1).unwrap();
+        let ones = lag1.batch(&prices);
+        let sum = ones[1].unwrap() + ones[2].unwrap();
+        assert_relative_eq!(two_bar, sum, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn constant_series_yields_zero() {
+        let mut lr = LogReturn::new(4).unwrap();
+        for v in lr.batch(&[42.0; 20]).into_iter().flatten() {
+            assert_relative_eq!(v, 0.0, epsilon = 1e-12);
+        }
+    }
+
+    #[test]
+    fn ignores_non_finite_input() {
+        let mut lr = LogReturn::new(1).unwrap();
+        let out = lr.batch(&[100.0, 110.0]);
+        let ready = out[1].expect("ready after two inputs");
+        assert_eq!(lr.update(f64::NAN), Some(ready));
+        assert_eq!(lr.update(f64::INFINITY), Some(ready));
+        // Window untouched: the next finite price still references prev = 110.
+        assert_relative_eq!(
+            lr.update(121.0).unwrap(),
+            (121.0_f64 / 110.0).ln(),
+            epsilon = 1e-12
+        );
+    }
+
+    #[test]
+    fn skips_non_positive_prices() {
+        let mut lr = LogReturn::new(1).unwrap();
+        let out = lr.batch(&[100.0, 110.0]);
+        let baseline = out[1].expect("ready");
+        // A non-positive tick is ignored and the previous valid price is kept.
+        assert_eq!(lr.update(-5.0), Some(baseline));
+        assert_eq!(lr.update(0.0), Some(baseline));
+        let mut control = lr.clone();
+        let after = lr.update(121.0).expect("ready");
+        assert_eq!(control.update(121.0).expect("ready"), after);
+        assert_relative_eq!(after, (121.0_f64 / 110.0).ln(), epsilon = 1e-12);
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut lr = LogReturn::new(3).unwrap();
+        lr.batch(&[1.0, 2.0, 3.0, 4.0, 5.0]);
+        assert!(lr.is_ready());
+        lr.reset();
+        assert!(!lr.is_ready());
+        assert_eq!(lr.update(1.0), None);
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let prices: Vec<f64> = (1..=60)
+            .map(|i| 100.0 + (f64::from(i) * 0.3).sin() * 5.0)
+            .collect();
+        let batch = LogReturn::new(5).unwrap().batch(&prices);
+        let mut b = LogReturn::new(5).unwrap();
+        let streamed: Vec<_> = prices.iter().map(|p| b.update(*p)).collect();
+        assert_eq!(batch, streamed);
+    }
+}
@@ -86,6 +86,116 @@ impl MacdIndicator {
    pub const fn value(&self) -> Option<MacdOutput> {
        self.last
    }
+
+    /// Vectorized flat batch for bindings: `n * 3` values laid out as
+    /// `[macd, signal, histogram]` per input row, warmup rows all `NaN`.
+    ///
+    /// For a fresh, all-finite slice long enough for a full output it runs the
+    /// fast EMA, slow EMA and signal EMA as three recurrences fused into a single
+    /// pass with one allocation — no `Option` per tick, no per-EMA intermediate
+    /// buffers, identical SMA-mean seeds (division) and `mul_add` recurrences. The
+    /// result is *bit-for-bit* equal to replaying `update`. Anything else (not
+    /// fresh, non-finite, or too short to emit) defers to the exact `update`
+    /// replay.
+    ///
+    /// Separate from the trait [`batch`](crate::BatchExt::batch), which stays a
+    /// bit-identical `update` replay; only the bindings call this.
+    pub fn batch_macd(&mut self, inputs: &[f64]) -> Vec<f64> {
+        let n = inputs.len();
+        let (fp, sp, gp) = (self.fast_period, self.slow_period, self.signal_period);
+        // First full output needs the slow EMA seeded (index sp-1) plus gp signal
+        // values: index sp + gp - 2. Below that, or non-fresh/non-finite, replay.
+        if self.last.is_some()
+            || !self.fast.is_fresh()
+            || !self.slow.is_fresh()
+            || !self.signal_ema.is_fresh()
+            || n < sp + gp - 1
+            || !inputs.iter().all(|x| x.is_finite())
+        {
+            let mut out = vec![f64::NAN; n * 3];
+            for (i, &x) in inputs.iter().enumerate() {
+                if let Some(o) = self.update(x) {
+                    out[i * 3] = o.macd;
+                    out[i * 3 + 1] = o.signal;
+                    out[i * 3 + 2] = o.histogram;
+                }
+            }
+            return out;
+        }
+
+        // Pre-sized output: warmup rows stay NaN, full-output rows are written in
+        // place by index — no per-row `push` length/capacity check.
+        let mut out = vec![f64::NAN; n * 3];
+        let (fa, fo) = (self.fast.alpha(), 1.0 - self.fast.alpha());
+        let (sa, so) = (self.slow.alpha(), 1.0 - self.slow.alpha());
+        let (ga, go) = (self.signal_ema.alpha(), 1.0 - self.signal_ema.alpha());
+        let (fp_f, sp_f, gp_f) = (fp as f64, sp as f64, gp as f64);
+
+        let (mut fast_val, mut slow_val, mut sig) = (0.0_f64, 0.0_f64, 0.0_f64);
+        let (mut fsum, mut ssum, mut gsum) = (0.0_f64, 0.0_f64, 0.0_f64);
+        let mut sig_count = 0usize; // signal-EMA seed progress (raw MACD values seen)
+        let mut sig_seeded = false;
+        let mut last = MacdOutput {
+            macd: 0.0,
+            signal: 0.0,
+            histogram: 0.0,
+        };
+
+        for (i, &x) in inputs.iter().enumerate() {
+            // Fast EMA: SMA-seeded at index fp-1, then recurrence.
+            if i < fp {
+                fsum += x;
+                if i == fp - 1 {
+                    fast_val = fsum / fp_f;
+                }
+            } else {
+                fast_val = fa.mul_add(x, fo * fast_val);
+            }
+            // Slow EMA: SMA-seeded at index sp-1, then recurrence.
+            if i < sp {
+                ssum += x;
+                if i == sp - 1 {
+                    slow_val = ssum / sp_f;
+                }
+            } else {
+                slow_val = sa.mul_add(x, so * slow_val);
+            }
+            if i + 1 < sp {
+                continue; // slow EMA not seeded yet → no raw MACD line
+            }
+            let macd = fast_val - slow_val;
+            // Signal EMA over the MACD line: SMA-seeded over its first gp values.
+            let signal = if sig_seeded {
+                sig = ga.mul_add(macd, go * sig);
+                sig
+            } else {
+                gsum += macd;
+                sig_count += 1;
+                if sig_count < gp {
+                    continue; // signal EMA still seeding → no full output
+                }
+                sig = gsum / gp_f;
+                sig_seeded = true;
+                sig
+            };
+            let histogram = macd - signal;
+            out[i * 3] = macd;
+            out[i * 3 + 1] = signal;
+            out[i * 3 + 2] = histogram;
+            last = MacdOutput {
+                macd,
+                signal,
+                histogram,
+            };
+        }
+
+        // Leave every sub-EMA and `last` where a full `update` replay would.
+        self.fast.seed_to(fast_val);
+        self.slow.seed_to(slow_val);
+        self.signal_ema.seed_to(sig);
+        self.last = Some(last);
+        out
+    }
 }

 impl Indicator for MacdIndicator {
@@ -256,6 +366,79 @@ mod tests {
        assert_eq!(macd.update(1.0), None);
    }

+    fn bits_eq(a: &[f64], b: &[f64]) -> bool {
+        a.len() == b.len()
+            && a.iter()
+                .zip(b)
+                .all(|(x, y)| x == y || (x.is_nan() && y.is_nan()))
+    }
+
+    /// Flat `n*3` `[macd, signal, histogram]` replay of `update`.
+    fn macd_replay(series: &[f64]) -> Vec<f64> {
+        let mut m = MacdIndicator::classic();
+        let mut out = Vec::with_capacity(series.len() * 3);
+        for &x in series {
+            match m.update(x) {
+                Some(o) => out.extend_from_slice(&[o.macd, o.signal, o.histogram]),
+                None => out.extend_from_slice(&[f64::NAN; 3]),
+            }
+        }
+        out
+    }
+
+    #[test]
+    fn batch_macd_fast_path_is_bit_identical() {
+        let series: Vec<f64> = (0..300)
+            .map(|i| (f64::from(i) * 0.4).cos() * 10.0 + 100.0)
+            .collect();
+        let mut macd = MacdIndicator::classic();
+        let got = macd.batch_macd(&series);
+        assert!(bits_eq(&got, &macd_replay(&series)));
+        // Sub-EMA + last state left where the replay would: continued update agrees.
+        let mut ref_macd = MacdIndicator::classic();
+        for &x in &series {
+            ref_macd.update(x);
+        }
+        let (a, b) = (macd.update(101.0), ref_macd.update(101.0));
+        assert_eq!(a.is_some(), b.is_some());
+        assert_relative_eq!(a.unwrap().macd, b.unwrap().macd, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn batch_macd_falls_back_on_non_finite() {
+        let mut series: Vec<f64> = (0..60).map(|i| f64::from(i) + 100.0).collect();
+        series[40] = f64::NAN;
+        let mut macd = MacdIndicator::classic();
+        assert!(bits_eq(&macd.batch_macd(&series), &macd_replay(&series)));
+    }
+
+    #[test]
+    fn batch_macd_falls_back_when_not_fresh() {
+        let series: Vec<f64> = (0..60).map(|i| f64::from(i) + 100.0).collect();
+        let mut macd = MacdIndicator::classic();
+        macd.update(50.0);
+        let mut ref_macd = MacdIndicator::classic();
+        ref_macd.update(50.0);
+        let mut want = Vec::new();
+        for &x in &series {
+            match ref_macd.update(x) {
+                Some(o) => want.extend_from_slice(&[o.macd, o.signal, o.histogram]),
+                None => want.extend_from_slice(&[f64::NAN; 3]),
+            }
+        }
+        assert!(bits_eq(&macd.batch_macd(&series), &want));
+    }
+
+    #[test]
+    fn batch_macd_too_short_for_output_falls_back() {
+        // n < slow + signal - 1 (= 34): no full output, routed to the replay.
+        let series: Vec<f64> = (0..20).map(|i| f64::from(i) + 100.0).collect();
+        let mut macd = MacdIndicator::classic();
+        let got = macd.batch_macd(&series);
+        assert!(bits_eq(&got, &macd_replay(&series)));
+        assert!(got.iter().all(|x| x.is_nan()));
+    }
+
    #[test]
    fn ignores_non_finite_input() {
        let mut macd = MacdIndicator::classic();
@@ -0,0 +1,184 @@
+//! MACD Histogram (standalone).
+
+use crate::error::Result;
+use crate::indicators::macd::MacdIndicator;
+use crate::traits::Indicator;
+
+/// MACD Histogram — the `macd − signal` bar of [`MacdIndicator`] as a
+/// standalone scalar indicator.
+///
+/// ```text
+/// macd      = EMA(fast) − EMA(slow)
+/// signal    = EMA(macd, signal)
+/// histogram = macd − signal
+/// ```
+///
+/// The histogram is the most actively traded part of MACD: it crosses zero
+/// exactly when the MACD line crosses its signal, and its slope measures
+/// whether that momentum is accelerating or fading. This wrapper exposes just
+/// that series for pipelines that want a plain `f64` stream rather than the
+/// full [`MacdOutput`](crate::MacdOutput); for the line and signal alongside
+/// it, use [`MacdIndicator`](crate::MacdIndicator) directly.
+///
+/// Standard parameters are `fast = 12`, `slow = 26`, `signal = 9`, so the
+/// first value lands after `slow + signal − 1` inputs — exactly when
+/// [`MacdIndicator`] emits its first full output.
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Indicator, MacdHistogram};
+///
+/// let mut indicator = MacdHistogram::new(12, 26, 9).unwrap();
+/// let mut last = None;
+/// for i in 0..80 {
+///     last = indicator.update(100.0 + f64::from(i));
+/// }
+/// assert!(last.is_some());
+/// ```
+#[derive(Debug, Clone)]
+pub struct MacdHistogram {
+    macd: MacdIndicator,
+}
+
+impl MacdHistogram {
+    /// Construct a MACD histogram with the given periods.
+    ///
+    /// # Errors
+    ///
+    /// Returns [`Error::PeriodZero`] if any period is zero, and
+    /// [`Error::InvalidPeriod`] if `fast >= slow`.
+    pub fn new(fast: usize, slow: usize, signal: usize) -> Result<Self> {
+        Ok(Self {
+            macd: MacdIndicator::new(fast, slow, signal)?,
+        })
+    }
+
+    /// Default `(12, 26, 9)` configuration, matching every classical chart package.
+    pub fn classic() -> Self {
+        Self::new(12, 26, 9).expect("classic MACD periods are valid")
+    }
+
+    /// Configured periods as `(fast, slow, signal)`.
+    pub const fn periods(&self) -> (usize, usize, usize) {
+        self.macd.periods()
+    }
+}
+
+impl Indicator for MacdHistogram {
+    type Input = f64;
+    type Output = f64;
+
+    fn update(&mut self, input: f64) -> Option<f64> {
+        self.macd.update(input).map(|out| out.histogram)
+    }
+
+    fn reset(&mut self) {
+        self.macd.reset();
+    }
+
+    fn warmup_period(&self) -> usize {
+        self.macd.warmup_period()
+    }
+
+    fn is_ready(&self) -> bool {
+        self.macd.is_ready()
+    }
+
+    fn name(&self) -> &'static str {
+        "MacdHistogram"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::error::Error;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    #[test]
+    fn rejects_invalid_periods() {
+        assert!(matches!(
+            MacdHistogram::new(0, 26, 9),
+            Err(Error::PeriodZero)
+        ));
+        assert!(matches!(
+            MacdHistogram::new(12, 26, 0),
+            Err(Error::PeriodZero)
+        ));
+        assert!(matches!(
+            MacdHistogram::new(26, 12, 9),
+            Err(Error::InvalidPeriod { .. })
+        ));
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let osc = MacdHistogram::classic();
+        assert_eq!(osc.periods(), (12, 26, 9));
+        assert_eq!(osc.name(), "MacdHistogram");
+        assert_eq!(osc.warmup_period(), 26 + 9 - 1);
+        assert!(!osc.is_ready());
+    }
+
+    #[test]
+    fn equals_macd_histogram_field() {
+        // The standalone series must be exactly MacdIndicator's histogram bar.
+        let prices: Vec<f64> = (1..=120)
+            .map(|i| 100.0 + (f64::from(i) * 0.25).sin() * 8.0)
+            .collect();
+        let hist = MacdHistogram::classic().batch(&prices);
+        let full = MacdIndicator::classic().batch(&prices);
+        assert_eq!(hist.len(), full.len());
+        for (h, m) in hist.iter().zip(full.iter()) {
+            assert_eq!(h.is_some(), m.is_some());
+            if let (Some(h), Some(m)) = (h, m) {
+                assert_relative_eq!(*h, m.histogram, epsilon = 1e-12);
+            }
+        }
+    }
+
+    #[test]
+    fn warmup_emits_first_value_at_warmup_period() {
+        let mut osc = MacdHistogram::new(3, 6, 3).unwrap();
+        let warmup = osc.warmup_period();
+        assert_eq!(warmup, 6 + 3 - 1);
+        for i in 1..warmup {
+            assert!(osc.update(100.0 + i as f64).is_none());
+        }
+        assert!(osc.update(100.0 + warmup as f64).is_some());
+        assert!(osc.is_ready());
+    }
+
+    #[test]
+    fn constant_series_converges_to_zero() {
+        let mut osc = MacdHistogram::classic();
+        let out = osc.batch(&[100.0_f64; 200]);
+        let last = out.iter().rev().flatten().next().expect("emits a value");
+        assert_relative_eq!(*last, 0.0, epsilon = 1e-9);
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let prices: Vec<f64> = (1..=100)
+            .map(|i| (f64::from(i) * 0.4).cos() * 10.0)
+            .collect();
+        let mut a = MacdHistogram::classic();
+        let mut b = MacdHistogram::classic();
+        assert_eq!(
+            a.batch(&prices),
+            prices.iter().map(|p| b.update(*p)).collect::<Vec<_>>()
+        );
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut osc = MacdHistogram::classic();
+        osc.batch(&(1..=80).map(f64::from).collect::<Vec<_>>());
+        assert!(osc.is_ready());
+        osc.reset();
+        assert!(!osc.is_ready());
+        assert_eq!(osc.update(1.0), None);
+    }
+}
@@ -0,0 +1,237 @@
+//! Median Channel — a robust median ± MAD envelope.
+
+use std::collections::VecDeque;
+
+use crate::error::{Error, Result};
+use crate::indicators::rolling_quantile::quantile_sorted;
+use crate::traits::Indicator;
+
+/// Median Channel output.
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub struct MedianChannelOutput {
+    /// Upper band: `median + multiplier · MAD`.
+    pub upper: f64,
+    /// Middle line: the rolling median.
+    pub middle: f64,
+    /// Lower band: `median − multiplier · MAD`.
+    pub lower: f64,
+}
+
+/// Median Channel: a robust analogue of Bollinger Bands built from the rolling
+/// median and the median absolute deviation (MAD).
+///
+/// ```text
+/// middle = median(close, period)
+/// MAD    = median( | close_i − middle | )
+/// upper  = middle + multiplier · MAD
+/// lower  = middle − multiplier · MAD
+/// ```
+///
+/// Where [`BollingerBands`](crate::BollingerBands) centre on the mean and scale
+/// by the standard deviation — both of which a single spike can drag
+/// arbitrarily far — the Median Channel uses two order statistics. The
+/// breakdown point of the median and MAD is 50%: up to half the window can be
+/// contaminated before the centre or width is materially distorted. That makes
+/// the channel well suited to noisy, gap-prone, or fat-tailed series where
+/// Bollinger Bands flare on every outlier. Both quantiles use the type-7
+/// interpolation shared with [`RollingQuantile`](crate::RollingQuantile).
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Indicator, MedianChannel};
+///
+/// let mut indicator = MedianChannel::new(20, 2.0).unwrap();
+/// let mut last = None;
+/// for i in 0..40 {
+///     last = indicator.update(100.0 + f64::from(i % 5));
+/// }
+/// assert!(last.is_some());
+/// ```
+#[derive(Debug, Clone)]
+pub struct MedianChannel {
+    period: usize,
+    multiplier: f64,
+    window: VecDeque<f64>,
+    scratch: Vec<f64>,
+    deviations: Vec<f64>,
+}
+
+impl MedianChannel {
+    /// Construct a new Median Channel.
+    ///
+    /// # Errors
+    /// Returns [`Error::PeriodZero`] if `period == 0`, or
+    /// [`Error::NonPositiveMultiplier`] if `multiplier` is not strictly
+    /// positive and finite.
+    pub fn new(period: usize, multiplier: f64) -> Result<Self> {
+        if period == 0 {
+            return Err(Error::PeriodZero);
+        }
+        if !multiplier.is_finite() || multiplier <= 0.0 {
+            return Err(Error::NonPositiveMultiplier);
+        }
+        Ok(Self {
+            period,
+            multiplier,
+            window: VecDeque::with_capacity(period),
+            scratch: Vec::with_capacity(period),
+            deviations: Vec::with_capacity(period),
+        })
+    }
+
+    /// Configured period.
+    pub const fn period(&self) -> usize {
+        self.period
+    }
+
+    /// Configured multiplier.
+    pub const fn multiplier(&self) -> f64 {
+        self.multiplier
+    }
+}
+
+impl Indicator for MedianChannel {
+    type Input = f64;
+    type Output = MedianChannelOutput;
+
+    fn update(&mut self, value: f64) -> Option<MedianChannelOutput> {
+        if self.window.len() == self.period {
+            self.window.pop_front();
+        }
+        self.window.push_back(value);
+        if self.window.len() < self.period {
+            return None;
+        }
+        self.scratch.clear();
+        self.scratch.extend(self.window.iter().copied());
+        self.scratch.sort_by(f64::total_cmp);
+        let median = quantile_sorted(&self.scratch, 0.5);
+
+        self.deviations.clear();
+        for &v in &self.window {
+            self.deviations.push((v - median).abs());
+        }
+        self.deviations.sort_by(f64::total_cmp);
+        let mad = quantile_sorted(&self.deviations, 0.5);
+        let offset = self.multiplier * mad;
+
+        Some(MedianChannelOutput {
+            upper: median + offset,
+            middle: median,
+            lower: median - offset,
+        })
+    }
+
+    fn reset(&mut self) {
+        self.window.clear();
+        self.scratch.clear();
+        self.deviations.clear();
+    }
+
+    fn warmup_period(&self) -> usize {
+        self.period
+    }
+
+    fn is_ready(&self) -> bool {
+        self.window.len() == self.period
+    }
+
+    fn name(&self) -> &'static str {
+        "MedianChannel"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    #[test]
+    fn rejects_zero_period() {
+        assert!(matches!(MedianChannel::new(0, 2.0), Err(Error::PeriodZero)));
+        assert!(MedianChannel::new(1, 2.0).is_ok());
+    }
+
+    #[test]
+    fn rejects_non_positive_multiplier() {
+        assert!(matches!(
+            MedianChannel::new(20, 0.0),
+            Err(Error::NonPositiveMultiplier)
+        ));
+        assert!(matches!(
+            MedianChannel::new(20, -1.0),
+            Err(Error::NonPositiveMultiplier)
+        ));
+        assert!(matches!(
+            MedianChannel::new(20, f64::NAN),
+            Err(Error::NonPositiveMultiplier)
+        ));
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let mc = MedianChannel::new(20, 2.0).unwrap();
+        assert_eq!(mc.period(), 20);
+        assert_relative_eq!(mc.multiplier(), 2.0, epsilon = 1e-12);
+        assert_eq!(mc.warmup_period(), 20);
+        assert_eq!(mc.name(), "MedianChannel");
+        assert!(!mc.is_ready());
+    }
+
+    #[test]
+    fn warms_up_then_emits() {
+        let mut mc = MedianChannel::new(5, 2.0).unwrap();
+        for v in [1.0, 2.0, 3.0, 4.0] {
+            assert!(mc.update(v).is_none());
+        }
+        assert!(mc.update(5.0).is_some());
+        assert!(mc.is_ready());
+    }
+
+    #[test]
+    fn known_channel() {
+        // [1,2,3,4,5]: median 3; |dev| sorted [0,1,1,2,2] -> MAD 1.
+        // upper = 3 + 2*1 = 5; lower = 3 - 2*1 = 1.
+        let mut mc = MedianChannel::new(5, 2.0).unwrap();
+        let out = mc.batch(&[1.0, 2.0, 3.0, 4.0, 5.0]);
+        let last = out[4].unwrap();
+        assert_relative_eq!(last.middle, 3.0, epsilon = 1e-12);
+        assert_relative_eq!(last.upper, 5.0, epsilon = 1e-12);
+        assert_relative_eq!(last.lower, 1.0, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn robust_to_outlier() {
+        // Replacing the last value with a huge spike leaves the median centre
+        // unchanged (still the middle order statistic).
+        let mut mc = MedianChannel::new(5, 2.0).unwrap();
+        let out = mc.batch(&[1.0, 2.0, 3.0, 4.0, 1_000.0]);
+        assert_relative_eq!(out[4].unwrap().middle, 3.0, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn rolling_window_evicts_oldest() {
+        // Ten values through a period-5 window: only the last five survive,
+        // reproducing the `known_channel` window.
+        let mut mc = MedianChannel::new(5, 2.0).unwrap();
+        let out = mc.batch(&[10.0, 10.0, 10.0, 10.0, 10.0, 1.0, 2.0, 3.0, 4.0, 5.0]);
+        let last = out[9].unwrap();
+        assert_relative_eq!(last.middle, 3.0, epsilon = 1e-12);
+        assert_relative_eq!(last.upper, 5.0, epsilon = 1e-12);
+        assert_relative_eq!(last.lower, 1.0, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut mc = MedianChannel::new(5, 2.0).unwrap();
+        for v in [1.0, 2.0, 3.0, 4.0, 5.0] {
+            mc.update(v);
+        }
+        assert!(mc.is_ready());
+        mc.reset();
+        assert!(!mc.is_ready());
+        assert!(mc.update(1.0).is_none());
+    }
+}
@@ -0,0 +1,205 @@
+//! Median Moving Average.
+
+use std::collections::VecDeque;
+
+use crate::error::{Error, Result};
+use crate::traits::Indicator;
+
+/// Median Moving Average — the rolling median of the last `period` inputs.
+///
+/// For an odd `period` the output is the middle order statistic of the window;
+/// for an even `period` it is the average of the two central values. Because it
+/// is a rank statistic rather than a sum, the median MA is far more robust to
+/// single outliers than the [`Sma`](crate::Sma): a lone spike shifts the rank
+/// by at most one position instead of dragging the whole average.
+///
+/// Each `update` slides the window and computes the median by sorting a copy of
+/// the `period` buffered values — O(`period` · log `period`) per step, with the
+/// period fixed and bounded.
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Indicator, MedianMa};
+///
+/// let mut indicator = MedianMa::new(5).unwrap();
+/// let mut last = None;
+/// for i in 0..80 {
+///     last = indicator.update(100.0 + f64::from(i));
+/// }
+/// assert!(last.is_some());
+/// ```
+#[derive(Debug, Clone)]
+pub struct MedianMa {
+    period: usize,
+    window: VecDeque<f64>,
+}
+
+impl MedianMa {
+    /// Construct a new median moving average over `period` inputs.
+    ///
+    /// # Errors
+    ///
+    /// Returns [`Error::PeriodZero`] if `period == 0`.
+    pub fn new(period: usize) -> Result<Self> {
+        if period == 0 {
+            return Err(Error::PeriodZero);
+        }
+        Ok(Self {
+            period,
+            window: VecDeque::with_capacity(period),
+        })
+    }
+
+    /// Configured period.
+    pub const fn period(&self) -> usize {
+        self.period
+    }
+
+    /// Current value if the window is full.
+    pub fn value(&self) -> Option<f64> {
+        if self.window.len() != self.period {
+            return None;
+        }
+        let mut sorted: Vec<f64> = self.window.iter().copied().collect();
+        sorted.sort_by(|a, b| a.partial_cmp(b).expect("window holds only finite values"));
+        let mid = self.period / 2;
+        if self.period % 2 == 1 {
+            Some(sorted[mid])
+        } else {
+            Some(f64::midpoint(sorted[mid - 1], sorted[mid]))
+        }
+    }
+}
+
+impl Indicator for MedianMa {
+    type Input = f64;
+    type Output = f64;
+
+    fn update(&mut self, input: f64) -> Option<f64> {
+        if !input.is_finite() {
+            return self.value();
+        }
+        if self.window.len() == self.period {
+            self.window.pop_front();
+        }
+        self.window.push_back(input);
+        self.value()
+    }
+
+    fn reset(&mut self) {
+        self.window.clear();
+    }
+
+    fn warmup_period(&self) -> usize {
+        self.period
+    }
+
+    fn is_ready(&self) -> bool {
+        self.window.len() == self.period
+    }
+
+    fn name(&self) -> &'static str {
+        "MedianMA"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    #[test]
+    fn new_rejects_zero_period() {
+        assert!(matches!(MedianMa::new(0), Err(Error::PeriodZero)));
+    }
+
+    /// Cover the const accessor `period` and the Indicator-impl `warmup_period`
+    /// + `name`.
+    #[test]
+    fn accessors_and_metadata() {
+        let mma = MedianMa::new(7).unwrap();
+        assert_eq!(mma.period(), 7);
+        assert_eq!(mma.warmup_period(), 7);
+        assert_eq!(mma.name(), "MedianMA");
+    }
+
+    #[test]
+    fn warmup_returns_none_then_odd_median() {
+        let mut mma = MedianMa::new(3).unwrap();
+        assert_eq!(mma.update(5.0), None);
+        assert_eq!(mma.update(1.0), None);
+        // median of [5, 1, 3] = 3 (middle order statistic).
+        assert_relative_eq!(mma.update(3.0).unwrap(), 3.0, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn even_period_averages_two_central_values() {
+        // median of [1, 2, 3, 4] = (2 + 3) / 2 = 2.5.
+        let mut mma = MedianMa::new(4).unwrap();
+        let v = mma.batch(&[1.0, 2.0, 3.0, 4.0]);
+        assert_relative_eq!(v[3].unwrap(), 2.5, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn robust_to_single_outlier() {
+        // A lone spike does not move the median of an odd window the way it
+        // would move an SMA. median of [10, 11, 9999] = 11.
+        let mut mma = MedianMa::new(3).unwrap();
+        let v = mma.batch(&[10.0, 11.0, 9999.0]);
+        assert_relative_eq!(v[2].unwrap(), 11.0, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn period_one_is_pass_through() {
+        let mut mma = MedianMa::new(1).unwrap();
+        assert_relative_eq!(mma.update(5.5).unwrap(), 5.5, epsilon = 1e-12);
+        assert_relative_eq!(mma.update(7.5).unwrap(), 7.5, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn slides_window_correctly() {
+        // After [1,2,3] the window slides to [2,3,4] -> median 3, then [3,4,5] -> 4.
+        let mut mma = MedianMa::new(3).unwrap();
+        let v = mma.batch(&[1.0, 2.0, 3.0, 4.0, 5.0]);
+        assert_relative_eq!(v[2].unwrap(), 2.0, epsilon = 1e-12);
+        assert_relative_eq!(v[3].unwrap(), 3.0, epsilon = 1e-12);
+        assert_relative_eq!(v[4].unwrap(), 4.0, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut mma = MedianMa::new(4).unwrap();
+        mma.batch(&[1.0, 2.0, 3.0, 4.0, 5.0]);
+        assert!(mma.is_ready());
+        mma.reset();
+        assert!(!mma.is_ready());
+        assert_eq!(mma.update(10.0), None);
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let prices: Vec<f64> = (1..=20).map(|i| (f64::from(i) * 0.7).sin() * 5.0).collect();
+        let mut a = MedianMa::new(5).unwrap();
+        let mut b = MedianMa::new(5).unwrap();
+        assert_eq!(
+            a.batch(&prices),
+            prices.iter().map(|p| b.update(*p)).collect::<Vec<_>>()
+        );
+    }
+
+    #[test]
+    fn ignores_non_finite_input_but_keeps_state() {
+        let mut mma = MedianMa::new(3).unwrap();
+        mma.update(5.0);
+        mma.update(1.0);
+        let ready = mma
+            .update(3.0)
+            .expect("MedianMA(3) ready after three inputs");
+        assert_eq!(mma.update(f64::NAN), Some(ready));
+        assert_eq!(mma.update(f64::INFINITY), Some(ready));
+        // Window still [5, 1, 3] -> next real input slides to [1, 3, 8] -> median 3.
+        assert_relative_eq!(mma.update(8.0).unwrap(), 3.0, epsilon = 1e-12);
+    }
+}
@@ -16,7 +16,10 @@ mod acceleration_bands;
 mod accelerator_oscillator;
 mod ad_oscillator;
 mod ad_volume_line;
+mod adaptive_cci;
 mod adaptive_cycle;
+mod adaptive_laguerre_filter;
+mod adaptive_rsi;
 mod adl;
 mod advance_block;
 mod advance_decline;
@@ -26,28 +29,37 @@ mod adxr;
 mod alligator;
 mod alma;
 mod alpha;
+mod amihud_illiquidity;
 mod anchored_rsi;
 mod anchored_vwap;
+mod andrews_pitchfork;
 mod apo;
 mod aroon;
 mod aroon_oscillator;
 mod atr;
 mod atr_bands;
+mod atr_ratchet;
 mod atr_trailing_stop;
 mod auto_fib;
 mod autocorrelation;
+mod autocorrelation_periodogram;
 mod average_daily_range;
 mod average_drawdown;
 mod avg_price;
 mod awesome_oscillator;
 mod awesome_oscillator_histogram;
 mod balance_of_power;
+mod bandpass_filter;
 mod bat;
 mod belt_hold;
 mod beta;
 mod beta_neutral_spread;
+mod better_volume;
+mod bipower_variation;
+mod body_size_pct;
 mod bollinger;
 mod bollinger_bandwidth;
+mod bomar_bands;
 mod breadth_thrust;
 mod breakaway;
 mod bullish_percent_index;
@@ -57,6 +69,7 @@ mod calmar_ratio;
 mod camarilla_pivots;
 mod cci;
 mod center_of_gravity;
+mod central_pivot_range;
 mod cfo;
 mod chaikin_oscillator;
 mod chaikin_volatility;
@@ -64,6 +77,7 @@ mod chande_kroll_stop;
 mod chandelier_exit;
 mod choppiness_index;
 mod classic_pivots;
+mod close_vs_open;
 mod closing_marubozu;
 mod cmf;
 mod cmo;
@@ -73,6 +87,7 @@ mod concealing_baby_swallow;
 mod conditional_value_at_risk;
 mod connors_rsi;
 mod coppock;
+mod correlation_trend_indicator;
 mod counterattack;
 mod crab;
 mod cumulative_volume_index;
@@ -87,7 +102,9 @@ mod dema;
 mod demand_index;
 mod demark_pivots;
 mod depth_slope;
+mod derivative_oscillator;
 mod detrended_std_dev;
+mod disparity_index;
 mod distance_ssd;
 mod doji;
 mod doji_star;
@@ -100,15 +117,22 @@ mod dpo;
 mod dragonfly_doji;
 mod drawdown_duration;
 mod dx;
+mod dynamic_momentum_index;
 mod ease_of_movement;
 mod effective_spread;
 mod ehlers_stochastic;
+mod ehma;
 mod elder_impulse;
+mod elder_ray;
+mod elder_safezone;
 mod ema;
 mod empirical_mode_decomposition;
 mod engulfing;
+mod even_better_sinewave;
 mod evening_doji_star;
 mod evwma;
+mod ewma_volatility;
+mod expectancy;
 mod falling_three_methods;
 mod fama;
 mod fib_arcs;
@@ -120,6 +144,7 @@ mod fib_projection;
 mod fib_retracement;
 mod fib_time_zones;
 mod fibonacci_pivots;
+mod fisher_rsi;
 mod fisher_transform;
 mod flag_pennant;
 mod footprint;
@@ -132,8 +157,12 @@ mod funding_rate_mean;
 mod funding_rate_zscore;
 mod gain_loss_ratio;
 mod gap_side_by_side_white;
+mod garch11;
 mod garman_klass;
 mod gartley;
+mod gator_oscillator;
+mod generalized_dema;
+mod geometric_ma;
 mod golden_pocket;
 mod granger_causality;
 mod gravestone_doji;
@@ -143,13 +172,16 @@ mod harami;
 mod head_and_shoulders;
 mod heikin_ashi;
 mod high_low_index;
+mod high_low_range;
 mod high_wave;
+mod highpass_filter;
 mod hikkake;
 mod hikkake_modified;
 mod hilbert_dominant_cycle;
 mod hilo_activator;
 mod historical_volatility;
 mod hma;
+mod holt_winters;
 mod homing_pigeon;
 mod ht_dcphase;
 mod ht_phasor;
@@ -163,15 +195,22 @@ mod inertia;
 mod information_ratio;
 mod initial_balance;
 mod instantaneous_trendline;
+mod intraday_intensity;
+mod intraday_momentum_index;
 mod intraday_volatility_profile;
 mod inverse_fisher_transform;
 mod inverted_hammer;
+mod jarque_bera;
 mod jma;
+mod jump_indicator;
 mod kagi_bars;
 mod kalman_hedge_ratio;
 mod kama;
+mod kase_devstop;
+mod kase_permission_stochastic;
 mod kelly_criterion;
 mod keltner;
+mod kendall_tau;
 mod kicking;
 mod kicking_by_length;
 mod kst;
@@ -187,6 +226,7 @@ mod linreg_channel;
 mod linreg_intercept;
 mod linreg_slope;
 mod liquidation_features;
+mod log_return;
 mod long_legged_doji;
 mod long_line;
 mod long_short_ratio;
@@ -194,6 +234,7 @@ mod ma_envelope;
 mod macd;
 mod macd_ext;
 mod macd_fix;
+mod macd_histogram;
 mod mama;
 mod market_facilitation_index;
 mod marubozu;
@@ -205,6 +246,8 @@ mod mcclellan_oscillator;
 mod mcclellan_summation_index;
 mod mcginley_dynamic;
 mod median_absolute_deviation;
+mod median_channel;
+mod median_ma;
 mod median_price;
 mod mfi;
 mod microprice;
@@ -212,11 +255,14 @@ mod mid_point;
 mod mid_price;
 mod minus_di;
 mod minus_dm;
+mod modified_ma_stop;
 mod mom;
 mod morning_doji_star;
 mod morning_evening_star;
+mod murrey_math_lines;
 mod natr;
 mod new_highs_new_lows;
+mod nrtr;
 mod nvi;
 mod ob_imbalance_full;
 mod ob_imbalance_top1;
@@ -229,6 +275,7 @@ mod omega_ratio;
 mod on_neck;
 mod opening_marubozu;
 mod opening_range;
+mod order_flow_imbalance;
 mod ou_half_life;
 mod overnight_gap;
 mod overnight_intraday_return;
@@ -242,48 +289,69 @@ mod percent_b;
 mod percentage_trailing_stop;
 mod pgo;
 mod piercing_dark_cloud;
+mod pivot_reversal;
 mod plus_di;
 mod plus_dm;
 mod pmo;
 mod point_and_figure_bars;
+mod polarized_fractal_efficiency;
 mod ppo;
+mod ppo_histogram;
 mod profit_factor;
+mod projection_bands;
+mod projection_oscillator;
 mod psar;
 mod pvi;
+mod qqe;
+mod qstick;
+mod quartile_bands;
 mod quoted_spread;
 mod r_squared;
 mod realized_spread;
+mod realized_volatility;
 mod recovery_factor;
 mod rectangle_range;
+mod reflex;
+mod regime_label;
 mod relative_strength_ab;
 mod renko_bars;
 mod renko_trailing_stop;
 mod rickshaw_man;
 mod rising_three_methods;
+mod rmi;
 mod roc;
 mod rocp;
 mod rocr;
 mod rocr100;
 mod rogers_satchell;
+mod roll_measure;
 mod rolling_correlation;
 mod rolling_covariance;
+mod rolling_iqr;
+mod rolling_min_max_scaler;
+mod rolling_percentile_rank;
+mod rolling_quantile;
 mod roofing_filter;
 mod rsi;
+mod rsx;
 mod rvi;
 mod rvi_volatility;
 mod rwi;
+mod sample_entropy;
 mod sar_ext;
 mod seasonal_z_score;
 mod separating_lines;
 mod session_high_low;
 mod session_range;
 mod session_vwap;
+mod shannon_entropy;
 mod shark;
 mod sharpe_ratio;
 mod shooting_star;
 mod short_line;
 mod signed_volume;
 mod sine_wave;
+mod sine_weighted_ma;
 mod skewness;
 mod sma;
 mod smi;
@@ -291,6 +359,7 @@ mod smma;
 mod sortino_ratio;
 mod spearman_correlation;
 mod spinning_top;
+mod spread_ar1_coefficient;
 mod spread_bollinger_bands;
 mod spread_hurst;
 mod stalled_pattern;
@@ -303,6 +372,7 @@ mod step_trailing_stop;
 mod stick_sandwich;
 mod stoch_rsi;
 mod stochastic;
+mod stochastic_cci;
 mod super_smoother;
 mod super_trend;
 mod t3;
@@ -332,9 +402,14 @@ mod three_stars_in_south;
 mod thrusting;
 mod tick_index;
 mod tii;
+mod time_based_stop;
 mod time_of_day_return_profile;
 mod tpo_profile;
 mod trade_imbalance;
+mod trade_volume_index;
+mod trend_label;
+mod trend_strength_index;
+mod trendflex;
 mod treynor_ratio;
 mod triangle;
 mod trima;
@@ -343,16 +418,20 @@ mod triple_top_bottom;
 mod trix;
 mod true_range;
 mod tsf;
+mod tsf_oscillator;
 mod tsi;
 mod tsv;
 mod ttm_squeeze;
+mod ttm_trend;
 mod turn_of_month;
 mod tweezer;
+mod twiggs_money_flow;
 mod two_crows;
 mod typical_price;
 mod ulcer_index;
 mod ultimate_oscillator;
 mod unique_three_river;
+mod universal_oscillator;
 mod up_down_volume_ratio;
 mod upside_gap_three_methods;
 mod upside_gap_two_crows;
@@ -362,21 +441,32 @@ mod variance;
 mod variance_ratio;
 mod vertical_horizontal_filter;
 mod vidya;
+mod volatility_cone;
+mod volatility_of_volatility;
+mod volatility_ratio;
 mod volty_stop;
 mod volume_by_time_profile;
 mod volume_oscillator;
 mod volume_profile;
+mod volume_rsi;
+mod volume_weighted_macd;
+mod volume_weighted_sr;
 mod vortex;
+mod vpin;
 mod vpt;
 mod vwap;
 mod vwap_stddev_bands;
 mod vwma;
 mod vzo;
+mod wad;
+mod wave_pm;
 mod wave_trend;
 mod wedge;
 mod weighted_close;
+mod wick_ratio;
 mod williams_fractals;
 mod williams_r;
+mod win_rate;
 mod wma;
 mod woodie_pivots;
 mod yang_zhang;
@@ -393,7 +483,10 @@ pub use acceleration_bands::{AccelerationBands, AccelerationBandsOutput};
 pub use accelerator_oscillator::AcceleratorOscillator;
 pub use ad_oscillator::AdOscillator;
 pub use ad_volume_line::AdVolumeLine;
+pub use adaptive_cci::AdaptiveCci;
 pub use adaptive_cycle::AdaptiveCycle;
+pub use adaptive_laguerre_filter::AdaptiveLaguerreFilter;
+pub use adaptive_rsi::AdaptiveRsi;
 pub use adl::Adl;
 pub use advance_block::AdvanceBlock;
 pub use advance_decline::AdvanceDecline;
@@ -403,28 +496,37 @@ pub use adxr::Adxr;
 pub use alligator::{Alligator, AlligatorOutput};
 pub use alma::Alma;
 pub use alpha::Alpha;
+pub use amihud_illiquidity::AmihudIlliquidity;
 pub use anchored_rsi::AnchoredRsi;
 pub use anchored_vwap::AnchoredVwap;
+pub use andrews_pitchfork::{AndrewsPitchfork, AndrewsPitchforkOutput};
 pub use apo::Apo;
 pub use aroon::{Aroon, AroonOutput};
 pub use aroon_oscillator::AroonOscillator;
 pub use atr::Atr;
 pub use atr_bands::{AtrBands, AtrBandsOutput};
+pub use atr_ratchet::{AtrRatchet, AtrRatchetOutput};
 pub use atr_trailing_stop::AtrTrailingStop;
 pub use auto_fib::{AutoFib, AutoFibOutput};
 pub use autocorrelation::Autocorrelation;
+pub use autocorrelation_periodogram::AutocorrelationPeriodogram;
 pub use average_daily_range::AverageDailyRange;
 pub use average_drawdown::AverageDrawdown;
 pub use avg_price::AvgPrice;
 pub use awesome_oscillator::AwesomeOscillator;
 pub use awesome_oscillator_histogram::AwesomeOscillatorHistogram;
 pub use balance_of_power::BalanceOfPower;
+pub use bandpass_filter::BandpassFilter;
 pub use bat::Bat;
 pub use belt_hold::BeltHold;
 pub use beta::Beta;
 pub use beta_neutral_spread::BetaNeutralSpread;
+pub use better_volume::BetterVolume;
+pub use bipower_variation::BipowerVariation;
+pub use body_size_pct::BodySizePct;
 pub use bollinger::{BollingerBands, BollingerOutput};
 pub use bollinger_bandwidth::BollingerBandwidth;
+pub use bomar_bands::{BomarBands, BomarBandsOutput};
 pub use breadth_thrust::BreadthThrust;
 pub use breakaway::Breakaway;
 pub use bullish_percent_index::BullishPercentIndex;
@@ -434,6 +536,7 @@ pub use calmar_ratio::CalmarRatio;
 pub use camarilla_pivots::{Camarilla, CamarillaPivotsOutput};
 pub use cci::Cci;
 pub use center_of_gravity::CenterOfGravity;
+pub use central_pivot_range::{CentralPivotRange, CentralPivotRangeOutput};
 pub use cfo::Cfo;
 pub use chaikin_oscillator::ChaikinOscillator;
 pub use chaikin_volatility::ChaikinVolatility;
@@ -441,6 +544,7 @@ pub use chande_kroll_stop::{ChandeKrollStop, ChandeKrollStopOutput};
 pub use chandelier_exit::{ChandelierExit, ChandelierExitOutput};
 pub use choppiness_index::ChoppinessIndex;
 pub use classic_pivots::{ClassicPivots, ClassicPivotsOutput};
+pub use close_vs_open::CloseVsOpen;
 pub use closing_marubozu::ClosingMarubozu;
 pub use cmf::ChaikinMoneyFlow;
 pub use cmo::Cmo;
@@ -450,6 +554,7 @@ pub use concealing_baby_swallow::ConcealingBabySwallow;
 pub use conditional_value_at_risk::ConditionalValueAtRisk;
 pub use connors_rsi::ConnorsRsi;
 pub use coppock::Coppock;
+pub use correlation_trend_indicator::CorrelationTrendIndicator;
 pub use counterattack::Counterattack;
 pub use crab::Crab;
 pub use cumulative_volume_index::CumulativeVolumeIndex;
@@ -464,7 +569,9 @@ pub use dema::Dema;
 pub use demand_index::DemandIndex;
 pub use demark_pivots::{DemarkPivots, DemarkPivotsOutput};
 pub use depth_slope::DepthSlope;
+pub use derivative_oscillator::DerivativeOscillator;
 pub use detrended_std_dev::DetrendedStdDev;
+pub use disparity_index::DisparityIndex;
 pub use distance_ssd::DistanceSsd;
 pub use doji::Doji;
 pub use doji_star::DojiStar;
@@ -477,15 +584,22 @@ pub use dpo::Dpo;
 pub use dragonfly_doji::DragonflyDoji;
 pub use drawdown_duration::DrawdownDuration;
 pub use dx::Dx;
+pub use dynamic_momentum_index::DynamicMomentumIndex;
 pub use ease_of_movement::EaseOfMovement;
 pub use effective_spread::EffectiveSpread;
 pub use ehlers_stochastic::EhlersStochastic;
+pub use ehma::Ehma;
 pub use elder_impulse::ElderImpulse;
+pub use elder_ray::{ElderRay, ElderRayOutput};
+pub use elder_safezone::{ElderSafeZone, ElderSafeZoneOutput};
 pub use ema::Ema;
 pub use empirical_mode_decomposition::EmpiricalModeDecomposition;
 pub use engulfing::Engulfing;
+pub use even_better_sinewave::EvenBetterSinewave;
 pub use evening_doji_star::EveningDojiStar;
 pub use evwma::Evwma;
+pub use ewma_volatility::EwmaVolatility;
+pub use expectancy::Expectancy;
 pub use falling_three_methods::FallingThreeMethods;
 pub use fama::Fama;
 pub use fib_arcs::{FibArcs, FibArcsOutput};
@@ -497,6 +611,7 @@ pub use fib_projection::{FibProjection, FibProjectionOutput};
 pub use fib_retracement::{FibRetracement, FibRetracementOutput};
 pub use fib_time_zones::{FibTimeZones, FibTimeZonesOutput};
 pub use fibonacci_pivots::{FibonacciPivots, FibonacciPivotsOutput};
+pub use fisher_rsi::FisherRsi;
 pub use fisher_transform::FisherTransform;
 pub use flag_pennant::FlagPennant;
 pub use footprint::{Footprint, FootprintLevel, FootprintOutput};
@@ -509,8 +624,12 @@ pub use funding_rate_mean::FundingRateMean;
 pub use funding_rate_zscore::FundingRateZScore;
 pub use gain_loss_ratio::GainLossRatio;
 pub use gap_side_by_side_white::GapSideBySideWhite;
+pub use garch11::Garch11;
 pub use garman_klass::GarmanKlassVolatility;
 pub use gartley::Gartley;
+pub use gator_oscillator::{GatorOscillator, GatorOscillatorOutput};
+pub use generalized_dema::GeneralizedDema;
+pub use geometric_ma::GeometricMa;
 pub use golden_pocket::{GoldenPocket, GoldenPocketOutput};
 pub use granger_causality::GrangerCausality;
 pub use gravestone_doji::GravestoneDoji;
@@ -520,13 +639,16 @@ pub use harami::Harami;
 pub use head_and_shoulders::HeadAndShoulders;
 pub use heikin_ashi::{HeikinAshi, HeikinAshiOutput};
 pub use high_low_index::HighLowIndex;
+pub use high_low_range::HighLowRange;
 pub use high_wave::HighWave;
+pub use highpass_filter::HighpassFilter;
 pub use hikkake::Hikkake;
 pub use hikkake_modified::HikkakeModified;
 pub use hilbert_dominant_cycle::HilbertDominantCycle;
 pub use hilo_activator::HiLoActivator;
 pub use historical_volatility::HistoricalVolatility;
 pub use hma::Hma;
+pub use holt_winters::HoltWinters;
 pub use homing_pigeon::HomingPigeon;
 pub use ht_dcphase::HtDcPhase;
 pub use ht_phasor::{HtPhasor, HtPhasorOutput};
@@ -540,15 +662,22 @@ pub use inertia::Inertia;
 pub use information_ratio::InformationRatio;
 pub use initial_balance::{InitialBalance, InitialBalanceOutput};
 pub use instantaneous_trendline::InstantaneousTrendline;
+pub use intraday_intensity::IntradayIntensity;
+pub use intraday_momentum_index::IntradayMomentumIndex;
 pub use intraday_volatility_profile::{IntradayVolatilityProfile, IntradayVolatilityProfileOutput};
 pub use inverse_fisher_transform::InverseFisherTransform;
 pub use inverted_hammer::InvertedHammer;
+pub use jarque_bera::JarqueBera;
 pub use jma::Jma;
+pub use jump_indicator::JumpIndicator;
 pub use kagi_bars::{KagiBar, KagiBars};
 pub use kalman_hedge_ratio::{KalmanHedgeRatio, KalmanHedgeRatioOutput};
 pub use kama::Kama;
+pub use kase_devstop::{KaseDevStop, KaseDevStopOutput};
+pub use kase_permission_stochastic::{KasePermissionStochastic, KasePermissionStochasticOutput};
 pub use kelly_criterion::KellyCriterion;
 pub use keltner::{Keltner, KeltnerOutput};
+pub use kendall_tau::KendallTau;
 pub use kicking::Kicking;
 pub use kicking_by_length::KickingByLength;
 pub use kst::{Kst, KstOutput};
@@ -564,6 +693,7 @@ pub use linreg_channel::{LinRegChannel, LinRegChannelOutput};
 pub use linreg_intercept::LinRegIntercept;
 pub use linreg_slope::LinRegSlope;
 pub use liquidation_features::{LiquidationFeatures, LiquidationFeaturesOutput};
+pub use log_return::LogReturn;
 pub use long_legged_doji::LongLeggedDoji;
 pub use long_line::LongLine;
 pub use long_short_ratio::LongShortRatio;
@@ -571,6 +701,7 @@ pub use ma_envelope::{MaEnvelope, MaEnvelopeOutput};
 pub use macd::{MacdIndicator, MacdOutput};
 pub use macd_ext::{MaType, MacdExt};
 pub use macd_fix::MacdFix;
+pub use macd_histogram::MacdHistogram;
 pub use mama::{Mama, MamaOutput};
 pub use market_facilitation_index::MarketFacilitationIndex;
 pub use marubozu::Marubozu;
@@ -582,6 +713,8 @@ pub use mcclellan_oscillator::McClellanOscillator;
 pub use mcclellan_summation_index::McClellanSummationIndex;
 pub use mcginley_dynamic::McGinleyDynamic;
 pub use median_absolute_deviation::MedianAbsoluteDeviation;
+pub use median_channel::{MedianChannel, MedianChannelOutput};
+pub use median_ma::MedianMa;
 pub use median_price::MedianPrice;
 pub use mfi::Mfi;
 pub use microprice::Microprice;
@@ -589,11 +722,14 @@ pub use mid_point::MidPoint;
 pub use mid_price::MidPrice;
 pub use minus_di::MinusDi;
 pub use minus_dm::MinusDm;
+pub use modified_ma_stop::{ModifiedMaStop, ModifiedMaStopOutput};
 pub use mom::Mom;
 pub use morning_doji_star::MorningDojiStar;
 pub use morning_evening_star::MorningEveningStar;
+pub use murrey_math_lines::{MurreyMathLines, MurreyMathLinesOutput};
 pub use natr::Natr;
 pub use new_highs_new_lows::NewHighsNewLows;
+pub use nrtr::{Nrtr, NrtrOutput};
 pub use nvi::Nvi;
 pub use ob_imbalance_full::OrderBookImbalanceFull;
 pub use ob_imbalance_top1::OrderBookImbalanceTop1;
@@ -606,6 +742,7 @@ pub use omega_ratio::OmegaRatio;
 pub use on_neck::OnNeck;
 pub use opening_marubozu::OpeningMarubozu;
 pub use opening_range::{OpeningRange, OpeningRangeOutput};
+pub use order_flow_imbalance::OrderFlowImbalance;
 pub use ou_half_life::OuHalfLife;
 pub use overnight_gap::OvernightGap;
 pub use overnight_intraday_return::{OvernightIntradayReturn, OvernightIntradayReturnOutput};
@@ -619,48 +756,69 @@ pub use percent_b::PercentB;
 pub use percentage_trailing_stop::PercentageTrailingStop;
 pub use pgo::Pgo;
 pub use piercing_dark_cloud::PiercingDarkCloud;
+pub use pivot_reversal::PivotReversal;
 pub use plus_di::PlusDi;
 pub use plus_dm::PlusDm;
 pub use pmo::Pmo;
 pub use point_and_figure_bars::{PnfColumn, PointAndFigureBars};
+pub use polarized_fractal_efficiency::PolarizedFractalEfficiency;
 pub use ppo::Ppo;
+pub use ppo_histogram::PpoHistogram;
 pub use profit_factor::ProfitFactor;
+pub use projection_bands::{ProjectionBands, ProjectionBandsOutput};
+pub use projection_oscillator::ProjectionOscillator;
 pub use psar::Psar;
 pub use pvi::Pvi;
+pub use qqe::{Qqe, QqeOutput};
+pub use qstick::Qstick;
+pub use quartile_bands::{QuartileBands, QuartileBandsOutput};
 pub use quoted_spread::QuotedSpread;
 pub use r_squared::RSquared;
 pub use realized_spread::RealizedSpread;
+pub use realized_volatility::RealizedVolatility;
 pub use recovery_factor::RecoveryFactor;
 pub use rectangle_range::RectangleRange;
+pub use reflex::Reflex;
+pub use regime_label::RegimeLabel;
 pub use relative_strength_ab::{RelativeStrengthAB, RelativeStrengthOutput};
 pub use renko_bars::{RenkoBars, RenkoBrick};
 pub use renko_trailing_stop::RenkoTrailingStop;
 pub use rickshaw_man::RickshawMan;
 pub use rising_three_methods::RisingThreeMethods;
+pub use rmi::Rmi;
 pub use roc::Roc;
 pub use rocp::Rocp;
 pub use rocr::Rocr;
 pub use rocr100::Rocr100;
 pub use rogers_satchell::RogersSatchellVolatility;
+pub use roll_measure::RollMeasure;
 pub use rolling_correlation::RollingCorrelation;
 pub use rolling_covariance::RollingCovariance;
+pub use rolling_iqr::RollingIqr;
+pub use rolling_min_max_scaler::RollingMinMaxScaler;
+pub use rolling_percentile_rank::RollingPercentileRank;
+pub use rolling_quantile::RollingQuantile;
 pub use roofing_filter::RoofingFilter;
 pub use rsi::Rsi;
+pub use rsx::Rsx;
 pub use rvi::Rvi;
 pub use rvi_volatility::RviVolatility;
 pub use rwi::{Rwi, RwiOutput};
+pub use sample_entropy::SampleEntropy;
 pub use sar_ext::SarExt;
 pub use seasonal_z_score::SeasonalZScore;
 pub use separating_lines::SeparatingLines;
 pub use session_high_low::{SessionHighLow, SessionHighLowOutput};
 pub use session_range::{SessionRange, SessionRangeOutput};
 pub use session_vwap::SessionVwap;
+pub use shannon_entropy::ShannonEntropy;
 pub use shark::Shark;
 pub use sharpe_ratio::SharpeRatio;
 pub use shooting_star::ShootingStar;
 pub use short_line::ShortLine;
 pub use signed_volume::SignedVolume;
 pub use sine_wave::SineWave;
+pub use sine_weighted_ma::SineWeightedMa;
 pub use skewness::Skewness;
 pub use sma::Sma;
 pub use smi::Smi;
@@ -668,6 +826,7 @@ pub use smma::Smma;
 pub use sortino_ratio::SortinoRatio;
 pub use spearman_correlation::SpearmanCorrelation;
 pub use spinning_top::SpinningTop;
+pub use spread_ar1_coefficient::SpreadAr1Coefficient;
 pub use spread_bollinger_bands::{SpreadBollingerBands, SpreadBollingerBandsOutput};
 pub use spread_hurst::SpreadHurst;
 pub use stalled_pattern::StalledPattern;
@@ -680,6 +839,7 @@ pub use step_trailing_stop::StepTrailingStop;
 pub use stick_sandwich::StickSandwich;
 pub use stoch_rsi::StochRsi;
 pub use stochastic::{Stochastic, StochasticOutput};
+pub use stochastic_cci::StochasticCci;
 pub use super_smoother::SuperSmoother;
 pub use super_trend::{SuperTrend, SuperTrendOutput};
 pub use t3::T3;
@@ -709,9 +869,14 @@ pub use three_stars_in_south::ThreeStarsInSouth;
 pub use thrusting::Thrusting;
 pub use tick_index::TickIndex;
 pub use tii::Tii;
+pub use time_based_stop::TimeBasedStop;
 pub use time_of_day_return_profile::{TimeOfDayReturnProfile, TimeOfDayReturnProfileOutput};
 pub use tpo_profile::{TpoProfile, TpoProfileOutput};
 pub use trade_imbalance::TradeImbalance;
+pub use trade_volume_index::TradeVolumeIndex;
+pub use trend_label::TrendLabel;
+pub use trend_strength_index::TrendStrengthIndex;
+pub use trendflex::Trendflex;
 pub use treynor_ratio::TreynorRatio;
 pub use triangle::Triangle;
 pub use trima::Trima;
@@ -720,16 +885,20 @@ pub use triple_top_bottom::TripleTopBottom;
 pub use trix::Trix;
 pub use true_range::TrueRange;
 pub use tsf::Tsf;
+pub use tsf_oscillator::TsfOscillator;
 pub use tsi::Tsi;
 pub use tsv::Tsv;
 pub use ttm_squeeze::{TtmSqueeze, TtmSqueezeOutput};
+pub use ttm_trend::TtmTrend;
 pub use turn_of_month::TurnOfMonth;
 pub use tweezer::Tweezer;
+pub use twiggs_money_flow::TwiggsMoneyFlow;
 pub use two_crows::TwoCrows;
 pub use typical_price::TypicalPrice;
 pub use ulcer_index::UlcerIndex;
 pub use ultimate_oscillator::UltimateOscillator;
 pub use unique_three_river::UniqueThreeRiver;
+pub use universal_oscillator::UniversalOscillator;
 pub use up_down_volume_ratio::UpDownVolumeRatio;
 pub use upside_gap_three_methods::UpsideGapThreeMethods;
 pub use upside_gap_two_crows::UpsideGapTwoCrows;
@@ -739,21 +908,32 @@ pub use variance::Variance;
 pub use variance_ratio::VarianceRatio;
 pub use vertical_horizontal_filter::VerticalHorizontalFilter;
 pub use vidya::Vidya;
+pub use volatility_cone::{VolatilityCone, VolatilityConeOutput};
+pub use volatility_of_volatility::VolatilityOfVolatility;
+pub use volatility_ratio::VolatilityRatio;
 pub use volty_stop::VoltyStop;
 pub use volume_by_time_profile::{VolumeByTimeProfile, VolumeByTimeProfileOutput};
 pub use volume_oscillator::VolumeOscillator;
 pub use volume_profile::{VolumeProfile, VolumeProfileOutput};
+pub use volume_rsi::VolumeRsi;
+pub use volume_weighted_macd::{VolumeWeightedMacd, VolumeWeightedMacdOutput};
+pub use volume_weighted_sr::{VolumeWeightedSr, VolumeWeightedSrOutput};
 pub use vortex::{Vortex, VortexOutput};
+pub use vpin::Vpin;
 pub use vpt::VolumePriceTrend;
 pub use vwap::{RollingVwap, Vwap};
 pub use vwap_stddev_bands::{VwapStdDevBands, VwapStdDevBandsOutput};
 pub use vwma::Vwma;
 pub use vzo::Vzo;
+pub use wad::Wad;
+pub use wave_pm::WavePm;
 pub use wave_trend::{WaveTrend, WaveTrendOutput};
 pub use wedge::Wedge;
 pub use weighted_close::WeightedClose;
+pub use wick_ratio::WickRatio;
 pub use williams_fractals::{WilliamsFractals, WilliamsFractalsOutput};
 pub use williams_r::WilliamsR;
+pub use win_rate::WinRate;
 pub use wma::Wma;
 pub use woodie_pivots::{WoodiePivots, WoodiePivotsOutput};
 pub use yang_zhang::YangZhangVolatility;
@@ -792,6 +972,13 @@ pub const FAMILIES: &[(&str, &[&str])] = &[
            "Jma",
            "Alligator",
            "Evwma",
+            "SineWeightedMa",
+            "GeometricMa",
+            "Ehma",
+            "MedianMa",
+            "AdaptiveLaguerreFilter",
+            "GeneralizedDema",
+            "HoltWinters",
        ],
    ),
    (
@@ -821,6 +1008,16 @@ pub const FAMILIES: &[(&str, &[&str])] = &[
            "Rocp",
            "Rocr",
            "Rocr100",
+            "DisparityIndex",
+            "FisherRsi",
+            "Rsx",
+            "DynamicMomentumIndex",
+            "StochasticCci",
+            "Rmi",
+            "DerivativeOscillator",
+            "ElderRay",
+            "IntradayMomentumIndex",
+            "Qqe",
        ],
    ),
    (
@@ -846,6 +1043,14 @@ pub const FAMILIES: &[(&str, &[&str])] = &[
            "PlusDi",
            "MinusDi",
            "Dx",
+            "TrendLabel",
+            "TtmTrend",
+            "TrendStrengthIndex",
+            "Qstick",
+            "PolarizedFractalEfficiency",
+            "WavePm",
+            "GatorOscillator",
+            "KasePermissionStochastic",
        ],
    ),
    (
@@ -862,6 +1067,9 @@ pub const FAMILIES: &[(&str, &[&str])] = &[
            "ZeroLagMacd",
            "ElderImpulse",
            "Stc",
+            "TsfOscillator",
+            "MacdHistogram",
+            "PpoHistogram",
        ],
    ),
    (
@@ -884,6 +1092,14 @@ pub const FAMILIES: &[(&str, &[&str])] = &[
            "GarmanKlassVolatility",
            "RogersSatchellVolatility",
            "YangZhangVolatility",
+            "JumpIndicator",
+            "RegimeLabel",
+            "EwmaVolatility",
+            "Garch11",
+            "VolatilityOfVolatility",
+            "BipowerVariation",
+            "VolatilityRatio",
+            "VolatilityCone",
        ],
    ),
    (
@@ -900,6 +1116,11 @@ pub const FAMILIES: &[(&str, &[&str])] = &[
            "TtmSqueeze",
            "FractalChaosBands",
            "VwapStdDevBands",
+            "QuartileBands",
+            "BomarBands",
+            "MedianChannel",
+            "ProjectionBands",
+            "ProjectionOscillator",
        ],
    ),
    (
@@ -918,6 +1139,12 @@ pub const FAMILIES: &[(&str, &[&str])] = &[
            "StepTrailingStop",
            "RenkoTrailingStop",
            "SarExt",
+            "KaseDevStop",
+            "ElderSafeZone",
+            "AtrRatchet",
+            "Nrtr",
+            "TimeBasedStop",
+            "ModifiedMaStop",
        ],
    ),
    (
@@ -942,6 +1169,13 @@ pub const FAMILIES: &[(&str, &[&str])] = &[
            "Tsv",
            "Vzo",
            "MarketFacilitationIndex",
+            "VolumeRsi",
+            "Wad",
+            "TwiggsMoneyFlow",
+            "TradeVolumeIndex",
+            "IntradayIntensity",
+            "BetterVolume",
+            "VolumeWeightedMacd",
        ],
    ),
    (
@@ -987,6 +1221,21 @@ pub const FAMILIES: &[(&str, &[&str])] = &[
            "GrangerCausality",
            "KalmanHedgeRatio",
            "SpreadBollingerBands",
+            "LogReturn",
+            "RealizedVolatility",
+            "RollingIqr",
+            "RollingPercentileRank",
+            "RollingQuantile",
+            "SpreadAr1Coefficient",
+            "CloseVsOpen",
+            "BodySizePct",
+            "WickRatio",
+            "HighLowRange",
+            "JarqueBera",
+            "RollingMinMaxScaler",
+            "ShannonEntropy",
+            "SampleEntropy",
+            "KendallTau",
        ],
    ),
    (
@@ -1011,6 +1260,16 @@ pub const FAMILIES: &[(&str, &[&str])] = &[
            "EmpiricalModeDecomposition",
            "EhlersStochastic",
            "InstantaneousTrendline",
+            "HighpassFilter",
+            "Reflex",
+            "Trendflex",
+            "CorrelationTrendIndicator",
+            "AdaptiveRsi",
+            "UniversalOscillator",
+            "AdaptiveCci",
+            "BandpassFilter",
+            "EvenBetterSinewave",
+            "AutocorrelationPeriodogram",
        ],
    ),
    (
@@ -1023,6 +1282,11 @@ pub const FAMILIES: &[(&str, &[&str])] = &[
            "DemarkPivots",
            "WilliamsFractals",
            "ZigZag",
+            "CentralPivotRange",
+            "MurreyMathLines",
+            "AndrewsPitchfork",
+            "VolumeWeightedSr",
+            "PivotReversal",
        ],
    ),
    (
@@ -1124,6 +1388,10 @@ pub const FAMILIES: &[(&str, &[&str])] = &[
            "RealizedSpread",
            "KylesLambda",
            "Footprint",
+            "OrderFlowImbalance",
+            "Vpin",
+            "AmihudIlliquidity",
+            "RollMeasure",
        ],
    ),
    (
@@ -1173,6 +1441,8 @@ pub const FAMILIES: &[(&str, &[&str])] = &[
            "TreynorRatio",
            "InformationRatio",
            "Alpha",
+            "WinRate",
+            "Expectancy",
        ],
    ),
    (
@@ -1285,6 +1555,6 @@ mod family_tests {
        // the actual indicator count is the early-warning signal that an
        // indicator was added without being assigned a family.
        let total: usize = FAMILIES.iter().map(|(_, ns)| ns.len()).sum();
-        assert_eq!(total, 377, "FAMILIES total drifted from indicator count");
+        assert_eq!(total, 467, "FAMILIES total drifted from indicator count");
    }
 }
@@ -0,0 +1,238 @@
+//! Modified-MA Stop — a trailing stop riding the Modified Moving Average (SMMA).
+
+use crate::error::{Error, Result};
+use crate::indicators::smma::Smma;
+use crate::ohlcv::Candle;
+use crate::traits::Indicator;
+
+/// Output of [`ModifiedMaStop`]: the active stop level and the trend direction.
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub struct ModifiedMaStopOutput {
+    /// The stop level (a directionally-ratcheted Modified Moving Average).
+    pub value: f64,
+    /// Trend direction: `+1.0` long (stop below price), `-1.0` short.
+    pub direction: f64,
+}
+
+/// Modified-MA Stop — a trailing stop whose line is the **Modified Moving
+/// Average** (SMMA / Wilder's RMA) of price, allowed to move only in the trend's
+/// favour.
+///
+/// ```text
+/// ma = SMMA(close, period)                 (Modified Moving Average)
+/// long:  stop = max(prev_stop, ma);  flip short when close < stop
+/// short: stop = min(prev_stop, ma);  flip long  when close > stop
+/// ```
+///
+/// The Modified Moving Average (also called the smoothed or running moving
+/// average) is the slow, low-lag average Wilder used throughout his systems. Using
+/// it directly as a trailing line — but **ratcheting** so the long stop never
+/// falls and the short stop never rises — turns the smooth average into a stop
+/// that hugs price in a trend and flips when price decisively crosses it. Because
+/// the SMMA lags, the stop gives trends room while still exiting clean reversals.
+///
+/// The first stop lands once the SMMA is ready (`period` inputs). Each `update` is
+/// O(1).
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Candle, Indicator, ModifiedMaStop};
+///
+/// let mut indicator = ModifiedMaStop::new(14).unwrap();
+/// let mut last = None;
+/// for i in 0..60 {
+///     let base = 100.0 + f64::from(i);
+///     let c = Candle::new(base, base + 1.0, base - 1.0, base + 0.5, 1_000.0, 0).unwrap();
+///     last = indicator.update(c);
+/// }
+/// assert!(last.is_some());
+/// ```
+#[derive(Debug, Clone)]
+pub struct ModifiedMaStop {
+    smma: Smma,
+    period: usize,
+    direction: f64,
+    stop: f64,
+    last: Option<ModifiedMaStopOutput>,
+}
+
+impl ModifiedMaStop {
+    /// Construct a Modified-MA stop with the given SMMA `period`.
+    ///
+    /// # Errors
+    ///
+    /// Returns [`Error::PeriodZero`] if `period == 0`.
+    pub fn new(period: usize) -> Result<Self> {
+        if period == 0 {
+            return Err(Error::PeriodZero);
+        }
+        Ok(Self {
+            smma: Smma::new(period)?,
+            period,
+            direction: 0.0,
+            stop: 0.0,
+            last: None,
+        })
+    }
+
+    /// Configured SMMA period.
+    pub const fn period(&self) -> usize {
+        self.period
+    }
+
+    /// Current value if available.
+    pub const fn value(&self) -> Option<ModifiedMaStopOutput> {
+        self.last
+    }
+}
+
+impl Indicator for ModifiedMaStop {
+    type Input = Candle;
+    type Output = ModifiedMaStopOutput;
+
+    fn update(&mut self, candle: Candle) -> Option<ModifiedMaStopOutput> {
+        let ma = self.smma.update(candle.close)?;
+        let close = candle.close;
+
+        if self.direction == 0.0 {
+            self.direction = if close >= ma { 1.0 } else { -1.0 };
+            self.stop = ma;
+        } else if self.direction > 0.0 {
+            self.stop = self.stop.max(ma);
+            if close < self.stop {
+                self.direction = -1.0;
+                self.stop = ma;
+            }
+        } else {
+            self.stop = self.stop.min(ma);
+            if close > self.stop {
+                self.direction = 1.0;
+                self.stop = ma;
+            }
+        }
+
+        let out = ModifiedMaStopOutput {
+            value: self.stop,
+            direction: self.direction,
+        };
+        self.last = Some(out);
+        Some(out)
+    }
+
+    fn reset(&mut self) {
+        self.smma.reset();
+        self.direction = 0.0;
+        self.stop = 0.0;
+        self.last = None;
+    }
+
+    fn warmup_period(&self) -> usize {
+        self.period
+    }
+
+    fn is_ready(&self) -> bool {
+        self.last.is_some()
+    }
+
+    fn name(&self) -> &'static str {
+        "ModifiedMaStop"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+
+    fn c(close: f64) -> Candle {
+        Candle::new_unchecked(close, close + 1.0, close - 1.0, close, 1_000.0, 0)
+    }
+
+    #[test]
+    fn rejects_zero_period() {
+        assert!(matches!(ModifiedMaStop::new(0), Err(Error::PeriodZero)));
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let m = ModifiedMaStop::new(14).unwrap();
+        assert_eq!(m.period(), 14);
+        assert_eq!(m.warmup_period(), 14);
+        assert_eq!(m.name(), "ModifiedMaStop");
+        assert!(!m.is_ready());
+        assert_eq!(m.value(), None);
+    }
+
+    #[test]
+    fn first_emission_at_warmup_period() {
+        let mut m = ModifiedMaStop::new(5).unwrap();
+        let candles: Vec<Candle> = (0..12).map(|i| c(100.0 + f64::from(i))).collect();
+        let out = m.batch(&candles);
+        for v in out.iter().take(4) {
+            assert!(v.is_none());
+        }
+        assert!(out[4].is_some());
+    }
+
+    #[test]
+    fn uptrend_keeps_stop_below_price() {
+        let mut m = ModifiedMaStop::new(5).unwrap();
+        let candles: Vec<Candle> = (0..60).map(|i| c(100.0 + 2.0 * f64::from(i))).collect();
+        for (o, candle) in m.batch(&candles).into_iter().zip(candles.iter()) {
+            if let Some(o) = o {
+                assert_eq!(o.direction, 1.0);
+                assert!(o.value < candle.close);
+            }
+        }
+    }
+
+    #[test]
+    fn long_stop_ratchets_up() {
+        let mut m = ModifiedMaStop::new(5).unwrap();
+        let candles: Vec<Candle> = (0..60).map(|i| c(100.0 + 2.0 * f64::from(i))).collect();
+        let mut prev = f64::NEG_INFINITY;
+        for o in m.batch(&candles).into_iter().flatten() {
+            assert_eq!(o.direction, 1.0, "pure uptrend stays long");
+            assert!(o.value >= prev, "long stop must not fall");
+            prev = o.value;
+        }
+    }
+
+    #[test]
+    fn flips_on_reversal() {
+        let mut candles: Vec<Candle> = (0..40).map(|i| c(100.0 + f64::from(i))).collect();
+        candles.extend((0..40).map(|i| c(140.0 - f64::from(i))));
+        let mut m = ModifiedMaStop::new(5).unwrap();
+        let dirs: Vec<f64> = m
+            .batch(&candles)
+            .into_iter()
+            .flatten()
+            .map(|o| o.direction)
+            .collect();
+        assert!(dirs.iter().any(|&d| d > 0.0));
+        assert!(dirs.iter().any(|&d| d < 0.0));
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut m = ModifiedMaStop::new(5).unwrap();
+        m.batch(&(0..40).map(|i| c(100.0 + f64::from(i))).collect::<Vec<_>>());
+        assert!(m.is_ready());
+        m.reset();
+        assert!(!m.is_ready());
+        assert_eq!(m.value(), None);
+        assert_eq!(m.update(c(100.0)), None);
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let candles: Vec<Candle> = (0..120)
+            .map(|i| c(100.0 + (f64::from(i) * 0.25).sin() * 9.0))
+            .collect();
+        let batch = ModifiedMaStop::new(14).unwrap().batch(&candles);
+        let mut b = ModifiedMaStop::new(14).unwrap();
+        let streamed: Vec<_> = candles.iter().map(|c| b.update(*c)).collect();
+        assert_eq!(batch, streamed);
+    }
+}
@@ -0,0 +1,272 @@
+//! Murrey Math Lines — the eighths grid over the recent trading range.
+
+use std::collections::VecDeque;
+
+use crate::error::{Error, Result};
+use crate::ohlcv::Candle;
+use crate::traits::Indicator;
+
+/// Output of [`MurreyMathLines`]: the nine Murrey Math levels from the bottom
+/// (`mm0_8`, ultimate support) to the top (`mm8_8`, ultimate resistance).
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub struct MurreyMathLinesOutput {
+    /// 8/8 — ultimate resistance (top of the frame).
+    pub mm8_8: f64,
+    /// 7/8 — "weak, stall and reverse" (overbought).
+    pub mm7_8: f64,
+    /// 6/8 — upper pivot / reversal line.
+    pub mm6_8: f64,
+    /// 5/8 — top of the normal trading range.
+    pub mm5_8: f64,
+    /// 4/8 — the major pivot (mean) line.
+    pub mm4_8: f64,
+    /// 3/8 — bottom of the normal trading range.
+    pub mm3_8: f64,
+    /// 2/8 — lower pivot / reversal line.
+    pub mm2_8: f64,
+    /// 1/8 — "weak, stall and reverse" (oversold).
+    pub mm1_8: f64,
+    /// 0/8 — ultimate support (bottom of the frame).
+    pub mm0_8: f64,
+}
+
+/// Murrey Math Lines — T. H. Murrey's grid that divides the recent trading range
+/// into eighths, each acting as support/resistance.
+///
+/// ```text
+/// HH = highest high over `period`,  LL = lowest low over `period`
+/// step = (HH − LL) / 8
+/// mm{i}_8 = LL + i · step       for i = 0..8
+/// ```
+///
+/// Murrey Math (a Gann-derived framework) holds that price gravitates to and
+/// reverses at the eighth divisions of its range. The **4/8** line is the major
+/// pivot (mean); **0/8** and **8/8** are the strongest support and resistance;
+/// **3/8** and **5/8** bound the "normal" trading range, while **1/8**/**7/8** are
+/// the weak "stall and reverse" lines. This implementation uses the price-derived
+/// eighths over a rolling high-low frame (the practical core of the method) rather
+/// than Murrey's full octave-quantised frame sizing, so the levels track the
+/// instrument's actual recent range.
+///
+/// The first value lands after `period` inputs; each `update` rescans the frame in
+/// O(`period`). A degenerate flat frame (`HH == LL`) collapses every line onto the
+/// price.
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Candle, Indicator, MurreyMathLines};
+///
+/// let mut indicator = MurreyMathLines::new(64).unwrap();
+/// let mut last = None;
+/// for i in 0..120 {
+///     let base = 100.0 + (f64::from(i) * 0.3).sin() * 10.0;
+///     let c = Candle::new(base, base + 1.0, base - 1.0, base, 1_000.0, 0).unwrap();
+///     last = indicator.update(c);
+/// }
+/// assert!(last.is_some());
+/// ```
+#[derive(Debug, Clone)]
+pub struct MurreyMathLines {
+    period: usize,
+    highs: VecDeque<f64>,
+    lows: VecDeque<f64>,
+    last: Option<MurreyMathLinesOutput>,
+}
+
+impl MurreyMathLines {
+    /// Construct Murrey Math Lines over a `period`-bar high-low frame.
+    ///
+    /// # Errors
+    ///
+    /// Returns [`Error::PeriodZero`] if `period == 0`.
+    pub fn new(period: usize) -> Result<Self> {
+        if period == 0 {
+            return Err(Error::PeriodZero);
+        }
+        Ok(Self {
+            period,
+            highs: VecDeque::with_capacity(period),
+            lows: VecDeque::with_capacity(period),
+            last: None,
+        })
+    }
+
+    /// Configured frame period.
+    pub const fn period(&self) -> usize {
+        self.period
+    }
+
+    /// Current value if available.
+    pub const fn value(&self) -> Option<MurreyMathLinesOutput> {
+        self.last
+    }
+}
+
+impl Indicator for MurreyMathLines {
+    type Input = Candle;
+    type Output = MurreyMathLinesOutput;
+
+    fn update(&mut self, candle: Candle) -> Option<MurreyMathLinesOutput> {
+        if self.highs.len() == self.period {
+            self.highs.pop_front();
+            self.lows.pop_front();
+        }
+        self.highs.push_back(candle.high);
+        self.lows.push_back(candle.low);
+        if self.highs.len() < self.period {
+            return None;
+        }
+        let hh = self.highs.iter().copied().fold(f64::NEG_INFINITY, f64::max);
+        let ll = self.lows.iter().copied().fold(f64::INFINITY, f64::min);
+        let step = (hh - ll) / 8.0;
+        let level = |i: f64| ll + i * step;
+        let out = MurreyMathLinesOutput {
+            mm0_8: level(0.0),
+            mm1_8: level(1.0),
+            mm2_8: level(2.0),
+            mm3_8: level(3.0),
+            mm4_8: level(4.0),
+            mm5_8: level(5.0),
+            mm6_8: level(6.0),
+            mm7_8: level(7.0),
+            mm8_8: level(8.0),
+        };
+        self.last = Some(out);
+        Some(out)
+    }
+
+    fn reset(&mut self) {
+        self.highs.clear();
+        self.lows.clear();
+        self.last = None;
+    }
+
+    fn warmup_period(&self) -> usize {
+        self.period
+    }
+
+    fn is_ready(&self) -> bool {
+        self.last.is_some()
+    }
+
+    fn name(&self) -> &'static str {
+        "MurreyMathLines"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    fn c(high: f64, low: f64) -> Candle {
+        Candle::new_unchecked(low, high, low, f64::midpoint(high, low), 1_000.0, 0)
+    }
+
+    #[test]
+    fn rejects_zero_period() {
+        assert!(matches!(MurreyMathLines::new(0), Err(Error::PeriodZero)));
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let m = MurreyMathLines::new(64).unwrap();
+        assert_eq!(m.period(), 64);
+        assert_eq!(m.warmup_period(), 64);
+        assert_eq!(m.name(), "MurreyMathLines");
+        assert!(!m.is_ready());
+        assert_eq!(m.value(), None);
+    }
+
+    #[test]
+    fn first_emission_at_warmup_period() {
+        let mut m = MurreyMathLines::new(4).unwrap();
+        let candles: Vec<Candle> = (0..6)
+            .map(|i| c(101.0 + f64::from(i), 99.0 + f64::from(i)))
+            .collect();
+        let out = m.batch(&candles);
+        for v in out.iter().take(3) {
+            assert!(v.is_none());
+        }
+        assert!(out[3].is_some());
+    }
+
+    #[test]
+    fn eighths_are_evenly_spaced() {
+        // Frame [100, 180] over the window -> step = 10.
+        let mut m = MurreyMathLines::new(2).unwrap();
+        let out = m
+            .batch(&[c(180.0, 100.0), c(180.0, 100.0)])
+            .into_iter()
+            .flatten()
+            .last()
+            .unwrap();
+        assert_relative_eq!(out.mm0_8, 100.0, epsilon = 1e-9);
+        assert_relative_eq!(out.mm4_8, 140.0, epsilon = 1e-9);
+        assert_relative_eq!(out.mm8_8, 180.0, epsilon = 1e-9);
+        assert_relative_eq!(out.mm1_8 - out.mm0_8, 10.0, epsilon = 1e-9);
+    }
+
+    #[test]
+    fn levels_are_ordered() {
+        let mut m = MurreyMathLines::new(10).unwrap();
+        let candles: Vec<Candle> = (0..30)
+            .map(|i| {
+                c(
+                    110.0 + (f64::from(i) * 0.3).sin() * 8.0,
+                    90.0 + (f64::from(i) * 0.3).cos() * 8.0,
+                )
+            })
+            .collect();
+        for o in m.batch(&candles).into_iter().flatten() {
+            assert!(o.mm0_8 <= o.mm4_8 && o.mm4_8 <= o.mm8_8);
+            assert!(o.mm3_8 <= o.mm5_8);
+        }
+    }
+
+    #[test]
+    fn flat_frame_collapses() {
+        let mut m = MurreyMathLines::new(3).unwrap();
+        let out = m
+            .batch(&[c(50.0, 50.0), c(50.0, 50.0), c(50.0, 50.0)])
+            .into_iter()
+            .flatten()
+            .last()
+            .unwrap();
+        assert_relative_eq!(out.mm0_8, 50.0, epsilon = 1e-12);
+        assert_relative_eq!(out.mm8_8, 50.0, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut m = MurreyMathLines::new(4).unwrap();
+        m.batch(
+            &(0..6)
+                .map(|i| c(101.0 + f64::from(i), 99.0 + f64::from(i)))
+                .collect::<Vec<_>>(),
+        );
+        assert!(m.is_ready());
+        m.reset();
+        assert!(!m.is_ready());
+        assert_eq!(m.value(), None);
+        assert_eq!(m.update(c(101.0, 99.0)), None);
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let candles: Vec<Candle> = (0..120)
+            .map(|i| {
+                c(
+                    110.0 + (f64::from(i) * 0.25).sin() * 9.0,
+                    90.0 + (f64::from(i) * 0.25).cos() * 9.0,
+                )
+            })
+            .collect();
+        let batch = MurreyMathLines::new(64).unwrap().batch(&candles);
+        let mut b = MurreyMathLines::new(64).unwrap();
+        let streamed: Vec<_> = candles.iter().map(|x| b.update(*x)).collect();
+        assert_eq!(batch, streamed);
+    }
+}
@@ -0,0 +1,259 @@
+//! NRTR — Nick Rypock Trailing Reverse, a percentage trailing-reverse stop.
+
+use crate::error::{Error, Result};
+use crate::ohlcv::Candle;
+use crate::traits::Indicator;
+
+/// Output of [`Nrtr`]: the trailing-reverse line and the trend direction.
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub struct NrtrOutput {
+    /// The NRTR line — below price in an uptrend, above price in a downtrend.
+    pub value: f64,
+    /// Trend direction: `+1.0` up (line below price), `-1.0` down.
+    pub direction: f64,
+}
+
+/// NRTR (Nick Rypock Trailing Reverse) — a **percentage** trailing-reverse stop
+/// that follows the trend extreme and flips when price retraces by a fixed
+/// percentage.
+///
+/// ```text
+/// uptrend:   high_water = max(high_water, close)
+///            line       = high_water · (1 − pct/100)
+///            flip down when close < line  (reseed low_water = close)
+/// downtrend: low_water  = min(low_water, close)
+///            line       = low_water · (1 + pct/100)
+///            flip up   when close > line  (reseed high_water = close)
+/// ```
+///
+/// Unlike volatility stops (ATR, σ-of-range), NRTR uses a pure **percentage**
+/// retracement: the line trails the highest close reached in the up-leg at a
+/// fixed `pct` below it, and a close that gives back that percentage reverses the
+/// trend, handing the line to the opposite extreme. This makes it scale-free and
+/// trivially tunable — one number sets how much retracement you tolerate. It
+/// differs from a fixed percentage *stop-loss* in that it **reverses** (tracks
+/// both directions) rather than just exiting.
+///
+/// The first bar seeds the up-trend and emits a line immediately. Each `update` is
+/// O(1).
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Candle, Indicator, Nrtr};
+///
+/// let mut indicator = Nrtr::new(2.0).unwrap();
+/// let mut last = None;
+/// for i in 0..40 {
+///     let close = 100.0 + f64::from(i);
+///     let c = Candle::new(close, close + 0.5, close - 0.5, close, 1_000.0, 0).unwrap();
+///     last = indicator.update(c);
+/// }
+/// assert!(last.is_some());
+/// ```
+#[derive(Debug, Clone)]
+pub struct Nrtr {
+    pct: f64,
+    direction: f64,
+    water: f64,
+    last: Option<NrtrOutput>,
+}
+
+impl Nrtr {
+    /// Construct an NRTR with the given trailing percentage (e.g. `2.0` for 2%).
+    ///
+    /// # Errors
+    ///
+    /// Returns [`Error::InvalidParameter`] if `pct` is not finite or is outside
+    /// `(0, 100)`.
+    pub fn new(pct: f64) -> Result<Self> {
+        if !pct.is_finite() || pct <= 0.0 || pct >= 100.0 {
+            return Err(Error::InvalidParameter {
+                message: "NRTR percentage must be in (0, 100)",
+            });
+        }
+        Ok(Self {
+            pct,
+            direction: 0.0,
+            water: 0.0,
+            last: None,
+        })
+    }
+
+    /// Configured trailing percentage.
+    pub const fn pct(&self) -> f64 {
+        self.pct
+    }
+
+    /// Current value if available.
+    pub const fn value(&self) -> Option<NrtrOutput> {
+        self.last
+    }
+}
+
+impl Indicator for Nrtr {
+    type Input = Candle;
+    type Output = NrtrOutput;
+
+    fn update(&mut self, candle: Candle) -> Option<NrtrOutput> {
+        let close = candle.close;
+        let down = self.pct / 100.0;
+        let up = self.pct / 100.0;
+
+        if self.direction == 0.0 {
+            self.direction = 1.0;
+            self.water = close;
+        } else if self.direction > 0.0 {
+            self.water = self.water.max(close);
+            let line = self.water * (1.0 - down);
+            if close < line {
+                self.direction = -1.0;
+                self.water = close;
+            }
+        } else {
+            self.water = self.water.min(close);
+            let line = self.water * (1.0 + up);
+            if close > line {
+                self.direction = 1.0;
+                self.water = close;
+            }
+        }
+
+        let line = if self.direction > 0.0 {
+            self.water * (1.0 - down)
+        } else {
+            self.water * (1.0 + up)
+        };
+        let out = NrtrOutput {
+            value: line,
+            direction: self.direction,
+        };
+        self.last = Some(out);
+        Some(out)
+    }
+
+    fn reset(&mut self) {
+        self.direction = 0.0;
+        self.water = 0.0;
+        self.last = None;
+    }
+
+    fn warmup_period(&self) -> usize {
+        1
+    }
+
+    fn is_ready(&self) -> bool {
+        self.last.is_some()
+    }
+
+    fn name(&self) -> &'static str {
+        "Nrtr"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+
+    fn c(close: f64) -> Candle {
+        Candle::new_unchecked(close, close, close, close, 1_000.0, 0)
+    }
+
+    #[test]
+    fn rejects_invalid_pct() {
+        assert!(matches!(
+            Nrtr::new(0.0),
+            Err(Error::InvalidParameter { .. })
+        ));
+        assert!(matches!(
+            Nrtr::new(100.0),
+            Err(Error::InvalidParameter { .. })
+        ));
+        assert!(matches!(
+            Nrtr::new(f64::NAN),
+            Err(Error::InvalidParameter { .. })
+        ));
+        assert!(Nrtr::new(2.0).is_ok());
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let n = Nrtr::new(2.0).unwrap();
+        assert_eq!(n.pct(), 2.0);
+        assert_eq!(n.warmup_period(), 1);
+        assert_eq!(n.name(), "Nrtr");
+        assert!(!n.is_ready());
+        assert_eq!(n.value(), None);
+    }
+
+    #[test]
+    fn first_bar_emits_up_line() {
+        let mut n = Nrtr::new(10.0).unwrap();
+        let o = n.update(c(100.0)).unwrap();
+        assert_eq!(o.direction, 1.0);
+        // line = 100 * (1 - 0.10) = 90.
+        assert!((o.value - 90.0).abs() < 1e-9);
+    }
+
+    #[test]
+    fn uptrend_keeps_line_below_price() {
+        let mut n = Nrtr::new(5.0).unwrap();
+        let candles: Vec<Candle> = (0..40).map(|i| c(100.0 + f64::from(i))).collect();
+        for (o, candle) in n.batch(&candles).into_iter().zip(candles.iter()) {
+            let o = o.unwrap();
+            assert_eq!(o.direction, 1.0);
+            assert!(o.value < candle.close);
+        }
+    }
+
+    #[test]
+    fn reverses_on_retracement() {
+        let mut n = Nrtr::new(5.0).unwrap();
+        // Rise to 120, then drop sharply -> a >5% retracement reverses the trend.
+        let mut candles: Vec<Candle> = (0..20).map(|i| c(100.0 + f64::from(i))).collect();
+        candles.extend((0..10).map(|i| c(119.0 - 3.0 * f64::from(i))));
+        let dirs: Vec<f64> = n
+            .batch(&candles)
+            .into_iter()
+            .flatten()
+            .map(|o| o.direction)
+            .collect();
+        assert!(dirs.iter().any(|&d| d > 0.0));
+        assert!(dirs.iter().any(|&d| d < 0.0));
+    }
+
+    #[test]
+    fn downtrend_keeps_line_above_price() {
+        let mut n = Nrtr::new(5.0).unwrap();
+        // Establish a downtrend after an initial bar.
+        let mut candles = vec![c(100.0)];
+        candles.extend((0..30).map(|i| c(80.0 - f64::from(i))));
+        let out = n.batch(&candles);
+        let o = out.last().unwrap().unwrap();
+        let candle = candles.last().unwrap();
+        assert_eq!(o.direction, -1.0);
+        assert!(o.value > candle.close);
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut n = Nrtr::new(2.0).unwrap();
+        n.batch(&(0..20).map(|i| c(100.0 + f64::from(i))).collect::<Vec<_>>());
+        assert!(n.is_ready());
+        n.reset();
+        assert!(!n.is_ready());
+        assert_eq!(n.value(), None);
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let candles: Vec<Candle> = (0..120)
+            .map(|i| c(100.0 + (f64::from(i) * 0.25).sin() * 15.0))
+            .collect();
+        let batch = Nrtr::new(3.0).unwrap().batch(&candles);
+        let mut b = Nrtr::new(3.0).unwrap();
+        let streamed: Vec<_> = candles.iter().map(|c| b.update(*c)).collect();
+        assert_eq!(batch, streamed);
+    }
+}
@@ -0,0 +1,242 @@
+//! Order Flow Imbalance (OFI) from best-level order-book changes.
+
+use std::collections::VecDeque;
+
+use crate::microstructure::OrderBook;
+use crate::traits::Indicator;
+use crate::{Error, Result};
+
+/// Order Flow Imbalance — the rolling sum of best-level order-flow events over
+/// the last `period` order-book snapshots.
+///
+/// Following Cont, Kukanov & Stoikov (2014), each new snapshot contributes a
+/// signed event from how the best bid and ask moved versus the previous one:
+///
+/// ```text
+/// Δᵇ = qᵇₙ·1{Pᵇₙ ≥ Pᵇₙ₋₁} − qᵇₙ₋₁·1{Pᵇₙ ≤ Pᵇₙ₋₁}     (bid pressure)
+/// Δᵃ = qᵃₙ·1{Pᵃₙ ≤ Pᵃₙ₋₁} − qᵃₙ₋₁·1{Pᵃₙ ≥ Pᵃₙ₋₁}     (ask pressure)
+/// eₙ = Δᵇ − Δᵃ
+/// OFI = Σ eₙ  over the last `period` snapshots
+/// ```
+///
+/// A rising bid (or replenished bid size) and a falling/depleting ask both add
+/// positive flow; the mirror subtracts. The rolling sum is a strong
+/// short-horizon predictor of price moves: a large positive `OFI` reflects net
+/// buying pressure at the top of book, a large negative `OFI` net selling.
+///
+/// `Input = OrderBook`. Each `update` is O(1) (only the best levels are read).
+/// The first snapshot only seeds the reference quotes and emits `None`.
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Indicator, Level, OrderBook, OrderFlowImbalance};
+///
+/// let mut ofi = OrderFlowImbalance::new(20).unwrap();
+/// let book = OrderBook::new(
+///     vec![Level::new(100.0, 5.0).unwrap()],
+///     vec![Level::new(101.0, 4.0).unwrap()],
+/// )
+/// .unwrap();
+/// assert_eq!(ofi.update(book), None); // first snapshot seeds the reference
+/// ```
+#[derive(Debug, Clone)]
+pub struct OrderFlowImbalance {
+    period: usize,
+    prev: Option<(f64, f64, f64, f64)>, // (bid_px, bid_sz, ask_px, ask_sz)
+    window: VecDeque<f64>,
+    sum: f64,
+}
+
+impl OrderFlowImbalance {
+    /// Construct a new Order Flow Imbalance over the given snapshot window.
+    ///
+    /// # Errors
+    /// Returns [`Error::PeriodZero`] if `period == 0`.
+    pub fn new(period: usize) -> Result<Self> {
+        if period == 0 {
+            return Err(Error::PeriodZero);
+        }
+        Ok(Self {
+            period,
+            prev: None,
+            window: VecDeque::with_capacity(period),
+            sum: 0.0,
+        })
+    }
+
+    /// Configured period.
+    pub const fn period(&self) -> usize {
+        self.period
+    }
+}
+
+impl Indicator for OrderFlowImbalance {
+    type Input = OrderBook;
+    type Output = f64;
+
+    fn update(&mut self, book: OrderBook) -> Option<f64> {
+        // A book with no levels on a side carries no best-level information.
+        let (Some(bid), Some(ask)) = (book.best_bid(), book.best_ask()) else {
+            return None;
+        };
+        let curr = (bid.price, bid.size, ask.price, ask.size);
+        let Some((pb_px, pb_sz, pa_px, pa_sz)) = self.prev else {
+            self.prev = Some(curr);
+            return None;
+        };
+        self.prev = Some(curr);
+        let (bid_px, bid_sz, ask_px, ask_sz) = curr;
+        // Bid pressure: size added when the bid does not retreat, minus size
+        // removed when the bid does not advance.
+        let delta_b = f64::from(u8::from(bid_px >= pb_px)) * bid_sz
+            - f64::from(u8::from(bid_px <= pb_px)) * pb_sz;
+        // Ask pressure: size added when the ask does not advance, minus size
+        // removed when the ask does not retreat.
+        let delta_a = f64::from(u8::from(ask_px <= pa_px)) * ask_sz
+            - f64::from(u8::from(ask_px >= pa_px)) * pa_sz;
+        let event = delta_b - delta_a;
+        if self.window.len() == self.period {
+            let old = self.window.pop_front().expect("window is non-empty");
+            self.sum -= old;
+        }
+        self.window.push_back(event);
+        self.sum += event;
+        if self.window.len() < self.period {
+            return None;
+        }
+        Some(self.sum)
+    }
+
+    fn reset(&mut self) {
+        self.prev = None;
+        self.window.clear();
+        self.sum = 0.0;
+    }
+
+    fn warmup_period(&self) -> usize {
+        // One snapshot seeds the reference quotes, then `period` events fill the
+        // window.
+        self.period + 1
+    }
+
+    fn is_ready(&self) -> bool {
+        self.window.len() == self.period
+    }
+
+    fn name(&self) -> &'static str {
+        "OrderFlowImbalance"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::microstructure::Level;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    fn book(bid_px: f64, bid_sz: f64, ask_px: f64, ask_sz: f64) -> OrderBook {
+        OrderBook::new(
+            vec![Level::new(bid_px, bid_sz).unwrap()],
+            vec![Level::new(ask_px, ask_sz).unwrap()],
+        )
+        .unwrap()
+    }
+
+    #[test]
+    fn rejects_zero_period() {
+        assert!(matches!(OrderFlowImbalance::new(0), Err(Error::PeriodZero)));
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let ofi = OrderFlowImbalance::new(20).unwrap();
+        assert_eq!(ofi.period(), 20);
+        assert_eq!(ofi.warmup_period(), 21);
+        assert_eq!(ofi.name(), "OrderFlowImbalance");
+        assert!(!ofi.is_ready());
+    }
+
+    #[test]
+    fn first_snapshot_is_none() {
+        let mut ofi = OrderFlowImbalance::new(2).unwrap();
+        assert_eq!(ofi.update(book(100.0, 5.0, 101.0, 4.0)), None);
+    }
+
+    #[test]
+    fn empty_book_side_is_none() {
+        // A book with no levels on a side (only constructible via
+        // `new_unchecked`, since `OrderBook::new` rejects empty sides) carries
+        // no best-level information and emits `None` without advancing state.
+        let mut ofi = OrderFlowImbalance::new(2).unwrap();
+        let empty = OrderBook::new_unchecked(vec![], vec![]);
+        assert_eq!(ofi.update(empty), None);
+        // A real book afterwards still seeds the reference (state untouched).
+        assert_eq!(ofi.update(book(100.0, 5.0, 101.0, 4.0)), None);
+    }
+
+    #[test]
+    fn rising_bid_adds_positive_flow() {
+        // period 1. Reference book, then the bid lifts (price up) with size 6:
+        // Δᵇ = 6 (bid_px > prev), Δᵃ = (ask unchanged px=) ask_sz - ask_sz = 0
+        // when ask is identical => e = 6.
+        let mut ofi = OrderFlowImbalance::new(1).unwrap();
+        ofi.update(book(100.0, 5.0, 101.0, 4.0));
+        let out = ofi.update(book(100.5, 6.0, 101.0, 4.0)).unwrap();
+        assert_relative_eq!(out, 6.0, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn falling_bid_adds_negative_flow() {
+        // The bid drops in price: Δᵇ = −prev_bid_sz (bid_px < prev) = −5,
+        // ask identical => Δᵃ = 0 => e = −5.
+        let mut ofi = OrderFlowImbalance::new(1).unwrap();
+        ofi.update(book(100.0, 5.0, 101.0, 4.0));
+        let out = ofi.update(book(99.5, 3.0, 101.0, 4.0)).unwrap();
+        assert_relative_eq!(out, -5.0, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn rolling_sum_accumulates() {
+        let mut ofi = OrderFlowImbalance::new(2).unwrap();
+        ofi.update(book(100.0, 5.0, 101.0, 4.0));
+        let a = ofi.update(book(100.5, 6.0, 101.0, 4.0)); // warming (1 event)
+        assert!(a.is_none());
+        let b = ofi.update(book(101.0, 2.0, 101.5, 4.0)).unwrap(); // 2 events
+                                                                   // Second event: bid_px 101 > 100.5 => Δᵇ = 2; ask_px 101.5 > 101 =>
+                                                                   // Δᵃ = −prev_ask_sz = −4 => e2 = 2 − (−4) = 6. Sum = 6 + 6 = 12.
+        assert_relative_eq!(b, 12.0, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut ofi = OrderFlowImbalance::new(2).unwrap();
+        ofi.update(book(100.0, 5.0, 101.0, 4.0));
+        ofi.update(book(100.5, 6.0, 101.0, 4.0));
+        ofi.update(book(101.0, 2.0, 101.5, 4.0));
+        assert!(ofi.is_ready());
+        ofi.reset();
+        assert!(!ofi.is_ready());
+        assert_eq!(ofi.update(book(100.0, 5.0, 101.0, 4.0)), None);
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let books: Vec<OrderBook> = (0..30)
+            .map(|i| {
+                let f = f64::from(i);
+                book(
+                    100.0 + (f * 0.3).sin(),
+                    5.0 + (f * 0.5).cos().abs(),
+                    101.0 + (f * 0.3).sin(),
+                    4.0 + (f * 0.4).sin().abs(),
+                )
+            })
+            .collect();
+        let batch = OrderFlowImbalance::new(10).unwrap().batch(&books);
+        let mut b = OrderFlowImbalance::new(10).unwrap();
+        let streamed: Vec<_> = books.iter().map(|x| b.update(x.clone())).collect();
+        assert_eq!(batch, streamed);
+    }
+}
@@ -0,0 +1,293 @@
+//! Pivot Reversal — a breakout signal off the most recent confirmed swing pivots.
+
+use std::collections::VecDeque;
+
+use crate::error::{Error, Result};
+use crate::ohlcv::Candle;
+use crate::traits::Indicator;
+
+/// Pivot Reversal — emits a reversal **breakout signal** when price closes through
+/// the most recently confirmed swing pivot.
+///
+/// ```text
+/// pivot high: a bar whose high is strictly above the `left` bars before and the
+///             `right` bars after it (confirmed `right` bars late)
+/// pivot low : the mirror on lows
+/// signal = +1 when close crosses above the last confirmed pivot high
+/// signal = −1 when close crosses below the last confirmed pivot low
+/// signal =  0 otherwise
+/// ```
+///
+/// Unlike [`WilliamsFractals`](crate::WilliamsFractals), which merely *marks* the
+/// swing points, Pivot Reversal turns them into an actionable entry: once a swing
+/// high is confirmed it becomes a breakout trigger — a close back above it signals
+/// a bullish reversal — and likewise a close below a confirmed swing low signals a
+/// bearish reversal. This is the logic of the classic "Pivot Reversal" strategy.
+/// Signals fire only on the **crossing** bar, not while price sits beyond the
+/// level.
+///
+/// The first signal can appear once `left + right + 1` bars exist (a pivot needs
+/// neighbours on both sides). The output is `+1` / `0` / `−1`. Each `update` is
+/// O(`left + right`).
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Candle, Indicator, PivotReversal};
+///
+/// let mut indicator = PivotReversal::new(2, 2).unwrap();
+/// let mut fired = false;
+/// for i in 0..60 {
+///     let base = 100.0 + (f64::from(i) * 0.4).sin() * 5.0;
+///     let c = Candle::new(base, base + 1.0, base - 1.0, base, 1_000.0, 0).unwrap();
+///     match indicator.update(c) {
+///         Some(s) if s != 0.0 => fired = true,
+///         _ => {}
+///     }
+/// }
+/// let _ = fired;
+/// ```
+#[derive(Debug, Clone)]
+pub struct PivotReversal {
+    left: usize,
+    right: usize,
+    window: VecDeque<Candle>,
+    pivot_high: Option<f64>,
+    pivot_low: Option<f64>,
+    prev_close: Option<f64>,
+    last: Option<f64>,
+}
+
+impl PivotReversal {
+    /// Construct a Pivot Reversal with `left` bars before and `right` bars after
+    /// the pivot.
+    ///
+    /// # Errors
+    ///
+    /// Returns [`Error::PeriodZero`] if `left` or `right` is `0`.
+    pub fn new(left: usize, right: usize) -> Result<Self> {
+        if left == 0 || right == 0 {
+            return Err(Error::PeriodZero);
+        }
+        Ok(Self {
+            left,
+            right,
+            window: VecDeque::with_capacity(left + right + 1),
+            pivot_high: None,
+            pivot_low: None,
+            prev_close: None,
+            last: None,
+        })
+    }
+
+    /// Configured `(left, right)` strengths.
+    pub const fn params(&self) -> (usize, usize) {
+        (self.left, self.right)
+    }
+
+    /// Most recent confirmed pivot-high level, if any.
+    pub const fn pivot_high(&self) -> Option<f64> {
+        self.pivot_high
+    }
+
+    /// Most recent confirmed pivot-low level, if any.
+    pub const fn pivot_low(&self) -> Option<f64> {
+        self.pivot_low
+    }
+
+    /// Current value if available.
+    pub const fn value(&self) -> Option<f64> {
+        self.last
+    }
+}
+
+impl Indicator for PivotReversal {
+    type Input = Candle;
+    type Output = f64;
+
+    fn update(&mut self, candle: Candle) -> Option<f64> {
+        let close = candle.close;
+        if self.window.len() == self.left + self.right + 1 {
+            self.window.pop_front();
+        }
+        self.window.push_back(candle);
+        if self.window.len() < self.left + self.right + 1 {
+            self.prev_close = Some(close);
+            return None;
+        }
+
+        // Confirm the pivot candidate sitting `right` bars back.
+        let cand = self.window[self.left];
+        let is_high = self
+            .window
+            .iter()
+            .enumerate()
+            .all(|(i, c)| i == self.left || c.high < cand.high);
+        let is_low = self
+            .window
+            .iter()
+            .enumerate()
+            .all(|(i, c)| i == self.left || c.low > cand.low);
+        if is_high {
+            self.pivot_high = Some(cand.high);
+        }
+        if is_low {
+            self.pivot_low = Some(cand.low);
+        }
+
+        // Breakout crossing of the latest confirmed pivots by the current close.
+        let mut signal = 0.0;
+        if let (Some(ph), Some(prev)) = (self.pivot_high, self.prev_close) {
+            if close > ph && prev <= ph {
+                signal = 1.0;
+            }
+        }
+        if let (Some(pl), Some(prev)) = (self.pivot_low, self.prev_close) {
+            if close < pl && prev >= pl {
+                signal = -1.0;
+            }
+        }
+        self.prev_close = Some(close);
+        self.last = Some(signal);
+        Some(signal)
+    }
+
+    fn reset(&mut self) {
+        self.window.clear();
+        self.pivot_high = None;
+        self.pivot_low = None;
+        self.prev_close = None;
+        self.last = None;
+    }
+
+    fn warmup_period(&self) -> usize {
+        self.left + self.right + 1
+    }
+
+    fn is_ready(&self) -> bool {
+        self.last.is_some()
+    }
+
+    fn name(&self) -> &'static str {
+        "PivotReversal"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+
+    fn c(high: f64, low: f64, close: f64) -> Candle {
+        Candle::new_unchecked(close, high, low, close, 1_000.0, 0)
+    }
+
+    #[test]
+    fn rejects_zero_params() {
+        assert!(matches!(PivotReversal::new(0, 2), Err(Error::PeriodZero)));
+        assert!(matches!(PivotReversal::new(2, 0), Err(Error::PeriodZero)));
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let p = PivotReversal::new(2, 2).unwrap();
+        assert_eq!(p.params(), (2, 2));
+        assert_eq!(p.warmup_period(), 5);
+        assert_eq!(p.name(), "PivotReversal");
+        assert!(!p.is_ready());
+        assert_eq!(p.value(), None);
+        assert_eq!(p.pivot_high(), None);
+        assert_eq!(p.pivot_low(), None);
+    }
+
+    #[test]
+    fn first_emission_at_warmup_period() {
+        let mut p = PivotReversal::new(1, 1).unwrap();
+        let out = p.batch(&[c(10.0, 9.0, 9.5), c(12.0, 11.0, 11.5), c(10.0, 9.0, 9.5)]);
+        assert!(out[0].is_none());
+        assert!(out[1].is_none());
+        assert!(out[2].is_some());
+    }
+
+    #[test]
+    fn confirms_pivot_high() {
+        // bar1 is a local high; once bar2 arrives it is confirmed.
+        let mut p = PivotReversal::new(1, 1).unwrap();
+        p.batch(&[c(10.0, 9.0, 9.5), c(12.0, 11.0, 11.5), c(10.0, 9.0, 9.5)]);
+        assert_eq!(p.pivot_high(), Some(12.0));
+    }
+
+    #[test]
+    fn confirms_pivot_low() {
+        let mut p = PivotReversal::new(1, 1).unwrap();
+        p.batch(&[c(12.0, 11.0, 11.5), c(10.0, 8.0, 8.5), c(12.0, 11.0, 11.5)]);
+        assert_eq!(p.pivot_low(), Some(8.0));
+    }
+
+    #[test]
+    fn breakout_above_pivot_high_signals_plus_one() {
+        let mut p = PivotReversal::new(1, 1).unwrap();
+        // Form a pivot high at 12, then a close above 12 crosses it.
+        let candles = [
+            c(10.0, 9.0, 9.5),   // index 0
+            c(12.0, 11.0, 11.5), // pivot-high candidate
+            c(10.0, 9.0, 9.5),   // confirms pivot high = 12
+            c(11.0, 9.0, 9.0),   // close 9.0 (below 12)
+            c(14.0, 12.5, 13.0), // close 13.0 > 12 and prev 9.0 <= 12 -> +1
+        ];
+        let out = p.batch(&candles);
+        assert_eq!(out.last().unwrap(), &Some(1.0));
+    }
+
+    #[test]
+    fn breakdown_below_pivot_low_signals_minus_one() {
+        let mut p = PivotReversal::new(1, 1).unwrap();
+        let candles = [
+            c(12.0, 11.0, 11.5),
+            c(10.0, 8.0, 8.5),   // pivot-low candidate
+            c(12.0, 11.0, 11.5), // confirms pivot low = 8
+            c(12.0, 9.0, 11.0),  // close 11 (above 8)
+            c(9.0, 6.0, 7.0),    // close 7 < 8 and prev 11 >= 8 -> -1
+        ];
+        let out = p.batch(&candles);
+        assert_eq!(out.last().unwrap(), &Some(-1.0));
+    }
+
+    #[test]
+    fn no_break_is_zero() {
+        let mut p = PivotReversal::new(1, 1).unwrap();
+        let candles = [
+            c(10.0, 9.0, 9.5),
+            c(12.0, 11.0, 11.5),
+            c(10.0, 9.0, 9.5),
+            c(10.5, 9.0, 9.8),
+        ];
+        let out = p.batch(&candles);
+        assert_eq!(out.last().unwrap(), &Some(0.0));
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut p = PivotReversal::new(1, 1).unwrap();
+        p.batch(&[c(10.0, 9.0, 9.5), c(12.0, 11.0, 11.5), c(10.0, 9.0, 9.5)]);
+        assert!(p.is_ready());
+        p.reset();
+        assert!(!p.is_ready());
+        assert_eq!(p.value(), None);
+        assert_eq!(p.pivot_high(), None);
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let candles: Vec<Candle> = (0..80)
+            .map(|i| {
+                let base = 100.0 + (f64::from(i) * 0.4).sin() * 6.0;
+                c(base + 1.0, base - 1.0, base)
+            })
+            .collect();
+        let batch = PivotReversal::new(2, 2).unwrap().batch(&candles);
+        let mut b = PivotReversal::new(2, 2).unwrap();
+        let streamed: Vec<_> = candles.iter().map(|x| b.update(*x)).collect();
+        assert_eq!(batch, streamed);
+    }
+}
@@ -0,0 +1,243 @@
+//! Polarized Fractal Efficiency (PFE).
+
+use std::collections::VecDeque;
+
+use crate::error::{Error, Result};
+use crate::indicators::ema::Ema;
+use crate::traits::Indicator;
+
+/// Polarized Fractal Efficiency: how efficiently price travelled over the last
+/// `period` bars, signed by direction and smoothed by an EMA.
+///
+/// ```text
+/// straight  = sqrt((C_t - C_{t-n})^2 + n^2)            (direct distance over n bars)
+/// path      = Σ_{i=1..n} sqrt((C_{t-i+1} - C_{t-i})^2 + 1)   (sum of single-bar steps)
+/// raw       = 100 * sign(C_t - C_{t-n}) * straight / path
+/// PFE       = EMA(raw, smoothing)
+/// ```
+///
+/// The ratio `straight / path` is the fractal efficiency: it is `1` when price
+/// moved in a perfectly straight line and falls toward `0` as the path becomes
+/// jagged. Polarizing it by the sign of the net move pushes the reading to
+/// `+100` for an efficient up-move and `-100` for an efficient down-move, with
+/// choppy markets oscillating near zero. Because each single-bar step and the
+/// `n`-bar diagonal both carry the bar count on the x-axis (`+1` and `+n^2`),
+/// the path length is always `>= n`, so the denominator can never be zero.
+///
+/// Reference: Hans Hannula, *Stocks & Commodities*, 1994.
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Indicator, PolarizedFractalEfficiency};
+///
+/// let mut indicator = PolarizedFractalEfficiency::new(10, 5).unwrap();
+/// let mut last = None;
+/// for i in 0..40 {
+///     last = indicator.update(100.0 + f64::from(i));
+/// }
+/// assert!(last.is_some());
+/// ```
+#[derive(Debug, Clone)]
+pub struct PolarizedFractalEfficiency {
+    period: usize,
+    smoothing: usize,
+    closes: VecDeque<f64>,
+    prev_close: Option<f64>,
+    segments: VecDeque<f64>,
+    segment_sum: f64,
+    ema: Ema,
+}
+
+impl PolarizedFractalEfficiency {
+    /// Construct a PFE with the fractal lookback `period` and the EMA
+    /// `smoothing` period.
+    ///
+    /// # Errors
+    ///
+    /// Returns [`Error::PeriodZero`] if `period == 0` or `smoothing == 0`.
+    pub fn new(period: usize, smoothing: usize) -> Result<Self> {
+        if period == 0 {
+            return Err(Error::PeriodZero);
+        }
+        Ok(Self {
+            period,
+            smoothing,
+            closes: VecDeque::with_capacity(period + 1),
+            prev_close: None,
+            segments: VecDeque::with_capacity(period),
+            segment_sum: 0.0,
+            ema: Ema::new(smoothing)?,
+        })
+    }
+
+    /// Configured `(period, smoothing)`.
+    pub const fn periods(&self) -> (usize, usize) {
+        (self.period, self.smoothing)
+    }
+}
+
+impl Indicator for PolarizedFractalEfficiency {
+    type Input = f64;
+    type Output = f64;
+
+    fn update(&mut self, close: f64) -> Option<f64> {
+        if let Some(prev) = self.prev_close {
+            let diff = close - prev;
+            let segment = diff.mul_add(diff, 1.0).sqrt();
+            self.segment_sum += segment;
+            self.segments.push_back(segment);
+            if self.segments.len() > self.period {
+                self.segment_sum -= self.segments.pop_front().unwrap_or(0.0);
+            }
+        }
+        self.prev_close = Some(close);
+
+        self.closes.push_back(close);
+        if self.closes.len() > self.period + 1 {
+            self.closes.pop_front();
+        }
+        if self.closes.len() <= self.period {
+            return None;
+        }
+
+        let oldest = *self.closes.front().unwrap_or(&close);
+        let net = close - oldest;
+        let direction = if net > 0.0 {
+            1.0
+        } else if net < 0.0 {
+            -1.0
+        } else {
+            0.0
+        };
+        let span = self.period as f64;
+        let straight = net.mul_add(net, span * span).sqrt();
+        let raw = 100.0 * direction * straight / self.segment_sum;
+        self.ema.update(raw)
+    }
+
+    fn reset(&mut self) {
+        self.closes.clear();
+        self.prev_close = None;
+        self.segments.clear();
+        self.segment_sum = 0.0;
+        self.ema.reset();
+    }
+
+    fn warmup_period(&self) -> usize {
+        self.period + self.smoothing
+    }
+
+    fn is_ready(&self) -> bool {
+        self.ema.is_ready()
+    }
+
+    fn name(&self) -> &'static str {
+        "PolarizedFractalEfficiency"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    #[test]
+    fn rejects_zero_period() {
+        assert!(matches!(
+            PolarizedFractalEfficiency::new(0, 5),
+            Err(Error::PeriodZero)
+        ));
+        assert!(matches!(
+            PolarizedFractalEfficiency::new(10, 0),
+            Err(Error::PeriodZero)
+        ));
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let pfe = PolarizedFractalEfficiency::new(10, 5).unwrap();
+        assert_eq!(pfe.periods(), (10, 5));
+        assert_eq!(pfe.warmup_period(), 15);
+        assert_eq!(pfe.name(), "PolarizedFractalEfficiency");
+        assert!(!pfe.is_ready());
+    }
+
+    #[test]
+    fn warmup_emits_after_period_plus_smoothing() {
+        let mut pfe = PolarizedFractalEfficiency::new(4, 2).unwrap();
+        // raw needs period+1 = 5 closes; EMA(2) needs 2 raws -> first value at
+        // input 6 (index 5).
+        let inputs: Vec<f64> = (0..10).map(f64::from).collect();
+        let out = pfe.batch(&inputs);
+        assert!(out[4].is_none());
+        assert!(out[5].is_some());
+    }
+
+    #[test]
+    fn perfect_uptrend_is_strongly_positive() {
+        // A straight ramp: every step is +1, the diagonal is maximally
+        // efficient, so PFE saturates near +100.
+        let mut pfe = PolarizedFractalEfficiency::new(5, 3).unwrap();
+        let inputs: Vec<f64> = (0..30).map(f64::from).collect();
+        let last = pfe.batch(&inputs).last().unwrap().unwrap();
+        assert!(last > 99.0, "pfe {last} should be near +100");
+    }
+
+    #[test]
+    fn perfect_downtrend_is_strongly_negative() {
+        let mut pfe = PolarizedFractalEfficiency::new(5, 3).unwrap();
+        let inputs: Vec<f64> = (0..30).map(|i| -f64::from(i)).collect();
+        let last = pfe.batch(&inputs).last().unwrap().unwrap();
+        assert!(last < -99.0, "pfe {last} should be near -100");
+    }
+
+    #[test]
+    fn flat_market_returns_zero() {
+        // No net move over the window -> direction 0 -> raw 0 -> PFE 0.
+        let mut pfe = PolarizedFractalEfficiency::new(5, 3).unwrap();
+        let inputs = [10.0; 20];
+        let last = pfe.batch(&inputs).last().unwrap().unwrap();
+        assert_relative_eq!(last, 0.0, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn choppy_market_is_inefficient() {
+        // A sawtooth whip: the net move is tiny relative to the jagged path, so
+        // efficiency stays well below the +-100 saturation of a clean trend.
+        let mut pfe = PolarizedFractalEfficiency::new(5, 3).unwrap();
+        let inputs: Vec<f64> = (0..40)
+            .map(|i| if i % 2 == 0 { 100.0 } else { 102.0 })
+            .collect();
+        let last = pfe.batch(&inputs).last().unwrap().unwrap();
+        assert!(
+            last.abs() < 60.0,
+            "choppy pfe {last} should be far from +-100"
+        );
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut pfe = PolarizedFractalEfficiency::new(5, 3).unwrap();
+        let inputs: Vec<f64> = (0..30).map(f64::from).collect();
+        pfe.batch(&inputs);
+        assert!(pfe.is_ready());
+        pfe.reset();
+        assert!(!pfe.is_ready());
+        assert_eq!(pfe.periods(), (5, 3));
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let inputs: Vec<f64> = (0..80)
+            .map(|i| 100.0 + (f64::from(i) * 0.3).sin() * 5.0)
+            .collect();
+        let mut a = PolarizedFractalEfficiency::new(10, 5).unwrap();
+        let mut b = PolarizedFractalEfficiency::new(10, 5).unwrap();
+        assert_eq!(
+            a.batch(&inputs),
+            inputs.iter().map(|x| b.update(*x)).collect::<Vec<_>>()
+        );
+    }
+}
@@ -0,0 +1,230 @@
+//! Percentage Price Oscillator Histogram.
+
+use crate::error::{Error, Result};
+use crate::indicators::ema::Ema;
+use crate::indicators::ppo::Ppo;
+use crate::traits::Indicator;
+
+/// PPO Histogram — the `ppo − signal` bar of the Percentage Price Oscillator.
+///
+/// ```text
+/// ppo       = 100 · (EMA_fast − EMA_slow) / EMA_slow
+/// signal    = EMA(ppo, signal_period)
+/// histogram = ppo − signal
+/// ```
+///
+/// [`Ppo`](crate::Ppo) itself only emits the percentage line; this indicator
+/// adds the classic 9-period signal EMA on top and reports the resulting
+/// zero-centered histogram. Because PPO is scale-free (the EMA gap is divided
+/// by the slow EMA), the histogram is **comparable across instruments** — a
+/// PPO histogram of `0.4` means the same relative momentum on any asset, unlike
+/// the price-unit [`MacdHistogram`](crate::MacdHistogram).
+///
+/// With Appel's defaults `fast = 12`, `slow = 26`, `signal = 9`, the first
+/// value lands after `slow + signal − 1` inputs — the point at which the slow
+/// EMA and then the signal EMA are both seeded.
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Indicator, PpoHistogram};
+///
+/// let mut indicator = PpoHistogram::new(12, 26, 9).unwrap();
+/// let mut last = None;
+/// for i in 0..80 {
+///     last = indicator.update(100.0 + f64::from(i));
+/// }
+/// assert!(last.is_some());
+/// ```
+#[derive(Debug, Clone)]
+pub struct PpoHistogram {
+    ppo: Ppo,
+    signal_ema: Ema,
+    signal_period: usize,
+    current: Option<f64>,
+}
+
+impl PpoHistogram {
+    /// Construct a PPO histogram with the `fast`/`slow` EMA periods and the
+    /// `signal` EMA period.
+    ///
+    /// # Errors
+    ///
+    /// Returns [`Error::PeriodZero`] if any period is `0`, or
+    /// [`Error::InvalidPeriod`] if `fast >= slow`.
+    pub fn new(fast: usize, slow: usize, signal: usize) -> Result<Self> {
+        if signal == 0 {
+            return Err(Error::PeriodZero);
+        }
+        Ok(Self {
+            ppo: Ppo::new(fast, slow)?,
+            signal_ema: Ema::new(signal)?,
+            signal_period: signal,
+            current: None,
+        })
+    }
+
+    /// Default `(12, 26, 9)` configuration.
+    pub fn classic() -> Self {
+        Self::new(12, 26, 9).expect("classic PPO periods are valid")
+    }
+
+    /// Configured periods as `(fast, slow, signal)`.
+    pub const fn periods(&self) -> (usize, usize, usize) {
+        let (fast, slow) = self.ppo.periods();
+        (fast, slow, self.signal_period)
+    }
+
+    /// Current value if available.
+    pub const fn value(&self) -> Option<f64> {
+        self.current
+    }
+}
+
+impl Indicator for PpoHistogram {
+    type Input = f64;
+    type Output = f64;
+
+    fn update(&mut self, input: f64) -> Option<f64> {
+        // Guard before touching either stage so a non-finite input never
+        // advances the signal EMA on a stale, re-fed PPO value.
+        if !input.is_finite() {
+            return self.current;
+        }
+        let ppo = self.ppo.update(input)?;
+        let signal = self.signal_ema.update(ppo)?;
+        let histogram = ppo - signal;
+        self.current = Some(histogram);
+        Some(histogram)
+    }
+
+    fn reset(&mut self) {
+        self.ppo.reset();
+        self.signal_ema.reset();
+        self.current = None;
+    }
+
+    fn warmup_period(&self) -> usize {
+        // Slow EMA seeds the PPO, then the signal EMA needs `signal − 1` more.
+        self.ppo.warmup_period() + self.signal_period - 1
+    }
+
+    fn is_ready(&self) -> bool {
+        self.current.is_some()
+    }
+
+    fn name(&self) -> &'static str {
+        "PpoHistogram"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    #[test]
+    fn rejects_invalid_periods() {
+        assert!(matches!(
+            PpoHistogram::new(0, 26, 9),
+            Err(Error::PeriodZero)
+        ));
+        assert!(matches!(
+            PpoHistogram::new(12, 0, 9),
+            Err(Error::PeriodZero)
+        ));
+        assert!(matches!(
+            PpoHistogram::new(12, 26, 0),
+            Err(Error::PeriodZero)
+        ));
+        assert!(matches!(
+            PpoHistogram::new(26, 12, 9),
+            Err(Error::InvalidPeriod { .. })
+        ));
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let osc = PpoHistogram::classic();
+        assert_eq!(osc.periods(), (12, 26, 9));
+        assert_eq!(osc.name(), "PpoHistogram");
+        assert_eq!(osc.warmup_period(), 26 + 9 - 1);
+        assert_eq!(osc.value(), None);
+        assert!(!osc.is_ready());
+    }
+
+    #[test]
+    fn equals_ppo_minus_signal_ema() {
+        // The histogram must equal PPO minus an EMA(signal) composed by hand.
+        let prices: Vec<f64> = (1..=120)
+            .map(|i| 100.0 + (f64::from(i) * 0.2).sin() * 6.0)
+            .collect();
+        let got = PpoHistogram::new(12, 26, 9).unwrap().batch(&prices);
+
+        let mut ppo = Ppo::new(12, 26).unwrap();
+        let mut sig = Ema::new(9).unwrap();
+        let mut expected = Vec::with_capacity(prices.len());
+        for p in &prices {
+            let out = ppo
+                .update(*p)
+                .and_then(|line| sig.update(line).map(|signal| line - signal));
+            expected.push(out);
+        }
+        assert_eq!(got, expected);
+    }
+
+    #[test]
+    fn warmup_emits_first_value_at_warmup_period() {
+        let mut osc = PpoHistogram::new(3, 6, 3).unwrap();
+        let warmup = osc.warmup_period();
+        assert_eq!(warmup, 6 + 3 - 1);
+        for i in 1..warmup {
+            assert!(osc.update(100.0 + i as f64).is_none());
+        }
+        assert!(osc.update(100.0 + warmup as f64).is_some());
+        assert!(osc.is_ready());
+    }
+
+    #[test]
+    fn constant_series_converges_to_zero() {
+        let mut osc = PpoHistogram::classic();
+        let out = osc.batch(&[100.0_f64; 200]);
+        let last = out.iter().rev().flatten().next().expect("emits a value");
+        assert_relative_eq!(*last, 0.0, epsilon = 1e-9);
+    }
+
+    #[test]
+    fn ignores_non_finite_input() {
+        let mut osc = PpoHistogram::new(3, 6, 3).unwrap();
+        let out = osc.batch(&(1..=40).map(f64::from).collect::<Vec<_>>());
+        let before = *out.last().unwrap();
+        assert!(before.is_some());
+        assert_eq!(osc.update(f64::NAN), before);
+        assert_eq!(osc.update(f64::INFINITY), before);
+        assert_eq!(osc.value(), before);
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let prices: Vec<f64> = (1..=100)
+            .map(|i| 100.0 + (f64::from(i) * 0.4).cos() * 10.0)
+            .collect();
+        let mut a = PpoHistogram::classic();
+        let mut b = PpoHistogram::classic();
+        assert_eq!(
+            a.batch(&prices),
+            prices.iter().map(|p| b.update(*p)).collect::<Vec<_>>()
+        );
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut osc = PpoHistogram::classic();
+        osc.batch(&(1..=80).map(f64::from).collect::<Vec<_>>());
+        assert!(osc.is_ready());
+        osc.reset();
+        assert!(!osc.is_ready());
+        assert_eq!(osc.update(1.0), None);
+    }
+}
@@ -0,0 +1,253 @@
+//! Projection Bands (Mel Widner) — a high/low linear-regression projection
+//! envelope.
+
+use std::collections::VecDeque;
+
+use crate::error::{Error, Result};
+use crate::ohlcv::Candle;
+use crate::traits::Indicator;
+
+/// Projection Bands output.
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub struct ProjectionBandsOutput {
+    /// Upper band: the maximum forward-projected high in the window.
+    pub upper: f64,
+    /// Middle line: the midpoint of the upper and lower bands.
+    pub middle: f64,
+    /// Lower band: the minimum forward-projected low in the window.
+    pub lower: f64,
+}
+
+/// Projection Bands: forward-projected high/low envelope.
+///
+/// Mel Widner ("Projection Bands and the Projection Oscillator", *Technical
+/// Analysis of Stocks & Commodities*, May 1995) fits a separate linear
+/// regression to the highs and to the lows over the last `period` bars, then
+/// slides every bar's high and low forward to the current bar along its own
+/// slope. The upper band is the maximum of the projected highs, the lower band
+/// the minimum of the projected lows:
+///
+/// ```text
+/// slope_h = OLS slope of (x, high) over the window
+/// slope_l = OLS slope of (x, low)  over the window
+/// // bar i (0 = oldest, period-1 = newest) is (period-1-i) bars in the past
+/// upper   = max over i of [ high_i + slope_h · (period-1-i) ]
+/// lower   = min over i of [ low_i  + slope_l · (period-1-i) ]
+/// middle  = (upper + lower) / 2
+/// ```
+///
+/// Unlike [`LinRegChannel`](crate::LinRegChannel) and
+/// [`StandardErrorBands`](crate::StandardErrorBands) — which wrap a single
+/// close-regression endpoint by a dispersion statistic — Projection Bands are
+/// built from the *extremes*: the envelope adapts to the trend's slope yet
+/// always contains every projected high and low, so by construction price never
+/// pierces the bands within the window. A flat slope reduces the bands to the
+/// rolling highest-high / lowest-low (a Donchian channel); a steep slope tilts
+/// the whole envelope with the trend.
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Candle, Indicator, ProjectionBands};
+///
+/// let mut indicator = ProjectionBands::new(14).unwrap();
+/// let mut last = None;
+/// for i in 0..30 {
+///     let base = 100.0 + f64::from(i);
+///     let candle =
+///         Candle::new(base, base + 2.0, base - 2.0, base + 1.0, 10.0, i64::from(i)).unwrap();
+///     last = indicator.update(candle);
+/// }
+/// assert!(last.is_some());
+/// ```
+#[derive(Debug, Clone)]
+pub struct ProjectionBands {
+    period: usize,
+    highs: VecDeque<f64>,
+    lows: VecDeque<f64>,
+    sum_x: f64,
+    sum_xx: f64,
+}
+
+impl ProjectionBands {
+    /// Construct new Projection Bands.
+    ///
+    /// # Errors
+    /// Returns [`Error::InvalidPeriod`] if `period < 2` (a regression slope
+    /// needs at least two points).
+    pub fn new(period: usize) -> Result<Self> {
+        if period < 2 {
+            return Err(Error::InvalidPeriod {
+                message: "projection bands need period >= 2",
+            });
+        }
+        let n = period as f64;
+        Ok(Self {
+            period,
+            highs: VecDeque::with_capacity(period),
+            lows: VecDeque::with_capacity(period),
+            sum_x: n * (n - 1.0) / 2.0,
+            sum_xx: (n - 1.0) * n * (2.0 * n - 1.0) / 6.0,
+        })
+    }
+
+    /// Configured period.
+    pub const fn period(&self) -> usize {
+        self.period
+    }
+
+    /// OLS slope of `(0..period, values)` over the live window.
+    fn slope(&self, values: &VecDeque<f64>) -> f64 {
+        let n = self.period as f64;
+        let mut sum_y = 0.0;
+        let mut sum_xy = 0.0;
+        for (i, &y) in values.iter().enumerate() {
+            sum_y += y;
+            sum_xy += (i as f64) * y;
+        }
+        let denom = n * self.sum_xx - self.sum_x * self.sum_x;
+        (n * sum_xy - self.sum_x * sum_y) / denom
+    }
+}
+
+impl Indicator for ProjectionBands {
+    type Input = Candle;
+    type Output = ProjectionBandsOutput;
+
+    fn update(&mut self, candle: Candle) -> Option<ProjectionBandsOutput> {
+        if self.highs.len() == self.period {
+            self.highs.pop_front();
+            self.lows.pop_front();
+        }
+        self.highs.push_back(candle.high);
+        self.lows.push_back(candle.low);
+        if self.highs.len() < self.period {
+            return None;
+        }
+
+        let slope_h = self.slope(&self.highs);
+        let slope_l = self.slope(&self.lows);
+        let last = (self.period - 1) as f64;
+
+        let mut upper = f64::NEG_INFINITY;
+        let mut lower = f64::INFINITY;
+        for (i, (&high, &low)) in self.highs.iter().zip(self.lows.iter()).enumerate() {
+            let forward = last - (i as f64);
+            let projected_high = high + slope_h * forward;
+            let projected_low = low + slope_l * forward;
+            if projected_high > upper {
+                upper = projected_high;
+            }
+            if projected_low < lower {
+                lower = projected_low;
+            }
+        }
+
+        Some(ProjectionBandsOutput {
+            upper,
+            middle: f64::midpoint(upper, lower),
+            lower,
+        })
+    }
+
+    fn reset(&mut self) {
+        self.highs.clear();
+        self.lows.clear();
+    }
+
+    fn warmup_period(&self) -> usize {
+        self.period
+    }
+
+    fn is_ready(&self) -> bool {
+        self.highs.len() == self.period
+    }
+
+    fn name(&self) -> &'static str {
+        "ProjectionBands"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use approx::assert_relative_eq;
+
+    fn candle(high: f64, low: f64, close: f64, ts: i64) -> Candle {
+        Candle::new(low, high, low, close, 10.0, ts).unwrap()
+    }
+
+    #[test]
+    fn rejects_period_below_two() {
+        assert!(matches!(
+            ProjectionBands::new(0),
+            Err(Error::InvalidPeriod { .. })
+        ));
+        assert!(matches!(
+            ProjectionBands::new(1),
+            Err(Error::InvalidPeriod { .. })
+        ));
+        assert!(ProjectionBands::new(2).is_ok());
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let pb = ProjectionBands::new(14).unwrap();
+        assert_eq!(pb.period(), 14);
+        assert_eq!(pb.warmup_period(), 14);
+        assert_eq!(pb.name(), "ProjectionBands");
+        assert!(!pb.is_ready());
+    }
+
+    #[test]
+    fn warms_up_then_emits() {
+        let mut pb = ProjectionBands::new(3).unwrap();
+        assert!(pb.update(candle(10.0, 8.0, 9.0, 0)).is_none());
+        assert!(pb.update(candle(12.0, 9.0, 11.0, 1)).is_none());
+        assert!(pb.update(candle(11.0, 10.0, 11.0, 2)).is_some());
+        assert!(pb.is_ready());
+    }
+
+    #[test]
+    fn known_projection() {
+        // highs 10,12,11 -> slope_h = 0.5; projected = 11, 12.5, 11 -> upper 12.5
+        // lows   8, 9,10 -> slope_l = 1.0; projected = 10, 10,  10 -> lower 10
+        let mut pb = ProjectionBands::new(3).unwrap();
+        pb.update(candle(10.0, 8.0, 9.0, 0));
+        pb.update(candle(12.0, 9.0, 11.0, 1));
+        let out = pb.update(candle(11.0, 10.0, 11.0, 2)).unwrap();
+        assert_relative_eq!(out.upper, 12.5, epsilon = 1e-9);
+        assert_relative_eq!(out.lower, 10.0, epsilon = 1e-9);
+        assert_relative_eq!(out.middle, 11.25, epsilon = 1e-9);
+    }
+
+    #[test]
+    fn perfect_trend_pins_bands_to_current_extremes() {
+        // High_i and Low_i both rise by exactly 1 per bar: every projected high
+        // collapses onto the current high, every projected low onto the current
+        // low.
+        let mut pb = ProjectionBands::new(5).unwrap();
+        let mut last = None;
+        for i in 0..10 {
+            let high = 100.0 + f64::from(i);
+            let low = 95.0 + f64::from(i);
+            last = pb.update(candle(high, low, high, i64::from(i)));
+        }
+        let out = last.unwrap();
+        assert_relative_eq!(out.upper, 109.0, epsilon = 1e-9);
+        assert_relative_eq!(out.lower, 104.0, epsilon = 1e-9);
+        assert_relative_eq!(out.middle, 106.5, epsilon = 1e-9);
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut pb = ProjectionBands::new(3).unwrap();
+        pb.update(candle(10.0, 8.0, 9.0, 0));
+        pb.update(candle(12.0, 9.0, 11.0, 1));
+        pb.update(candle(11.0, 10.0, 11.0, 2));
+        assert!(pb.is_ready());
+        pb.reset();
+        assert!(!pb.is_ready());
+        assert!(pb.update(candle(10.0, 8.0, 9.0, 3)).is_none());
+    }
+}
@@ -0,0 +1,168 @@
+//! Projection Oscillator (Mel Widner) — the close's position inside the
+//! [`ProjectionBands`](crate::ProjectionBands).
+
+use crate::error::Result;
+use crate::indicators::projection_bands::ProjectionBands;
+use crate::ohlcv::Candle;
+use crate::traits::Indicator;
+
+/// Projection Oscillator: where the close sits inside the projection bands,
+/// scaled to `0..100`.
+///
+/// The companion to [`ProjectionBands`](crate::ProjectionBands) from Mel
+/// Widner's May 1995 *Stocks & Commodities* article. It maps the close onto the
+/// `[lower, upper]` projection envelope:
+///
+/// ```text
+/// PO = 100 · (close − lower) / (upper − lower)
+/// ```
+///
+/// `PO = 0` means the close is sitting on the lower band, `PO = 100` on the
+/// upper band, and `PO = 50` at the midline. Because the bands by construction
+/// bracket every projected high and low, the close almost always falls inside
+/// them and the oscillator stays in `0..100` — readings near the extremes flag
+/// an overbought/oversold position *relative to the trend-tilted channel*
+/// rather than to a horizontal level. When the bands collapse (a zero-range
+/// window, `upper == lower`) the position is undefined and the oscillator
+/// returns the neutral `50.0`.
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Candle, Indicator, ProjectionOscillator};
+///
+/// let mut indicator = ProjectionOscillator::new(14).unwrap();
+/// let mut last = None;
+/// for i in 0..30 {
+///     let base = 100.0 + f64::from(i);
+///     let candle =
+///         Candle::new(base, base + 2.0, base - 2.0, base + 1.0, 10.0, i64::from(i)).unwrap();
+///     last = indicator.update(candle);
+/// }
+/// assert!(last.is_some());
+/// ```
+#[derive(Debug, Clone)]
+pub struct ProjectionOscillator {
+    bands: ProjectionBands,
+}
+
+impl ProjectionOscillator {
+    /// Construct a new Projection Oscillator.
+    ///
+    /// # Errors
+    /// Returns [`Error::InvalidPeriod`](crate::Error::InvalidPeriod) if
+    /// `period < 2`.
+    pub fn new(period: usize) -> Result<Self> {
+        Ok(Self {
+            bands: ProjectionBands::new(period)?,
+        })
+    }
+
+    /// Configured period.
+    pub const fn period(&self) -> usize {
+        self.bands.period()
+    }
+}
+
+impl Indicator for ProjectionOscillator {
+    type Input = Candle;
+    type Output = f64;
+
+    fn update(&mut self, candle: Candle) -> Option<f64> {
+        let bands = self.bands.update(candle)?;
+        let width = bands.upper - bands.lower;
+        if width == 0.0 {
+            return Some(50.0);
+        }
+        Some(100.0 * (candle.close - bands.lower) / width)
+    }
+
+    fn reset(&mut self) {
+        self.bands.reset();
+    }
+
+    fn warmup_period(&self) -> usize {
+        self.bands.warmup_period()
+    }
+
+    fn is_ready(&self) -> bool {
+        self.bands.is_ready()
+    }
+
+    fn name(&self) -> &'static str {
+        "ProjectionOscillator"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::error::Error;
+    use approx::assert_relative_eq;
+
+    fn candle(high: f64, low: f64, close: f64, ts: i64) -> Candle {
+        Candle::new(low, high, low, close, 10.0, ts).unwrap()
+    }
+
+    #[test]
+    fn rejects_period_below_two() {
+        assert!(matches!(
+            ProjectionOscillator::new(1),
+            Err(Error::InvalidPeriod { .. })
+        ));
+        assert!(ProjectionOscillator::new(2).is_ok());
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let po = ProjectionOscillator::new(14).unwrap();
+        assert_eq!(po.period(), 14);
+        assert_eq!(po.warmup_period(), 14);
+        assert_eq!(po.name(), "ProjectionOscillator");
+        assert!(!po.is_ready());
+    }
+
+    #[test]
+    fn warms_up_then_emits() {
+        let mut po = ProjectionOscillator::new(3).unwrap();
+        assert!(po.update(candle(10.0, 8.0, 9.0, 0)).is_none());
+        assert!(po.update(candle(12.0, 9.0, 11.0, 1)).is_none());
+        assert!(po.update(candle(11.0, 10.0, 11.0, 2)).is_some());
+        assert!(po.is_ready());
+    }
+
+    #[test]
+    fn known_position() {
+        // Same window as ProjectionBands::known_projection: upper 12.5, lower 10.
+        // close 11 -> 100 * (11 - 10) / (12.5 - 10) = 40.
+        let mut po = ProjectionOscillator::new(3).unwrap();
+        po.update(candle(10.0, 8.0, 9.0, 0));
+        po.update(candle(12.0, 9.0, 11.0, 1));
+        let out = po.update(candle(11.0, 10.0, 11.0, 2)).unwrap();
+        assert_relative_eq!(out, 40.0, epsilon = 1e-9);
+    }
+
+    #[test]
+    fn collapsed_bands_return_neutral() {
+        // Zero-range, perfectly trending candles: upper == lower every bar.
+        let mut po = ProjectionOscillator::new(3).unwrap();
+        let mut last = None;
+        for i in 0..6 {
+            let v = 100.0 + f64::from(i);
+            last = po.update(candle(v, v, v, i64::from(i)));
+        }
+        assert_relative_eq!(last.unwrap(), 50.0, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut po = ProjectionOscillator::new(3).unwrap();
+        po.update(candle(10.0, 8.0, 9.0, 0));
+        po.update(candle(12.0, 9.0, 11.0, 1));
+        po.update(candle(11.0, 10.0, 11.0, 2));
+        assert!(po.is_ready());
+        po.reset();
+        assert!(!po.is_ready());
+        assert!(po.update(candle(10.0, 8.0, 9.0, 3)).is_none());
+    }
+}
@@ -0,0 +1,358 @@
+//! QQE — Quantitative Qualitative Estimation.
+
+use crate::error::{Error, Result};
+use crate::indicators::ema::Ema;
+use crate::indicators::rsi::Rsi;
+use crate::traits::Indicator;
+
+/// One QQE reading: the smoothed RSI and its volatility-trailing line.
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub struct QqeOutput {
+    /// The EMA-smoothed RSI (the fast QQE line).
+    pub rsi_ma: f64,
+    /// The trailing line (the slow QQE line): an ATR-of-RSI trailing stop that
+    /// the smoothed RSI rides above in an uptrend and below in a downtrend.
+    pub trailing_line: f64,
+}
+
+/// QQE — Quantitative Qualitative Estimation (Igor Livshin).
+///
+/// QQE smooths the RSI, then builds an "ATR of the RSI" trailing stop around it.
+/// Crossovers of the smoothed RSI and that trailing line give cleaner momentum
+/// signals than the raw RSI:
+///
+/// ```text
+/// rsi_ma   = EMA(RSI(price, rsi_period), smoothing)
+/// atr_rsi  = |rsi_ma − rsi_ma_prev|
+/// ma_atr   = EMA(atr_rsi, 2·rsi_period − 1)        // Wilder length
+/// dar      = EMA(ma_atr, 2·rsi_period − 1) · factor // smoothed band width
+///
+/// long_band  = (rsi_ma_prev > long_band_prev  && rsi_ma > long_band_prev)
+///              ? max(long_band_prev,  rsi_ma − dar) : rsi_ma − dar
+/// short_band = (rsi_ma_prev < short_band_prev && rsi_ma < short_band_prev)
+///              ? min(short_band_prev, rsi_ma + dar) : rsi_ma + dar
+/// trend      = cross-up of short_band → +1, cross-down of long_band → −1, else hold
+/// trailing   = trend == +1 ? long_band : short_band
+/// ```
+///
+/// The trailing line ratchets in the trend direction (only ever tightening until
+/// the smoothed RSI crosses it), exactly like a [`SuperTrend`](crate::SuperTrend)
+/// on the RSI. Livshin's defaults are `rsi_period = 14`, `smoothing = 5`,
+/// `factor = 4.236`.
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Indicator, Qqe};
+///
+/// let mut qqe = Qqe::new(14, 5, 4.236).unwrap();
+/// let mut last = None;
+/// for i in 0..200 {
+///     last = qqe.update(100.0 + (f64::from(i) * 0.1).sin() * 8.0);
+/// }
+/// assert!(last.is_some());
+/// ```
+#[derive(Debug, Clone)]
+pub struct Qqe {
+    rsi: Rsi,
+    rsi_ma: Ema,
+    ma_atr: Ema,
+    dar_ema: Ema,
+    factor: f64,
+    prev_rsi_ma: Option<f64>,
+    bands: Option<(f64, f64, i8)>, // (long_band, short_band, trend)
+    last_value: Option<QqeOutput>,
+}
+
+impl Qqe {
+    /// Construct a QQE with the RSI period, RSI smoothing, and band `factor`.
+    ///
+    /// # Errors
+    ///
+    /// Returns [`Error::PeriodZero`] if `rsi_period` or `smoothing` is `0`, or
+    /// [`Error::InvalidPeriod`] if `factor` is non-finite or not positive.
+    pub fn new(rsi_period: usize, smoothing: usize, factor: f64) -> Result<Self> {
+        if rsi_period == 0 || smoothing == 0 {
+            return Err(Error::PeriodZero);
+        }
+        if !factor.is_finite() || factor <= 0.0 {
+            return Err(Error::InvalidPeriod {
+                message: "QQE factor must be a finite positive value",
+            });
+        }
+        let wilders = 2 * rsi_period - 1;
+        Ok(Self {
+            rsi: Rsi::new(rsi_period)?,
+            rsi_ma: Ema::new(smoothing)?,
+            ma_atr: Ema::new(wilders)?,
+            dar_ema: Ema::new(wilders)?,
+            factor,
+            prev_rsi_ma: None,
+            bands: None,
+            last_value: None,
+        })
+    }
+
+    /// Configured band factor.
+    pub const fn factor(&self) -> f64 {
+        self.factor
+    }
+
+    /// Current value if available.
+    pub const fn value(&self) -> Option<QqeOutput> {
+        self.last_value
+    }
+}
+
+impl Indicator for Qqe {
+    type Input = f64;
+    type Output = QqeOutput;
+
+    fn update(&mut self, price: f64) -> Option<QqeOutput> {
+        let rsi = self.rsi.update(price)?;
+        let rsi_ma = self.rsi_ma.update(rsi)?;
+
+        let Some(prev_ma) = self.prev_rsi_ma else {
+            self.prev_rsi_ma = Some(rsi_ma);
+            return None;
+        };
+        let atr_rsi = (rsi_ma - prev_ma).abs();
+        self.prev_rsi_ma = Some(rsi_ma);
+
+        let ma_atr = self.ma_atr.update(atr_rsi)?;
+        let dar = self.dar_ema.update(ma_atr)? * self.factor;
+
+        let new_long = rsi_ma - dar;
+        let new_short = rsi_ma + dar;
+
+        let (long_band, short_band, trend) = match self.bands {
+            Some((lb_prev, sb_prev, tr_prev)) => {
+                let lb = if prev_ma > lb_prev && rsi_ma > lb_prev {
+                    lb_prev.max(new_long)
+                } else {
+                    new_long
+                };
+                let sb = if prev_ma < sb_prev && rsi_ma < sb_prev {
+                    sb_prev.min(new_short)
+                } else {
+                    new_short
+                };
+                let tr = if prev_ma <= sb_prev && rsi_ma > sb_prev {
+                    1
+                } else if prev_ma >= lb_prev && rsi_ma < lb_prev {
+                    -1
+                } else {
+                    tr_prev
+                };
+                (lb, sb, tr)
+            }
+            None => (new_long, new_short, 1),
+        };
+        self.bands = Some((long_band, short_band, trend));
+
+        let trailing_line = if trend == 1 { long_band } else { short_band };
+        let out = QqeOutput {
+            rsi_ma,
+            trailing_line,
+        };
+        self.last_value = Some(out);
+        Some(out)
+    }
+
+    fn reset(&mut self) {
+        self.rsi.reset();
+        self.rsi_ma.reset();
+        self.ma_atr.reset();
+        self.dar_ema.reset();
+        self.prev_rsi_ma = None;
+        self.bands = None;
+        self.last_value = None;
+    }
+
+    fn warmup_period(&self) -> usize {
+        // RSI (rsi_period + 1) -> rsi_ma EMA -> one bar for the first atr_rsi ->
+        // ma_atr EMA -> dar EMA. Expressed via the component warmups so it stays
+        // correct if those change.
+        self.rsi.warmup_period()
+            + self.rsi_ma.warmup_period()
+            + self.ma_atr.warmup_period()
+            + self.dar_ema.warmup_period()
+            - 2
+    }
+
+    fn is_ready(&self) -> bool {
+        self.last_value.is_some()
+    }
+
+    fn name(&self) -> &'static str {
+        "QQE"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    /// Independent reference replaying the full QQE recurrence.
+    fn naive(
+        prices: &[f64],
+        rsi_period: usize,
+        smoothing: usize,
+        factor: f64,
+    ) -> Vec<Option<QqeOutput>> {
+        let mut rsi = Rsi::new(rsi_period).unwrap();
+        let mut rsi_ma = Ema::new(smoothing).unwrap();
+        let wilders = 2 * rsi_period - 1;
+        let mut ma_atr = Ema::new(wilders).unwrap();
+        let mut dar_ema = Ema::new(wilders).unwrap();
+        let mut prev_ma: Option<f64> = None;
+        let mut bands: Option<(f64, f64, i8)> = None;
+        let mut out = Vec::with_capacity(prices.len());
+        for &p in prices {
+            let v = (|| {
+                let r = rsi.update(p)?;
+                let m = rsi_ma.update(r)?;
+                let Some(pm) = prev_ma else {
+                    prev_ma = Some(m);
+                    return None;
+                };
+                let atr = (m - pm).abs();
+                prev_ma = Some(m);
+                let ma = ma_atr.update(atr)?;
+                let dar = dar_ema.update(ma)? * factor;
+                let nl = m - dar;
+                let ns = m + dar;
+                let (lb, sb, tr) = match bands {
+                    Some((lbp, sbp, trp)) => {
+                        let lb = if pm > lbp && m > lbp { lbp.max(nl) } else { nl };
+                        let sb = if pm < sbp && m < sbp { sbp.min(ns) } else { ns };
+                        let tr = if pm <= sbp && m > sbp {
+                            1
+                        } else if pm >= lbp && m < lbp {
+                            -1
+                        } else {
+                            trp
+                        };
+                        (lb, sb, tr)
+                    }
+                    None => (nl, ns, 1),
+                };
+                bands = Some((lb, sb, tr));
+                Some(QqeOutput {
+                    rsi_ma: m,
+                    trailing_line: if tr == 1 { lb } else { sb },
+                })
+            })();
+            out.push(v);
+        }
+        out
+    }
+
+    #[test]
+    fn rejects_bad_params() {
+        assert!(matches!(Qqe::new(0, 5, 4.236), Err(Error::PeriodZero)));
+        assert!(matches!(Qqe::new(14, 0, 4.236), Err(Error::PeriodZero)));
+        assert!(matches!(
+            Qqe::new(14, 5, 0.0),
+            Err(Error::InvalidPeriod { .. })
+        ));
+        assert!(matches!(
+            Qqe::new(14, 5, f64::NAN),
+            Err(Error::InvalidPeriod { .. })
+        ));
+    }
+
+    /// Cover the const accessors `factor` + `value` and the Indicator-impl
+    /// `name`. `warmup_period` is covered by `first_emission_matches_warmup`.
+    #[test]
+    fn accessors_and_metadata() {
+        let qqe = Qqe::new(14, 5, 4.236).unwrap();
+        assert_relative_eq!(qqe.factor(), 4.236, epsilon = 1e-12);
+        assert_eq!(qqe.value(), None);
+        assert_eq!(qqe.name(), "QQE");
+    }
+
+    #[test]
+    fn first_emission_matches_warmup() {
+        // A long trend-up-then-down series exercises both trend flips and the
+        // band tighten/reset branches.
+        let prices: Vec<f64> = (0..200)
+            .map(|i| 100.0 + (f64::from(i) * 0.06).sin() * 20.0)
+            .collect();
+        let mut qqe = Qqe::new(14, 5, 4.236).unwrap();
+        let out = qqe.batch(&prices);
+        let warmup = qqe.warmup_period();
+        for (i, v) in out.iter().enumerate().take(warmup - 1) {
+            assert!(v.is_none(), "index {i} must be None during warmup");
+        }
+        assert!(
+            out[warmup - 1].is_some(),
+            "first value at warmup_period - 1"
+        );
+    }
+
+    #[test]
+    fn matches_naive_over_full_cycle() {
+        // Up, range, and down phases so every band/trend branch is traversed.
+        let prices: Vec<f64> = (0..220)
+            .map(|i| {
+                let t = f64::from(i);
+                100.0 + (t * 0.05).sin() * 18.0 + (t * 0.2).cos() * 4.0
+            })
+            .collect();
+        let mut qqe = Qqe::new(14, 5, 4.236).unwrap();
+        let got = qqe.batch(&prices);
+        let want = naive(&prices, 14, 5, 4.236);
+        for (i, (g, w)) in got.iter().zip(want.iter()).enumerate() {
+            assert_eq!(g.is_some(), w.is_some(), "readiness mismatch at {i}");
+            if let (Some(a), Some(b)) = (g, w) {
+                assert_relative_eq!(a.rsi_ma, b.rsi_ma, epsilon = 1e-9);
+                assert_relative_eq!(a.trailing_line, b.trailing_line, epsilon = 1e-9);
+            }
+        }
+    }
+
+    #[test]
+    fn trailing_line_below_rsi_ma_in_uptrend() {
+        // Sustained rise: trend resolves to +1 and the trailing (long) band sits
+        // below the smoothed RSI.
+        let prices: Vec<f64> = (1..=120).map(f64::from).collect();
+        let mut qqe = Qqe::new(14, 5, 4.236).unwrap();
+        let last = qqe.batch(&prices).into_iter().flatten().last().unwrap();
+        assert!(
+            last.trailing_line <= last.rsi_ma,
+            "uptrend trailing {} should sit at/below rsi_ma {}",
+            last.trailing_line,
+            last.rsi_ma
+        );
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut qqe = Qqe::new(14, 5, 4.236).unwrap();
+        qqe.batch(
+            &(0..120)
+                .map(|i| 100.0 + (f64::from(i) * 0.1).sin() * 8.0)
+                .collect::<Vec<_>>(),
+        );
+        assert!(qqe.is_ready());
+        qqe.reset();
+        assert!(!qqe.is_ready());
+        assert_eq!(qqe.update(1.0), None);
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let prices: Vec<f64> = (0..150)
+            .map(|i| 50.0 + (f64::from(i) * 0.12).sin() * 12.0)
+            .collect();
+        let mut a = Qqe::new(14, 5, 4.236).unwrap();
+        let mut b = Qqe::new(14, 5, 4.236).unwrap();
+        assert_eq!(
+            a.batch(&prices),
+            prices.iter().map(|p| b.update(*p)).collect::<Vec<_>>()
+        );
+    }
+}
@@ -0,0 +1,168 @@
+//! Qstick — Tushar Chande's measure of buying vs. selling pressure.
+
+use crate::error::Result;
+use crate::indicators::sma::Sma;
+use crate::ohlcv::Candle;
+use crate::traits::Indicator;
+
+/// Qstick: the simple moving average of the body `close - open` over `period`
+/// bars.
+///
+/// Positive values indicate a run of bars that closed above their open (net
+/// buying pressure); negative values indicate net selling pressure. A zero
+/// crossing is read as a shift in short-term sentiment.
+///
+/// ```text
+/// Qstick = SMA(close - open, period)
+/// ```
+///
+/// Reference: Tushar Chande, *The New Technical Trader*, 1994.
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Candle, Indicator, Qstick};
+///
+/// let mut indicator = Qstick::new(5).unwrap();
+/// let mut last = None;
+/// for i in 0..20 {
+///     let base = 100.0 + f64::from(i);
+///     let candle =
+///         Candle::new(base, base + 2.0, base - 1.0, base + 1.0, 1.0, i64::from(i)).unwrap();
+///     last = indicator.update(candle);
+/// }
+/// assert!(last.is_some());
+/// ```
+#[derive(Debug, Clone)]
+pub struct Qstick {
+    period: usize,
+    sma: Sma,
+}
+
+impl Qstick {
+    /// Construct a Qstick with the given averaging period.
+    ///
+    /// # Errors
+    ///
+    /// Returns [`Error::PeriodZero`](crate::error::Error::PeriodZero) if `period == 0`.
+    pub fn new(period: usize) -> Result<Self> {
+        Ok(Self {
+            period,
+            sma: Sma::new(period)?,
+        })
+    }
+
+    /// Configured averaging period.
+    pub const fn period(&self) -> usize {
+        self.period
+    }
+}
+
+impl Indicator for Qstick {
+    type Input = Candle;
+    type Output = f64;
+
+    fn update(&mut self, candle: Candle) -> Option<f64> {
+        self.sma.update(candle.close - candle.open)
+    }
+
+    fn reset(&mut self) {
+        self.sma.reset();
+    }
+
+    fn warmup_period(&self) -> usize {
+        self.period
+    }
+
+    fn is_ready(&self) -> bool {
+        self.sma.is_ready()
+    }
+
+    fn name(&self) -> &'static str {
+        "Qstick"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::error::Error;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    fn candle(open: f64, close: f64, ts: i64) -> Candle {
+        let high = open.max(close) + 1.0;
+        let low = open.min(close) - 1.0;
+        Candle::new(open, high, low, close, 1.0, ts).unwrap()
+    }
+
+    #[test]
+    fn rejects_zero_period() {
+        assert!(matches!(Qstick::new(0), Err(Error::PeriodZero)));
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let q = Qstick::new(5).unwrap();
+        assert_eq!(q.period(), 5);
+        assert_eq!(q.warmup_period(), 5);
+        assert_eq!(q.name(), "Qstick");
+        assert!(!q.is_ready());
+    }
+
+    #[test]
+    fn warmup_emits_first_value_at_period() {
+        let mut q = Qstick::new(3).unwrap();
+        let candles: Vec<Candle> = (0..3).map(|i| candle(10.0, 11.0, i)).collect();
+        let out = q.batch(&candles);
+        assert!(out[0].is_none());
+        assert!(out[1].is_none());
+        assert!(out[2].is_some());
+    }
+
+    #[test]
+    fn constant_bodies_yield_the_body() {
+        // Every bar closes 1.5 above its open -> Qstick converges to 1.5.
+        let mut q = Qstick::new(4).unwrap();
+        let candles: Vec<Candle> = (0..10).map(|i| candle(10.0, 11.5, i)).collect();
+        let out = q.batch(&candles);
+        assert_relative_eq!(out.last().unwrap().unwrap(), 1.5, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn selling_pressure_is_negative() {
+        let mut q = Qstick::new(3).unwrap();
+        let candles: Vec<Candle> = (0..6).map(|i| candle(11.0, 10.0, i)).collect();
+        let last = q.batch(&candles).last().unwrap().unwrap();
+        assert!(last < 0.0, "qstick {last} should be negative");
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut q = Qstick::new(3).unwrap();
+        let candles: Vec<Candle> = (0..6).map(|i| candle(10.0, 11.0, i)).collect();
+        q.batch(&candles);
+        assert!(q.is_ready());
+        q.reset();
+        assert!(!q.is_ready());
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let candles: Vec<Candle> = (0..40_i64)
+            .map(|i| {
+                candle(
+                    100.0 + (i as f64 * 0.3).sin(),
+                    100.0 + (i as f64 * 0.4).cos(),
+                    i,
+                )
+            })
+            .collect();
+        let mut a = Qstick::new(7).unwrap();
+        let mut b = Qstick::new(7).unwrap();
+        assert_eq!(
+            a.batch(&candles),
+            candles.iter().map(|c| b.update(*c)).collect::<Vec<_>>()
+        );
+    }
+}
@@ -0,0 +1,194 @@
+//! Quartile Bands — rolling 25th / 50th / 75th percentile envelope.
+
+use std::collections::VecDeque;
+
+use crate::error::{Error, Result};
+use crate::indicators::rolling_quantile::quantile_sorted;
+use crate::traits::Indicator;
+
+/// Quartile Bands output.
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub struct QuartileBandsOutput {
+    /// Upper band: the rolling third quartile (75th percentile, `Q3`).
+    pub upper: f64,
+    /// Middle line: the rolling median (50th percentile, `Q2`).
+    pub middle: f64,
+    /// Lower band: the rolling first quartile (25th percentile, `Q1`).
+    pub lower: f64,
+}
+
+/// Quartile Bands: a distribution-based envelope drawn at the rolling quartiles.
+///
+/// ```text
+/// lower  = Q1  = 25th percentile of the last `period` values
+/// middle = Q2  = 50th percentile (median)
+/// upper  = Q3  = 75th percentile
+/// ```
+///
+/// Quantiles use the type-7 (`NumPy`/`R-7`) linear interpolation shared with
+/// [`RollingQuantile`](crate::RollingQuantile). Where Bollinger Bands assume an
+/// approximately normal distribution and size the envelope by the mean and
+/// standard deviation, Quartile Bands are fully **non-parametric**: the band
+/// edges are order statistics, so a single outlier shifts at most one rank
+/// rather than inflating the whole width, and the inter-quartile span between
+/// the bands is exactly the [`RollingIqr`](crate::RollingIqr). The middle line
+/// is the robust median rather than the mean, so it is unmoved by spikes.
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Indicator, QuartileBands};
+///
+/// let mut indicator = QuartileBands::new(20).unwrap();
+/// let mut last = None;
+/// for i in 0..40 {
+///     last = indicator.update(100.0 + f64::from(i));
+/// }
+/// assert!(last.is_some());
+/// ```
+#[derive(Debug, Clone)]
+pub struct QuartileBands {
+    period: usize,
+    window: VecDeque<f64>,
+    scratch: Vec<f64>,
+}
+
+impl QuartileBands {
+    /// Construct new Quartile Bands.
+    ///
+    /// # Errors
+    /// Returns [`Error::PeriodZero`] if `period == 0`.
+    pub fn new(period: usize) -> Result<Self> {
+        if period == 0 {
+            return Err(Error::PeriodZero);
+        }
+        Ok(Self {
+            period,
+            window: VecDeque::with_capacity(period),
+            scratch: Vec::with_capacity(period),
+        })
+    }
+
+    /// Configured period.
+    pub const fn period(&self) -> usize {
+        self.period
+    }
+}
+
+impl Indicator for QuartileBands {
+    type Input = f64;
+    type Output = QuartileBandsOutput;
+
+    fn update(&mut self, value: f64) -> Option<QuartileBandsOutput> {
+        if self.window.len() == self.period {
+            self.window.pop_front();
+        }
+        self.window.push_back(value);
+        if self.window.len() < self.period {
+            return None;
+        }
+        self.scratch.clear();
+        self.scratch.extend(self.window.iter().copied());
+        self.scratch.sort_by(f64::total_cmp);
+        Some(QuartileBandsOutput {
+            upper: quantile_sorted(&self.scratch, 0.75),
+            middle: quantile_sorted(&self.scratch, 0.5),
+            lower: quantile_sorted(&self.scratch, 0.25),
+        })
+    }
+
+    fn reset(&mut self) {
+        self.window.clear();
+        self.scratch.clear();
+    }
+
+    fn warmup_period(&self) -> usize {
+        self.period
+    }
+
+    fn is_ready(&self) -> bool {
+        self.window.len() == self.period
+    }
+
+    fn name(&self) -> &'static str {
+        "QuartileBands"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    #[test]
+    fn rejects_zero_period() {
+        assert!(matches!(QuartileBands::new(0), Err(Error::PeriodZero)));
+        assert!(QuartileBands::new(1).is_ok());
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let qb = QuartileBands::new(20).unwrap();
+        assert_eq!(qb.period(), 20);
+        assert_eq!(qb.warmup_period(), 20);
+        assert_eq!(qb.name(), "QuartileBands");
+        assert!(!qb.is_ready());
+    }
+
+    #[test]
+    fn warms_up_then_emits() {
+        let mut qb = QuartileBands::new(4).unwrap();
+        assert!(qb.update(10.0).is_none());
+        assert!(qb.update(20.0).is_none());
+        assert!(qb.update(30.0).is_none());
+        assert!(qb.update(40.0).is_some());
+        assert!(qb.is_ready());
+    }
+
+    #[test]
+    fn known_quartiles() {
+        // sorted [10,20,30,40]:
+        //   Q1 h=(4-1)*0.25=0.75 -> 10 + 0.75*10 = 17.5
+        //   Q2 h=1.5            -> 20 + 0.5*10  = 25.0
+        //   Q3 h=2.25           -> 30 + 0.25*10 = 32.5
+        let mut qb = QuartileBands::new(4).unwrap();
+        let out = qb.batch(&[40.0, 30.0, 20.0, 10.0]);
+        let last = out[3].unwrap();
+        assert_relative_eq!(last.lower, 17.5, epsilon = 1e-9);
+        assert_relative_eq!(last.middle, 25.0, epsilon = 1e-9);
+        assert_relative_eq!(last.upper, 32.5, epsilon = 1e-9);
+    }
+
+    #[test]
+    fn median_robust_to_outlier() {
+        // A single spike shifts the mean a lot but the median by at most one rank.
+        let mut qb = QuartileBands::new(5).unwrap();
+        let out = qb.batch(&[1.0, 2.0, 3.0, 4.0, 1000.0]);
+        assert_relative_eq!(out[4].unwrap().middle, 3.0, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn rolling_window_evicts_oldest() {
+        // Eight values through a period-4 window: only the last four survive,
+        // reproducing the `known_quartiles` window.
+        let mut qb = QuartileBands::new(4).unwrap();
+        let out = qb.batch(&[1.0, 2.0, 3.0, 4.0, 40.0, 30.0, 20.0, 10.0]);
+        let last = out[7].unwrap();
+        assert_relative_eq!(last.lower, 17.5, epsilon = 1e-9);
+        assert_relative_eq!(last.middle, 25.0, epsilon = 1e-9);
+        assert_relative_eq!(last.upper, 32.5, epsilon = 1e-9);
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut qb = QuartileBands::new(4).unwrap();
+        for v in [10.0, 20.0, 30.0, 40.0] {
+            qb.update(v);
+        }
+        assert!(qb.is_ready());
+        qb.reset();
+        assert!(!qb.is_ready());
+        assert!(qb.update(10.0).is_none());
+    }
+}
@@ -0,0 +1,240 @@
+//! Realized Volatility from the sum of squared log returns.
+
+use std::collections::VecDeque;
+
+use crate::error::{Error, Result};
+use crate::traits::Indicator;
+
+/// Realized Volatility — the square root of the sum of squared log returns over
+/// the trailing `period` bars.
+///
+/// ```text
+/// r_t = ln(price_t / price_{t−1})
+/// RV  = √( Σ r_t²  over the last `period` returns )
+/// ```
+///
+/// Unlike [`HistoricalVolatility`](crate::HistoricalVolatility) — which reports
+/// the *annualised sample standard deviation* of log returns (mean-centred,
+/// divided by `n − 1`, scaled by `√trading_periods` and ×100) — realized
+/// volatility is the **raw, un-centred, un-annualised** quadratic variation
+/// estimator used in high-frequency econometrics. It makes no Gaussian
+/// assumption and no mean subtraction: it simply accumulates squared returns,
+/// which converges to the integrated variance of the price path as the
+/// sampling frequency rises. Multiply by `√trading_periods` yourself if an
+/// annual figure is wanted.
+///
+/// Non-finite and non-positive prices are ignored (the log return would be
+/// undefined): the tick is dropped, state is left untouched, and the last
+/// value is returned.
+///
+/// Each `update` is O(1): a running sum of squared returns is maintained over
+/// the rolling window.
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Indicator, RealizedVolatility};
+///
+/// let mut indicator = RealizedVolatility::new(20).unwrap();
+/// let mut last = None;
+/// for i in 0..80 {
+///     last = indicator.update(100.0 + (f64::from(i) * 0.3).sin() * 5.0);
+/// }
+/// assert!(last.is_some());
+/// ```
+#[derive(Debug, Clone)]
+pub struct RealizedVolatility {
+    period: usize,
+    prev_price: Option<f64>,
+    /// Rolling window of the last `period` log returns.
+    window: VecDeque<f64>,
+    sum_sq: f64,
+    last: Option<f64>,
+}
+
+impl RealizedVolatility {
+    /// Construct a new realized-volatility indicator.
+    ///
+    /// `period` is the number of squared log returns accumulated in the window.
+    ///
+    /// # Errors
+    /// Returns [`Error::PeriodZero`] if `period == 0`.
+    pub fn new(period: usize) -> Result<Self> {
+        if period == 0 {
+            return Err(Error::PeriodZero);
+        }
+        Ok(Self {
+            period,
+            prev_price: None,
+            window: VecDeque::with_capacity(period),
+            sum_sq: 0.0,
+            last: None,
+        })
+    }
+
+    /// Configured period.
+    pub const fn period(&self) -> usize {
+        self.period
+    }
+}
+
+impl Indicator for RealizedVolatility {
+    type Input = f64;
+    type Output = f64;
+
+    fn update(&mut self, input: f64) -> Option<f64> {
+        // Non-finite / non-positive prices are skipped: `ln(input / prev)` is
+        // undefined, so the tick must not enter the return window.
+        if !input.is_finite() || input <= 0.0 {
+            return self.last;
+        }
+        let Some(prev) = self.prev_price else {
+            self.prev_price = Some(input);
+            return None;
+        };
+        self.prev_price = Some(input);
+        // `prev` came from `self.prev_price`, gated by the guard above, so it is
+        // finite and positive — the log return is always well-defined.
+        let r = (input / prev).ln();
+        if self.window.len() == self.period {
+            let old = self.window.pop_front().expect("window is non-empty");
+            self.sum_sq -= old * old;
+        }
+        self.window.push_back(r);
+        self.sum_sq += r * r;
+        if self.window.len() < self.period {
+            return None;
+        }
+        // Floating-point subtraction in the rolling sum can leave a tiny
+        // negative residual when every return is ~0; clamp before the sqrt.
+        let rv = self.sum_sq.max(0.0).sqrt();
+        self.last = Some(rv);
+        Some(rv)
+    }
+
+    fn reset(&mut self) {
+        self.prev_price = None;
+        self.window.clear();
+        self.sum_sq = 0.0;
+        self.last = None;
+    }
+
+    fn warmup_period(&self) -> usize {
+        // The first log return needs a previous price, then the window fills.
+        self.period + 1
+    }
+
+    fn is_ready(&self) -> bool {
+        self.last.is_some()
+    }
+
+    fn name(&self) -> &'static str {
+        "RealizedVolatility"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    #[test]
+    fn rejects_zero_period() {
+        assert!(matches!(RealizedVolatility::new(0), Err(Error::PeriodZero)));
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let rv = RealizedVolatility::new(20).unwrap();
+        assert_eq!(rv.period(), 20);
+        assert_eq!(rv.warmup_period(), 21);
+        assert_eq!(rv.name(), "RealizedVolatility");
+        assert!(!rv.is_ready());
+    }
+
+    #[test]
+    fn first_emission_at_warmup_period() {
+        let mut rv = RealizedVolatility::new(5).unwrap();
+        let out = rv.batch(&(1..=20).map(f64::from).collect::<Vec<_>>());
+        for v in out.iter().take(5) {
+            assert!(v.is_none());
+        }
+        assert!(out[5].is_some());
+    }
+
+    #[test]
+    fn known_value() {
+        // Two equal +10% steps: r = ln(1.1) each. RV = √(2·ln(1.1)²).
+        let mut rv = RealizedVolatility::new(2).unwrap();
+        let out = rv.batch(&[100.0, 110.0, 121.0]);
+        let expected = (2.0 * (1.1_f64).ln().powi(2)).sqrt();
+        assert_relative_eq!(out[2].unwrap(), expected, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn constant_series_yields_zero() {
+        let mut rv = RealizedVolatility::new(10).unwrap();
+        for v in rv.batch(&[100.0; 40]).into_iter().flatten() {
+            assert_relative_eq!(v, 0.0, epsilon = 1e-12);
+        }
+    }
+
+    #[test]
+    fn output_is_non_negative() {
+        let mut rv = RealizedVolatility::new(20).unwrap();
+        let prices: Vec<f64> = (1..=200)
+            .map(|i| 100.0 + (f64::from(i) * 0.3).sin() * 12.0)
+            .collect();
+        for v in rv.batch(&prices).into_iter().flatten() {
+            assert!(
+                v >= 0.0,
+                "realized volatility must be non-negative, got {v}"
+            );
+        }
+    }
+
+    #[test]
+    fn ignores_non_finite_input() {
+        let mut rv = RealizedVolatility::new(5).unwrap();
+        let out = rv.batch(&(1..=20).map(f64::from).collect::<Vec<_>>());
+        let last = *out.last().unwrap();
+        assert!(last.is_some());
+        assert_eq!(rv.update(f64::NAN), last);
+        assert_eq!(rv.update(f64::INFINITY), last);
+    }
+
+    #[test]
+    fn skips_non_positive_prices() {
+        let mut rv = RealizedVolatility::new(5).unwrap();
+        let warmup = rv.batch(&(1..=20).map(f64::from).collect::<Vec<_>>());
+        let baseline = warmup.last().copied().flatten().expect("warmed up");
+        assert_eq!(rv.update(-5.0), Some(baseline));
+        assert_eq!(rv.update(0.0), Some(baseline));
+        // State untouched: a clone advanced by the same real tick agrees.
+        let mut control = rv.clone();
+        let after = rv.update(21.0).expect("ready");
+        assert_eq!(control.update(21.0).expect("ready"), after);
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut rv = RealizedVolatility::new(5).unwrap();
+        rv.batch(&(1..=20).map(f64::from).collect::<Vec<_>>());
+        assert!(rv.is_ready());
+        rv.reset();
+        assert!(!rv.is_ready());
+        assert_eq!(rv.update(1.0), None);
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let prices: Vec<f64> = (1..=120)
+            .map(|i| 100.0 + (f64::from(i) * 0.25).sin() * 9.0)
+            .collect();
+        let batch = RealizedVolatility::new(20).unwrap().batch(&prices);
+        let mut b = RealizedVolatility::new(20).unwrap();
+        let streamed: Vec<_> = prices.iter().map(|p| b.update(*p)).collect();
+        assert_eq!(batch, streamed);
+    }
+}
@@ -0,0 +1,233 @@
+//! Ehlers Reflex — a zero-lag cycle oscillator built on a SuperSmoother prefilter.
+#![allow(clippy::doc_markdown)]
+
+use std::collections::VecDeque;
+
+use crate::error::{Error, Result};
+use crate::indicators::super_smoother::SuperSmoother;
+use crate::traits::Indicator;
+
+/// Ehlers' **Reflex** — a near-zero-lag oscillator that measures how far the
+/// smoothed price has deviated from the straight line connecting its endpoints
+/// over the lookback.
+///
+/// From John Ehlers, "Reflex: A New Zero-Lag Indicator" (*Stocks & Commodities*,
+/// Feb 2020):
+///
+/// ```text
+/// Filt   = SuperSmoother(price, period)
+/// slope  = (Filt[period] − Filt[0]) / period          (line over the window)
+/// sum    = mean over i=1..period of ( Filt[0] + i·slope − Filt[i] )
+/// ms     = 0.04·sum² + 0.96·ms[−1]                     (adaptive normaliser)
+/// Reflex = sum / sqrt(ms)                              (0 if ms == 0)
+/// ```
+///
+/// Reflex fits a straight line across the SuperSmoothed price over `period` bars
+/// and averages the deviation of the curve from that line. Because the line uses
+/// both endpoints, the measure has almost no lag — it crosses zero essentially at
+/// the cycle turns. The adaptive mean-square normaliser rescales the output to a
+/// roughly `±3` range regardless of price, so the same thresholds work on any
+/// instrument. Its sibling [`Trendflex`](crate::Trendflex) uses the deviation from
+/// the *current* value instead of the line, making it trend- rather than
+/// cycle-sensitive.
+///
+/// The first value lands after `period + 1` SuperSmoothed samples. Each `update`
+/// is O(`period`).
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Indicator, Reflex};
+///
+/// let mut indicator = Reflex::new(20).unwrap();
+/// let mut last = None;
+/// for i in 0..120 {
+///     last = indicator.update(100.0 + (f64::from(i) * 0.3).sin() * 5.0);
+/// }
+/// assert!(last.is_some());
+/// ```
+#[derive(Debug, Clone)]
+pub struct Reflex {
+    period: usize,
+    smoother: SuperSmoother,
+    filt: VecDeque<f64>,
+    ms: f64,
+    last: Option<f64>,
+}
+
+impl Reflex {
+    /// Construct a Reflex with the given lookback `period`.
+    ///
+    /// # Errors
+    ///
+    /// Returns [`Error::PeriodZero`] if `period == 0`.
+    pub fn new(period: usize) -> Result<Self> {
+        if period == 0 {
+            return Err(Error::PeriodZero);
+        }
+        Ok(Self {
+            period,
+            smoother: SuperSmoother::new(period)?,
+            filt: VecDeque::with_capacity(period + 1),
+            ms: 0.0,
+            last: None,
+        })
+    }
+
+    /// Configured lookback period.
+    pub const fn period(&self) -> usize {
+        self.period
+    }
+
+    /// Current value if available.
+    pub const fn value(&self) -> Option<f64> {
+        self.last
+    }
+}
+
+impl Indicator for Reflex {
+    type Input = f64;
+    type Output = f64;
+
+    fn update(&mut self, price: f64) -> Option<f64> {
+        if !price.is_finite() {
+            return self.last;
+        }
+        let filt = self.smoother.update(price)?;
+        if self.filt.len() == self.period + 1 {
+            self.filt.pop_front();
+        }
+        self.filt.push_back(filt);
+        if self.filt.len() < self.period + 1 {
+            return None;
+        }
+        // Newest at index `period`, oldest (period bars ago) at index 0.
+        let newest = self.filt[self.period];
+        let oldest = self.filt[0];
+        let slope = (oldest - newest) / self.period as f64;
+        let mut sum = 0.0;
+        for i in 1..=self.period {
+            sum += (newest + i as f64 * slope) - self.filt[self.period - i];
+        }
+        sum /= self.period as f64;
+        self.ms = 0.04 * sum * sum + 0.96 * self.ms;
+        let reflex = if self.ms > 0.0 {
+            sum / self.ms.sqrt()
+        } else {
+            0.0
+        };
+        self.last = Some(reflex);
+        Some(reflex)
+    }
+
+    fn reset(&mut self) {
+        self.smoother.reset();
+        self.filt.clear();
+        self.ms = 0.0;
+        self.last = None;
+    }
+
+    fn warmup_period(&self) -> usize {
+        self.period + 1
+    }
+
+    fn is_ready(&self) -> bool {
+        self.last.is_some()
+    }
+
+    fn name(&self) -> &'static str {
+        "Reflex"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    #[test]
+    fn rejects_zero_period() {
+        assert!(matches!(Reflex::new(0), Err(Error::PeriodZero)));
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let r = Reflex::new(20).unwrap();
+        assert_eq!(r.period(), 20);
+        assert_eq!(r.warmup_period(), 21);
+        assert_eq!(r.name(), "Reflex");
+        assert!(!r.is_ready());
+        assert_eq!(r.value(), None);
+    }
+
+    #[test]
+    fn first_emission_at_warmup_period() {
+        let mut r = Reflex::new(5).unwrap();
+        let xs: Vec<f64> = (0..12)
+            .map(|i| 100.0 + (f64::from(i) * 0.4).sin() * 3.0)
+            .collect();
+        let out = r.batch(&xs);
+        for v in out.iter().take(5) {
+            assert!(v.is_none());
+        }
+        assert!(out[5].is_some());
+    }
+
+    #[test]
+    fn constant_input_is_zero() {
+        // A flat price is exactly its own straight line -> zero deviation -> 0.
+        let mut r = Reflex::new(10).unwrap();
+        for v in r.batch(&[50.0; 100]).into_iter().flatten() {
+            assert_relative_eq!(v, 0.0, epsilon = 1e-9);
+        }
+    }
+
+    #[test]
+    fn cyclic_input_oscillates_around_zero() {
+        let mut r = Reflex::new(20).unwrap();
+        let xs: Vec<f64> = (0..400)
+            .map(|i| 100.0 + (std::f64::consts::TAU * f64::from(i) / 20.0).sin() * 5.0)
+            .collect();
+        let out: Vec<f64> = r.batch(&xs).into_iter().flatten().skip(100).collect();
+        assert!(out.iter().any(|&v| v > 0.5));
+        assert!(out.iter().any(|&v| v < -0.5));
+    }
+
+    #[test]
+    fn ignores_non_finite() {
+        let mut r = Reflex::new(10).unwrap();
+        r.batch(
+            &(0..40)
+                .map(|i| 100.0 + (f64::from(i) * 0.3).sin())
+                .collect::<Vec<_>>(),
+        );
+        let before = r.value();
+        assert_eq!(r.update(f64::NAN), before);
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut r = Reflex::new(10).unwrap();
+        r.batch(
+            &(0..40)
+                .map(|i| 100.0 + (f64::from(i) * 0.3).sin())
+                .collect::<Vec<_>>(),
+        );
+        assert!(r.is_ready());
+        r.reset();
+        assert!(!r.is_ready());
+        assert_eq!(r.value(), None);
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let xs: Vec<f64> = (0..120)
+            .map(|i| 100.0 + (f64::from(i) * 0.25).sin() * 9.0)
+            .collect();
+        let batch = Reflex::new(20).unwrap().batch(&xs);
+        let mut b = Reflex::new(20).unwrap();
+        let streamed: Vec<_> = xs.iter().map(|x| b.update(*x)).collect();
+        assert_eq!(batch, streamed);
+    }
+}
@@ -0,0 +1,307 @@
+//! Regime Label — volatility-quantile classification of the current bar.
+
+use std::collections::VecDeque;
+
+use crate::error::{Error, Result};
+use crate::indicators::rolling_quantile::quantile_sorted;
+use crate::traits::Indicator;
+
+/// Regime Label — a discrete `{−1, 0, +1}` classification of the current
+/// volatility regime by where the latest rolling volatility falls within its
+/// own recent distribution.
+///
+/// ```text
+/// σₜ    = sample stddev of the last `vol_period` log returns
+/// q1,q3 = 25th / 75th percentile of the last `lookback` σ readings
+/// label = −1 if σₜ < q1   (calm regime)
+///         +1 if σₜ > q3   (stressed regime)
+///          0 otherwise    (normal regime)
+/// ```
+///
+/// This is the canonical rolling-volatility-quantile regime split: rather than
+/// thresholding absolute volatility (which is not comparable across instruments
+/// or epochs), it asks whether *today's* volatility is unusually low or high
+/// **relative to its own recent history**. `−1` is a calm regime, `+1` a
+/// stressed / high-volatility regime, `0` the normal middle. Because the latest
+/// reading is included in its own reference window, a freshly elevated
+/// volatility prints `+1` until the window catches up to the new level — it
+/// flags the *transition*, not just the absolute level. When the recent
+/// volatilities are all equal (`q1 == q3`, e.g. a constant drift) there is no
+/// spread to classify against and the label is `0`.
+///
+/// Each `update` is `O(vol_period + lookback log lookback)`. Non-finite and
+/// non-positive prices are ignored.
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Indicator, RegimeLabel};
+///
+/// let mut indicator = RegimeLabel::new(5, 20).unwrap();
+/// let mut last = None;
+/// for i in 0..60 {
+///     last = indicator.update(100.0 + (f64::from(i) * 0.5).sin());
+/// }
+/// assert!(last.is_some());
+/// ```
+#[derive(Debug, Clone)]
+pub struct RegimeLabel {
+    vol_period: usize,
+    lookback: usize,
+    prev_price: Option<f64>,
+    /// Trailing window of the last `vol_period` log returns.
+    ret_window: VecDeque<f64>,
+    ret_sum: f64,
+    ret_sum_sq: f64,
+    /// Trailing window of the last `lookback` volatility readings.
+    vol_window: VecDeque<f64>,
+    /// Reusable scratch buffer for the quantile sort.
+    scratch: Vec<f64>,
+    last: Option<f64>,
+}
+
+impl RegimeLabel {
+    /// Construct a new Regime Label classifier.
+    ///
+    /// `vol_period` is the window for the rolling volatility; `lookback` is the
+    /// window of volatility readings whose quartiles set the regime bands.
+    ///
+    /// # Errors
+    /// Returns [`Error::InvalidPeriod`] if `vol_period < 2` (the sample standard
+    /// deviation needs at least two returns) or if `lookback < 2` (the quartile
+    /// split needs at least two readings).
+    pub fn new(vol_period: usize, lookback: usize) -> Result<Self> {
+        if vol_period < 2 {
+            return Err(Error::InvalidPeriod {
+                message: "regime label needs vol_period >= 2",
+            });
+        }
+        if lookback < 2 {
+            return Err(Error::InvalidPeriod {
+                message: "regime label needs lookback >= 2",
+            });
+        }
+        Ok(Self {
+            vol_period,
+            lookback,
+            prev_price: None,
+            ret_window: VecDeque::with_capacity(vol_period),
+            ret_sum: 0.0,
+            ret_sum_sq: 0.0,
+            vol_window: VecDeque::with_capacity(lookback),
+            scratch: Vec::with_capacity(lookback),
+            last: None,
+        })
+    }
+
+    /// Configured `(vol_period, lookback)`.
+    pub const fn params(&self) -> (usize, usize) {
+        (self.vol_period, self.lookback)
+    }
+}
+
+impl Indicator for RegimeLabel {
+    type Input = f64;
+    type Output = f64;
+
+    fn update(&mut self, input: f64) -> Option<f64> {
+        if !input.is_finite() || input <= 0.0 {
+            return self.last;
+        }
+        let Some(prev) = self.prev_price else {
+            self.prev_price = Some(input);
+            return None;
+        };
+        self.prev_price = Some(input);
+        let r = (input / prev).ln();
+        // Roll the return window and its running moments.
+        if self.ret_window.len() == self.vol_period {
+            let old = self.ret_window.pop_front().expect("non-empty");
+            self.ret_sum -= old;
+            self.ret_sum_sq -= old * old;
+        }
+        self.ret_window.push_back(r);
+        self.ret_sum += r;
+        self.ret_sum_sq += r * r;
+        if self.ret_window.len() < self.vol_period {
+            return None;
+        }
+        let n = self.vol_period as f64;
+        let mean = self.ret_sum / n;
+        let var = ((self.ret_sum_sq - n * mean * mean) / (n - 1.0)).max(0.0);
+        let vol = var.sqrt();
+        // Roll the volatility window.
+        if self.vol_window.len() == self.lookback {
+            self.vol_window.pop_front();
+        }
+        self.vol_window.push_back(vol);
+        if self.vol_window.len() < self.lookback {
+            return None;
+        }
+        // Classify the latest volatility against the quartiles of the window.
+        self.scratch.clear();
+        self.scratch.extend(self.vol_window.iter().copied());
+        self.scratch.sort_by(f64::total_cmp);
+        let q1 = quantile_sorted(&self.scratch, 0.25);
+        let q3 = quantile_sorted(&self.scratch, 0.75);
+        let label = if vol < q1 {
+            -1.0
+        } else if vol > q3 {
+            1.0
+        } else {
+            0.0
+        };
+        self.last = Some(label);
+        Some(label)
+    }
+
+    fn reset(&mut self) {
+        self.prev_price = None;
+        self.ret_window.clear();
+        self.ret_sum = 0.0;
+        self.ret_sum_sq = 0.0;
+        self.vol_window.clear();
+        self.scratch.clear();
+        self.last = None;
+    }
+
+    fn warmup_period(&self) -> usize {
+        // One price seeds `prev`, `vol_period` returns yield the first vol, then
+        // `lookback` vols fill the regime window.
+        self.vol_period + self.lookback
+    }
+
+    fn is_ready(&self) -> bool {
+        self.last.is_some()
+    }
+
+    fn name(&self) -> &'static str {
+        "RegimeLabel"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+
+    #[test]
+    fn rejects_bad_periods() {
+        assert!(matches!(
+            RegimeLabel::new(1, 20),
+            Err(Error::InvalidPeriod { .. })
+        ));
+        assert!(matches!(
+            RegimeLabel::new(5, 1),
+            Err(Error::InvalidPeriod { .. })
+        ));
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let rl = RegimeLabel::new(5, 20).unwrap();
+        assert_eq!(rl.params(), (5, 20));
+        assert_eq!(rl.warmup_period(), 25);
+        assert_eq!(rl.name(), "RegimeLabel");
+        assert!(!rl.is_ready());
+    }
+
+    #[test]
+    fn detects_stressed_regime_on_volatility_spike() {
+        // Calm warmup, then a burst of large moves: the elevated volatility
+        // prints +1 while the lookback window still holds the calm readings.
+        let mut rl = RegimeLabel::new(4, 8).unwrap();
+        let mut prices: Vec<f64> = (0..24)
+            .map(|i| 100.0 + (f64::from(i) * 0.7).sin() * 0.2)
+            .collect();
+        let mut base = *prices.last().unwrap();
+        for i in 0..8 {
+            base *= if i % 2 == 0 { 1.08 } else { 0.93 };
+            prices.push(base);
+        }
+        let out = rl.batch(&prices);
+        assert!(
+            out.iter().flatten().any(|&v| v == 1.0),
+            "expected a stressed (+1) regime label"
+        );
+    }
+
+    #[test]
+    fn detects_calm_regime_after_volatility_drop() {
+        // Volatile warmup, then a calm tail: the depressed volatility prints -1.
+        let mut rl = RegimeLabel::new(4, 8).unwrap();
+        let mut prices: Vec<f64> = Vec::new();
+        let mut base = 100.0;
+        for i in 0..24 {
+            base *= if i % 2 == 0 { 1.05 } else { 0.96 };
+            prices.push(base);
+        }
+        for i in 0..12 {
+            prices.push(base + (f64::from(i) * 0.7).sin() * 0.05);
+        }
+        let out = rl.batch(&prices);
+        assert!(
+            out.iter().flatten().any(|&v| v == -1.0),
+            "expected a calm (-1) regime label"
+        );
+    }
+
+    #[test]
+    fn zero_volatility_is_neutral() {
+        // A constant price has exactly-zero returns => zero volatility on every
+        // window => q1 == q3 == 0 => neutral 0 throughout. (A geometric drift is
+        // *conceptually* constant-vol too, but floating-point rounding of the
+        // log returns leaves ~1e-16 dispersion, so the exactly-flat series is
+        // the clean way to pin the q1 == q3 branch.)
+        let mut rl = RegimeLabel::new(4, 8).unwrap();
+        for v in rl.batch(&[100.0; 40]).into_iter().flatten() {
+            assert_eq!(v, 0.0);
+        }
+    }
+
+    #[test]
+    fn output_is_ternary() {
+        let mut rl = RegimeLabel::new(5, 20).unwrap();
+        let prices: Vec<f64> = (0..300)
+            .map(|i| 100.0 + (f64::from(i) * 0.3).sin() * (1.0 + (f64::from(i) * 0.05).sin() * 5.0))
+            .collect();
+        for v in rl.batch(&prices).into_iter().flatten() {
+            assert!(v == -1.0 || v == 0.0 || v == 1.0, "non-ternary label {v}");
+        }
+    }
+
+    #[test]
+    fn ignores_non_finite_and_non_positive() {
+        let mut rl = RegimeLabel::new(4, 6).unwrap();
+        let prices: Vec<f64> = (0..40)
+            .map(|i| 100.0 + (f64::from(i) * 0.5).sin() * 2.0)
+            .collect();
+        let out = rl.batch(&prices);
+        let last = *out.last().unwrap();
+        assert!(last.is_some());
+        assert_eq!(rl.update(f64::NAN), last);
+        assert_eq!(rl.update(-1.0), last);
+        assert_eq!(rl.update(0.0), last);
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut rl = RegimeLabel::new(4, 6).unwrap();
+        rl.batch(&(1..=40).map(f64::from).collect::<Vec<_>>());
+        assert!(rl.is_ready());
+        rl.reset();
+        assert!(!rl.is_ready());
+        assert_eq!(rl.update(1.0), None);
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let prices: Vec<f64> = (1..=160)
+            .map(|i| 100.0 + (f64::from(i) * 0.25).sin() * 4.0)
+            .collect();
+        let batch = RegimeLabel::new(5, 20).unwrap().batch(&prices);
+        let mut b = RegimeLabel::new(5, 20).unwrap();
+        let streamed: Vec<_> = prices.iter().map(|p| b.update(*p)).collect();
+        assert_eq!(batch, streamed);
+    }
+}
@@ -0,0 +1,276 @@
+//! Relative Momentum Index (RMI).
+
+use std::collections::VecDeque;
+
+use crate::error::{Error, Result};
+use crate::traits::Indicator;
+
+/// Relative Momentum Index — RSI generalised to a multi-bar momentum lookback.
+///
+/// Wilder's [`Rsi`](crate::Rsi) compares each close to the *previous* close.
+/// The RMI (Roger Altman, 1993) compares it to the close `momentum` bars ago,
+/// then applies the same Wilder-smoothed up/down accumulator over `period`:
+///
+/// ```text
+/// change_t = close_t - close_{t-momentum}
+/// gain     = max(change, 0),  loss = max(-change, 0)
+/// avg_gain, avg_loss = Wilder-smoothed over `period`
+/// RMI      = 100 * avg_gain / (avg_gain + avg_loss)
+/// ```
+///
+/// `momentum = 1` reduces the RMI exactly to the RSI. Larger `momentum` makes
+/// the oscillator smoother and slower to flip, holding overbought/oversold
+/// readings longer in a trend. Output is bounded in `[0, 100]`; a flat market
+/// (no gains and no losses) returns the neutral `50`.
+///
+/// The first value lands after `momentum + period` inputs: `momentum` to fill
+/// the lookback, then `period` changes to seed Wilder's averages.
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Indicator, Rmi};
+///
+/// let mut indicator = Rmi::new(14, 5).unwrap();
+/// let mut last = None;
+/// for i in 0..80 {
+///     last = indicator.update(100.0 + (f64::from(i) * 0.2).sin() * 5.0);
+/// }
+/// assert!(last.is_some());
+/// ```
+#[derive(Debug, Clone)]
+pub struct Rmi {
+    period: usize,
+    momentum: usize,
+    /// The last `momentum` prices, oldest at the front.
+    window: VecDeque<f64>,
+    seed_gains: Vec<f64>,
+    seed_losses: Vec<f64>,
+    avg_gain: Option<f64>,
+    avg_loss: Option<f64>,
+    last_value: Option<f64>,
+}
+
+impl Rmi {
+    /// Construct an RMI with the given smoothing `period` and `momentum`
+    /// lookback.
+    ///
+    /// # Errors
+    ///
+    /// Returns [`Error::PeriodZero`] if either `period` or `momentum` is `0`.
+    pub fn new(period: usize, momentum: usize) -> Result<Self> {
+        if period == 0 || momentum == 0 {
+            return Err(Error::PeriodZero);
+        }
+        Ok(Self {
+            period,
+            momentum,
+            window: VecDeque::with_capacity(momentum),
+            seed_gains: Vec::with_capacity(period),
+            seed_losses: Vec::with_capacity(period),
+            avg_gain: None,
+            avg_loss: None,
+            last_value: None,
+        })
+    }
+
+    /// Configured smoothing period.
+    pub const fn period(&self) -> usize {
+        self.period
+    }
+
+    /// Configured momentum lookback.
+    pub const fn momentum(&self) -> usize {
+        self.momentum
+    }
+
+    /// Current value if available.
+    pub const fn value(&self) -> Option<f64> {
+        self.last_value
+    }
+
+    fn rmi_from_avgs(avg_gain: f64, avg_loss: f64) -> f64 {
+        let denom = avg_gain + avg_loss;
+        if denom == 0.0 {
+            50.0
+        } else {
+            // Ratio first, then scale, so `100 * g / g` cannot round above 100.
+            100.0 * (avg_gain / denom)
+        }
+    }
+}
+
+impl Indicator for Rmi {
+    type Input = f64;
+    type Output = f64;
+
+    fn update(&mut self, input: f64) -> Option<f64> {
+        if !input.is_finite() {
+            return self.last_value;
+        }
+        if self.window.len() < self.momentum {
+            // Still filling the momentum lookback; no change to measure yet.
+            self.window.push_back(input);
+            return None;
+        }
+        let past = self.window.pop_front().expect("window full");
+        self.window.push_back(input);
+
+        let change = input - past;
+        let gain = if change > 0.0 { change } else { 0.0 };
+        let loss = if change < 0.0 { -change } else { 0.0 };
+
+        if let (Some(ag), Some(al)) = (self.avg_gain, self.avg_loss) {
+            let n = self.period as f64;
+            let new_ag = (ag * (n - 1.0) + gain) / n;
+            let new_al = (al * (n - 1.0) + loss) / n;
+            self.avg_gain = Some(new_ag);
+            self.avg_loss = Some(new_al);
+            let v = Self::rmi_from_avgs(new_ag, new_al);
+            self.last_value = Some(v);
+            return Some(v);
+        }
+
+        self.seed_gains.push(gain);
+        self.seed_losses.push(loss);
+        if self.seed_gains.len() == self.period {
+            let ag = self.seed_gains.iter().sum::<f64>() / self.period as f64;
+            let al = self.seed_losses.iter().sum::<f64>() / self.period as f64;
+            self.avg_gain = Some(ag);
+            self.avg_loss = Some(al);
+            let v = Self::rmi_from_avgs(ag, al);
+            self.last_value = Some(v);
+            return Some(v);
+        }
+        None
+    }
+
+    fn reset(&mut self) {
+        self.window.clear();
+        self.seed_gains.clear();
+        self.seed_losses.clear();
+        self.avg_gain = None;
+        self.avg_loss = None;
+        self.last_value = None;
+    }
+
+    fn warmup_period(&self) -> usize {
+        self.momentum + self.period
+    }
+
+    fn is_ready(&self) -> bool {
+        self.last_value.is_some()
+    }
+
+    fn name(&self) -> &'static str {
+        "RMI"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::indicators::Rsi;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    #[test]
+    fn rejects_zero_params() {
+        assert!(matches!(Rmi::new(0, 5), Err(Error::PeriodZero)));
+        assert!(matches!(Rmi::new(14, 0), Err(Error::PeriodZero)));
+    }
+
+    /// Cover the const accessors `period` + `momentum` + `value` and the
+    /// Indicator-impl `warmup_period` + `name`.
+    #[test]
+    fn accessors_and_metadata() {
+        let rmi = Rmi::new(14, 5).unwrap();
+        assert_eq!(rmi.period(), 14);
+        assert_eq!(rmi.momentum(), 5);
+        assert_eq!(rmi.value(), None);
+        assert_eq!(rmi.warmup_period(), 19);
+        assert_eq!(rmi.name(), "RMI");
+    }
+
+    #[test]
+    fn momentum_one_equals_rsi() {
+        // With momentum = 1 the RMI is exactly Wilder's RSI.
+        let prices: Vec<f64> = (0..60)
+            .map(|i| 100.0 + (f64::from(i) * 0.4).sin() * 8.0)
+            .collect();
+        let mut rmi = Rmi::new(14, 1).unwrap();
+        let mut rsi = Rsi::new(14).unwrap();
+        for (i, &p) in prices.iter().enumerate() {
+            let got = rmi.update(p);
+            let want = rsi.update(p);
+            assert_eq!(got.is_some(), want.is_some(), "readiness mismatch at {i}");
+            if let (Some(a), Some(b)) = (got, want) {
+                assert_relative_eq!(a, b, epsilon = 1e-9);
+            }
+        }
+    }
+
+    #[test]
+    fn warmup_then_emits() {
+        // momentum + period = 3 + 2 = 5 inputs before the first value.
+        let mut rmi = Rmi::new(2, 3).unwrap();
+        let out = rmi.batch(&[1.0, 2.0, 3.0, 4.0, 5.0, 6.0]);
+        for (i, v) in out.iter().enumerate().take(4) {
+            assert!(v.is_none(), "index {i} must be None during warmup");
+        }
+        assert!(out[4].is_some(), "first value at warmup_period - 1");
+    }
+
+    #[test]
+    fn pure_uptrend_is_one_hundred() {
+        // Every momentum-spaced change is positive -> avg_loss 0 -> RMI 100.
+        let prices: Vec<f64> = (1..=40).map(f64::from).collect();
+        let mut rmi = Rmi::new(5, 3).unwrap();
+        let last = rmi.batch(&prices).into_iter().flatten().last().unwrap();
+        assert_relative_eq!(last, 100.0, epsilon = 1e-9);
+    }
+
+    #[test]
+    fn flat_market_is_neutral() {
+        // No change -> no gains and no losses -> neutral 50.
+        let mut rmi = Rmi::new(3, 2).unwrap();
+        let last = rmi.batch(&[7.0; 20]).into_iter().flatten().last().unwrap();
+        assert_relative_eq!(last, 50.0, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn ignores_non_finite_input() {
+        let mut rmi = Rmi::new(2, 2).unwrap();
+        let ready = rmi
+            .batch(&[1.0, 2.0, 3.0, 4.0, 5.0])
+            .into_iter()
+            .flatten()
+            .last()
+            .unwrap();
+        assert_eq!(rmi.update(f64::NAN), Some(ready));
+        assert_eq!(rmi.update(f64::INFINITY), Some(ready));
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut rmi = Rmi::new(3, 2).unwrap();
+        rmi.batch(&(1..=20).map(f64::from).collect::<Vec<_>>());
+        assert!(rmi.is_ready());
+        rmi.reset();
+        assert!(!rmi.is_ready());
+        assert_eq!(rmi.update(1.0), None);
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let prices: Vec<f64> = (1..=40)
+            .map(|i| 50.0 + (f64::from(i) * 0.5).sin() * 10.0)
+            .collect();
+        let mut a = Rmi::new(14, 5).unwrap();
+        let mut b = Rmi::new(14, 5).unwrap();
+        assert_eq!(
+            a.batch(&prices),
+            prices.iter().map(|p| b.update(*p)).collect::<Vec<_>>()
+        );
+    }
+}
@@ -0,0 +1,210 @@
+//! Roll Measure — effective spread implied by serial covariance of price changes.
+
+use std::collections::VecDeque;
+
+use crate::microstructure::Trade;
+use crate::traits::Indicator;
+use crate::{Error, Result};
+
+/// Roll Measure — the effective bid-ask spread implied by the negative
+/// first-order serial covariance of trade-price changes (Roll, 1984).
+///
+/// ```text
+/// Δpₜ  = priceₜ − priceₜ₋₁
+/// γ    = sample lag-1 autocovariance of Δp over the last `period` changes
+/// spread = 2 · √(−γ)   if γ < 0,   else 0
+/// ```
+///
+/// Roll's insight: in a frictionless market price changes are serially
+/// uncorrelated, but the *bid-ask bounce* — trades alternating between buying at
+/// the ask and selling at the bid — induces a **negative** autocovariance whose
+/// magnitude pins the spread. The measure recovers an effective spread from
+/// trade prices alone, with no quote data. When the serial covariance is
+/// non-negative (a trending or frictionless tape) the model implies no spread
+/// and the indicator returns `0`.
+///
+/// `Input = Trade` (only the price is used). Each `update` is `O(period)`: the
+/// autocovariance is recomputed from the window of price changes.
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Indicator, Side, Trade, RollMeasure};
+///
+/// let mut roll = RollMeasure::new(20).unwrap();
+/// let mut last = None;
+/// // A clean bid-ask bounce of ±0.5 around 100 implies a spread near 1.0.
+/// for i in 0..40 {
+///     let price = if i % 2 == 0 { 100.0 } else { 101.0 };
+///     last = roll.update(Trade::new(price, 1.0, Side::Buy, 0).unwrap());
+/// }
+/// assert!(last.unwrap() > 0.0);
+/// ```
+#[derive(Debug, Clone)]
+pub struct RollMeasure {
+    period: usize,
+    prev_price: Option<f64>,
+    window: VecDeque<f64>,
+}
+
+impl RollMeasure {
+    /// Construct a new Roll Measure over the given window of price changes.
+    ///
+    /// # Errors
+    /// Returns [`Error::InvalidPeriod`] if `period < 3` — the lag-1
+    /// autocovariance needs at least two consecutive change pairs.
+    pub fn new(period: usize) -> Result<Self> {
+        if period < 3 {
+            return Err(Error::InvalidPeriod {
+                message: "Roll measure needs period >= 3",
+            });
+        }
+        Ok(Self {
+            period,
+            prev_price: None,
+            window: VecDeque::with_capacity(period),
+        })
+    }
+
+    /// Configured period.
+    pub const fn period(&self) -> usize {
+        self.period
+    }
+}
+
+impl Indicator for RollMeasure {
+    type Input = Trade;
+    type Output = f64;
+
+    fn update(&mut self, trade: Trade) -> Option<f64> {
+        let Some(prev) = self.prev_price else {
+            self.prev_price = Some(trade.price);
+            return None;
+        };
+        let change = trade.price - prev;
+        self.prev_price = Some(trade.price);
+        if self.window.len() == self.period {
+            self.window.pop_front();
+        }
+        self.window.push_back(change);
+        if self.window.len() < self.period {
+            return None;
+        }
+        // Sample lag-1 autocovariance of the price changes over the window.
+        let changes: Vec<f64> = self.window.iter().copied().collect();
+        let count = changes.len() as f64;
+        let mean = changes.iter().sum::<f64>() / count;
+        let pairs = (changes.len() - 1) as f64;
+        let mut cov = 0.0;
+        for pair in changes.windows(2) {
+            cov += (pair[0] - mean) * (pair[1] - mean);
+        }
+        cov /= pairs;
+        let spread = if cov < 0.0 { 2.0 * (-cov).sqrt() } else { 0.0 };
+        Some(spread)
+    }
+
+    fn reset(&mut self) {
+        self.prev_price = None;
+        self.window.clear();
+    }
+
+    fn warmup_period(&self) -> usize {
+        self.period + 1
+    }
+
+    fn is_ready(&self) -> bool {
+        self.window.len() == self.period
+    }
+
+    fn name(&self) -> &'static str {
+        "RollMeasure"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::microstructure::Side;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    fn trade(price: f64) -> Trade {
+        Trade::new(price, 1.0, Side::Buy, 0).unwrap()
+    }
+
+    #[test]
+    fn rejects_period_below_three() {
+        assert!(matches!(
+            RollMeasure::new(2),
+            Err(Error::InvalidPeriod { .. })
+        ));
+        assert!(RollMeasure::new(3).is_ok());
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let roll = RollMeasure::new(20).unwrap();
+        assert_eq!(roll.period(), 20);
+        assert_eq!(roll.warmup_period(), 21);
+        assert_eq!(roll.name(), "RollMeasure");
+        assert!(!roll.is_ready());
+    }
+
+    #[test]
+    fn bid_ask_bounce_implies_spread() {
+        // Prices bounce 100/101 => Δp alternates +1/-1 => mean 0, lag-1
+        // autocov = -5/(6-1) = -1 over a 6-change window => spread = 2.
+        let mut roll = RollMeasure::new(6).unwrap();
+        let prices: Vec<Trade> = (0..20)
+            .map(|i| trade(if i % 2 == 0 { 100.0 } else { 101.0 }))
+            .collect();
+        let last = roll.batch(&prices).into_iter().flatten().last().unwrap();
+        assert_relative_eq!(last, 2.0, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn trending_prices_imply_no_spread() {
+        // Monotone prices => constant Δp => zero-centred deviations => cov 0
+        // => spread 0.
+        let mut roll = RollMeasure::new(6).unwrap();
+        let prices: Vec<Trade> = (0..20).map(|i| trade(100.0 + f64::from(i))).collect();
+        for v in roll.batch(&prices).into_iter().flatten() {
+            assert_relative_eq!(v, 0.0, epsilon = 1e-12);
+        }
+    }
+
+    #[test]
+    fn output_is_non_negative() {
+        let mut roll = RollMeasure::new(20).unwrap();
+        let prices: Vec<Trade> = (0..200)
+            .map(|i| trade(100.0 + (f64::from(i) * 0.7).sin() * 2.0))
+            .collect();
+        for v in roll.batch(&prices).into_iter().flatten() {
+            assert!(v >= 0.0, "spread must be non-negative, got {v}");
+        }
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut roll = RollMeasure::new(5).unwrap();
+        for i in 0..20 {
+            roll.update(trade(100.0 + f64::from(i % 2)));
+        }
+        assert!(roll.is_ready());
+        roll.reset();
+        assert!(!roll.is_ready());
+        assert_eq!(roll.update(trade(100.0)), None);
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let prices: Vec<Trade> = (0..80)
+            .map(|i| trade(100.0 + (f64::from(i) * 0.6).sin() * 3.0))
+            .collect();
+        let batch = RollMeasure::new(14).unwrap().batch(&prices);
+        let mut b = RollMeasure::new(14).unwrap();
+        let streamed: Vec<_> = prices.iter().map(|t| b.update(*t)).collect();
+        assert_eq!(batch, streamed);
+    }
+}
@@ -0,0 +1,186 @@
+//! Rolling Interquartile Range (IQR) over a trailing window.
+
+use std::collections::VecDeque;
+
+use crate::error::{Error, Result};
+use crate::indicators::rolling_quantile::quantile_sorted;
+use crate::traits::Indicator;
+
+/// Interquartile Range of the last `period` values: `Q3 − Q1`.
+///
+/// ```text
+/// IQR = quantile(0.75) − quantile(0.25)
+/// ```
+///
+/// The IQR is the width of the central 50% of the window — the spread between
+/// the third and first quartiles. It is a robust dispersion measure: unlike the
+/// standard deviation it ignores the extreme tails entirely, so a single spike
+/// barely moves it. That makes it the natural scale for outlier rules (the
+/// classic *Tukey fence* flags points more than `1.5 · IQR` beyond a quartile)
+/// and for volatility-regime splits that must not be dominated by one shock.
+///
+/// Both quartiles use the type-7 / NumPy-default linearly-interpolated
+/// definition, identical to [`RollingQuantile`](crate::RollingQuantile). Each
+/// `update` is O(period log period): the window is copied into a scratch buffer
+/// and sorted once.
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Indicator, RollingIqr};
+///
+/// let mut indicator = RollingIqr::new(20).unwrap();
+/// let mut last = None;
+/// for i in 0..40 {
+///     last = indicator.update(100.0 + f64::from(i));
+/// }
+/// assert!(last.is_some());
+/// ```
+#[derive(Debug, Clone)]
+pub struct RollingIqr {
+    period: usize,
+    window: VecDeque<f64>,
+    /// Reusable scratch buffer to avoid allocating per `update`.
+    scratch: Vec<f64>,
+}
+
+impl RollingIqr {
+    /// Construct a new rolling IQR with the given period.
+    ///
+    /// # Errors
+    /// Returns [`Error::PeriodZero`] if `period == 0`.
+    pub fn new(period: usize) -> Result<Self> {
+        if period == 0 {
+            return Err(Error::PeriodZero);
+        }
+        Ok(Self {
+            period,
+            window: VecDeque::with_capacity(period),
+            scratch: Vec::with_capacity(period),
+        })
+    }
+
+    /// Configured period.
+    pub const fn period(&self) -> usize {
+        self.period
+    }
+}
+
+impl Indicator for RollingIqr {
+    type Input = f64;
+    type Output = f64;
+
+    fn update(&mut self, value: f64) -> Option<f64> {
+        if self.window.len() == self.period {
+            self.window.pop_front();
+        }
+        self.window.push_back(value);
+        if self.window.len() < self.period {
+            return None;
+        }
+        self.scratch.clear();
+        self.scratch.extend(self.window.iter().copied());
+        self.scratch.sort_by(f64::total_cmp);
+        let q1 = quantile_sorted(&self.scratch, 0.25);
+        let q3 = quantile_sorted(&self.scratch, 0.75);
+        Some(q3 - q1)
+    }
+
+    fn reset(&mut self) {
+        self.window.clear();
+        self.scratch.clear();
+    }
+
+    fn warmup_period(&self) -> usize {
+        self.period
+    }
+
+    fn is_ready(&self) -> bool {
+        self.window.len() == self.period
+    }
+
+    fn name(&self) -> &'static str {
+        "RollingIqr"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    #[test]
+    fn rejects_zero_period() {
+        assert!(matches!(RollingIqr::new(0), Err(Error::PeriodZero)));
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let iqr = RollingIqr::new(14).unwrap();
+        assert_eq!(iqr.period(), 14);
+        assert_eq!(iqr.warmup_period(), 14);
+        assert_eq!(iqr.name(), "RollingIqr");
+        assert!(!iqr.is_ready());
+    }
+
+    #[test]
+    fn reference_value() {
+        // sorted [10,20,30,40,50]: Q1 = q(0.25)= 10 + (4*0.25)*(...)= h=1.0 →20,
+        // Q3 = q(0.75): h = 4*0.75 = 3.0 → 40. IQR = 40 - 20 = 20.
+        let mut iqr = RollingIqr::new(5).unwrap();
+        let out = iqr.batch(&[50.0, 40.0, 30.0, 20.0, 10.0]);
+        assert_relative_eq!(out[4].unwrap(), 20.0, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn constant_series_yields_zero() {
+        let mut iqr = RollingIqr::new(8).unwrap();
+        for v in iqr.batch(&[42.0; 20]).into_iter().flatten() {
+            assert_relative_eq!(v, 0.0, epsilon = 1e-12);
+        }
+    }
+
+    #[test]
+    fn output_is_non_negative() {
+        let mut iqr = RollingIqr::new(20).unwrap();
+        let prices: Vec<f64> = (1..=200)
+            .map(|i| 100.0 + (f64::from(i) * 0.3).sin() * 12.0)
+            .collect();
+        for v in iqr.batch(&prices).into_iter().flatten() {
+            assert!(v >= 0.0, "IQR must be non-negative, got {v}");
+        }
+    }
+
+    #[test]
+    fn ignores_single_extreme_outlier() {
+        // 19 tightly-clustered values plus one huge spike: the central 50%
+        // is unaffected, so the IQR stays small (well below the spike scale).
+        let mut iqr = RollingIqr::new(20).unwrap();
+        let mut prices = vec![5.0; 19];
+        prices.push(10_000.0);
+        let last = iqr.batch(&prices).into_iter().flatten().last().unwrap();
+        assert!(last < 1.0, "spike leaked into IQR: {last}");
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut iqr = RollingIqr::new(5).unwrap();
+        iqr.batch(&[1.0, 2.0, 3.0, 4.0, 5.0]);
+        assert!(iqr.is_ready());
+        iqr.reset();
+        assert!(!iqr.is_ready());
+        assert_eq!(iqr.update(1.0), None);
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let prices: Vec<f64> = (0..60)
+            .map(|i| 100.0 + (f64::from(i) * 0.3).sin() * 5.0)
+            .collect();
+        let batch = RollingIqr::new(14).unwrap().batch(&prices);
+        let mut b = RollingIqr::new(14).unwrap();
+        let streamed: Vec<_> = prices.iter().map(|p| b.update(*p)).collect();
+        assert_eq!(batch, streamed);
+    }
+}
@@ -0,0 +1,261 @@
+//! Rolling Min-Max Scaler — normalises the latest value to `[0, 1]` over a window.
+
+use std::collections::VecDeque;
+
+use crate::error::{Error, Result};
+use crate::traits::Indicator;
+
+/// Rolling Min-Max Scaler — maps the current value onto `[0, 1]` relative to the
+/// minimum and maximum of the trailing window.
+///
+/// ```text
+/// scaled = (x − min(window)) / (max(window) − min(window))
+/// ```
+///
+/// This is the streaming form of scikit-learn's `MinMaxScaler` applied over a
+/// sliding window: `0` means the value is the lowest in the window, `1` the
+/// highest, `0.5` the midpoint of the range. It is the engine behind oscillators
+/// like the Stochastic %K and a handy normaliser for feeding any indicator into a
+/// bounded model input. Because it rescales to the window's own range it is
+/// scale-free across instruments.
+///
+/// The output is in `[0, 1]`. A flat window (`max == min`) has no range to scale
+/// against and returns the neutral `0.5`. The first value lands after `period`
+/// inputs; each `update` scans the window in O(`period`).
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Indicator, RollingMinMaxScaler};
+///
+/// let mut indicator = RollingMinMaxScaler::new(14).unwrap();
+/// let mut last = None;
+/// for i in 0..40 {
+///     last = indicator.update(100.0 + (f64::from(i) * 0.3).sin() * 5.0);
+/// }
+/// assert!(last.is_some());
+/// ```
+#[derive(Debug, Clone)]
+pub struct RollingMinMaxScaler {
+    period: usize,
+    window: VecDeque<f64>,
+    last: Option<f64>,
+}
+
+impl RollingMinMaxScaler {
+    /// Construct a rolling min-max scaler over `period` values.
+    ///
+    /// # Errors
+    ///
+    /// Returns [`Error::PeriodZero`] if `period == 0` and
+    /// [`Error::InvalidPeriod`] if `period < 2` (a range needs two points).
+    pub fn new(period: usize) -> Result<Self> {
+        if period == 0 {
+            return Err(Error::PeriodZero);
+        }
+        if period < 2 {
+            return Err(Error::InvalidPeriod {
+                message: "min-max scaler needs period >= 2",
+            });
+        }
+        Ok(Self {
+            period,
+            window: VecDeque::with_capacity(period),
+            last: None,
+        })
+    }
+
+    /// Configured window length.
+    pub const fn period(&self) -> usize {
+        self.period
+    }
+
+    /// Current value if available.
+    pub const fn value(&self) -> Option<f64> {
+        self.last
+    }
+}
+
+impl Indicator for RollingMinMaxScaler {
+    type Input = f64;
+    type Output = f64;
+
+    fn update(&mut self, input: f64) -> Option<f64> {
+        if !input.is_finite() {
+            return self.last;
+        }
+        if self.window.len() == self.period {
+            self.window.pop_front();
+        }
+        self.window.push_back(input);
+        if self.window.len() < self.period {
+            return None;
+        }
+        let mut min = f64::INFINITY;
+        let mut max = f64::NEG_INFINITY;
+        for &v in &self.window {
+            min = min.min(v);
+            max = max.max(v);
+        }
+        let range = max - min;
+        let scaled = if range > 0.0 {
+            (input - min) / range
+        } else {
+            0.5
+        };
+        self.last = Some(scaled);
+        Some(scaled)
+    }
+
+    fn reset(&mut self) {
+        self.window.clear();
+        self.last = None;
+    }
+
+    fn warmup_period(&self) -> usize {
+        self.period
+    }
+
+    fn is_ready(&self) -> bool {
+        self.last.is_some()
+    }
+
+    fn name(&self) -> &'static str {
+        "RollingMinMaxScaler"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    #[test]
+    fn rejects_invalid_period() {
+        assert!(matches!(
+            RollingMinMaxScaler::new(0),
+            Err(Error::PeriodZero)
+        ));
+        assert!(matches!(
+            RollingMinMaxScaler::new(1),
+            Err(Error::InvalidPeriod { .. })
+        ));
+        assert!(RollingMinMaxScaler::new(2).is_ok());
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let s = RollingMinMaxScaler::new(14).unwrap();
+        assert_eq!(s.period(), 14);
+        assert_eq!(s.warmup_period(), 14);
+        assert_eq!(s.name(), "RollingMinMaxScaler");
+        assert!(!s.is_ready());
+        assert_eq!(s.value(), None);
+    }
+
+    #[test]
+    fn first_emission_at_warmup_period() {
+        let mut s = RollingMinMaxScaler::new(4).unwrap();
+        let out = s.batch(&[1.0, 2.0, 3.0, 4.0, 5.0]);
+        for v in out.iter().take(3) {
+            assert!(v.is_none());
+        }
+        assert!(out[3].is_some());
+    }
+
+    #[test]
+    fn highest_in_window_is_one() {
+        let mut s = RollingMinMaxScaler::new(4).unwrap();
+        // last value is the highest -> 1.0.
+        let last = s
+            .batch(&[1.0, 2.0, 3.0, 4.0])
+            .into_iter()
+            .flatten()
+            .last()
+            .unwrap();
+        assert_relative_eq!(last, 1.0, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn lowest_in_window_is_zero() {
+        let mut s = RollingMinMaxScaler::new(4).unwrap();
+        let last = s
+            .batch(&[4.0, 3.0, 2.0, 1.0])
+            .into_iter()
+            .flatten()
+            .last()
+            .unwrap();
+        assert_relative_eq!(last, 0.0, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn midpoint_is_half() {
+        let mut s = RollingMinMaxScaler::new(3).unwrap();
+        // window [0, 2, 1]: min 0, max 2, current 1 -> 0.5.
+        let last = s
+            .batch(&[0.0, 2.0, 1.0])
+            .into_iter()
+            .flatten()
+            .last()
+            .unwrap();
+        assert_relative_eq!(last, 0.5, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn flat_window_is_half() {
+        let mut s = RollingMinMaxScaler::new(4).unwrap();
+        let last = s.batch(&[7.0; 8]).into_iter().flatten().last().unwrap();
+        assert_relative_eq!(last, 0.5, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn output_in_range() {
+        let mut s = RollingMinMaxScaler::new(14).unwrap();
+        for v in s
+            .batch(
+                &(0..200)
+                    .map(|i| (f64::from(i) * 0.3).sin() * 10.0)
+                    .collect::<Vec<_>>(),
+            )
+            .into_iter()
+            .flatten()
+        {
+            assert!((0.0..=1.0).contains(&v));
+        }
+    }
+
+    #[test]
+    fn ignores_non_finite() {
+        let mut s = RollingMinMaxScaler::new(4).unwrap();
+        let ready = s
+            .batch(&[1.0, 2.0, 3.0, 4.0])
+            .into_iter()
+            .flatten()
+            .last()
+            .unwrap();
+        assert_eq!(s.update(f64::NAN), Some(ready));
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut s = RollingMinMaxScaler::new(4).unwrap();
+        s.batch(&[1.0, 2.0, 3.0, 4.0]);
+        assert!(s.is_ready());
+        s.reset();
+        assert!(!s.is_ready());
+        assert_eq!(s.value(), None);
+        assert_eq!(s.update(1.0), None);
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let xs: Vec<f64> = (0..120)
+            .map(|i| (f64::from(i) * 0.25).sin() * 9.0)
+            .collect();
+        let batch = RollingMinMaxScaler::new(14).unwrap().batch(&xs);
+        let mut b = RollingMinMaxScaler::new(14).unwrap();
+        let streamed: Vec<_> = xs.iter().map(|x| b.update(*x)).collect();
+        assert_eq!(batch, streamed);
+    }
+}
@@ -0,0 +1,191 @@
+//! Rolling Percentile Rank of the latest value within its trailing window.
+
+use std::collections::VecDeque;
+
+use crate::error::{Error, Result};
+use crate::traits::Indicator;
+
+/// Percentile rank of the most-recent value within the last `period` values,
+/// in `[0, 100]`.
+///
+/// ```text
+/// rank = 100 · (#below + 0.5 · #equal) / period
+/// ```
+///
+/// where `#below` counts window values strictly less than the current value and
+/// `#equal` counts those equal to it (including the current value itself). This
+/// is the "mean" method of `percentileofscore`: ties are split symmetrically,
+/// so a flat window scores exactly `50`, the strict window maximum scores just
+/// under `100`, and the strict minimum just over `0`.
+///
+/// Percentile rank turns any series into a bounded, self-normalising oscillator:
+/// "where does today sit relative to its own recent history" — high readings
+/// mark stretched extremes, mid readings mark the typical range. It is the
+/// scale-free cousin of the z-score that makes no distributional assumption.
+///
+/// Each `update` is O(period): one linear pass tallies the comparisons.
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Indicator, RollingPercentileRank};
+///
+/// let mut indicator = RollingPercentileRank::new(20).unwrap();
+/// let mut last = None;
+/// for i in 0..40 {
+///     last = indicator.update(100.0 + f64::from(i));
+/// }
+/// // A strictly rising series puts the newest value near the top.
+/// assert!(last.unwrap() > 90.0);
+/// ```
+#[derive(Debug, Clone)]
+pub struct RollingPercentileRank {
+    period: usize,
+    window: VecDeque<f64>,
+}
+
+impl RollingPercentileRank {
+    /// Construct a new rolling percentile rank with the given period.
+    ///
+    /// # Errors
+    /// Returns [`Error::PeriodZero`] if `period == 0`.
+    pub fn new(period: usize) -> Result<Self> {
+        if period == 0 {
+            return Err(Error::PeriodZero);
+        }
+        Ok(Self {
+            period,
+            window: VecDeque::with_capacity(period),
+        })
+    }
+
+    /// Configured period.
+    pub const fn period(&self) -> usize {
+        self.period
+    }
+}
+
+impl Indicator for RollingPercentileRank {
+    type Input = f64;
+    type Output = f64;
+
+    fn update(&mut self, value: f64) -> Option<f64> {
+        if self.window.len() == self.period {
+            self.window.pop_front();
+        }
+        self.window.push_back(value);
+        if self.window.len() < self.period {
+            return None;
+        }
+        let mut below = 0_usize;
+        let mut equal = 0_usize;
+        for &x in &self.window {
+            if x < value {
+                below += 1;
+            } else if x == value {
+                equal += 1;
+            }
+        }
+        let score = (below as f64 + 0.5 * equal as f64) / self.period as f64 * 100.0;
+        Some(score)
+    }
+
+    fn reset(&mut self) {
+        self.window.clear();
+    }
+
+    fn warmup_period(&self) -> usize {
+        self.period
+    }
+
+    fn is_ready(&self) -> bool {
+        self.window.len() == self.period
+    }
+
+    fn name(&self) -> &'static str {
+        "RollingPercentileRank"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    #[test]
+    fn rejects_zero_period() {
+        assert!(matches!(
+            RollingPercentileRank::new(0),
+            Err(Error::PeriodZero)
+        ));
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let pr = RollingPercentileRank::new(14).unwrap();
+        assert_eq!(pr.period(), 14);
+        assert_eq!(pr.warmup_period(), 14);
+        assert_eq!(pr.name(), "RollingPercentileRank");
+        assert!(!pr.is_ready());
+    }
+
+    #[test]
+    fn flat_window_scores_fifty() {
+        // All values equal: #below = 0, #equal = period → 0.5 → 50.
+        let mut pr = RollingPercentileRank::new(10).unwrap();
+        for v in pr.batch(&[7.0; 20]).into_iter().flatten() {
+            assert_relative_eq!(v, 50.0, epsilon = 1e-12);
+        }
+    }
+
+    #[test]
+    fn current_is_strict_maximum() {
+        // Window [1,2,3,4,5], current = 5: #below = 4, #equal = 1.
+        // (4 + 0.5) / 5 * 100 = 90.
+        let mut pr = RollingPercentileRank::new(5).unwrap();
+        let out = pr.batch(&[1.0, 2.0, 3.0, 4.0, 5.0]);
+        assert_relative_eq!(out[4].unwrap(), 90.0, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn current_is_strict_minimum() {
+        // Window [5,4,3,2,1], current = 1: #below = 0, #equal = 1.
+        // (0 + 0.5) / 5 * 100 = 10.
+        let mut pr = RollingPercentileRank::new(5).unwrap();
+        let out = pr.batch(&[5.0, 4.0, 3.0, 2.0, 1.0]);
+        assert_relative_eq!(out[4].unwrap(), 10.0, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn output_within_bounds() {
+        let mut pr = RollingPercentileRank::new(20).unwrap();
+        let prices: Vec<f64> = (1..=200)
+            .map(|i| 100.0 + (f64::from(i) * 0.3).sin() * 12.0)
+            .collect();
+        for v in pr.batch(&prices).into_iter().flatten() {
+            assert!((0.0..=100.0).contains(&v), "out of bounds: {v}");
+        }
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut pr = RollingPercentileRank::new(5).unwrap();
+        pr.batch(&[1.0, 2.0, 3.0, 4.0, 5.0]);
+        assert!(pr.is_ready());
+        pr.reset();
+        assert!(!pr.is_ready());
+        assert_eq!(pr.update(1.0), None);
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let prices: Vec<f64> = (0..60)
+            .map(|i| 100.0 + (f64::from(i) * 0.3).sin() * 5.0)
+            .collect();
+        let batch = RollingPercentileRank::new(14).unwrap().batch(&prices);
+        let mut b = RollingPercentileRank::new(14).unwrap();
+        let streamed: Vec<_> = prices.iter().map(|p| b.update(*p)).collect();
+        assert_eq!(batch, streamed);
+    }
+}
@@ -0,0 +1,230 @@
+//! Rolling Quantile over a trailing window.
+
+use std::collections::VecDeque;
+
+use crate::error::{Error, Result};
+use crate::traits::Indicator;
+
+/// The `quantile`-th quantile of the last `period` values, with linear
+/// interpolation between order statistics.
+///
+/// ```text
+/// h        = (period − 1) · quantile
+/// lower    = ⌊h⌋
+/// result   = sorted[lower] + (h − lower) · (sorted[lower + 1] − sorted[lower])
+/// ```
+///
+/// This is the type-7 / NumPy-default `quantile` definition: `quantile = 0.0`
+/// returns the window minimum, `0.5` the median, `1.0` the maximum, and
+/// fractional values interpolate linearly between the bracketing order
+/// statistics. Rolling quantiles are the building block for distribution-aware
+/// thresholds — a price sitting above its rolling 90th-percentile, a volatility
+/// regime split at the 25th/75th percentiles, robust band edges that ignore the
+/// tails.
+///
+/// Each `update` is O(period log period): the window is copied into a scratch
+/// buffer and sorted with total ordering (NaN-safe).
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Indicator, RollingQuantile};
+///
+/// // Rolling median of the last 5 values.
+/// let mut indicator = RollingQuantile::new(5, 0.5).unwrap();
+/// let out = indicator.update(1.0);
+/// assert!(out.is_none()); // warming up
+/// ```
+#[derive(Debug, Clone)]
+pub struct RollingQuantile {
+    period: usize,
+    quantile: f64,
+    window: VecDeque<f64>,
+    /// Reusable scratch buffer to avoid allocating per `update`.
+    scratch: Vec<f64>,
+}
+
+impl RollingQuantile {
+    /// Construct a new rolling quantile.
+    ///
+    /// `quantile` selects the order statistic in `[0.0, 1.0]`.
+    ///
+    /// # Errors
+    /// Returns [`Error::PeriodZero`] if `period == 0`, or
+    /// [`Error::InvalidParameter`] if `quantile` is not a finite value in
+    /// `[0.0, 1.0]`.
+    pub fn new(period: usize, quantile: f64) -> Result<Self> {
+        if period == 0 {
+            return Err(Error::PeriodZero);
+        }
+        if !quantile.is_finite() || !(0.0..=1.0).contains(&quantile) {
+            return Err(Error::InvalidParameter {
+                message: "rolling quantile must be a finite value in [0.0, 1.0]",
+            });
+        }
+        Ok(Self {
+            period,
+            quantile,
+            window: VecDeque::with_capacity(period),
+            scratch: Vec::with_capacity(period),
+        })
+    }
+
+    /// Configured period.
+    pub const fn period(&self) -> usize {
+        self.period
+    }
+
+    /// Configured quantile in `[0.0, 1.0]`.
+    pub const fn quantile(&self) -> f64 {
+        self.quantile
+    }
+}
+
+/// Linearly-interpolated quantile of a sorted, non-empty slice (type-7).
+pub(crate) fn quantile_sorted(sorted: &[f64], quantile: f64) -> f64 {
+    let n = sorted.len();
+    if n == 1 {
+        return sorted[0];
+    }
+    let h = (n - 1) as f64 * quantile;
+    let lower = h.floor();
+    let idx = lower as usize;
+    // `idx <= n - 1`: when `quantile == 1.0`, `h == n - 1` and `idx == n - 1`,
+    // so the interpolation neighbour would be out of bounds — return the top.
+    if idx >= n - 1 {
+        return sorted[n - 1];
+    }
+    let frac = h - lower;
+    sorted[idx] + frac * (sorted[idx + 1] - sorted[idx])
+}
+
+impl Indicator for RollingQuantile {
+    type Input = f64;
+    type Output = f64;
+
+    fn update(&mut self, value: f64) -> Option<f64> {
+        if self.window.len() == self.period {
+            self.window.pop_front();
+        }
+        self.window.push_back(value);
+        if self.window.len() < self.period {
+            return None;
+        }
+        self.scratch.clear();
+        self.scratch.extend(self.window.iter().copied());
+        self.scratch.sort_by(f64::total_cmp);
+        Some(quantile_sorted(&self.scratch, self.quantile))
+    }
+
+    fn reset(&mut self) {
+        self.window.clear();
+        self.scratch.clear();
+    }
+
+    fn warmup_period(&self) -> usize {
+        self.period
+    }
+
+    fn is_ready(&self) -> bool {
+        self.window.len() == self.period
+    }
+
+    fn name(&self) -> &'static str {
+        "RollingQuantile"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+    use approx::assert_relative_eq;
+
+    #[test]
+    fn rejects_zero_period() {
+        assert!(matches!(
+            RollingQuantile::new(0, 0.5),
+            Err(Error::PeriodZero)
+        ));
+    }
+
+    #[test]
+    fn rejects_out_of_range_quantile() {
+        assert!(matches!(
+            RollingQuantile::new(5, -0.1),
+            Err(Error::InvalidParameter { .. })
+        ));
+        assert!(matches!(
+            RollingQuantile::new(5, 1.1),
+            Err(Error::InvalidParameter { .. })
+        ));
+        assert!(matches!(
+            RollingQuantile::new(5, f64::NAN),
+            Err(Error::InvalidParameter { .. })
+        ));
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let q = RollingQuantile::new(14, 0.25).unwrap();
+        assert_eq!(q.period(), 14);
+        assert_relative_eq!(q.quantile(), 0.25, epsilon = 1e-12);
+        assert_eq!(q.warmup_period(), 14);
+        assert_eq!(q.name(), "RollingQuantile");
+        assert!(!q.is_ready());
+    }
+
+    #[test]
+    fn median_of_window() {
+        // Window [5, 1, 3, 2, 4] sorted [1,2,3,4,5] → median 3.
+        let mut q = RollingQuantile::new(5, 0.5).unwrap();
+        let out = q.batch(&[5.0, 1.0, 3.0, 2.0, 4.0]);
+        assert_relative_eq!(out[4].unwrap(), 3.0, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn min_and_max_quantiles() {
+        let prices = [5.0, 1.0, 3.0, 2.0, 4.0];
+        let lo = RollingQuantile::new(5, 0.0).unwrap().batch(&prices)[4].unwrap();
+        let hi = RollingQuantile::new(5, 1.0).unwrap().batch(&prices)[4].unwrap();
+        assert_relative_eq!(lo, 1.0, epsilon = 1e-12);
+        assert_relative_eq!(hi, 5.0, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn interpolated_quantile() {
+        // sorted [10,20,30,40]: q=0.25 → h=(4-1)*0.25=0.75 → 10 + 0.75*(20-10)=17.5.
+        let mut q = RollingQuantile::new(4, 0.25).unwrap();
+        let out = q.batch(&[40.0, 30.0, 20.0, 10.0]);
+        assert_relative_eq!(out[3].unwrap(), 17.5, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn single_period_returns_value() {
+        // period 1: window holds one value; quantile of a singleton is itself.
+        let mut q = RollingQuantile::new(1, 0.3).unwrap();
+        assert_relative_eq!(q.update(7.0).unwrap(), 7.0, epsilon = 1e-12);
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut q = RollingQuantile::new(5, 0.5).unwrap();
+        q.batch(&[1.0, 2.0, 3.0, 4.0, 5.0]);
+        assert!(q.is_ready());
+        q.reset();
+        assert!(!q.is_ready());
+        assert_eq!(q.update(1.0), None);
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let prices: Vec<f64> = (0..60)
+            .map(|i| 100.0 + (f64::from(i) * 0.3).sin() * 5.0)
+            .collect();
+        let batch = RollingQuantile::new(14, 0.75).unwrap().batch(&prices);
+        let mut b = RollingQuantile::new(14, 0.75).unwrap();
+        let streamed: Vec<_> = prices.iter().map(|p| b.update(*p)).collect();
+        assert_eq!(batch, streamed);
+    }
+}
@@ -25,13 +25,24 @@ use crate::traits::Indicator;
 #[derive(Debug, Clone)]
 pub struct Rsi {
    period: usize,
-    prev_close: Option<f64>,
+    /// `period - 1` as `f64`, precomputed for the Wilder smoothing step.
+    n_minus_1: f64,
+    /// `1 / period`, precomputed so the per-tick smoothing multiplies instead of
+    /// divides (a reciprocal is hoisted out of the hot path).
+    inv_period: f64,
+    /// Previous close, valid once `has_prev` is set. Bare `f64` + flag instead of
+    /// `Option<f64>` to avoid an enum-tag read on every tick.
+    prev_close: f64,
+    has_prev: bool,
    // Wilder seeds with the simple average of the first `period` gains/losses,
    // then transitions to recursive smoothing.
    seed_buf_gains: Vec<f64>,
    seed_buf_losses: Vec<f64>,
-    avg_gain: Option<f64>,
-    avg_loss: Option<f64>,
+    /// Smoothed average gain / loss, valid once `avgs_seeded` is set. Bare `f64`s
+    /// + flag so the hot recurrence avoids reading two `Option<f64>` tags per tick.
+    avg_gain: f64,
+    avg_loss: f64,
+    avgs_seeded: bool,
    last_value: Option<f64>,
 }

@@ -47,11 +58,15 @@ impl Rsi {
        }
        Ok(Self {
            period,
-            prev_close: None,
+            n_minus_1: (period - 1) as f64,
+            inv_period: 1.0 / period as f64,
+            prev_close: 0.0,
+            has_prev: false,
            seed_buf_gains: Vec::with_capacity(period),
            seed_buf_losses: Vec::with_capacity(period),
-            avg_gain: None,
-            avg_loss: None,
+            avg_gain: 0.0,
+            avg_loss: 0.0,
+            avgs_seeded: false,
            last_value: None,
        })
    }
@@ -66,17 +81,87 @@ impl Rsi {
        self.last_value
    }

+    /// Vectorized batch returning one `f64` per input (`NaN` during warmup).
+    ///
+    /// Shadows the generic [`BatchNanExt::batch_nan`](crate::BatchNanExt) blanket
+    /// default. RSI is a recursive (IIR) filter — Wilder smoothing — so it cannot
+    /// be SIMD-vectorized any more than the C peers manage; the win is purely in
+    /// stripping per-tick overhead. For a fresh indicator over an all-finite slice
+    /// long enough to seed (`n > period`) it runs the seed once and then the bare
+    /// smoothing recurrence in a tight loop with no per-tick `is_finite`/`has_prev`/
+    /// `avgs_seeded` branch and no `Option`, using the identical division at the
+    /// seed and `mul_add`/`rsi_from_avgs` afterwards — so it is *bit-for-bit* equal
+    /// to replaying `update`. Shorter or non-fresh/non-finite inputs defer to the
+    /// exact `update` replay.
+    pub fn batch_nan(&mut self, inputs: &[f64]) -> Vec<f64> {
+        let p = self.period;
+        let n = inputs.len();
+        if self.has_prev
+            || self.avgs_seeded
+            || !self.seed_buf_gains.is_empty()
+            || n <= p
+            || !inputs.iter().all(|x| x.is_finite())
+        {
+            return inputs
+                .iter()
+                .map(|&x| self.update(x).unwrap_or(f64::NAN))
+                .collect();
+        }
+
+        // Warmup `[0, p)` is `NaN`; outputs from index `p` on are pushed once each.
+        let mut out = vec![f64::NAN; p];
+        out.reserve(n - p);
+        // Seed from the first `period` diffs (inputs[1..=p]); index 0 only sets the
+        // baseline. Retain the seed gains/losses exactly as `update` leaves them.
+        let mut prev = inputs[0];
+        let (mut sum_gain, mut sum_loss) = (0.0_f64, 0.0_f64);
+        for &x in &inputs[1..=p] {
+            let diff = x - prev;
+            prev = x;
+            let gain = if diff > 0.0 { diff } else { 0.0 };
+            let loss = if diff < 0.0 { -diff } else { 0.0 };
+            self.seed_buf_gains.push(gain);
+            self.seed_buf_losses.push(loss);
+            sum_gain += gain;
+            sum_loss += loss;
+        }
+        let p_f64 = p as f64;
+        let mut ag = sum_gain / p_f64;
+        let mut al = sum_loss / p_f64;
+        out.push(Self::rsi_from_avgs(ag, al));
+
+        // Steady state: Wilder smoothing, reciprocal hoisted, one `rsi_from_avgs`.
+        for &x in &inputs[p + 1..] {
+            let diff = x - prev;
+            prev = x;
+            let gain = if diff > 0.0 { diff } else { 0.0 };
+            let loss = if diff < 0.0 { -diff } else { 0.0 };
+            ag = ag.mul_add(self.n_minus_1, gain) * self.inv_period;
+            al = al.mul_add(self.n_minus_1, loss) * self.inv_period;
+            out.push(Self::rsi_from_avgs(ag, al));
+        }
+
+        // Leave state where a full `update` replay would.
+        self.prev_close = prev;
+        self.has_prev = true;
+        self.avg_gain = ag;
+        self.avg_loss = al;
+        self.avgs_seeded = true;
+        self.last_value = Some(out[n - 1]);
+        out
+    }
+
    fn rsi_from_avgs(avg_gain: f64, avg_loss: f64) -> f64 {
-        if avg_loss == 0.0 {
-            if avg_gain == 0.0 {
-                // No movement at all -> RSI undefined; standard convention returns 50.
-                50.0
-            } else {
-                100.0
-            }
+        // Algebraically `100 - 100/(1 + ag/al)` collapses to `100·ag/(ag+al)`,
+        // which needs a single division instead of two and removes the separate
+        // `rs` step. Edge cases stay exact: `al == 0, ag > 0` gives `100·ag/ag =
+        // 100`; `ag == 0, al > 0` gives `0`; both zero (no movement) is the
+        // undefined case and returns the neutral 50.
+        let denom = avg_gain + avg_loss;
+        if denom == 0.0 {
+            50.0
        } else {
-            let rs = avg_gain / avg_loss;
-            100.0 - 100.0 / (1.0 + rs)
+            100.0 * avg_gain / denom
        }
    }
 }
@@ -90,22 +175,25 @@ impl Indicator for Rsi {
            return self.last_value;
        }

-        let Some(prev) = self.prev_close else {
-            self.prev_close = Some(input);
+        if !self.has_prev {
+            self.prev_close = input;
+            self.has_prev = true;
            return None;
-        };
-        self.prev_close = Some(input);
+        }
+        let prev = self.prev_close;
+        self.prev_close = input;

        let diff = input - prev;
        let gain = if diff > 0.0 { diff } else { 0.0 };
        let loss = if diff < 0.0 { -diff } else { 0.0 };

-        if let (Some(ag), Some(al)) = (self.avg_gain, self.avg_loss) {
-            let n = self.period as f64;
-            let new_ag = (ag * (n - 1.0) + gain) / n;
-            let new_al = (al * (n - 1.0) + loss) / n;
-            self.avg_gain = Some(new_ag);
-            self.avg_loss = Some(new_al);
+        if self.avgs_seeded {
+            // Wilder smoothing `(prev·(n-1) + x) / n` with the reciprocal hoisted:
+            // a fused multiply-add then a multiply by `1/n`, no per-tick division.
+            let new_ag = self.avg_gain.mul_add(self.n_minus_1, gain) * self.inv_period;
+            let new_al = self.avg_loss.mul_add(self.n_minus_1, loss) * self.inv_period;
+            self.avg_gain = new_ag;
+            self.avg_loss = new_al;
            let v = Self::rsi_from_avgs(new_ag, new_al);
            self.last_value = Some(v);
            return Some(v);
@@ -116,8 +204,9 @@ impl Indicator for Rsi {
        if self.seed_buf_gains.len() == self.period {
            let ag = self.seed_buf_gains.iter().sum::<f64>() / self.period as f64;
            let al = self.seed_buf_losses.iter().sum::<f64>() / self.period as f64;
-            self.avg_gain = Some(ag);
-            self.avg_loss = Some(al);
+            self.avg_gain = ag;
+            self.avg_loss = al;
+            self.avgs_seeded = true;
            let v = Self::rsi_from_avgs(ag, al);
            self.last_value = Some(v);
            return Some(v);
@@ -126,11 +215,13 @@ impl Indicator for Rsi {
    }

    fn reset(&mut self) {
-        self.prev_close = None;
+        self.prev_close = 0.0;
+        self.has_prev = false;
        self.seed_buf_gains.clear();
        self.seed_buf_losses.clear();
-        self.avg_gain = None;
-        self.avg_loss = None;
+        self.avg_gain = 0.0;
+        self.avg_loss = 0.0;
+        self.avgs_seeded = false;
        self.last_value = None;
    }

@@ -355,6 +446,65 @@ mod tests {
        assert_eq!(rsi.value(), before);
    }

+    fn bits_eq(a: &[f64], b: &[f64]) -> bool {
+        a.len() == b.len()
+            && a.iter()
+                .zip(b)
+                .all(|(x, y)| x == y || (x.is_nan() && y.is_nan()))
+    }
+
+    fn rsi_replay(period: usize, series: &[f64]) -> Vec<f64> {
+        let mut r = Rsi::new(period).unwrap();
+        series
+            .iter()
+            .map(|&x| r.update(x).unwrap_or(f64::NAN))
+            .collect()
+    }
+
+    #[test]
+    fn batch_nan_fast_path_is_bit_identical() {
+        let series: Vec<f64> = (0..300)
+            .map(|i| (f64::from(i) * 0.3).sin() * 5.0 + f64::from(i) * 0.1 + 100.0)
+            .collect();
+        let mut rsi = Rsi::new(14).unwrap();
+        let got = rsi.batch_nan(&series);
+        assert!(bits_eq(&got, &rsi_replay(14, &series)));
+        let mut ref_rsi = Rsi::new(14).unwrap();
+        for &x in &series {
+            ref_rsi.update(x);
+        }
+        assert_eq!(rsi.update(123.0), ref_rsi.update(123.0));
+    }
+
+    #[test]
+    fn batch_nan_falls_back_on_non_finite() {
+        let series = [10.0, 11.0, 9.0, f64::NAN, 12.0, 13.0, 8.0];
+        let mut rsi = Rsi::new(3).unwrap();
+        assert!(bits_eq(&rsi.batch_nan(&series), &rsi_replay(3, &series)));
+    }
+
+    #[test]
+    fn batch_nan_falls_back_when_not_fresh() {
+        let mut rsi = Rsi::new(3).unwrap();
+        rsi.update(50.0);
+        let series = [51.0, 49.0, 52.0, 53.0, 50.0];
+        let mut ref_rsi = Rsi::new(3).unwrap();
+        ref_rsi.update(50.0);
+        let want: Vec<f64> = series
+            .iter()
+            .map(|&x| ref_rsi.update(x).unwrap_or(f64::NAN))
+            .collect();
+        assert!(bits_eq(&rsi.batch_nan(&series), &want));
+    }
+
+    #[test]
+    fn batch_nan_too_short_to_seed_falls_back() {
+        // n <= period: routed to the exact replay (cannot seed yet).
+        let series = [10.0, 11.0, 12.0];
+        let mut rsi = Rsi::new(3).unwrap();
+        assert!(bits_eq(&rsi.batch_nan(&series), &rsi_replay(3, &series)));
+    }
+
    proptest::proptest! {
        #![proptest_config(proptest::test_runner::Config::with_cases(48))]
        #[test]
--- a/Show More
+++ b/Show More