F11: add SuperTrend, Chandelier Exit, Chande Kroll Stop and ATR Trailing Stop
- Rust core: super_trend.rs (SuperTrend — ATR-banded trailing stop with
flip logic; SuperTrendOutput { value, direction }), chandelier_exit.rs
(Chandelier Exit — ATR stop hung off the window's highest high / lowest
low; ChandelierExitOutput { long_stop, short_stop }),
chande_kroll_stop.rs (Chande Kroll Stop — a two-stage ATR stop;
ChandeKrollStopOutput { stop_long, stop_short }), atr_trailing_stop.rs
(ATR Trailing Stop — a single ratcheting close-based stop). Each with a
full Indicator impl, runnable doctest and reference / property / warmup
/ reset / batch==streaming tests.
- Python: PySuperTrend / PyChandelierExit / PyChandeKrollStop /
PyAtrTrailingStop PyO3 classes (struct outputs as tuples and (n, 2)
arrays) + module registration + .pyi stubs.
- Node: explicit SuperTrendNode / ChandelierExitNode / ChandeKrollStopNode
/ AtrTrailingStopNode with SuperTrendValue / ChandelierExitValue /
ChandeKrollStopValue objects; index.d.ts and index.js updated.
- WASM: WasmSuperTrend / WasmChandelierExit / WasmChandeKrollStop /
WasmAtrTrailingStop.
- Wiki: Indicator-SuperTrend/ChandelierExit/ChandeKrollStop/
AtrTrailingStop.md plus rows in the "Trailing stop" table of
Indicators-Overview.md and entries in Home.md.
- Add clippy.toml with doc-valid-idents for the proper noun "LeBeau".
cargo fmt + clippy (core/wickra/data/wasm/node) clean; 427 core tests,
25 data tests and 61 doctests green.
This commit is contained in:
kingchenc
@@ -124,6 +124,10 @@ Rust / Python / Node examples. They are grouped by family, mirroring the
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- [Indicator-HistoricalVolatility.md](indicators/volatility/Indicator-HistoricalVolatility.md)
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- [Indicator-BollingerBandwidth.md](indicators/volatility/Indicator-BollingerBandwidth.md)
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- [Indicator-PercentB.md](indicators/volatility/Indicator-PercentB.md)
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- [Indicator-SuperTrend.md](indicators/volatility/Indicator-SuperTrend.md)
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- [Indicator-ChandelierExit.md](indicators/volatility/Indicator-ChandelierExit.md)
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- [Indicator-ChandeKrollStop.md](indicators/volatility/Indicator-ChandeKrollStop.md)
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- [Indicator-AtrTrailingStop.md](indicators/volatility/Indicator-AtrTrailingStop.md)
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**Volume** — price moves weighted or confirmed by traded volume.
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@@ -1,6 +1,6 @@
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# Indicators Overview
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Wickra ships 54 indicators, organised in source under the four classical
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Wickra ships 58 indicators, organised in source under the four classical
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families — trend, momentum, volatility, volume — that map directly to the
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directory structure of `crates/wickra-core/src/indicators/`. The same family
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labels are used here, plus a second-level grouping that reflects how the
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@@ -118,10 +118,10 @@ Centered on zero or driven by raw price differences; no fixed cap.
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## Volatility
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Volatility indicators sit in two functional groups: those that draw an
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envelope around price, and those that report a scalar dispersion/range.
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PSAR is a special case — a trailing-stop tracker rather than a width
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measure — that lives in the volatility module by source convention.
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Volatility indicators sit in three functional groups: those that draw an
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envelope around price, those that report a scalar dispersion/range, and a
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set of trailing stops — ATR-driven stop-loss trackers rather than width
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measures — that live in the volatility module by source convention.
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### Envelopes
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@@ -148,6 +148,10 @@ measure — that lives in the volatility module by source convention.
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| Indicator | One-liner | Input | Output | Range | Defaults | Warmup | Deep dive |
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|-----------|-----------|-------|--------|-------|----------|--------|-----------|
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| `Psar` | Wilder's Parabolic Stop-and-Reverse; per-bar stop level that flips sides on price crossing. | `Candle` | `f64` | unbounded (price scale) | `(af_start=0.02, af_step=0.02, af_max=0.20)` (Python) | `2` | [Indicator-Psar.md](indicators/volatility/Indicator-Psar.md) |
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| `SuperTrend` | ATR-banded trailing stop that flips on a close through the band; reports the line and the trend direction. | `Candle` | `(value, direction)` | `value` price scale; `direction` `±1` | `(atr_period=10, multiplier=3.0)` (Python) | `atr_period` | [Indicator-SuperTrend.md](indicators/volatility/Indicator-SuperTrend.md) |
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| `ChandelierExit` | `highest_high − k·ATR` (long stop) and `lowest_low + k·ATR` (short stop). | `Candle` | `(long_stop, short_stop)` | unbounded (price scale) | `(period=22, multiplier=3.0)` (Python) | `period` | [Indicator-ChandelierExit.md](indicators/volatility/Indicator-ChandelierExit.md) |
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| `ChandeKrollStop` | Two-stage ATR stop: an extreme-based stop, then smoothed over a shorter window. | `Candle` | `(stop_long, stop_short)` | unbounded (price scale) | `(atr_period=10, atr_multiplier=1.0, stop_period=9)` (Python) | `atr_period + stop_period − 1` | [Indicator-ChandeKrollStop.md](indicators/volatility/Indicator-ChandeKrollStop.md) |
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| `AtrTrailingStop` | A single line trailing the close by `k·ATR`, ratcheting toward the trend and flipping on a cross. | `Candle` | `f64` | unbounded (price scale) | `(atr_period=14, multiplier=3.0)` (Python) | `atr_period` | [Indicator-AtrTrailingStop.md](indicators/volatility/Indicator-AtrTrailingStop.md) |
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## Volume
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@@ -0,0 +1,170 @@
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# AtrTrailingStop
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> ATR Trailing Stop — a single stop level that trails price by a fixed ATR
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> multiple, ratcheting toward the trend and flipping on a close through it.
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## Quick reference
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| Field | Value |
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|-------|-------|
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| Family | Volatility |
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| Sub-category | Trailing stop |
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| Input type | `Candle` (uses `high`, `low`, `close`) |
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| Output type | `f64` |
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| Output range | unbounded (price scale) |
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| Default parameters | `atr_period = 14`, `multiplier = 3.0` (Python) |
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| Warmup period | `atr_period` |
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| Interpretation | One trailing stop line; price closing through it flips the trade. |
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## Formula
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```
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loss = multiplier · ATR
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stop_t = max(stop_{t−1}, close − loss) while price holds above the stop
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= min(stop_{t−1}, close + loss) while price holds below the stop
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= close − loss on a fresh break above the stop
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= close + loss on a fresh break below the stop
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```
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This is the trailing stop popularised by the "UT Bot": a single line that sits
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`multiplier · ATR` away from the close. While price holds on one side of the
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stop the level only ratchets *toward* price — up in an uptrend, down in a
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downtrend — and never away from it. When a close crosses the stop the level
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snaps to the opposite side of the new close, flipping the trade. Unlike the
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[`ChandelierExit`](Indicator-ChandelierExit.md), it hangs off the close
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itself, not the window's extreme, and reports one line rather than two.
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## Parameters
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- `atr_period` — the ATR lookback (Python default `14`).
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- `multiplier` — the ATR multiple the stop trails by (Python default `3.0`).
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`AtrTrailingStop::classic()` returns the `(14, 3.0)` configuration.
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## Inputs / Outputs
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From `crates/wickra-core/src/indicators/atr_trailing_stop.rs`:
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```rust
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impl Indicator for AtrTrailingStop {
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type Input = Candle;
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type Output = f64;
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// update(&mut self, input: Candle) -> Option<f64>
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}
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```
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`AtrTrailingStop` is a **candle-input** indicator (it reads `high`, `low`,
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`close`). In Python the streaming `update` accepts a 6-tuple or a dict; the
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batch helper takes `high`, `low`, `close` numpy arrays. Node and WASM expose
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`update(high, low, close)` and the matching `batch`.
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## Warmup
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`AtrTrailingStop::classic().warmup_period() == 14`. The first value lands once
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the inner ATR is ready, on input index `atr_period − 1`. That first bar seeds
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the stop below price (a long).
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## Edge cases
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- **Seed bar.** The first emitted stop is `close − loss` — the indicator
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starts on the long side.
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- **Ratchet.** While price holds above the stop it never moves down, and
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while price holds below it never moves up
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(`uptrend_stop_ratchets_up_and_stays_below_price` pins this).
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- **Flat market.** Constant candles hold the stop at a fixed `close − loss`.
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- **Reset.** `ts.reset()` clears the ATR and the carried stop / close.
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## Examples
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### Rust
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```rust
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use wickra::{BatchExt, Candle, Indicator, AtrTrailingStop};
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fn main() -> Result<(), Box<dyn std::error::Error>> {
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let mut ts = AtrTrailingStop::new(5, 3.0)?;
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// Flat market: ATR = 2, loss = 3·2 = 6, stop = 10 - 6 = 4.
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let candles: Vec<Candle> = (0..20)
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.map(|i| Candle::new(10.0, 11.0, 9.0, 10.0, 1.0, i).unwrap())
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.collect();
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let out = ts.batch(&candles);
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println!("{:?}", out.last().unwrap());
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Ok(())
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}
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```
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Output:
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```
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Some(4.0)
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```
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On a flat market the seeded long stop holds at `close − loss = 10 − 6 = 4`.
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This matches the `reference_values_flat_market` test in
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`crates/wickra-core/src/indicators/atr_trailing_stop.rs`.
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### Python
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```python
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import numpy as np
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import wickra as ta
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ts = ta.AtrTrailingStop(5, 3.0)
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n = 20
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high = np.full(n, 11.0)
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low = np.full(n, 9.0)
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close = np.full(n, 10.0)
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print(ts.batch(high, low, close)[-1])
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```
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Output:
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```
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4.0
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```
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### Node
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```javascript
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const ta = require('wickra');
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const ts = new ta.AtrTrailingStop(5, 3.0);
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const n = 20;
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const high = Array(n).fill(11), low = Array(n).fill(9), close = Array(n).fill(10);
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const out = ts.batch(high, low, close);
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console.log(out[out.length - 1]);
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```
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Output:
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```
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4
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```
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## Interpretation
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Read it as a stop-and-reverse line: while the stop sits below the close you
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are long and it trails your profit up; the bar a close prints below the stop,
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it flips above the new close and you are short. A larger `multiplier` gives
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the trade more room — fewer flips, wider risk; a smaller one flips sooner.
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## Common pitfalls
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- **Expecting it off the window high.** It trails the *close*, so it can sit
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closer to price than a [`ChandelierExit`](Indicator-ChandelierExit.md).
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- **Feeding it scalar prices.** It needs the full `high`/`low`/`close` bar to
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drive the ATR.
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## References
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The ATR Trailing Stop used by the well-known "UT Bot"; the four-branch ratchet
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here matches the common Sylvain Vervoort formulation.
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## See also
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- [Indicator-SuperTrend.md](Indicator-SuperTrend.md) — an ATR trailing stop
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with band ratcheting and an explicit direction flag.
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- [Indicator-ChandelierExit.md](Indicator-ChandelierExit.md) — an ATR stop hung
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off the window's extreme instead of the close.
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- [Indicator-Atr.md](Indicator-Atr.md) — the volatility measure underneath.
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- [Indicators-Overview.md](../../Indicators-Overview.md) — the full taxonomy.
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@@ -0,0 +1,177 @@
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# ChandeKrollStop
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> Chande Kroll Stop — a two-stage ATR stop: an ATR stop off the recent
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> extreme, then smoothed by taking the most extreme such stop over a
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> shorter window.
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## Quick reference
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| Field | Value |
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|-------|-------|
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| Family | Volatility |
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| Sub-category | Trailing stop |
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| Input type | `Candle` (uses `high`, `low`, `close`) |
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| Output type | `(stop_long, stop_short)` |
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| Output range | unbounded (price scale) |
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| Default parameters | `atr_period = 10`, `atr_multiplier = 1.0`, `stop_period = 9` (Python) |
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| Warmup period | `atr_period + stop_period − 1` |
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| Interpretation | Smoothed long/short stop levels, less prone to single-bar whipsaw. |
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## Formula
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```
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preliminary (window p = atr_period, x = atr_multiplier):
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high_stop = highest_high(p) − x · ATR(p)
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low_stop = lowest_low(p) + x · ATR(p)
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final (window q = stop_period):
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stop_short = highest(high_stop, q)
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stop_long = lowest(low_stop, q)
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```
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Tushar Chande and Stanley Kroll's stop runs in two stages. The first builds a
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preliminary ATR stop off the recent extreme — the same idea as a
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[`ChandelierExit`](Indicator-ChandelierExit.md). The second smooths it: rather
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than use that preliminary stop directly, it takes the *most extreme*
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preliminary stop seen over a shorter window `q`. That second pass keeps a
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single unusually wide bar from yanking the stop around. The classic
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configuration from *The New Technical Trader* is `ATR(10)`, multiplier `1.0`,
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smoothing window `9`.
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## Parameters
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- `atr_period` — window for the preliminary ATR and the highest high / lowest
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low (Python default `10`).
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- `atr_multiplier` — how many ATRs the preliminary stop sits off the extreme
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(default `1.0`).
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- `stop_period` — the smoothing window `q` (default `9`).
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`ChandeKrollStop::classic()` returns the `(10, 1.0, 9)` configuration.
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## Inputs / Outputs
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From `crates/wickra-core/src/indicators/chande_kroll_stop.rs`:
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```rust
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impl Indicator for ChandeKrollStop {
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type Input = Candle;
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type Output = ChandeKrollStopOutput; // { stop_long: f64, stop_short: f64 }
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// update(&mut self, input: Candle) -> Option<ChandeKrollStopOutput>
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}
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```
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`ChandeKrollStop` is a **candle-input** indicator (it reads `high`, `low`,
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`close`). Python's streaming `update` returns a `(stop_long, stop_short)`
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tuple; the batch helper returns an `(n, 2)` array with columns
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`[stop_long, stop_short]`. Node's `update` returns `{ stopLong, stopShort }`
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and `batch` a flat `[l0, s0, l1, s1, …]` array; WASM matches Node.
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## Warmup
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`ChandeKrollStop::classic().warmup_period() == 18` (`atr_period + stop_period −
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1`). The preliminary stop first appears on candle `atr_period`; the smoothing
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window then needs `stop_period` of them.
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## Edge cases
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- **Two-stage warmup.** Nothing is emitted until both the preliminary window
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and the smoothing window have filled.
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- **Flat market.** Constant candles collapse both stages to fixed levels.
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- **Reset.** `cks.reset()` clears the ATR and all four windows.
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## Examples
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### Rust
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```rust
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use wickra::{BatchExt, Candle, Indicator, ChandeKrollStop};
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fn main() -> Result<(), Box<dyn std::error::Error>> {
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let mut cks = ChandeKrollStop::new(5, 1.0, 3)?;
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// Flat market: ATR = 2, HH = 11, LL = 9.
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let candles: Vec<Candle> = (0..20)
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.map(|i| Candle::new(10.0, 11.0, 9.0, 10.0, 1.0, i).unwrap())
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.collect();
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let out = cks.batch(&candles);
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println!("{:?}", out.last().unwrap());
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Ok(())
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}
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```
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Output:
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```
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Some(ChandeKrollStopOutput { stop_long: 11.0, stop_short: 9.0 })
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```
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`high_stop = 11 − 1·2 = 9`, `low_stop = 9 + 1·2 = 11`; the smoothing pass over
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constant values leaves `stop_short = 9` and `stop_long = 11`. This matches the
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`reference_values_flat_market` test in
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`crates/wickra-core/src/indicators/chande_kroll_stop.rs`.
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### Python
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```python
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import numpy as np
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import wickra as ta
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cks = ta.ChandeKrollStop(5, 1.0, 3)
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n = 20
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high = np.full(n, 11.0)
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low = np.full(n, 9.0)
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close = np.full(n, 10.0)
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print(cks.batch(high, low, close)[-1]) # [stop_long, stop_short]
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```
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Output:
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```
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[11. 9.]
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```
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### Node
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```javascript
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const ta = require('wickra');
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const cks = new ta.ChandeKrollStop(5, 1.0, 3);
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const n = 20;
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const high = Array(n).fill(11), low = Array(n).fill(9), close = Array(n).fill(10);
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const out = cks.batch(high, low, close);
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console.log(out.slice(-2)); // [stop_long, stop_short] of the last bar
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```
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Output:
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```
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[ 11, 9 ]
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```
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## Interpretation
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Use `stop_long` to trail a long position and `stop_short` to trail a short.
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Compared with a one-stage [`ChandelierExit`](Indicator-ChandelierExit.md), the
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extra smoothing window makes the Chande Kroll Stop steadier — it will not lurch
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on a single wide-range bar — at the cost of reacting a little slower to a
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genuine trend change.
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## Common pitfalls
|
||||
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- **Forgetting the longer warmup.** Two stacked windows mean `atr_period +
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stop_period − 1` bars before the first value.
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- **Confusing the labels.** `stop_short` is generally the lower level and
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`stop_long` the higher — they bracket recent price, but each only applies to
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its own side.
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## References
|
||||
|
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Tushar Chande and Stanley Kroll's stop, from *The New Technical Trader* (1994);
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the two-stage formulation here matches the common TradingView implementation.
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## See also
|
||||
|
||||
- [Indicator-ChandelierExit.md](Indicator-ChandelierExit.md) — the one-stage
|
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ATR stop this smooths.
|
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- [Indicator-SuperTrend.md](Indicator-SuperTrend.md) — an ATR trailing stop
|
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with explicit flip logic.
|
||||
- [Indicator-Atr.md](Indicator-Atr.md) — the volatility measure underneath.
|
||||
- [Indicators-Overview.md](../../Indicators-Overview.md) — the full taxonomy.
|
||||
@@ -0,0 +1,166 @@
|
||||
# ChandelierExit
|
||||
|
||||
> Chandelier Exit — an ATR trailing stop hung a fixed number of ATRs off
|
||||
> the highest high (for longs) or the lowest low (for shorts) of a window.
|
||||
|
||||
## Quick reference
|
||||
|
||||
| Field | Value |
|
||||
|-------|-------|
|
||||
| Family | Volatility |
|
||||
| Sub-category | Trailing stop |
|
||||
| Input type | `Candle` (uses `high`, `low`, `close`) |
|
||||
| Output type | `(long_stop, short_stop)` |
|
||||
| Output range | unbounded (price scale) |
|
||||
| Default parameters | `period = 22`, `multiplier = 3.0` (Python) |
|
||||
| Warmup period | `period` |
|
||||
| Interpretation | Long/short trailing-stop levels; a close past one exits the trade. |
|
||||
|
||||
## Formula
|
||||
|
||||
```
|
||||
long_stop = highest_high(period) − multiplier · ATR(period)
|
||||
short_stop = lowest_low(period) + multiplier · ATR(period)
|
||||
```
|
||||
|
||||
Chuck LeBeau's Chandelier Exit hangs the stop off the extreme of the lookback
|
||||
window — like a chandelier off a ceiling — a fixed `multiplier · ATR` below the
|
||||
highest high (for a long) or above the lowest low (for a short). Because the
|
||||
extreme only moves favourably while a trend runs, the stop trails price up
|
||||
(or down) and never loosens. A long is exited when price closes below
|
||||
`long_stop`; a short when it closes above `short_stop`. The classic
|
||||
configuration is a `22`-bar window with a `3.0` multiplier.
|
||||
|
||||
## Parameters
|
||||
|
||||
- `period` — the window for both the highest high / lowest low and the ATR
|
||||
(Python default `22`).
|
||||
- `multiplier` — how many ATRs the stop hangs off the extreme (default `3.0`).
|
||||
|
||||
`ChandelierExit::classic()` returns the `(22, 3.0)` configuration.
|
||||
|
||||
## Inputs / Outputs
|
||||
|
||||
From `crates/wickra-core/src/indicators/chandelier_exit.rs`:
|
||||
|
||||
```rust
|
||||
impl Indicator for ChandelierExit {
|
||||
type Input = Candle;
|
||||
type Output = ChandelierExitOutput; // { long_stop: f64, short_stop: f64 }
|
||||
// update(&mut self, input: Candle) -> Option<ChandelierExitOutput>
|
||||
}
|
||||
```
|
||||
|
||||
`ChandelierExit` is a **candle-input** indicator (it reads `high`, `low`,
|
||||
`close`). Python's streaming `update` returns a `(long_stop, short_stop)`
|
||||
tuple; the batch helper returns an `(n, 2)` array with columns
|
||||
`[long_stop, short_stop]`. Node's `update` returns `{ longStop, shortStop }`
|
||||
and `batch` a flat `[l0, s0, l1, s1, …]` array; WASM matches Node.
|
||||
|
||||
## Warmup
|
||||
|
||||
`ChandelierExit::classic().warmup_period() == 22`. The highest-high / lowest-low
|
||||
window and the inner ATR become ready on the same candle — input index
|
||||
`period − 1`.
|
||||
|
||||
## Edge cases
|
||||
|
||||
- **Window bound.** `long_stop` never exceeds the window's highest high, and
|
||||
`short_stop` never drops below its lowest low
|
||||
(`long_stop_below_highest_short_stop_above_lowest` pins this).
|
||||
- **Flat market.** Constant candles give constant `ATR` and equal extremes, so
|
||||
both stops sit a fixed `multiplier · ATR` from the price.
|
||||
- **Reset.** `ce.reset()` clears the ATR and both extreme windows.
|
||||
|
||||
## Examples
|
||||
|
||||
### Rust
|
||||
|
||||
```rust
|
||||
use wickra::{BatchExt, Candle, Indicator, ChandelierExit};
|
||||
|
||||
fn main() -> Result<(), Box<dyn std::error::Error>> {
|
||||
let mut ce = ChandelierExit::new(5, 3.0)?;
|
||||
// Flat market: ATR = 2, HH = 11, LL = 9.
|
||||
let candles: Vec<Candle> = (0..20)
|
||||
.map(|i| Candle::new(10.0, 11.0, 9.0, 10.0, 1.0, i).unwrap())
|
||||
.collect();
|
||||
let out = ce.batch(&candles);
|
||||
println!("{:?}", out.last().unwrap());
|
||||
Ok(())
|
||||
}
|
||||
```
|
||||
|
||||
Output:
|
||||
|
||||
```
|
||||
Some(ChandelierExitOutput { long_stop: 5.0, short_stop: 15.0 })
|
||||
```
|
||||
|
||||
`long_stop = 11 − 3·2 = 5`, `short_stop = 9 + 3·2 = 15`. This matches the
|
||||
`reference_values_flat_market` test in
|
||||
`crates/wickra-core/src/indicators/chandelier_exit.rs`.
|
||||
|
||||
### Python
|
||||
|
||||
```python
|
||||
import numpy as np
|
||||
import wickra as ta
|
||||
|
||||
ce = ta.ChandelierExit(5, 3.0)
|
||||
n = 20
|
||||
high = np.full(n, 11.0)
|
||||
low = np.full(n, 9.0)
|
||||
close = np.full(n, 10.0)
|
||||
print(ce.batch(high, low, close)[-1]) # [long_stop, short_stop]
|
||||
```
|
||||
|
||||
Output:
|
||||
|
||||
```
|
||||
[ 5. 15.]
|
||||
```
|
||||
|
||||
### Node
|
||||
|
||||
```javascript
|
||||
const ta = require('wickra');
|
||||
const ce = new ta.ChandelierExit(5, 3.0);
|
||||
const n = 20;
|
||||
const high = Array(n).fill(11), low = Array(n).fill(9), close = Array(n).fill(10);
|
||||
const out = ce.batch(high, low, close);
|
||||
console.log(out.slice(-2)); // [long_stop, short_stop] of the last bar
|
||||
```
|
||||
|
||||
Output:
|
||||
|
||||
```
|
||||
[ 5, 15 ]
|
||||
```
|
||||
|
||||
## Interpretation
|
||||
|
||||
While long, watch `long_stop`: it climbs as new highs print and never falls,
|
||||
so a close beneath it is a disciplined exit. While short, `short_stop` is the
|
||||
mirror. The `3.0` multiplier is wide enough to ride a trend through normal
|
||||
pullbacks; tightening it exits sooner at the cost of more whipsaws.
|
||||
|
||||
## Common pitfalls
|
||||
|
||||
- **Using the wrong stop for the position.** `long_stop` only applies to
|
||||
longs, `short_stop` only to shorts — they are not a channel.
|
||||
- **Feeding it scalar prices.** It needs the full `high`/`low`/`close` bar.
|
||||
|
||||
## References
|
||||
|
||||
Chuck LeBeau's Chandelier Exit; the highest-high-minus-ATR formulation here
|
||||
matches the standard definition.
|
||||
|
||||
## See also
|
||||
|
||||
- [Indicator-SuperTrend.md](Indicator-SuperTrend.md) — an ATR trailing stop
|
||||
with explicit flip logic and a single line.
|
||||
- [Indicator-ChandeKrollStop.md](Indicator-ChandeKrollStop.md) — a two-stage
|
||||
ATR stop that smooths the preliminary level.
|
||||
- [Indicator-Atr.md](Indicator-Atr.md) — the volatility measure underneath.
|
||||
- [Indicators-Overview.md](../../Indicators-Overview.md) — the full taxonomy.
|
||||
@@ -0,0 +1,174 @@
|
||||
# SuperTrend
|
||||
|
||||
> SuperTrend — an ATR-banded trailing stop that flips sides when price
|
||||
> closes through the band, reporting both the stop level and the trend
|
||||
> direction.
|
||||
|
||||
## Quick reference
|
||||
|
||||
| Field | Value |
|
||||
|-------|-------|
|
||||
| Family | Volatility |
|
||||
| Sub-category | Trailing stop |
|
||||
| Input type | `Candle` (uses `high`, `low`, `close`) |
|
||||
| Output type | `(value, direction)` |
|
||||
| Output range | `value`: unbounded (price scale); `direction`: `−1.0` or `+1.0` |
|
||||
| Default parameters | `atr_period = 10`, `multiplier = 3.0` (Python) |
|
||||
| Warmup period | `atr_period` |
|
||||
| Interpretation | Trend-following stop; a direction flip marks a trend change. |
|
||||
|
||||
## Formula
|
||||
|
||||
```
|
||||
hl2 = (high + low) / 2
|
||||
basic_upper = hl2 + multiplier · ATR
|
||||
basic_lower = hl2 − multiplier · ATR
|
||||
|
||||
final_upper = basic_upper if basic_upper < prev_final_upper or prev_close > prev_final_upper
|
||||
else prev_final_upper
|
||||
final_lower = basic_lower if basic_lower > prev_final_lower or prev_close < prev_final_lower
|
||||
else prev_final_lower
|
||||
|
||||
downtrend: stay down while close <= final_upper, else flip up
|
||||
uptrend: stay up while close >= final_lower, else flip down
|
||||
SuperTrend = final_lower in an uptrend, final_upper in a downtrend
|
||||
```
|
||||
|
||||
The two final bands ratchet — the upper band only moves down, the lower band
|
||||
only moves up — until price closes through the active one. That close flips
|
||||
the trend and hands the trailing-stop role to the opposite band. The result is
|
||||
a single line that sits below price in an uptrend and above it in a downtrend,
|
||||
plus a `direction` flag (`+1.0` / `-1.0`) that names which regime you are in.
|
||||
|
||||
## Parameters
|
||||
|
||||
- `atr_period` — the ATR lookback (Python default `10`).
|
||||
- `multiplier` — how many ATRs wide the bands sit (Python default `3.0`).
|
||||
|
||||
`SuperTrend::classic()` returns Wilder's `(10, 3.0)` configuration.
|
||||
|
||||
## Inputs / Outputs
|
||||
|
||||
From `crates/wickra-core/src/indicators/super_trend.rs`:
|
||||
|
||||
```rust
|
||||
impl Indicator for SuperTrend {
|
||||
type Input = Candle;
|
||||
type Output = SuperTrendOutput; // { value: f64, direction: f64 }
|
||||
// update(&mut self, input: Candle) -> Option<SuperTrendOutput>
|
||||
}
|
||||
```
|
||||
|
||||
`SuperTrend` is a **candle-input** indicator (it reads `high`, `low`, `close`).
|
||||
Python's streaming `update` returns a `(value, direction)` tuple; the batch
|
||||
helper returns an `(n, 2)` array with columns `[value, direction]`. Node's
|
||||
`update` returns `{ value, direction }` and `batch` a flat `[v0, d0, v1, d1, …]`
|
||||
array; WASM matches Node.
|
||||
|
||||
## Warmup
|
||||
|
||||
`SuperTrend::classic().warmup_period() == 10`. The first value lands once the
|
||||
inner ATR is ready, on input index `atr_period − 1`. The first ATR-ready bar
|
||||
seeds the trend as up; the flip logic corrects it within a few bars if the
|
||||
market is actually falling.
|
||||
|
||||
## Edge cases
|
||||
|
||||
- **Seed direction.** The first emitted bar is always `direction = +1.0`; a
|
||||
genuine downtrend flips it within a handful of bars.
|
||||
- **Flat market.** Constant candles give a constant ATR, so both bands and the
|
||||
line are flat and the trend never flips.
|
||||
- **Reset.** `st.reset()` clears the ATR and the carried band state.
|
||||
|
||||
## Examples
|
||||
|
||||
### Rust
|
||||
|
||||
```rust
|
||||
use wickra::{BatchExt, Candle, Indicator, SuperTrend};
|
||||
|
||||
fn main() -> Result<(), Box<dyn std::error::Error>> {
|
||||
let mut st = SuperTrend::new(5, 3.0)?;
|
||||
// Flat market: ATR = 2, hl2 = 10, lower band = 10 - 3·2 = 4.
|
||||
let candles: Vec<Candle> = (0..20)
|
||||
.map(|i| Candle::new(10.0, 11.0, 9.0, 10.0, 1.0, i).unwrap())
|
||||
.collect();
|
||||
let out = st.batch(&candles);
|
||||
println!("{:?}", out.last().unwrap());
|
||||
Ok(())
|
||||
}
|
||||
```
|
||||
|
||||
Output:
|
||||
|
||||
```
|
||||
Some(SuperTrendOutput { value: 4.0, direction: 1.0 })
|
||||
```
|
||||
|
||||
On a flat market the seeded uptrend never flips and the line holds at the
|
||||
lower band, `4.0`.
|
||||
|
||||
### Python
|
||||
|
||||
```python
|
||||
import numpy as np
|
||||
import wickra as ta
|
||||
|
||||
st = ta.SuperTrend(5, 3.0)
|
||||
n = 20
|
||||
high = np.full(n, 11.0)
|
||||
low = np.full(n, 9.0)
|
||||
close = np.full(n, 10.0)
|
||||
print(st.batch(high, low, close)[-1]) # [value, direction]
|
||||
```
|
||||
|
||||
Output:
|
||||
|
||||
```
|
||||
[4. 1.]
|
||||
```
|
||||
|
||||
### Node
|
||||
|
||||
```javascript
|
||||
const ta = require('wickra');
|
||||
const st = new ta.SuperTrend(5, 3.0);
|
||||
const n = 20;
|
||||
const high = Array(n).fill(11), low = Array(n).fill(9), close = Array(n).fill(10);
|
||||
const out = st.batch(high, low, close);
|
||||
console.log(out.slice(-2)); // [value, direction] of the last bar
|
||||
```
|
||||
|
||||
Output:
|
||||
|
||||
```
|
||||
[ 4, 1 ]
|
||||
```
|
||||
|
||||
## Interpretation
|
||||
|
||||
`SuperTrend` is used as a stop-and-reverse system: stay long while
|
||||
`direction == +1` and the line trails below price, flip to short the bar the
|
||||
`direction` turns `-1` and the line jumps above price. A larger `multiplier`
|
||||
widens the bands — fewer whipsaws, later flips; a smaller one flips sooner.
|
||||
The line itself doubles as a concrete stop-loss level.
|
||||
|
||||
## Common pitfalls
|
||||
|
||||
- **Expecting an exact flip bar.** The seed bar is always an uptrend; on
|
||||
genuinely falling data the flip lands a few bars in.
|
||||
- **Reading `value` without `direction`.** The line means "support" in an
|
||||
uptrend and "resistance" in a downtrend — `direction` tells you which.
|
||||
|
||||
## References
|
||||
|
||||
The SuperTrend trailing stop; the final-band ratchet formulation here matches
|
||||
the widely used TradingView / Olivier Seban definition.
|
||||
|
||||
## See also
|
||||
|
||||
- [Indicator-Psar.md](Indicator-Psar.md) — Wilder's parabolic stop-and-reverse.
|
||||
- [Indicator-AtrTrailingStop.md](Indicator-AtrTrailingStop.md) — a plain
|
||||
ATR trailing stop without the band ratchet.
|
||||
- [Indicator-Atr.md](Indicator-Atr.md) — the volatility measure underneath.
|
||||
- [Indicators-Overview.md](../../Indicators-Overview.md) — the full taxonomy.
|
||||
Reference in New Issue
Block a user