feat: add Market Breadth family with CrossSection input (#153)

## What Adds a new indicator input type and family for **market-breadth** analysis — indicators that aggregate the state of an entire universe of symbols at each tick, rather than a single instrument's price. This is the last open input-type on the expansion roadmap (S10) and unblocks the remaining breadth indicators (McClellan, TRIN, High-Low Index, ...). ## Core - **`CrossSection` input type** (`crates/wickra-core/src/cross_section.rs`) — one tick carrying the per-symbol state of the whole universe as a `Vec<Member>` + `timestamp`. Each `Member` precomputes a signed `change` (sign classifies advancing / declining / unchanged), a `volume`, and `new_high` / `new_low` extreme flags, so the breadth indicators stay stateless per tick. Both `Member` and `CrossSection` are `#[non_exhaustive]` for additive field growth. `CrossSection::new` validates the universe (non-empty, finite changes, finite non-negative volumes); `new_unchecked` skips validation for hot paths. `advancers()` / `decliners()` count by sign. - **`Error::InvalidCrossSection`** variant for the validation failures. - **`AdvanceDecline`** (`advance_decline.rs`) — the Advance/Decline Line: the running cumulative sum of net advancing-minus-declining issues. `Input = CrossSection`, `Output = f64`, ready after the first tick. - New **"Market Breadth"** `FAMILIES` group; indicator count **314 → 315**, family count nineteen → twenty. ## Bindings All custom (CrossSection is non-scalar, so no macros apply). The universe crosses each boundary as parallel arrays (`change`, `volume`, `new_high`, `new_low`): - **Python / Node** expose `update` + `batch` (one array group per tick). Node satisfies the completeness contract (`update`/`batch`/`reset`/`isReady`/`warmupPeriod`). - **WASM** exposes only `update` (the universe is ragged across ticks, matching the other multi-input wasm indicators) with numeric high/low flags. - Python `map_err` gains the new error arm; `__init__.py` gets a `# Market Breadth` section in both the import and `__all__` blocks. `index.d.ts` / `index.js` regenerated. ## Tests / Fuzz - Dedicated **streaming-vs-batch + reference-value + ragged-rejection** tests in Python (`test_new_indicators.py`) and Node (`indicators.test.js`) — kept out of the scalar/candle parametrize lists. - Rust unit tests cover every reject branch (empty / non-finite change / negative & non-finite volume) and every indicator branch. - New fuzz target `indicator_update_crosssection` drives `AdvanceDecline` over bounded ragged universes built with `new_unchecked`. ## Verify - `cargo fmt --all` clean - `cargo test -p wickra-core --lib` → 2593 passed; `--doc` → 298 passed - `cargo clippy --workspace --all-targets --all-features -- -D warnings` clean - `cd bindings/node && npm run build && npm test` → 398 passed - `maturin develop --release` + `pytest bindings/python/tests` → all passed - counter check: mod-count 315 == lib-block 315
2026-06-03 04:11:10 +02:00
parent 72ec65bbde
commit 53941b7b07
18 changed files with 881 additions and 66 deletions
@@ -0,0 +1,226 @@
+//! Cross-section value type: a market-breadth snapshot across a whole universe.
+//!
+//! A [`CrossSection`] is a single tick that carries the per-symbol state of
+//! *every* symbol in a universe at one point in time. It is the non-OHLCV input
+//! consumed by the market-breadth indicator family (advance/decline, `McClellan`,
+//! the TRIN / Arms index, the high-low index, ...), each of which aggregates the
+//! whole cross-section into a single breadth reading. This is the same
+//! one-rich-type-per-family pattern as [`DerivativesTick`] and [`OrderBook`].
+//!
+//! Each [`Member`] precomputes the per-symbol signals the breadth indicators
+//! need — a signed price `change` (whose sign classifies the symbol as
+//! advancing, declining or unchanged), the period `volume`, and the
+//! `new_high` / `new_low` extreme flags — so the indicators stay stateless per
+//! tick and never have to track per-symbol history.
+//!
+//! [`DerivativesTick`]: crate::DerivativesTick
+//! [`OrderBook`]: crate::OrderBook
+
+use crate::error::{Error, Result};
+
+/// One symbol's contribution to a [`CrossSection`] tick.
+///
+/// Field invariants enforced by [`CrossSection::new`] when the member is placed
+/// into a tick:
+///
+/// - `change` is finite (its sign classifies the symbol — positive is
+///   advancing, negative is declining, zero is unchanged).
+/// - `volume` is finite and non-negative.
+///
+/// `new_high` / `new_low` are caller-supplied flags marking whether the symbol
+/// printed a new period extreme; they carry no numeric invariant.
+#[non_exhaustive]
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub struct Member {
+    /// Price change versus the previous close. Sign classifies the symbol:
+    /// positive is advancing, negative is declining, zero is unchanged.
+    pub change: f64,
+    /// Period volume for the symbol (finite, non-negative).
+    pub volume: f64,
+    /// Whether the symbol printed a new period high.
+    pub new_high: bool,
+    /// Whether the symbol printed a new period low.
+    pub new_low: bool,
+}
+
+impl Member {
+    /// Assemble a cross-section member.
+    ///
+    /// The field invariants documented on [`Member`] are validated centrally by
+    /// [`CrossSection::new`] when the member is placed into a tick; this
+    /// constructor only assembles the value so the `#[non_exhaustive]` struct can
+    /// be built from outside the crate.
+    #[must_use]
+    pub const fn new(change: f64, volume: f64, new_high: bool, new_low: bool) -> Self {
+        Self {
+            change,
+            volume,
+            new_high,
+            new_low,
+        }
+    }
+}
+
+/// A market-breadth cross-section: the per-symbol state of an entire universe at
+/// a single point in time.
+///
+/// Invariants enforced by [`new`](CrossSection::new):
+///
+/// - `members` is non-empty (a breadth reading needs at least one symbol).
+/// - every member's `change` is finite, and `volume` is finite and non-negative.
+///
+/// `timestamp` is a caller-defined epoch / resolution and is not validated.
+#[non_exhaustive]
+#[derive(Debug, Clone, PartialEq)]
+pub struct CrossSection {
+    /// Per-symbol members of the universe for this tick.
+    pub members: Vec<Member>,
+    /// Tick timestamp (caller-defined epoch / resolution).
+    pub timestamp: i64,
+}
+
+impl CrossSection {
+    /// Construct a cross-section, validating every member invariant.
+    ///
+    /// # Errors
+    ///
+    /// Returns [`Error::InvalidCrossSection`] if `members` is empty, if any
+    /// member has a non-finite `change`, or if any member has a `volume` that is
+    /// not a finite non-negative number.
+    pub fn new(members: Vec<Member>, timestamp: i64) -> Result<Self> {
+        if members.is_empty() {
+            return Err(Error::InvalidCrossSection {
+                message: "cross-section must contain at least one member",
+            });
+        }
+        for member in &members {
+            if !member.change.is_finite() {
+                return Err(Error::InvalidCrossSection {
+                    message: "member change must be finite",
+                });
+            }
+            if !member.volume.is_finite() || member.volume < 0.0 {
+                return Err(Error::InvalidCrossSection {
+                    message: "member volume must be finite and non-negative",
+                });
+            }
+        }
+        Ok(Self { members, timestamp })
+    }
+
+    /// Construct a cross-section without validation. The caller asserts that
+    /// every invariant documented on [`CrossSection`] holds.
+    #[must_use]
+    pub const fn new_unchecked(members: Vec<Member>, timestamp: i64) -> Self {
+        Self { members, timestamp }
+    }
+
+    /// Number of advancing symbols (those with a strictly positive `change`).
+    #[must_use]
+    pub fn advancers(&self) -> usize {
+        self.members.iter().filter(|m| m.change > 0.0).count()
+    }
+
+    /// Number of declining symbols (those with a strictly negative `change`).
+    #[must_use]
+    pub fn decliners(&self) -> usize {
+        self.members.iter().filter(|m| m.change < 0.0).count()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn members() -> Vec<Member> {
+        vec![
+            Member::new(1.5, 100.0, true, false),
+            Member::new(-0.5, 50.0, false, true),
+            Member::new(0.0, 0.0, false, false),
+        ]
+    }
+
+    #[test]
+    fn new_accepts_valid() {
+        let cs = CrossSection::new(members(), 42).unwrap();
+        assert_eq!(cs.members.len(), 3);
+        assert_eq!(cs.timestamp, 42);
+        assert_eq!(cs.members[0].change, 1.5);
+        assert_eq!(cs.members[0].volume, 100.0);
+        assert!(cs.members[0].new_high);
+        assert!(cs.members[1].new_low);
+    }
+
+    #[test]
+    fn member_new_assembles_fields() {
+        let m = Member::new(2.0, 10.0, true, false);
+        assert_eq!(m.change, 2.0);
+        assert_eq!(m.volume, 10.0);
+        assert!(m.new_high);
+        assert!(!m.new_low);
+    }
+
+    #[test]
+    fn new_rejects_empty() {
+        assert!(matches!(
+            CrossSection::new(Vec::new(), 0),
+            Err(Error::InvalidCrossSection { .. })
+        ));
+    }
+
+    #[test]
+    fn new_rejects_non_finite_change() {
+        assert!(matches!(
+            CrossSection::new(vec![Member::new(f64::NAN, 10.0, false, false)], 0),
+            Err(Error::InvalidCrossSection { .. })
+        ));
+        assert!(matches!(
+            CrossSection::new(vec![Member::new(f64::INFINITY, 10.0, false, false)], 0),
+            Err(Error::InvalidCrossSection { .. })
+        ));
+    }
+
+    #[test]
+    fn new_rejects_negative_volume() {
+        assert!(matches!(
+            CrossSection::new(vec![Member::new(1.0, -1.0, false, false)], 0),
+            Err(Error::InvalidCrossSection { .. })
+        ));
+    }
+
+    #[test]
+    fn new_rejects_non_finite_volume() {
+        assert!(matches!(
+            CrossSection::new(vec![Member::new(1.0, f64::NAN, false, false)], 0),
+            Err(Error::InvalidCrossSection { .. })
+        ));
+    }
+
+    #[test]
+    fn new_unchecked_skips_validation() {
+        let cs = CrossSection::new_unchecked(vec![Member::new(f64::NAN, -1.0, false, false)], 7);
+        assert_eq!(cs.members.len(), 1);
+        assert_eq!(cs.timestamp, 7);
+    }
+
+    #[test]
+    fn advancers_and_decliners_count_by_sign() {
+        let cs = CrossSection::new(members(), 0).unwrap();
+        assert_eq!(cs.advancers(), 1);
+        assert_eq!(cs.decliners(), 1);
+    }
+
+    #[test]
+    fn unchanged_members_count_as_neither() {
+        let cs = CrossSection::new(
+            vec![
+                Member::new(0.0, 1.0, false, false),
+                Member::new(0.0, 1.0, false, false),
+            ],
+            0,
+        )
+        .unwrap();
+        assert_eq!(cs.advancers(), 0);
+        assert_eq!(cs.decliners(), 0);
+    }
+}