Commit Graph
2 Commits
Author SHA1 Message Date
kingchencandGitHub 99497eb062 fix(core): reject non-finite input in 16 pairwise indicators (#251)
## Problem

16 of the 24 pairwise indicators (`type Input = (f64, f64)`) accepted non-finite input unchecked. A single NaN/Inf tick produced a NaN reading, contradicting the streaming-robustness guarantee that *a single bad tick cannot silently poison state* (README, `ARCHITECTURE.md`).

The other 8 pairwise indicators (`Alpha`, `InformationRatio`, `KalmanHedgeRatio`, `PairSpreadZScore`, `PairwiseBeta`, `RelativeStrengthAb`, `SpreadBollingerBands`, `TreynorRatio`) already guard finite input and are untouched. Scalar (169 files) and candle (`Candle::new`) inputs were already protected.

## Severity split

- **7 running-sum indicators** \(permanent corruption — NaN entered `Σ` and stayed until `reset()`\): `Beta`, `BetaNeutralSpread`, `Cointegration`, `HasbrouckInformationShare`, `PearsonCorrelation`, `RollingCorrelation`, `RollingCovariance`.
- **9 buffer-recompute indicators** \(transient — NaN cleared once evicted, but still surfaced in the reading\): `DistanceSsd`, `GrangerCausality`, `KendallTau`, `LeadLagCrossCorrelation`, `OuHalfLife`, `SpearmanCorrelation`, `SpreadAr1Coefficient`, `SpreadHurst`, `VarianceRatio`.

## Fix

Add the established finite-input guard (the same pattern `Alpha` already uses) as the first step of `update()`, before any window or sum mutation. Signature unchanged → bindings re-export unchanged, no binding regen needed; core-only.

Each indicator gains a `non_finite_input_returns_none` test that exercises the guard (NaN and Inf, covering both `||` operands) and proves a clean warmup is unaffected by the rejected ticks.

Split into two commits by severity class.

## Verification

- `cargo fmt --all` clean
- `cargo test --workspace --all-features` — 4225 core tests pass (+16 new)
- `cargo clippy --workspace --all-targets --all-features -- -D warnings` clean
2026-06-11 03:01:24 +02:00
kingchencandGitHub 0b85142ad1 feat: cross-asset / pairwise indicators (5 new) (#109)
* feat(core): add PairwiseBeta cross-asset indicator

Rolling OLS slope of one asset's log-returns on another's. Unlike Beta,
which regresses the raw inputs it is fed, PairwiseBeta differences
consecutive prices into log-returns internally -- the conventional way to
measure cross-asset beta, where a beta on price levels would be dominated
by the shared trend.

Two-series Indicator<Input = (f64, f64)>, exposed in Rust, Python, Node
and WASM, with unit/known-value/streaming tests and a pair fuzz target.

* feat(core): add PairSpreadZScore cross-asset indicator

Standardised log-spread ln(a) - beta*ln(b) of a pair, where beta is a
rolling-OLS hedge ratio and the spread is z-scored over its own look-back.
The canonical mean-reversion / statistical-arbitrage entry signal, with
independent beta_period and z_period windows.

Two-series Indicator<Input = (f64, f64)>, exposed in Rust, Python, Node
and WASM, with sign/known-value/streaming tests and a pair fuzz target.

* feat(core): add LeadLagCrossCorrelation cross-asset indicator

Reports the integer offset k in [-max_lag, max_lag] that maximises
|corr(a[t], b[t+k])|, answering which of two assets leads the other and by
how many bars. A positive lag means a leads b. Fully causal: a's window is
held centred while b's window slides across the buffered history, so every
lag is evaluated only against data already seen.

Struct output { lag, correlation }, exposed in Rust, Python, Node and WASM
with lead-detection/streaming tests and a pair fuzz driver.

* feat(core): add Cointegration (Engle-Granger + ADF) indicator

Rolling pairs-trading screen: an OLS hedge ratio of a on b, the spread
(residual) a - (alpha + beta*b), and an augmented Dickey-Fuller t-statistic
on the spread with configurable lags. A strongly negative statistic flags a
mean-reverting, tradeable spread. Includes a small Gaussian-elimination
solver for the augmented regression.

Struct output { hedge_ratio, spread, adf_stat }, exposed in Rust, Python,
Node and WASM with stationarity/hedge-ratio/streaming tests and a pair fuzz
driver.

* feat(core): add RelativeStrengthAB cross-asset indicator

Comparative relative strength of two assets: the ratio line a/b together
with its moving average and its RSI, the classic asset-vs-asset /
asset-vs-index rotation screen. Composes the existing Sma and Rsi over the
ratio; a zero denominator or non-finite price is skipped.

Struct output { ratio, ratio_ma, ratio_rsi }, exposed in Rust, Python, Node
and WASM with flat/rising-ratio/streaming tests and a pair fuzz driver.

* test(cointegration): cover ADF guard branches

The ADF helper's short-series and degrees-of-freedom guards and the
zero-dispersion (perfect AR) path are unreachable through the public
Cointegration API (period >= 2*adf_lags + 4), so exercise them with direct
unit tests on adf_no_constant. The second linear solve cannot be singular
once the coefficient solve on the same matrix has succeeded, so it now uses
expect() instead of a dead error branch.
2026-06-01 13:45:21 +02:00