## Summary - Dedicated batch fast paths for **EMA, RSI, Bollinger, MACD and ATR** (used by the Python bindings): one allocation filled in a single pass, warmup encoded as `NaN`, no per-element `Option` or input re-validation. Each is **bit-for-bit equal** to replaying `update` — SMA/Bollinger keep the drift-reseed cadence, the EMA-family keep the seed division and `mul_add` recurrences. Adds the `BatchNanExt` extension trait. - **Cross-library benchmark refresh**: `compare_libraries.py` reports the median across timing rounds (`--rounds` / `--streaming-rounds`), gains `--skip-batch` / `--skip-streaming`, and runs every peer through the streaming arena (recompute for batch-only libraries). `wickra-bench` drives the batch fast paths against `kand`. - **README** benchmark section reordered streaming-first (the order-of-magnitude result), with measured TA-Lib/tulipy/pandas-ta numbers in place of the CI-only placeholders. ## Impact - Python batch ~2× faster on EMA/RSI/MACD/ATR; streaming path unchanged. - The `batch == streaming` equivalence stays bit-exact. ## Verification - `cargo fmt` · `cargo clippy --workspace --all-targets --all-features -- -D warnings` (clean) - `cargo test --workspace --all-features` — 3782 unit + 420 doc tests pass - Python `pytest` — streaming-vs-batch, known-values, input-validation, smoke pass ## Notes - Node/WASM bindings keep their existing batch; the fast paths are Python-only for now.
438 lines
14 KiB
Rust
438 lines
14 KiB
Rust
//! Average True Range (Wilder).
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use crate::error::{Error, Result};
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use crate::ohlcv::Candle;
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use crate::traits::Indicator;
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/// Average True Range with Wilder smoothing.
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///
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/// The first emitted value, by convention, appears after `period` candles: the
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/// first `period − 1` true-range values seed the Wilder average alongside the
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/// `period`-th, then the smoothed update begins.
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///
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/// # Example
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///
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/// ```
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/// use wickra_core::{Candle, Indicator, Atr};
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///
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/// let mut indicator = Atr::new(5).unwrap();
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/// let mut last = None;
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/// for i in 0..80 {
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/// let base = 100.0 + f64::from(i);
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/// let candle =
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/// Candle::new(base, base + 2.0, base - 2.0, base + 1.0, 10.0, i64::from(i)).unwrap();
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/// last = indicator.update(candle);
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/// }
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/// assert!(last.is_some());
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/// ```
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#[derive(Debug, Clone)]
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pub struct Atr {
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period: usize,
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/// `period - 1` as `f64`, precomputed for the Wilder smoothing step.
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n_minus_1: f64,
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/// `1 / period`, precomputed so the per-tick smoothing multiplies instead of
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/// divides.
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inv_period: f64,
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prev_close: Option<f64>,
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seed_buf: Vec<f64>,
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/// Smoothed ATR, valid once `seeded` is set. Bare `f64` + flag rather than
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/// `Option<f64>` so the hot recurrence avoids an enum-tag read per tick.
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avg: f64,
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seeded: bool,
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}
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impl Atr {
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/// Construct an ATR with the given Wilder period.
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///
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/// # Errors
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///
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/// Returns [`Error::PeriodZero`] if `period == 0`.
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pub fn new(period: usize) -> Result<Self> {
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if period == 0 {
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return Err(Error::PeriodZero);
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}
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Ok(Self {
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period,
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n_minus_1: (period - 1) as f64,
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inv_period: 1.0 / period as f64,
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prev_close: None,
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seed_buf: Vec::with_capacity(period),
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avg: 0.0,
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seeded: false,
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})
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}
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/// Configured period.
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pub const fn period(&self) -> usize {
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self.period
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}
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/// Current value if available.
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pub const fn value(&self) -> Option<f64> {
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if self.seeded {
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Some(self.avg)
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} else {
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None
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}
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}
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/// Vectorized batch over raw high/low/close columns: one `f64` per bar
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/// (`NaN` during warmup). The caller guarantees the three slices are equal
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/// length and finite with valid OHLC ordering (the binding validates once up
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/// front); ATR only reads high, low and the previous close.
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///
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/// For a fresh indicator long enough to seed (`n >= period`) it runs the
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/// true-range seed once and then the bare Wilder recurrence in a tight loop —
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/// no per-bar `Candle` construction/validation, no `Option`, identical
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/// division at the seed and `mul_add` afterwards, so the result is
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/// *bit-for-bit* equal to replaying `update` over the same candles. Shorter
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/// or non-fresh inputs defer to an exact `update` replay.
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pub fn batch_atr(&mut self, high: &[f64], low: &[f64], close: &[f64]) -> Vec<f64> {
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let p = self.period;
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let n = high.len();
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if self.seeded || !self.seed_buf.is_empty() || self.prev_close.is_some() || n < p {
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let mut out = vec![f64::NAN; n];
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for i in 0..n {
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let candle = Candle::new_unchecked(close[i], high[i], low[i], close[i], 0.0, 0);
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if let Some(v) = self.update(candle) {
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out[i] = v;
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}
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}
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return out;
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}
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// Warmup `[0, p-1)` is `NaN`; the first ATR is emitted at index `p - 1`.
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let mut out = vec![f64::NAN; p - 1];
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out.reserve(n - (p - 1));
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// Seed: mean of the first `period` true ranges. TR₀ has no previous close.
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let mut prev_close = close[0];
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let mut sum_tr = high[0] - low[0];
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self.seed_buf.push(sum_tr);
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for i in 1..p {
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let (h, l) = (high[i], low[i]);
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let tr = (h - l)
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.max((h - prev_close).abs())
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.max((l - prev_close).abs());
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prev_close = close[i];
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self.seed_buf.push(tr);
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sum_tr += tr;
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}
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let mut avg = sum_tr / p as f64;
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out.push(avg);
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// Steady state: Wilder smoothing, reciprocal hoisted out of the loop.
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for i in p..n {
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let (h, l) = (high[i], low[i]);
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let tr = (h - l)
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.max((h - prev_close).abs())
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.max((l - prev_close).abs());
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prev_close = close[i];
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avg = avg.mul_add(self.n_minus_1, tr) * self.inv_period;
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out.push(avg);
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}
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// Leave state where a full `update` replay would (seeded; seed_buf retained).
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self.prev_close = Some(prev_close);
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self.avg = avg;
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self.seeded = true;
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out
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}
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}
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impl Indicator for Atr {
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type Input = Candle;
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type Output = f64;
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fn update(&mut self, candle: Candle) -> Option<f64> {
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let tr = candle.true_range(self.prev_close);
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self.prev_close = Some(candle.close);
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if self.seeded {
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// Wilder smoothing with the reciprocal hoisted out of the hot path.
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let new_avg = self.avg.mul_add(self.n_minus_1, tr) * self.inv_period;
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self.avg = new_avg;
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return Some(new_avg);
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}
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self.seed_buf.push(tr);
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if self.seed_buf.len() == self.period {
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let seed = self.seed_buf.iter().copied().sum::<f64>() / self.period as f64;
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self.avg = seed;
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self.seeded = true;
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return Some(seed);
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}
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None
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}
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fn reset(&mut self) {
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self.prev_close = None;
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self.seed_buf.clear();
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self.avg = 0.0;
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self.seeded = false;
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}
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fn warmup_period(&self) -> usize {
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self.period
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}
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fn is_ready(&self) -> bool {
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self.seeded
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}
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fn name(&self) -> &'static str {
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"ATR"
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}
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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use crate::traits::BatchExt;
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use approx::assert_relative_eq;
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fn c(h: f64, l: f64, cl: f64) -> Candle {
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// ts/open/volume don't affect ATR; use safe placeholders.
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Candle::new(cl, h, l, cl, 1.0, 0).unwrap()
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}
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/// Independent reference: Wilder ATR computed straight from the definition.
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fn atr_naive(hlc: &[(f64, f64, f64)], period: usize) -> Vec<Option<f64>> {
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let n = period as f64;
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let mut out = Vec::with_capacity(hlc.len());
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let mut trs: Vec<f64> = Vec::new();
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let mut avg: Option<f64> = None;
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let mut prev_close: Option<f64> = None;
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for &(h, l, cl) in hlc {
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let tr = match prev_close {
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None => h - l,
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Some(pc) => (h - l).max((h - pc).abs()).max((l - pc).abs()),
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};
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prev_close = Some(cl);
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if let Some(a) = avg {
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let na = (a * (n - 1.0) + tr) / n;
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avg = Some(na);
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out.push(Some(na));
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} else {
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trs.push(tr);
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if trs.len() == period {
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avg = Some(trs.iter().sum::<f64>() / n);
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out.push(avg);
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} else {
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out.push(None);
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}
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}
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}
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out
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}
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#[test]
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fn rejects_zero_period() {
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assert!(matches!(Atr::new(0), Err(Error::PeriodZero)));
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}
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/// Cover the const accessors `period` / `value` (54-62) and the
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/// Indicator-impl `name` body (103-105). Existing tests inspect
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/// numeric ATR output but never query the metadata.
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#[test]
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fn accessors_and_metadata() {
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let mut atr = Atr::new(14).unwrap();
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assert_eq!(atr.period(), 14);
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assert_eq!(atr.name(), "ATR");
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assert_eq!(atr.value(), None);
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for _ in 0..14 {
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atr.update(c(11.0, 9.0, 10.0));
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}
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assert!(atr.value().is_some());
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}
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#[test]
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fn warmup_emits_on_period_th_candle() {
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let candles = vec![
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c(2.0, 1.0, 1.5),
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c(3.0, 2.0, 2.5),
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c(4.0, 3.0, 3.5),
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c(5.0, 4.0, 4.5),
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c(6.0, 5.0, 5.5),
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];
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let mut atr = Atr::new(3).unwrap();
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let out = atr.batch(&candles);
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assert!(out[0].is_none());
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assert!(out[1].is_none());
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assert!(out[2].is_some());
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assert!(out[3].is_some());
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}
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#[test]
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fn constant_range_yields_constant_atr() {
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// Every candle has H=11, L=9, C=10 -> TR=2 (no gaps).
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let candles: Vec<Candle> = (0..30).map(|_| c(11.0, 9.0, 10.0)).collect();
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let mut atr = Atr::new(14).unwrap();
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let out = atr.batch(&candles);
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for v in out.iter().skip(13).flatten() {
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assert_relative_eq!(*v, 2.0, epsilon = 1e-12);
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}
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}
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#[test]
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fn gap_up_uses_high_minus_prev_close() {
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// Previous close 5, current candle H=10 L=9 C=9.5 -> TR = max(1, 5, 4) = 5.
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let candles = vec![
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c(6.0, 4.0, 5.0), // prev close = 5
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c(10.0, 9.0, 9.5), // TR = 5
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];
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let mut atr = Atr::new(2).unwrap();
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let out = atr.batch(&candles);
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// Seed window covers TR_1 and TR_2. TR_1 = H1-L1 = 2 (no prev close). TR_2 = 5.
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// Seed = (2+5)/2 = 3.5
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assert_relative_eq!(out[1].unwrap(), 3.5, epsilon = 1e-12);
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}
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#[test]
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fn batch_equals_streaming() {
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let candles: Vec<Candle> = (0..40)
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.map(|i| {
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let mid = f64::from(i) + 10.0;
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c(mid + 0.5, mid - 0.5, mid)
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})
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.collect();
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let mut a = Atr::new(14).unwrap();
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let mut b = Atr::new(14).unwrap();
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assert_eq!(
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a.batch(&candles),
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candles.iter().map(|x| b.update(*x)).collect::<Vec<_>>()
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);
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}
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#[test]
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fn reset_clears_state() {
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let candles: Vec<Candle> = (0..20).map(|_| c(11.0, 9.0, 10.0)).collect();
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let mut atr = Atr::new(5).unwrap();
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atr.batch(&candles);
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assert!(atr.is_ready());
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atr.reset();
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assert!(!atr.is_ready());
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assert_eq!(atr.update(candles[0]), None);
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}
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#[test]
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fn never_negative() {
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let candles: Vec<Candle> = (0..200)
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.map(|i| {
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let base = 100.0 + (f64::from(i) * 0.3).sin() * 5.0;
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c(base + 1.0, base - 1.0, base)
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})
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.collect();
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let mut atr = Atr::new(14).unwrap();
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for v in atr.batch(&candles).into_iter().flatten() {
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assert!(v >= 0.0, "ATR must be non-negative: {v}");
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}
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}
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fn bits_eq(a: &[f64], b: &[f64]) -> bool {
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a.len() == b.len()
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&& a.iter()
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.zip(b)
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.all(|(x, y)| x == y || (x.is_nan() && y.is_nan()))
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}
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fn atr_replay(period: usize, high: &[f64], low: &[f64], close: &[f64]) -> Vec<f64> {
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let mut a = Atr::new(period).unwrap();
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(0..high.len())
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.map(|i| {
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let candle = Candle::new_unchecked(close[i], high[i], low[i], close[i], 0.0, 0);
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a.update(candle).unwrap_or(f64::NAN)
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})
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.collect()
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}
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/// Valid OHLC columns from a wandering base price.
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fn columns(n: usize) -> (Vec<f64>, Vec<f64>, Vec<f64>) {
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let base: Vec<f64> = (0..n)
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.map(|i| (f64::from(u32::try_from(i).unwrap()) * 0.3).sin() * 5.0 + 100.0)
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.collect();
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let high = base.iter().map(|b| b + 1.0).collect();
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let low = base.iter().map(|b| b - 1.0).collect();
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(high, low, base)
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}
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#[test]
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fn batch_atr_fast_path_is_bit_identical() {
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let (high, low, close) = columns(300);
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let mut atr = Atr::new(14).unwrap();
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let got = atr.batch_atr(&high, &low, &close);
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assert!(bits_eq(&got, &atr_replay(14, &high, &low, &close)));
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let mut ref_atr = Atr::new(14).unwrap();
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for i in 0..high.len() {
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ref_atr.update(Candle::new_unchecked(
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close[i], high[i], low[i], close[i], 0.0, 0,
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));
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}
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let next = Candle::new_unchecked(101.0, 102.0, 100.0, 101.0, 0.0, 0);
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assert_eq!(atr.update(next), ref_atr.update(next));
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}
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#[test]
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fn batch_atr_falls_back_when_not_fresh() {
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let (high, low, close) = columns(40);
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let mut atr = Atr::new(14).unwrap();
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atr.update(Candle::new_unchecked(
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close[0], high[0], low[0], close[0], 0.0, 0,
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));
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let mut ref_atr = Atr::new(14).unwrap();
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ref_atr.update(Candle::new_unchecked(
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close[0], high[0], low[0], close[0], 0.0, 0,
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));
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let want: Vec<f64> = (0..high.len())
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.map(|i| {
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ref_atr
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.update(Candle::new_unchecked(
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close[i], high[i], low[i], close[i], 0.0, 0,
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))
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.unwrap_or(f64::NAN)
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})
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.collect();
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assert!(bits_eq(&atr.batch_atr(&high, &low, &close), &want));
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}
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#[test]
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fn batch_atr_sub_period_slice_falls_back() {
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let (high, low, close) = columns(5);
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let mut atr = Atr::new(14).unwrap();
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let got = atr.batch_atr(&high, &low, &close);
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assert!(bits_eq(&got, &atr_replay(14, &high, &low, &close)));
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assert!(got.iter().all(|x| x.is_nan()));
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}
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proptest::proptest! {
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#![proptest_config(proptest::test_runner::Config::with_cases(48))]
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#[test]
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fn atr_matches_naive(
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period in 1usize..15,
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bars in proptest::collection::vec(
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(10.0_f64..1000.0, 0.0_f64..50.0, 0.0_f64..1.0),
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0..120,
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),
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) {
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// bars: (low, range, close_fraction) -> a valid OHLC candle.
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let hlc: Vec<(f64, f64, f64)> = bars
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.iter()
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.map(|&(low, range, frac)| (low + range, low, low + range * frac))
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.collect();
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let candles: Vec<Candle> = hlc.iter().map(|&(h, l, cl)| c(h, l, cl)).collect();
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let mut atr = Atr::new(period).unwrap();
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let got = atr.batch(&candles);
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let want = atr_naive(&hlc, period);
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proptest::prop_assert_eq!(got.len(), want.len());
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for (g, w) in got.iter().zip(want.iter()) {
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match (g, w) {
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(None, None) => {}
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(Some(a), Some(b)) => proptest::prop_assert!(
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(a - b).abs() <= 1e-9 * a.abs().max(1.0),
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"got={a} want={b}"
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),
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_ => proptest::prop_assert!(false, "warmup mismatch"),
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}
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}
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}
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}
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}
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