feat: Family 01 Moving Averages — ALMA / McGinley / FRAMA / VIDYA / JMA / Alligator / EVWMA (#39)

* feat(alma): add Arnaud Legoux Moving Average

Gaussian-weighted moving average with configurable centre (offset in
[0, 1]) and kernel width (sigma > 0). Pre-computes normalised weights
at construction so each update is a single rolling window dot product.

Reference: Arnaud Legoux and Dimitrios Kouzis-Loukas, 2009.

Touchpoints:
- crates/wickra-core: alma.rs + mod.rs + lib.rs re-export
- bindings/python: PyAlma + __init__.py + test_new_indicators +
  test_known_values reference
- bindings/node: AlmaNode + index.d.ts/index.js + indicators.test.js
  factory + reference value
- bindings/wasm: wasm_scalar_indicator! macro
- fuzz: indicator_update target covers ALMA(9, 0.85, 6.0)
- crates/wickra/benches: bench_scalar entry
- README + CHANGELOG: Moving Averages row + Unreleased entry

* feat(mcginley): add McGinley Dynamic moving average

John McGinley's self-adjusting moving average with the recurrence
MD + (price - MD) / (0.6 * period * (price / MD)^4). Speeds up when
price falls below the indicator and damps when price runs above the
indicator. Seeded with the simple average of the first period inputs.

Reference: McGinley, Technical Analysis of Stocks & Commodities, 1990.

Touchpoints:
- crates/wickra-core: mcginley_dynamic.rs + mod.rs + lib.rs re-export
- bindings/python: PyMcGinleyDynamic + __init__.py + test_new_indicators
  + test_known_values reference
- bindings/node: McGinleyDynamicNode (scalar macro) + index.d.ts/index.js
  + indicators.test.js factory + reference value
- bindings/wasm: wasm_scalar_indicator! macro
- fuzz: indicator_update target covers McGinleyDynamic(10)
- crates/wickra/benches: bench_scalar entry
- README + CHANGELOG: Moving Averages row + Unreleased entry

* feat(frama): add Fractal Adaptive Moving Average

Ehlers' FRAMA adapts its smoothing constant to the fractal dimension of
the recent window: tight tracking in trends, heavy smoothing in chop.
Uses the close-only variant where max/min over each window half drive
the dimension estimate. Period must be even (default 16).

Reference: Ehlers, Fractal Adaptive Moving Average, 2005.

Touchpoints:
- crates/wickra-core: frama.rs + mod.rs + lib.rs re-export
- bindings/python: PyFrama + __init__.py + test_new_indicators +
  test_known_values reference (constant series + uptrend tracking)
- bindings/node: FramaNode (scalar macro) + index.d.ts/index.js +
  indicators.test.js factory + reference value
- bindings/wasm: wasm_scalar_indicator! macro
- fuzz: indicator_update target covers Frama(16)
- crates/wickra/benches: bench_scalar entry
- README + CHANGELOG: Moving Averages row + Unreleased entry

* feat(vidya): add Variable Index Dynamic Average

Chande's VIDYA — an EMA whose alpha scales with |CMO(cmo_period)| / 100.
Strong directional momentum lifts the smoothing constant toward the
EMA-of-period rate; flat or choppy windows shrink it toward zero so
VIDYA coasts on its previous value. Two parameters: period (14) and
cmo_period (9). Reuses the existing wickra-core Cmo internally.

Reference: Chande, Stocks & Commodities, 1992.

Also fixes a silent gap from d37fbd1 (feat(frama)): the PyFrama Python
class wrapper and its add_class registration were dropped because the
two edits hit "File has not been read yet" errors that scrolled past
in a batch. Adds them here alongside VIDYA's bindings.

Touchpoints (VIDYA): vidya.rs + mod.rs + lib.rs re-export, PyVidya +
__init__.py + test_new_indicators + test_known_values reference,
VidyaNode (manual two-param binding) + index.d.ts/index.js +
indicators.test.js factory + reference, wasm_scalar_indicator! macro,
fuzz target, bench, README + CHANGELOG.

* feat(jma): add Jurik Moving Average

Three-stage filter reconstruction of Mark Jurik's adaptive MA (the
algorithm is proprietary; this is the form used by most open-source
ports since the 1999 TASC article). Parameters: period (14), phase in
[-100, 100] (0), power in 1..=4 (2). State is seeded by setting
e0 = JMA = first input so a constant input stream is reproduced exactly.

Touchpoints: jma.rs + mod.rs + lib.rs re-export, PyJma + __init__.py +
test_new_indicators + test_known_values reference, JmaNode (manual
three-param binding) + index.d.ts/index.js + indicators.test.js factory
+ reference, wasm_scalar_indicator! macro, fuzz target, bench, README +
CHANGELOG.

* feat(alligator): add Bill Williams Alligator

Three SMMA lines (Jaw / Teeth / Lips) over the median price
(high + low) / 2 with default periods 13 / 8 / 5. Multi-output
indicator returning AlligatorOutput { jaw, teeth, lips }. The
original chart variant shifts each line forward for display; we
publish the unshifted SMMA values and leave the visual shift to
the consumer.

Reference: Bill Williams, Trading Chaos, 1995.

Touchpoints: alligator.rs + mod.rs + lib.rs re-export, PyAlligator
(Candle input, returns 3-tuple, ndarray (n, 3) batch) + __init__.py
+ test_new_indicators + test_known_values reference, AlligatorNode +
AlligatorValue + index.d.ts/index.js + indicators.test.js multi
factory + reference, WasmAlligator (manual JsValue object) +
candle-fuzz target + README + CHANGELOG.

* feat(evwma): add Elastic Volume-Weighted Moving Average

Christian P. Fries' elastic recurrence where the smoothing weight is the
bar's volume relative to the running window total:

  V_sum_t = sum of volumes over the last period candles
  EVWMA_t = ((V_sum_t - v_t) * EVWMA_{t-1} + v_t * close_t) / V_sum_t

A bar whose volume is small barely moves the average; a bar that
dominates the window pulls it strongly toward that bar's close. Seeded
with the close of the first full window; holds its previous value if
the entire window has zero volume.

Reference: Fries, Wilmott Magazine, 2001.

Touchpoints: evwma.rs + mod.rs + lib.rs re-export, PyEvwma (close +
volume batch) + __init__.py + test_new_indicators CANDLE_SCALAR +
test_known_values reference, EvwmaNode + index.d.ts/index.js +
indicators.test.js candleScalar factory + reference, WasmEvwma,
candle-fuzz target + README + CHANGELOG.

* ci: Force local wheel install in Python jobs

Use --no-index --no-deps so the Python matrix installs the freshly
built wheel from dist/ and never falls back to PyPI. Previously pip
sometimes picked the released 0.2.x wheel on macOS / Windows when its
platform tag was a wider match than the local build, which made the
job test the released package and miss any new symbols added in the
PR (e.g. AttributeError: module 'wickra' has no attribute 'ALMA').
numpy is already installed by the preceding pip step, so --no-deps
is safe.
This commit is contained in:
kingchenc
2026-05-25 15:01:14 +02:00
committed by GitHub
parent 178fbfd68e
commit 466faddd87
23 changed files with 2765 additions and 21 deletions
@@ -0,0 +1,223 @@
//! Bill Williams' Alligator indicator.
use crate::error::{Error, Result};
use crate::indicators::smma::Smma;
use crate::ohlcv::Candle;
use crate::traits::Indicator;
/// Alligator output: three smoothed moving averages of the median price
/// `(high + low) / 2`.
#[derive(Debug, Clone, Copy, PartialEq)]
pub struct AlligatorOutput {
/// `Jaw` — the slowest line (default period 13).
pub jaw: f64,
/// `Teeth` — the middle line (default period 8).
pub teeth: f64,
/// `Lips` — the fastest line (default period 5).
pub lips: f64,
}
/// Bill Williams' Alligator: three `SMMA`s of the median price `(high + low) / 2`
/// with different periods. Classic parameters are `(jaw = 13, teeth = 8, lips = 5)`.
///
/// The original chart variant additionally shifts each line forward by a fixed
/// number of bars for display (Jaw +8, Teeth +5, Lips +3). Wickra publishes the
/// *unshifted* `SMMA` values — the consumer can apply the visual shift on the
/// chart side. The indicator emits values once all three `SMMA`s have warmed
/// up, i.e. after `max(jaw, teeth, lips) = jaw` candles.
///
/// Reference: Bill Williams, *Trading Chaos*, 1995.
///
/// # Example
///
/// ```
/// use wickra_core::{Alligator, Candle, Indicator};
///
/// let mut alligator = Alligator::classic();
/// let mut last = None;
/// for i in 0..40 {
/// let base = 100.0 + f64::from(i);
/// let candle =
/// Candle::new(base, base + 1.0, base - 1.0, base, 1.0, i64::from(i)).unwrap();
/// last = alligator.update(candle);
/// }
/// assert!(last.is_some());
/// ```
#[derive(Debug, Clone)]
pub struct Alligator {
jaw_period: usize,
teeth_period: usize,
lips_period: usize,
jaw: Smma,
teeth: Smma,
lips: Smma,
}
impl Alligator {
/// # Errors
/// Returns [`Error::PeriodZero`] if any period is zero.
pub fn new(jaw_period: usize, teeth_period: usize, lips_period: usize) -> Result<Self> {
if jaw_period == 0 || teeth_period == 0 || lips_period == 0 {
return Err(Error::PeriodZero);
}
Ok(Self {
jaw_period,
teeth_period,
lips_period,
jaw: Smma::new(jaw_period)?,
teeth: Smma::new(teeth_period)?,
lips: Smma::new(lips_period)?,
})
}
/// Bill Williams' classic parameters: `(jaw = 13, teeth = 8, lips = 5)`.
pub fn classic() -> Self {
Self::new(13, 8, 5).expect("classic Alligator parameters are valid")
}
/// Configured `(jaw_period, teeth_period, lips_period)`.
pub const fn periods(&self) -> (usize, usize, usize) {
(self.jaw_period, self.teeth_period, self.lips_period)
}
}
impl Indicator for Alligator {
type Input = Candle;
type Output = AlligatorOutput;
fn update(&mut self, candle: Candle) -> Option<AlligatorOutput> {
let median = f64::midpoint(candle.high, candle.low);
// Feed every `SMMA` on every bar so they warm up in parallel; gating
// the longer lines behind the shorter ones would starve them during
// their own warmup.
let lips = self.lips.update(median);
let teeth = self.teeth.update(median);
let jaw = self.jaw.update(median);
Some(AlligatorOutput {
jaw: jaw?,
teeth: teeth?,
lips: lips?,
})
}
fn reset(&mut self) {
self.jaw.reset();
self.teeth.reset();
self.lips.reset();
}
fn warmup_period(&self) -> usize {
// All three SMMAs run on every bar, so readiness is gated by the
// longest period — the Jaw with the default parameters.
self.jaw_period.max(self.teeth_period).max(self.lips_period)
}
fn is_ready(&self) -> bool {
self.jaw.is_ready() && self.teeth.is_ready() && self.lips.is_ready()
}
fn name(&self) -> &'static str {
"Alligator"
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::traits::BatchExt;
use approx::assert_relative_eq;
fn candle(high: f64, low: f64, ts: i64) -> Candle {
let close = f64::midpoint(high, low);
Candle::new(close, high, low, close, 1.0, ts).unwrap()
}
#[test]
fn rejects_zero_period() {
assert!(matches!(Alligator::new(0, 8, 5), Err(Error::PeriodZero)));
assert!(matches!(Alligator::new(13, 0, 5), Err(Error::PeriodZero)));
assert!(matches!(Alligator::new(13, 8, 0), Err(Error::PeriodZero)));
}
#[test]
fn accessors_and_metadata() {
let alligator = Alligator::classic();
assert_eq!(alligator.periods(), (13, 8, 5));
assert_eq!(alligator.warmup_period(), 13);
assert_eq!(alligator.name(), "Alligator");
}
#[test]
fn constant_series_yields_the_constant() {
// Median price = 10 for every bar, so each SMMA seeds to 10 and stays.
let mut alligator = Alligator::classic();
let candles: Vec<Candle> = (0..40).map(|i| candle(11.0, 9.0, i)).collect();
let out = alligator.batch(&candles);
for v in out.iter().skip(12).flatten() {
assert_relative_eq!(v.jaw, 10.0, epsilon = 1e-12);
assert_relative_eq!(v.teeth, 10.0, epsilon = 1e-12);
assert_relative_eq!(v.lips, 10.0, epsilon = 1e-12);
}
}
#[test]
fn warmup_emits_first_value_at_longest_period() {
let mut alligator = Alligator::new(5, 3, 2).unwrap();
let candles: Vec<Candle> = (0..6).map(|i| candle(11.0, 9.0, i)).collect();
let out = alligator.batch(&candles);
for v in out.iter().take(4) {
assert!(v.is_none());
}
assert!(out[4].is_some());
}
#[test]
fn pure_uptrend_ordering() {
// On a clean uptrend the fastest line (Lips, smallest SMMA) leads the
// slowest line (Jaw) — lips > teeth > jaw at the latest bar.
let mut alligator = Alligator::classic();
let candles: Vec<Candle> = (0_i64..80)
.map(|i| candle(10.0 + i as f64, 9.0 + i as f64, i))
.collect();
let out = alligator.batch(&candles);
let last = out.last().unwrap().unwrap();
assert!(
last.lips > last.teeth,
"lips {} > teeth {}",
last.lips,
last.teeth
);
assert!(
last.teeth > last.jaw,
"teeth {} > jaw {}",
last.teeth,
last.jaw
);
}
#[test]
fn batch_equals_streaming() {
let candles: Vec<Candle> = (0..80_i64)
.map(|i| {
let base = 100.0 + (i as f64 * 0.2).sin() * 5.0;
candle(base + 1.0, base - 1.0, i)
})
.collect();
let mut a = Alligator::classic();
let mut b = Alligator::classic();
assert_eq!(
a.batch(&candles),
candles.iter().map(|c| b.update(*c)).collect::<Vec<_>>()
);
}
#[test]
fn reset_clears_state() {
let mut alligator = Alligator::classic();
let candles: Vec<Candle> = (0..40).map(|i| candle(11.0, 9.0, i)).collect();
alligator.batch(&candles);
assert!(alligator.is_ready());
alligator.reset();
assert!(!alligator.is_ready());
}
}
+335
View File
@@ -0,0 +1,335 @@
//! Arnaud Legoux Moving Average (ALMA).
use std::collections::VecDeque;
use crate::error::{Error, Result};
use crate::traits::Indicator;
/// Arnaud Legoux Moving Average — a Gaussian-weighted moving average.
///
/// Each output is a weighted sum of the last `period` inputs:
///
/// ```text
/// w[i] = exp(-(i - m)^2 / (2 * s^2)) for i in 0..period
/// m = offset * (period - 1)
/// s = period / sigma
/// ALMA = sum(price[i] * w[i]) / sum(w[i])
/// ```
///
/// The Gaussian is centred on the relative index `offset * (period - 1)`, so
/// `offset = 0.85` puts the peak near the newest sample (responsive), while
/// `offset = 0.5` centres the peak in the middle of the window (smooth).
/// `sigma` controls how concentrated the Gaussian is: larger `sigma` ->
/// narrower kernel, smaller `sigma` -> broader (closer to SMA).
///
/// Reference: Arnaud Legoux and Dimitrios Kouzis-Loukas, 2009.
///
/// # Defaults
///
/// The community-standard parameters are `period = 9`, `offset = 0.85`,
/// `sigma = 6.0`. The first output lands after exactly `period` inputs.
///
/// # Example
///
/// ```
/// use wickra_core::{Alma, Indicator};
///
/// let mut alma = Alma::new(9, 0.85, 6.0).unwrap();
/// let mut last = None;
/// for i in 0..40 {
/// last = alma.update(100.0 + f64::from(i));
/// }
/// assert!(last.is_some());
/// ```
#[derive(Debug, Clone)]
pub struct Alma {
period: usize,
offset: f64,
sigma: f64,
/// Pre-computed, normalised weights (sum to 1). `weights[0]` is the oldest
/// sample in the window, `weights[period - 1]` the newest.
weights: Vec<f64>,
window: VecDeque<f64>,
current: Option<f64>,
}
impl Alma {
/// Construct a new ALMA with the given period, offset and sigma.
///
/// # Errors
///
/// - [`Error::PeriodZero`] if `period == 0`.
/// - [`Error::InvalidPeriod`] if `offset` is outside `[0.0, 1.0]` or
/// `sigma <= 0.0` or either of `offset` / `sigma` is non-finite.
pub fn new(period: usize, offset: f64, sigma: f64) -> Result<Self> {
if period == 0 {
return Err(Error::PeriodZero);
}
if !offset.is_finite() || !(0.0..=1.0).contains(&offset) {
return Err(Error::InvalidPeriod {
message: "ALMA offset must be a finite value in [0, 1]",
});
}
if !sigma.is_finite() || sigma <= 0.0 {
return Err(Error::InvalidPeriod {
message: "ALMA sigma must be a finite positive value",
});
}
let m = offset * (period as f64 - 1.0);
let s = period as f64 / sigma;
let denom = 2.0 * s * s;
// The raw Gaussian weights sum to a strictly positive value because
// every term is `exp(_) > 0`, so the normalisation below cannot divide
// by zero.
let mut raw: Vec<f64> = (0..period)
.map(|i| (-((i as f64 - m).powi(2)) / denom).exp())
.collect();
let sum: f64 = raw.iter().sum();
for w in &mut raw {
*w /= sum;
}
Ok(Self {
period,
offset,
sigma,
weights: raw,
window: VecDeque::with_capacity(period),
current: None,
})
}
/// Construct ALMA with the community-standard parameters
/// `(period = 9, offset = 0.85, sigma = 6.0)`.
pub fn classic() -> Self {
Self::new(9, 0.85, 6.0).expect("classic ALMA parameters are valid")
}
/// Configured period.
pub const fn period(&self) -> usize {
self.period
}
/// Configured offset.
pub const fn offset(&self) -> f64 {
self.offset
}
/// Configured sigma.
pub const fn sigma(&self) -> f64 {
self.sigma
}
}
impl Indicator for Alma {
type Input = f64;
type Output = f64;
fn update(&mut self, input: f64) -> Option<f64> {
if !input.is_finite() {
return self.current;
}
if self.window.len() == self.period {
self.window.pop_front();
}
self.window.push_back(input);
if self.window.len() < self.period {
return None;
}
let mut acc = 0.0;
for (w, p) in self.weights.iter().zip(self.window.iter()) {
acc += w * p;
}
self.current = Some(acc);
Some(acc)
}
fn reset(&mut self) {
self.window.clear();
self.current = None;
}
fn warmup_period(&self) -> usize {
self.period
}
fn is_ready(&self) -> bool {
self.current.is_some()
}
fn name(&self) -> &'static str {
"ALMA"
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::traits::BatchExt;
use approx::assert_relative_eq;
#[test]
fn rejects_zero_period() {
assert!(matches!(Alma::new(0, 0.85, 6.0), Err(Error::PeriodZero)));
}
#[test]
fn rejects_invalid_offset() {
assert!(matches!(
Alma::new(9, -0.1, 6.0),
Err(Error::InvalidPeriod { .. })
));
assert!(matches!(
Alma::new(9, 1.1, 6.0),
Err(Error::InvalidPeriod { .. })
));
assert!(matches!(
Alma::new(9, f64::NAN, 6.0),
Err(Error::InvalidPeriod { .. })
));
}
#[test]
fn rejects_invalid_sigma() {
assert!(matches!(
Alma::new(9, 0.85, 0.0),
Err(Error::InvalidPeriod { .. })
));
assert!(matches!(
Alma::new(9, 0.85, -1.0),
Err(Error::InvalidPeriod { .. })
));
assert!(matches!(
Alma::new(9, 0.85, f64::INFINITY),
Err(Error::InvalidPeriod { .. })
));
}
#[test]
fn accessors_and_metadata() {
let alma = Alma::new(9, 0.85, 6.0).unwrap();
assert_eq!(alma.period(), 9);
assert_eq!(alma.warmup_period(), 9);
assert_eq!(alma.name(), "ALMA");
assert!((alma.offset() - 0.85).abs() < 1e-12);
assert!((alma.sigma() - 6.0).abs() < 1e-12);
// Weights are normalised by construction.
let sum: f64 = alma.weights.iter().sum();
assert_relative_eq!(sum, 1.0, epsilon = 1e-12);
}
#[test]
fn classic_factory() {
let a = Alma::classic();
assert_eq!(a.period(), 9);
assert!((a.offset() - 0.85).abs() < 1e-12);
assert!((a.sigma() - 6.0).abs() < 1e-12);
}
#[test]
fn constant_series_yields_the_constant() {
// Normalised weights sum to 1, so any constant is reproduced exactly.
let mut alma = Alma::new(9, 0.85, 6.0).unwrap();
let out = alma.batch(&[42.0_f64; 40]);
for v in out.iter().skip(8).flatten() {
assert_relative_eq!(*v, 42.0, epsilon = 1e-12);
}
}
#[test]
fn warmup_emits_first_value_at_period() {
let mut alma = Alma::new(5, 0.85, 6.0).unwrap();
for i in 0..4 {
assert_eq!(alma.update(f64::from(i)), None);
}
assert!(alma.update(4.0).is_some());
}
#[test]
fn reference_value_period_3() {
// ALMA(period=3, offset=0.85, sigma=6) on [10, 20, 30].
// m = 0.85 * 2 = 1.7; s = 3 / 6 = 0.5; 2*s^2 = 0.5.
// Independently compute the normalised Gaussian weights and the
// expected weighted sum, then check the indicator output matches.
// Computing the expectation here (rather than pinning a printed
// constant) keeps the test stable across libm `exp` implementations.
let mut alma = Alma::new(3, 0.85, 6.0).unwrap();
alma.update(10.0);
alma.update(20.0);
let v = alma.update(30.0).expect("ALMA emits after period");
let w0 = (-((0.0_f64 - 1.7).powi(2)) / 0.5).exp();
let w1 = (-((1.0_f64 - 1.7).powi(2)) / 0.5).exp();
let w2 = (-((2.0_f64 - 1.7).powi(2)) / 0.5).exp();
let s = w0 + w1 + w2;
let expected = (10.0 * w0 + 20.0 * w1 + 30.0 * w2) / s;
// The weighted sum is heavily skewed toward the newest sample so the
// output must sit close to but below the latest input (30).
assert!(v > 25.0 && v < 30.0, "ALMA(3) on [10,20,30] = {v}");
assert_relative_eq!(v, expected, epsilon = 1e-12);
}
#[test]
fn offset_zero_centres_on_oldest_sample() {
// With offset = 0 the Gaussian peaks at index 0, so ALMA leans toward
// the oldest sample in the window and away from the newest.
let mut alma = Alma::new(5, 0.0, 6.0).unwrap();
let series: Vec<f64> = (1..=5).map(f64::from).collect();
let mut last = None;
for p in &series {
last = alma.update(*p);
}
let v = last.unwrap();
let mean = series.iter().sum::<f64>() / series.len() as f64;
// Oldest sample is 1.0, mean is 3.0; an offset-0 ALMA should sit
// strictly below the mean.
assert!(v < mean, "{v} should be less than {mean}");
}
#[test]
fn offset_one_centres_on_newest_sample() {
// Symmetric to the above: offset = 1 leans toward the newest sample.
let mut alma = Alma::new(5, 1.0, 6.0).unwrap();
let series: Vec<f64> = (1..=5).map(f64::from).collect();
let mut last = None;
for p in &series {
last = alma.update(*p);
}
let v = last.unwrap();
let mean = series.iter().sum::<f64>() / series.len() as f64;
assert!(v > mean, "{v} should exceed {mean}");
}
#[test]
fn batch_equals_streaming() {
let prices: Vec<f64> = (1..=100)
.map(|i| (f64::from(i) * 0.2).sin() * 5.0 + f64::from(i) * 0.1)
.collect();
let mut a = Alma::new(9, 0.85, 6.0).unwrap();
let mut b = Alma::new(9, 0.85, 6.0).unwrap();
assert_eq!(
a.batch(&prices),
prices.iter().map(|p| b.update(*p)).collect::<Vec<_>>()
);
}
#[test]
fn reset_clears_state() {
let mut alma = Alma::new(9, 0.85, 6.0).unwrap();
alma.batch(&(1..=40).map(f64::from).collect::<Vec<_>>());
assert!(alma.is_ready());
alma.reset();
assert!(!alma.is_ready());
assert_eq!(alma.update(1.0), None);
}
#[test]
fn ignores_non_finite_input() {
let mut alma = Alma::new(5, 0.85, 6.0).unwrap();
alma.batch(&(1..=5).map(f64::from).collect::<Vec<_>>());
let before = alma.update(6.0).unwrap();
// Non-finite inputs leave the window/current untouched.
assert_eq!(alma.update(f64::NAN), Some(before));
assert_eq!(alma.update(f64::INFINITY), Some(before));
}
}
+238
View File
@@ -0,0 +1,238 @@
//! Elastic Volume-Weighted Moving Average (EVWMA).
use std::collections::VecDeque;
use crate::error::{Error, Result};
use crate::ohlcv::Candle;
use crate::traits::Indicator;
/// Christian P. Fries' Elastic Volume-Weighted Moving Average.
///
/// Unlike `VWMA` which is a per-bar weighted mean, `EVWMA` runs an
/// "elastic" recurrence whose smoothing weight is the bar's volume relative
/// to the running window-volume:
///
/// ```text
/// V_sum_t = Σ volume_i over the last `period` candles
/// EVWMA_t = ((V_sum_t - volume_t) * EVWMA_{t-1} + volume_t * close_t) / V_sum_t
/// ```
///
/// A bar whose volume is small compared to the window total barely moves the
/// average; a bar whose volume dominates the window pulls it strongly toward
/// the bar's close. The series is seeded with the close of the first candle
/// after the volume window has filled (i.e. after `period` candles).
///
/// If `V_sum_t == 0` (every candle in the window has zero volume), the
/// recurrence is undefined; the indicator holds its previous value.
///
/// Reference: Christian P. Fries, *Wilmott Magazine*, 2001.
///
/// # Example
///
/// ```
/// use wickra_core::{Candle, Evwma, Indicator};
///
/// let mut evwma = Evwma::new(20).unwrap();
/// let mut last = None;
/// for i in 0..40 {
/// let p = 100.0 + f64::from(i);
/// let candle = Candle::new(p, p + 1.0, p - 1.0, p, 10.0, i64::from(i)).unwrap();
/// last = evwma.update(candle);
/// }
/// assert!(last.is_some());
/// ```
#[derive(Debug, Clone)]
pub struct Evwma {
period: usize,
/// Rolling window of `(close, volume)` pairs, oldest at the front.
window: VecDeque<(f64, f64)>,
sum_v: f64,
current: Option<f64>,
}
impl Evwma {
/// # Errors
/// Returns [`Error::PeriodZero`] if `period == 0`.
pub fn new(period: usize) -> Result<Self> {
if period == 0 {
return Err(Error::PeriodZero);
}
Ok(Self {
period,
window: VecDeque::with_capacity(period),
sum_v: 0.0,
current: None,
})
}
/// Configured period.
pub const fn period(&self) -> usize {
self.period
}
/// Current value if available.
pub const fn value(&self) -> Option<f64> {
self.current
}
}
impl Indicator for Evwma {
type Input = Candle;
type Output = f64;
fn update(&mut self, candle: Candle) -> Option<f64> {
let close = candle.close;
let volume = candle.volume;
if self.window.len() == self.period {
let (_, old_v) = self.window.pop_front().expect("window is non-empty");
self.sum_v -= old_v;
}
self.window.push_back((close, volume));
self.sum_v += volume;
if self.window.len() < self.period {
return None;
}
// The volume sum may be zero (every bar in the window had zero
// volume); the recurrence is undefined, so seed/hold instead.
if self.sum_v <= 0.0 {
if self.current.is_none() {
self.current = Some(close);
}
return self.current;
}
let prev = self.current.unwrap_or(close);
let next = ((self.sum_v - volume) * prev + volume * close) / self.sum_v;
self.current = Some(next);
Some(next)
}
fn reset(&mut self) {
self.window.clear();
self.sum_v = 0.0;
self.current = None;
}
fn warmup_period(&self) -> usize {
self.period
}
fn is_ready(&self) -> bool {
self.current.is_some()
}
fn name(&self) -> &'static str {
"EVWMA"
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::traits::BatchExt;
use approx::assert_relative_eq;
fn candle(close: f64, volume: f64, ts: i64) -> Candle {
Candle::new(close, close, close, close, volume, ts).unwrap()
}
#[test]
fn rejects_zero_period() {
assert!(matches!(Evwma::new(0), Err(Error::PeriodZero)));
}
#[test]
fn accessors_and_metadata() {
let mut e = Evwma::new(5).unwrap();
assert_eq!(e.period(), 5);
assert_eq!(e.warmup_period(), 5);
assert_eq!(e.name(), "EVWMA");
assert_eq!(e.value(), None);
for i in 0..5 {
e.update(candle(10.0, 1.0, i));
}
assert!(e.value().is_some());
}
#[test]
fn constant_series_yields_the_constant() {
// A flat close — every (V_sum - v) * prev + v * close reduces to
// V_sum * close, so the recurrence preserves the constant after the
// first seeded sample.
let mut e = Evwma::new(5).unwrap();
let candles: Vec<Candle> = (0..30).map(|i| candle(42.0, 3.0, i)).collect();
let out = e.batch(&candles);
for v in out.iter().skip(4).flatten() {
assert_relative_eq!(*v, 42.0, epsilon = 1e-12);
}
}
#[test]
fn reference_value_period_2() {
// EVWMA(2). Bars: (close, volume) = (10, 1), (20, 3), (30, 1).
// Bar 1: window not full (size 1) -> None.
// Bar 2: window full, sum_v = 4, prev seeds to 20.
// EVWMA = ((4 - 3) * 20 + 3 * 20) / 4 = 80 / 4 = 20.
// Bar 3: window slides, sum_v = 4 (drops the 1, gains the 1).
// EVWMA = ((4 - 1) * 20 + 1 * 30) / 4 = (60 + 30) / 4 = 22.5.
let mut e = Evwma::new(2).unwrap();
assert_eq!(e.update(candle(10.0, 1.0, 0)), None);
assert_relative_eq!(
e.update(candle(20.0, 3.0, 1)).unwrap(),
20.0,
epsilon = 1e-12
);
assert_relative_eq!(
e.update(candle(30.0, 1.0, 2)).unwrap(),
22.5,
epsilon = 1e-12
);
}
#[test]
fn warmup_emits_first_value_at_period() {
let mut e = Evwma::new(4).unwrap();
for i in 0..3 {
assert_eq!(e.update(candle(10.0, 1.0, i)), None);
}
assert!(e.update(candle(10.0, 1.0, 3)).is_some());
}
#[test]
fn zero_volume_window_holds_value() {
// Every bar has zero volume: no participation, so the recurrence
// can't move and EVWMA simply seeds to the first close.
let mut e = Evwma::new(3).unwrap();
e.update(candle(10.0, 0.0, 0));
e.update(candle(15.0, 0.0, 1));
let v = e.update(candle(20.0, 0.0, 2)).unwrap();
assert_relative_eq!(v, 20.0, epsilon = 1e-12);
// Next bar still flat-zero volume: holds 20.
let v2 = e.update(candle(50.0, 0.0, 3)).unwrap();
assert_relative_eq!(v2, 20.0, epsilon = 1e-12);
}
#[test]
fn batch_equals_streaming() {
let candles: Vec<Candle> = (0..60_i64)
.map(|i| {
let c = 100.0 + (i as f64 * 0.3).sin() * 8.0;
candle(c, 1.0 + (i % 7) as f64, i)
})
.collect();
let batch = Evwma::new(10).unwrap().batch(&candles);
let mut b = Evwma::new(10).unwrap();
let streamed: Vec<_> = candles.iter().map(|c| b.update(*c)).collect();
assert_eq!(batch, streamed);
}
#[test]
fn reset_clears_state() {
let mut e = Evwma::new(3).unwrap();
let candles: Vec<Candle> = (0..10).map(|i| candle(10.0 + i as f64, 2.0, i)).collect();
e.batch(&candles);
assert!(e.is_ready());
e.reset();
assert!(!e.is_ready());
assert_eq!(e.update(candle(10.0, 1.0, 0)), None);
}
}
+259
View File
@@ -0,0 +1,259 @@
//! Fractal Adaptive Moving Average (FRAMA).
use std::collections::VecDeque;
use crate::error::{Error, Result};
use crate::traits::Indicator;
/// Ehlers' Fractal Adaptive Moving Average.
///
/// FRAMA picks its smoothing constant from the fractal dimension `D` of the
/// recent window: in a trending (low-`D`) market it follows price tightly, in
/// a choppy (high-`D`) market it smooths heavily. The window of `period`
/// closes is split into two equal halves; the fractal dimension comes from
/// the price ranges of the halves vs. the whole window:
///
/// ```text
/// N1 = (max(first half) - min(first half)) / (period / 2)
/// N2 = (max(second half) - min(second half)) / (period / 2)
/// N3 = (max(window) - min(window)) / period
/// D = (log(N1 + N2) - log(N3)) / log(2)
/// alpha = exp(-4.6 * (D - 1)) clamped to [0.01, 1.0]
/// ```
///
/// The output is an EMA-like recurrence
/// `FRAMA_t = alpha * close_t + (1 - alpha) * FRAMA_{t - 1}`, seeded with the
/// first close. `period` must be even and at least 2.
///
/// Reference: John F. Ehlers, *Fractal Adaptive Moving Average*, 2005.
///
/// # Example
///
/// ```
/// use wickra_core::{Frama, Indicator};
///
/// let mut frama = Frama::new(16).unwrap();
/// let mut last = None;
/// for i in 0..40 {
/// last = frama.update(100.0 + f64::from(i));
/// }
/// assert!(last.is_some());
/// ```
#[derive(Debug, Clone)]
pub struct Frama {
period: usize,
half: usize,
window: VecDeque<f64>,
current: Option<f64>,
}
impl Frama {
/// # Errors
/// - [`Error::PeriodZero`] if `period == 0`.
/// - [`Error::InvalidPeriod`] if `period` is odd or below 2.
pub fn new(period: usize) -> Result<Self> {
if period == 0 {
return Err(Error::PeriodZero);
}
if period < 2 {
return Err(Error::InvalidPeriod {
message: "FRAMA period must be at least 2",
});
}
if period % 2 != 0 {
return Err(Error::InvalidPeriod {
message: "FRAMA period must be even",
});
}
Ok(Self {
period,
half: period / 2,
window: VecDeque::with_capacity(period),
current: None,
})
}
/// Configured period.
pub const fn period(&self) -> usize {
self.period
}
}
impl Indicator for Frama {
type Input = f64;
type Output = f64;
fn update(&mut self, input: f64) -> Option<f64> {
if !input.is_finite() {
return self.current;
}
if self.window.len() == self.period {
self.window.pop_front();
}
self.window.push_back(input);
if self.window.len() < self.period {
return None;
}
let half = self.half;
let mut h_first = f64::NEG_INFINITY;
let mut l_first = f64::INFINITY;
let mut h_second = f64::NEG_INFINITY;
let mut l_second = f64::INFINITY;
let mut h_whole = f64::NEG_INFINITY;
let mut l_whole = f64::INFINITY;
for (i, &p) in self.window.iter().enumerate() {
if p > h_whole {
h_whole = p;
}
if p < l_whole {
l_whole = p;
}
if i < half {
if p > h_first {
h_first = p;
}
if p < l_first {
l_first = p;
}
} else {
if p > h_second {
h_second = p;
}
if p < l_second {
l_second = p;
}
}
}
let half_f = half as f64;
let period_f = self.period as f64;
let n1 = (h_first - l_first) / half_f;
let n2 = (h_second - l_second) / half_f;
let n3 = (h_whole - l_whole) / period_f;
let alpha = if n1 > 0.0 && n2 > 0.0 && n3 > 0.0 {
let d = ((n1 + n2).ln() - n3.ln()) / 2.0_f64.ln();
(-4.6 * (d - 1.0)).exp().clamp(0.01, 1.0)
} else {
// Degenerate (perfectly flat half or whole window): use the slowest
// smoothing so the indicator coasts on its previous value.
0.01
};
let prev = self.current.unwrap_or(input);
let next = alpha * input + (1.0 - alpha) * prev;
self.current = Some(next);
Some(next)
}
fn reset(&mut self) {
self.window.clear();
self.current = None;
}
fn warmup_period(&self) -> usize {
self.period
}
fn is_ready(&self) -> bool {
self.current.is_some()
}
fn name(&self) -> &'static str {
"FRAMA"
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::traits::BatchExt;
use approx::assert_relative_eq;
#[test]
fn rejects_zero_period() {
assert!(matches!(Frama::new(0), Err(Error::PeriodZero)));
}
#[test]
fn rejects_invalid_period() {
assert!(matches!(Frama::new(1), Err(Error::InvalidPeriod { .. })));
assert!(matches!(Frama::new(3), Err(Error::InvalidPeriod { .. })));
assert!(matches!(Frama::new(15), Err(Error::InvalidPeriod { .. })));
}
#[test]
fn accessors_and_metadata() {
let frama = Frama::new(16).unwrap();
assert_eq!(frama.period(), 16);
assert_eq!(frama.warmup_period(), 16);
assert_eq!(frama.name(), "FRAMA");
}
#[test]
fn constant_series_yields_the_constant() {
// Flat input -> alpha clamps to 0.01 (degenerate ranges) and the
// EMA recurrence holds the seed value forever.
let mut frama = Frama::new(4).unwrap();
let out = frama.batch(&[42.0_f64; 30]);
for v in out.iter().skip(3).flatten() {
assert_relative_eq!(*v, 42.0, epsilon = 1e-12);
}
}
#[test]
fn warmup_emits_first_value_at_period() {
let mut frama = Frama::new(4).unwrap();
assert_eq!(frama.update(1.0), None);
assert_eq!(frama.update(2.0), None);
assert_eq!(frama.update(3.0), None);
assert!(frama.update(4.0).is_some());
}
#[test]
fn pure_uptrend_alpha_close_to_one() {
// A strict monotonic uptrend has fractal dimension ~1, so alpha is
// pushed to 1.0 and FRAMA reduces to the latest price.
let mut frama = Frama::new(4).unwrap();
let prices: Vec<f64> = (1..=8).map(f64::from).collect();
let out = frama.batch(&prices);
let last = out.last().unwrap().unwrap();
assert!(
(last - 8.0).abs() < 0.05,
"FRAMA on a clean uptrend should hug the latest close: {last}"
);
}
#[test]
fn batch_equals_streaming() {
let prices: Vec<f64> = (1..=80)
.map(|i| 100.0 + (f64::from(i) * 0.2).sin() * 5.0)
.collect();
let mut a = Frama::new(8).unwrap();
let mut b = Frama::new(8).unwrap();
assert_eq!(
a.batch(&prices),
prices.iter().map(|p| b.update(*p)).collect::<Vec<_>>()
);
}
#[test]
fn reset_clears_state() {
let mut frama = Frama::new(4).unwrap();
frama.batch(&(1..=20).map(f64::from).collect::<Vec<_>>());
assert!(frama.is_ready());
frama.reset();
assert!(!frama.is_ready());
assert_eq!(frama.update(1.0), None);
}
#[test]
fn ignores_non_finite_input() {
let mut frama = Frama::new(4).unwrap();
frama.batch(&[1.0, 2.0, 3.0, 4.0]);
let before = frama.update(5.0).unwrap();
assert_eq!(frama.update(f64::NAN), Some(before));
assert_eq!(frama.update(f64::INFINITY), Some(before));
}
}
+286
View File
@@ -0,0 +1,286 @@
//! Jurik Moving Average (JMA).
use crate::error::{Error, Result};
use crate::traits::Indicator;
/// Mark Jurik's adaptive moving average. The original algorithm is proprietary
/// and Jurik Research has never published the full source. This implementation
/// follows the widely-used three-stage filter reconstruction circulated since
/// the 1999 TASC article on the indicator — the same form used by most
/// open-source ports (`TradingView` Pine, `pandas-ta`, various MQL ports):
///
/// ```text
/// beta = 0.45 * (period - 1) / (0.45 * (period - 1) + 2)
/// alpha = beta ^ power
/// phase_ratio = clamp(phase / 100 + 1.5, 0.5, 2.5)
///
/// e0_t = (1 - alpha) * x_t + alpha * e0_{t-1}
/// e1_t = (x_t - e0_t) * (1 - beta) + beta * e1_{t-1}
/// e2_t = (e0_t + phase_ratio * e1_t - JMA_{t-1}) * (1 - alpha)^2 + alpha^2 * e2_{t-1}
/// JMA_t = JMA_{t-1} + e2_t
/// ```
///
/// The state is seeded by setting `e0 = JMA = first input`, so a constant
/// input stream is reproduced exactly from the first output onward.
///
/// # Parameters
///
/// - `period`: smoothing length (default 14).
/// - `phase`: phase shift in `[-100, 100]`. Values outside this range are
/// clamped to the boundary `phase_ratio` so the constructor never fails on
/// a finite `phase`.
/// - `power`: kernel exponent in `1..=4` (default 2 matches the popular
/// reconstruction).
///
/// # Example
///
/// ```
/// use wickra_core::{Indicator, Jma};
///
/// let mut jma = Jma::new(14, 0.0, 2).unwrap();
/// let mut last = None;
/// for i in 0..40 {
/// last = jma.update(100.0 + f64::from(i));
/// }
/// assert!(last.is_some());
/// ```
#[derive(Debug, Clone)]
pub struct Jma {
period: usize,
phase: f64,
power: u32,
beta: f64,
alpha: f64,
phase_ratio: f64,
e0: f64,
e1: f64,
e2: f64,
output: Option<f64>,
}
impl Jma {
/// # Errors
/// - [`Error::PeriodZero`] if `period == 0`.
/// - [`Error::InvalidPeriod`] if `phase` is non-finite or `power` is
/// outside `1..=4`.
pub fn new(period: usize, phase: f64, power: u32) -> Result<Self> {
if period == 0 {
return Err(Error::PeriodZero);
}
if !phase.is_finite() {
return Err(Error::InvalidPeriod {
message: "JMA phase must be a finite value",
});
}
if !(1..=4).contains(&power) {
return Err(Error::InvalidPeriod {
message: "JMA power must be in 1..=4",
});
}
let len = period as f64 - 1.0;
let beta = 0.45 * len / (0.45 * len + 2.0);
let alpha = beta.powi(i32::try_from(power).expect("power is in 1..=4"));
let phase_ratio = (phase / 100.0 + 1.5).clamp(0.5, 2.5);
Ok(Self {
period,
phase,
power,
beta,
alpha,
phase_ratio,
e0: 0.0,
e1: 0.0,
e2: 0.0,
output: None,
})
}
/// Construct JMA with the popular defaults `(period = 14, phase = 0, power = 2)`.
pub fn classic() -> Self {
Self::new(14, 0.0, 2).expect("classic JMA parameters are valid")
}
/// Configured `(period, phase, power)`.
pub const fn params(&self) -> (usize, f64, u32) {
(self.period, self.phase, self.power)
}
}
impl Indicator for Jma {
type Input = f64;
type Output = f64;
fn update(&mut self, input: f64) -> Option<f64> {
if !input.is_finite() {
return self.output;
}
let Some(prev_jma) = self.output else {
// Seed e0 and JMA to the first input so a flat series is
// reproduced exactly.
self.e0 = input;
self.output = Some(input);
return self.output;
};
self.e0 = (1.0 - self.alpha) * input + self.alpha * self.e0;
self.e1 = (input - self.e0) * (1.0 - self.beta) + self.beta * self.e1;
let one_minus_alpha = 1.0 - self.alpha;
self.e2 =
(self.e0 + self.phase_ratio * self.e1 - prev_jma) * one_minus_alpha * one_minus_alpha
+ self.alpha * self.alpha * self.e2;
let next = prev_jma + self.e2;
self.output = Some(next);
Some(next)
}
fn reset(&mut self) {
self.e0 = 0.0;
self.e1 = 0.0;
self.e2 = 0.0;
self.output = None;
}
fn warmup_period(&self) -> usize {
1
}
fn is_ready(&self) -> bool {
self.output.is_some()
}
fn name(&self) -> &'static str {
"JMA"
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::traits::BatchExt;
use approx::assert_relative_eq;
#[test]
fn rejects_zero_period() {
assert!(matches!(Jma::new(0, 0.0, 2), Err(Error::PeriodZero)));
}
#[test]
fn rejects_non_finite_phase() {
assert!(matches!(
Jma::new(14, f64::NAN, 2),
Err(Error::InvalidPeriod { .. })
));
assert!(matches!(
Jma::new(14, f64::INFINITY, 2),
Err(Error::InvalidPeriod { .. })
));
}
#[test]
fn rejects_invalid_power() {
assert!(matches!(
Jma::new(14, 0.0, 0),
Err(Error::InvalidPeriod { .. })
));
assert!(matches!(
Jma::new(14, 0.0, 5),
Err(Error::InvalidPeriod { .. })
));
}
#[test]
fn accessors_and_metadata() {
let jma = Jma::new(14, 0.0, 2).unwrap();
assert_eq!(jma.params(), (14, 0.0, 2));
assert_eq!(jma.warmup_period(), 1);
assert_eq!(jma.name(), "JMA");
}
#[test]
fn classic_factory() {
let jma = Jma::classic();
assert_eq!(jma.params(), (14, 0.0, 2));
}
#[test]
fn constant_series_yields_the_constant() {
// Seeding e0 = JMA = first input means the recurrence stays exactly
// on the constant from the very first sample.
let mut jma = Jma::new(14, 0.0, 2).unwrap();
let out = jma.batch(&[42.0_f64; 60]);
for x in out.iter().flatten() {
assert_relative_eq!(*x, 42.0, epsilon = 1e-12);
}
}
#[test]
fn extreme_phase_is_clamped() {
// phase outside [-100, 100] must produce a finite JMA series (phase
// ratio clamps to [0.5, 2.5]) rather than blow up the recurrence.
let mut a = Jma::new(14, 250.0, 2).unwrap();
let mut b = Jma::new(14, -250.0, 2).unwrap();
let prices: Vec<f64> = (1..=40).map(f64::from).collect();
for &p in &prices {
let va = a.update(p).unwrap();
let vb = b.update(p).unwrap();
assert!(va.is_finite(), "JMA(phase=+250) emitted {va}");
assert!(vb.is_finite(), "JMA(phase=-250) emitted {vb}");
}
}
#[test]
fn pure_uptrend_tracks_close() {
// Monotonic uptrend, period 5, power 2 — after enough samples the
// smoothed JMA sits close to the latest input.
let mut jma = Jma::new(5, 0.0, 2).unwrap();
let prices: Vec<f64> = (1..=80).map(f64::from).collect();
let out = jma.batch(&prices);
let last = out.last().unwrap().unwrap();
let latest = *prices.last().unwrap();
assert!(
(latest - last).abs() < 5.0,
"JMA on a long clean uptrend should track close: {last} vs {latest}"
);
}
#[test]
fn batch_equals_streaming() {
let prices: Vec<f64> = (1..=80)
.map(|i| 100.0 + (f64::from(i) * 0.2).sin() * 5.0)
.collect();
let mut a = Jma::new(14, 0.0, 2).unwrap();
let mut b = Jma::new(14, 0.0, 2).unwrap();
assert_eq!(
a.batch(&prices),
prices.iter().map(|p| b.update(*p)).collect::<Vec<_>>()
);
}
#[test]
fn reset_clears_state() {
let mut jma = Jma::new(14, 0.0, 2).unwrap();
jma.batch(&(1..=30).map(f64::from).collect::<Vec<_>>());
assert!(jma.is_ready());
jma.reset();
assert!(!jma.is_ready());
assert_eq!(jma.e0, 0.0);
}
#[test]
fn ignores_non_finite_input() {
let mut jma = Jma::new(14, 0.0, 2).unwrap();
jma.batch(&(1..=15).map(f64::from).collect::<Vec<_>>());
let before = jma.update(16.0).unwrap();
assert_eq!(jma.update(f64::NAN), Some(before));
assert_eq!(jma.update(f64::INFINITY), Some(before));
}
#[test]
fn period_one_is_pass_through() {
// beta = 0, alpha = 0 -> e2 collapses to (input - prev) and the
// recurrence reduces to JMA_t = input.
let mut jma = Jma::new(1, 0.0, 2).unwrap();
assert_eq!(jma.update(5.0), Some(5.0));
assert_relative_eq!(jma.update(10.0).unwrap(), 10.0, epsilon = 1e-12);
assert_relative_eq!(jma.update(7.0).unwrap(), 7.0, epsilon = 1e-12);
}
}
@@ -0,0 +1,224 @@
//! `McGinley` Dynamic — self-adjusting moving average.
use std::collections::VecDeque;
use crate::error::{Error, Result};
use crate::traits::Indicator;
/// John `McGinley`'s "Dynamic" — a self-adjusting moving average that speeds up
/// in downtrends and slows down in uptrends to track price more closely than
/// a fixed-period MA.
///
/// The recurrence is
///
/// ```text
/// MD_t = MD_{t-1} + (price_t - MD_{t-1}) / (K * period * (price_t / MD_{t-1})^4)
/// ```
///
/// where `K = 0.6` is `McGinley`'s original constant. The fourth-power ratio
/// term shrinks the divisor when price falls below the indicator (faster
/// catch-up) and inflates it when price runs above (more smoothing). The
/// indicator is seeded with the simple average of the first `period` inputs.
///
/// Reference: John R. `McGinley` Jr., *Technical Analysis of Stocks &
/// Commodities*, 1990.
///
/// # Example
///
/// ```
/// use wickra_core::{Indicator, McGinleyDynamic};
///
/// let mut md = McGinleyDynamic::new(10).unwrap();
/// let mut last = None;
/// for i in 0..40 {
/// last = md.update(100.0 + f64::from(i));
/// }
/// assert!(last.is_some());
/// ```
#[derive(Debug, Clone)]
pub struct McGinleyDynamic {
period: usize,
seed: VecDeque<f64>,
seed_sum: f64,
current: Option<f64>,
}
/// `McGinley`'s original constant `K` in the recurrence denominator.
const K: f64 = 0.6;
impl McGinleyDynamic {
/// # Errors
/// Returns [`Error::PeriodZero`] if `period == 0`.
pub fn new(period: usize) -> Result<Self> {
if period == 0 {
return Err(Error::PeriodZero);
}
Ok(Self {
period,
seed: VecDeque::with_capacity(period),
seed_sum: 0.0,
current: None,
})
}
/// Configured period.
pub const fn period(&self) -> usize {
self.period
}
/// Current value if available.
pub const fn value(&self) -> Option<f64> {
self.current
}
}
impl Indicator for McGinleyDynamic {
type Input = f64;
type Output = f64;
fn update(&mut self, input: f64) -> Option<f64> {
if !input.is_finite() {
return self.current;
}
if let Some(prev) = self.current {
// The recurrence divides by `(price / prev)^4`; if either side is
// zero or negative the formula blows up, so we hold the previous
// value as a defensive fallback against degenerate price series.
if prev <= 0.0 || input <= 0.0 {
return self.current;
}
let ratio = input / prev;
let divisor = K * (self.period as f64) * ratio.powi(4);
let next = prev + (input - prev) / divisor;
self.current = Some(next);
} else {
self.seed.push_back(input);
self.seed_sum += input;
if self.seed.len() == self.period {
self.current = Some(self.seed_sum / self.period as f64);
}
}
self.current
}
fn reset(&mut self) {
self.seed.clear();
self.seed_sum = 0.0;
self.current = None;
}
fn warmup_period(&self) -> usize {
self.period
}
fn is_ready(&self) -> bool {
self.current.is_some()
}
fn name(&self) -> &'static str {
"McGinleyDynamic"
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::traits::BatchExt;
use approx::assert_relative_eq;
#[test]
fn rejects_zero_period() {
assert!(matches!(McGinleyDynamic::new(0), Err(Error::PeriodZero)));
}
#[test]
fn accessors_and_metadata() {
let mut md = McGinleyDynamic::new(10).unwrap();
assert_eq!(md.period(), 10);
assert_eq!(md.warmup_period(), 10);
assert_eq!(md.name(), "McGinleyDynamic");
assert_eq!(md.value(), None);
for i in 1..=10 {
md.update(f64::from(i));
}
assert!(md.value().is_some());
}
#[test]
fn constant_series_yields_the_constant() {
// ratio = 1, so the recurrence collapses to MD + 0 / divisor = MD.
let mut md = McGinleyDynamic::new(5).unwrap();
let out = md.batch(&[42.0_f64; 30]);
for v in out.iter().skip(4).flatten() {
assert_relative_eq!(*v, 42.0, epsilon = 1e-12);
}
}
#[test]
fn warmup_emits_first_value_at_period() {
let mut md = McGinleyDynamic::new(3).unwrap();
// Seed = SMA([10, 20, 30]) = 20.0.
assert_eq!(md.update(10.0), None);
assert_eq!(md.update(20.0), None);
assert_eq!(md.update(30.0), Some(20.0));
}
#[test]
fn reference_value_recurrence() {
// Period 3, seed = SMA([10, 20, 30]) = 20.0. Then on price = 40.0:
// ratio = 40 / 20 = 2
// divisor = 0.6 * 3 * 2^4 = 0.6 * 3 * 16 = 28.8
// next = 20 + (40 - 20) / 28.8 = 20.694444...
let mut md = McGinleyDynamic::new(3).unwrap();
md.batch(&[10.0_f64, 20.0, 30.0]);
let v = md.update(40.0).unwrap();
let expected = 20.0 + 20.0 / (0.6 * 3.0 * 16.0);
assert_relative_eq!(v, expected, epsilon = 1e-12);
}
#[test]
fn batch_equals_streaming() {
let prices: Vec<f64> = (1..=80)
.map(|i| 100.0 + (f64::from(i) * 0.2).sin() * 5.0)
.collect();
let mut a = McGinleyDynamic::new(10).unwrap();
let mut b = McGinleyDynamic::new(10).unwrap();
assert_eq!(
a.batch(&prices),
prices.iter().map(|p| b.update(*p)).collect::<Vec<_>>()
);
}
#[test]
fn reset_clears_state() {
let mut md = McGinleyDynamic::new(5).unwrap();
md.batch(&(1..=30).map(f64::from).collect::<Vec<_>>());
assert!(md.is_ready());
md.reset();
assert!(!md.is_ready());
assert_eq!(md.update(1.0), None);
}
#[test]
fn ignores_non_finite_input() {
let mut md = McGinleyDynamic::new(3).unwrap();
md.batch(&[10.0_f64, 20.0, 30.0]);
let before = md.value().unwrap();
assert_eq!(md.update(f64::NAN), Some(before));
assert_eq!(md.update(f64::INFINITY), Some(before));
}
#[test]
fn holds_value_when_input_is_non_positive() {
// Defensive: a zero or negative price would make the (price/prev)^4
// divisor zero or otherwise blow up; the recurrence holds steady.
let mut md = McGinleyDynamic::new(3).unwrap();
md.batch(&[10.0_f64, 20.0, 30.0]);
let before = md.value().unwrap();
assert_eq!(md.update(0.0), Some(before));
assert_eq!(md.update(-5.0), Some(before));
// Once a positive price arrives the recurrence resumes normally.
let after = md.update(40.0).unwrap();
assert!(after > before);
}
}
+14
View File
@@ -7,6 +7,8 @@
mod accelerator_oscillator;
mod adl;
mod adx;
mod alligator;
mod alma;
mod aroon;
mod aroon_oscillator;
mod atr;
@@ -29,9 +31,12 @@ mod donchian;
mod dpo;
mod ease_of_movement;
mod ema;
mod evwma;
mod force_index;
mod frama;
mod historical_volatility;
mod hma;
mod jma;
mod kama;
mod keltner;
mod linreg;
@@ -39,6 +44,7 @@ mod linreg_angle;
mod linreg_slope;
mod macd;
mod mass_index;
mod mcginley_dynamic;
mod median_price;
mod mfi;
mod mom;
@@ -66,6 +72,7 @@ mod typical_price;
mod ulcer_index;
mod ultimate_oscillator;
mod vertical_horizontal_filter;
mod vidya;
mod vortex;
mod vpt;
mod vwap;
@@ -79,6 +86,8 @@ mod zlema;
pub use accelerator_oscillator::AcceleratorOscillator;
pub use adl::Adl;
pub use adx::{Adx, AdxOutput};
pub use alligator::{Alligator, AlligatorOutput};
pub use alma::Alma;
pub use aroon::{Aroon, AroonOutput};
pub use aroon_oscillator::AroonOscillator;
pub use atr::Atr;
@@ -101,9 +110,12 @@ pub use donchian::{Donchian, DonchianOutput};
pub use dpo::Dpo;
pub use ease_of_movement::EaseOfMovement;
pub use ema::Ema;
pub use evwma::Evwma;
pub use force_index::ForceIndex;
pub use frama::Frama;
pub use historical_volatility::HistoricalVolatility;
pub use hma::Hma;
pub use jma::Jma;
pub use kama::Kama;
pub use keltner::{Keltner, KeltnerOutput};
pub use linreg::LinearRegression;
@@ -111,6 +123,7 @@ pub use linreg_angle::LinRegAngle;
pub use linreg_slope::LinRegSlope;
pub use macd::{MacdIndicator, MacdOutput};
pub use mass_index::MassIndex;
pub use mcginley_dynamic::McGinleyDynamic;
pub use median_price::MedianPrice;
pub use mfi::Mfi;
pub use mom::Mom;
@@ -138,6 +151,7 @@ pub use typical_price::TypicalPrice;
pub use ulcer_index::UlcerIndex;
pub use ultimate_oscillator::UltimateOscillator;
pub use vertical_horizontal_filter::VerticalHorizontalFilter;
pub use vidya::Vidya;
pub use vortex::{Vortex, VortexOutput};
pub use vpt::VolumePriceTrend;
pub use vwap::{RollingVwap, Vwap};
+193
View File
@@ -0,0 +1,193 @@
//! Variable Index Dynamic Average (VIDYA).
use crate::error::{Error, Result};
use crate::indicators::cmo::Cmo;
use crate::traits::Indicator;
/// Tushar Chande's Variable Index Dynamic Average — an EMA whose smoothing
/// factor is scaled by the absolute Chande Momentum Oscillator (`CMO`).
///
/// Strong directional momentum (high `|CMO|`) pushes the effective smoothing
/// constant toward the EMA-of-`period`'s natural rate; flat / choppy windows
/// (`|CMO|` close to zero) shrink it toward zero so VIDYA coasts on its prior
/// value:
///
/// ```text
/// alpha_base = 2 / (period + 1)
/// alpha_t = alpha_base * |CMO(cmo_period)| / 100
/// VIDYA_t = alpha_t * price_t + (1 - alpha_t) * VIDYA_{t-1}
/// ```
///
/// The series is seeded with the first price emitted after the `CMO`
/// warm-up (i.e. after `cmo_period + 1` inputs).
///
/// Reference: Tushar Chande, *Stocks & Commodities*, 1992.
///
/// # Example
///
/// ```
/// use wickra_core::{Indicator, Vidya};
///
/// let mut vidya = Vidya::new(14, 9).unwrap();
/// let mut last = None;
/// for i in 0..80 {
/// last = vidya.update(100.0 + f64::from(i));
/// }
/// assert!(last.is_some());
/// ```
#[derive(Debug, Clone)]
pub struct Vidya {
period: usize,
cmo_period: usize,
alpha_base: f64,
cmo: Cmo,
current: Option<f64>,
}
impl Vidya {
/// # Errors
/// Returns [`Error::PeriodZero`] if either period is zero.
pub fn new(period: usize, cmo_period: usize) -> Result<Self> {
if period == 0 || cmo_period == 0 {
return Err(Error::PeriodZero);
}
let alpha_base = 2.0 / (period as f64 + 1.0);
Ok(Self {
period,
cmo_period,
alpha_base,
cmo: Cmo::new(cmo_period)?,
current: None,
})
}
/// Configured `(period, cmo_period)`.
pub const fn periods(&self) -> (usize, usize) {
(self.period, self.cmo_period)
}
}
impl Indicator for Vidya {
type Input = f64;
type Output = f64;
fn update(&mut self, input: f64) -> Option<f64> {
if !input.is_finite() {
return self.current;
}
let cmo = self.cmo.update(input)?;
let alpha = self.alpha_base * (cmo.abs() / 100.0);
let prev = self.current.unwrap_or(input);
let next = alpha * input + (1.0 - alpha) * prev;
self.current = Some(next);
Some(next)
}
fn reset(&mut self) {
self.cmo.reset();
self.current = None;
}
fn warmup_period(&self) -> usize {
self.cmo_period + 1
}
fn is_ready(&self) -> bool {
self.current.is_some()
}
fn name(&self) -> &'static str {
"VIDYA"
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::traits::BatchExt;
use approx::assert_relative_eq;
#[test]
fn rejects_zero_period() {
assert!(matches!(Vidya::new(0, 9), Err(Error::PeriodZero)));
assert!(matches!(Vidya::new(14, 0), Err(Error::PeriodZero)));
}
#[test]
fn accessors_and_metadata() {
let v = Vidya::new(14, 9).unwrap();
assert_eq!(v.periods(), (14, 9));
assert_eq!(v.warmup_period(), 10);
assert_eq!(v.name(), "VIDYA");
}
#[test]
fn constant_series_yields_the_constant() {
// Flat input -> CMO = 0 -> alpha = 0 -> VIDYA holds its seed value.
let mut v = Vidya::new(14, 4).unwrap();
let out = v.batch(&[42.0_f64; 30]);
for x in out.iter().skip(4).flatten() {
assert_relative_eq!(*x, 42.0, epsilon = 1e-12);
}
}
#[test]
fn pure_uptrend_alpha_equals_base() {
// Monotonic uptrend: CMO saturates at +100, so alpha = alpha_base.
// After warmup the recurrence is a plain EMA with that alpha; once
// the series is long enough VIDYA closely tracks the latest input.
let mut v = Vidya::new(2, 4).unwrap();
let prices: Vec<f64> = (1..=40).map(f64::from).collect();
let out = v.batch(&prices);
let last = out.last().unwrap().unwrap();
let latest = *prices.last().unwrap();
// alpha_base = 2/3, EMA(2) tracks close — last value is within 2 of
// the latest input after this many bars.
assert!(
(latest - last).abs() < 2.0,
"VIDYA should track close on a clean uptrend: {last} vs {latest}"
);
}
#[test]
fn warmup_emits_first_value_at_cmo_period_plus_one() {
let mut v = Vidya::new(14, 3).unwrap();
assert_eq!(v.warmup_period(), 4);
assert_eq!(v.update(10.0), None);
assert_eq!(v.update(11.0), None);
assert_eq!(v.update(12.0), None);
assert!(v.update(13.0).is_some());
}
#[test]
fn batch_equals_streaming() {
let prices: Vec<f64> = (1..=60)
.map(|i| 100.0 + (f64::from(i) * 0.2).sin() * 5.0)
.collect();
let mut a = Vidya::new(14, 9).unwrap();
let mut b = Vidya::new(14, 9).unwrap();
assert_eq!(
a.batch(&prices),
prices.iter().map(|p| b.update(*p)).collect::<Vec<_>>()
);
}
#[test]
fn reset_clears_state() {
let mut v = Vidya::new(14, 9).unwrap();
v.batch(&(1..=40).map(f64::from).collect::<Vec<_>>());
assert!(v.is_ready());
v.reset();
assert!(!v.is_ready());
assert_eq!(v.update(1.0), None);
}
#[test]
fn ignores_non_finite_input() {
let mut v = Vidya::new(14, 4).unwrap();
v.batch(&(1..=20).map(f64::from).collect::<Vec<_>>());
let before = v.update(21.0).unwrap();
assert_eq!(v.update(f64::NAN), Some(before));
assert_eq!(v.update(f64::INFINITY), Some(before));
}
}