Struct PpoHistogram 

pub struct PpoHistogram { /* private fields */ }

PPO Histogram — the ppo − signal bar of the Percentage Price Oscillator.

ppo       = 100 · (EMA_fast − EMA_slow) / EMA_slow
signal    = EMA(ppo, signal_period)
histogram = ppo − signal

Ppo itself only emits the percentage line; this indicator adds the classic 9-period signal EMA on top and reports the resulting zero-centered histogram. Because PPO is scale-free (the EMA gap is divided by the slow EMA), the histogram is comparable across instruments — a PPO histogram of 0.4 means the same relative momentum on any asset, unlike the price-unit MacdHistogram.

With Appel’s defaults fast = 12, slow = 26, signal = 9, the first value lands after slow + signal − 1 inputs — the point at which the slow EMA and then the signal EMA are both seeded.

Example

use wickra_core::{Indicator, PpoHistogram};

let mut indicator = PpoHistogram::new(12, 26, 9).unwrap();
let mut last = None;
for i in 0..80 {
    last = indicator.update(100.0 + f64::from(i));
}
assert!(last.is_some());

Implementations

impl PpoHistogram

pub fn new(fast: usize, slow: usize, signal: usize) -> Result<Self>

Construct a PPO histogram with the fast/slow EMA periods and the signal EMA period.

Errors

Returns Error::PeriodZero if any period is 0, or Error::InvalidPeriod if fast >= slow.

pub fn classic() -> Self

Default (12, 26, 9) configuration.

pub const fn periods(&self) -> (usize, usize, usize)

Configured periods as (fast, slow, signal).

pub const fn value(&self) -> Option<f64>

Current value if available.

Trait Implementations

impl Clone for PpoHistogram

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for PpoHistogram

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Indicator for PpoHistogram

type Input = f64

Type of one input data point (typically f64 for a price, or Candle / Tick).

type Output = f64

Type of one output value.

fn update(&mut self, input: f64) -> Option<f64>

Feed one new data point into the indicator and return the freshly computed output, or None if there is no value for this input.

fn reset(&mut self)

Reset all internal state, leaving the indicator equivalent to a freshly constructed instance with the same parameters.

fn warmup_period(&self) -> usize

Number of inputs required before the first non-None output can be produced.

fn is_ready(&self) -> bool

Whether the indicator has emitted at least one value since the last reset.

fn name(&self) -> &'static str

Stable, human-readable indicator name. Used by chaining and diagnostics.

fn batch_nan_into(&mut self, inputs: &[Self::Input], out: &mut [f64])

where Self::Input: Copy, Self::Output: Into<f64>,

Run the indicator over inputs, writing one output per input into the caller-owned out buffer (NaN where update returns None). It exists for every indicator whose output converts to an f64; the batch pipelines use it for the scalar f64 -> f64 ones.

fn batch_fast_into(&mut self, inputs: &[Self::Input], out: &mut [f64])

where Self::Input: Copy, Self::Output: Into<f64>,

Opt-in fast batch: like batch_nan_into, but an indicator with a vectorised kernel may reassociate its arithmetic to run it in SIMD lanes. Each value then agrees with the exact batch to within the tolerance the indicator documents (a few units in the last place), not bit for bit; warmup positions, NaN placement and the output length are identical. The kernels are deterministic: the same input produces the same bits on every platform, with or without SIMD hardware.