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) -> PpoHistogram

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 the indicator is still warming up.

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.