Struct MassIndex 

pub struct MassIndex { /* private fields */ }

Mass Index — Donald Dorsey’s range-expansion indicator.

The Mass Index watches the high–low range, not direction. It smooths the range with an EMA, smooths that again, takes the ratio of the two, and sums the ratio over a window:

range_t  = high_t − low_t
ratio_t  = EMA(range, ema_period) / EMA(EMA(range, ema_period), ema_period)
MassIndex = Σ ratio over sum_period

When the range widens, the single EMA pulls ahead of the double EMA, the ratio rises above 1, and the sum climbs. Dorsey’s “reversal bulge” is the Mass Index rising above 27 and then falling back below 26.5 — a sign that a range expansion is about to resolve into a trend reversal. With the conventional (ema_period = 9, sum_period = 25) a flat-range market sits at 25.

Example

use wickra_core::{Candle, Indicator, MassIndex};

let mut indicator = MassIndex::new(9, 25).unwrap();
let mut last = None;
for i in 0..80 {
    let base = 100.0 + i as f64;
    let candle =
        Candle::new(base, base + 2.0, base - 2.0, base, 10.0, i64::from(i)).unwrap();
    last = indicator.update(candle);
}
assert!(last.is_some());

Implementations

impl MassIndex

pub fn new(ema_period: usize, sum_period: usize) -> Result<Self>

Construct a new Mass Index with the EMA smoothing period and the sum window length.

Errors

Returns Error::PeriodZero if either period is 0.

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

The (ema_period, sum_period) pair.

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

Current value if available.

Trait Implementations

impl Clone for MassIndex

fn clone(&self) -> MassIndex

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for MassIndex

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

Formats the value using the given formatter.

impl Indicator for MassIndex

type Input = Candle

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, candle: Candle) -> 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.