Struct TrendLabel 

pub struct TrendLabel { /* private fields */ }

Trend Label — a discrete {−1, 0, +1} classification of the local trend from the sign of the ordinary-least-squares slope over the last period values.

slope = Σ (tᵢ − t̄)(xᵢ − x̄) / Σ (tᵢ − t̄)²      (regress price on bar index)
label = +1 if slope > 0,  −1 if slope < 0,  0 if slope == 0

The sign of the regression slope is scale-invariant — it does not depend on the nominal price level — which makes it a clean, comparable trend state across instruments. +1 marks a rising regression line, −1 a falling one, and 0 a perfectly flat window. It is the discrete companion to LinRegSlope (which returns the continuous slope): use the label when a feature pipeline wants a categorical trend direction and keys any magnitude / dead-band tuning on the raw slope itself.

Each update is O(period): the slope numerator is recomputed from the window. The denominator Σ(tᵢ − t̄)² is strictly positive for period ≥ 2, so the sign is always well-defined.

Example

use wickra_core::{Indicator, TrendLabel};

let mut indicator = TrendLabel::new(10).unwrap();
let mut last = None;
for i in 0..20 {
    last = indicator.update(100.0 + f64::from(i)); // strictly rising
}
assert_eq!(last, Some(1.0));

Implementations

impl TrendLabel

pub fn new(period: usize) -> Result<Self>

Construct a new Trend Label classifier.

Errors

Returns Error::InvalidPeriod if period < 2 — a slope needs at least two points.

pub const fn period(&self) -> usize

Configured period.

Trait Implementations

impl Clone for TrendLabel

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 TrendLabel

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

Formats the value using the given formatter.

impl Indicator for TrendLabel

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, value: 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.