Struct LadderBottom 

pub struct LadderBottom { /* private fields */ }

Ladder Bottom — a 5-bar bullish reversal. Three long black candles step the market down like rungs of a ladder, a fourth black candle finally shows an upper shadow (the first sign of buying), and a white candle then gaps up into its body and closes above the fourth bar’s high to confirm the turn (Nison; TA-Lib CDLLADDERBOTTOM).

bar1, bar2, bar3 black, with consecutively lower opens AND closes
bar4 black with an upper shadow         (high4 > open4)
bar5 white, opens above bar4's body      (open5 > open4)
     and closes above bar4's high          (close5 > high4)

Output is +1.0 when the pattern completes and 0.0 otherwise. Ladder Bottom is a single-direction (bullish-only) reversal, so it never emits −1.0. The first four bars always return 0.0 because the five-bar window is not yet filled. Pattern-shape check only — no trend filter is applied; combine with a trend indicator for actionable signals.

Signed ±1 encoding

This detector emits the uniform candlestick sign convention shared across the pattern family — +1.0 bullish, 0.0 no pattern — so it drops straight into a machine-learning feature matrix as a single dimension.

Example

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

let mut indicator = LadderBottom::new();
indicator.update(Candle::new(20.0, 20.1, 17.9, 18.0, 1.0, 0).unwrap());
indicator.update(Candle::new(18.0, 18.1, 15.9, 16.0, 1.0, 1).unwrap());
indicator.update(Candle::new(16.0, 16.1, 13.9, 14.0, 1.0, 2).unwrap());
indicator.update(Candle::new(14.0, 15.0, 12.4, 12.5, 1.0, 3).unwrap());
let out = indicator
    .update(Candle::new(15.0, 17.1, 14.9, 17.0, 1.0, 4).unwrap());
assert_eq!(out, Some(1.0));

Implementations

impl LadderBottom

pub const fn new() -> Self

Construct a new Ladder Bottom detector.

Trait Implementations

impl Clone for LadderBottom

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 LadderBottom

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

Formats the value using the given formatter.

impl Default for LadderBottom

fn default() -> Self

Returns the “default value” for a type.

impl Indicator for LadderBottom

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 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.