wickra/docs/wiki/indicators/volume/Indicator-Adl.md

ADL

Accumulation/Distribution Line — a cumulative volume-flow line that weights each bar's volume by where its close fell within the range.

Quick reference

Field	Value
Family	Volume
Input type	Candle (uses high, low, close, volume)
Output type	f64
Output range	unbounded (drifts with cumulative volume)
Default parameters	none (no parameters)
Warmup period	1
Interpretation	Running buying/selling pressure; slope and divergence matter.

Formula

MFM_t = ((close − low) − (high − close)) / (high − low)   (money-flow multiplier, −1..+1)
MFV_t = MFM_t · volume_t                                  (money-flow volume)
ADL_t = ADL_{t−1} + MFV_t

The money-flow multiplier asks where in the bar's range did price close? A close on the high gives +1 (full accumulation), on the low −1 (full distribution), in the middle 0. Scaling by volume and running the cumulative total gives a line whose slope reflects sustained buying or selling pressure. A bar with high == low carries no positional information and contributes 0.

Parameters

ADL takes no parameters — Adl::new() in Rust, wickra.ADL() in Python, new ta.ADL() in Node.

Inputs / Outputs

From crates/wickra-core/src/indicators/adl.rs:

impl Indicator for Adl {
    type Input = Candle;
    type Output = f64;
    // update(&mut self, input: Candle) -> Option<f64>
}

ADL is a candle-input indicator: it reads high, low, close and volume. In Python the streaming update accepts a 6-tuple or a dict; the batch helper takes high, low, close, volume numpy arrays. Node and WASM expose update(high, low, close, volume) and the matching batch.

Warmup

Adl::new().warmup_period() == 1. ADL is cumulative — it emits a value from the very first candle.

Edge cases

• Zero-range bar. A bar with high == low contributes 0 to the line (zero_range_bar_contributes_nothing pins this).
• Close at the high. Every bar closing on its high has MFM = +1, so ADL grows by exactly volume each bar (close_at_high_accumulates_full_volume pins this).
• Candle validation. Candle::new rejects invalid bars upstream.
• Reset. adl.reset() returns the running total to 0.

Examples

Rust

use wickra::{BatchExt, Candle, Indicator, Adl};

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let mut adl = Adl::new();
    let out = adl.batch(&[
        Candle::new(8.0, 10.0, 8.0, 10.0, 100.0, 0)?,  // close at high
        Candle::new(10.0, 12.0, 8.0, 9.0, 200.0, 1)?,
    ]);
    println!("{:?}", out);
    Ok(())
}

Output:

[Some(100.0), Some(0.0)]

Bar 1 closes at its high (MFM = +1), adding +100. Bar 2 has MFM = ((9−8)−(12−9))/4 = −0.5, adding −100, so the line returns to 0. This matches the reference_values test in crates/wickra-core/src/indicators/adl.rs.

Python

import numpy as np
import wickra as ta

adl = ta.ADL()
high = np.array([10.0, 12.0])
low = np.array([8.0, 8.0])
close = np.array([10.0, 9.0])
volume = np.array([100.0, 200.0])
print(adl.batch(high, low, close, volume))

Output:

[100.   0.]

Node

const ta = require('wickra');
const adl = new ta.ADL();
console.log(adl.batch([10, 12], [8, 8], [10, 9], [100, 200]));

Output:

[ 100, 0 ]

Interpretation

Adl is read by slope and by divergence, never by absolute level (the total drifts arbitrarily with cumulative volume). A rising ADL confirms that an up-move is backed by accumulation; a falling ADL while price rises is a bearish divergence — the rally is not being bought into. ChaikinOscillator is the standard way to turn the ADL into a bounded, tradeable oscillator.

Common pitfalls

• Reading the absolute value. Only the slope and divergences are meaningful; the level depends on where you started the stream.
• Feeding it scalar prices. It needs the full OHLCV bar.

References

Marc Chaikin's Accumulation/Distribution Line; the money-flow-multiplier formulation here matches the standard definition (StockCharts, TA-Lib's AD).

See also

• Indicator-Obv.md — cumulative signed volume.
• Indicator-ChaikinOscillator.md — an oscillator built on the ADL.
• Indicators-Overview.md — the full taxonomy.