AbsoluteBreadthIndex

The Absolute Breadth Index — the magnitude of net advancing issues, |advancers - decliners|. It ignores direction and measures only how decisively the universe moved — a "market thermometer".

Quick reference

Item	Value
Family	Market Breadth
Input type	CrossSection — the per-symbol state of the whole universe
Output type	f64 (≥ 0)
Output range	0..=N for a universe of N symbols
Default parameters	none
Warmup period	1
Interpretation	Breadth magnitude / activity

Formula

abi = |advancers - decliners|   # per tick, by sign of each member's change

The ABI discards the sign of net breadth and keeps only its magnitude: a high reading means the universe moved decisively one way or the other (high internal activity), a low reading means advances and declines were nearly balanced (a quiet, directionless market). Stateless per tick and O(universe size). See crates/wickra-core/src/indicators/absolute_breadth_index.rs.

Parameters

None. Construct with AbsoluteBreadthIndex::new().

Parameter	Type	Default	Source
—	—	—	None.

Inputs / Outputs

Indicator<Input = CrossSection, Output = f64>:

use wickra::{AbsoluteBreadthIndex, CrossSection, Indicator};

const _: fn(&mut AbsoluteBreadthIndex, CrossSection) -> Option<f64> =
    <AbsoluteBreadthIndex as Indicator>::update;

The bindings pass a tick as four equal-length parallel arrays:

• Python: update(change, volume, new_high, new_low); batch(...) returns a 1-D ndarray.
• Node: update(change, volume, newHigh, newLow); batch returns number[].
• WASM: update(change, volume, newHigh, newLow) only; flag arrays are numeric.

Warmup

warmup_period() == 1; defined from the first tick (tests accessors_and_metadata, magnitude_ignores_direction).

Edge cases

• Direction-blind. (2 up, 5 down) and (5 up, 2 down) both yield 3.0 (test magnitude_ignores_direction).
• Balanced universe. Equal advancers and decliners yield 0.0 (test balanced_universe_yields_zero).
• Reset. reset() returns the indicator to not-ready (test reset_clears_state).
• Invalid / empty universe. Rejected at construction by CrossSection::new.

Examples

Rust

use wickra::{AbsoluteBreadthIndex, CrossSection, Indicator, Member};

let mut abi = AbsoluteBreadthIndex::new();
// 2 advancers, 5 decliners -> |2 - 5| = 3.
let tick = CrossSection::new(
    vec![
        Member::new(1.0, 10.0, false, false),
        Member::new(1.0, 10.0, false, false),
        Member::new(-1.0, 10.0, false, false),
        Member::new(-1.0, 10.0, false, false),
        Member::new(-1.0, 10.0, false, false),
        Member::new(-1.0, 10.0, false, false),
        Member::new(-1.0, 10.0, false, false),
    ],
    0,
)?;
assert_eq!(abi.update(tick), Some(3.0));

Python

import wickra as ta

abi = ta.AbsoluteBreadthIndex()
change = [1.0, 1.0, -1.0, -1.0, -1.0]
print(abi.update(change, [10.0] * 5, [False] * 5, [False] * 5))
# 1.0   (|2 - 3|)

Node

const { AbsoluteBreadthIndex } = require('wickra');

const abi = new AbsoluteBreadthIndex();
const flags = [false, false, false, false, false];
console.log(abi.update([1, 1, -1, -1, -1], [10, 10, 10, 10, 10], flags, flags));
// 1

Streaming

import wickra as ta

abi = ta.AbsoluteBreadthIndex()
print(abi.update([1.0, 1.0, -1.0, -1.0, -1.0], [10.0] * 5, [False] * 5, [False] * 5))  # 1.0
print(abi.update([1.0, 1.0, 1.0, -1.0, -1.0], [10.0] * 5, [False] * 5, [False] * 5))   # 1.0 (same magnitude)

Interpretation

The ABI is read as a volatility/activity gauge rather than a directional one.

1. High readings. Strong internal divergence — the market is "agitated", which often clusters near turning points.
2. Low readings. A balanced, quiet tape with little net conviction.
3. Smoothing. Often viewed through a moving average and compared to its own history; the raw value depends on universe size.

Common pitfalls

• No direction. The ABI cannot tell you which way the market moved — pair it with TickIndex or the A/D Line for direction.
• Universe-dependent. The scale grows with the universe; compare only within a fixed universe.

References

• Fosback, N. (1976). Stock Market Logic — Absolute Breadth Index.

See also

• Indicator-TickIndex — the signed net of the same counts.
• Indicators-Overview — the full taxonomy.