wickra/docs/wiki/indicators/momentum/Indicator-BalanceOfPower.md

BalanceOfPower

Balance of Power (BOP) — where the bar closed within its range relative to where it opened.

Quick reference

Field	Value
Family	Price Oscillators
Input type	Candle (uses open, high, low, close)
Output type	f64
Output range	[−1, +1]
Default parameters	none (no parameters)
Warmup period	1
Interpretation	Intrabar buyer/seller control; +1 buyers, −1 sellers.

Formula

BOP = (close − open) / (high − low)

Balance of Power asks a single question per bar: did buyers or sellers win it? A bar that opened on its low and closed on its high scores +1 (buyers in total control); the mirror image scores −1. It is a stateless per-bar reading. A zero-range bar carries no information and yields 0.

Parameters

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

Inputs / Outputs

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

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

BalanceOfPower is a candle-input indicator that reads all four of open, high, low, close. Python's streaming update accepts a 6-tuple or a dict; the batch helper takes open, high, low, close numpy arrays. Node and WASM expose update(open, high, low, close) and the matching batch.

Warmup

BalanceOfPower::new().warmup_period() == 1. It is a stateless per-bar transform — it emits a value from the very first candle.

Edge cases

• Zero-range bar. high == low yields 0 instead of dividing by zero.
• Close on high, open on low. Scores exactly +1.
• Reset. bop.reset() only clears the is_ready flag.

Examples

Rust

use wickra::{Candle, Indicator, BalanceOfPower};

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let mut bop = BalanceOfPower::new();
    // open 10, high 14, low 10, close 12 -> (12 - 10) / (14 - 10) = 0.5.
    let v = bop.update(Candle::new(10.0, 14.0, 10.0, 12.0, 1.0, 0)?);
    println!("{:?}", v);
    Ok(())
}

Output:

Some(0.5)

Python

import numpy as np
import wickra as ta

bop = ta.BalanceOfPower()
print(bop.batch(
    np.array([10.0]), np.array([14.0]), np.array([10.0]), np.array([12.0])
))

Output:

[0.5]

Node

const ta = require('wickra');
const bop = new ta.BalanceOfPower();
console.log(bop.batch([10], [14], [10], [12]));

Output:

[ 0.5 ]

Interpretation

A BOP holding above zero says buyers are consistently winning the bars — a healthy uptrend; below zero is the seller's mirror. Because the raw per-bar value is noisy, it is commonly smoothed with a short moving average before trading the zero-line crossings, or read for divergence against price.

Common pitfalls

• Using the raw value as a trend signal. Per-bar BOP whipsaws; smooth it.
• Feeding it scalar prices. It needs the full OHLC bar — including open.

References

Balance of Power, popularised by Igor Livshin; the (close − open) / (high − low) definition is the standard one.

See also

• Indicator-AwesomeOscillator.md — another Bill Williams-era price oscillator.
• Indicators-Overview.md — the full taxonomy.