Absolute Price Oscillator (APO)

Summary

Absolute Price Oscillator: the difference between a fast and a slow moving average of the input, in price units. Measures short- vs long-term momentum. Positive when fast MA > slow MA (upward momentum); negative otherwise.

Chart

Reference data (CSV) · Chart (SVG)

Chart metadata i

Outputs

• outReal: line · zero · positive · negative

Formula

$APO = MA_{fast}(inReal) - MA_{slow}(inReal)$, both MAs of type optInMAType

The standard form is exponential — APO with EMA and periods 12/26 is the fast-minus-slow EMA construction underlying the MACD (in price units). optInMAType therefore defaults to EMA — the moving average Gerald Appel used for the original MACD; pass another type (e.g. TA_MAType_SMA) to override.

Notes

• optInMAType applies to both the fast and slow moving average. TA_MAType_MAMA ignores its period argument, so with optInMAType = TA_MAType_MAMA the fast and slow MAs are identical and the output is zero at every bar.
• If the slow period is set smaller than the fast period, the two are swapped, as in MACD.

Inputs

• inReal — Source data series

Outputs

• outReal — Fast MA minus slow MA

Parameters

Parameter	Type	Default	Accepted values	Description
optInFastPeriod	integer	12	2–100000	Period of the fast moving average
optInSlowPeriod	integer	26	2–100000	Period of the slow moving average
optInMAType	MAType	EMA (1)	any MAType	Moving-average type used for both MAs

MAType values: 0 SMA · 1 EMA · 2 WMA · 3 DEMA · 4 TEMA · 5 TRIMA · 6 KAMA · 7 MAMA · 8 T3 · 9 HMA · 10 DISABLED · 11 DEFAULT · 12 ZLEMA · 13 RMA · 14 VIDYA · 15 ALMA

Properties

Numerical Stability: Depends on MA Type — This function's default, EMA, has an initial unstable period.

☐ Overlap Input
✅ Independent Y-Axis i
☐ Candlestick
☐ Display Shift

☐ Can Output NaN or ±Inf
☐ Identity at Period 1
☐ Uses Transcendental
☐ Input Must Be Positive

Example

C

#include <stdio.h>
#include <ta_libc.h>

int n = 252;
double series[252]; /* your data, oldest first */
double out[252];
int outBegIdx, outNBElement;

TA_Initialize();
TA_APO( 0, n - 1, series, 12, 26, TA_MAType_EMA, &outBegIdx, &outNBElement, out );
printf( "%d values from bar %d; last out = %f\n", outNBElement, outBegIdx, out[outNBElement - 1] );

Rust

use ta_lib::{Core, MAType};

let series = vec![0.0; 252]; // your data, oldest first
let mut out = vec![0.0; 252];

let core = Core::new();
let range = core.apo(0, series.len() - 1, &series, 12, 26, MAType::EMA, &mut out)?;
println!("{} values from bar {}; last out = {}", range.count, range.beg_idx, out[range.count - 1]);

Java

import io.github.talib.Core;
import io.github.talib.MAType;
import io.github.talib.OutRange;

double[] series = new double[252]; // your data, oldest first
double[] out = new double[252];

Core core = Core.DEFAULT;
OutRange r = core.apo(0, series.length - 1, series, 12, 26, MAType.EMA, out);
System.out.println(r.count() + " values from bar " + r.begIdx() + "; last out = " + out[r.count() - 1]);

C#

using System;
using TALib;

var series = new double[252]; // your data, oldest first
var outReal = new double[252];

var core = Core.Default;
OutRange r = core.Apo(0, series.Length - 1, series, 12, 26, MAType.EMA, outReal);
Console.WriteLine($"{r.Count} values from bar {r.BegIdx}; last outReal = {outReal[r.Count - 1]}");

TypeScript

import { MAType, apo } from 'ta-lib';

const series = new Float64Array(252); // your data, oldest first

const { begIdx, values } = apo(series, {
  fastPeriod: 12,
  slowPeriod: 26,
  maType: MAType.EMA,
});
console.log(values.length + ' values from bar ' + begIdx + '; last values = ' + values[values.length - 1]);

Implementation

Added in 0.4.0.

TA-Lib Definition: apo.c · apo.yaml

Native	File
C	ta_APO.c
Rust	apo.rs
Java	Core_APO.java
C#	Core_APO.cs
TypeScript	apo.ts

Python: talib.APO, see ta-lib-python.

TA-Lib is also available for R and more using a wrapper.

Aliases

Absolute Price Oscillator

See Also

PPO · MACD · MA · EMA · SMA

References

• Gerald Appel, creator of the MACD (introduced 1979 in his Systems and Forecasts newsletter). The APO is the same fast-minus-slow moving-average oscillator in price units; with exponential moving averages and periods 12/26 it is the oscillator underlying the MACD line. Appel's original definition uses exponential moving averages.