# Absolute Price Oscillator

`D07-F03-A09` · Technical Indicators → Momentum · archetype `series-transform` · difficulty 2/5 · verification **verified**

Full page: https://docs.thefintechbuilder.com/technical-indicators/momentum/absolute-price-oscillator/
Agent skill: `npx skills add IslamBaraka90/Fintech-Algorithms-Library` — https://docs.thefintechbuilder.com/guides/agent-skill/

## Install and import

```bash
npm install fintech-algorithms
```

```ts
import { absolutePriceOscillator } from "fintech-algorithms/technical-indicators/momentum/absolute-price-oscillator";
```

## Signature

```ts
absolutePriceOscillator(input)
```

Subtracts a slow EMA of `close` from a fast EMA of `close`, leaving the momentum spread in price units rather than as a percentage.

## Parameters

| Name | Type | Required | Notes |
| --- | --- | --- | --- |
| `input` | `TopicInput` | yes | `bars` is a chronological array of OHLCV rows, each with a non-empty `timestamp` plus finite `open`, `high`, `low`, `close` and `volume`. From `parameters` this topic reads `fast_period` (integer >= 2, default 5) and `slow_period` (integer >= `fast_period` + 1, default 34). `period` (default 14) is validated by the shared momentum preamble but is not used here. |

## Returns

`TopicResult`

`series` and `latest` carry one key, `value`, holding the fast EMA minus the slow EMA at each bar. Both EMAs seed from the simple average of their first full window, so the series opens with a null warm-up prefix.

## Warm-up

The first `slow_period - 1 bars (33 with the default 34)` positions are `null`. `value` stays null until the slow EMA is seeded, which happens at index `slow_period - 1`; `ready_at` is 33 on the canonical fixture.

## Errors

- When `slow_period` is not an integer greater than `fast_period` — throws Error
- When a bar's `high` is below its `open`, `close`, or `low` — throws Error

## Complexity

Time `O(n)`, space `O(n)`.

## Worked example

Captured by running this function on the input its own test provides. Real output of real code — but not asserted against a published figure.

### Input

`input`:

```json
{
  "bars": [
    {
      "timestamp": "2024-01-02",
      "basis": "synthetic-unadjusted",
      "open": 100,
      "high": 101.45,
      "low": 98.695,
      "close": 100,
      "volume": 750000,
      "benchmark": 200
    },
    {
      "timestamp": "2024-01-03",
      "basis": "synthetic-unadjusted",
      "open": 101.49111452,
      "high": 103.38381693,
      "low": 100.05480022,
      "close": 101.78791214,
      "volume": 795117,
      "benchmark": 200.56326135
    },
    {
      "timestamp": "2024-01-04",
      "basis": "synthetic-unadjusted",
      "open": 102.45519048,
      "high": 104.6701838,
      "low": 100.91147007,
      "close": 102.9549389,
      "volume": 840234,
      "benchmark": 201.11020913
    }
  ],
  "parameters": {}
}
```

### Call

```ts
absolutePriceOscillator(input)
```

### Returns

object with 9 fields: topic_id, title, state, ready, ready_at, series, latest, parameters, …

```json
{
  "topic_id": "D07-F03-A09",
  "title": "Absolute Price Oscillator",
  "state": "calculated",
  "ready": true,
  "ready_at": 33,
  "series": {
    "value": [null, null, null, null, null, null]
  },
  "latest": {
    "value": -2.0125312416213603
  },
  "parameters": {},
  "diagnostics": {
    "causal": true,
    "input_count": 96
  }
}
```

## Verification and provenance

Tier: **verified** (via E).

The worked example below is the figure published in this algorithm's article, replayed and asserted by the test suite on every build. The arithmetic cannot drift without the build failing.

Both tiers guarantee the signature. Full explanation: https://docs.thefintechbuilder.com/guides/verification/

Generated from the docs.json payload shipped inside fintech-algorithms@0.13.0.
The signature and parameter list are checked against the compiled implementation at build time,
so a description that contradicts the code fails the build rather than reaching this file.

## Links

- Article (how it works, step by step): https://thefintechbuilder.com/technical-indicators/momentum/absolute-price-oscillator/
- Implementation source: https://github.com/IslamBaraka90/Fintech-Algorithms-Library/blob/main/src/technical-indicators/momentum/absolute-price-oscillator/impl.ts
- Package on npm: https://www.npmjs.com/package/fintech-algorithms
- Domain index for agents: https://docs.thefintechbuilder.com/technical-indicators/llms.txt