# Positive Volume Index

`D07-F05-A11` · Technical Indicators → Volume Indicators · archetype `series-transform` · difficulty 2/5 · verification **verified**

Full page: https://docs.thefintechbuilder.com/technical-indicators/volume-indicators/positive-volume-index/
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 { positiveVolumeIndex } from "fintech-algorithms/technical-indicators/volume-indicators/positive-volume-index";
```

## Signature

```ts
positiveVolumeIndex(input)
```

Tracks a cumulative index seeded at 1000 that compounds the close-to-close return only on bars whose volume rose against the prior bar.

## Parameters

| Name | Type | Required | Notes |
| --- | --- | --- | --- |
| `input` | `TopicInput` | yes | `bars` needs `timestamp`, `close` and `volume`. This topic reads no parameters of its own; the family reads `period` (default 14), `fast_period` (default 3) and `slow_period` (default 10, minimum `fast_period` + 1) for every volume topic, so a non-integer or out-of-range value throws even when this topic ignores it. |

## Returns

`TopicResult`

`series` holds a single `value`, and `latest` its last element. The first bar is 1000; each later bar multiplies the running level by `close / prior close` when volume rose, and otherwise carries the previous level forward unchanged (as it also does when the prior close is 0). No element is ever null, so there is no warm-up.

## Warm-up

The first `none` positions are `1000 on the first bar`. `ready_at` is 0. The series is a level, not a signal, so the seed is a real value rather than a placeholder.

## Errors

- When a bar carries a negative `volume` — throws Error
- When a `close` is not a finite number — throws Error
- When two bars share a timestamp, or the bars are out of order — 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
positiveVolumeIndex(input)
```

### Returns

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

```json
{
  "topic_id": "D07-F05-A11",
  "title": "Positive Volume Index",
  "state": "calculated",
  "ready": true,
  "ready_at": 0,
  "series": {
    "value": [1000, 1017.8791214, 1029.549389, 1032.3228269, 1028.3130013, 1022.6872597]
  },
  "latest": {
    "value": 1008.9457679026209
  },
  "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/volume-indicators/positive-volume-index/
- Implementation source: https://github.com/IslamBaraka90/Fintech-Algorithms-Library/blob/main/src/technical-indicators/volume-indicators/positive-volume-index/impl.ts
- Package on npm: https://www.npmjs.com/package/fintech-algorithms
- Domain index for agents: https://docs.thefintechbuilder.com/technical-indicators/llms.txt