# Ease of Movement

`D07-F05-A12` · Technical Indicators → Volume Indicators · archetype `series-transform` · difficulty 2/5 · verification **verified**

Full page: https://docs.thefintechbuilder.com/technical-indicators/volume-indicators/ease-of-movement/
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 { easeOfMovement } from "fintech-algorithms/technical-indicators/volume-indicators/ease-of-movement";
```

## Signature

```ts
easeOfMovement(input)
```

Divides the typical-price change by a box ratio built from scaled volume over the bar range, then smooths that raw reading with a simple moving average.

## Parameters

| Name | Type | Required | Notes |
| --- | --- | --- | --- |
| `input` | `TopicInput` | yes | `bars` needs `timestamp`, `high`, `low`, `close` and `volume`. From `parameters` this topic reads `volume_scale` (default 1000000, a finite number of at least 0.000001) and `period` (default 14, an integer of at least 2). |

## Returns

`TopicResult`

`series` holds `raw`, the unsmoothed reading, and `value`, its simple moving average over `period`. `latest` carries the last element of each. `raw` is null on the first bar and on any bar whose `high` equals its `low` or whose volume is 0; `value` needs a full window of non-null `raw`, so it starts later than `raw`. Both warm-ups are described below.

## Warm-up

The first `1 bar for `raw`; `period` bars for `value` (index 14 with the defaults)` positions are `null`. `ready_at` is 1, driven by `raw`. Because a null inside the window restarts the average, any flat or zero-volume bar pushes `value` out by a further `period` bars.

## Errors

- When `volume_scale` is below 0.000001 or not a finite number — throws Error
- When `period` is not an integer of at least 2 — throws Error
- When a bar carries a negative `volume` — 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
easeOfMovement(input)
```

### Returns

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

```json
{
  "topic_id": "D07-F05-A12",
  "title": "Ease of Movement",
  "state": "calculated",
  "ready": true,
  "ready_at": 1,
  "series": {
    "raw": [
      null,
      7.09182670339273,
      4.935760375263474,
      1.1777185136470167,
      -1.4745208573506723,
      -1.699726591438122
    ],
    "value": [null, null, null, null, null, null]
  },
  "latest": {
    "raw": -3.4562255141040934,
    "value": -0.7167616272036208
  },
  "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/ease-of-movement/
- Implementation source: https://github.com/IslamBaraka90/Fintech-Algorithms-Library/blob/main/src/technical-indicators/volume-indicators/ease-of-movement/impl.ts
- Package on npm: https://www.npmjs.com/package/fintech-algorithms
- Domain index for agents: https://docs.thefintechbuilder.com/technical-indicators/llms.txt