# McGinley Dynamic

`D07-F01-A18` · Technical Indicators → Trend Smoothing · archetype `series-transform` · difficulty 2/5 · verification **verified**

Full page: https://docs.thefintechbuilder.com/technical-indicators/trend-smoothing/mcginley-dynamic/
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 { mcginleyDynamic } from "fintech-algorithms/technical-indicators/trend-smoothing/mcginley-dynamic";
```

## Signature

```ts
mcginleyDynamic(input)
```

Tracks close with McGinley's self-adjusting recursion, dividing the step toward the new close by `k * period * (close / previous) ** 4` so the line accelerates when price runs away from it and coasts when price is near.

## Parameters

| Name | Type | Required | Notes |
| --- | --- | --- | --- |
| `input` | `TopicInput` | yes | `bars` is a non-empty array of OHLCV records with strictly increasing `timestamp`, finite `open`, `high`, `low`, `close` and non-negative `volume`, all sharing one adjustment basis. From `parameters` this topic reads `period`, an integer of at least 2, default 14, and `k`, a finite number of at least 0.000001 that damps the step size, default 0.6. |

## Returns

`TopicResult`

`series` and `latest` carry a single key, `value`. There is no warm-up: the first bar is seeded with its own close, so `ready_at` is 0 and no entry is ever null.

## Warm-up

The first `0 bars` positions are `not applicable`. Unlike the windowed smoothers in this family, the recursion is seeded directly from the first close, so `value` is populated from index 0 and `ready_at` is 0. `period` still controls how fast the line converges, it just does not delay the first print.

## Errors

- When `parameters.k` is not a finite number of at least 0.000001 — throws Error
- When `parameters.period` is not an integer of at least 2 — throws Error
- When `bars` is empty or a bar violates the OHLCV contract — 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
mcginleyDynamic(input)
```

### Returns

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

```json
{
  "topic_id": "D07-F01-A18",
  "title": "McGinley Dynamic",
  "state": "calculated",
  "ready": true,
  "ready_at": 0,
  "series": {
    "value": [
      100,
      100.19828143903013,
      100.49269368385441,
      100.78556845098775,
      101.010298670479,
      101.15287258809037
    ]
  },
  "latest": {
    "value": 103.52627869720108
  },
  "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/trend-smoothing/mcginley-dynamic/
- Implementation source: https://github.com/IslamBaraka90/Fintech-Algorithms-Library/blob/main/src/technical-indicators/trend-smoothing/mcginley-dynamic/impl.ts
- Package on npm: https://www.npmjs.com/package/fintech-algorithms
- Domain index for agents: https://docs.thefintechbuilder.com/technical-indicators/llms.txt