# Regression Channel

`D07-F07-A05` · Technical Indicators → Bands, Envelopes, and Squeezes · archetype `series-transform` · difficulty 2/5 · verification **verified**

Full page: https://docs.thefintechbuilder.com/technical-indicators/bands-envelopes-and-squeezes/regression-channel/
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 { regressionChannel } from "fintech-algorithms/technical-indicators/bands-envelopes-and-squeezes/regression-channel";
```

## Signature

```ts
regressionChannel(input)
```

Regression Channel: the end point of a rolling least-squares fit of close over `period` bars, with bands `multiplier` root-mean-square residuals above and below that fitted point.

## Parameters

| Name | Type | Required | Notes |
| --- | --- | --- | --- |
| `input` | `TopicInput` | yes | `bars` is the required OHLCV array -- each bar carries `timestamp`, `open`, `high`, `low`, `close`, `volume` and an optional `basis`, strictly ordered by timestamp. From `parameters` this topic reads `period` (default 20, integer >= 2), the regression window, and `multiplier` (default 2, a finite number >= 0), the channel half-width in residual units. |

## Returns

`TopicResult`

`series` holds `center`, the fitted close at the end of each window, plus `upper` and `lower`; `latest` carries the last of each. All three share a warm-up of `period - 1` leading nulls, so `ready_at` is 19 at the default period.

## Warm-up

The first ``period - 1` bars (19 at the default period)` positions are `null`. The fit is recomputed from scratch on each full window, so nothing is emitted until `period` closes exist. The channel does not extend or anchor across windows.

## Errors

- When `parameters.period` is not an integer >= 2 — throws Error
- When `parameters.multiplier` is not a finite number, or is negative — throws Error
- When a bar is missing open, high, low, close, or volume, or one of them is not a finite number — throws Error

## Complexity

Time `O(n * period)`, 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
regressionChannel(input)
```

### Returns

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

```json
{
  "topic_id": "D07-F07-A05",
  "title": "Regression Channel",
  "state": "calculated",
  "ready": true,
  "ready_at": 19,
  "series": {
    "center": [null, null, null, null, null, null],
    "upper": [null, null, null, null, null, null],
    "lower": [null, null, null, null, null, null]
  },
  "latest": {
    "center": 103.97453763199998,
    "upper": 108.29510693120406,
    "lower": 99.6539683327959
  },
  "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/bands-envelopes-and-squeezes/regression-channel/
- Implementation source: https://github.com/IslamBaraka90/Fintech-Algorithms-Library/blob/main/src/technical-indicators/bands-envelopes-and-squeezes/regression-channel/impl.ts
- Package on npm: https://www.npmjs.com/package/fintech-algorithms
- Domain index for agents: https://docs.thefintechbuilder.com/technical-indicators/llms.txt