https://github.com/howion/lambert-w-function

A JavaScript implementation for the Lambert W Function on the principal branch.
https://github.com/howion/lambert-w-function

javascript lambert library math mathematics typescript

Last synced: about 1 year ago
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A JavaScript implementation for the Lambert W Function on the principal branch.

• Host: GitHub
• URL: https://github.com/howion/lambert-w-function
• Owner: howion
• License: mit
• Created: 2019-07-16T12:36:03.000Z (almost 7 years ago)
• Default Branch: master
• Last Pushed: 2022-04-10T16:34:55.000Z (about 4 years ago)
• Last Synced: 2025-04-20T05:17:56.907Z (about 1 year ago)
• Topics: javascript, lambert, library, math, mathematics, typescript
• Language: TypeScript
• Homepage:
• Size: 48.8 KB
• Stars: 3
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

          
# lambert-w-function

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This is a JavaScript implementation for the [**Lambert W Function**](https://en.wikipedia.org/wiki/Lambert_W_function), which is also known as **Omega Function**, on the principal branch `W_0`.

Please note that this library **does not** support **complex** numbers and only supports the **principal branch**.

## Installation

From [**npm**](https://www.npmjs.com/package/lambert-w-function) via npm

```bash

npm install lambert-w-function

```

or via yarn

```bash

yarn add lambert-w-function

```

## Import

For CommonJS

```js

const {

    lambertW0, // same as lambertW0_IaconoBoyd

    lambertW0_IaconoBoyd,

    lambertW0Log, // same as lambertW0Log_xmodar

    lambertW0Log_xmodar,

    lambertW0_SimpleIteration_LT_E,

    lambertW0_SimpleIteration_GT_E,

    W0_LIMIT_POINT

} = require('lambert-w-function')

```

otherwise

```js

import { ... } from 'lambert-w-function'

```

## Usage / Documentation

```js

// A good approximation with a maximum relative error 5E-3

// Same as lambertW0Log(x) if is_x_log set to true.

// -

// See: https://gist.github.com/xmodar/baa392fc2bec447d10c2c20bbdcaf687

// See: https://link.springer.com/content/pdf/10.1007/s10444-017-9530-3.pdf

lambertW0(x: number, is_x_log = false): number

// Computes W(y) where y of the form log(x)

// -

// See: https://gist.github.com/xmodar/baa392fc2bec447d10c2c20bbdcaf687

lambertW0Log(logX: number): number

// Approximates W(X) with a straightforward algoritm for x <= E (respectively

// x > E) but it is highly recommended to use lambertW0 instead.

// -

// See: https://doi.org/10.1145%2F258726.258783

lambertW0_SimpleIteration_LT_E(x: number, iterations = 10): number

lambertW0_SimpleIteration_GT_E(x: number, iterations = 10): number

```

You can check out the [**Desmos Demo**](https://www.desmos.com/calculator/rhbaludwth) to preview simple iteration algorithm up to 20 iterations.

## License

This project is licensed under the [**MIT**](https://github.com/howion/lambert-w-function/blob/master/LICENSE) license so that you can just do whatever you want with it.