https://github.com/drom/fourier

:wavy_dash: Fourier transform in JavaScript
https://github.com/drom/fourier

fft fourier hacktoberfest

Last synced: 6 months ago
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:wavy_dash: Fourier transform in JavaScript

• Host: GitHub
• URL: https://github.com/drom/fourier
• Owner: drom
• License: mit
• Created: 2015-03-29T07:32:21.000Z (over 10 years ago)
• Default Branch: master
• Last Pushed: 2024-01-27T07:52:30.000Z (over 1 year ago)
• Last Synced: 2025-04-10T11:25:13.168Z (6 months ago)
• Topics: fft, fourier, hacktoberfest
• Language: JavaScript
• Homepage:
• Size: 229 KB
• Stars: 79
• Watchers: 7
• Forks: 10
• Open Issues: 8
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

          


# *Fourier*

[![NPM version](https://img.shields.io/npm/v/fourier.svg)](https://www.npmjs.org/package/fourier)

[![Linux](https://github.com/drom/fourier/actions/workflows/linux.yml/badge.svg)](https://github.com/drom/fourier/actions/workflows/linux.yml)

[![MacOS](https://github.com/drom/fourier/actions/workflows/macos.yml/badge.svg)](https://github.com/drom/fourier/actions/workflows/macos.yml)

[![Windows](https://github.com/drom/fourier/actions/workflows/windows.yml/badge.svg)](https://github.com/drom/fourier/actions/workflows/windows.yml)

Pure JavaScript library discrete transforms, including [Discrete Fourier Transform](http://en.wikipedia.org/wiki/Discrete_Fourier_transform) (DFT); It's fast, inverse, and special forms.

## Use

### Node.js

```

npm i fourier

```

```js

var fourier = require('fourier');

```

### Browser

```html

```

## Functions

### FFT custom

Fast Fourier transform (FFT). Cooley–Tukey algorithm. in-place. Radix-2, Decimation in Time (DIT).

One function for each data type, vector size and coding style

```js

fourier.custom.fft___

```

- data type: `f32` or `f64`

- vector size: `16`, `32`, ... `1048576`

- coding style: 'raw' or `asm`

#### example:

```js

// Init

var stdlib = {

    Math: Math,

    Float32Array: Float32Array,

    Float64Array: Float64Array

};

// Create heap for the fft data and twiddle factors

var heap = fourier.custom.alloc(65536, 3);

// Create instance of FFT runner

var fft_f64_65536_asm_runner = fourier.custom.fft_f64_65536_asm(stdlib, null, heap);

// Init twiddle factors

fft_f64_65536_asm_runner.init();

// Run transformations

fft_f64_65536_asm_runner.transform();

```

### Other

```js

fourier.dft(realArray, imagArray); // ⇒ [realArray, imagArray]

```

$$\large X_k=\sum_{n=0}^{N-1}x_n\cdot e^{-i 2 \pi k n/N}$$

```js

fourier.idft(realArray, imagArray); // ⇒ [realArray, imagArray]

```

$$\large x_n=\frac{1}{N}\sum_{k=0}^{N-1}X_k\cdot e^{i 2 \pi kn/N}$$

## Testing

`npm test`

## License

MIT [LICENSE](https://github.com/drom/fourier/blob/master/LICENSE).