https://github.com/drom/fourier
:wavy_dash: Fourier transform in JavaScript
https://github.com/drom/fourier
fft fourier hacktoberfest
Last synced: about 1 year ago
JSON representation
: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 (about 11 years ago)
- Default Branch: master
- Last Pushed: 2024-01-27T07:52:30.000Z (over 2 years ago)
- Last Synced: 2025-04-10T11:25:13.168Z (about 1 year 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
Awesome Lists containing this project
README
# *Fourier*
[](https://www.npmjs.org/package/fourier)
[](https://github.com/drom/fourier/actions/workflows/linux.yml)
[](https://github.com/drom/fourier/actions/workflows/macos.yml)
[](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).