https://github.com/stdlib-js/ndarray-broadcast-array
Broadcast an ndarray to a specified shape.
https://github.com/stdlib-js/ndarray-broadcast-array
array broadcast broadcasting javascript multidimensional ndarray node node-js nodejs reshape stdlib types util utilities utility utils
Last synced: 4 months ago
JSON representation
Broadcast an ndarray to a specified shape.
- Host: GitHub
- URL: https://github.com/stdlib-js/ndarray-broadcast-array
- Owner: stdlib-js
- License: apache-2.0
- Created: 2023-10-02T23:54:38.000Z (over 2 years ago)
- Default Branch: main
- Last Pushed: 2024-08-01T13:24:12.000Z (over 1 year ago)
- Last Synced: 2025-10-05T09:42:22.805Z (7 months ago)
- Topics: array, broadcast, broadcasting, javascript, multidimensional, ndarray, node, node-js, nodejs, reshape, stdlib, types, util, utilities, utility, utils
- Language: JavaScript
- Homepage: https://github.com/stdlib-js/stdlib
- Size: 1.23 MB
- Stars: 1
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- Contributing: CONTRIBUTING.md
- License: LICENSE
- Code of conduct: CODE_OF_CONDUCT.md
- Citation: CITATION.cff
- Security: SECURITY.md
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README
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# broadcastArray
[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url]
> Broadcast an [ndarray][@stdlib/ndarray/ctor] to a specified shape.
## Installation
```bash
npm install @stdlib/ndarray-broadcast-array
```
Alternatively,
- To load the package in a website via a `script` tag without installation and bundlers, use the [ES Module][es-module] available on the [`esm`][esm-url] branch (see [README][esm-readme]).
- If you are using Deno, visit the [`deno`][deno-url] branch (see [README][deno-readme] for usage intructions).
- For use in Observable, or in browser/node environments, use the [Universal Module Definition (UMD)][umd] build available on the [`umd`][umd-url] branch (see [README][umd-readme]).
The [branches.md][branches-url] file summarizes the available branches and displays a diagram illustrating their relationships.
To view installation and usage instructions specific to each branch build, be sure to explicitly navigate to the respective README files on each branch, as linked to above.
## Usage
```javascript
var broadcastArray = require( '@stdlib/ndarray-broadcast-array' );
```
#### broadcastArray( x, shape )
Broadcasts an [ndarray][@stdlib/ndarray/ctor] to a specified `shape`.
```javascript
var array = require( '@stdlib/ndarray-array' );
// Create a 2x2 ndarray:
var x = array( [ [ 1, 2 ], [ 3, 4 ] ] );
// returns
// Broadcast to a 2x2x2 ndarray:
var y = broadcastArray( x, [ 2, 2, 2 ] );
// returns
```
## Notes
- The function throws an error if a provided [ndarray][@stdlib/ndarray/ctor] is [incompatible][@stdlib/ndarray/base/broadcast-shapes] with a provided shape.
- The returned [ndarray][@stdlib/ndarray/ctor] is a **read-only** view on the input [ndarray][@stdlib/ndarray/ctor] data buffer. The view is typically **not** contiguous. As more than one element of a returned view may refer to the same memory location, writing to the input [ndarray][@stdlib/ndarray/ctor] may affect multiple elements. If you need to write to the input [ndarray][@stdlib/ndarray/ctor], copy the input [ndarray][@stdlib/ndarray/ctor] **before** broadcasting.
- The function always returns a new [ndarray][@stdlib/ndarray/ctor] instance even if the input [ndarray][@stdlib/ndarray/ctor] shape and the desired shape are the same.
## Examples
```javascript
var array = require( '@stdlib/ndarray-array' );
var numel = require( '@stdlib/ndarray-base-numel' );
var ind2sub = require( '@stdlib/ndarray-ind2sub' );
var broadcastArray = require( '@stdlib/ndarray-broadcast-array' );
// Create a 2x2 array:
var x = array( [ [ 1, 2 ], [ 3, 4 ] ] );
// returns
// Broadcast the array to 3x2x2:
var y = broadcastArray( x, [ 3, 2, 2 ] );
// returns
// Retrieve the shape:
var sh = y.shape;
// returns [ 3, 2, 2 ]
// Retrieve the number of elements:
var N = numel( sh );
// Loop through the array elements...
var i;
for ( i = 0; i < N; i++ ) {
console.log( 'Y[%s] = %d', ind2sub( sh, i ).join( ', ' ), y.iget( i ) );
}
```
* * *
## See Also
- [`@stdlib/ndarray-array`][@stdlib/ndarray/array]: multidimensional arrays.
- [`@stdlib/ndarray-broadcast-arrays`][@stdlib/ndarray/broadcast-arrays]: broadcast ndarrays to a common shape.
- [`@stdlib/ndarray-ctor`][@stdlib/ndarray/ctor]: multidimensional array constructor.
- [`@stdlib/ndarray-maybe-broadcast-array`][@stdlib/ndarray/maybe-broadcast-array]: broadcast an ndarray to a specified shape if and only if the specified shape differs from the provided ndarray's shape.
* * *
## Notice
This package is part of [stdlib][stdlib], a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.
For more information on the project, filing bug reports and feature requests, and guidance on how to develop [stdlib][stdlib], see the main project [repository][stdlib].
#### Community
[![Chat][chat-image]][chat-url]
---
## License
See [LICENSE][stdlib-license].
## Copyright
Copyright © 2016-2024. The Stdlib [Authors][stdlib-authors].
[npm-image]: http://img.shields.io/npm/v/@stdlib/ndarray-broadcast-array.svg
[npm-url]: https://npmjs.org/package/@stdlib/ndarray-broadcast-array
[test-image]: https://github.com/stdlib-js/ndarray-broadcast-array/actions/workflows/test.yml/badge.svg?branch=main
[test-url]: https://github.com/stdlib-js/ndarray-broadcast-array/actions/workflows/test.yml?query=branch:main
[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/ndarray-broadcast-array/main.svg
[coverage-url]: https://codecov.io/github/stdlib-js/ndarray-broadcast-array?branch=main
[chat-image]: https://img.shields.io/gitter/room/stdlib-js/stdlib.svg
[chat-url]: https://app.gitter.im/#/room/#stdlib-js_stdlib:gitter.im
[stdlib]: https://github.com/stdlib-js/stdlib
[stdlib-authors]: https://github.com/stdlib-js/stdlib/graphs/contributors
[umd]: https://github.com/umdjs/umd
[es-module]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Modules
[deno-url]: https://github.com/stdlib-js/ndarray-broadcast-array/tree/deno
[deno-readme]: https://github.com/stdlib-js/ndarray-broadcast-array/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/ndarray-broadcast-array/tree/umd
[umd-readme]: https://github.com/stdlib-js/ndarray-broadcast-array/blob/umd/README.md
[esm-url]: https://github.com/stdlib-js/ndarray-broadcast-array/tree/esm
[esm-readme]: https://github.com/stdlib-js/ndarray-broadcast-array/blob/esm/README.md
[branches-url]: https://github.com/stdlib-js/ndarray-broadcast-array/blob/main/branches.md
[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/ndarray-broadcast-array/main/LICENSE
[@stdlib/ndarray/ctor]: https://github.com/stdlib-js/ndarray-ctor
[@stdlib/ndarray/base/broadcast-shapes]: https://github.com/stdlib-js/ndarray-base-broadcast-shapes
[@stdlib/ndarray/array]: https://github.com/stdlib-js/ndarray-array
[@stdlib/ndarray/broadcast-arrays]: https://github.com/stdlib-js/ndarray-broadcast-arrays
[@stdlib/ndarray/maybe-broadcast-array]: https://github.com/stdlib-js/ndarray-maybe-broadcast-array