npm package: @stdlib/ndarray-base-broadcast-arrays
Description: Broadcast ndarrays to a common shape.
Author: The Stdlib Authors
Latest version: 0.2.3

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# broadcastArrays

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> Broadcast [ndarrays][@stdlib/ndarray/base/ctor] to a common shape.

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<section class="intro">

</section>

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<!-- Package usage documentation. -->

<section class="installation">

## Installation

```bash
npm install @stdlib/ndarray-base-broadcast-arrays
```

</section>

<section class="usage">

## Usage

```javascript
var broadcastArrays = require( '@stdlib/ndarray-base-broadcast-arrays' );
```

#### broadcastArrays( arrays )

Broadcasts a list of [ndarrays][@stdlib/ndarray/base/ctor] to a common shape.

```javascript
var array = require( '@stdlib/ndarray-array' );
var zeros = require( '@stdlib/ndarray-zeros' );

// Create a 2x2 ndarray:
var x = array( [ [ 1, 2 ], [ 3, 4 ] ] );
// returns <ndarray>

// Create a 2x2x2 ndarray:
var y = zeros( [ 2, 2, 2 ] );
// returns <ndarray>

// Broadcast to a common shape:
var out = broadcastArrays( [ x, y ] );
// returns [ <ndarray>, <ndarray> ]
```

</section>

<!-- /.usage -->

<!-- Package usage notes. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->

<section class="notes">

## Notes

-   The function throws an error if provided [broadcast-incompatible][@stdlib/ndarray/base/broadcast-shapes] ndarrays.
-   Returned [ndarrays][@stdlib/ndarray/base/ctor] are views on their respective underlying data buffers. The views are typically **not** contiguous. As more than one element of a returned view may refer to the same memory location, writing to a view may affect multiple elements. If you need to write to a returned [ndarray][@stdlib/ndarray/base/ctor], copy the [ndarray][@stdlib/ndarray/base/ctor] **before** performing operations which may mutate elements.
-   Returned [ndarrays][@stdlib/ndarray/base/ctor] are "base" [ndarrays][@stdlib/ndarray/base/ctor], and, thus, the returned [ndarrays][@stdlib/ndarray/base/ctor] do not perform bounds checking or afford any of the guarantees of the non-base [ndarray][@stdlib/ndarray/ctor] constructor. The primary intent of this function is to broadcast ndarray-like objects within internal implementations and to do so with minimal overhead.
-   The function always returns new [ndarray][@stdlib/ndarray/base/ctor] instances even if an input [ndarray][@stdlib/ndarray/base/ctor] shape and the broadcasted shape are the same.

</section>

<!-- /.notes -->

<!-- Package usage examples. -->

<section class="examples">

## Examples

<!-- eslint no-undef: "error" -->

```javascript
var array = require( '@stdlib/ndarray-array' );
var zeros = require( '@stdlib/ndarray-zeros' );
var numel = require( '@stdlib/ndarray-base-numel' );
var ind2sub = require( '@stdlib/ndarray-ind2sub' );
var broadcastArrays = require( '@stdlib/ndarray-base-broadcast-arrays' );

// Create a 2x2 array:
var x = array( [ [ 1, 2 ], [ 3, 4 ] ] );
// returns <ndarray>

// Create a 3x2x2 array:
var y = zeros( [ 3, 2, 2 ] );
// returns <ndarray>

// Broadcast the arrays to a common shape:
var out = broadcastArrays( [ x, y ] );
// returns [ <ndarray>, <ndarray> ]

// Retrieve the common shape:
var sh = out[ 0 ].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( 'X[%s] = %d', ind2sub( sh, i ).join( ', ' ), out[ 0 ].iget( i ) );
}
```

</section>

<!-- /.examples -->

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<section class="references">

</section>

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* * *

## 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].

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## License

See [LICENSE][stdlib-license].


## Copyright

Copyright &copy; 2016-2026. The Stdlib [Authors][stdlib-authors].

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