Broadcast an ndarray to a specified shape.
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> Broadcast an [ndarray][@stdlib/ndarray/base/ctor] to a specified shape.
``bash`
npm install @stdlib/ndarray-base-broadcast-array
`javascript`
var broadcastArray = require( '@stdlib/ndarray-base-broadcast-array' );
#### broadcastArray( arr, shape )
Broadcasts an [ndarray][@stdlib/ndarray/base/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
`
- The function throws an error if a provided [ndarray][@stdlib/ndarray/base/ctor] is [incompatible][@stdlib/ndarray/base/broadcast-shapes] with a provided shape.
- The returned [ndarray][@stdlib/ndarray/base/ctor] is a view on the input [ndarray][@stdlib/ndarray/base/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 view may affect multiple elements. If you need to write to the returned [ndarray][@stdlib/ndarray/base/ctor], copy the [ndarray][@stdlib/ndarray/base/ctor] before performing operations which may mutate elements.
- The returned [ndarray][@stdlib/ndarray/base/ctor] is a "base" [ndarray][@stdlib/ndarray/base/ctor], and, thus, the returned [ndarray][@stdlib/ndarray/base/ctor] does 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 an ndarray-like object within internal implementations and to do so with minimal overhead.
- The function always returns a new [ndarray][@stdlib/ndarray/base/ctor] instance even if the input [ndarray][@stdlib/ndarray/base/ctor] shape and the desired shape are the same.
`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-base-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 sub;
var v;
var i;
for ( i = 0; i < N; i++ ) {
v = y.iget( i );
sub = ind2sub( sh, i );
console.log( 'Y[%s] = %d', sub.join( ', ' ), v );
}
`
*
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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