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base/broadcast-arrays/README.md

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+<!--
+
+@license Apache-2.0
+
+Copyright (c) 2023 The Stdlib Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+   http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+
+-->
+
+# broadcastArrays
+
+> Broadcast [ndarrays][@stdlib/ndarray/base/ctor] to a common shape.
+
+<!-- Section to include introductory text. Make sure to keep an empty line after the intro `section` element and another before the `/section` close. -->
+
+<section class="intro">
+
+</section>
+
+<!-- /.intro -->
+
+<!-- Package usage documentation. -->
+
+<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 sub;
+var v;
+var i;
+for ( i = 0; i < N; i++ ) {
+    v = out[ 0 ].iget( i );
+    sub = ind2sub( sh, i );
+    console.log( 'X[%s] = %d', sub.join( ', ' ), v );
+}
+```
+
+</section>
+
+<!-- /.examples -->
+
+<!-- Section to include cited references. If references are included, add a horizontal rule *before* the section. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
+
+<section class="references">
+
+</section>
+
+<!-- /.references -->
+
+<!-- Section for related `stdlib` packages. Do not manually edit this section, as it is automatically populated. -->
+
+<section class="related">
+
+</section>
+
+<!-- /.related -->
+
+<!-- Section for all links. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
+
+<section class="links">
+
+[@stdlib/ndarray/ctor]: https://github.com/stdlib-js/ndarray/tree/main/ctor
+
+[@stdlib/ndarray/base/ctor]: https://github.com/stdlib-js/ndarray/tree/main/base/ctor
+
+[@stdlib/ndarray/base/broadcast-shapes]: https://github.com/stdlib-js/ndarray/tree/main/base/broadcast-shapes
+
+</section>
+
+<!-- /.links -->

base/broadcast-arrays/benchmark/benchmark.js

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+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2023 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+'use strict';
+
+// MODULES //
+
+var bench = require( '@stdlib/bench' );
+var Float64Array = require( '@stdlib/array/float64' );
+var ndarrayBase = require( './../../../base/ctor' );
+var ndarray = require( './../../../ctor' );
+var zeros = require( './../../../base/zeros' );
+var isndarrayLike = require( '@stdlib/assert/is-ndarray-like' );
+var pkg = require( './../package.json' ).name;
+var broadcastArrays = require( './../lib' );
+
+
+// MAIN //
+
+bench( pkg+'::base_ndarray,2d:num_arrays=2', function benchmark( b ) {
+	var strides;
+	var values;
+	var buffer;
+	var offset;
+	var dtype;
+	var shape;
+	var order;
+	var out;
+	var y;
+	var i;
+
+	dtype = 'float64';
+	buffer = new Float64Array( 4 );
+	shape = [ 2, 2 ];
+	strides = [ 2, 1 ];
+	offset = 0;
+	order = 'row-major';
+
+	values = [
+		ndarrayBase( dtype, buffer, shape, strides, offset, order ),
+		ndarrayBase( dtype, buffer, shape, strides, offset, order ),
+		ndarrayBase( dtype, buffer, shape, strides, offset, order ),
+		ndarrayBase( dtype, buffer, shape, strides, offset, order ),
+		ndarrayBase( dtype, buffer, shape, strides, offset, order )
+	];
+	y = zeros( dtype, [ 2, 2, 2 ], order );
+
+	b.tic();
+	for ( i = 0; i < b.iterations; i++ ) {
+		out = broadcastArrays( [ values[ i%values.length ], y ] );
+		if ( typeof out !== 'object' ) {
+			b.fail( 'should return an object' );
+		}
+	}
+	b.toc();
+	if ( !isndarrayLike( out[ 0 ] ) || !isndarrayLike( out[ 1 ] ) ) {
+		b.fail( 'should return an array of ndarrays' );
+	}
+	b.pass( 'benchmark finished' );
+	b.end();
+});
+
+bench( pkg+'::ndarray,2d:num_arrays=2', function benchmark( b ) {
+	var strides;
+	var values;
+	var buffer;
+	var offset;
+	var dtype;
+	var shape;
+	var order;
+	var out;
+	var y;
+	var i;
+
+	dtype = 'float64';
+	buffer = new Float64Array( 4 );
+	shape = [ 2, 2 ];
+	strides = [ 2, 1 ];
+	offset = 0;
+	order = 'row-major';
+
+	values = [
+		ndarray( dtype, buffer, shape, strides, offset, order ),
+		ndarray( dtype, buffer, shape, strides, offset, order ),
+		ndarray( dtype, buffer, shape, strides, offset, order ),
+		ndarray( dtype, buffer, shape, strides, offset, order ),
+		ndarray( dtype, buffer, shape, strides, offset, order )
+	];
+	y = zeros( dtype, [ 2, 2, 2 ], order );
+
+	b.tic();
+	for ( i = 0; i < b.iterations; i++ ) {
+		out = broadcastArrays( [ values[ i%values.length ], y ] );
+		if ( typeof out !== 'object' ) {
+			b.fail( 'should return an object' );
+		}
+	}
+	b.toc();
+	if ( !isndarrayLike( out[ 0 ] ) || !isndarrayLike( out[ 1 ] ) ) {
+		b.fail( 'should return an array of ndarrays' );
+	}
+	b.pass( 'benchmark finished' );
+	b.end();
+});
+
+bench( pkg+'::ndarray_like,2d:num_arrays=2', function benchmark( b ) {
+	var strides;
+	var values;
+	var buffer;
+	var offset;
+	var dtype;
+	var shape;
+	var order;
+	var out;
+	var obj;
+	var y;
+	var i;
+
+	dtype = 'float64';
+	buffer = new Float64Array( 4 );
+	shape = [ 2, 2 ];
+	strides = [ 2, 1 ];
+	offset = 0;
+	order = 'row-major';
+
+	values = [];
+	for ( i = 0; i < 5; i++ ) {
+		obj = {
+			'dtype': dtype,
+			'data': buffer,
+			'shape': shape,
+			'strides': strides,
+			'offset': offset,
+			'order': order
+		};
+		values.push( obj );
+	}
+	y = zeros( dtype, [ 2, 2, 2 ], order );
+
+	b.tic();
+	for ( i = 0; i < b.iterations; i++ ) {
+		out = broadcastArrays( [ values[ i%values.length ], y ] );
+		if ( typeof out !== 'object' ) {
+			b.fail( 'should return an object' );
+		}
+	}
+	b.toc();
+	if ( !isndarrayLike( out[ 0 ] ) || !isndarrayLike( out[ 1 ] ) ) {
+		b.fail( 'should return an array of ndarrays' );
+	}
+	b.pass( 'benchmark finished' );
+	b.end();
+});