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Expand the shape of an array to a specified dimensionality by spreading its dimensions to specified dimension indices and inserting dimensions of size one for the remaining dimensions.
npm install @stdlib/ndarray-base-spread-dimensionsAlternatively,
- To load the package in a website via a
scripttag without installation and bundlers, use the ES Module available on theesmbranch (see README). - If you are using Deno, visit the
denobranch (see README for usage intructions). - For use in Observable, or in browser/node environments, use the Universal Module Definition (UMD) build available on the
umdbranch (see README).
The branches.md 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.
var spreadDimensions = require( '@stdlib/ndarray-base-spread-dimensions' );Expands the shape of an array to a specified dimensionality by spreading its dimensions to specified dimension indices and inserting dimensions of size one for the remaining dimensions.
var ndarray2array = require( '@stdlib/ndarray-to-array' );
var array = require( '@stdlib/ndarray-array' );
// Create a 2x2 ndarray:
var x = array( [ [ 1, 2 ], [ 3, 4 ] ] );
// returns <ndarray>
// Prepend a singleton dimension:
var y = spreadDimensions( 3, x, [ 1, 2 ] );
// returns <ndarray>
var sh = y.shape;
// returns [ 1, 2, 2 ]
var a = ndarray2array( y );
// returns [ [ [ 1, 2 ], [ 3, 4 ] ] ]
// Append a singleton dimension:
y = spreadDimensions( 3, x, [ 0, 1 ] );
// returns <ndarray>
sh = y.shape;
// returns [ 2, 2, 1 ]
a = ndarray2array( y );
// returns [ [ [ 1 ], [ 2 ] ], [ [ 3 ], [ 4 ] ] ]
// Insert a singleton dimension:
y = spreadDimensions( 3, x, [ 0, 2 ] );
// returns <ndarray>
sh = y.shape;
// returns [ 2, 1, 2 ]
a = ndarray2array( y );
// returns [ [ [ 1, 2 ] ], [ [ 3, 4 ] ] ]- Each provided dimension index must reside on the interval
[-ndims, ndims-1]. If provided a negative dimension index, the position at which to place a respective dimension is computed asndims + index. - Provided dimension indices must resolve to normalized dimension indices arranged in ascending order.
var array = require( '@stdlib/ndarray-array' );
var numel = require( '@stdlib/ndarray-base-numel' );
var ind2sub = require( '@stdlib/ndarray-ind2sub' );
var spreadDimensions = require( '@stdlib/ndarray-base-spread-dimensions' );
// Create a 2-dimensional array:
var x = array( [ [ 1, 2 ], [ 3, 4 ] ], {
'order': 'column-major'
});
// returns <ndarray>
// Spread dimensions:
var y = spreadDimensions( 5, x, [ 1, 3 ] );
// returns <ndarray>
// Retrieve the shape:
var sh = y.shape;
// returns [ 1, 2, 1, 2, 1 ]
// 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 ) );
}This package is part of 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, see the main project repository.
See LICENSE.
Copyright © 2016-2025. The Stdlib Authors.
