@stdlib/ndarray-base-strides NPM

strides

Return the strides of a provided ndarray.

Installation

npm install @stdlib/ndarray-base-strides

Usage

var strides = require( '@stdlib/ndarray-base-strides' );

strides( x, copy )

Returns the strides of a provided ndarray.

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

var x = zeros( [ 3, 2, 3 ] );
// returns <ndarray>

var st = strides( x, false );
// returns [ 6, 3, 1 ]

When copy is false, changes to the returned strides array may mutate the input ndarray strides. If there is a chance that the returned strides will be mutated (either directly or by downstream consumers), set copy to true to prevent unintended side effects.

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

var x = zeros( [ 3, 2, 3 ] );
// returns <ndarray>

var st = strides( x, true );
// returns [ 6, 3, 1 ]

var bool = ( x.strides === st );
// returns false

Examples

var zeros = require( '@stdlib/ndarray-zeros' );
var slice = require( '@stdlib/ndarray-slice' );
var E = require( '@stdlib/slice-multi' );
var S = require( '@stdlib/slice-ctor' );
var strides = require( '@stdlib/ndarray-base-strides' );

// Create an array:
var x = zeros( [ 10, 10, 10, 10 ] );
// returns <ndarray>

// Define some slices:
var slices = [
    // :,:,:,:
    E( null, null, null, null ),

    // 5:10,4,2:4,::-1
    E( S( 5, 10 ), 4, S( 2, 4 ), S( null, null, -1 ) ),

    // :,:,2,:
    E( null, null, 2, null ),

    // 1,2,3,:
    E( 1, 2, 3, null ),

    // 1,3,::2,4::2
    E( 1, 3, S( null, null, 2 ), S( 4, null, 2 ) )
];

// Determine the strides of each slice...
var s;
var i;
for ( i = 0; i < slices.length; i++ ) {
    s = slice( x, slices[ i ] );
    console.log( '(%s) => (%s)', x.strides.join( ',' ), strides( s, false ).join( ',' ) );
}

Notice

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.

Community

License

See LICENSE.

@stdlib/ndarray-base-strides v0.2.1