@stdlib/ndarray-base-strides2order

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strides2order

Determine the order of a multidimensional array based on a provided stride array.

Installation

npm install @stdlib/ndarray-base-strides2order

Usage

var strides2order = require( '@stdlib/ndarray-base-strides2order' );

strides2order( strides )

Determines the order of a multidimensional array based on a provided stride array.

var order = strides2order( [ 2, 1 ] );
// returns 1

order = strides2order( [ 1, 2 ] );
// returns 2

order = strides2order( [ 3 ] );
// returns 3

order = strides2order( [ 1, 3, 2 ] );
// returns 0

order = strides2order( [] );
// returns 0

The function returns one of the following values:

• 1: based on the stride array, the array is in row-major order.
• 2: based on the stride array, the array is in column-major order.
• 3: based on the stride array, the array is in both row-major and column-major order.
• 0: based on the stride array, the array is in neither row-major nor column-major order.

Examples

var discreteUniform = require( '@stdlib/random-base-discrete-uniform' );
var shape2strides = require( '@stdlib/ndarray-base-shape2strides' );
var randu = require( '@stdlib/random-base-randu' );
var strides2order = require( '@stdlib/ndarray-base-strides2order' );

var strides;
var order;
var shape;
var i;
var j;

shape = [ 0, 0, 0 ];

for ( i = 0; i < 20; i++ ) {
    // Generate a random array shape:
    shape[ 0 ] = discreteUniform( 1, 10 );
    shape[ 1 ] = discreteUniform( 1, 10 );
    shape[ 2 ] = discreteUniform( 1, 10 );

    // Compute the strides:
    if ( randu() < 0.5 ) {
        strides = shape2strides( shape, 'row-major' );
    } else {
        strides = shape2strides( shape, 'column-major' );
    }
    j = discreteUniform( 0, shape.length-1 );
    strides[ j ] *= ( randu() < 0.5 ) ? -1 : 1;

    // Determine the order:
    order = strides2order( strides );
    console.log( 'Strides: %s. Order: %s.', strides.join( ',' ), order );
}

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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

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License

See LICENSE.

Copyright

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