@stdlib/ndarray-base-assert-is-column-major-contig

isColumnMajorContiguous

Determine if an array is column-major contiguous.

An array is contiguous if the memory address of each array element is adjacent to the memory address of the next array element.

Installation

npm install @stdlib/ndarray-base-assert-is-column-major-contiguous

Usage

var isColumnMajorContiguous = require( '@stdlib/ndarray-base-assert-is-column-major-contiguous' );

isColumnMajorContiguous( shape, strides, offset )

Returns a boolean indicating if an array is column-major contiguous.

var shape = [ 2, 2 ];
var strides = [ 1, 2 ];
var offset = 25;

var bool = isColumnMajorContiguous( shape, strides, offset );
// returns true

shape = [ 10 ];
strides = [ 3 ]; // every third memory element
offset = 0;

bool = isColumnMajorContiguous( shape, strides, offset );
// returns false

Examples

var discreteUniform = require( '@stdlib/random-base-discrete-uniform' );
var shape2strides = require( '@stdlib/ndarray-base-shape2strides' );
var strides2offset = require( '@stdlib/ndarray-base-strides2offset' );
var randu = require( '@stdlib/random-base-randu' );
var isColumnMajorContiguous = require( '@stdlib/ndarray-base-assert-is-column-major-contiguous' );

var strides;
var offset;
var shape;
var bool;
var i;
var j;

shape = [ 0, 0, 0 ];

for ( i = 0; i < 100; i++ ) {
    // Generate a random array shape:
    shape[ 0 ] = discreteUniform( 1, 10 );
    shape[ 1 ] = discreteUniform( 1, 10 );
    shape[ 2 ] = discreteUniform( 1, 10 );

    // Generate 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;

    strides[ 0 ] *= discreteUniform( 1, 2 ); // if scaled by 1, then single segment

    // Compute the index offset:
    offset = strides2offset( shape, strides ) + 25; // include a view offset

    // Determine if the array is column-major contiguous:
    bool = isColumnMajorContiguous( shape, strides, offset );
    console.log( 'Shape: %s. Strides: %s. Offset: %d. Contiguous: %s.', shape.join( 'x' ), strides.join( ',' ), offset, bool );
}

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.