time-to-botec/squiggle/node_modules/@stdlib/ndarray/base/assert/is-column-major-contiguous

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.

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 );
}