Given a stride array, determine array iteration order.
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> Given a stride array, determine array iteration order.
``bash`
npm install @stdlib/ndarray-base-iteration-order
`javascript`
var iterationOrder = require( '@stdlib/ndarray-base-iteration-order' );
#### iterationOrder( strides )
Returns the array iteration order.
`javascript
var o = iterationOrder( [ 2, 1 ] );
// returns 1
o = iterationOrder( [ -2, 1 ] );
// returns 0
o = iterationOrder( [ -2, -1 ] );
// returns -1
`
The function returns one of the following values:
- 0: unordered (strides are of mixed sign).1
- : left-to-right iteration order (strides are all nonnegative).-1
- : right-to-left iteration order (strides are all negative).
`javascript
var discreteUniform = require( '@stdlib/random-base-discrete-uniform' );
var shape2strides = require( '@stdlib/ndarray-base-shape2strides' );
var randu = require( '@stdlib/random-base-randu' );
var iterationOrder = require( '@stdlib/ndarray-base-iteration-order' );
var strides;
var shape;
var out;
var i;
var j;
shape = [ 0, 0, 0 ];
shape[ 0 ] = discreteUniform( 1, 10 );
shape[ 1 ] = discreteUniform( 1, 10 );
shape[ 2 ] = discreteUniform( 1, 10 );
strides = shape2strides( shape, 'row-major' );
for ( i = 0; i < 100; i++ ) {
j = discreteUniform( 0, shape.length-1 );
strides[ j ] *= ( randu() < 0.5 ) ? -1 : 1;
out = iterationOrder( strides );
console.log( 'strides: %s => %d', strides.join( ',' ), out );
}
`
*
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