npm package: @stdlib/ndarray-base-iteration-order
Description: Given a stride array, determine array iteration order.
Author: The Stdlib Authors
Latest version: 0.2.3

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# Iteration Order

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> Given a stride array, determine array iteration order.

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<section class="installation">

## Installation

```bash
npm install @stdlib/ndarray-base-iteration-order
```

</section>

<section class="usage">

## Usage

```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).

</section>

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<section class="examples">

## Examples

<!-- eslint no-undef: "error" -->

```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 );
}
```

</section>

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* * *

## Notice

This package is part of [stdlib][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][stdlib], see the main project [repository][stdlib].

#### Community

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---

## License

See [LICENSE][stdlib-license].


## Copyright

Copyright &copy; 2016-2026. The Stdlib [Authors][stdlib-authors].

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