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# toSorted

> Return a new [ndarray][@stdlib/ndarray/ctor] containing the elements of an input [ndarray][@stdlib/ndarray/ctor] sorted along one or more [ndarray][@stdlib/ndarray/ctor] dimensions.

<section class="usage">

## Usage

```javascript
var toSorted = require( '@stdlib/blas/ext/to-sorted' );
```

#### toSorted( x\[, sortOrder]\[, options] )

Returns a new [ndarray][@stdlib/ndarray/ctor] containing the elements of an input [ndarray][@stdlib/ndarray/ctor] sorted along one or more [ndarray][@stdlib/ndarray/ctor] dimensions.

```javascript
var array = require( '@stdlib/ndarray/array' );

var x = array( [ -1.0, 2.0, -3.0 ] );

var y = toSorted( x );
// returns <ndarray>[ -3.0, -1.0, 2.0 ]
```

The function has the following parameters:

-   **x**: input [ndarray][@stdlib/ndarray/ctor]. Must have a real-valued or "generic" [data type][@stdlib/ndarray/dtypes].
-   **sortOrder**: sort order (_optional_). May be either a scalar value, string, or an [ndarray][@stdlib/ndarray/ctor] having a real-valued or "generic" [data type][@stdlib/ndarray/dtypes]. If provided an [ndarray][@stdlib/ndarray/ctor], the value must have a shape which is [broadcast-compatible][@stdlib/ndarray/base/broadcast-shapes] with the complement of the shape defined by `options.dims`. For example, given the input shape `[2, 3, 4]` and `options.dims=[0]`, an [ndarray][@stdlib/ndarray/ctor] sort order must have a shape which is [broadcast-compatible][@stdlib/ndarray/base/broadcast-shapes] with the shape `[3, 4]`. Similarly, when performing the operation over all elements in a provided input [ndarray][@stdlib/ndarray/ctor], an [ndarray][@stdlib/ndarray/ctor] sort order must be a zero-dimensional [ndarray][@stdlib/ndarray/ctor]. By default, the sort order is `1` (i.e., increasing order).
-   **options**: function options (_optional_).

The function accepts the following options:

-   **dims**: list of dimensions over which to perform operation. If not provided, the function performs the operation over all elements in a provided input [ndarray][@stdlib/ndarray/ctor].
-   **dtype**: output [ndarray][@stdlib/ndarray/ctor] [data type][@stdlib/ndarray/dtypes].

By default, the function sorts elements in increasing order. To sort in a different order, provide a `sortOrder` argument.

```javascript
var array = require( '@stdlib/ndarray/array' );

var x = array( [ -1.0, 2.0, -3.0 ] );

var y = toSorted( x, -1.0 );
// returns <ndarray>[ 2.0, -1.0, -3.0 ]
```

In addition to numeric values, one can specify the sort order via one of the following string literals: `'ascending'`, `'asc'`, `'descending'`, or `'desc'`. The first two literals indicate to sort in ascending (i.e., increasing) order. The last two literals indicate to sort in descending (i.e., decreasing) order.

```javascript
var array = require( '@stdlib/ndarray/array' );

var x = array( [ -1.0, 2.0, -3.0 ] );

// Sort in ascending order:
var y = toSorted( x, 'asc' );
// returns <ndarray>[ -3.0, -1.0, 2.0 ]

// Sort in descending order:
y = toSorted( x, 'descending' );
// returns <ndarray>[ 2.0, -1.0, -3.0 ]
```

By default, the function performs the operation over all elements in a provided input [ndarray][@stdlib/ndarray/ctor]. To perform the operation over specific dimensions, provide a `dims` option.

```javascript
var array = require( '@stdlib/ndarray/array' );

var x = array( [ -1.0, 2.0, -3.0, 4.0 ], {
    'shape': [ 2, 2 ],
    'order': 'row-major'
});

var y = toSorted( x, {
    'dims': [ 0 ]
});
// returns <ndarray>[ [ -3.0, 2.0 ], [ -1.0, 4.0 ] ]
```

To specify the output [ndarray][@stdlib/ndarray/ctor] [data type][@stdlib/ndarray/dtypes], provide a `dtype` option.

```javascript
var array = require( '@stdlib/ndarray/array' );

var x = array( [ -1.0, 2.0, -3.0 ] );

var y = toSorted( x, {
    'dtype': 'float32'
});
// returns <ndarray>[ -3.0, -1.0, 2.0 ]
```

#### toSorted.assign( x\[, sortOrder], out\[, options] )

Sorts the elements of an input [ndarray][@stdlib/ndarray/ctor] along one or more [ndarray][@stdlib/ndarray/ctor] dimensions and assigns the results to an output [ndarray][@stdlib/ndarray/ctor].

```javascript
var zeros = require( '@stdlib/ndarray/zeros' );
var array = require( '@stdlib/ndarray/array' );

var x = array( [ -1.0, 2.0, -3.0 ] );
var y = zeros( [ 3 ] );

var out = toSorted.assign( x, y );
// returns <ndarray>[ -3.0, -1.0, 2.0 ]

var bool = ( y === out );
// returns true
```

The function has the following parameters:

-   **x**: input [ndarray][@stdlib/ndarray/ctor]. Must have a real-valued or "generic" [data type][@stdlib/ndarray/dtypes].
-   **sortOrder**: sort order (_optional_). May be either a scalar value, string, or an [ndarray][@stdlib/ndarray/ctor] having a real-valued or "generic" [data type][@stdlib/ndarray/dtypes]. If provided an [ndarray][@stdlib/ndarray/ctor], the value must have a shape which is [broadcast-compatible][@stdlib/ndarray/base/broadcast-shapes] with the complement of the shape defined by `options.dims`. For example, given the input shape `[2, 3, 4]` and `options.dims=[0]`, an [ndarray][@stdlib/ndarray/ctor] sort order must have a shape which is [broadcast-compatible][@stdlib/ndarray/base/broadcast-shapes] with the shape `[3, 4]`. Similarly, when performing the operation over all elements in a provided input [ndarray][@stdlib/ndarray/ctor], an [ndarray][@stdlib/ndarray/ctor] sort order must be a zero-dimensional [ndarray][@stdlib/ndarray/ctor]. By default, the sort order is `1` (i.e., increasing order).
-   **out**: output [ndarray][@stdlib/ndarray/ctor]. Must have a real-valued or "generic" [data type][@stdlib/ndarray/dtypes].
-   **options**: function options (_optional_).

The function accepts the following options:

-   **dims**: list of dimensions over which to perform operation. If not provided, the function performs the operation over all elements in a provided input [ndarray][@stdlib/ndarray/ctor].

</section>

<!-- /.usage -->

<section class="notes">

## Notes

-   If `sortOrder < 0.0` or is either `'desc'` or `'descending'`, the input [ndarray][@stdlib/ndarray/ctor] is sorted in **decreasing** order. If `sortOrder > 0.0` or is either `'asc'` or `'ascending'`, the input [ndarray][@stdlib/ndarray/ctor] is sorted in **increasing** order. If `sortOrder == 0.0`, the input [ndarray][@stdlib/ndarray/ctor] is left unchanged.
-   The algorithm distinguishes between `-0` and `+0`. When sorted in increasing order, `-0` is sorted before `+0`. When sorted in decreasing order, `-0` is sorted after `+0`.
-   The algorithm sorts `NaN` values to the end. When sorted in increasing order, `NaN` values are sorted last. When sorted in decreasing order, `NaN` values are sorted first.
-   The function iterates over [ndarray][@stdlib/ndarray/ctor] elements according to the memory layout of the input [ndarray][@stdlib/ndarray/ctor]. Accordingly, performance degradation is possible when operating over multiple dimensions of a large non-contiguous multi-dimensional input [ndarray][@stdlib/ndarray/ctor]. In such scenarios, one may want to copy an input [ndarray][@stdlib/ndarray/ctor] to contiguous memory before sorting.

</section>

<!-- /.notes -->

<section class="examples">

## Examples

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

```javascript
var discreteUniform = require( '@stdlib/random/discrete-uniform' );
var ndarray2array = require( '@stdlib/ndarray/to-array' );
var toSorted = require( '@stdlib/blas/ext/to-sorted' );

// Generate an ndarray of random numbers:
var x = discreteUniform( [ 5, 5 ], -20, 20, {
    'dtype': 'generic'
});
console.log( ndarray2array( x ) );

// Perform operation:
var out = toSorted( x, {
    'dims': [ 0 ]
});

// Print the results:
console.log( ndarray2array( out ) );
```

</section>

<!-- /.examples -->

<!-- Section for related `stdlib` packages. Do not manually edit this section, as it is automatically populated. -->

<section class="related">

</section>

<!-- /.related -->

<!-- Section for all links. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->

<section class="links">

[@stdlib/ndarray/ctor]: https://www.npmjs.com/package/@stdlib/ndarray-ctor

[@stdlib/ndarray/dtypes]: https://www.npmjs.com/package/@stdlib/ndarray-dtypes

[@stdlib/ndarray/base/broadcast-shapes]: https://www.npmjs.com/package/@stdlib/ndarray-base-broadcast-shapes

</section>

<!-- /.links -->
