npm package: @stdlib/blas-ext-to-sortedhp
Description: Return a new ndarray containing the elements of an input ndarray sorted along one or more ndarray dimensions using heapsort.
Author: The Stdlib Authors
Latest version: 0.1.1

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# toSortedhp

[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url] <!-- [![dependencies][dependencies-image]][dependencies-url] -->

> 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 using heapsort.

<section class="installation">

## Installation

```bash
npm install @stdlib/blas-ext-to-sortedhp
```

</section>

<section class="usage">

## Usage

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

#### toSortedhp( 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 using heapsort.

```javascript
var ndarray2array = require( '@stdlib/ndarray-to-array' );
var array = require( '@stdlib/ndarray-array' );

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

var y = toSortedhp( x );
// returns <ndarray>

var arr = ndarray2array( y );
// returns [ -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 ndarray2array = require( '@stdlib/ndarray-to-array' );
var array = require( '@stdlib/ndarray-array' );

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

var y = toSortedhp( x, -1.0 );
// returns <ndarray>

var arr = ndarray2array( y );
// returns [ 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 ndarray2array = require( '@stdlib/ndarray-to-array' );
var array = require( '@stdlib/ndarray-array' );

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

// Sort in ascending order:
var y = toSortedhp( x, 'asc' );
// returns <ndarray>

var arr = ndarray2array( y );
// returns [ -3.0, -1.0, 2.0 ]

// Sort in descending order:
y = toSortedhp( x, 'descending' );
// returns <ndarray>

arr = ndarray2array( y );
// returns [ 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 ndarray2array = require( '@stdlib/ndarray-to-array' );
var array = require( '@stdlib/ndarray-array' );

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

var v = ndarray2array( x );
// returns [ [ -1.0, 2.0 ], [ -3.0, 4.0 ] ]

var y = toSortedhp( x, {
    'dims': [ 0 ]
});
// returns <ndarray>

v = ndarray2array( y );
// returns [ [ -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 ndarray2array = require( '@stdlib/ndarray-to-array' );
var array = require( '@stdlib/ndarray-array' );

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

var y = toSortedhp( x, {
    'dtype': 'float32'
});
// returns <ndarray>

var arr = ndarray2array( y );
// returns [ -3.0, -1.0, 2.0 ]
```

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

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

```javascript
var ndarray2array = require( '@stdlib/ndarray-to-array' );
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 = toSortedhp.assign( x, y );
// returns <ndarray>

var arr = ndarray2array( out );
// returns [ -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].
-   **out**: output [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].

</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 algorithm has space complexity `O(1)` and time complexity `O(N log2 N)`.
-   The algorithm is **unstable**, meaning that the algorithm may change the order of [ndarray][@stdlib/ndarray/ctor] elements which are equal or equivalent (e.g., `NaN` values).
-   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-array-discrete-uniform' );
var ndarray2array = require( '@stdlib/ndarray-to-array' );
var ndarray = require( '@stdlib/ndarray-ctor' );
var toSortedhp = require( '@stdlib/blas-ext-to-sortedhp' );

// Generate an array of random numbers:
var xbuf = discreteUniform( 25, -20, 20, {
    'dtype': 'generic'
});

// Wrap in an ndarray:
var x = new ndarray( 'generic', xbuf, [ 5, 5 ], [ 5, 1 ], 0, 'row-major' );
console.log( ndarray2array( x ) );

// Perform operation:
var out = toSortedhp( 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 -->

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<section class="main-repo" >

* * *

## 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].

</section>

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