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# ssortins

> Sort a single-precision floating-point strided array using insertion sort.

<section class="usage">

## Usage

```javascript
var ssortins = require( '@stdlib/blas/ext/base/ssortins' );
```

#### ssortins( N, order, x, stride )

Sorts a single-precision floating-point strided array `x` using insertion sort.

```javascript
var Float32Array = require( '@stdlib/array/float32' );

var x = new Float32Array( [ 1.0, -2.0, 3.0, -4.0 ] );

ssortins( x.length, 1.0, x, 1 );
// x => <Float32Array>[ -4.0, -2.0, 1.0, 3.0 ]
```

The function has the following parameters:

-   **N**: number of indexed elements.
-   **order**: sort order. If `order < 0.0`, the input strided array is sorted in **decreasing** order. If `order > 0.0`, the input strided array is sorted in **increasing** order. If `order == 0.0`, the input strided array is left unchanged.
-   **x**: input [`Float32Array`][@stdlib/array/float32].
-   **stride**: index increment.

The `N` and stride parameters determine which elements in the strided array are accessed at runtime. For example, to sort every other element

```javascript
var Float32Array = require( '@stdlib/array/float32' );

var x = new Float32Array( [ 1.0, -2.0, 3.0, -4.0 ] );

ssortins( 2, -1.0, x, 2 );
// x => <Float32Array>[ 3.0, -2.0, 1.0, -4.0 ]
```

Note that indexing is relative to the first index. To introduce an offset, use [`typed array`][mdn-typed-array] views.

```javascript
var Float32Array = require( '@stdlib/array/float32' );

// Initial array...
var x0 = new Float32Array( [ 1.0, 2.0, 3.0, 4.0 ] );

// Create an offset view...
var x1 = new Float32Array( x0.buffer, x0.BYTES_PER_ELEMENT*1 ); // start at 2nd element

// Sort every other element...
ssortins( 2, -1.0, x1, 2 );
// x0 => <Float32Array>[ 1.0, 4.0, 3.0, 2.0 ]
```

#### ssortins.ndarray( N, order, x, stride, offset )

Sorts a single-precision floating-point strided array `x` using insertion sort and alternative indexing semantics.

```javascript
var Float32Array = require( '@stdlib/array/float32' );

var x = new Float32Array( [ 1.0, -2.0, 3.0, -4.0 ] );

ssortins.ndarray( x.length, 1.0, x, 1, 0 );
// x => <Float32Array>[ -4.0, -2.0, 1.0, 3.0 ]
```

The function has the following additional parameters:

-   **offset**: starting index.

While [`typed array`][mdn-typed-array] views mandate a view offset based on the underlying `buffer`, the offset parameter supports indexing semantics based on a starting index. For example, to access only the last three elements of `x`

```javascript
var Float32Array = require( '@stdlib/array/float32' );

var x = new Float32Array( [ 1.0, -2.0, 3.0, -4.0, 5.0, -6.0 ] );

ssortins.ndarray( 3, 1.0, x, 1, x.length-3 );
// x => <Float32Array>[ 1.0, -2.0, 3.0, -6.0, -4.0, 5.0 ]
```

</section>

<!-- /.usage -->

<section class="notes">

## Notes

-   If `N <= 0` or `order == 0.0`, both functions return `x` 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 worst case time complexity `O(N^2)`.
-   The algorithm is efficient for **small** strided arrays (typically `N <= 20`) and is particularly efficient for sorting strided arrays which are already substantially sorted.
-   The algorithm is **stable**, meaning that the algorithm does **not** change the order of strided array elements which are equal or equivalent (e.g., `NaN` values).
-   The input strided array is sorted **in-place** (i.e., the input strided array is **mutated**).

</section>

<!-- /.notes -->

<section class="examples">

## Examples

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

```javascript
var round = require( '@stdlib/math/base/special/round' );
var randu = require( '@stdlib/random/base/randu' );
var Float32Array = require( '@stdlib/array/float32' );
var ssortins = require( '@stdlib/blas/ext/base/ssortins' );

var rand;
var sign;
var i;

var x = new Float32Array( 10 );
for ( i = 0; i < x.length; i++ ) {
    rand = round( randu()*100.0 );
    sign = randu();
    if ( sign < 0.5 ) {
        sign = -1.0;
    } else {
        sign = 1.0;
    }
    x[ i ] = sign * rand;
}
console.log( x );

ssortins( x.length, -1.0, x, -1 );
console.log( x );
```

</section>

<!-- /.examples -->

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

<section class="related">

* * *

## See Also

-   <span class="package-name">[`@stdlib/blas/ext/base/dsortins`][@stdlib/blas/ext/base/dsortins]</span><span class="delimiter">: </span><span class="description">sort a double-precision floating-point strided array using insertion sort.</span>
-   <span class="package-name">[`@stdlib/blas/ext/base/gsortins`][@stdlib/blas/ext/base/gsortins]</span><span class="delimiter">: </span><span class="description">sort a strided array using insertion sort.</span>
-   <span class="package-name">[`@stdlib/blas/ext/base/ssort2ins`][@stdlib/blas/ext/base/ssort2ins]</span><span class="delimiter">: </span><span class="description">simultaneously sort two single-precision floating-point strided arrays based on the sort order of the first array using insertion sort.</span>

</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/array/float32]: https://www.npmjs.com/package/@stdlib/array-float32

[mdn-typed-array]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray

<!-- <related-links> -->

[@stdlib/blas/ext/base/dsortins]: https://github.com/stdlib-js/blas/tree/main/ext/base/dsortins

[@stdlib/blas/ext/base/gsortins]: https://github.com/stdlib-js/blas/tree/main/ext/base/gsortins

[@stdlib/blas/ext/base/ssort2ins]: https://github.com/stdlib-js/blas/tree/main/ext/base/ssort2ins

<!-- </related-links> -->

</section>

<!-- /.links -->
