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# Absolute Value

> Compute an [absolute value][absolute-value].

<section class="intro">

The [absolute value][absolute-value] is defined as

<!-- <equation class="equation" label="eq:absolute_value" align="center" raw="|x| = \begin{cases} x & \textrm{if}\ x \geq 0 \\ -x & \textrm{if}\ x < 0\end{cases}" alt="Absolute value"> -->

<div class="equation" align="center" data-raw-text="|x| = \begin{cases} x &amp; \textrm{if}\ x \geq 0 \\ -x &amp; \textrm{if}\ x &lt; 0\end{cases}" data-equation="eq:absolute_value">
    <img src="https://cdn.rawgit.com/stdlib-js/stdlib/7e0a95722efd9c771b129597380c63dc6715508b/lib/node_modules/@stdlib/math/base/special/fast/abs/docs/img/equation_absolute_value.svg" alt="Absolute value">
    <br>
</div>

<!-- </equation> -->

</section>

<!-- /.intro -->

<section class="usage">

## Usage

```javascript
var abs = require( '@stdlib/math/base/special/fast/abs' );
```

#### abs( x )

Computes an [absolute value][absolute-value].

```javascript
var v = abs( -1.0 );
// returns 1.0

v = abs( 2.0 );
// returns 2.0

v = abs( 0.0 );
// returns 0.0

v = abs( NaN );
// returns NaN
```

</section>

<!-- /.usage -->

<!-- Package usage notes. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->

<section class="notes">

## Notes

-   This implementation is **not** [IEEE 754][ieee754] compliant. If provided `-0`, the function returns `-0`.

    ```javascript
    var v = abs( -0.0 );
    // returns -0.0
    ```

</section>

<!-- /.notes -->

<section class="examples">

## Examples

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

```javascript
var randu = require( '@stdlib/random/base/randu' );
var round = require( '@stdlib/math/base/special/round' );
var abs = require( '@stdlib/math/base/special/fast/abs' );

var rand;
var i;

for ( i = 0; i < 100; i++ ) {
    rand = round( randu() * 100.0 ) - 50.0;
    console.log( 'abs(%d) = %d', rand, abs( rand ) );
}
```

</section>

<!-- /.examples -->

<section class="links">

[absolute-value]: https://en.wikipedia.org/wiki/Absolute_value

[ieee754]: https://en.wikipedia.org/wiki/IEEE_754-1985

</section>

<!-- /.links -->
