npm package: @stdlib/math-base-special-fast-abs
Description: Compute an absolute value.
Author: The Stdlib Authors
Latest version: 0.3.1

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# Absolute Value

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

> 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.jsdelivr.net/gh/stdlib-js/stdlib@c1bdd27898df04d752ddb2dca37ca049e4c94d9b/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="installation">

## Installation

```bash
npm install @stdlib/math-base-special-fast-abs
```

</section>

<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 discreteUniform = require( '@stdlib/random-array-discrete-uniform' );
var logEachMap = require( '@stdlib/console-log-each-map' );
var abs = require( '@stdlib/math-base-special-fast-abs' );

var opts = {
    'dtype': 'float64'
};
var x = discreteUniform( 100, -50, 50, opts );

logEachMap( 'abs(%d) = %d', x, abs );
```

</section>

<!-- /.examples -->

<!-- C interface documentation. -->

* * *

<section class="c">

## C APIs

<!-- Section to include introductory text. Make sure to keep an empty line after the intro `section` element and another before the `/section` close. -->

<section class="intro">

</section>

<!-- /.intro -->

<!-- C usage documentation. -->

<section class="usage">

### Usage

```c
#include "stdlib/math/base/special/fast/abs.h"
```

#### stdlib_base_fast_abs( x )

Computes the absolute value of a double-precision floating-point number.

```c
double y = stdlib_base_fast_abs( -5.0 );
// returns 5.0
```

The function accepts the following arguments:

-   **x**: `[in] double` input value.

```c
double stdlib_base_fast_abs( const double x );
```

</section>

<!-- /.usage -->

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

<section class="notes">

</section>

<!-- /.notes -->

<!-- C API usage examples. -->

<section class="examples">

### Examples

```c
#include "stdlib/math/base/special/fast/abs.h"
#include <stdio.h>

int main( void ) {
    const double x[] = { 3.14, -3.14, 0.0, 0.0/0.0 };

    double y;
    int i;
    for ( i = 0; i < 4; i++ ) {
        y = stdlib_base_fast_abs( x[ i ] );
        printf( "|%lf| = %lf\n", x[ i ], y );
    }
}
```

</section>

<!-- /.examples -->

</section>

<!-- /.c -->

<!-- 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/math-base/special/abs`][@stdlib/math/base/special/abs]</span><span class="delimiter">: </span><span class="description">compute the absolute value of a double-precision floating-point number.</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="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

[![Chat][chat-image]][chat-url]

---

## License

See [LICENSE][stdlib-license].


## Copyright

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

</section>

<!-- /.stdlib -->

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[stdlib]: https://github.com/stdlib-js/stdlib

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[umd]: https://github.com/umdjs/umd
[es-module]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Modules

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[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/math-base-special-fast-abs/main/LICENSE

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

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

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[@stdlib/math/base/special/abs]: https://www.npmjs.com/package/@stdlib/math-base-special-abs

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</section>

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