npm package: @stdlib/math-base-special-csignumf
Description: Evaluate the signum function of a single-precision complex floating-point number.
Author: The Stdlib Authors
Latest version: 0.1.1

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# csignumf

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> Evaluate the [signum][signum] function of a single-precision complex floating-point number.

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<section class="intro">

</section>

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<section class="installation">

## Installation

```bash
npm install @stdlib/math-base-special-csignumf
```

</section>

<section class="usage">

## Usage

```javascript
var csignumf = require( '@stdlib/math-base-special-csignumf' );
```

#### csignumf( z )

Evaluates the [signum][signum] function of a single-precision complex floating-point number.

```javascript
var Complex64 = require( '@stdlib/complex-float32-ctor' );
var v = csignumf( new Complex64( -4.2, 5.5 ) );
// returns <Complex64>[ ~-0.607, ~0.795 ]

v = csignumf( new Complex64( 0.0, 0.0 ) );
// returns <Complex64>[ 0.0, 0.0 ]

v = csignumf( new Complex64( NaN, NaN ) );
// returns <Complex64>[ NaN, NaN ]
```

</section>

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<section class="notes">

</section>

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<!-- Package usage examples. -->

<section class="examples">

## Examples

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

```javascript
var uniform = require( '@stdlib/random-base-uniform' ).factory;
var Complex64 = require( '@stdlib/complex-float32-ctor' );
var csignumf = require( '@stdlib/math-base-special-csignumf' );

var rand = uniform( -50.0, 50.0 );

var z;
var i;
for ( i = 0; i < 100; i++ ) {
    z = new Complex64( rand(), rand() );
    console.log( 'csignumf(%s) = %s', z, csignumf( z ) );
}
```

</section>

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<!-- C interface documentation. -->

* * *

<section class="c">

## C APIs

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</section>

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<section class="usage">

### Usage

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

#### stdlib_base_csignumf( z )

Evaluates the [signum][signum] function of a single-precision complex floating-point number.

```c
#include "stdlib/complex/float32/ctor.h"
#include "stdlib/complex/float32/real.h"
#include "stdlib/complex/float32/imag.h"

stdlib_complex64_t z = stdlib_complex64( -4.2f, 5.5f );

stdlib_complex64_t out = stdlib_base_csignumf( z );

float re = stdlib_complex64_real( out );
// returns ~-0.607f

float im = stdlib_complex64_imag( out );
// returns ~0.795f
```

The function accepts the following arguments:

-   **z**: `[in] stdlib_complex64_t` input value.

```c
stdlib_complex64_t stdlib_base_csignumf( const stdlib_complex64_t z );
```

</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>

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

<section class="examples">

### Examples

```c
#include "stdlib/math/base/special/csignumf.h"
#include "stdlib/complex/float32/ctor.h"
#include "stdlib/complex/float32/reim.h"
#include <stdio.h>

int main( void ) {
    const stdlib_complex64_t x[] = {
        stdlib_complex64( 3.14f, 1.5f ),
        stdlib_complex64( -3.14f, -1.5f ),
        stdlib_complex64( 0.0f, 0.0f ),
        stdlib_complex64( 0.0f/0.0f, 0.0f/0.0f )
    };

    stdlib_complex64_t v;
    stdlib_complex64_t y;
    float re1;
    float im1;
    float re2;
    float im2;
    int i;
    for ( i = 0; i < 4; i++ ) {
        v = x[ i ];
        y = stdlib_base_csignumf( v );
        stdlib_complex64_reim( v, &re1, &im1 );
        stdlib_complex64_reim( y, &re2, &im2 );
        printf( "csignumf(%f + %fi) = %f + %fi\n", re1, im1, re2, im2 );
    }
}
```

</section>

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</section>

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* * *

## 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].

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---

## License

See [LICENSE][stdlib-license].


## Copyright

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

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[signum]: https://en.wikipedia.org/wiki/Sign_function

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