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# cphasef

> Compute the [argument][complex-number-argument] of a single-precision complex floating-point number in radians.

<section class="intro">

The [argument][complex-number-argument] of a complex number, also known as the **phase**, is the angle of the radius extending from the origin to the complex number plotted in the complex plane and the positive real axis.

</section>

<!-- /.intro -->

<section class="usage">

## Usage

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

#### cphasef( z )

Computes the [argument][complex-number-argument] of a single-precision complex floating-point number.

```javascript
var Complex64 = require( '@stdlib/complex/float32/ctor' );

var phi = cphasef( new Complex64( 5.0, 3.0 ) );
// returns ~0.5404
```

</section>

<!-- /.usage -->

<section class="examples">

## Examples

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

```javascript
var Complex64Array = require( '@stdlib/array/complex64' );
var uniform = require( '@stdlib/random/array/uniform' );
var logEachMap = require( '@stdlib/console/log-each-map' );
var cphasef = require( '@stdlib/math/base/special/cphasef' );

// Create an array of random numbers:
var arr = new Complex64Array( uniform( 200, -100.0, 100.0 ) );

// Compute the argument of each number in the array:
logEachMap( 'cphasef(%s) = %0.4f', arr, cphasef );
```

</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/cphasef.h"
```

#### stdlib_base_cphasef( z )

Computes the [argument][complex-number-argument] 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( 5.0f, 3.0f );
float out = stdlib_base_cphasef( z );
// returns ~0.5404f
```

The function accepts the following arguments:

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

```c
float stdlib_base_cphasef( 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>

<!-- /.notes -->

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

<section class="examples">

### Examples

```c
#include "stdlib/math/base/special/cphasef.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, 1.0f ),
        stdlib_complex64( -3.14f, -1.0f ),
        stdlib_complex64( 0.0f, 0.0f ),
        stdlib_complex64( 0.0f/0.0f, 0.0f/0.0f )
    };

    stdlib_complex64_t v;
    float re;
    float im;
    float y;
    int i;
    for ( i = 0; i < 4; i++ ) {
        v = x[ i ];
        y = stdlib_base_cphasef( v );
        stdlib_complex64_reim( v, &re, &im );
        printf( "cphasef(%f + %fi) = %f\n", re, im, y );
    }
}
```

</section>

<!-- /.examples -->

</section>

<!-- /.c -->

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

<section class="related">

</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">

[complex-number-argument]: https://en.wikipedia.org/wiki/Argument_%28complex_analysis%29

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

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

</section>

<!-- /.links -->
