time-to-botec/squiggle/node_modules/@stdlib/math/base/special/identityf/README.md

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# Identity Function

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

<section class="intro">

The [identity-function][identity-function] is defined as

<!-- <equation class="equation" label="eq:identity_function" align="center" raw="f(x) = x" alt="Identity function"> -->

<div class="equation" align="center" data-raw-text="f(x) = x" data-equation="eq:identity_function">
    <img src="https://cdn.jsdelivr.net/gh/stdlib-js/stdlib@ad4524117c3cf89854aeb12d7210102220874d31/lib/node_modules/@stdlib/math/base/special/identityf/docs/img/equation_identity_function.svg" alt="Identity function">
    <br>
</div>

<!-- </equation> -->

for all `x`.

</section>

<!-- /.intro -->

<section class="usage">

## Usage

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

#### identityf( x )

Evaluates the [identity function][identity-function] for a single-precision floating-point number.

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

v = identityf( 2.0 );
// returns 2.0

v = identityf( 0.0 );
// returns 0.0

v = identityf( -0.0 );
// returns -0.0

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

</section>

<!-- /.usage -->

<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 identityf = require( '@stdlib/math/base/special/identityf' );

var rand;
var i;

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

</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/identityf.h"
```

#### stdlib_base_identityf( x )

Evaluates the identity function for a single-precision floating-point number.

```c
float y = stdlib_base_identityf( 2.0f );
// returns 2.0f
```

The function accepts the following arguments:

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

```c
float stdlib_base_identityf( const float 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/identityf.h"
#include <stdio.h>

int main() {
    float x[] = { 3.14f, -3.14f, 0.0f, 0.0f/0.0f };

    float y;
    int i;
    for ( i = 0; i < 4; i++ ) {
        y = stdlib_base_identityf( x[ i ] );
        printf( "f(%f) = %f\n", x[ i ], y );
    }
}
```

</section>

<!-- /.examples -->

</section>

<!-- /.c -->

<section class="links">

[identity-function]: https://en.wikipedia.org/wiki/Identity_function

</section>

<!-- /.links -->