npm package: @stdlib/math-base-special-kernel-tanf
Description: Compute the tangent of a number on [-π/4, π/4] in single-precision floating-point format.
Author: The Stdlib Authors
Latest version: 0.1.1

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# kernelTanf

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

> Compute the [tangent][tangent] of a number on `[-π/4, π/4]` in single-precision floating-point format.

<section class="installation">

## Installation

```bash
npm install @stdlib/math-base-special-kernel-tanf
```

</section>

<section class="usage">

## Usage

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

#### kernelTanf( x, iy )

Computes the [tangent][tangent] of a number on `[-π/4, π/4]` in single-precision floating-point format.

```javascript
var out = kernelTanf( 3.141592653589793/4.0, 1 );
// returns ~1.0

out = kernelTanf( 3.141592653589793/6.0, 1 );
// returns ~0.577

out = kernelTanf( 0.664, 1 );
// returns ~0.783
```

If `k = 1`, the function returns `tan(x)`. To return the negative inverse `-1/tan(x)`, set `k = -1`.

```javascript
var out = kernelTanf( 3.141592653589793/4.0, -1 );
// returns ~-1.0
```

If provided `NaN` for `x`, the function returns `NaN`.

```javascript
var out = kernelTanf( NaN, 1 );
// returns NaN

out = kernelTanf( NaN, -1 );
// returns NaN
```

</section>

<!-- /.usage -->

<section class="examples">

## Examples

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

```javascript
var linspace = require( '@stdlib/array-base-linspace' );
var PI = require( '@stdlib/constants-float32-pi' );
var logEachMap = require( '@stdlib/console-log-each-map' );
var kernelTanf = require( '@stdlib/math-base-special-kernel-tanf' );

var x = linspace( -PI/4.0, PI/4.0, 100 );

logEachMap( 'kernelTanf(%0.4f, %d) = %0.4f', x, 1, kernelTanf );
```

</section>

<!-- /.examples -->

<!-- C interface documentation. -->

* * *

<section class="c">

## C APIs

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<section class="intro">

</section>

<!-- /.intro -->

<!-- C usage documentation. -->

<section class="usage">

### Usage

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

#### stdlib_base_kernel_tanf( x, iy )

Computes the [tangent][tangent] of a number on `[-π/4, π/4]` in single-precision floating-point format.

```c
float out = stdlib_base_kernel_tanf( 3.141592653589793/4.0, 1 );
// returns ~1.0f

out = stdlib_base_kernel_tanf( 3.141592653589793/6.0, 1 );
// returns ~0.577f
```

The function accepts the following arguments:

-   **x**: `[in] double` input value (in radians, assumed to be bounded by `~pi/4` in magnitude).
-   **iy**: `[in] int32_t` indicates whether `tan(x)` (if `iy = 1`) or `-1/tan(x)` (if `iy = -1`) is returned.

```c
float stdlib_base_kernel_tanf( const double x, const int32_t iy );
```

</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/kernel_tanf.h"
#include <stdio.h>

int main( void ) {
    const double x[] = { -0.7853981633974483, -0.6108652381980153, -0.4363323129985824, -0.26179938779914946, -0.08726646259971649, 0.08726646259971649, 0.26179938779914935, 0.43633231299858233, 0.6108652381980153, 0.7853981633974483 };

    float out;
    int i;
    for ( i = 0; i < 10; i++ ) {
        out = stdlib_base_kernel_tanf( x[ i ], 1 );
        printf( "kernelTanf(%lf, %d) = %f\n", x[ i ], 1, out );
    }
}
```

</section>

<!-- /.examples -->

</section>

<!-- /.c -->

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<section class="related">

</section>

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<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

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---

## Copyright

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

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[umd]: https://github.com/umdjs/umd
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[tangent]: https://en.wikipedia.org/wiki/Tangent

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</section>

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