npm package: @stdlib/math-base-special-exp
Description: Natural exponential function.
Author: The Stdlib Authors
Latest version: 0.2.5

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<details>
  <summary>
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</details>

# exp

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

> Natural [exponential function][exponential-function].

<section class="intro">

The natural [exponential function][exponential-function] is defined as

<!-- <equation class="equation" label="eq:natural_exponential_function" align="center" raw="y = e^x" alt="Natural exponential function definition"> -->

<div class="equation" align="center" data-raw-text="y = e^x" data-equation="eq:natural_exponential_function">
    <img src="https://cdn.jsdelivr.net/gh/stdlib-js/stdlib@117273e7c4f27b0835723c2940d9675af0e14cb7/lib/node_modules/@stdlib/math/base/special/exp/docs/img/equation_natural_exponential_function.svg" alt="Natural exponential function definition">
    <br>
</div>

<!-- </equation> -->

where `e` is [Euler's][@stdlib/constants/float64/e] number.

</section>

<!-- /.intro -->

<section class="installation">

## Installation

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

</section>

<section class="usage">

## Usage

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

#### exp( x )

Evaluates the natural [exponential function][exponential-function].

```javascript
var v = exp( 4.0 );
// returns ~54.5982

v = exp( -9.0 );
// returns ~1.234e-4

v = exp( 0.0 );
// returns 1.0

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

</section>

<!-- /.usage -->

<section class="examples">

## Examples

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

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

var opts = {
    'dtype': 'float64'
};
var x = uniform( 100, -50.0, 50.0, opts );

logEachMap( 'e^%0.4f = %0.4f', x, exp );
```

</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/exp.h"
```

#### stdlib_base_exp( x )

Evaluates the natural [exponential function][exponential-function].

```c
double out = stdlib_base_exp( 4.0 );
// returns ~54.5982

out = stdlib_base_exp( -9.0 );
// returns ~1.234e-4
```

The function accepts the following arguments:

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

```c
double stdlib_base_exp( 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/exp.h"
#include <stdlib.h>
#include <stdio.h>

int main( void ) {
    double x;
    double v;
    int i;

    for ( i = 0; i < 100; i++ ) {
        x = ( (double)rand() / (double)RAND_MAX ) * 100.0;
        v = stdlib_base_exp( x );
        printf( "e^%lf = %lf\n", x, v );
    }
}
```

</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/exp10`][@stdlib/math/base/special/exp10]</span><span class="delimiter">: </span><span class="description">base 10 exponential function.</span>
-   <span class="package-name">[`@stdlib/math-base/special/exp2`][@stdlib/math/base/special/exp2]</span><span class="delimiter">: </span><span class="description">base 2 exponential function.</span>
-   <span class="package-name">[`@stdlib/math-base/special/expm1`][@stdlib/math/base/special/expm1]</span><span class="delimiter">: </span><span class="description">compute exp(x) - 1.</span>
-   <span class="package-name">[`@stdlib/math-base/special/ln`][@stdlib/math/base/special/ln]</span><span class="delimiter">: </span><span class="description">evaluate the natural logarithm of a double-precision floating-point number.</span>

</section>

<!-- /.related -->

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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

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

---

## Copyright

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

</section>

<!-- /.stdlib -->

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[npm-url]: https://npmjs.org/package/@stdlib/math-base-special-exp

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[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/math-base-special-exp/main.svg
[coverage-url]: https://codecov.io/github/stdlib-js/math-base-special-exp?branch=main

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

[stdlib-authors]: https://github.com/stdlib-js/stdlib/graphs/contributors

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

[deno-url]: https://github.com/stdlib-js/math-base-special-exp/tree/deno
[deno-readme]: https://github.com/stdlib-js/math-base-special-exp/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/math-base-special-exp/tree/umd
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[esm-url]: https://github.com/stdlib-js/math-base-special-exp/tree/esm
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[branches-url]: https://github.com/stdlib-js/math-base-special-exp/blob/main/branches.md

[exponential-function]: https://en.wikipedia.org/wiki/Exponential_function

[@stdlib/constants/float64/e]: https://www.npmjs.com/package/@stdlib/constants-float64-e

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

[@stdlib/math/base/special/exp10]: https://www.npmjs.com/package/@stdlib/math-base-special-exp10

[@stdlib/math/base/special/exp2]: https://www.npmjs.com/package/@stdlib/math-base-special-exp2

[@stdlib/math/base/special/expm1]: https://www.npmjs.com/package/@stdlib/math-base-special-expm1

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

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

</section>

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