Relative error exponential.
npm install @stdlib/math-base-special-expm1relWe believe in a future in which the web is a preferred environment for numerical computation. To help realize this future, we've built stdlib. stdlib is a standard library, with an emphasis on numerical and scientific computation, written in JavaScript (and C) for execution in browsers and in Node.js. The library is fully decomposable, being architected in such a way that you can swap out and mix and match APIs and functionality to cater to your exact preferences and use cases. When you use stdlib, you can be absolutely certain that you are using the most thorough, rigorous, well-written, studied, documented, tested, measured, and high-quality code out there. To join us in bringing numerical computing to the web, get started by checking us out on GitHub, and please consider financially supporting stdlib. We greatly appreciate your continued support!
About stdlib...
[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url]
> Compute the relative error exponential.
The relative error exponential is defined as
``bash`
npm install @stdlib/math-base-special-expm1rel
`javascript`
var expm1rel = require( '@stdlib/math-base-special-expm1rel' );
#### expm1rel( x )
Computes the relative error exponential.
`javascript
var v = expm1rel( 0.0 );
// returns 1.0
v = expm1rel( 1.0 );
// returns ~1.718
v = expm1rel( -1.0 );
// returns ~0.632
v = expm1rel( NaN );
// returns NaN
`
- When x is near zero, exp(x)-1 can suffer catastrophic cancellation (i.e., a significant loss in precision). expm1rel avoids such a loss in precision.
`javascript
var uniform = require( '@stdlib/random-array-uniform' );
var logEachMap = require( '@stdlib/console-log-each-map' );
var expm1rel = require( '@stdlib/math-base-special-expm1rel' );
var opts = {
'dtype': 'float64'
};
var x = uniform( 100, -50.0, 50.0, opts );
logEachMap( '(e^%0.3f - 1)/%0.3f = %0.3f', x, x, expm1rel );
`
*
`c`
#include "stdlib/math/base/special/expm1rel.h"
#### stdlib_base_expm1rel( x )
Computes the relative error exponential.
`c
double out = stdlib_base_expm1rel( 0.0 );
// returns 1.0
out = stdlib_base_expm1rel( 1.0 );
// returns ~1.718
`
The function accepts the following arguments:
- x: [in] double input value.
`c`
double stdlib_base_expm1rel( const double x );
`c
#include "stdlib/math/base/special/expm1rel.h"
#include
#include
int main( void ) {
double x;
double v;
int i;
for ( i = 0; i < 100; i++ ) {
x = ( ( (double)rand() / (double)RAND_MAX ) * 100.0 ) - 50.0;
v = stdlib_base_expm1rel( x );
printf( "(e^%lf - 1)/%lf = %lf\n", x, x, v );
}
}
`
*
- [@stdlib/math-base/special/exp][@stdlib/math/base/special/exp]: natural exponential function.
- [@stdlib/math-base/special/expm1][@stdlib/math/base/special/expm1]: compute exp(x) - 1.
*
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]
---
See [LICENSE][stdlib-license].
Copyright © 2016-2026. The Stdlib [Authors][stdlib-authors].
[npm-image]: http://img.shields.io/npm/v/@stdlib/math-base-special-expm1rel.svg
[npm-url]: https://npmjs.org/package/@stdlib/math-base-special-expm1rel
[test-image]: https://github.com/stdlib-js/math-base-special-expm1rel/actions/workflows/test.yml/badge.svg?branch=v0.2.4
[test-url]: https://github.com/stdlib-js/math-base-special-expm1rel/actions/workflows/test.yml?query=branch:v0.2.4
[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/math-base-special-expm1rel/main.svg
[coverage-url]: https://codecov.io/github/stdlib-js/math-base-special-expm1rel?branch=main
[chat-image]: https://img.shields.io/badge/zulip-join_chat-brightgreen.svg
[chat-url]: https://stdlib.zulipchat.com
[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-expm1rel/tree/deno
[deno-readme]: https://github.com/stdlib-js/math-base-special-expm1rel/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/math-base-special-expm1rel/tree/umd
[umd-readme]: https://github.com/stdlib-js/math-base-special-expm1rel/blob/umd/README.md
[esm-url]: https://github.com/stdlib-js/math-base-special-expm1rel/tree/esm
[esm-readme]: https://github.com/stdlib-js/math-base-special-expm1rel/blob/esm/README.md
[branches-url]: https://github.com/stdlib-js/math-base-special-expm1rel/blob/main/branches.md
[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/math-base-special-expm1rel/main/LICENSE
[@stdlib/math/base/special/exp]: https://www.npmjs.com/package/@stdlib/math-base-special-exp
[@stdlib/math/base/special/expm1]: https://www.npmjs.com/package/@stdlib/math-base-special-expm1