Multiply a single-precision floating-point number by an integer power of two.
npm install @stdlib/math-base-special-ldexpfWe 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]
> Multiply a [single-precision floating-point number][ieee754] by an integer power of two.
``bash`
npm install @stdlib/math-base-special-ldexpf
`javascript`
var ldexpf = require( '@stdlib/math-base-special-ldexpf' );
#### ldexpf( frac, exp )
Multiplies a [single-precision floating-point number][ieee754] by an integer power of two (i.e., x = frac * 2^exp).
`javascript
var x = ldexpf( 0.5, 3 ); // => 0.5 2^3 = 0.5 8
// returns 4.0
x = ldexpf( 4.0, -2 ); // => 4 2^(-2) = 4 (1/4)
// returns 1.0
`
If frac equals positive or negative zero, NaN, or positive or negative infinity, the function returns a value equal to frac.
`javascript
var x = ldexpf( 0.0, 20 );
// returns 0.0
x = ldexpf( -0.0, 39 );
// returns -0.0
x = ldexpf( NaN, -101 );
// returns NaN
x = ldexpf( Infinity, 11 );
// returns Infinity
x = ldexpf( -Infinity, -118 );
// returns -Infinity
`
- This function is the inverse of [frexpf][@stdlib/math/base/special/frexpf].
`javascript
var linspace = require( '@stdlib/array-base-linspace' );
var discreteUniform = require( '@stdlib/random-array-discrete-uniform' );
var ldexpf = require( '@stdlib/math-base-special-ldexpf' );
var frac = linspace( 0.0, 100.0, 10 );
var exp = discreteUniform( 100, 0, 10 );
var i;
for ( i = 0; i < frac.length; i++ ) {
console.log( 'ldexpf(%d,%d) = %d', frac[ i ], exp[ i ], ldexpf( frac[ i ], exp[ i ] ) );
}
`
*
`c`
#include "stdlib/math/base/special/ldexpf.h"
#### stdlib_base_ldexpf( frac, exp )
Multiplies a [single-precision floating-point number][ieee754] by an integer power of two (i.e., x = frac * 2^exp).
`c`
float x = stdlib_base_ldexpf( 0.5f, 3 ); // => 0.5 2^3 = 0.5 8
// returns 4.0f
The function accepts the following arguments:
- frac: [in] float input value.[in] int32_t
- exp: integer power of two.
`c`
float stdlib_base_ldexpf( const float frac, const int32_t exp );
`c
#include "stdlib/math/base/special/ldexpf.h"
#include
#include
int main( void ) {
float y;
int i;
const float frac[] = { 0.5f, 5.0f, 0.0f, 3.5f, 7.9f };
const int32_t exp[] = { 3, -2, 20, 39, 14 };
for ( i = 0; i < 5; i++ ) {
y = stdlib_base_ldexpf( frac[ i ], exp[ i ] );
printf( "ldexpf(%f, %d) = %f\n", frac[ i ], exp[ i ], y );
}
}
`
*
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-ldexpf.svg
[npm-url]: https://npmjs.org/package/@stdlib/math-base-special-ldexpf
[test-image]: https://github.com/stdlib-js/math-base-special-ldexpf/actions/workflows/test.yml/badge.svg?branch=v0.1.1
[test-url]: https://github.com/stdlib-js/math-base-special-ldexpf/actions/workflows/test.yml?query=branch:v0.1.1
[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/math-base-special-ldexpf/main.svg
[coverage-url]: https://codecov.io/github/stdlib-js/math-base-special-ldexpf?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-ldexpf/tree/deno
[deno-readme]: https://github.com/stdlib-js/math-base-special-ldexpf/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/math-base-special-ldexpf/tree/umd
[umd-readme]: https://github.com/stdlib-js/math-base-special-ldexpf/blob/umd/README.md
[esm-url]: https://github.com/stdlib-js/math-base-special-ldexpf/tree/esm
[esm-readme]: https://github.com/stdlib-js/math-base-special-ldexpf/blob/esm/README.md
[branches-url]: https://github.com/stdlib-js/math-base-special-ldexpf/blob/main/branches.md
[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/math-base-special-ldexpf/main/LICENSE
[ieee754]: https://en.wikipedia.org/wiki/IEEE_754-1985
[@stdlib/math/base/special/frexpf]: https://www.npmjs.com/package/@stdlib/math-base-special-frexpf