@stdlib/math-base-special-log2
v0.3.1TypeScript
Binary logarithm (base 2).
0/weekUpdated yesterdayApache-2.0Unpacked: 60.4 KB
Published by The Stdlib Authors
npm install @stdlib/math-base-special-log2We 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...
Binary Logarithm
[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url]
> Evaluate the [binary logarithm][binary-logarithm].
The [binary logarithm][binary-logarithm] (logarithm with base 2) is defined for any positive real number as
Installation
``bash`
npm install @stdlib/math-base-special-log2
Usage
`javascript`
var log2 = require( '@stdlib/math-base-special-log2' );
#### log2( x )
Evaluates the [binary logarithm][binary-logarithm].
`javascript
var v = log2( 4.0 );
// returns 2.0
v = log2( 0.0 );
// returns -Infinity
v = log2( Infinity );
// returns Infinity
v = log2( NaN );
// returns NaN
`
For negative numbers, the [binary logarithm][binary-logarithm] is not defined.
`javascript`
var v = log2( -4.0 );
// returns NaN
Examples
`javascript
var discreteUniform = require( '@stdlib/random-array-discrete-uniform' );
var logEachMap = require( '@stdlib/console-log-each-map' );
var log2 = require( '@stdlib/math-base-special-log2' );
var opts = {
'dtype': 'float64'
};
var x = discreteUniform( 100, 0, 100, opts );
logEachMap( 'log2(%d) = %0.4f', x, log2 );
`
*
C APIs
$3
`c`
#include "stdlib/math/base/special/log2.h"
#### stdlib_base_log2( x )
Evaluates the binary logarithm.
`c`
double out = stdlib_base_log2( 4.0 );
// returns 2.0
The function accepts the following arguments:
- x: [in] double input value.
`c`
double stdlib_base_log2( const double x );
$3
`c
#include "stdlib/math/base/special/log2.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 );
v = stdlib_base_log2( x );
printf( "log2(%lf) = %lf\n", x, v );
}
}
`
*
See Also
- [@stdlib/math-base/special/exp2][@stdlib/math/base/special/exp2]: base 2 exponential function.
- [@stdlib/math-base/special/ln][@stdlib/math/base/special/ln]: evaluate the natural logarithm of a double-precision floating-point number.
- [@stdlib/math-base/special/log][@stdlib/math/base/special/log]: compute the base b logarithm of a double-precision floating-point number.
*
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 © 2016-2026. The Stdlib [Authors][stdlib-authors].
[npm-image]: http://img.shields.io/npm/v/@stdlib/math-base-special-log2.svg
[npm-url]: https://npmjs.org/package/@stdlib/math-base-special-log2
[test-image]: https://github.com/stdlib-js/math-base-special-log2/actions/workflows/test.yml/badge.svg?branch=v0.3.1
[test-url]: https://github.com/stdlib-js/math-base-special-log2/actions/workflows/test.yml?query=branch:v0.3.1
[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/math-base-special-log2/main.svg
[coverage-url]: https://codecov.io/github/stdlib-js/math-base-special-log2?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-log2/tree/deno
[deno-readme]: https://github.com/stdlib-js/math-base-special-log2/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/math-base-special-log2/tree/umd
[umd-readme]: https://github.com/stdlib-js/math-base-special-log2/blob/umd/README.md
[esm-url]: https://github.com/stdlib-js/math-base-special-log2/tree/esm
[esm-readme]: https://github.com/stdlib-js/math-base-special-log2/blob/esm/README.md
[branches-url]: https://github.com/stdlib-js/math-base-special-log2/blob/main/branches.md
[binary-logarithm]: https://en.wikipedia.org/wiki/Binary_logarithm
[@stdlib/math/base/special/exp2]: https://www.npmjs.com/package/@stdlib/math-base-special-exp2
[@stdlib/math/base/special/ln]: https://www.npmjs.com/package/@stdlib/math-base-special-ln
[@stdlib/math/base/special/log]: https://www.npmjs.com/package/@stdlib/math-base-special-log