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  • License Apache-2.0

Binary logarithm (base 2).

Package Exports

  • @stdlib/math-base-special-log2
  • @stdlib/math-base-special-log2/dist
  • @stdlib/math-base-special-log2/dist/index.js
  • @stdlib/math-base-special-log2/lib/index.js

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (@stdlib/math-base-special-log2) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

About stdlib...

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Binary Logarithm

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Evaluate the binary logarithm.

The binary logarithm (logarithm with base 2) is defined for any positive real number as

Equation for the binary logarithm.

Installation

npm install @stdlib/math-base-special-log2

Usage

var log2 = require( '@stdlib/math-base-special-log2' );

log2( x )

Evaluates the binary logarithm.

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 is not defined.

var v = log2( -4.0 );
// returns NaN

Examples

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

Usage

#include "stdlib/math/base/special/log2.h"

stdlib_base_log2( x )

Evaluates the binary logarithm.

double out = stdlib_base_log2( 4.0 );
// returns 2.0

The function accepts the following arguments:

  • x: [in] double input value.
double stdlib_base_log2( const double x );

Examples

#include "stdlib/math/base/special/log2.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_log2( x );
        printf( "log2(%lf) = %lf\n", x, v );
    }
}

Notice

This package is part of 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, see the main project repository.

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