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lnf

Evaluate the natural logarithm of a single-precision floating-point number.

Installation

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

Alternatively,

• To load the package in a website via a script tag without installation and bundlers, use the ES Module available on the esm branch (see README).
• If you are using Deno, visit the deno branch (see README for usage intructions).
• For use in Observable, or in browser/node environments, use the Universal Module Definition (UMD) build available on the umd branch (see README).

The branches.md file summarizes the available branches and displays a diagram illustrating their relationships.

To view installation and usage instructions specific to each branch build, be sure to explicitly navigate to the respective README files on each branch, as linked to above.

Usage

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

lnf( x )

Evaluates the natural logarithm of a single-precision floating-point number.

var v = lnf( 4.0 );
// returns ~1.386

v = lnf( 0.0 );
// returns -Infinity

v = lnf( Infinity );
// returns Infinity

v = lnf( NaN );
// returns NaN

For negative numbers, the natural logarithm is not defined.

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

Examples

var randu = require( '@stdlib/random-base-randu' );
var round = require( '@stdlib/math-base-special-round' );
var lnf = require( '@stdlib/math-base-special-lnf' );

var x;
var i;

for ( i = 0; i < 100; i++ ) {
    x = round( randu() * 100.0 );
    console.log( 'lnf(%d) = %d', x, lnf( x ) );
}

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C APIs

Usage

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

stdlib_base_lnf( x )

Evaluates the natural logarithm of a single-precision floating-point number.

float v = stdlib_base_lnf( 2.0f );
// returns ~0.693f

The function accepts the following arguments:

• x: [in] float input value.

float stdlib_base_lnf( const float x );

Examples

#include "stdlib/math/base/special/lnf.h"
#include <stdlib.h>
#include <stdio.h>

int main( void ) {
    float out;
    float x;
    int i;

    for ( i = 0; i < 100; i++ ) {
        x = ( (float)rand() / (float)RAND_MAX ) * 100.0f;
        out = stdlib_base_lnf( x );
        printf( "lnf(%f) = %f\n", x, out );
    }
}

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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.

Community

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Copyright

Copyright © 2016-2024. The Stdlib Authors.