log1pf

Evaluate the natural logarithm of 1+x as a single‐precision floating-point number.

Installation

npm install @stdlib/math-base-special-log1pf

Usage

var log1pf = require( '@stdlib/math-base-special-log1pf' );

log1pf( x )

Evaluates the natural logarithm of 1+x as a single‐precision floating-point number.

var v = log1pf( 4.0 );
// returns ~1.609

v = log1pf( -1.0 );
// returns -Infinity

v = log1pf( Infinity );
// returns Infinity

v = log1pf( 0.0 );
// returns 0.0

v = log1pf( -0.0 );
// returns -0.0

v = log1pf( NaN );
// returns NaN

For x < -1, the function returns NaN, as the natural logarithm is not defined for negative numbers.

var v = log1pf( -2.0 );
// returns NaN

Examples

var uniform = require( '@stdlib/random-array-uniform' );
var logEachMap = require( '@stdlib/console-log-each-map' );
var log1pf = require( '@stdlib/math-base-special-log1pf' );

var opts = {
    'dtype': 'float32'
};
var x = uniform( 100, 0.0, 100.0, opts );

logEachMap( 'log1pf(%0.4f) = %0.4f', x, log1pf );

C APIs

Usage

#include "stdlib/math/base/special/log1pf.h"

stdlib_base_log1pf( x )

Evaluates the natural logarithm of 1+x as a single‐precision floating-point number.

float out = stdlib_base_log1pf( 4.0f );
// returns ~1.609f

out = stdlib_base_log1pf( -1.0f );
// returns -Infinity

The function accepts the following arguments:

• x: [in] float input value.

float stdlib_base_log1pf( const float x );

Examples

#include "stdlib/math/base/special/log1pf.h"
#include <stdlib.h>
#include <stdio.h>

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

    for ( i = 0; i < 100; i++ ) {
        x = ( (float)rand() / (float)RAND_MAX ) * 100.0f;
        v = stdlib_base_log1pf( x );
        printf( "log1pf(%f) = %f\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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Copyright

Copyright © 2016-2026. The Stdlib Authors.