README

log1p

$NPM version$ $Build Status$ $Coverage Status$ $dependencies$

Evaluate the natural logarithm of 1+x.

Installation

npm install @stdlib/math-base-special-log1p

Usage

var log1p = require( '@stdlib/math-base-special-log1p' );

log1p( x )

Evaluates the natural logarithm of 1+x.

var v = log1p( 4.0 );
// returns ~1.609

v = log1p( -1.0 );
// returns -Infinity

v = log1p( Infinity );
// returns Infinity

v = log1p( 0.0 );
// returns 0.0

v = log1p( -0.0 );
// returns -0.0

v = log1p( NaN );
// returns NaN

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

var v = log1p( -2.0 );
// returns NaN

Examples

var randu = require( '@stdlib/random-base-randu' );
var round = require( '@stdlib/math-base-special-round' );
var log1p = require( '@stdlib/math-base-special-log1p' );

var x;
var i;

for ( i = 0; i < 100; i++ ) {
    x = round( randu() * 100.0 );
    console.log( log1p( x ) );
}

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

License

See LICENSE.

@stdlib/math-base-special-log1p

Usage no npm install needed!