@stdlib/math-base-special-ln

About stdlib...

We 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!

ln

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

Installation

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

Usage

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

ln( x )

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

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

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

v = ln( Infinity );
// returns Infinity

v = ln( NaN );
// returns NaN

For negative numbers, the natural logarithm is not defined.

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

Examples

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

var x;
var i;

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

---

C APIs

Usage

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

stdlib_base_ln( x )

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

double v = stdlib_base_ln( 2.0 );
// returns ~0.693

The function accepts the following arguments:

• x: [in] double input value.

double stdlib_base_ln( const double x );

Examples

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

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

    for ( i = 0; i < 100; i++ ) {
        x = ( (double)rand() / (double)RAND_MAX ) * 100.0;
        out = stdlib_base_ln( x );
        printf( "ln(%lf) = %lf\n", x, out );
    }
}

---

See Also

• @stdlib/math-base/special/exp: natural exponential function.
• @stdlib/math-base/special/log10: common logarithm (base ten).
• @stdlib/math-base/special/log1p: evaluate the natural logarithm of 1+x.
• @stdlib/math-base/special/log2: binary logarithm (base 2).

---

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

---

Copyright

Copyright © 2016-2024. The Stdlib Authors.