@stdlib/math-base-special-spence NPM

spence

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Spence's function, also known as the dilogarithm.

The dilogarithm is defined as

or also alternatively as

Installation

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

Usage

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

spence( x )

Evaluates Spence's function, which is alternatively known as the dilogarithm.

var v = spence( 3.0 );
// returns ~-1.437

v = spence( 0.0 );
// returns ~1.645

v = spence( NaN );
// returns NaN

For negative numbers, the dilogarithm is not defined.

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

Examples

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

var x;
var i;

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

C APIs

Usage

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

stdlib_base_spence( x )

Evaluates Spence's function, which is alternatively known as the dilogarithm.

double out = stdlib_base_spence( 3.0 );
// returns ~-1.437

out = stdlib_base_spence( 0.0 );
// returns ~1.645

The function accepts the following arguments:

x: [in] double input value.

double stdlib_base_spence( const double x );

Examples

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

int main( void ) {
    const double x[] = { 3.0, 9.0, 0.0, -10.0 };

    double y;
    int i;
    for ( i = 0; i < 4; i++ ) {
        y = stdlib_base_spence( x[ i ] );
        printf( "spence(%lf) = %lf\n", x[ i ], y );
    }
}

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.