spencef

Spence's function (the dilogarithm) for a single-precision floating-point number.

The dilogarithm is defined as

or also alternatively as

Installation

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

Usage

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

spencef( x )

Evaluates Spence's function (the dilogarithm) for a single-precision floating-point number.

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

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

v = spencef( NaN );
// returns NaN

For negative numbers, the dilogarithm is not defined.

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

Examples

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

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

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

C APIs

Usage

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

stdlib_base_spencef( x )

Evaluates Spence's function (the dilogarithm) for a single-precision floating-point number.

float out = stdlib_base_spencef( 3.0f );
// returns ~-1.437f

out = stdlib_base_spencef( 0.0f );
// returns ~1.645f

The function accepts the following arguments:

• x: [in] float input value.

float stdlib_base_spencef( const float x );

Examples

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

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

    float y;
    int i;
    for ( i = 0; i < 4; i++ ) {
        y = stdlib_base_spencef( x[ i ] );
        printf( "spencef(%f) = %f\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.

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Copyright

Copyright © 2016-2026. The Stdlib Authors.