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Gamma Scaled Lanczos Sum
Calculate a scaled Lanczos sum for the approximation of the gamma function.
Installation
npm install @stdlib/math-base-special-gamma-lanczos-sum-expg-scaled
Usage
var gammaLanczosSumExpGScaled = require( '@stdlib/math-base-special-gamma-lanczos-sum-expg-scaled' );
gammaLanczosSumExpGScaled( x )
Calculates the Lanczos sum for the approximation of the gamma function (scaled by exp(-g)
, where g = 10.900511
).
var v = gammaLanczosSumExpGScaled( 4.0 );
v = gammaLanczosSumExpGScaled( -1.5 );
v = gammaLanczosSumExpGScaled( -0.5 );
v = gammaLanczosSumExpGScaled( 0.5 );
v = gammaLanczosSumExpGScaled( 0.0 );
v = gammaLanczosSumExpGScaled( NaN );
Examples
var linspace = require( '@stdlib/array-base-linspace' );
var gammaLanczosSumExpGScaled = require( '@stdlib/math-base-special-gamma-lanczos-sum-expg-scaled' );
var x = linspace( -10.0, 10.0, 100 );
var i;
for ( i = 0; i < x.length; i++ ) {
console.log( 'x: %d, f(x): %d', x[ i ], gammaLanczosSumExpGScaled( x[ i ] ) );
}
C APIs
Usage
#include "stdlib/math/base/special/gamma_lanczos_sum_expg_scaled.h"
stdlib_base_gamma_lanczos_sum_expg_scaled( x )
Calculates the Lanczos sum for the approximation of the gamma function (scaled by exp(-g)
, where g = 10.900511
).
double out = stdlib_base_gamma_lanczos_sum_expg_scaled( 4.0 );
out = stdlib_base_gamma_lanczos_sum_expg_scaled( -1.5 );
The function accepts the following arguments:
- x:
[in] double
input value.
double stdlib_base_gamma_lanczos_sum_expg_scaled( const double x );
Examples
#include "stdlib/math/base/special/gamma_lanczos_sum_expg_scaled.h"
#include <stdlib.h>
#include <stdio.h>
int main( void ) {
const double x[] = { 4.0, -1.5, -0.5, 0.5 };
double y;
int i;
for ( i = 0; i < 4; i++ ) {
y = stdlib_base_gamma_lanczos_sum_expg_scaled( x[ i ] );
printf( "gamma_lanczos_sum_expg_scaled(%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.
Copyright
Copyright © 2016-2024. The Stdlib Authors.
0.3.0 (2024-07-27)
<section class="features">
Features
e8f94d2
- add C implementation for math/base/special/gamma-lanczos-sum-expg-scaled
</section>
<!-- /.features -->
<section class="commits">
Commits
<details>
b4cde28
- docs: fix function name (#2580) (by Gunj Joshi)a258a50
- chore: update package meta data (#2087) (by stdlib-bot, Philipp Burckhardt)b6968e0
- docs: fix descriptions (by Athan Reines)e8f94d2
- feat: add C implementation for math/base/special/gamma-lanczos-sum-expg-scaled
(by Gunj Joshi, Philipp Burckhardt)
</details>
</section>
<!-- /.commits -->
<section class="contributors">
Contributors
A total of 3 people contributed to this release. Thank you to the following contributors:
- Athan Reines
- Gunj Joshi
- Philipp Burckhardt
</section>
<!-- /.contributors -->
</section>
<!-- /.release -->
<section class="release" id="v0.2.1">