Package org.apache.commons.numbers.gamma

Class LogGamma

java.lang.Object

org.apache.commons.numbers.gamma.LogGamma

public class LogGamma
extends java.lang.Object

Function \( \ln \Gamma(x) \). Class is immutable.

Constructor Summary

Constructors

Constructor	Description
LogGamma()

Method Summary

Modifier and Type	Method	Description
static double	value(double x)	Computes the function \( \ln \Gamma(x) \) for x >= 0.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

LogGamma

public LogGamma()

Method Details

value

public static double value(double x)

Computes the function \( \ln \Gamma(x) \) for x >= 0. For x <= 8, the implementation is based on the double precision implementation in the NSWC Library of Mathematics Subroutines, DGAMLN. For x >= 8, the implementation is based on

• Gamma Function, equation (28).
• Lanczos Approximation, equations (1) through (5).
• Paul Godfrey, A note on the computation of the convergent Lanczos complex Gamma approximation

Parameters:

x - Argument.

Returns:

\( \ln \Gamma(x) \), or NaN if x <= 0.