Package dev.nm.analysis.function.special.gamma

Class LogGamma

java.lang.Object

dev.nm.analysis.function.rn2r1.AbstractRealScalarFunction

dev.nm.analysis.function.rn2r1.univariate.AbstractUnivariateRealFunction

dev.nm.analysis.function.special.gamma.LogGamma

All Implemented Interfaces:

Function<Vector,Double>, RealScalarFunction, UnivariateRealFunction

public class LogGamma
extends AbstractUnivariateRealFunction

The log-Gamma function, \(\log (\Gamma(z))\), for positive real numbers, is the log of the Gamma function.

See Also:

• • Wikipedia: Gamma function
  • Wikipedia: Lanczos approximation

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static enum	LogGamma.Method	the available methods to compute \(\log (\Gamma(z))\)

Nested classes/interfaces inherited from interface dev.nm.analysis.function.Function

Function.EvaluationException

Constructor Summary

Constructors

Constructor	Description
LogGamma()	Construct an instance of log-Gamma.
LogGamma(LogGamma.Method method, Lanczos lanczos)	Construct an instance of log-Gamma.

Method Summary

Modifier and Type	Method	Description
double	evaluate(double x)	Evaluate the log of the Gamma function in the positive real domain.

Methods inherited from class dev.nm.analysis.function.rn2r1.univariate.AbstractUnivariateRealFunction

evaluate

Methods inherited from class dev.nm.analysis.function.rn2r1.AbstractRealScalarFunction

dimensionOfDomain, dimensionOfRange

Methods inherited from class java.lang.Object

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

Methods inherited from interface dev.nm.analysis.function.Function

dimensionOfDomain, dimensionOfRange

Constructor Details

LogGamma

public LogGamma(LogGamma.Method method,
 Lanczos lanczos)

Construct an instance of log-Gamma.

Parameters:

method - the Lanczos computation to use

lanczos - the Lanczos approximation to use

LogGamma

public LogGamma()

Construct an instance of log-Gamma.

Method Details

evaluate

public double evaluate(double x)

Evaluate the log of the Gamma function in the positive real domain.

Parameters:

x - a real number > 0

Returns:

\(\log (\Gamma(z))\)