Package jebl.math

Class GammaFunction

java.lang.Object
jebl.math.GammaFunction

public class GammaFunction extends Object
gamma function
Version:
$Id: GammaFunction.java 305 2006-04-26 00:22:30Z rambaut $
Author:
Korbinian Strimmer
  • Constructor Summary

    Constructors
    Constructor
    Description
     
  • Method Summary

    Modifier and Type
    Method
    Description
    static double
    incompleteGammaP(double a, double x)
    Incomplete Gamma function P(a,x) = 1-Q(a,x) (a cleanroom implementation of Numerical Recipes gammp(a,x); in Mathematica this function is 1-GammaRegularized)
    static double
    incompleteGammaP(double a, double x, double lnGammaA)
    Incomplete Gamma function P(a,x) = 1-Q(a,x) (a cleanroom implementation of Numerical Recipes gammp(a,x); in Mathematica this function is 1-GammaRegularized)
    static double
    incompleteGammaQ(double a, double x)
    Incomplete Gamma function Q(a,x) (a cleanroom implementation of Numerical Recipes gammq(a,x); in Mathematica this function is called GammaRegularized)
    static double
    lnGamma(double alpha)
    log Gamma function: ln(gamma(alpha)) for alpha>0, accurate to 10 decimal places

    Methods inherited from class java.lang.Object

    equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
  • Constructor Details

    • GammaFunction

      public GammaFunction()
  • Method Details

    • lnGamma

      public static double lnGamma(double alpha)
      log Gamma function: ln(gamma(alpha)) for alpha>0, accurate to 10 decimal places
      Parameters:
      alpha - argument
    • incompleteGammaQ

      public static double incompleteGammaQ(double a, double x)
      Incomplete Gamma function Q(a,x) (a cleanroom implementation of Numerical Recipes gammq(a,x); in Mathematica this function is called GammaRegularized)
      Parameters:
      a - parameter
      x - argument
      Returns:
      function value
    • incompleteGammaP

      public static double incompleteGammaP(double a, double x)
      Incomplete Gamma function P(a,x) = 1-Q(a,x) (a cleanroom implementation of Numerical Recipes gammp(a,x); in Mathematica this function is 1-GammaRegularized)
      Parameters:
      a - parameter
      x - argument
      Returns:
      function value
    • incompleteGammaP

      public static double incompleteGammaP(double a, double x, double lnGammaA)
      Incomplete Gamma function P(a,x) = 1-Q(a,x) (a cleanroom implementation of Numerical Recipes gammp(a,x); in Mathematica this function is 1-GammaRegularized)
      Parameters:
      a - parameter
      x - argument
      lnGammaA - precomputed lnGamma(a)
      Returns:
      function value