Package org.mariuszgromada.math.mxparser.mathcollection

Class SpecialFunctions

java.lang.Object
org.mariuszgromada.math.mxparser.mathcollection.SpecialFunctions
public final class SpecialFunctions extends Object
SpecialFunctions - special (non-elementary functions).
Version:
4.3.0

  • Constructor Summary

    Constructors
    Constructor
    Description
    SpecialFunctions()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    static double
    beta(double x, double y)
    Beta special function
    static final double
    diGamma(double x)
    Digamma function as the logarithmic derivative of the Gamma special function
    static final double
    erf(double x)
    Calculates the error function
    static final double
    erfc(double x)
    Calculates the complementary error function.
    static final double
    erfcInv(double z)
    Calculates the complementary inverse error function evaluated at x.
    static final double
    erfInv(double x)
    Calculates the inverse error function evaluated at x.
    static double
    exponentialIntegralEi(double x)
    Exponential integral function Ei(x)
    static final double
    gamma(double x)
    Real valued Gamma function
    static double
    incompleteBeta(double a, double b, double x)
    Log Incomplete Beta special function
    static final double
    incompleteGammaLower(double s, double x)
    Incomplete lower gamma function
    static final double
    incompleteGammaUpper(double s, double x)
    Incomplete upper gamma function
    static final double
    lambertW(double x, double branch)
    Real-valued Lambert-W function approximation.
    static final double
    lanchosGamma(double x)
    Gamma function implementation based on Lanchos approximation algorithm
    static final double
    logarithmicIntegralLi(double x)
    Logarithmic integral function li(x)
    static double
    logBeta(double x, double y)
    Log Beta special function
    static double
    logGamma(double x)
    Real valued log gamma function.
    static final double
    offsetLogarithmicIntegralLi(double x)
    Offset logarithmic integral function Li(x)
    static double
    regularizedBeta(double a, double b, double x)
    Regularized incomplete Beta special function
    static final double
    regularizedGammaLowerP(double s, double x)
    Regularized lower gamma function 'P'
    static final double
    regularizedGammaUpperQ(double s, double x)
    Regularized upper gamma function 'Q'
    static final double
    sgnGamma(double x)
    Signum from the real valued gamma function.

    Methods inherited from class java.lang.Object

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

  • Constructor Details

    • SpecialFunctions

      public SpecialFunctions()

  • Method Details

    • exponentialIntegralEi

      public static double exponentialIntegralEi(double x)
      Exponential integral function Ei(x)
      Parameters:
      x - Point at which function will be evaluated.
      Returns:
      Exponential integral function Ei(x)

    • logarithmicIntegralLi

      public static final double logarithmicIntegralLi(double x)
      Logarithmic integral function li(x)
      Parameters:
      x - Point at which function will be evaluated.
      Returns:
      Logarithmic integral function li(x)

    • offsetLogarithmicIntegralLi

      public static final double offsetLogarithmicIntegralLi(double x)
      Offset logarithmic integral function Li(x)
      Parameters:
      x - Point at which function will be evaluated.
      Returns:
      Offset logarithmic integral function Li(x)

    • erf

      public static final double erf(double x)
      Calculates the error function
      Parameters:
      x - Point at which function will be evaluated.
      Returns:
      Error function erf(x)

    • erfc

      public static final double erfc(double x)
      Calculates the complementary error function.
      Parameters:
      x - Point at which function will be evaluated.
      Returns:
      Complementary error function erfc(x)

    • erfInv

      public static final double erfInv(double x)
      Calculates the inverse error function evaluated at x.
      Parameters:
      x - Point at which function will be evaluated.
      Returns:
      Inverse error function erfInv(x)

    • erfcInv

      public static final double erfcInv(double z)
      Calculates the complementary inverse error function evaluated at x.
      Parameters:
      z - Point at which function will be evaluated.
      Returns:
      Inverse of complementary inverse error function erfcInv(x)

    • gamma

      public static final double gamma(double x)
      Real valued Gamma function
      Parameters:
      x - Argument value
      Returns:
      Returns gamma function value.

    • lanchosGamma

      public static final double lanchosGamma(double x)
      Gamma function implementation based on Lanchos approximation algorithm
      Parameters:
      x - Function parameter
      Returns:
      Gamma function value (Lanchos approx).

    • logGamma

      public static double logGamma(double x)
      Real valued log gamma function.
      Parameters:
      x - Argument value
      Returns:
      Returns log value from gamma function.

    • sgnGamma

      public static final double sgnGamma(double x)
      Signum from the real valued gamma function.
      Parameters:
      x - Argument value
      Returns:
      Returns signum of the gamma(x)

    • regularizedGammaLowerP

      public static final double regularizedGammaLowerP(double s, double x)
      Regularized lower gamma function 'P'
      Parameters:
      s - Argument value
      x - Argument value
      Returns:
      Value of the regularized lower gamma function 'P'.

    • incompleteGammaLower

      public static final double incompleteGammaLower(double s, double x)
      Incomplete lower gamma function
      Parameters:
      s - Argument value
      x - Argument value
      Returns:
      Value of the incomplete lower gamma function.

    • regularizedGammaUpperQ

      public static final double regularizedGammaUpperQ(double s, double x)
      Regularized upper gamma function 'Q'
      Parameters:
      s - Argument value
      x - Argument value
      Returns:
      Value of the regularized upper gamma function 'Q'.

    • incompleteGammaUpper

      public static final double incompleteGammaUpper(double s, double x)
      Incomplete upper gamma function
      Parameters:
      s - Argument value
      x - Argument value
      Returns:
      Value of the incomplete upper gamma function.

    • diGamma

      public static final double diGamma(double x)
      Digamma function as the logarithmic derivative of the Gamma special function
      Parameters:
      x - Argument value
      Returns:
      Approximated value of the digamma function.

    • logBeta

      public static double logBeta(double x, double y)
      Log Beta special function
      Parameters:
      x - Argument value
      y - Argument value
      Returns:
      Return logBeta special function (for positive x and positive y)

    • beta

      public static double beta(double x, double y)
      Beta special function
      Parameters:
      x - Argument value
      y - Argument value
      Returns:
      Return Beta special function (for positive x and positive y)

    • incompleteBeta

      public static double incompleteBeta(double a, double b, double x)
      Log Incomplete Beta special function
      Parameters:
      a - Argument value
      b - Argument value
      x - Argument value
      Returns:
      Return incomplete Beta special function for positive a and positive b and x between 0 and 1

    • regularizedBeta

      public static double regularizedBeta(double a, double b, double x)
      Regularized incomplete Beta special function
      Parameters:
      a - Argument value
      b - Argument value
      x - Argument value
      Returns:
      Return incomplete Beta special function for positive a and positive b and x between 0 and 1

    • lambertW

      public static final double lambertW(double x, double branch)
      Real-valued Lambert-W function approximation.
      Parameters:
      x - Point at which function will be approximated
      branch - Branch id, 0 for principal branch, -1 for the other branch
      Returns:
      Principal branch for x greater or equal than -1/e, otherwise Double.NaN. Minus 1 branch for x greater or equal than -1/e and lower than 0, otherwise Double.NaN.