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Class weka.core.SpecialFunctions

java.lang.Object
    |
    +----weka.core.SpecialFunctions

public final class SpecialFunctions
extends java.lang.Object
Class implementing some mathematical functions.

Version:
$Revision: 1.4 $
Author:
Eibe Frank (eibe@cs.waikato.ac.nz)

Constructor Index

 o SpecialFunctions()
 

Method Index

 o lnFactorial(double)
Returns natural logarithm of factorial using gamma function.
 o lnGamma(double)
Returns natural logarithm of gamma function.
 o log2Binomial(double, double)
Returns base 2 logarithm of binomial coefficient using gamma function.
 o log2Multinomial(double, double[])
Returns base 2 logarithm of multinomial using gamma function.
 o main(String[])
Main method for testing this class.

Constructor Detail

 o SpecialFunctions
public SpecialFunctions()

Method Detail

 o lnFactorial
public static double lnFactorial(double x)
          Returns natural logarithm of factorial using gamma function.
Parameters:
x - the value
Returns:
natural logarithm of factorial
 o lnGamma
public static double lnGamma(double x)
          Returns natural logarithm of gamma function. Converted to java from Numerical Recipes in C.
Parameters:
x - the value
Returns:
natural logarithm of gamma function
 o log2Binomial
public static double log2Binomial(double a,
                                  double b) throws java.lang.ArithmeticException
          Returns base 2 logarithm of binomial coefficient using gamma function.
Parameters:
a - upper part of binomial coefficient
b - lower part
Returns:
the base 2 logarithm of the binominal coefficient a over b
 o log2Multinomial
public static double log2Multinomial(double a,
                                     double bs[]) throws java.lang.ArithmeticException
          Returns base 2 logarithm of multinomial using gamma function.
Parameters:
a - upper part of multinomial coefficient
bs - lower part
Returns:
multinomial coefficient of a over the bs
 o main
public static void main(java.lang.String ops[])
          Main method for testing this class.

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