weka.core

Class SpecialFunctions

java.lang.Object

weka.core.SpecialFunctions

All Implemented Interfaces:

RevisionHandler

public final class SpecialFunctions
extends Object
implements RevisionHandler

Class implementing some mathematical functions.

Version:

$Revision: 8034 $

Author:

Eibe Frank (eibe@cs.waikato.ac.nz)

Constructor Summary

Constructors

Constructor and Description
SpecialFunctions()

Method Summary

Modifier and Type	Method and Description
String	getRevision() Returns the revision string.
static double	lnFactorial(double x) Returns natural logarithm of factorial using gamma function.
static double	log2Binomial(double a, double b) Returns base 2 logarithm of binomial coefficient using gamma function.
static double	log2Multinomial(double a, double[] bs) Returns base 2 logarithm of multinomial using gamma function.
static void	main(String[] ops) Main method for testing this class.

Methods inherited from class java.lang.Object

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

Constructor Detail

SpecialFunctions

public SpecialFunctions()

Method Detail

lnFactorial

public static double lnFactorial(double x)

Returns natural logarithm of factorial using gamma function.

Parameters:

x - the value

Returns:

natural logarithm of factorial

log2Binomial

public static double log2Binomial(double a,
                                  double b)

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

log2Multinomial

public static double log2Multinomial(double a,
                                     double[] bs)

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

getRevision

public String getRevision()

Returns the revision string.

Specified by:

getRevision in interface RevisionHandler

Returns:

the revision

main

public static void main(String[] ops)

Main method for testing this class.