weka.classifiers.trees.j48
Class GainRatioSplitCrit

java.lang.Object
  weka.classifiers.trees.j48.SplitCriterion
      weka.classifiers.trees.j48.EntropyBasedSplitCrit
          weka.classifiers.trees.j48.GainRatioSplitCrit

All Implemented Interfaces:

java.io.Serializable

public final class GainRatioSplitCrit

extends EntropyBasedSplitCrit

Class for computing the gain ratio for a given distribution.

Version:

$Revision: 1.5 $

Author:

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

See Also:

Serialized Form

Field Summary

Fields inherited from class weka.classifiers.trees.j48.EntropyBasedSplitCrit

log2

Constructor Summary

GainRatioSplitCrit()

Method Summary

double	splitCritValue(Distribution bags) This method is a straightforward implementation of the gain ratio criterion for the given distribution.
double	splitCritValue(Distribution bags, double totalnoInst, double numerator) This method computes the gain ratio in the same way C4.5 does.
private double	splitEnt(Distribution bags, double totalnoInst) Help method for computing the split entropy.

Methods inherited from class weka.classifiers.trees.j48.EntropyBasedSplitCrit

logFunc, newEnt, oldEnt, splitEnt

Methods inherited from class weka.classifiers.trees.j48.SplitCriterion

splitCritValue, splitCritValue, splitCritValue

Methods inherited from class java.lang.Object

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

Constructor Detail

GainRatioSplitCrit

public GainRatioSplitCrit()

Method Detail

splitCritValue

public final double splitCritValue(Distribution bags)

This method is a straightforward implementation of the gain ratio criterion for the given distribution.

Overrides:

splitCritValue in class SplitCriterion

Returns:

value of splitting criterion. 0 by default

splitCritValue

public final double splitCritValue(Distribution bags,
                                   double totalnoInst,
                                   double numerator)

This method computes the gain ratio in the same way C4.5 does.

Parameters:

bags - the distribution

totalnoInst - the weight of ALL instances

numerator - the info gain

splitEnt

private final double splitEnt(Distribution bags,
                              double totalnoInst)

Help method for computing the split entropy.