moa.classifiers.core.splitcriteria

Class InfoGainSplitCriterion

java.lang.Object

moa.AbstractMOAObject

moa.options.AbstractOptionHandler

moa.classifiers.core.splitcriteria.InfoGainSplitCriterion

All Implemented Interfaces:

Serializable, SplitCriterion, MOAObject, OptionHandler

Direct Known Subclasses:

InfoGainSplitCriterionMultilabel

public class InfoGainSplitCriterion
extends AbstractOptionHandler
implements SplitCriterion

Class for computing splitting criteria using information gain with respect to distributions of class values. The split criterion is used as a parameter on decision trees and decision stumps.

Version:

$Revision: 7 $

Author:

Richard Kirkby (rkirkby@cs.waikato.ac.nz)

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
FloatOption	minBranchFracOption

Fields inherited from class moa.options.AbstractOptionHandler

classOptionNamesToPreparedObjects, options

Constructor Summary

Constructors

Constructor and Description
InfoGainSplitCriterion()

Method Summary

Methods

Modifier and Type	Method and Description
static double	computeEntropy(double[] dist)
static double	computeEntropy(double[][] dists)
void	getDescription(StringBuilder sb, int indent) Returns a string representation of this object.
double	getMeritOfSplit(double[] preSplitDist, double[][] postSplitDists) Computes the merit of splitting for a given ditribution before the split and after it.
double	getRangeOfMerit(double[] preSplitDist) Computes the range of splitting merit
static int	numSubsetsGreaterThanFrac(double[][] distributions, double minFrac)
protected void	prepareForUseImpl(TaskMonitor monitor, ObjectRepository repository) This method describes the implementation of how to prepare this object for use.

Methods inherited from class moa.options.AbstractOptionHandler

copy, discoverOptionsViaReflection, getCLICreationString, getOptions, getPreparedClassOption, getPreparedClassOption, getPurposeString, prepareClassOptions, prepareForUse, prepareForUse

Methods inherited from class moa.AbstractMOAObject

copy, measureByteSize, measureByteSize, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface moa.options.OptionHandler

copy, getCLICreationString, getOptions, getPurposeString, prepareForUse, prepareForUse

Methods inherited from interface moa.MOAObject

measureByteSize

Field Detail

minBranchFracOption

public FloatOption minBranchFracOption

Constructor Detail

InfoGainSplitCriterion

public InfoGainSplitCriterion()

Method Detail

getMeritOfSplit

public double getMeritOfSplit(double[] preSplitDist,
                     double[][] postSplitDists)

Description copied from interface: SplitCriterion

Computes the merit of splitting for a given ditribution before the split and after it.

Specified by:

getMeritOfSplit in interface SplitCriterion

Parameters:

preSplitDist - the class distribution before the split

Returns:

value of the merit of splitting

getRangeOfMerit

public double getRangeOfMerit(double[] preSplitDist)

Description copied from interface: SplitCriterion

Computes the range of splitting merit

Specified by:

getRangeOfMerit in interface SplitCriterion

Parameters:

preSplitDist - the class distribution before the split

Returns:

value of the range of splitting merit

computeEntropy

public static double computeEntropy(double[] dist)

computeEntropy

public static double computeEntropy(double[][] dists)

numSubsetsGreaterThanFrac

public static int numSubsetsGreaterThanFrac(double[][] distributions,
                            double minFrac)

getDescription

public void getDescription(StringBuilder sb,
                  int indent)

Description copied from interface: MOAObject

Returns a string representation of this object. Used in AbstractMOAObject.toString to give a string representation of the object.

Specified by:

getDescription in interface MOAObject

Parameters:

sb - the stringbuilder to add the description

indent - the number of characters to indent

prepareForUseImpl

protected void prepareForUseImpl(TaskMonitor monitor,
                     ObjectRepository repository)

Description copied from class: AbstractOptionHandler

This method describes the implementation of how to prepare this object for use. All classes that extends this class have to implement prepareForUseImpl and not prepareForUse since prepareForUse calls prepareForUseImpl.

Specified by:

prepareForUseImpl in class AbstractOptionHandler

Parameters:

monitor - the TaskMonitor to use

repository - the ObjectRepository to use