weka.classifiers.bayes.net.search.local

Class LAGDHillClimber

java.lang.Object

weka.classifiers.bayes.net.search.SearchAlgorithm

weka.classifiers.bayes.net.search.local.LocalScoreSearchAlgorithm

weka.classifiers.bayes.net.search.local.HillClimber

weka.classifiers.bayes.net.search.local.LAGDHillClimber

All Implemented Interfaces:

java.io.Serializable, OptionHandler, RevisionHandler

public class LAGDHillClimber
extends HillClimber

This Bayes Network learning algorithm uses a Look Ahead Hill Climbing algorithm called LAGD Hill Climbing. Unlike Greedy Hill Climbing it doesn't calculate a best greedy operation (adding, deleting or reversing an arc) but a sequence of nrOfLookAheadSteps operations, which leads to a network structure whose score is most likely higher in comparison to the network obtained by performing a sequence of nrOfLookAheadSteps greedy operations. The search is not restricted by an order on the variables (unlike K2). The difference with B and B2 is that this hill climber also considers arrows part of the naive Bayes structure for deletion.

Valid options are:

 -L <nr of look ahead steps>
  Look Ahead Depth

 -G <nr of good operations>
  Nr of Good Operations

 -P <nr of parents>
  Maximum number of parents

 -R
  Use arc reversal operation.
  (default false)

 -N
  Initial structure is empty (instead of Naive Bayes)

 -mbc
  Applies a Markov Blanket correction to the network structure, 
  after a network structure is learned. This ensures that all 
  nodes in the network are part of the Markov blanket of the 
  classifier node.

 -S [BAYES|MDL|ENTROPY|AIC|CROSS_CLASSIC|CROSS_BAYES]
  Score type (BAYES, BDeu, MDL, ENTROPY and AIC)

Version:

$Revision: 1.7 $

Author:

Manuel Neubach

See Also:

Serialized Form

Field Summary

Fields inherited from class weka.classifiers.bayes.net.search.local.LocalScoreSearchAlgorithm

TAGS_SCORE_TYPE

Constructor Summary

Constructors

Constructor and Description
LAGDHillClimber()

Method Summary

Modifier and Type	Method and Description
int	getMaxNrOfParents() Gets the max number of parents.
int	getNrOfGoodOperations() Gets the number of "good operations"
int	getNrOfLookAheadSteps() Gets the number of look-ahead steps
java.lang.String[]	getOptions() Gets the current settings of the search algorithm.
java.lang.String	getRevision() Returns the revision string.
java.lang.String	globalInfo() This will return a string describing the search algorithm.
java.util.Enumeration	listOptions() Returns an enumeration describing the available options.
java.lang.String	nrOfGoodOperationsTipText()
java.lang.String	nrOfLookAheadStepsTipText()
void	setMaxNrOfParents(int nMaxNrOfParents) Sets the max number of parents
void	setNrOfGoodOperations(int nNrOfGoodOperations) Sets the number of "good operations"
void	setNrOfLookAheadSteps(int nNrOfLookAheadSteps) Sets the number of look-ahead steps
void	setOptions(java.lang.String[] options) Parses a given list of options.

Methods inherited from class weka.classifiers.bayes.net.search.local.HillClimber

getInitAsNaiveBayes, getUseArcReversal, setInitAsNaiveBayes, setUseArcReversal, useArcReversalTipText

Methods inherited from class weka.classifiers.bayes.net.search.local.LocalScoreSearchAlgorithm

buildStructure, calcNodeScore, calcScoreWithExtraParent, calcScoreWithMissingParent, getMarkovBlanketClassifier, getScoreType, logScore, markovBlanketClassifierTipText, scoreTypeTipText, setMarkovBlanketClassifier, setScoreType

Methods inherited from class weka.classifiers.bayes.net.search.SearchAlgorithm

initAsNaiveBayesTipText, maxNrOfParentsTipText, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

LAGDHillClimber

public LAGDHillClimber()

Method Detail

setMaxNrOfParents

public void setMaxNrOfParents(int nMaxNrOfParents)

Sets the max number of parents

Overrides:

setMaxNrOfParents in class HillClimber

Parameters:

nMaxNrOfParents - the max number of parents

getMaxNrOfParents

public int getMaxNrOfParents()

Gets the max number of parents.

Overrides:

getMaxNrOfParents in class HillClimber

Returns:

the max number of parents

setNrOfLookAheadSteps

public void setNrOfLookAheadSteps(int nNrOfLookAheadSteps)

Sets the number of look-ahead steps

Parameters:

nNrOfLookAheadSteps - the number of look-ahead steps

getNrOfLookAheadSteps

public int getNrOfLookAheadSteps()

Gets the number of look-ahead steps

Returns:

the number of look-ahead step

setNrOfGoodOperations

public void setNrOfGoodOperations(int nNrOfGoodOperations)

Sets the number of "good operations"

Parameters:

nNrOfGoodOperations - the number of "good operations"

getNrOfGoodOperations

public int getNrOfGoodOperations()

Gets the number of "good operations"

Returns:

the number of "good operations"

listOptions

public java.util.Enumeration listOptions()

Returns an enumeration describing the available options.

Specified by:

listOptions in interface OptionHandler

Overrides:

listOptions in class HillClimber

Returns:

an enumeration of all the available options.

setOptions

public void setOptions(java.lang.String[] options)
                throws java.lang.Exception

Parses a given list of options. Valid options are:

Valid options are:

 -L <nr of look ahead steps>
  Look Ahead Depth

 -G <nr of good operations>
  Nr of Good Operations

 -P <nr of parents>
  Maximum number of parents

 -R
  Use arc reversal operation.
  (default false)

 -N
  Initial structure is empty (instead of Naive Bayes)

 -mbc
  Applies a Markov Blanket correction to the network structure, 
  after a network structure is learned. This ensures that all 
  nodes in the network are part of the Markov blanket of the 
  classifier node.

 -S [BAYES|MDL|ENTROPY|AIC|CROSS_CLASSIC|CROSS_BAYES]
  Score type (BAYES, BDeu, MDL, ENTROPY and AIC)

Specified by:

setOptions in interface OptionHandler

Overrides:

setOptions in class HillClimber

Parameters:

options - the list of options as an array of strings

Throws:

java.lang.Exception - if an option is not supported

getOptions

public java.lang.String[] getOptions()

Gets the current settings of the search algorithm.

Specified by:

getOptions in interface OptionHandler

Overrides:

getOptions in class HillClimber

Returns:

an array of strings suitable for passing to setOptions

globalInfo

public java.lang.String globalInfo()

This will return a string describing the search algorithm.

Overrides:

globalInfo in class HillClimber

Returns:

The string.

nrOfLookAheadStepsTipText

public java.lang.String nrOfLookAheadStepsTipText()

Returns:

a string to describe the Number of Look Ahead Steps option.

nrOfGoodOperationsTipText

public java.lang.String nrOfGoodOperationsTipText()

Returns:

a string to describe the Number of Good Operations option.

getRevision

public java.lang.String getRevision()

Returns the revision string.

Specified by:

getRevision in interface RevisionHandler

Overrides:

getRevision in class HillClimber

Returns:

the revision