cc.mallet.classify
Class DecisionTreeTrainer

java.lang.Object
  cc.mallet.classify.ClassifierTrainer<DecisionTree>
      cc.mallet.classify.DecisionTreeTrainer

All Implemented Interfaces:

Boostable

public class DecisionTreeTrainer
extends ClassifierTrainer<DecisionTree>
implements Boostable

A decision tree learner, roughly ID3, but only to a fixed given depth in all branches. Does not yet implement splitting of continuous-valued features, but it should in the future. Currently a feature is considered "present" if it has positive value. ftp://ftp.cs.cmu.edu/project/jair/volume4/quinlan96a.ps Only set up for conveniently learning decision stubs: there is no pruning or good stopping rule. Currently only stop by reaching a maximum depth.

Author:

Andrew McCallum mccallum@cs.umass.edu

Nested Class Summary

static class

DecisionTreeTrainer.Factory

Nested classes/interfaces inherited from class cc.mallet.classify.ClassifierTrainer

ClassifierTrainer.ByActiveLearning<C extends Classifier>, ClassifierTrainer.ByIncrements<C extends Classifier>, ClassifierTrainer.ByInstanceIncrements<C extends Classifier>, ClassifierTrainer.ByOptimization<C extends Classifier>

Field Summary

static int	DEFAULT_MAX_DEPTH
static double	DEFAULT_MIN_INFO_GAIN_SPLIT

Fields inherited from class cc.mallet.classify.ClassifierTrainer

finishedTraining, validationSet

Constructor Summary

DecisionTreeTrainer()

DecisionTreeTrainer(int maxDepth)

Method Summary

DecisionTree	getClassifier()
boolean	isFinishedTraining()
DecisionTreeTrainer	setMaxDepth(int maxDepth)
DecisionTreeTrainer	setMinInfoGainSplit(double m)
protected void	splitTree(DecisionTree.Node node, FeatureSelection selectedFeatures, int depth)
DecisionTree	train(InstanceList trainingList)

Methods inherited from class cc.mallet.classify.ClassifierTrainer

getValidationInstances, setValidationInstances

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_MAX_DEPTH

public static final int DEFAULT_MAX_DEPTH

See Also:

Constant Field Values

DEFAULT_MIN_INFO_GAIN_SPLIT

public static final double DEFAULT_MIN_INFO_GAIN_SPLIT

See Also:

Constant Field Values

Constructor Detail

DecisionTreeTrainer

public DecisionTreeTrainer(int maxDepth)

DecisionTreeTrainer

public DecisionTreeTrainer()

Method Detail

setMaxDepth

public DecisionTreeTrainer setMaxDepth(int maxDepth)

setMinInfoGainSplit

public DecisionTreeTrainer setMinInfoGainSplit(double m)

isFinishedTraining

public boolean isFinishedTraining()

Overrides:

isFinishedTraining in class ClassifierTrainer<DecisionTree>

getClassifier

public DecisionTree getClassifier()

Specified by:

getClassifier in class ClassifierTrainer<DecisionTree>

train

public DecisionTree train(InstanceList trainingList)

Specified by:

train in class ClassifierTrainer<DecisionTree>

splitTree

protected void splitTree(DecisionTree.Node node,
                         FeatureSelection selectedFeatures,
                         int depth)