edu.umass.cs.mallet.base.classify

Class AdaBoost

java.lang.Object

edu.umass.cs.mallet.base.classify.Classifier

edu.umass.cs.mallet.base.classify.AdaBoost

public class AdaBoost
extends Classifier

AdaBoost Robert E. Schapire. "The boosting approach to machine learning: An overview." In MSRI Workshop on Nonlinear Estimation and Classification, 2002. http://www.research.att.com/~schapire/cgi-bin/uncompress-papers/msri.ps

Author:

Andrew McCallum mccallum@cs.umass.edu

Field Summary

Fields inherited from class edu.umass.cs.mallet.base.classify.Classifier

instancePipe

Constructor Summary

Constructors

Constructor and Description
AdaBoost(Pipe instancePipe, Classifier[] weakClassifiers, double[] alphas)

Method Summary

Modifier and Type	Method and Description
Classification	classify(Instance inst)
Classification	classify(Instance inst, int numWeakClassifiersToUse) Classify the given instance using only the first numWeakClassifiersToUse classifiers trained during boosting
int	getNumWeakClassifiers() Get the number of weak classifiers in this ensemble classifier
AdaBoost	getTrimmedClassifier(int numWeakClassifiersToUse) Return an AdaBoost classifier that uses only the first numWeakClassifiersToUse weak learners.

Methods inherited from class edu.umass.cs.mallet.base.classify.Classifier

classify, classify, classify, getAccuracy, getAccuracy, getAlphabet, getF1, getF1, getF1, getF1, getInstancePipe, getLabelAlphabet, getPrecision, getPrecision, getPrecision, getPrecision, getRecall, getRecall, getRecall, getRecall, print, print

Methods inherited from class java.lang.Object

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

Constructor Detail

AdaBoost

public AdaBoost(Pipe instancePipe,
                Classifier[] weakClassifiers,
                double[] alphas)

Method Detail

getNumWeakClassifiers

public int getNumWeakClassifiers()

Get the number of weak classifiers in this ensemble classifier

getTrimmedClassifier

public AdaBoost getTrimmedClassifier(int numWeakClassifiersToUse)

Return an AdaBoost classifier that uses only the first numWeakClassifiersToUse weak learners.

The returned classifier's Pipe and weak classifiers are backed by the respective objects of this classifier, so changes to the returned classifier's Pipe and weak classifiers are reflected in this classifier, and vice versa.

classify

public Classification classify(Instance inst)

Specified by:

classify in class Classifier

classify

public Classification classify(Instance inst,
                               int numWeakClassifiersToUse)

Classify the given instance using only the first numWeakClassifiersToUse classifiers trained during boosting