dragon.ir.classification.featureselection

Class DocFrequencySelector

java.lang.Object

dragon.ir.classification.featureselection.AbstractFeatureSelector

dragon.ir.classification.featureselection.DocFrequencySelector

All Implemented Interfaces:

FeatureSelector, Serializable

public class DocFrequencySelector
extends AbstractFeatureSelector
implements Serializable

Unsupervised Feature Selector which exclude features with its document frequency less than a given threshold

Please refer the paper below for details of the algorithm.
Yang, Y. and Pedersen, J.O., "A comparative study on feature selection in text categorization," In Proceedings of International Conference on Machine Learning, 1997, pp. 412-420.

Copyright: Copyright (c) 2005

Company: IST, Drexel University

Version:

1.0

Author:

Davis Zhou

See Also:

Serialized Form

Field Summary

Fields inherited from class dragon.ir.classification.featureselection.AbstractFeatureSelector

featureMap, selectedFeatureNum

Constructor Summary

Constructors

Constructor and Description
DocFrequencySelector(int minDocFrequency)

Method Summary

Modifier and Type	Method and Description
protected int[]	getSelectedFeatures(IndexReader indexReader, DocClassSet trainingSet)
protected int[]	getSelectedFeatures(SparseMatrix doctermMatrix, DocClassSet trainingSet)

Methods inherited from class dragon.ir.classification.featureselection.AbstractFeatureSelector

getClassPrior, getSelectedFeatureNum, getTermDistribution, getTermDistribution, getTermDocFrequency, isSelected, map, setSelectedFeatures, train, train

Methods inherited from class java.lang.Object

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

Constructor Detail

DocFrequencySelector

public DocFrequencySelector(int minDocFrequency)

Method Detail

getSelectedFeatures

protected int[] getSelectedFeatures(SparseMatrix doctermMatrix,
                                    DocClassSet trainingSet)

Specified by:

getSelectedFeatures in class AbstractFeatureSelector

getSelectedFeatures

protected int[] getSelectedFeatures(IndexReader indexReader,
                                    DocClassSet trainingSet)

Specified by:

getSelectedFeatures in class AbstractFeatureSelector