de.jstacs.classifier
Class MappingClassifier

java.lang.Object
  de.jstacs.classifier.AbstractClassifier
      de.jstacs.classifier.AbstractScoreBasedClassifier
          de.jstacs.classifier.MappingClassifier

All Implemented Interfaces:

Storable, Cloneable

public class MappingClassifier
extends AbstractScoreBasedClassifier

This class allows the user to train the classifier on a given number of classes and to evaluate the classifier on a smaller number of classes by mapping classes together. For instance the user has a classifier for 3 classes, but likes to evaluate whether the classifier is able to discriminate between class 1 and class 2 and 3. This is a good example where to use this class. The user has to create its 3-class-classifier, create an instance of this class using its classifier, map the test samples together ( mapSample(Sample[])) and invoke AbstractClassifier.evaluate(MeasureParameters, boolean, Sample...) with these mapped sample.

Author:

Jens Keilwagen

Nested Class Summary

Nested classes/interfaces inherited from class de.jstacs.classifier.AbstractScoreBasedClassifier

AbstractScoreBasedClassifier.DoubleTableResult

Constructor Summary

MappingClassifier(AbstractScoreBasedClassifier classifier, int[] mapping)
The main constructor.

MappingClassifier(StringBuffer representation)
This is the constructor for the interface Storable.

Method Summary

protected void	extractFurtherClassifierInfosFromXML(StringBuffer xml) Extracts further information of a classifier from an XML representation.
CategoricalResult[]	getClassifierAnnotation() Returns an array of Results of dimension AbstractClassifier.getNumberOfClasses() that contains information about the classifier and for each class.
protected StringBuffer	getFurtherClassifierInfos() This method returns further information of a classifier as a StringBuffer.
String	getInstanceName() Returns a short description of the classifier.
NumericalResultSet	getNumericalCharacteristics() Returns the subset of numerical values that are also returned by AbstractClassifier.getCharacteristics().
protected double	getScore(Sequence seq, int i, boolean check) This method returns the score for a given sequence and a given class.
protected String	getXMLTag() Returns the String that is used as tag for the XML representation.
boolean	isTrained() This method gives information about the state of the classifier.
Sample[]	mapSample(Sample[] s) This method maps the samples to the internal classes.
void	train(Sample[] s, double[][] weights) This method trains a classifier over an array of weighted Samples.

Methods inherited from class de.jstacs.classifier.AbstractScoreBasedClassifier

check, check, classify, classify, clone, createDefaultClassWeights, getClassWeight, getClassWeights, getNumberOfClasses, getPValue, getPValue, getResults, getScore, getScores, setClassWeights, setThresholdClassWeights, test

Methods inherited from class de.jstacs.classifier.AbstractClassifier

classify, evaluate, evaluateAll, getAlphabetContainer, getCharacteristics, getClassificationRate, getLength, getMeasuresForEvaluate, getMeasuresForEvaluateAll, setNewAlphabetContainerInstance, toXML, train

Methods inherited from class java.lang.Object

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

Constructor Detail

MappingClassifier

public MappingClassifier(AbstractScoreBasedClassifier classifier,
                         int[] mapping)
                  throws CloneNotSupportedException

The main constructor.

Parameters:

classifier - the internal used classifier

mapping - the mapping from the classes of the internal classifier to the classes of this classifier

Throws:

CloneNotSupportedException - if something went wrong while cloning the classifier

MappingClassifier

public MappingClassifier(StringBuffer representation)
                  throws NonParsableException

This is the constructor for the interface Storable.

Parameters:

representation - the XML representation

Throws:

NonParsableException - if the representation could not be parsed.

Method Detail

extractFurtherClassifierInfosFromXML

protected void extractFurtherClassifierInfosFromXML(StringBuffer xml)
                                             throws NonParsableException

Description copied from class: AbstractClassifier

Extracts further information of a classifier from an XML representation. This method is used by the method AbstractClassifier.fromXML(StringBuffer) and should not be made public.

Overrides:

extractFurtherClassifierInfosFromXML in class AbstractScoreBasedClassifier

Parameters:

xml - XML representation

Throws:

NonParsableException - if the information could not be parsed out of the StringBuffer

getFurtherClassifierInfos

protected StringBuffer getFurtherClassifierInfos()

Description copied from class: AbstractClassifier

This method returns further information of a classifier as a StringBuffer. This method is used by the method AbstractClassifier.toXML() and should not be made public.

Overrides:

getFurtherClassifierInfos in class AbstractScoreBasedClassifier

Returns:

further information of a classifier as a StringBuffer

getScore

protected double getScore(Sequence seq,
                          int i,
                          boolean check)
                   throws IllegalArgumentException,
                          NotTrainedException,
                          Exception

Description copied from class: AbstractScoreBasedClassifier

This method returns the score for a given sequence and a given class.

Specified by:

getScore in class AbstractScoreBasedClassifier

Parameters:

seq - the sequence

i - the index of the class

check - the switch to decide whether to check AlphabetContainer and length of the sequence or not

Returns:

the score for a given sequence and a given class

Throws:

IllegalArgumentException - if something is wrong with seq

NotTrainedException - if the classifier is not trained

Exception - if something went wrong

getClassifierAnnotation

public CategoricalResult[] getClassifierAnnotation()

Description copied from class: AbstractClassifier

Returns an array of Results of dimension AbstractClassifier.getNumberOfClasses() that contains information about the classifier and for each class.
res[0] = new CategoricalResult( "classifier", "the kind of classifier", getInstanceName() );
res[1] = new CategoricalResult( "class info 0", "some information about the class", "info0" );
res[2] = new CategoricalResult( "class info 1", "some information about the class", "info1" );
...

Specified by:

getClassifierAnnotation in class AbstractClassifier

Returns:

an array of Results that contains information the classifier

getInstanceName

public String getInstanceName()

Description copied from class: AbstractClassifier

Returns a short description of the classifier.

Specified by:

getInstanceName in class AbstractClassifier

Returns:

a short description of the classifier

getNumericalCharacteristics

public NumericalResultSet getNumericalCharacteristics()
                                               throws Exception

Description copied from class: AbstractClassifier

Returns the subset of numerical values that are also returned by AbstractClassifier.getCharacteristics().

Specified by:

getNumericalCharacteristics in class AbstractClassifier

Returns:

the numerical characteristics

Throws:

Exception - an Exception is thrown if some of the characteristics could not be defined

getXMLTag

protected String getXMLTag()

Description copied from class: AbstractClassifier

Returns the String that is used as tag for the XML representation. This method is used by the methods AbstractClassifier.fromXML(StringBuffer) and AbstractClassifier.toXML().

Specified by:

getXMLTag in class AbstractClassifier

Returns:

the String that is used as tag for the XML representation

isTrained

public boolean isTrained()

Description copied from class: AbstractClassifier

This method gives information about the state of the classifier.

Specified by:

isTrained in class AbstractClassifier

Returns:

true if the classifier is able to classify sequences, otherwise false

train

public void train(Sample[] s,
                  double[][] weights)
           throws Exception

Description copied from class: AbstractClassifier

This method trains a classifier over an array of weighted Samples. That is why the following has to be fulfilled:

• s.length == weights.length
• and for all i: weights[i] == null || s[i].getNumberOfElements() == weights[i].length.

This method should work non-incrementally as the method train( Sample[] ).

This method should check that the Samples are defined over the underlying alphabet and length.

Specified by:

train in class AbstractClassifier

Parameters:

s - an array of Samples

weights - the weights for s

Throws:

Exception - an Exception should be thrown if the weights are incorrect or the training did not succeed

mapSample

public Sample[] mapSample(Sample[] s)

This method maps the samples to the internal classes.

Parameters:

s - the array of samples corresponding to the classes of the internal classifier

Returns:

the array of samples corresponding to the classes