weka.classifiers.meta

Class Stacking

java.lang.Object

weka.classifiers.AbstractClassifier

weka.classifiers.MultipleClassifiersCombiner

weka.classifiers.ParallelMultipleClassifiersCombiner

weka.classifiers.RandomizableParallelMultipleClassifiersCombiner

weka.classifiers.meta.Stacking

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable, Classifier, BatchPredictor, CapabilitiesHandler, CapabilitiesIgnorer, CommandlineRunnable, OptionHandler, Randomizable, RevisionHandler, TechnicalInformationHandler

public class Stacking
extends RandomizableParallelMultipleClassifiersCombiner
implements TechnicalInformationHandler

Combines several classifiers using the stacking method. Can do classification or regression.

For more information, see

David H. Wolpert (1992). Stacked generalization. Neural Networks. 5:241-259.

BibTeX:

 @article{Wolpert1992,
    author = {David H. Wolpert},
    journal = {Neural Networks},
    pages = {241-259},
    publisher = {Pergamon Press},
    title = {Stacked generalization},
    volume = {5},
    year = {1992}
 }
 

Valid options are:

 -M <scheme specification>
  Full name of meta classifier, followed by options.
  (default: "weka.classifiers.rules.Zero")

 -X <number of folds>
  Sets the number of cross-validation folds.

 -S <num>
  Random number seed.
  (default 1)

 -B <classifier specification>
  Full class name of classifier to include, followed
  by scheme options. May be specified multiple times.
  (default: "weka.classifiers.rules.ZeroR")

 -D
  If set, classifier is run in debug mode and
  may output additional info to the console

Version:

$Revision: 15032 $

Author:

Eibe Frank (eibe@cs.waikato.ac.nz)

See Also:

Serialized Form

Field Summary

Fields inherited from class weka.classifiers.AbstractClassifier

BATCH_SIZE_DEFAULT, NUM_DECIMAL_PLACES_DEFAULT

Constructor Summary

Constructors

Constructor and Description
Stacking()

Method Summary

Modifier and Type	Method and Description
boolean	baseClassifiersImplementMoreEfficientBatchPrediction() Returns true if any of the base classifiers are able to generate batch predictions efficiently and all of them implement BatchPredictor.
void	buildClassifier(Instances data) Builds a classifier using stacking.
double[]	distributionForInstance(Instance instance) Returns estimated class probabilities for the given instance if the class is nominal and a one-element array containing the numeric prediction if the class is numeric.
double[][]	distributionsForInstances(Instances instances) Returns class probabilities for all given instances if the class is nominal or corresponding predicted numeric values if the class is numeric.
Capabilities	getCapabilities() Returns combined capabilities of the base classifiers, i.e., the capabilities all of them have in common.
Classifier	getMetaClassifier() Gets the meta classifier.
int	getNumFolds() Gets the number of folds for the cross-validation.
java.lang.String[]	getOptions() Gets the current settings of the Classifier.
java.lang.String	getRevision() Returns the revision string.
TechnicalInformation	getTechnicalInformation() Returns an instance of a TechnicalInformation object, containing detailed information about the technical background of this class, e.g., paper reference or book this class is based on.
java.lang.String	globalInfo() Returns a string describing classifier
boolean	implementsMoreEfficientBatchPrediction() Returns true if the meta classifier or any of the base classifiers are able to generate batch predictions efficiently and all of them implement BatchPredictor.
java.util.Enumeration<Option>	listOptions() Returns an enumeration describing the available options.
static void	main(java.lang.String[] argv) Main method for testing this class.
java.lang.String	metaClassifierTipText() Returns the tip text for this property
java.lang.String	numFoldsTipText() Returns the tip text for this property
void	postExecution() Perform any teardown stuff that might need to happen after execution.
void	preExecution() Perform any setup stuff that might need to happen before commandline execution.
void	setMetaClassifier(Classifier classifier) Adds meta classifier
void	setNumFolds(int numFolds) Sets the number of folds for the cross-validation.
void	setOptions(java.lang.String[] options) Parses a given list of options.
java.lang.String	toString() Output a representation of this classifier

Methods inherited from class weka.classifiers.RandomizableParallelMultipleClassifiersCombiner

getSeed, seedTipText, setSeed

Methods inherited from class weka.classifiers.ParallelMultipleClassifiersCombiner

getNumExecutionSlots, numExecutionSlotsTipText, setNumExecutionSlots

Methods inherited from class weka.classifiers.MultipleClassifiersCombiner

classifiersTipText, getClassifier, getClassifiers, setClassifiers

Methods inherited from class weka.classifiers.AbstractClassifier

batchSizeTipText, classifyInstance, debugTipText, doNotCheckCapabilitiesTipText, forName, getBatchSize, getDebug, getDoNotCheckCapabilities, getNumDecimalPlaces, makeCopies, makeCopy, numDecimalPlacesTipText, run, runClassifier, setBatchSize, setDebug, setDoNotCheckCapabilities, setNumDecimalPlaces

Methods inherited from class java.lang.Object

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

Methods inherited from interface weka.core.OptionHandler

makeCopy

Constructor Detail

Stacking

public Stacking()

Method Detail

globalInfo

public java.lang.String globalInfo()

Returns a string describing classifier

Returns:

a description suitable for displaying in the explorer/experimenter gui

getTechnicalInformation

public TechnicalInformation getTechnicalInformation()

Returns an instance of a TechnicalInformation object, containing detailed information about the technical background of this class, e.g., paper reference or book this class is based on.

Specified by:

getTechnicalInformation in interface TechnicalInformationHandler

Returns:

the technical information about this class

listOptions

public java.util.Enumeration<Option> listOptions()

Returns an enumeration describing the available options.

Specified by:

listOptions in interface OptionHandler

Overrides:

listOptions in class RandomizableParallelMultipleClassifiersCombiner

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:

 -M <scheme specification>
  Full name of meta classifier, followed by options.
  (default: "weka.classifiers.rules.Zero")

 -X <number of folds>
  Sets the number of cross-validation folds.

 -S <num>
  Random number seed.
  (default 1)

 -B <classifier specification>
  Full class name of classifier to include, followed
  by scheme options. May be specified multiple times.
  (default: "weka.classifiers.rules.ZeroR")

 -D
  If set, classifier is run in debug mode and
  may output additional info to the console

Specified by:

setOptions in interface OptionHandler

Overrides:

setOptions in class RandomizableParallelMultipleClassifiersCombiner

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 Classifier.

Specified by:

getOptions in interface OptionHandler

Overrides:

getOptions in class RandomizableParallelMultipleClassifiersCombiner

Returns:

an array of strings suitable for passing to setOptions

numFoldsTipText

public java.lang.String numFoldsTipText()

Returns the tip text for this property

Returns:

tip text for this property suitable for displaying in the explorer/experimenter gui

getNumFolds

public int getNumFolds()

Gets the number of folds for the cross-validation.

Returns:

the number of folds for the cross-validation

setNumFolds

public void setNumFolds(int numFolds)
                 throws java.lang.Exception

Sets the number of folds for the cross-validation.

Parameters:

numFolds - the number of folds for the cross-validation

Throws:

java.lang.Exception - if parameter illegal

metaClassifierTipText

public java.lang.String metaClassifierTipText()

Returns the tip text for this property

Returns:

tip text for this property suitable for displaying in the explorer/experimenter gui

setMetaClassifier

public void setMetaClassifier(Classifier classifier)

Adds meta classifier

Parameters:

classifier - the classifier with all options set.

getMetaClassifier

public Classifier getMetaClassifier()

Gets the meta classifier.

Returns:

the meta classifier

getCapabilities

public Capabilities getCapabilities()

Returns combined capabilities of the base classifiers, i.e., the capabilities all of them have in common.

Specified by:

getCapabilities in interface Classifier

Specified by:

getCapabilities in interface CapabilitiesHandler

Overrides:

getCapabilities in class MultipleClassifiersCombiner

Returns:

the capabilities of the base classifiers

See Also:

Capabilities

implementsMoreEfficientBatchPrediction

public boolean implementsMoreEfficientBatchPrediction()

Returns true if the meta classifier or any of the base classifiers are able to generate batch predictions efficiently and all of them implement BatchPredictor.

Specified by:

implementsMoreEfficientBatchPrediction in interface BatchPredictor

Overrides:

implementsMoreEfficientBatchPrediction in class AbstractClassifier

Returns:

true if batch prediction can be done efficiently

baseClassifiersImplementMoreEfficientBatchPrediction

public boolean baseClassifiersImplementMoreEfficientBatchPrediction()

Returns true if any of the base classifiers are able to generate batch predictions efficiently and all of them implement BatchPredictor.

Returns:

true if the base classifiers can do batch prediction efficiently

buildClassifier

public void buildClassifier(Instances data)
                     throws java.lang.Exception

Builds a classifier using stacking. The base classifiers' output is fed into the meta classifier to make the final decision. The training data for the meta classifier is generated using (stratified) cross-validation.

Specified by:

buildClassifier in interface Classifier

Overrides:

buildClassifier in class ParallelMultipleClassifiersCombiner

Parameters:

data - the training data to be used for generating the stacked classifier.

Throws:

java.lang.Exception - if the classifier could not be built successfully

distributionForInstance

public double[] distributionForInstance(Instance instance)
                                 throws java.lang.Exception

Returns estimated class probabilities for the given instance if the class is nominal and a one-element array containing the numeric prediction if the class is numeric.

Specified by:

distributionForInstance in interface Classifier

Overrides:

distributionForInstance in class AbstractClassifier

Parameters:

instance - the instance to be classified

Returns:

the distribution

Throws:

java.lang.Exception - if instance could not be classified successfully

distributionsForInstances

public double[][] distributionsForInstances(Instances instances)
                                     throws java.lang.Exception

Returns class probabilities for all given instances if the class is nominal or corresponding predicted numeric values if the class is numeric. The meta classifier must implement BatchPredictor, otherwise an exception will be thrown.

Specified by:

distributionsForInstances in interface BatchPredictor

Overrides:

distributionsForInstances in class AbstractClassifier

Parameters:

instances - the instance sto be classified

Returns:

the distributions

Throws:

java.lang.Exception - if instances could not be classified successfully

toString

public java.lang.String toString()

Output a representation of this classifier

Overrides:

toString in class java.lang.Object

Returns:

a string representation of the classifier

preExecution

public void preExecution()
                  throws java.lang.Exception

Description copied from class: AbstractClassifier

Perform any setup stuff that might need to happen before commandline execution. Subclasses should override if they need to do something here

Specified by:

preExecution in interface CommandlineRunnable

Overrides:

preExecution in class MultipleClassifiersCombiner

Throws:

java.lang.Exception - if a problem occurs during setup

postExecution

public void postExecution()
                   throws java.lang.Exception

Description copied from class: AbstractClassifier

Perform any teardown stuff that might need to happen after execution. Subclasses should override if they need to do something here

Specified by:

postExecution in interface CommandlineRunnable

Overrides:

postExecution in class MultipleClassifiersCombiner

Throws:

java.lang.Exception - if a problem occurs during teardown

getRevision

public java.lang.String getRevision()

Returns the revision string.

Specified by:

getRevision in interface RevisionHandler

Overrides:

getRevision in class AbstractClassifier

Returns:

the revision

main

public static void main(java.lang.String[] argv)

Main method for testing this class.

Parameters:

argv - should contain the following arguments: -t training file [-T test file] [-c class index]