weka.attributeSelection

Class ConsistencySubsetEval

java.lang.Object

weka.attributeSelection.ASEvaluation

weka.attributeSelection.ConsistencySubsetEval

All Implemented Interfaces:

java.io.Serializable, SubsetEvaluator, CapabilitiesHandler, RevisionHandler, TechnicalInformationHandler

public class ConsistencySubsetEval
extends ASEvaluation
implements SubsetEvaluator, TechnicalInformationHandler

ConsistencySubsetEval :

Evaluates the worth of a subset of attributes by the level of consistency in the class values when the training instances are projected onto the subset of attributes.

Consistency of any subset can never be lower than that of the full set of attributes, hence the usual practice is to use this subset evaluator in conjunction with a Random or Exhaustive search which looks for the smallest subset with consistency equal to that of the full set of attributes.

For more information see:

H. Liu, R. Setiono: A probabilistic approach to feature selection - A filter solution. In: 13th International Conference on Machine Learning, 319-327, 1996.

BibTeX:

 @inproceedings{Liu1996,
    author = {H. Liu and R. Setiono},
    booktitle = {13th International Conference on Machine Learning},
    pages = {319-327},
    title = {A probabilistic approach to feature selection - A filter solution},
    year = {1996}
 }
 

Version:

$Revision: 11851 $

Author:

Mark Hall (mhall@cs.waikato.ac.nz)

See Also:

Discretize, Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	ConsistencySubsetEval.hashKey Class providing keys to the hash table.

Constructor Summary

Constructors

Constructor and Description
ConsistencySubsetEval() Constructor.

Method Summary

Modifier and Type	Method and Description
void	buildEvaluator(Instances data) Generates a attribute evaluator.
void	clean() Tells the evaluator that the attribute selection process is complete.
double	evaluateSubset(java.util.BitSet subset) Evaluates a subset of attributes
Capabilities	getCapabilities() Returns the capabilities of this evaluator.
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 this search method
static void	main(java.lang.String[] args) Main method for testing this class.
java.lang.String	toString() returns a description of the evaluator

Methods inherited from class weka.attributeSelection.ASEvaluation

forName, makeCopies, postProcess

Methods inherited from class java.lang.Object

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

Constructor Detail

ConsistencySubsetEval

public ConsistencySubsetEval()

Constructor. Calls restOptions to set default options

Method Detail

globalInfo

public java.lang.String globalInfo()

Returns a string describing this search method

Returns:

a description of the search 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

getCapabilities

public Capabilities getCapabilities()

Returns the capabilities of this evaluator.

Specified by:

getCapabilities in interface CapabilitiesHandler

Overrides:

getCapabilities in class ASEvaluation

Returns:

the capabilities of this evaluator

See Also:

Capabilities

buildEvaluator

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

Generates a attribute evaluator. Has to initialize all fields of the evaluator that are not being set via options.

Specified by:

buildEvaluator in class ASEvaluation

Parameters:

data - set of instances serving as training data

Throws:

java.lang.Exception - if the evaluator has not been generated successfully

evaluateSubset

public double evaluateSubset(java.util.BitSet subset)
                      throws java.lang.Exception

Evaluates a subset of attributes

Specified by:

evaluateSubset in interface SubsetEvaluator

Parameters:

subset - a bitset representing the attribute subset to be evaluated

Returns:

the "merit" of the subset

Throws:

java.lang.Exception - if the subset could not be evaluated

toString

public java.lang.String toString()

returns a description of the evaluator

Overrides:

toString in class java.lang.Object

Returns:

a description of the evaluator as a String.

getRevision

public java.lang.String getRevision()

Returns the revision string.

Specified by:

getRevision in interface RevisionHandler

Overrides:

getRevision in class ASEvaluation

Returns:

the revision

clean

public void clean()

Description copied from class: ASEvaluation

Tells the evaluator that the attribute selection process is complete. It can then clean up data structures, references to training data as necessary in order to save memory

Overrides:

clean in class ASEvaluation

main

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

Main method for testing this class.

Parameters:

args - the options