Package weka.attributeSelection

Class GainRatioAttributeEval

java.lang.Object

weka.attributeSelection.ASEvaluation

weka.attributeSelection.GainRatioAttributeEval

All Implemented Interfaces:

Serializable, AttributeEvaluator, CapabilitiesHandler, CapabilitiesIgnorer, CommandlineRunnable, OptionHandler, RevisionHandler

public class GainRatioAttributeEval
extends ASEvaluation
implements AttributeEvaluator, OptionHandler

GainRatioAttributeEval :

Evaluates the worth of an attribute by measuring the gain ratio with respect to the class.

GainR(Class, Attribute) = (H(Class) - H(Class | Attribute)) / H(Attribute).

Valid options are:

 -M
  treat missing values as a separate value.
 

Version:

$Revision$

Author:

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

See Also:

Discretize, Serialized Form

Constructor Summary

Constructors

Constructor	Description
GainRatioAttributeEval()	Constructor

Method Summary

Modifier and Type	Method	Description
void	buildEvaluator(Instances data)	Initializes a gain ratio attribute evaluator.
double	evaluateAttribute(int attribute)	evaluates an individual attribute by measuring the gain ratio of the class given the attribute.
Capabilities	getCapabilities()	Returns the capabilities of this evaluator.
boolean	getMissingMerge()	get whether missing values are being distributed or not
String[]	getOptions()	Gets the current settings of WrapperSubsetEval.
String	getRevision()	Returns the revision string.
String	globalInfo()	Returns a string describing this attribute evaluator
Enumeration<Option>	listOptions()	Returns an enumeration describing the available options.
static void	main(String[] args)	Main method.
String	missingMergeTipText()	Returns the tip text for this property
int[]	postProcess(int[] attributeSet)	Provides a chance for a attribute evaluator to do any special post processing of the selected attribute set.
void	setMissingMerge(boolean b)	distribute the counts for missing values across observed values
void	setOptions(String[] options)	Parses a given list of options.
String	toString()	Return a description of the evaluator

Methods inherited from class weka.attributeSelection.ASEvaluation

clean, doNotCheckCapabilitiesTipText, forName, getDoNotCheckCapabilities, makeCopies, postExecution, preExecution, run, runEvaluator, setDoNotCheckCapabilities

Methods inherited from class java.lang.Object

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

Constructor Detail

GainRatioAttributeEval

public GainRatioAttributeEval()

Constructor

Method Detail

globalInfo

public String globalInfo()

Returns a string describing this attribute evaluator

Returns:

a description of the evaluator suitable for displaying in the explorer/experimenter gui

listOptions

public Enumeration<Option> listOptions()

Returns an enumeration describing the available options.

Specified by:

listOptions in interface OptionHandler

Overrides:

listOptions in class ASEvaluation

Returns:

an enumeration of all the available options.

setOptions

public void setOptions(String[] options)
                throws Exception

Parses a given list of options.

Valid options are:

 -M
  treat missing values as a separate value.
 

Specified by:

setOptions in interface OptionHandler

Overrides:

setOptions in class ASEvaluation

Parameters:

options - the list of options as an array of strings

Throws:

Exception - if an option is not supported

missingMergeTipText

public String missingMergeTipText()

Returns the tip text for this property

Returns:

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

setMissingMerge

public void setMissingMerge(boolean b)

distribute the counts for missing values across observed values

Parameters:

b - true=distribute missing values.

getMissingMerge

public boolean getMissingMerge()

get whether missing values are being distributed or not

Returns:

true if missing values are being distributed.

getOptions

public String[] getOptions()

Gets the current settings of WrapperSubsetEval.

Specified by:

getOptions in interface OptionHandler

Overrides:

getOptions in class ASEvaluation

Returns:

an array of strings suitable for passing to setOptions()

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 Exception

Initializes a gain ratio attribute evaluator. Discretizes all attributes that are numeric.

Specified by:

buildEvaluator in class ASEvaluation

Parameters:

data - set of instances serving as training data

Throws:

Exception - if the evaluator has not been generated successfully

evaluateAttribute

public double evaluateAttribute(int attribute)
                         throws Exception

evaluates an individual attribute by measuring the gain ratio of the class given the attribute.

Specified by:

evaluateAttribute in interface AttributeEvaluator

Parameters:

attribute - the index of the attribute to be evaluated

Returns:

the gain ratio

Throws:

Exception - if the attribute could not be evaluated

toString

public String toString()

Return a description of the evaluator

Overrides:

toString in class Object

Returns:

description as a string

getRevision

public String getRevision()

Returns the revision string.

Specified by:

getRevision in interface RevisionHandler

Overrides:

getRevision in class ASEvaluation

Returns:

the revision

postProcess

public int[] postProcess(int[] attributeSet)

Description copied from class: ASEvaluation

Provides a chance for a attribute evaluator to do any special post processing of the selected attribute set. Can also be used to clean up any data structures post attribute selection.

Overrides:

postProcess in class ASEvaluation

Parameters:

attributeSet - the set of attributes found by the search

Returns:

a possibly ranked list of postprocessed attributes

main

public static void main(String[] args)

Main method.

Parameters:

args - the options -t training file