weka.attributeSelection

Class CorrelationAttributeEval

java.lang.Object

weka.attributeSelection.ASEvaluation

weka.attributeSelection.CorrelationAttributeEval

All Implemented Interfaces:

Serializable, AttributeEvaluator, CapabilitiesHandler, OptionHandler, RevisionHandler

public class CorrelationAttributeEval
extends ASEvaluation
implements AttributeEvaluator, OptionHandler

CorrelationAttributeEval :

Evaluates the worth of an attribute by measuring the correlation (Pearson's) between it and the class.

Nominal attributes are considered on a value by value basis by treating each value as an indicator. An overall correlation for a nominal attribute is arrived at via a weighted average.

Valid options are:

 -D
  Output detailed info for nominal attributes
 

Version:

$Revision: 10172 $

Author:

Mark Hall (mhall{[at]}pentaho{[dot]}com)

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
CorrelationAttributeEval()

Method Summary

Methods

Modifier and Type	Method and Description
void	buildEvaluator(Instances data) Initializes an information gain attribute evaluator.
double	evaluateAttribute(int attribute) Evaluates an individual attribute by measuring the correlation (Pearson's) between it and the class.
Capabilities	getCapabilities() Returns the capabilities of this evaluator.
String[]	getOptions() Gets the current settings of WrapperSubsetEval.
boolean	getOutputDetailedInfo() Get whether to output per-value correlation for nominal attributes
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 for testing this class.
String	outputDetailedInfoTipText() Returns the tip text for this property
void	setOptions(String[] options) Parses a given list of options.
void	setOutputDetailedInfo(boolean d) Set whether to output per-value correlation for nominal attributes
String	toString() Describe the attribute evaluator

Methods inherited from class weka.attributeSelection.ASEvaluation

forName, makeCopies, postProcess, runEvaluator

Methods inherited from class java.lang.Object

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

Constructor Detail

CorrelationAttributeEval

public CorrelationAttributeEval()

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

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

listOptions

public Enumeration<Option> listOptions()

Returns an enumeration describing the available options.

Specified by:

listOptions in interface OptionHandler

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:

 -D
  Output detailed info for nominal attributes
 

Specified by:

setOptions in interface OptionHandler

Parameters:

options - the list of options as an array of strings

Throws:

Exception - if an option is not supported

getOptions

public String[] getOptions()

Gets the current settings of WrapperSubsetEval.

Specified by:

getOptions in interface OptionHandler

Returns:

an array of strings suitable for passing to setOptions()

outputDetailedInfoTipText

public String outputDetailedInfoTipText()

Returns the tip text for this property

Returns:

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

setOutputDetailedInfo

public void setOutputDetailedInfo(boolean d)

Set whether to output per-value correlation for nominal attributes

Parameters:

d - true if detailed (per-value) correlation is to be output for nominal attributes

getOutputDetailedInfo

public boolean getOutputDetailedInfo()

Get whether to output per-value correlation for nominal attributes

Returns:

true if detailed (per-value) correlation is to be output for nominal attributes

evaluateAttribute

public double evaluateAttribute(int attribute)
                         throws Exception

Evaluates an individual attribute by measuring the correlation (Pearson's) between it and the class. Nominal attributes are considered on a value by value basis by treating each value as an indicator. An overall correlation for a nominal attribute is arrived at via a weighted average.

Specified by:

evaluateAttribute in interface AttributeEvaluator

Parameters:

attribute - the index of the attribute to be evaluated

Returns:

the correlation

Throws:

Exception - if the attribute could not be evaluated

toString

public String toString()

Describe the attribute evaluator

Overrides:

toString in class Object

Returns:

a description of the attribute evaluator as a String

buildEvaluator

public void buildEvaluator(Instances data)
                    throws Exception

Initializes an information gain attribute evaluator. Replaces missing values with means/modes; Deletes instances with missing class values.

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

getRevision

public String getRevision()

Returns the revision string.

Specified by:

getRevision in interface RevisionHandler

Overrides:

getRevision in class ASEvaluation

Returns:

the revision

main

public static void main(String[] args)

Main method for testing this class.

Parameters:

args - the options