Class ChiSquaredAttributeEval

java.lang.Object
weka.attributeSelection.ASEvaluation
weka.attributeSelection.ChiSquaredAttributeEval
All Implemented Interfaces:
Serializable, AttributeEvaluator, CapabilitiesHandler, OptionHandler, RevisionHandler

public class ChiSquaredAttributeEval extends ASEvaluation implements AttributeEvaluator, OptionHandler
ChiSquaredAttributeEval :

Evaluates the worth of an attribute by computing the value of the chi-squared statistic with respect to the class.

Valid options are:

 -M
  treat missing values as a seperate value.
 -B
  just binarize numeric attributes instead 
  of properly discretizing them.
Version:
$Revision: 5511 $
Author:
Eibe Frank (eibe@cs.waikato.ac.nz)
See Also:
  • Constructor Details

    • ChiSquaredAttributeEval

      public ChiSquaredAttributeEval()
      Constructor
  • Method Details

    • 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 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:

       -M
        treat missing values as a seperate value.
       -B
        just binarize numeric attributes instead 
        of properly discretizing them.
      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.
      Specified by:
      getOptions in interface OptionHandler
      Returns:
      an array of strings suitable for passing to setOptions()
    • binarizeNumericAttributesTipText

      public String binarizeNumericAttributesTipText()
      Returns the tip text for this property
      Returns:
      tip text for this property suitable for displaying in the explorer/experimenter gui
    • setBinarizeNumericAttributes

      public void setBinarizeNumericAttributes(boolean b)
      Binarize numeric attributes.
      Parameters:
      b - true=binarize numeric attributes
    • getBinarizeNumericAttributes

      public boolean getBinarizeNumericAttributes()
      get whether numeric attributes are just being binarized.
      Returns:
      true if missing values are being distributed.
    • 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.
    • 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:
    • buildEvaluator

      public void buildEvaluator(Instances data) throws Exception
      Initializes a chi-squared 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 its chi-squared value.
      Specified by:
      evaluateAttribute in interface AttributeEvaluator
      Parameters:
      attribute - the index of the attribute to be evaluated
      Returns:
      the chi-squared value
      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
    • 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.
      Parameters:
      args - the options