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Class weka.attributeSelection.InfoGainAttributeEval 

java.lang.Object
   |
   +----weka.attributeSelection.ASEvaluation
           |
           +----weka.attributeSelection.AttributeEvaluator
                   |
                   +----weka.attributeSelection.InfoGainAttributeEval
public class InfoGainAttributeEval
extends AttributeEvaluator
implements OptionHandler
Class for Evaluating attributes individually by measuring information gain with respect to the class. Valid options are:

-M
Treat missing values as a seperate value.

Version:
$Revision: 1.5 $
Author:
Mark Hall (mhall@cs.waikato.ac.nz)

Constructor Index

o InfoGainAttributeEval()
Constructor

Method Index

o buildEvaluator(Instances)
Initializes an information gain attribute evaluator.
o evaluateAttribute(int)
evaluates an individual attribute by measuring the amount of information gained about the class given the attribute.
o getMissingMerge()
get whether missing values are being distributed or not
o getOptions()
Gets the current settings of WrapperSubsetEval.
o listOptions()
Returns an enumeration describing the available options
o main(String[])
Main method for testing this class.
o setMissingMerge(boolean)
distribute the counts for missing values across observed values
o setOptions(String[])
Parses a given list of options.
o toString()
Describe the attribute evaluator

Constructors

o InfoGainAttributeEval 
 public InfoGainAttributeEval()
Constructor

Methods

o listOptions 
 public Enumeration listOptions()
Returns an enumeration describing the available options

Returns:
an enumeration of all the available options
o 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.

Parameters:
options - the list of options as an array of strings
Throws: Exception
if an option is not supported
o getOptions 
 public String[] getOptions()
Gets the current settings of WrapperSubsetEval.

Returns:
an array of strings suitable for passing to setOptions()
o setMissingMerge 
 public void setMissingMerge(boolean b)
distribute the counts for missing values across observed values

Parameters:
b - true=distribute missing values.
o getMissingMerge 
 public boolean getMissingMerge()
get whether missing values are being distributed or not

Returns:
true if missing values are being distributed.
o buildEvaluator 
 public void buildEvaluator(Instances data) throws Exception
Initializes an information gain attribute evaluator. Discretizes all attributes that are numeric.

Parameters:
data - set of instances serving as training data
Throws: Exception
if the evaluator has not been generated successfully
Overrides:
buildEvaluator in class ASEvaluation
o evaluateAttribute 
 public double evaluateAttribute(int attribute) throws Exception
evaluates an individual attribute by measuring the amount of information gained about the class given the attribute.

Parameters:
attribute - the index of the attribute to be evaluated
Throws: Exception
if the attribute could not be evaluated
Overrides:
evaluateAttribute in class AttributeEvaluator
o toString 
 public String toString()
Describe the attribute evaluator

Returns:
a description of the attribute evaluator as a string
Overrides:
toString in class Object
o main 
 public static void main(String args[])
Main method for testing this class.

Parameters:
argv - the options 
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