java.lang.Object
- weka.attributeSelection.ASEvaluation
- - weka.attributeSelection.InfoGainAttributeEval

All Implemented Interfaces:

java.io.Serializable, AttributeEvaluator, CapabilitiesHandler, OptionHandler, RevisionHandler
```
public class InfoGainAttributeEval
extends ASEvaluation
implements AttributeEvaluator, OptionHandler
```
InfoGainAttributeEval :

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

InfoGain(Class,Attribute) = H(Class) - H(Class | Attribute).

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:

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

See Also:

Discretize, NumericToBinary, Serialized Form

Constructor Summary

Constructors
Constructor Description

InfoGainAttributeEval()
Constructor

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`java.lang.String`	`binarizeNumericAttributesTipText()`	Returns the tip text for this property
`void`	`buildEvaluator(Instances data)`	Initializes an information gain attribute evaluator.
`double`	`evaluateAttribute(int attribute)`	evaluates an individual attribute by measuring the amount of information gained about the class given the attribute.
`boolean`	`getBinarizeNumericAttributes()`	get whether numeric attributes are just being binarized.
`Capabilities`	`getCapabilities()`	Returns the capabilities of this evaluator.
`boolean`	`getMissingMerge()`	get whether missing values are being distributed or not
`java.lang.String[]`	`getOptions()`	Gets the current settings of WrapperSubsetEval.
`java.lang.String`	`getRevision()`	Returns the revision string.
`java.lang.String`	`globalInfo()`	Returns a string describing this attribute evaluator
`java.util.Enumeration`	`listOptions()`	Returns an enumeration describing the available options.
`static void`	`main(java.lang.String[] args)`	Main method for testing this class.
`java.lang.String`	`missingMergeTipText()`	Returns the tip text for this property
`void`	`setBinarizeNumericAttributes(boolean b)`	Binarize numeric attributes.
`void`	`setMissingMerge(boolean b)`	distribute the counts for missing values across observed values
`void`	`setOptions(java.lang.String[] options)`	Parses a given list of options.
`java.lang.String`	`toString()`	Describe the attribute evaluator

Methods inherited from class weka.attributeSelection.ASEvaluation
clean, forName, makeCopies, postProcess

Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Constructor Detail
  - InfoGainAttributeEval
```
public InfoGainAttributeEval()
```
    Constructor
- Method Detail
  - globalInfo
```
public java.lang.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 java.util.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(java.lang.String[] options)
                throws java.lang.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:
    
    java.lang.Exception - if an option is not supported
  - getOptions
```
public java.lang.String[] getOptions()
```
    Gets the current settings of WrapperSubsetEval.
    
    Specified by:
    
    getOptions in interface OptionHandler
    
    Returns:
    
    an array of strings suitable for passing to setOptions()
  - binarizeNumericAttributesTipText
```
public java.lang.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 java.lang.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:
    
    Capabilities
  - buildEvaluator
```
public void buildEvaluator(Instances data)
                    throws java.lang.Exception
```
    Initializes an information gain attribute evaluator. Discretizes all attributes that are numeric.
    
    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
  - evaluateAttribute
```
public double evaluateAttribute(int attribute)
                         throws java.lang.Exception
```
    evaluates an individual attribute by measuring the amount of information gained about the class given the attribute.
    
    Specified by:
    
    evaluateAttribute in interface AttributeEvaluator
    
    Parameters:
    
    attribute - the index of the attribute to be evaluated
    
    Returns:
    
    the info gain
    
    Throws:
    
    java.lang.Exception - if the attribute could not be evaluated
  - toString
```
public java.lang.String toString()
```
    Describe the attribute evaluator
    
    Overrides:
    
    toString in class java.lang.Object
    
    Returns:
    
    a description of the attribute 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
  - main
```
public static void main(java.lang.String[] args)
```
    Main method for testing this class.
    
    Parameters:
    
    args - the options

Class InfoGainAttributeEval

Constructor Summary

Method Summary

Methods inherited from class weka.attributeSelection.ASEvaluation

Methods inherited from class java.lang.Object

Constructor Detail

InfoGainAttributeEval

Method Detail

globalInfo

listOptions

setOptions

getOptions

binarizeNumericAttributesTipText

setBinarizeNumericAttributes

getBinarizeNumericAttributes

missingMergeTipText

setMissingMerge

getMissingMerge

getCapabilities

buildEvaluator

evaluateAttribute

toString

getRevision

main