weka.filters.supervised.attribute

Class AttributeSelection

java.lang.Object

weka.filters.Filter

weka.filters.supervised.attribute.AttributeSelection

All Implemented Interfaces:

java.io.Serializable, CapabilitiesHandler, OptionHandler, RevisionHandler, SupervisedFilter

public class AttributeSelection
extends Filter
implements SupervisedFilter, OptionHandler

A supervised attribute filter that can be used to select attributes. It is very flexible and allows various search and evaluation methods to be combined.

Valid options are:

 -S <"Name of search class [search options]">
  Sets search method for subset evaluators.
  eg. -S "weka.attributeSelection.BestFirst -S 8"

 -E <"Name of attribute/subset evaluation class [evaluator options]">
  Sets attribute/subset evaluator.
  eg. -E "weka.attributeSelection.CfsSubsetEval -L"

 
 Options specific to evaluator weka.attributeSelection.CfsSubsetEval:
 

 -M
  Treat missing values as a seperate value.

 -L
  Don't include locally predictive attributes.

 
 Options specific to search weka.attributeSelection.BestFirst:
 

 -P <start set>
  Specify a starting set of attributes.
  Eg. 1,3,5-7.

 -D <0 = backward | 1 = forward | 2 = bi-directional>
  Direction of search. (default = 1).

 -N <num>
  Number of non-improving nodes to
  consider before terminating search.

 -S <num>
  Size of lookup cache for evaluated subsets.
  Expressed as a multiple of the number of
  attributes in the data set. (default = 1)

Version:

$Revision: 10868 $

Author:

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

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
AttributeSelection() Constructor

Method Summary

Modifier and Type	Method and Description
boolean	batchFinished() Signify that this batch of input to the filter is finished.
java.lang.String	evaluatorTipText() Returns the tip text for this property
Capabilities	getCapabilities() Returns the Capabilities of this filter.
ASEvaluation	getEvaluator() Get the name of the attribute/subset evaluator
java.lang.String[]	getOptions() Gets the current settings for the attribute selection (search, evaluator) etc.
java.lang.String	getRevision() Returns the revision string.
ASSearch	getSearch() Get the name of the search method
java.lang.String	globalInfo() Returns a string describing this filter
boolean	input(Instance instance) Input an instance for filtering.
java.util.Enumeration	listOptions() Returns an enumeration describing the available options.
static void	main(java.lang.String[] argv) Main method for testing this class.
java.lang.String	searchTipText() Returns the tip text for this property
void	setEvaluator(ASEvaluation evaluator) set attribute/subset evaluator
void	setOptions(java.lang.String[] options) Parses a given list of options.
void	setSearch(ASSearch search) Set search class

Methods inherited from class weka.filters.Filter

batchFilterFile, filterFile, getCapabilities, getOutputFormat, isFirstBatchDone, isNewBatch, isOutputFormatDefined, makeCopies, makeCopy, numPendingOutput, output, outputPeek, setInputFormat, toString, useFilter, wekaStaticWrapper

Methods inherited from class java.lang.Object

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

Constructor Detail

AttributeSelection

public AttributeSelection()

Constructor

Method Detail

globalInfo

public java.lang.String globalInfo()

Returns a string describing this filter

Returns:

a description of the filter 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:

 -S <"Name of search class [search options]">
  Sets search method for subset evaluators.
  eg. -S "weka.attributeSelection.BestFirst -S 8"

 -E <"Name of attribute/subset evaluation class [evaluator options]">
  Sets attribute/subset evaluator.
  eg. -E "weka.attributeSelection.CfsSubsetEval -L"

 
 Options specific to evaluator weka.attributeSelection.CfsSubsetEval:
 

 -M
  Treat missing values as a seperate value.

 -L
  Don't include locally predictive attributes.

 
 Options specific to search weka.attributeSelection.BestFirst:
 

 -P <start set>
  Specify a starting set of attributes.
  Eg. 1,3,5-7.

 -D <0 = backward | 1 = forward | 2 = bi-directional>
  Direction of search. (default = 1).

 -N <num>
  Number of non-improving nodes to
  consider before terminating search.

 -S <num>
  Size of lookup cache for evaluated subsets.
  Expressed as a multiple of the number of
  attributes in the data set. (default = 1)

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 for the attribute selection (search, evaluator) etc.

Specified by:

getOptions in interface OptionHandler

Returns:

an array of strings suitable for passing to setOptions()

evaluatorTipText

public java.lang.String evaluatorTipText()

Returns the tip text for this property

Returns:

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

setEvaluator

public void setEvaluator(ASEvaluation evaluator)

set attribute/subset evaluator

Parameters:

evaluator - the evaluator to use

searchTipText

public java.lang.String searchTipText()

Returns the tip text for this property

Returns:

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

setSearch

public void setSearch(ASSearch search)

Set search class

Parameters:

search - the search class to use

getEvaluator

public ASEvaluation getEvaluator()

Get the name of the attribute/subset evaluator

Returns:

the name of the attribute/subset evaluator as a string

getSearch

public ASSearch getSearch()

Get the name of the search method

Returns:

the name of the search method as a string

getCapabilities

public Capabilities getCapabilities()

Returns the Capabilities of this filter.

Specified by:

getCapabilities in interface CapabilitiesHandler

Overrides:

getCapabilities in class Filter

Returns:

the capabilities of this object

See Also:

Capabilities

input

public boolean input(Instance instance)
              throws java.lang.Exception

Input an instance for filtering. Ordinarily the instance is processed and made available for output immediately. Some filters require all instances be read before producing output.

Overrides:

input in class Filter

Parameters:

instance - the input instance

Returns:

true if the filtered instance may now be collected with output().

Throws:

java.lang.IllegalStateException - if no input format has been defined.

java.lang.Exception - if the input instance was not of the correct format or if there was a problem with the filtering.

batchFinished

public boolean batchFinished()
                      throws java.lang.Exception

Signify that this batch of input to the filter is finished. If the filter requires all instances prior to filtering, output() may now be called to retrieve the filtered instances.

Overrides:

batchFinished in class Filter

Returns:

true if there are instances pending output.

Throws:

java.lang.IllegalStateException - if no input structure has been defined.

java.lang.Exception - if there is a problem during the attribute selection.

getRevision

public java.lang.String getRevision()

Returns the revision string.

Specified by:

getRevision in interface RevisionHandler

Overrides:

getRevision in class Filter

Returns:

the revision

main

public static void main(java.lang.String[] argv)

Main method for testing this class.

Parameters:

argv - should contain arguments to the filter: use -h for help