Class 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 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
      • 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.
      • 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