Package weka.attributeSelection

Class RandomSearch

  • All Implemented Interfaces:
    java.io.Serializable, StartSetHandler, OptionHandler, RevisionHandler, TechnicalInformationHandler
    public class RandomSearch
extends ASSearch
implements StartSetHandler, OptionHandler, TechnicalInformationHandler
    RandomSearch :

    Performs a Random search in the space of attribute subsets. If no start set is supplied, Random search starts from a random point and reports the best subset found. If a start set is supplied, Random searches randomly for subsets that are as good or better than the start point with the same or or fewer attributes. Using RandomSearch in conjunction with a start set containing all attributes equates to the LVF algorithm of Liu and Setiono (ICML-96).

    For more information see:

    H. Liu, R. Setiono: A probabilistic approach to feature selection - A filter solution. In: 13th International Conference on Machine Learning, 319-327, 1996.

    BibTeX: 

     @inproceedings{Liu1996,
    author = {H. Liu and R. Setiono},
    booktitle = {13th International Conference on Machine Learning},
    pages = {319-327},
    title = {A probabilistic approach to feature selection - A filter solution},
    year = {1996}
 }

    Valid options are: 

     -P <start set>
  Specify a starting set of attributes.
  Eg. 1,3,5-7.
  If a start point is supplied,
  random search evaluates the start
  point and then randomly looks for
  subsets that are as good as or better
  than the start point with the same
  or lower cardinality.
     -F <percent> 
  Percent of search space to consider.
  (default = 25%).
     -V
  Output subsets as the search progresses.
  (default = false).
     -seed <num>
  Random seed
  (default = 1)
    Version:
    $Revision: 8949 $
    Author:
    Mark Hall (mhall@cs.waikato.ac.nz)
    See Also:
    Serialized Form

    • Constructor Summary

      Constructors 
      Constructor Description
      RandomSearch()
      Constructor

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      java.lang.String[] getOptions()
      Gets the current settings of RandomSearch.
      java.lang.String getRevision()
      Returns the revision string.
      double getSearchPercent()
      get the percentage of the search space to consider
      int getSeed()
      Get the random seed to use
      java.lang.String getStartSet()
      Returns a list of attributes (and or attribute ranges) as a String
      TechnicalInformation getTechnicalInformation()
      Returns an instance of a TechnicalInformation object, containing detailed information about the technical background of this class, e.g., paper reference or book this class is based on.
      boolean getVerbose()
      get whether or not output is verbose
      java.lang.String globalInfo()
      Returns a string describing this search method
      java.util.Enumeration listOptions()
      Returns an enumeration describing the available options.
      int[] search​(ASEvaluation ASEval, Instances data)
      Searches the attribute subset space randomly.
      java.lang.String searchPercentTipText()
      Returns the tip text for this property
      java.lang.String seedTipText()
      Returns the tip text for this property
      void setOptions​(java.lang.String[] options)
      Parses a given list of options.
      void setSearchPercent​(double p)
      set the percentage of the search space to consider
      void setSeed​(int seed)
      Set the random seed to use
      void setStartSet​(java.lang.String startSet)
      Sets a starting set of attributes for the search.
      void setVerbose​(boolean v)
      set whether or not to output new best subsets as the search proceeds
      java.lang.String startSetTipText()
      Returns the tip text for this property
      java.lang.String toString()
      prints a description of the search
      java.lang.String verboseTipText()
      Returns the tip text for this property

      • Methods inherited from class java.lang.Object

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

    • Constructor Detail

      • RandomSearch

        public RandomSearch()
        Constructor

    • Method Detail

      • globalInfo

        public java.lang.String globalInfo()
        Returns a string describing this search method
        Returns:
        a description of the search suitable for displaying in the explorer/experimenter gui

      • getTechnicalInformation

        public TechnicalInformation getTechnicalInformation()
        Returns an instance of a TechnicalInformation object, containing detailed information about the technical background of this class, e.g., paper reference or book this class is based on.
        Specified by:
        getTechnicalInformation in interface TechnicalInformationHandler
        Returns:
        the technical information about this class

      • 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: 

         -P <start set>
  Specify a starting set of attributes.
  Eg. 1,3,5-7.
  If a start point is supplied,
  random search evaluates the start
  point and then randomly looks for
  subsets that are as good as or better
  than the start point with the same
  or lower cardinality.
         -F <percent> 
  Percent of search space to consider.
  (default = 25%).
         -V
  Output subsets as the search progresses.
  (default = false).
         -seed <num>
  Random seed
  (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 of RandomSearch.
        Specified by:
        getOptions in interface OptionHandler
        Returns:
        an array of strings suitable for passing to setOptions()

      • startSetTipText

        public java.lang.String startSetTipText()
        Returns the tip text for this property
        Returns:
        tip text for this property suitable for displaying in the explorer/experimenter gui

      • setStartSet

        public void setStartSet​(java.lang.String startSet)
                 throws java.lang.Exception
        Sets a starting set of attributes for the search. It is the search method's responsibility to report this start set (if any) in its toString() method.
        Specified by:
        setStartSet in interface StartSetHandler
        Parameters:
        startSet - a string containing a list of attributes (and or ranges), eg. 1,2,6,10-15. "" indicates no start point. If a start point is supplied, random search evaluates the start point and then looks for subsets that are as good as or better than the start point with the same or lower cardinality.
        Throws:
        java.lang.Exception - if start set can't be set.

      • getStartSet

        public java.lang.String getStartSet()
        Returns a list of attributes (and or attribute ranges) as a String
        Specified by:
        getStartSet in interface StartSetHandler
        Returns:
        a list of attributes (and or attribute ranges)

      • verboseTipText

        public java.lang.String verboseTipText()
        Returns the tip text for this property
        Returns:
        tip text for this property suitable for displaying in the explorer/experimenter gui

      • setVerbose

        public void setVerbose​(boolean v)
        set whether or not to output new best subsets as the search proceeds
        Parameters:
        v - true if output is to be verbose

      • getVerbose

        public boolean getVerbose()
        get whether or not output is verbose
        Returns:
        true if output is set to verbose

      • searchPercentTipText

        public java.lang.String searchPercentTipText()
        Returns the tip text for this property
        Returns:
        tip text for this property suitable for displaying in the explorer/experimenter gui

      • setSearchPercent

        public void setSearchPercent​(double p)
        set the percentage of the search space to consider
        Parameters:
        p - percent of the search space ( 0 < p <= 100)

      • seedTipText

        public java.lang.String seedTipText()
        Returns the tip text for this property
        Returns:
        tip text for this property suitable for displaying in the explorer/experimenter gui

      • setSeed

        public void setSeed​(int seed)
        Set the random seed to use
        Parameters:
        seed - the seed to use

      • getSeed

        public int getSeed()
        Get the random seed to use
        Returns:
        the random seed

      • getSearchPercent

        public double getSearchPercent()
        get the percentage of the search space to consider
        Returns:
        the percent of the search space explored

      • toString

        public java.lang.String toString()
        prints a description of the search
        Overrides:
        toString in class java.lang.Object
        Returns:
        a description of the search as a string

      • search

        public int[] search​(ASEvaluation ASEval,
                    Instances data)
             throws java.lang.Exception
        Searches the attribute subset space randomly.
        Specified by:
        search in class ASSearch
        Parameters:
        ASEval - the attribute evaluator to guide the search
        data - the training instances.
        Returns:
        an array (not necessarily ordered) of selected attribute indexes
        Throws:
        java.lang.Exception - if the search can't be completed