Package weka.core.neighboursearch.balltrees

Class MedianOfWidestDimension

  • All Implemented Interfaces:
    java.io.Serializable, OptionHandler, RevisionHandler, TechnicalInformationHandler
    public class MedianOfWidestDimension
extends BallSplitter
implements OptionHandler, TechnicalInformationHandler
    Class that splits a BallNode of a ball tree based on the median value of the widest dimension of the points in the ball. It essentially implements Omohundro's KD construction algorithm.

    BibTeX: 

     @techreport{Omohundro1989,
    author = {Stephen M. Omohundro},
    institution = {International Computer Science Institute},
    month = {December},
    number = {TR-89-063},
    title = {Five Balltree Construction Algorithms},
    year = {1989}
 }

    Valid options are: 

     -N
  Normalize dimensions' widths.
    Version:
    $Revision: 1.2 $
    Author:
    Ashraf M. Kibriya (amk14[at-the-rate]cs[dot]waikato[dot]ac[dot]nz)
    See Also:
    Serialized Form

    • Constructor Detail

      • MedianOfWidestDimension

        public MedianOfWidestDimension()
        Constructor.

      • MedianOfWidestDimension

        public MedianOfWidestDimension​(int[] instList,
                               Instances insts,
                               EuclideanDistance e)
        Constructor.
        Parameters:
        instList - The master index array.
        insts - The instances on which the tree is (or is to be) built.
        e - The Euclidean distance function to use for splitting.

    • Method Detail

      • globalInfo

        public java.lang.String globalInfo()
        Returns a string describing this nearest neighbour search algorithm.
        Returns:
        a description of the algorithm 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

      • splitNode

        public void splitNode​(BallNode node,
                      int numNodesCreated)
               throws java.lang.Exception
        Splits a ball into two.
        Specified by:
        splitNode in class BallSplitter
        Parameters:
        node - The node to split.
        numNodesCreated - The number of nodes that so far have been created for the tree, so that the newly created nodes are assigned correct/meaningful node numbers/ids.
        Throws:
        java.lang.Exception - If there is some problem in splitting the given node.

      • select

        public int select​(int attIdx,
                  int[] indices,
                  int left,
                  int right,
                  int k)
        Implements computation of the kth-smallest element according to Manber's "Introduction to Algorithms".
        Parameters:
        attIdx - The dimension/attribute of the instances in which to find the kth-smallest element.
        indices - The master index array containing indices of the instances.
        left - The begining index of the portion of the master index array in which to find the kth-smallest element.
        right - The end index of the portion of the master index array in which to find the kth-smallest element.
        k - The value of k
        Returns:
        The index of the kth-smallest element

      • normalizeDimWidthsTipText

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

      • setNormalizeDimWidths

        public void setNormalizeDimWidths​(boolean normalize)
        Should we normalize the widths(ranges) of the dimensions (attributes) before selecting the widest one.
        Parameters:
        normalize - Should be true if the widths are to be normalized.

      • getNormalizeDimWidths

        public boolean getNormalizeDimWidths()
        Whether we are normalizing the widths(ranges) of the dimensions (attributes) or not.
        Returns:
        true if widths are being normalized.

      • listOptions

        public java.util.Enumeration listOptions()
        Returns an enumeration describing the available options.
        Specified by:
        listOptions in interface OptionHandler
        Overrides:
        listOptions in class BallSplitter
        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: 

         -N
  Normalize dimensions' widths.
        Specified by:
        setOptions in interface OptionHandler
        Overrides:
        setOptions in class BallSplitter
        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.
        Specified by:
        getOptions in interface OptionHandler
        Overrides:
        getOptions in class BallSplitter
        Returns:
        An array of strings suitable for passing to setOptions or to be displayed by a GenericObjectEditor.