Package weka.core.neighboursearch.balltrees

Class MedianOfWidestDimension

java.lang.Object
weka.core.neighboursearch.balltrees.BallSplitter
weka.core.neighboursearch.balltrees.MedianOfWidestDimension
All Implemented Interfaces:
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: 10203 $
Author:
Ashraf M. Kibriya (amk14[at-the-rate]cs[dot]waikato[dot]ac[dot]nz)
See Also:

  • Constructor Details

    • 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 Details

    • globalInfo

      public 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 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:
      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 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 Enumeration<Option> 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(String[] options) throws 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:
      Exception - if an option is not supported

    • getOptions

      public 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.

    • getRevision

      public String getRevision()
      Returns the revision string.
      Specified by:
      getRevision in interface RevisionHandler
      Overrides:
      getRevision in class BallSplitter
      Returns:
      the revision