Package weka.core.neighboursearch

Class LinearNNSearch

java.lang.Object
weka.core.neighboursearch.NearestNeighbourSearch
weka.core.neighboursearch.LinearNNSearch
All Implemented Interfaces:
Serializable, AdditionalMeasureProducer, OptionHandler, RevisionHandler
public class LinearNNSearch extends NearestNeighbourSearch
Class implementing the brute force search algorithm for nearest neighbour search.

Valid options are: 

 -S
  Skip identical instances (distances equal to zero).
Version:
$Revision: 15001 $
Author:
Ashraf M. Kibriya (amk14[at-the-rate]cs[dot]waikato[dot]ac[dot]nz)
See Also:

  • Constructor Details

    • LinearNNSearch

      public LinearNNSearch()
      Constructor. Needs setInstances(Instances) to be called before the class is usable.

    • LinearNNSearch

      public LinearNNSearch(Instances insts)
      Constructor that uses the supplied set of instances.
      Parameters:
      insts - the instances to use

  • Method Details

    • globalInfo

      public String globalInfo()
      Returns a string describing this nearest neighbour search algorithm.
      Overrides:
      globalInfo in class NearestNeighbourSearch
      Returns:
      a description of the algorithm for displaying in the explorer/experimenter gui

    • listOptions

      public Enumeration<Option> listOptions()
      Returns an enumeration describing the available options.
      Specified by:
      listOptions in interface OptionHandler
      Overrides:
      listOptions in class NearestNeighbourSearch
      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: 

       -S
  Skip identical instances (distances equal to zero).
      Specified by:
      setOptions in interface OptionHandler
      Overrides:
      setOptions in class NearestNeighbourSearch
      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 NearestNeighbourSearch
      Returns:
      an array of strings suitable for passing to setOptions()

    • skipIdenticalTipText

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

    • setSkipIdentical

      public void setSkipIdentical(boolean skip)
      Sets the property to skip identical instances (with distance zero from the target) from the set of neighbours returned.
      Parameters:
      skip - if true, identical intances are skipped

    • getSkipIdentical

      public boolean getSkipIdentical()
      Gets whether if identical instances are skipped from the neighbourhood.
      Returns:
      true if identical instances are skipped

    • nearestNeighbour

      public Instance nearestNeighbour(Instance target) throws Exception
      Returns the nearest instance in the current neighbourhood to the supplied instance.
      Specified by:
      nearestNeighbour in class NearestNeighbourSearch
      Parameters:
      target - The instance to find the nearest neighbour for.
      Returns:
      the nearest instance
      Throws:
      Exception - if the nearest neighbour could not be found.

    • kNearestNeighbours

      public Instances kNearestNeighbours(Instance target, int kNN) throws Exception
      Returns k nearest instances in the current neighbourhood to the supplied instance.
      Specified by:
      kNearestNeighbours in class NearestNeighbourSearch
      Parameters:
      target - The instance to find the k nearest neighbours for.
      kNN - The number of nearest neighbours to find.
      Returns:
      the k nearest neighbors
      Throws:
      Exception - if the neighbours could not be found.

    • getDistances

      public double[] getDistances() throws Exception
      Returns the distances of the k nearest neighbours. The kNearestNeighbours or nearestNeighbour must always be called before calling this function. If this function is called before calling either the kNearestNeighbours or the nearestNeighbour, then it throws an exception. If, however, if either of the nearestNeighbour functions are called at any point in the past then no exception is thrown and the distances of the training set from the last supplied target instance (to either one of the nearestNeighbour functions) is/are returned.
      Specified by:
      getDistances in class NearestNeighbourSearch
      Returns:
      array containing the distances of the nearestNeighbours. The length and ordering of the array is the same as that of the instances returned by nearestNeighbour functions.
      Throws:
      Exception - if called before calling kNearestNeighbours or nearestNeighbours.

    • setInstances

      public void setInstances(Instances insts) throws Exception
      Sets the instances comprising the current neighbourhood.
      Overrides:
      setInstances in class NearestNeighbourSearch
      Parameters:
      insts - The set of instances on which the nearest neighbour search is carried out. Usually this set is the training set.
      Throws:
      Exception - if setting of instances fails

    • update

      public void update(Instance ins) throws Exception
      Updates the LinearNNSearch to cater for the new added instance. This implementation only updates the ranges of the DistanceFunction class, since our set of instances is passed by reference and should already have the newly added instance.
      Specified by:
      update in class NearestNeighbourSearch
      Parameters:
      ins - The instance to add. Usually this is the instance that is added to our neighbourhood i.e. the training instances.
      Throws:
      Exception - if the given instances are null

    • addInstanceInfo

      public void addInstanceInfo(Instance ins)
      Adds the given instance info. This implementation updates the range datastructures of the DistanceFunction class.
      Overrides:
      addInstanceInfo in class NearestNeighbourSearch
      Parameters:
      ins - The instance to add the information of. Usually this is the test instance supplied to update the range of attributes in the distance function.

    • getRevision

      public String getRevision()
      Returns the revision string.
      Returns:
      the revision