Package weka.core

Class MinkowskiDistance

  • All Implemented Interfaces:
    java.io.Serializable, java.lang.Cloneable, DistanceFunction, OptionHandler, RevisionHandler, TechnicalInformationHandler
    public class MinkowskiDistance
extends NormalizableDistance
implements java.lang.Cloneable, TechnicalInformationHandler
    Implementing Minkowski distance (or similarity) function.

    One object defines not one distance but the data model in which the distances between objects of that data model can be computed.

    Attention: For efficiency reasons the use of consistency checks (like are the data models of the two instances exactly the same), is low.

    For more information, see:

    Wikipedia. Minkowski distance. URL http://en.wikipedia.org/wiki/Minkowski_distance.

    BibTeX: 

     @misc{missing_id,
    author = {Wikipedia},
    title = {Minkowski distance},
    URL = {http://en.wikipedia.org/wiki/Minkowski_distance}
 }

    Valid options are: 

     -P <order>
  The order 'p'. With '1' being the Manhattan distance and '2'
  the Euclidean distance.
  (default: 2)
 
     -D
  Turns off the normalization of attribute 
  values in distance calculation.
 
     -R <col1,col2-col4,...>
  Specifies list of columns to used in the calculation of the 
  distance. 'first' and 'last' are valid indices.
  (default: first-last)
 
     -V
  Invert matching sense of column indices.
    Version:
    $Revision: 10203 $
    Author:
    FracPete (fracpete at waikato dot ac dot nz)
    See Also:
    Serialized Form

    • Constructor Detail

      • MinkowskiDistance

        public MinkowskiDistance()
        Constructs an Minkowski Distance object, Instances must be still set.

      • MinkowskiDistance

        public MinkowskiDistance​(Instances data)
        Constructs an Minkowski Distance object and automatically initializes the ranges.
        Parameters:
        data - the instances the distance function should work on

    • Method Detail

      • globalInfo

        public java.lang.String globalInfo()
        Returns a string describing this object.
        Specified by:
        globalInfo in class NormalizableDistance
        Returns:
        a description of the evaluator 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

      • setOptions

        public void setOptions​(java.lang.String[] options)
                throws java.lang.Exception
        Parses a given list of options.
        Specified by:
        setOptions in interface OptionHandler
        Overrides:
        setOptions in class NormalizableDistance
        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 this object.
        Specified by:
        getOptions in interface OptionHandler
        Overrides:
        getOptions in class NormalizableDistance
        Returns:
        an array of strings suitable for passing to setOptions

      • orderTipText

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

      • setOrder

        public void setOrder​(double value)
        Sets the order.
        Parameters:
        value - the new order

      • getOrder

        public double getOrder()
        Gets the order.
        Returns:
        the order

      • distance

        public double distance​(Instance first,
                       Instance second)
        Calculates the distance between two instances.
        Specified by:
        distance in interface DistanceFunction
        Overrides:
        distance in class NormalizableDistance
        Parameters:
        first - the first instance
        second - the second instance
        Returns:
        the distance between the two given instances

      • distance

        public double distance​(Instance first,
                       Instance second,
                       PerformanceStats stats)
        Calculates the distance (or similarity) between two instances. Need to pass this returned distance later on to postprocess method to set it on correct scale.
        P.S.: Please don't mix the use of this function with distance(Instance first, Instance second), as that already does post processing. Please consider passing Double.POSITIVE_INFINITY as the cutOffValue to this function and then later on do the post processing on all the distances.
        Specified by:
        distance in interface DistanceFunction
        Overrides:
        distance in class NormalizableDistance
        Parameters:
        first - the first instance
        second - the second instance
        stats - the structure for storing performance statistics.
        Returns:
        the distance between the two given instances or Double.POSITIVE_INFINITY.

      • postProcessDistances

        public void postProcessDistances​(double[] distances)
        Does post processing of the distances (if necessary) returned by distance(distance(Instance first, Instance second, double cutOffValue). It is necessary to do so to get the correct distances if distance(distance(Instance first, Instance second, double cutOffValue) is used. This is because that function actually returns the squared distance to avoid inaccuracies arising from floating point comparison.
        Specified by:
        postProcessDistances in interface DistanceFunction
        Overrides:
        postProcessDistances in class NormalizableDistance
        Parameters:
        distances - the distances to post-process

      • getRevision

        public java.lang.String getRevision()
        Returns the revision string.
        Specified by:
        getRevision in interface RevisionHandler
        Returns:
        the revision