net.sf.javaml.distance
Class JaccardIndexSimilarity

java.lang.Object
  net.sf.javaml.distance.AbstractSimilarity
      net.sf.javaml.distance.JaccardIndexSimilarity

All Implemented Interfaces:

java.io.Serializable, DistanceMeasure

public class JaccardIndexSimilarity
extends AbstractSimilarity

Jaccard index. The distance between two sets is computed in the following way:

               n1 + n2 - 2*n12 
 D(S1, S2) = ------------------ 
               n1 + n2 - n12
               
               
 

 D(S1,S2) = |S1 ^ S2|
            ---------
            |S1 u S2|
 

Where n1 and n2 are the numbers of elements in sets S1 and S2, respectively, and n12 is the number that is in both sets (section).

Version:

%SVN.VERSION%

Author:

Thomas Abeel (thomas@abeel.be)

See Also:

Serialized Form

Constructor Summary

JaccardIndexSimilarity()

Method Summary

double

measure(Instance a, Instance b) Calculates the distance between two instances.

Methods inherited from class net.sf.javaml.distance.AbstractSimilarity

compare

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

JaccardIndexSimilarity

public JaccardIndexSimilarity()

Method Detail

measure

public double measure(Instance a,
                      Instance b)

Description copied from interface: DistanceMeasure

Calculates the distance between two instances.

Returns:

the distance between the two instances