org.simmetrics.metrics

Class JaccardSimilarity<T>

java.lang.Object

org.simmetrics.metrics.JaccardSimilarity<T>

Type Parameters:

T - type of the token

All Implemented Interfaces:

Metric<Set<T>>, SetMetric<T>

public final class JaccardSimilarity<T>
extends Object
implements SetMetric<T>

Jaccard similarity algorithm providing a similarity measure between two sets using the vector space of presented tokens.

jaccard index(a,b) = ( |a & b| ) / ( | a or b | )

This metric is identical to the matching coefficient which operates on lists.

This class is immutable and thread-safe.

See Also:

Wikipedia - Jaccard index

Constructor Summary

Constructors

Constructor and Description
JaccardSimilarity()

Method Summary

Modifier and Type	Method and Description
float	compare(Set<T> a, Set<T> b) Measures the similarity between sets a and b.
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

JaccardSimilarity

public JaccardSimilarity()

Method Detail

compare

public float compare(Set<T> a,
                     Set<T> b)

Description copied from interface: SetMetric

Measures the similarity between sets a and b. The measurement results in a value between 0 and 1 inclusive. A value of zero indicates that the sets are dissimilar, a value of 1 indicates they are similar.

Specified by:

compare in interface Metric<Set<T>>

Specified by:

compare in interface SetMetric<T>

Parameters:

a - set a to compare

b - set b to compare

Returns:

a value between 0 and 1 inclusive indicating similarity

toString

public String toString()

Overrides:

toString in class Object