org.simmetrics

Interface Metric<T>

Type Parameters:

T - type of the elements compared

All Known Subinterfaces:

ListMetric<T>, SetMetric<T>, StringMetric

All Known Implementing Classes:

BlockDistance, CosineSimilarity, DamerauLevenshtein, DiceSimilarity, EuclideanDistance, Identity, JaccardSimilarity, Jaro, JaroWinkler, Levenshtein, MatchingCoefficient, MongeElkan, NeedlemanWunch, OverlapCoefficient, SimonWhite, SmithWaterman, SmithWatermanGotoh

public interface Metric<T>

Measures the similarity between two arbitrary objects of the same type . 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.

The similarity measure should be consistent with equals such that a.equals(b) => compare(a,b) == 1.0.

The similarity measure should be reflexive such that compare(a,a) == 1.0.

The similarity measure should be symmetric such that compare(a,b) == compare(b,a).

The similarity measure may be transitive such that 1.0 - compare(a, c) ≤ 1.0 - compare(a, b) + 1.0 - compare(b, c)

The similarity measure may satisfy the coincidence axiom such that compare(a, b) = 0 if and only if a.equals(b)

Implementations may not modify the arguments. Arguments should be treated as if they were unmodifiable.

See Also:

Wikipedia - Metric

Method Summary

Modifier and Type	Method and Description
float	compare(T a, T b) Measures the similarity between a and b.

Method Detail

compare

float compare(T a,
              T b)

Measures the similarity between a and b. The measurement results in a value between 0 and 1 inclusive. A value of 0.0 indicates that a and b are dissimilar, a value of 1.0 indicates they are similar.

Parameters:

a - object a to compare

b - object b to compare

Returns:

a value between 0 and 1 inclusive indicating similarity

Throws:

NullPointerException - when either a or b is null