org.simmetrics

Interface ListDistance<E>

Type Parameters:

E - the type of elements contained in the lists

All Superinterfaces:

Distance<List<E>>

All Known Implementing Classes:

BlockDistance, EuclideanDistance

public interface ListDistance<E>
extends Distance<List<E>>

Measures the distance between two arbitrary lists containing elements of the same type. The measurement results in a value between 0 and 1 inclusive. A value of zero indicates that the lists are dissimilar, a value of 1 indicates they are similar.

The elements in the lists have to implement Object.hashCode() and Object.equals(Object).

The distance measure should be consistent with equals such that a.equals(b) => distance(a,b) == 0.0.

The similarity measure should be reflexive such that distance(a,a) == 0.0.

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

Implementations may not modify the contents of the list. List should be treated as if wrapped by Collections.unmodifiableList(List).

See Also:

Wikipedia - Metric

Method Summary

Modifier and Type	Method and Description
float	distance(List<E> a, List<E> b) Measures the distance between lists a and b.

Method Detail

distance

float distance(List<E> a,
               List<E> b)

Measures the distance between lists a and b. The measurement results in a non-negative value. A value of 0.0 indicates that a and b are similar.

Specified by:

distance in interface Distance<List<E>>

Parameters:

a - list a to compare

b - list b to compare

Returns:

a non-negative value

Throws:

NullPointerException - when either a or b is null