/*
* File: SimilarityFunction.java
* Authors: Justin Basilico
* Company: Sandia National Laboratories
* Project: Cognitive Foundry
*
* Copyright January 19, 2009, Sandia Corporation.
* Under the terms of Contract DE-AC04-94AL85000, there is a non-exclusive
* license for use of this work by or on behalf of the U.S. Government. Export
* of this program may require a license from the United States Government.
* See CopyrightHistory.txt for complete details.
*
*/
package gov.sandia.cognition.text.relation;
import gov.sandia.cognition.math.DivergenceFunction;
/**
* Defines the functionality of a similarity function that computes the
* similarity between two objects.
*
* @param <FromType>
* The type that the similarity is from.
* @param <ToType>
* The type that the similarity is to.
* @author Justin Basilico
* @since 3.0
*/
public interface SimilarityFunction<FromType, ToType>
{
/**
* Evaluates the similarity between the two given objects. Similarity
* between two objects is high if those objects are similar and low if they
* are not similar. Typically, this is a value that is greater than or
* equal to zero that is higher the more similar two objects are. If the
* two types are the same, then the rule f(x, y) = f(y, x) must apply.
*
* @param from
* The object the similarity is from.
* @param to
* The object the similarity is to.
* @return
* The similarity between the two objects.
*/
public double evaluate(
final FromType from,
final ToType to);
/**
* Converts the similarity function into a divergence function. A diverge
*
* @return
* The divergence function version of this similarity function.
*/
public DivergenceFunction<FromType, ToType> asDivergence();
}