es.upm.etsisi.cf4j.recommender.knn.userSimilarityMetric

Class Singularities

java.lang.Object

es.upm.etsisi.cf4j.recommender.knn.userSimilarityMetric.UserSimilarityMetric

es.upm.etsisi.cf4j.recommender.knn.userSimilarityMetric.Singularities

All Implemented Interfaces:

Partible<User>

public class Singularities
extends UserSimilarityMetric

Implements the following CF similarity metric: Bobadilla, J., Ortega, F., & Hernando, A. (2012). A collaborative filtering similarity measure based on singularities, Information Processing and Management, 48 (2), 204-217.

Field Summary

Fields inherited from class es.upm.etsisi.cf4j.recommender.knn.userSimilarityMetric.UserSimilarityMetric

datamodel, similarities

Constructor Summary

Constructors

Constructor and Description
Singularities(double[] relevantRatings, double[] notRelevantRatings) Constructor of the similarity metric

Method Summary

Modifier and Type	Method and Description
void	beforeRun() Is executed once before execute the method 'exec'.
double	similarity(User user, User otherUser) This method must returns the similarity between two users.
String	toString()

Methods inherited from class es.upm.etsisi.cf4j.recommender.knn.userSimilarityMetric.UserSimilarityMetric

afterRun, getSimilarities, run, setDatamodel

Methods inherited from class java.lang.Object

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

Constructor Detail

Singularities

public Singularities(double[] relevantRatings,
                     double[] notRelevantRatings)

Constructor of the similarity metric

Parameters:

relevantRatings - Relevant ratings array

notRelevantRatings - Not relevant ratings array

Method Detail

beforeRun

public void beforeRun()

Description copied from interface: Partible

Is executed once before execute the method 'exec'. It can be used to initialize resources.

Specified by:

beforeRun in interface Partible<User>

Overrides:

beforeRun in class UserSimilarityMetric

similarity

public double similarity(User user,
                         User otherUser)

Description copied from class: UserSimilarityMetric

This method must returns the similarity between two users.

If two users do not have a similarity value, the method must return Double.NEGATIVE_INFINITY.

The value returned by this method should be higher the greater the similarity between users.

Specified by:

similarity in class UserSimilarityMetric

Parameters:

user - A user

otherUser - Other user

Returns:

Similarity between user and otherUser

toString

public String toString()

Overrides:

toString in class UserSimilarityMetric