es.upm.etsisi.cf4j.recommender.knn.itemSimilarityMetric

Class Singularities

java.lang.Object

es.upm.etsisi.cf4j.recommender.knn.itemSimilarityMetric.ItemSimilarityMetric

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

All Implemented Interfaces:

Partible<Item>

public class Singularities
extends ItemSimilarityMetric

This class implements the singularities CF similarity metric. The similarity metric is described here: 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.itemSimilarityMetric.ItemSimilarityMetric

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(Item item, Item otherItem) This method must returns the similarity between two items.
String	toString()

Methods inherited from class es.upm.etsisi.cf4j.recommender.knn.itemSimilarityMetric.ItemSimilarityMetric

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<Item>

Overrides:

beforeRun in class ItemSimilarityMetric

similarity

public double similarity(Item item,
                         Item otherItem)

Description copied from class: ItemSimilarityMetric

This method must returns the similarity between two items.

If two items 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 items.

Specified by:

similarity in class ItemSimilarityMetric

Parameters:

item - An item

otherItem - Other item

Returns:

Similarity between item and otherItem

toString

public String toString()

Overrides:

toString in class ItemSimilarityMetric