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

Class MSD

java.lang.Object

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

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

All Implemented Interfaces:

Partible<Item>

public class MSD
extends ItemSimilarityMetric

Implements traditional MSD as CF similarity metric for items. The returned value is 1 - MSD.

Field Summary

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

datamodel, similarities

Constructor Summary

Constructors

Constructor	Description
MSD()

Method Summary

Modifier and Type	Method	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.

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

afterRun, getSimilarities, run, setDatamodel, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

MSD

public MSD()

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