es.upm.etsisi.cf4j.qualityMeasure.recommendation

Class F1

java.lang.Object

es.upm.etsisi.cf4j.qualityMeasure.QualityMeasure

es.upm.etsisi.cf4j.qualityMeasure.recommendation.F1

public class F1
extends QualityMeasure

This class calculates the F1 score of the recommender system. F1 score is computed as follows:

F1 = 2 * precision * recall / (precision + recall)

Field Summary

Fields inherited from class es.upm.etsisi.cf4j.qualityMeasure.QualityMeasure

recommender

Constructor Summary

Constructors

Constructor and Description
F1(Recommender recommender, int numberOfRecommendations, double relevantThreshold) Constructor
F1(Recommender recommender, Map<String,Object> params) Constructor from a Map object with the quality measure parameters.

Method Summary

Modifier and Type	Method and Description
protected double	getScore(TestUser testUser, double[] predictions) Computes the quality measure score for a TestUser given the predictions for his/her test ratings

Methods inherited from class es.upm.etsisi.cf4j.qualityMeasure.QualityMeasure

getScore, getScore

Methods inherited from class java.lang.Object

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

Constructor Detail

F1

public F1(Recommender recommender,
          Map<String,Object> params)

Constructor from a Map object with the quality measure parameters. Map object must contains the following keys:

• numberOfRecommendations: int value with the number of items to be recommended.
• relevantThreshold:: double value with the minimum rating to consider a test rating as relevant.

Parameters:

recommender - Recommender instance for which the F1 are going to be computed

params - Quality measure's parameters

F1

public F1(Recommender recommender,
          int numberOfRecommendations,
          double relevantThreshold)

Constructor

Parameters:

recommender - Recommender instance for which the F1 are going to be computed

numberOfRecommendations - Number of recommendations

relevantThreshold - Minimum rating to consider a rating as relevant

Method Detail

getScore

protected double getScore(TestUser testUser,
                          double[] predictions)

Description copied from class: QualityMeasure

Computes the quality measure score for a TestUser given the predictions for his/her test ratings

Specified by:

getScore in class QualityMeasure

Parameters:

testUser - TestUser for which the quality measure score is computed

predictions - Prediction value for the test items rated by the test user

Returns:

Quality measure score