es.upm.etsisi.cf4j.qualityMeasure.recommendation

Class Precision

java.lang.Object

es.upm.etsisi.cf4j.qualityMeasure.QualityMeasure

es.upm.etsisi.cf4j.qualityMeasure.recommendation.Precision

public class Precision
extends QualityMeasure

This class calculates the precision of the recommendations performed by a Recommender. It is calculated as follows:

precision = <relevant recommended items> / <number of recommended items>

Field Summary

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

recommender

Constructor Summary

Constructors

Constructor and Description
Precision(Recommender recommender, int numberOfRecommendations, double relevantThreshold) Constructor of Precision
Precision(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

Precision

public Precision(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 Precision are going to be computed

params - Quality measure's parameters

Precision

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

Constructor of Precision

Parameters:

recommender - Recommender instance for which the precision 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