org.grouplens.lenskit.baseline

Class GlobalMeanRatingItemScorer

java.lang.Object

org.grouplens.lenskit.baseline.ConstantItemScorer

org.grouplens.lenskit.baseline.GlobalMeanRatingItemScorer

All Implemented Interfaces:

Serializable, ItemScorer

@DefaultProvider(value=GlobalMeanRatingItemScorer.Builder.class)
 @Shareable
public class GlobalMeanRatingItemScorer
extends ConstantItemScorer

Rating scorer that predicts the global mean rating for all items.

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	GlobalMeanRatingItemScorer.Builder A default builder used to create GlobalMeanPredictors.

Nested classes/interfaces inherited from class org.grouplens.lenskit.baseline.ConstantItemScorer

ConstantItemScorer.Value

Constructor Summary

Constructors

Constructor and Description
GlobalMeanRatingItemScorer(double mean) Construct a new global mean scorer where it is assumed that the given value is the global mean.

Method Summary

Modifier and Type	Method and Description
static double	computeMeanRating(EventDAO dao) Utility method to compute the mean or average of the rating values contained in the given collection of ratings.

Methods inherited from class org.grouplens.lenskit.baseline.ConstantItemScorer

score, score, score, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

GlobalMeanRatingItemScorer

public GlobalMeanRatingItemScorer(double mean)

Construct a new global mean scorer where it is assumed that the given value is the global mean.

Parameters:

mean - The global mean.

Method Detail

computeMeanRating

public static double computeMeanRating(EventDAO dao)

Utility method to compute the mean or average of the rating values contained in the given collection of ratings.

Parameters:

dao - The DAO to average.

Returns:

The average of the rating values stored in ratings.