org.lenskit.baseline

Class LeastSquaresItemScorer

java.lang.Object

org.lenskit.basic.AbstractItemScorer

org.lenskit.baseline.LeastSquaresItemScorer

All Implemented Interfaces:

java.io.Serializable, ItemScorer

@DefaultProvider(value=LeastSquaresItemScorer.Builder.class)
 @Shareable
public class LeastSquaresItemScorer
extends AbstractItemScorer
implements java.io.Serializable

Baseline scorer using least-squares estimates of preferences, trained by gradient descent.

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	LeastSquaresItemScorer.Builder The builder for the least squares predictor.

Constructor Summary

Constructors

Constructor and Description
LeastSquaresItemScorer(Long2DoubleMap ubs, Long2DoubleMap ibs, double mean) Construct a new least-squares scorer.

Method Summary

Modifier and Type	Method and Description
ResultMap	scoreWithDetails(long user, java.util.Collection<java.lang.Long> items) Score a collection of items and potentially return more details on the scores.

Methods inherited from class org.lenskit.basic.AbstractItemScorer

score, score

Methods inherited from class java.lang.Object

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

Constructor Detail

LeastSquaresItemScorer

public LeastSquaresItemScorer(Long2DoubleMap ubs,
                              Long2DoubleMap ibs,
                              double mean)

Construct a new least-squares scorer.

Parameters:

ubs - the user biases

ibs - the item biases

mean - the global mean rating

Method Detail

scoreWithDetails

@Nonnull
public ResultMap scoreWithDetails(long user,
                                           @Nonnull
                                           java.util.Collection<java.lang.Long> items)

Description copied from interface: ItemScorer

Score a collection of items and potentially return more details on the scores.

Specified by:

scoreWithDetails in interface ItemScorer

Parameters:

user - The user ID for whom to generate scores.

items - The item to score.

Returns:

The scores for the items. This result set may not contain all requested items. Implementations that support additional details will return a subclass of ResultMap that provides access to those details.