org.grouplens.lenskit.mf.funksvd

Class FunkSVDItemScorer

java.lang.Object

org.grouplens.lenskit.basic.AbstractItemScorer

org.grouplens.lenskit.mf.funksvd.FunkSVDItemScorer

All Implemented Interfaces:

ItemScorer

public class FunkSVDItemScorer
extends AbstractItemScorer

Do recommendations and predictions based on SVD matrix factorization. Recommendation is done based on folding-in. The strategy is do a fold-in operation as described in Sarwar et al., 2002 with the user's ratings.

Field Summary

Fields

Modifier and Type	Field and Description
protected BiasedMFKernel	kernel
protected FunkSVDModel	model

Constructor Summary

Constructors

Constructor and Description
FunkSVDItemScorer(UserEventDAO dao, FunkSVDModel model, ItemScorer baseline, PreferenceDomain dom, FunkSVDUpdateRule rule) Construct the item scorer.

Method Summary

Modifier and Type	Method and Description
FunkSVDUpdateRule	getUpdateRule()
void	score(long user, MutableSparseVector scores) Score items in a vector.

Methods inherited from class org.grouplens.lenskit.basic.AbstractItemScorer

score, score

Methods inherited from class java.lang.Object

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

Field Detail

model

protected final FunkSVDModel model

kernel

protected final BiasedMFKernel kernel

Constructor Detail

FunkSVDItemScorer

@Inject
public FunkSVDItemScorer(UserEventDAO dao,
                                 FunkSVDModel model,
                                 @BaselineScorer
                                 ItemScorer baseline,
                                 @Nullable
                                 PreferenceDomain dom,
                                 @Nullable @RuntimeUpdate
                                 FunkSVDUpdateRule rule)

Construct the item scorer.

Parameters:

dao - The DAO.

model - The model.

baseline - The baseline scorer. Be very careful when configuring a different baseline at runtime than at model-build time; such a configuration is unlikely to perform well.

rule - The update rule, or null (the default) to only use the user features from the model. If provided, this update rule is used to update a user's feature values based on their profile when scores are requested.

Method Detail

getUpdateRule

@Nullable
public FunkSVDUpdateRule getUpdateRule()

score

public void score(long user,
                  @Nonnull
                  MutableSparseVector scores)

Description copied from interface: ItemScorer

Score items in a vector. The key domain of the provided vector is the items to score, and the score method sets the values for each item to its score (or unsets it, if no score can be provided). The previous values are discarded.

Parameters:

user - The user ID.

scores - The score vector.