org.grouplens.lenskit.slopeone

Class SlopeOneItemScorer

java.lang.Object

org.grouplens.lenskit.basic.AbstractItemScorer

org.grouplens.lenskit.slopeone.SlopeOneItemScorer

All Implemented Interfaces:

ItemScorer

Direct Known Subclasses:

WeightedSlopeOneItemScorer

public class SlopeOneItemScorer
extends AbstractItemScorer

An ItemScorer that implements the Slope One algorithm.

Field Summary

Fields

Modifier and Type	Field and Description
protected PreferenceDomain	domain
protected SlopeOneModel	model

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

dao

Constructor Summary

Constructors

Constructor and Description
SlopeOneItemScorer(DataAccessObject dao, SlopeOneModel model, PreferenceDomain dom)

Method Summary

Methods

Modifier and Type	Method and Description
SlopeOneModel	getModel()
void	score(UserHistory<? extends Event> history, MutableSparseVector scores) Score items in a vector.

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

canUseHistory, getUserHistory, score, score, score, score, score

Methods inherited from class java.lang.Object

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

Field Detail

model

protected SlopeOneModel model

domain

protected final PreferenceDomain domain

Constructor Detail

SlopeOneItemScorer

@Inject
public SlopeOneItemScorer(DataAccessObject dao,
                         SlopeOneModel model,
                         @Nullable
                         PreferenceDomain dom)

Method Detail

score

public void score(@Nonnull
         UserHistory<? extends Event> history,
         @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.

If the user has rated any items to be scored, the algorithm should not just use their rating as the score — it should compute a score in the normal fashion. If client code wants to substitute ratings, it is easy to do so as a separate step or wrapper interface.

Parameters:

history - The user history.

scores - The score vector.

getModel

public SlopeOneModel getModel()