org.grouplens.lenskit.basic

Class AbstractItemScorer

java.lang.Object

org.grouplens.lenskit.basic.AbstractItemScorer

All Implemented Interfaces:

ItemScorer

Direct Known Subclasses:

BiasedMFItemScorer, FallbackItemScorer, FunkSVDItemScorer, ItemItemScorer, ItemMeanRatingItemScorer, LeastSquaresItemScorer, PrecomputedItemScorer, SimpleCachingItemScorer, SlopeOneItemScorer, UserMeanItemScorer, UserUserItemScorer

public abstract class AbstractItemScorer
extends Object
implements ItemScorer

Base class to make item scorers easier to implement. Delegates all score methods to ItemScorer.score(long, MutableSparseVector).

Constructor Summary

Constructors

Constructor and Description
AbstractItemScorer()

Method Summary

Modifier and Type	Method and Description
SparseVector	score(long user, Collection<Long> items) Score a collection of items.
double	score(long user, long item) Score a single item.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.grouplens.lenskit.ItemScorer

score

Constructor Detail

AbstractItemScorer

public AbstractItemScorer()

Method Detail

score

@Nonnull
public SparseVector score(long user,
                                   @Nonnull
                                   Collection<Long> items)

Score a collection of items.

Delegates to ItemScorer.score(long, MutableSparseVector).

Specified by:

score in interface ItemScorer

Parameters:

user - The user ID for whom to generate scores.

items - The item to score.

Returns:

A mapping from item IDs to predicted preference. This mapping may not contain all requested items.

score

public double score(long user,
                    long item)

Score a single item.

Delegates to score(long, Collection).

Specified by:

score in interface ItemScorer

Parameters:

user - The user ID for whom to generate a score.

item - The item ID to score.

Returns:

The score, or Double.NaN if no score can be generated.