org.grouplens.lenskit.baseline

Class FallbackItemScorer

java.lang.Object

org.grouplens.lenskit.basic.AbstractItemScorer

org.grouplens.lenskit.baseline.FallbackItemScorer

All Implemented Interfaces:

ItemScorer

public class FallbackItemScorer
extends AbstractItemScorer

Item scorer that combines a primary scorer with a baseline. This scorer is comprised of two other scorers, a primary scorer and a baseline scorer. It first scores items using the primary scorer, and then consults the baseline scorer for any items that the primary scorer could not score.

Field Summary

Fields

Modifier and Type	Field and Description
static TypedSymbol<ScoreSource>	SCORE_SOURCE_SYMBOL

Constructor Summary

Constructors

Constructor and Description
FallbackItemScorer(ItemScorer primary, ItemScorer baseline)

Method Summary

Modifier and Type	Method and Description
ItemScorer	getBaselineScorer() Get the baseline scorer from this item scorer.
ItemScorer	getPrimaryScorer() Get the primary scorer from this item scorer.
void	score(long user, MutableSparseVector output) 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

SCORE_SOURCE_SYMBOL

public static final TypedSymbol<ScoreSource> SCORE_SOURCE_SYMBOL

Constructor Detail

FallbackItemScorer

@Inject
public FallbackItemScorer(@PrimaryScorer
                                  ItemScorer primary,
                                  @BaselineScorer
                                  ItemScorer baseline)

Method Detail

score

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

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.

output - The score vector.

getPrimaryScorer

@Nonnull
public ItemScorer getPrimaryScorer()

Get the primary scorer from this item scorer.

Returns:

The scorer's primary scorer.

See Also:

PrimaryScorer

getBaselineScorer

@Nonnull
public ItemScorer getBaselineScorer()

Get the baseline scorer from this item scorer.

Returns:

The scorer's baseline scorer.

See Also:

BaselineScorer