org.grouplens.lenskit.baseline

Class LeastSquaresItemScorer

java.lang.Object

org.grouplens.lenskit.basic.AbstractItemScorer

org.grouplens.lenskit.baseline.LeastSquaresItemScorer

All Implemented Interfaces:

Serializable, ItemScorer

@DefaultProvider(value=LeastSquaresItemScorer.Builder.class)
 @Shareable
public class LeastSquaresItemScorer
extends AbstractItemScorer
implements 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(ImmutableSparseVector uoff, ImmutableSparseVector ioff, double mean) Construct a new least-squares scorer.

Method Summary

Modifier and Type	Method and Description
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

Constructor Detail

LeastSquaresItemScorer

public LeastSquaresItemScorer(ImmutableSparseVector uoff,
                              ImmutableSparseVector ioff,
                              double mean)

Construct a new least-squares scorer.

Parameters:

uoff - the user offsets

ioff - the item offsets

mean - the global mean rating

Method Detail

score

public void score(long user,
                  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.

Specified by:

score in interface ItemScorer

Parameters:

user - The user ID.

output - The score vector.