org.apache.mahout.cf.taste.impl.recommender.svd

Class SVDPlusPlusFactorizer

java.lang.Object

org.apache.mahout.cf.taste.impl.recommender.svd.AbstractFactorizer

org.apache.mahout.cf.taste.impl.recommender.svd.RatingSGDFactorizer

org.apache.mahout.cf.taste.impl.recommender.svd.SVDPlusPlusFactorizer

All Implemented Interfaces:

Refreshable, Factorizer

public final class SVDPlusPlusFactorizer
extends RatingSGDFactorizer

SVD++, an enhancement of classical matrix factorization for rating prediction. Additionally to using ratings (how did people rate?) for learning, this model also takes into account who rated what. Yehuda Koren: Factorization Meets the Neighborhood: a Multifaceted Collaborative Filtering Model, KDD 2008. http://research.yahoo.com/files/kdd08koren.pdf

Field Summary

Fields inherited from class org.apache.mahout.cf.taste.impl.recommender.svd.RatingSGDFactorizer

biasLearningRate, biasReg, dataModel, FEATURE_OFFSET, ITEM_BIAS_INDEX, itemVectors, learningRate, learningRateDecay, numFeatures, preventOverfitting, randomNoise, USER_BIAS_INDEX, userVectors

Constructor Summary

Constructors

Constructor and Description
SVDPlusPlusFactorizer(DataModel dataModel, int numFeatures, double learningRate, double preventOverfitting, double randomNoise, int numIterations, double learningRateDecay)
SVDPlusPlusFactorizer(DataModel dataModel, int numFeatures, int numIterations)

Method Summary

Modifier and Type	Method and Description
Factorization	factorize()
protected void	prepareTraining()
protected void	updateParameters(long userID, long itemID, float rating, double currentLearningRate)

Methods inherited from class org.apache.mahout.cf.taste.impl.recommender.svd.RatingSGDFactorizer

shufflePreferences

Methods inherited from class org.apache.mahout.cf.taste.impl.recommender.svd.AbstractFactorizer

createFactorization, itemIndex, refresh, userIndex

Methods inherited from class java.lang.Object

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

Constructor Detail

SVDPlusPlusFactorizer

public SVDPlusPlusFactorizer(DataModel dataModel,
                             int numFeatures,
                             int numIterations)
                      throws TasteException

Throws:

TasteException

SVDPlusPlusFactorizer

public SVDPlusPlusFactorizer(DataModel dataModel,
                             int numFeatures,
                             double learningRate,
                             double preventOverfitting,
                             double randomNoise,
                             int numIterations,
                             double learningRateDecay)
                      throws TasteException

Throws:

TasteException

Method Detail

prepareTraining

protected void prepareTraining()
                        throws TasteException

Overrides:

prepareTraining in class RatingSGDFactorizer

Throws:

TasteException

factorize

public Factorization factorize()
                        throws TasteException

Specified by:

factorize in interface Factorizer

Overrides:

factorize in class RatingSGDFactorizer

Throws:

TasteException

updateParameters

protected void updateParameters(long userID,
                                long itemID,
                                float rating,
                                double currentLearningRate)

Overrides:

updateParameters in class RatingSGDFactorizer