es.uam.eps.ir.ranksys.mf.plsa

Class PLSAFactorizer<U,I>

java.lang.Object

es.uam.eps.ir.ranksys.mf.Factorizer<U,I>

es.uam.eps.ir.ranksys.mf.plsa.PLSAFactorizer<U,I>

Type Parameters:

U - type of the users

I - type of the items

public class PLSAFactorizer<U,I>
extends Factorizer<U,I>

Probabilistic Latent Semantic Analysis of Hofmann. T. Hofmann. Latent Semantic Models for Collaborative Filtering. ToIS, Vol 22 No. 1, January 2004.

Author:

Saúl Vargas (saul.vargas@uam.es)

Constructor Summary

Constructors

Constructor and Description
PLSAFactorizer(int numIter) Constructor.

Method Summary

Modifier and Type	Method and Description
double	error(Factorization<U,I> factorization, FastPreferenceData<U,I> data) Global loss of the factorization.
void	factorize(Factorization<U,I> factorization, FastPreferenceData<U,I> data) Calculates the factorization by using a previously generate matrix factorization.
Factorization<U,I>	factorize(int K, FastPreferenceData<U,I> data) Creates and calculates a factorization.

Methods inherited from class java.lang.Object

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

Constructor Detail

PLSAFactorizer

public PLSAFactorizer(int numIter)

Constructor.

Parameters:

numIter - number of expectation-maximization steps

Method Detail

error

public double error(Factorization<U,I> factorization,
                    FastPreferenceData<U,I> data)

Description copied from class: Factorizer

Global loss of the factorization.

Specified by:

error in class Factorizer<U,I>

Parameters:

factorization - matrix factorization

data - preference data

Returns:

the global loss

factorize

public Factorization<U,I> factorize(int K,
                                    FastPreferenceData<U,I> data)

Description copied from class: Factorizer

Creates and calculates a factorization.

Specified by:

factorize in class Factorizer<U,I>

Parameters:

K - size of the latent feature space.

data - preference data

Returns:

a matrix factorization

factorize

public void factorize(Factorization<U,I> factorization,
                      FastPreferenceData<U,I> data)

Description copied from class: Factorizer

Calculates the factorization by using a previously generate matrix factorization.

Specified by:

factorize in class Factorizer<U,I>

Parameters:

factorization - matrix factorization

data - preference data