es.uam.eps.ir.ranksys.mf

Class Factorization<U,I>

java.lang.Object

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

Type Parameters:

U - type of the users

I - type of the items

All Implemented Interfaces:

ItemIndex<I>, UserIndex<U>, FastItemIndex<I>, FastUserIndex<U>

public class Factorization<U,I>
extends Object
implements FastItemIndex<I>, FastUserIndex<U>

Matrix factorization.

Author:

Saúl Vargas (saul.vargas@uam.es)

Field Summary

Fields

Modifier and Type	Field and Description
protected FastItemIndex<I>	iIndex item index
protected cern.colt.matrix.impl.DenseDoubleMatrix2D	itemMatrix item matrix
protected int	K dimensionality of the vector space
protected FastUserIndex<U>	uIndex user index
protected cern.colt.matrix.impl.DenseDoubleMatrix2D	userMatrix user matrix

Constructor Summary

Constructors

Constructor and Description
Factorization(FastUserIndex<U> uIndex, FastItemIndex<I> iIndex, cern.colt.matrix.impl.DenseDoubleMatrix2D userMatrix, cern.colt.matrix.impl.DenseDoubleMatrix2D itemMatrix, int K) Constructor for stored factorizations.
Factorization(FastUserIndex<U> uIndex, FastItemIndex<I> iIndex, int K, cern.colt.function.DoubleFunction initFunction) Constructor.

Method Summary

Modifier and Type	Method and Description
boolean	containsItem(I i) Checks whether the index contains an item.
boolean	containsUser(U u) Checks whether the index contains a user.
cern.colt.matrix.impl.DenseDoubleMatrix2D	getItemMatrix() Returns the whole item matrix.
cern.colt.matrix.DoubleMatrix1D	getItemVector(I i) Returns the row of the item matrix corresponding to the given item.
int	getK() Returns the dimension of the latent feature space.
cern.colt.matrix.impl.DenseDoubleMatrix2D	getUserMatrix() Returns the whole user matrix.
cern.colt.matrix.DoubleMatrix1D	getUserVector(U u) Returns the row of the user matrix corresponding to the given user.
I	iidx2item(int iidx) Returns the item represented with the index.
int	item2iidx(I i) Returns the index assigned to the item.
int	numItems() Counts the number of indexed items.
int	numUsers() Counts the number of indexed users.
U	uidx2user(int uidx) Returns the user represented with the index.
int	user2uidx(U u) Returns the index assigned to the user.

Methods inherited from class java.lang.Object

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

Methods inherited from interface es.uam.eps.ir.ranksys.fast.index.FastItemIndex

getAllIidx, getAllItems, iidx2item, iidx2item, item2iidx, item2iidx

Methods inherited from interface es.uam.eps.ir.ranksys.fast.index.FastUserIndex

getAllUidx, getAllUsers, uidx2user, uidx2user, user2uidx, user2uidx

Field Detail

userMatrix

protected final cern.colt.matrix.impl.DenseDoubleMatrix2D userMatrix

user matrix

itemMatrix

protected final cern.colt.matrix.impl.DenseDoubleMatrix2D itemMatrix

item matrix

K

protected final int K

dimensionality of the vector space

uIndex

protected final FastUserIndex<U> uIndex

user index

iIndex

protected final FastItemIndex<I> iIndex

item index

Constructor Detail

Factorization

public Factorization(FastUserIndex<U> uIndex,
                     FastItemIndex<I> iIndex,
                     int K,
                     cern.colt.function.DoubleFunction initFunction)

Constructor.

Parameters:

uIndex - fast user index

iIndex - fast item index

K - dimension of the latent feature space

initFunction - function to initialize the cells of the matrices

Factorization

public Factorization(FastUserIndex<U> uIndex,
                     FastItemIndex<I> iIndex,
                     cern.colt.matrix.impl.DenseDoubleMatrix2D userMatrix,
                     cern.colt.matrix.impl.DenseDoubleMatrix2D itemMatrix,
                     int K)

Constructor for stored factorizations.

Parameters:

uIndex - fast user index

iIndex - fast item index

userMatrix - user matrix

itemMatrix - item matrix

K - dimension of the latent feature space

Method Detail

numUsers

public int numUsers()

Description copied from interface: UserIndex

Counts the number of indexed users.

Specified by:

numUsers in interface UserIndex<U>

Returns:

the total number of users

user2uidx

public int user2uidx(U u)

Description copied from interface: FastUserIndex

Returns the index assigned to the user.

Specified by:

user2uidx in interface FastUserIndex<U>

Parameters:

u - user

Returns:

the index of the user, or -1 if the user does not exist

uidx2user

public U uidx2user(int uidx)

Description copied from interface: FastUserIndex

Returns the user represented with the index.

Specified by:

uidx2user in interface FastUserIndex<U>

Parameters:

uidx - user index

Returns:

the user whose index is uidx

numItems

public int numItems()

Description copied from interface: ItemIndex

Counts the number of indexed items.

Specified by:

numItems in interface ItemIndex<I>

Returns:

the total number of item

item2iidx

public int item2iidx(I i)

Description copied from interface: FastItemIndex

Returns the index assigned to the item.

Specified by:

item2iidx in interface FastItemIndex<I>

Parameters:

i - item

Returns:

the index of the item, or -1 if the item does not exist

iidx2item

public I iidx2item(int iidx)

Description copied from interface: FastItemIndex

Returns the item represented with the index.

Specified by:

iidx2item in interface FastItemIndex<I>

Parameters:

iidx - item index

Returns:

the item whose index is iidx

containsUser

public boolean containsUser(U u)

Description copied from interface: UserIndex

Checks whether the index contains a user.

Specified by:

containsUser in interface UserIndex<U>

Specified by:

containsUser in interface FastUserIndex<U>

Parameters:

u - user

Returns:

true if the index contains the user, false otherwise

containsItem

public boolean containsItem(I i)

Description copied from interface: ItemIndex

Checks whether the index contains an item.

Specified by:

containsItem in interface ItemIndex<I>

Specified by:

containsItem in interface FastItemIndex<I>

Parameters:

i - item

Returns:

true if the index contains the item, false otherwise

getUserVector

public cern.colt.matrix.DoubleMatrix1D getUserVector(U u)

Returns the row of the user matrix corresponding to the given user.

Parameters:

u - user

Returns:

row of the user matrix

getItemVector

public cern.colt.matrix.DoubleMatrix1D getItemVector(I i)

Returns the row of the item matrix corresponding to the given item.

Parameters:

i - item

Returns:

row of the item matrix

getUserMatrix

public cern.colt.matrix.impl.DenseDoubleMatrix2D getUserMatrix()

Returns the whole user matrix.

Returns:

the whole user matrix

getItemMatrix

public cern.colt.matrix.impl.DenseDoubleMatrix2D getItemMatrix()

Returns the whole item matrix.

Returns:

the whole item matrix

getK

public int getK()

Returns the dimension of the latent feature space.

Returns:

the dimension of the latent feature space