es.uam.eps.ir.ranksys.nn.user.sim

Class UserSimilarity<U>

java.lang.Object

es.uam.eps.ir.ranksys.nn.user.sim.UserSimilarity<U>

Type Parameters:

U - type of the users

All Implemented Interfaces:

UserIndex<U>, FastUserIndex<U>, Similarity

Direct Known Subclasses:

SetCosineUserSimilarity, SetJaccardUserSimilarity, VectorCosineUserSimilarity, VectorJaccardUserSimilarity

public abstract class UserSimilarity<U>
extends Object
implements Similarity, FastUserIndex<U>

User similarity. It wraps a generic fast similarity and a fast user index.

Author:

Saúl Vargas (saul.vargas@uam.es)

Field Summary

Fields

Modifier and Type	Field and Description
protected Similarity	sim Generic fast similarity.
protected FastUserIndex<U>	uIndex Fast user index.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	UserSimilarity(FastUserIndex<U> uIndex, Similarity sim) Constructor.

Method Summary

Modifier and Type	Method and Description
int	numUsers() Counts the number of indexed users.
Stream<Tuple2id>	similarElems(int idx) Returns all the users/items having a similarity greater than 0, together with the value of the similarity.
IntToDoubleFunction	similarity(int idx1) Returns a function that returns the similarity with the user/item.
double	similarity(int idx1, int idx2) Returns the similarity between two users/items.
ToDoubleFunction<U>	similarity(U u1) Returns a function returning similarities with the user
double	similarity(U u1, U u2) Returns the similarity between a pair of users.
Stream<Tuple2id>	similarUsers(int uidx) Returns all the users that are similar to the user - fast version.
Stream<Tuple2od<U>>	similarUsers(U u) Returns all the users that are similar to the user.
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.FastUserIndex

containsUser, getAllUidx, getAllUsers, uidx2user, uidx2user, user2uidx, user2uidx

Field Detail

uIndex

protected final FastUserIndex<U> uIndex

Fast user index.

sim

protected final Similarity sim

Generic fast similarity.

Constructor Detail

UserSimilarity

protected UserSimilarity(FastUserIndex<U> uIndex,
                         Similarity sim)

Constructor.

Parameters:

uIndex - fast user index

sim - generic fast similarity

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

similarity

public ToDoubleFunction<U> similarity(U u1)

Returns a function returning similarities with the user

Parameters:

u1 - user

Returns:

a function returning similarities with the user

similarity

public double similarity(U u1,
                         U u2)

Returns the similarity between a pair of users.

Parameters:

u1 - first user

u2 - second user

Returns:

similarity value between the users

similarUsers

public Stream<Tuple2od<U>> similarUsers(U u)

Returns all the users that are similar to the user.

Parameters:

u - user

Returns:

a stream of user-similarity pairs

similarUsers

public Stream<Tuple2id> similarUsers(int uidx)

Returns all the users that are similar to the user - fast version.

Parameters:

uidx - user

Returns:

a stream of user-similarity pairs

similarity

public IntToDoubleFunction similarity(int idx1)

Description copied from interface: Similarity

Returns a function that returns the similarity with the user/item.

Specified by:

similarity in interface Similarity

Parameters:

idx1 - index of the user/item

Returns:

function that returns the similarity with the index

similarity

public double similarity(int idx1,
                         int idx2)

Description copied from interface: Similarity

Returns the similarity between two users/items.

Specified by:

similarity in interface Similarity

Parameters:

idx1 - index of user/item

idx2 - index of user/item

Returns:

similarity between the pair

similarElems

public Stream<Tuple2id> similarElems(int idx)

Description copied from interface: Similarity

Returns all the users/items having a similarity greater than 0, together with the value of the similarity.

Specified by:

similarElems in interface Similarity

Parameters:

idx - index of user/item

Returns:

stream of index-similarity pairs