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

Class SetSimilarity

java.lang.Object

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

All Implemented Interfaces:

Similarity

Direct Known Subclasses:

SetCosineSimilarity, SetJaccardSimilarity

public abstract class SetSimilarity
extends Object
implements Similarity

Set similarity. Based on the intersection of item/user profiles as sets.

Author:

Saúl Vargas (saul.vargas@uam.es)

Field Summary

Fields

Modifier and Type	Field and Description
protected FastPreferenceData<?,?>	data User-item preferences.
protected boolean	dense If true dense vectors are used to calculate similarities.

Constructor Summary

Constructors

Constructor and Description
SetSimilarity(FastPreferenceData<?,?> data, boolean dense) Constructor.

Method Summary

Modifier and Type	Method and Description
protected abstract double	sim(int intersectionSize, int na, int nb) Calculates the similarity value.
Stream<Tuple2id>	similarElems(int idx1) 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.

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.nn.sim.Similarity

similarity

Field Detail

data

protected final FastPreferenceData<?,?> data

User-item preferences.

dense

protected final boolean dense

If true dense vectors are used to calculate similarities.

Constructor Detail

SetSimilarity

public SetSimilarity(FastPreferenceData<?,?> data,
                     boolean dense)

Constructor.

Parameters:

data - preference data

dense - true for array-based calculations, false to map-based

Method Detail

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

similarElems

public Stream<Tuple2id> similarElems(int idx1)

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:

idx1 - index of user/item

Returns:

stream of index-similarity pairs

sim

protected abstract double sim(int intersectionSize,
                              int na,
                              int nb)

Calculates the similarity value.

Parameters:

intersectionSize - size of the intersection of sets

na - size of the first set

nb - size of the second set

Returns:

similarity value