es.uam.eps.ir.ranksys.nn.item.neighborhood

Class ItemNeighborhood<I>

java.lang.Object

es.uam.eps.ir.ranksys.nn.item.neighborhood.ItemNeighborhood<I>

Type Parameters:

I - type of the items

All Implemented Interfaces:

ItemIndex<I>, FastItemIndex<I>, Neighborhood

Direct Known Subclasses:

CachedItemNeighborhood, InvertedItemNeighborhood, ThresholdItemNeighborhood, TopKItemNeighborhood

public abstract class ItemNeighborhood<I>
extends Object
implements Neighborhood, FastItemIndex<I>

Item neighborhood. Wraps a generic neighborhood and a fast item index.

Author:

Saúl Vargas (saul.vargas@uam.es)

Field Summary

Fields

Modifier and Type	Field and Description
protected FastItemIndex<I>	iIndex Fast item index.
protected Neighborhood	neighborhood Generic neighborhood.

Constructor Summary

Constructors

Constructor and Description
ItemNeighborhood(FastItemIndex<I> iIndex, Neighborhood neighborhood) Constructor.

Method Summary

Modifier and Type	Method and Description
Stream<Tuple2od<I>>	getNeighbors(I i) Returns a stream of item neighbors
Stream<Tuple2id>	getNeighbors(int idx) Returns the neighborhood of a user/index.
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.

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

containsItem, getAllIidx, getAllItems, iidx2item, iidx2item, item2iidx, item2iidx

Field Detail

iIndex

protected final FastItemIndex<I> iIndex

Fast item index.

neighborhood

protected final Neighborhood neighborhood

Generic neighborhood.

Constructor Detail

ItemNeighborhood

public ItemNeighborhood(FastItemIndex<I> iIndex,
                        Neighborhood neighborhood)

Constructor.

Parameters:

iIndex - fast item index

neighborhood - generic fast neighborhood

Method Detail

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

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

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

getNeighbors

public Stream<Tuple2id> getNeighbors(int idx)

Returns the neighborhood of a user/index.

Specified by:

getNeighbors in interface Neighborhood

Parameters:

idx - user/index whose neighborhood is calculated

Returns:

stream of user/item-similarity pairs.

getNeighbors

public Stream<Tuple2od<I>> getNeighbors(I i)

Returns a stream of item neighbors

Parameters:

i - item whose neighborhood is returned

Returns:

a stream of item-score pairs