org.ranksys.compression.preferences

Class AbstractCODECPreferenceData<U,I,Cu,Ci>

java.lang.Object

es.uam.eps.ir.ranksys.fast.preference.AbstractFastPreferenceData<U,I>

org.ranksys.fast.preference.IteratorsAbstractFastPreferenceData<U,I>

org.ranksys.compression.preferences.AbstractCODECPreferenceData<U,I,Cu,Ci>

Type Parameters:

U - type of users

I - type of items

Cu - coding for user identifiers

Ci - coding for item identifiers

All Implemented Interfaces:

ItemIndex<I>, UserIndex<U>, PreferenceData<U,I>, FastItemIndex<I>, FastUserIndex<U>, FastPreferenceData<U,I>, Serializable

Direct Known Subclasses:

BinaryCODECPreferenceData, RatingCODECPreferenceData

public abstract class AbstractCODECPreferenceData<U,I,Cu,Ci>
extends IteratorsAbstractFastPreferenceData<U,I>
implements FastPreferenceData<U,I>

Abstract PreferenceData using compression.
If you use this code, please cite the following papers:

• Vargas, S., Macdonald, C., Ounis, I. (2015). Analysing Compression Techniques for In-Memory Collaborative Filtering. In Poster Proceedings of the 9th ACM Conference on Recommender Systems. http://ceur-ws.org/Vol-1441/recsys2015_poster2.pdf.
• Catena, M., Macdonald, C., Ounis, I. (2014). On Inverted Index Compression for Search Engine Efficiency. In ECIR (pp. 359–371). doi:10.1007/978-3-319-06028-6_30

The code that reproduces the results of the RecSys 2015 poster by Vargas et al. in a separated project: http://github.com/saulvargas/recsys2015
The search index compression technologies of the ECIR paper by Catena et al. is part of the Terrier IR Platform: http://terrier.org/docs/v4.0/compression.html.

Author:

Saúl Vargas (Saul.Vargas@glasgow.ac.uk)

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected CODEC<Ci>	i_codec CODEC for item preferences.
protected Ci[]	i_idxs list of users for items.
protected int[]	i_len lengths of item preferences lists.
protected CODEC<Cu>	u_codec CODEC for user preferences.
protected Cu[]	u_idxs lists of items for users.
protected int[]	u_len lengths of user preferences lists.

Fields inherited from class es.uam.eps.ir.ranksys.fast.preference.AbstractFastPreferenceData

ii, iPrefFun, ui, uPrefFun

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AbstractCODECPreferenceData(FastUserIndex<U> users, FastItemIndex<I> items, CODEC<Cu> u_codec, CODEC<Ci> i_codec) Constructor with default IdxPref to IdPref converters.
protected	AbstractCODECPreferenceData(FastUserIndex<U> users, FastItemIndex<I> items, CODEC<Cu> u_codec, CODEC<Ci> i_codec, Function<IdxPref,IdPref<I>> uPrefFun, Function<IdxPref,IdPref<U>> iPrefFun) Constructor with custom IdxPref to IdPref converters.

Method Summary

Modifier and Type	Method and Description
it.unimi.dsi.fastutil.ints.IntIterator	getIidxUidxs(int iidx) Returns the user idxs of the preferences for an item.
IntStream	getIidxWithPreferences() Returns a stream of item indexes for which users have preferences.
it.unimi.dsi.fastutil.ints.IntIterator	getUidxIidxs(int uidx) Returns the item idxs of the preferences of a user.
IntStream	getUidxWithPreferences() Returns a stream of user indexes who have preferences for items.
int	numItems(int uidx) Returns the number of items for which the user has preference for.
int	numPreferences() Returns the total number of preferences
int	numUsers(int iidx) Returns the number of users who have a preference for the item.

Methods inherited from class org.ranksys.fast.preference.IteratorsAbstractFastPreferenceData

getIidxPreferences, getPreferences, getUidxPreferences, useIteratorsPreferentially

Methods inherited from class es.uam.eps.ir.ranksys.fast.preference.AbstractFastPreferenceData

containsItem, containsUser, getAllItems, getAllUsers, getItemPreferences, getItemsWithPreferences, getUserPreferences, getUsersWithPreferences, iidx2item, item2iidx, numItems, numItems, numItemsWithPreferences, numUsers, numUsers, numUsersWithPreferences, uidx2user, user2uidx

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.preference.FastPreferenceData

getIidxPreferences, getIidxVs, getUidxPreferences, getUidxVs, useIteratorsPreferentially

Methods inherited from interface es.uam.eps.ir.ranksys.core.preference.PreferenceData

getItemPreferences, getItemsWithPreferences, getUserPreferences, getUsersWithPreferences, numItems, numItemsWithPreferences, numUsers, numUsersWithPreferences

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

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

Methods inherited from interface es.uam.eps.ir.ranksys.core.index.UserIndex

numUsers

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

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

Methods inherited from interface es.uam.eps.ir.ranksys.core.index.ItemIndex

numItems

Field Detail

u_codec

protected final CODEC<Cu> u_codec

CODEC for user preferences.

i_codec

protected final CODEC<Ci> i_codec

CODEC for item preferences.

u_idxs

protected final Cu[] u_idxs

lists of items for users.

u_len

protected final int[] u_len

lengths of user preferences lists.

i_idxs

protected final Ci[] i_idxs

list of users for items.

i_len

protected final int[] i_len

lengths of item preferences lists.

Constructor Detail

AbstractCODECPreferenceData

protected AbstractCODECPreferenceData(FastUserIndex<U> users,
                                      FastItemIndex<I> items,
                                      CODEC<Cu> u_codec,
                                      CODEC<Ci> i_codec)

Constructor with default IdxPref to IdPref converters.

Parameters:

users - user index

items - item index

u_codec - user preferences CODEC

i_codec - item preferences CODEC

AbstractCODECPreferenceData

protected AbstractCODECPreferenceData(FastUserIndex<U> users,
                                      FastItemIndex<I> items,
                                      CODEC<Cu> u_codec,
                                      CODEC<Ci> i_codec,
                                      Function<IdxPref,IdPref<I>> uPrefFun,
                                      Function<IdxPref,IdPref<U>> iPrefFun)

Constructor with custom IdxPref to IdPref converters.

Parameters:

users - user index

items - item index

u_codec - user preferences CODEC

i_codec - item preferences CODEC

uPrefFun - user IdxPref to IdPref converter

iPrefFun - item IdxPref to IdPref converter

Method Detail

numUsers

public int numUsers(int iidx)

Description copied from interface: FastPreferenceData

Returns the number of users who have a preference for the item.

Specified by:

numUsers in interface FastPreferenceData<U,I>

Parameters:

iidx - item index

Returns:

number of users who have a preference for the item

numItems

public int numItems(int uidx)

Description copied from interface: FastPreferenceData

Returns the number of items for which the user has preference for.

Specified by:

numItems in interface FastPreferenceData<U,I>

Parameters:

uidx - user index

Returns:

number of items for which the user has preference for

numPreferences

public int numPreferences()

Description copied from interface: PreferenceData

Returns the total number of preferences

Specified by:

numPreferences in interface PreferenceData<U,I>

Returns:

total number of preferences

getUidxWithPreferences

public IntStream getUidxWithPreferences()

Description copied from interface: FastPreferenceData

Returns a stream of user indexes who have preferences for items.

Specified by:

getUidxWithPreferences in interface FastPreferenceData<U,I>

Returns:

a stream of user indexes who have preferences for items

getIidxWithPreferences

public IntStream getIidxWithPreferences()

Description copied from interface: FastPreferenceData

Returns a stream of item indexes for which users have preferences.

Specified by:

getIidxWithPreferences in interface FastPreferenceData<U,I>

Returns:

a stream of item indexes for which users have preferences

getUidxIidxs

public it.unimi.dsi.fastutil.ints.IntIterator getUidxIidxs(int uidx)

Description copied from interface: FastPreferenceData

Returns the item idxs of the preferences of a user.

Specified by:

getUidxIidxs in interface FastPreferenceData<U,I>

Parameters:

uidx - user index

Returns:

iterator of the idxs of the items

getIidxUidxs

public it.unimi.dsi.fastutil.ints.IntIterator getIidxUidxs(int iidx)

Description copied from interface: FastPreferenceData

Returns the user idxs of the preferences for an item.

Specified by:

getIidxUidxs in interface FastPreferenceData<U,I>

Parameters:

iidx - item index

Returns:

iterator of the idxs of the users.