org.grouplens.lenskit.basic

Class AbstractGlobalItemRecommender

java.lang.Object

org.grouplens.lenskit.basic.AbstractGlobalItemRecommender

All Implemented Interfaces:

GlobalItemRecommender

Direct Known Subclasses:

TopNGlobalItemRecommender

public abstract class AbstractGlobalItemRecommender
extends Object
implements GlobalItemRecommender

Base class for item recommenders. It implements all methods required by GlobalItemRecommender by delegating them to general methods with fastutil-based interfaces.

Constructor Summary

Constructors

Constructor and Description
AbstractGlobalItemRecommender()

Method Summary

Modifier and Type	Method and Description
protected abstract List<ScoredId>	globalRecommend(LongSet items, int n, LongSet candidates, LongSet exclude) Implementation method for global item recommendation.
List<ScoredId>	globalRecommend(Set<Long> items) Recommend all possible items for a basket of items using the default exclude set.
List<ScoredId>	globalRecommend(Set<Long> items, int n) Recommend up to n items for a basket of items using the default exclude set.
List<ScoredId>	globalRecommend(Set<Long> items, int n, Set<Long> candidates, Set<Long> exclude) Produce a set of recommendations for the item.
List<ScoredId>	globalRecommend(Set<Long> items, Set<Long> candidates) Recommend all possible items for a basket of items from a set of candidates using the default exclude set.

Methods inherited from class java.lang.Object

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

Constructor Detail

AbstractGlobalItemRecommender

public AbstractGlobalItemRecommender()

Method Detail

globalRecommend

public List<ScoredId> globalRecommend(Set<Long> items)

Recommend all possible items for a basket of items using the default exclude set.

Delegates to globalRecommend(LongSet, int, LongSet, LongSet).

Specified by:

globalRecommend in interface GlobalItemRecommender

Parameters:

items - The items value.

Returns:

The recommended items.

See Also:

GlobalItemRecommender.globalRecommend(Set, int, Set, Set)

globalRecommend

public List<ScoredId> globalRecommend(Set<Long> items,
                                      int n)

Recommend up to n items for a basket of items using the default exclude set.

Delegates to globalRecommend(LongSet, int, LongSet, LongSet).

Specified by:

globalRecommend in interface GlobalItemRecommender

Parameters:

items - The items value.

n - The number of recommendations to return.

Returns:

The recommended items.

See Also:

GlobalItemRecommender.globalRecommend(Set, int, Set, Set)

globalRecommend

public List<ScoredId> globalRecommend(Set<Long> items,
                                      @Nullable
                                      Set<Long> candidates)

Recommend all possible items for a basket of items from a set of candidates using the default exclude set.

Delegates to globalRecommend(LongSet, int, LongSet, LongSet).

Specified by:

globalRecommend in interface GlobalItemRecommender

Parameters:

items - The items value.

candidates - The candidate set (can be null to represent the universe).

Returns:

The recommended items.

See Also:

GlobalItemRecommender.globalRecommend(Set, int, Set, Set)

globalRecommend

public List<ScoredId> globalRecommend(Set<Long> items,
                                      int n,
                                      @Nullable
                                      Set<Long> candidates,
                                      @Nullable
                                      Set<Long> exclude)

Produce a set of recommendations for the item. This is the most general recommendation method, allowing the recommendations to be constrained by both a candidate set and an exclude set. The exclude set is applied to the candidate set, so the final effective candidate set is candidates minus exclude.

Delegates to globalRecommend(LongSet, int, LongSet, LongSet).

Specified by:

globalRecommend in interface GlobalItemRecommender

Parameters:

items - The items value

n - The number of ratings to return. If negative, no specific size is requested.

candidates - A set of candidate items which can be recommended. If null, all items are considered candidates.

exclude - A set of items to be excluded. If null, a default exclude set is used.

Returns:

A list of recommended items. If the recommender cannot assign meaningful scores, the scores will be Double.NaN.

globalRecommend

protected abstract List<ScoredId> globalRecommend(LongSet items,
                                                  int n,
                                                  @Nullable
                                                  LongSet candidates,
                                                  @Nullable
                                                  LongSet exclude)

Implementation method for global item recommendation.

Parameters:

items - The items ID.

n - The number of items to return, or negative to return all possible items.

candidates - The candidate set.

exclude - The set of excluded items, or null to use the default exclude set.

Returns:

A scored list of item IDs.

See Also:

GlobalItemRecommender.globalRecommend(Set, int, Set, Set)