org.grouplens.lenskit

Interface GlobalItemRecommender

All Known Implementing Classes:

AbstractGlobalItemRecommender, TopNGlobalItemRecommender

public interface GlobalItemRecommender

The interface for recommendation based on the items only. The difference from ItemRecommender is that the input is only the item or list of items instead of user specific information. This interface can be used to provide a Find Similar Items / People Also Liked feature.

Since:

0.10

See Also:

ItemRecommender

Compatibility

Public

Method Summary

Modifier and Type	Method and Description
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.

Method Detail

globalRecommend

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

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

Parameters:

items - The items value.

Returns:

The recommended items.

See Also:

globalRecommend(Set, int, Set, Set)

globalRecommend

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

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

Parameters:

items - The items value.

n - The number of recommendations to return.

Returns:

The recommended items.

See Also:

globalRecommend(Set, int, Set, Set)

globalRecommend

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.

Parameters:

items - The items value.

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

Returns:

The recommended items.

See Also:

globalRecommend(Set, int, Set, Set)

globalRecommend

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.

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.