MyMediaLite  3.09
Public Member Functions | Properties
ItemRecommender Class Reference

Abstract item recommender class that loads the (positive-only implicit feedback) training data into memory and provides flexible access to it. More...

Inheritance diagram for ItemRecommender:
Recommender IRecommender BPRLinear ExternalItemRecommender IncrementalItemRecommender MostPopularByAttributes Random Zero KNN MF MostPopular SLIM ItemKNN UserKNN BPRMF WRMF BPRSLIM LeastSquareSLIM ItemAttributeKNN UserAttributeKNN MultiCoreBPRMF SoftMarginRankingMF WeightedBPRMF

List of all members.

Public Member Functions

virtual bool CanPredict (int user_id, int item_id)
 Check whether a useful prediction (i.e. not using a fallback/default answer) can be made for a given user-item combination.
Object Clone ()
 create a shallow copy of the object
virtual void LoadModel (string file)
 Get the model parameters from a file.
abstract float Predict (int user_id, int item_id)
 Predict rating or score for a given user-item combination.
IList< Tuple< int, float > > Recommend (int user_id, int n=-1, ICollection< int > ignore_items=null, ICollection< int > candidate_items=null)
 Recommend items for a given user.
virtual
System.Collections.Generic.IList
< Tuple< int, float > > 
Recommend (int user_id, int n=-1, System.Collections.Generic.ICollection< int > ignore_items=null, System.Collections.Generic.ICollection< int > candidate_items=null)
virtual void SaveModel (string file)
 Save the model parameters to a file.
override string ToString ()
 Return a string representation of the recommender.
abstract void Train ()
 Learn the model parameters of the recommender from the training data.

Properties

virtual IPosOnlyFeedback Feedback [get, set]
 the feedback data to be used for training
int MaxItemID [get, set]
 Maximum item ID.
int MaxUserID [get, set]
 Maximum user ID.

Detailed Description

Abstract item recommender class that loads the (positive-only implicit feedback) training data into memory and provides flexible access to it.

The data is stored in two sparse matrices: one user-wise (in the rows) and one item-wise.

Positive-only means we only which items a user has accessed/liked, but not which items a user does not like. If there is not data for a specific item, we do not know whether the user has just not yet accessed the item, or whether they really dislike it.

See http://recsyswiki/wiki/Item_recommendation and http://recsyswiki/wiki/Implicit_feedback


Member Function Documentation

virtual bool CanPredict ( int  user_id,
int  item_id 
) [inline, virtual, inherited]

Check whether a useful prediction (i.e. not using a fallback/default answer) can be made for a given user-item combination.

It is up to the recommender implementor to decide when a prediction is useful, and to document it accordingly.

Parameters:
user_idthe user ID
item_idthe item ID
Returns:
true if a useful prediction can be made, false otherwise

Implements IRecommender.

Reimplemented in ExternalItemRecommender, ExternalRatingPredictor, BiPolarSlopeOne, SlopeOne, Constant, GlobalAverage, UserAverage, ItemAverage, and Random.

Object Clone ( ) [inline, inherited]

create a shallow copy of the object

virtual void LoadModel ( string  filename) [inline, virtual, inherited]
abstract float Predict ( int  user_id,
int  item_id 
) [pure virtual, inherited]
IList<Tuple<int, float> > Recommend ( int  user_id,
int  n = -1,
ICollection< int >  ignore_items = null,
ICollection< int >  candidate_items = null 
) [inherited]

Recommend items for a given user.

Parameters:
user_idthe user ID
nthe number of items to recommend, -1 for as many as possible
ignore_itemscollection if items that should not be returned; if null, use empty collection
candidate_itemsthe candidate items to choose from; if null, use all items
Returns:
a sorted list of (item_id, score) tuples

Implemented in WeightedEnsemble, and Ensemble.

virtual void SaveModel ( string  filename) [inline, virtual, inherited]
override string ToString ( ) [inline, inherited]

Property Documentation

virtual IPosOnlyFeedback Feedback [get, set]

the feedback data to be used for training

int MaxItemID [get, set, inherited]

Maximum item ID.

int MaxUserID [get, set, inherited]

Maximum user ID.


The documentation for this class was generated from the following file: