net.librec.recommender.ext

Class ExternalRecommender

java.lang.Object

net.librec.recommender.AbstractRecommender

net.librec.recommender.ext.ExternalRecommender

All Implemented Interfaces:

Recommender

@ModelData(value={"isRating","external","trainMatrix"})
public class ExternalRecommender
extends AbstractRecommender

Suppose that you have some predictive ratings (in "pred.txt") generated by an external recommender (e.g., some recommender of MyMediaLite). The predictions are in the format of user-item-prediction. These predictions are corresponding to a test set "test.txt" (user-item-held_out_rating). This class (ExternalRecommender) provides you with the ability to compute predictive performance by setting the training set as "pred.txt" and the test set as "test.txt".

NOTE: This approach is not applicable to item recommendation. Thank Marcel Ackermann for bringing this demand to my attention.

Author:

Guo Guibing and Keqiang Wang

Field Summary

Fields inherited from class net.librec.recommender.AbstractRecommender

conf, context, decay, earlyStop, globalMean, isBoldDriver, isRanking, itemMappingData, lastLoss, LOG, loss, maxRate, minRate, numItems, numRates, numUsers, ratingScale, recommendedList, testMatrix, topN, trainMatrix, userMappingData, validMatrix, verbose

Constructor Summary

Constructors

Constructor and Description
ExternalRecommender()

Method Summary

Methods

Modifier and Type	Method and Description
protected double	predict(int userIdx, int itemIdx) predict a specific rating for user userIdx on item itemIdx.
protected void	trainModel() train Model

Methods inherited from class net.librec.recommender.AbstractRecommender

cleanup, evaluate, evaluateMap, getContext, getDataModel, getRecommendedList, isConverged, loadModel, predict, recommend, recommend, recommendRank, recommendRating, saveModel, setContext, setup

Methods inherited from class java.lang.Object

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

Constructor Detail

ExternalRecommender

public ExternalRecommender()

Method Detail

trainModel

protected void trainModel()
                   throws LibrecException

Description copied from class: AbstractRecommender

train Model

Specified by:

trainModel in class AbstractRecommender

Throws:

LibrecException - if error occurs during training model

predict

protected double predict(int userIdx,
             int itemIdx)
                  throws LibrecException

predict a specific rating for user userIdx on item itemIdx.

Specified by:

predict in class AbstractRecommender

Parameters:

userIdx - user index

itemIdx - item index

Returns:

predictive rating for user userIdx on item itemIdx

Throws:

LibrecException - if error occurs