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java.lang.Objectorg.mymedialite.ratingprediction.RatingPredictor
org.mymedialite.ratingprediction.TimeAwareRatingPredictor
org.mymedialite.ratingprediction.TimeAwareBaseline
org.mymedialite.ratingprediction.TimeAwareBaselineWithFrequencies
public class TimeAwareBaselineWithFrequencies
Time-aware bias model with frequencies. Model described in equation (11) of BellKor Grand Prize documentation for the Netflix Prize (see below). The default hyper-parameter values are set to the ones shown in the report. For datasets other than Netflix, you may want to find better parameters. Literature: Yehuda Koren: The BellKor Solution to the Netflix Grand Prize This recommender does currently NOT support incremental updates.
Field Summary | |
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double |
FrequencyLogBase
logarithmic base for the frequency counts. |
double |
ItemBiasAtFrequencyLearnRate
Learn rate for b_{i, f_{ui}}. |
double |
RegItemBiasAtFrequency
Regularization constant for b_{i, f_{ui}}. |
Fields inherited from class org.mymedialite.ratingprediction.TimeAwareBaseline |
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alphaLearnRate, beta, binSize, itemBiasByTimeBinLearnRate, itemBiasLearnRate, numIter, regAlpha, regI, regItemBiasByTimeBin, regU, regUserBiasByDay, regUserScaling, regUserScalingByDay, userBiasByDayLearnRate, userBiasLearnRate, userScalingByDayLearnRate, userScalingLearnRate |
Fields inherited from class org.mymedialite.ratingprediction.TimeAwareRatingPredictor |
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timed_ratings |
Fields inherited from class org.mymedialite.ratingprediction.RatingPredictor |
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maxItemID, maxRating, maxUserID, minRating, ratings |
Constructor Summary | |
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TimeAwareBaselineWithFrequencies()
Default constructor. |
Method Summary | |
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double |
computeLoss()
Compute the current loss of the model |
protected void |
initModel()
Initialize the model parameters. |
double |
predict(int user_id,
int item_id,
java.util.Date time)
predict rating at a certain point in time. |
protected double |
predict(int user_id,
int item_id,
int day,
int bin)
Predict the specified user_id, item_id, day and bin. |
java.lang.String |
toString()
Return a string representation of the recommender |
void |
train()
Learn the model parameters of the recommender from the training data |
protected void |
updateParameters(int u,
int i,
int day,
int bin,
double err)
Single SGD step: update the parameter values for one user and one item. |
Methods inherited from class org.mymedialite.ratingprediction.TimeAwareBaseline |
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getNumIter, iterate, loadModel, predict, relativeDay, saveModel, setNumIter |
Methods inherited from class org.mymedialite.ratingprediction.TimeAwareRatingPredictor |
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getRatings, getTimedRatings, setRatings, setTimedRatings |
Methods inherited from class org.mymedialite.ratingprediction.RatingPredictor |
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canPredict, clone, getMaxRating, getMinRating, setMaxRating, setMinRating |
Methods inherited from class java.lang.Object |
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equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait |
Methods inherited from interface org.mymedialite.ratingprediction.IRatingPredictor |
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getMaxRating, getMinRating, setMaxRating, setMinRating |
Methods inherited from interface org.mymedialite.IRecommender |
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canPredict |
Field Detail |
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public double FrequencyLogBase
public double RegItemBiasAtFrequency
public double ItemBiasAtFrequencyLearnRate
Constructor Detail |
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public TimeAwareBaselineWithFrequencies()
Method Detail |
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public void train()
IRecommender
train
in interface IRecommender
train
in class TimeAwareBaseline
protected void initModel()
TimeAwareBaseline
initModel
in class TimeAwareBaseline
protected void updateParameters(int u, int i, int day, int bin, double err)
TimeAwareBaseline
updateParameters
in class TimeAwareBaseline
protected double predict(int user_id, int item_id, int day, int bin)
TimeAwareBaseline
predict
in class TimeAwareBaseline
public double predict(int user_id, int item_id, java.util.Date time)
ITimeAwareRatingPredictor
predict
in interface ITimeAwareRatingPredictor
predict
in class TimeAwareBaseline
user_id
- the user IDitem_id
- the item IDtime
- the time of the rating event
public double computeLoss()
IIterativeModel
computeLoss
in interface IIterativeModel
computeLoss
in class TimeAwareBaseline
public java.lang.String toString()
IRecommender
toString
in interface IRecommender
toString
in class TimeAwareBaseline
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