prea.recommender.baseline
Class Constant

java.lang.Object
  extended by prea.recommender.baseline.BaselineRecommender
      extended by prea.recommender.baseline.Constant
All Implemented Interfaces:
Recommender

public class Constant
extends BaselineRecommender

The class implementing a baseline, always predicting with the given constant.

Since:
2012. 4. 20
Version:
1.1
Author:
Joonseok Lee

Field Summary
private  double constantValue
          The value which will be used for predicting all ratings.
 
Fields inherited from class prea.recommender.baseline.BaselineRecommender
itemCount, maxValue, minValue, rateMatrix, userCount
 
Constructor Summary
Constant(int uc, int ic, double max, double min, double val)
          Construct a constant model with the given data.
 
Method Summary
 double predict(int userId, int itemId)
          Predict a rating for the given user and item.
 
Methods inherited from class prea.recommender.baseline.BaselineRecommender
buildModel, evaluate
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

constantValue

private double constantValue
The value which will be used for predicting all ratings.

Constructor Detail

Constant

public Constant(int uc,
                int ic,
                double max,
                double min,
                double val)
Construct a constant model with the given data.

Parameters:
uc - The number of users in the dataset.
ic - The number of items in the dataset.
max - The maximum rating value in the dataset.
min - The minimum rating value in the dataset.
val - The target value which will be used as constant prediction.
Method Detail

predict

public double predict(int userId,
                      int itemId)
Predict a rating for the given user and item.

Specified by:
predict in class BaselineRecommender
Parameters:
userId - The target user.
itemId - The target item.
Returns:
predicted rating.