ch.epfl.lsir.xin.algorithm.baseline.GlobalAverage.java Source code

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Here is the source code for ch.epfl.lsir.xin.algorithm.baseline.GlobalAverage.java

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//Copyright (C) 2014  Xin Liu
//
//RecMe: a lightweight recommendation algorithm library
//
//RecMe is free software; you can redistribute it and/or
//modify it under the terms of the GNU General Public License
//as published by the Free Software Foundation; either version 2
//of the License, or (at your option) any later version.
//
//This program is distributed in the hope that it will be useful,
//but WITHOUT ANY WARRANTY; without even the implied warranty of
//MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//GNU General Public License for more details.
//
//You should have received a copy of the GNU General Public License
//along with this program; if not, write to the Free Software
//Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

package ch.epfl.lsir.xin.algorithm.baseline;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;

import org.apache.commons.configuration.ConfigurationException;
import org.apache.commons.configuration.PropertiesConfiguration;
import org.apache.log4j.Logger;

import ch.epfl.lsir.xin.algorithm.IAlgorithm;
import ch.epfl.lsir.xin.datatype.RatingMatrix;
import ch.epfl.lsir.xin.model.NumericRating;

public class GlobalAverage implements IAlgorithm {

    /**
     * the rating matrix
     * */
    private RatingMatrix ratingMatrix = null;

    /**
     * logger of the system
     * */
    private PrintWriter logger = null;

    /**
     * Configuration file for parameter setting.
     * */
    private PropertiesConfiguration config = new PropertiesConfiguration();

    /**
     * mean
     * */
    private double mean = Double.NaN;

    /**
     * constructor
     * @param: training ratings
     * */
    public GlobalAverage(RatingMatrix ratingMatrix) {
        //set configuration file for parameter setting.
        config.setFile(new File(".//conf//GlobalMean.properties"));
        try {
            config.load();
        } catch (ConfigurationException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        this.ratingMatrix = ratingMatrix;
    }

    /**
     * constructor
     * @param: training ratings
     * @param: read a saved model or not
     * @param: file of a saved model 
     * */
    public GlobalAverage(RatingMatrix ratingMatrix, boolean readModel, String file) {
        //set configuration file for parameter setting.
        config.setFile(new File(".//conf//GlobalMean.properties"));
        try {
            config.load();
        } catch (ConfigurationException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        this.ratingMatrix = ratingMatrix;
        if (readModel)//read model from a local file
        {
            readModel(file);
        }
    }

    /**
     * This function predicts the rating from a user to an item
     * @param: id of the user
     * @param: id of the item
     * */
    public double predict(String userID, String itemID) {
        return this.mean;
    }

    /**
     * This function predicts the rating from a user to an item
     * @param: index of the user
     * @param: index of the item
     * */
    public double predict(int userIndex, int itemIndex) {
        return this.mean;
    }

    @Override
    public void saveModel(String file) {
        // TODO Auto-generated method stub
        try {
            PrintWriter printer = new PrintWriter(file);
            printer.println(this.mean);
            printer.flush();
            printer.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    @Override
    public void readModel(String file) {
        // TODO Auto-generated method stub
        logger.append("Read an existing model from a local file: " + file.toString() + "\n");
        try {
            BufferedReader reader = new BufferedReader(new FileReader(file));
            String line = null;
            while ((line = reader.readLine()) != null) {
                this.mean = Double.parseDouble(line.trim());
            }
            reader.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    @Override
    public void build() {
        // TODO Auto-generated method stub
        this.ratingMatrix.calculateGlobalAverage();
        this.mean = this.ratingMatrix.getAverageRating();
    }

    /**
     * @return the mean
     */
    public double getMean() {
        return mean;
    }

    /**
     * @param mean the mean to set
     */
    public void setMean(double mean) {
        this.mean = mean;
    }

    /**
     * @return the logger
     */
    public PrintWriter getLogger() {
        return logger;
    }

    /**
     * @param logger the logger to set
     */
    public void setLogger(PrintWriter logger) {
        this.logger = logger;
    }

}