net.sf.jclal.activelearning.scenario.StreamBasedOnlineSelectiveSamplingScenario.java Source code

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Here is the source code for net.sf.jclal.activelearning.scenario.StreamBasedOnlineSelectiveSamplingScenario.java

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/*
 * This program 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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */
package net.sf.jclal.activelearning.scenario;

import java.util.ArrayList;
import java.util.List;
import net.sf.jclal.activelearning.batchmode.AbstractBatchMode;
import net.sf.jclal.activelearning.querystrategy.AbstractQueryStrategy;
import net.sf.jclal.activelearning.singlelabel.querystrategy.AbstractSingleLabelOnlineQueryStrategy;
import net.sf.jclal.util.sort.Container;
import org.apache.commons.configuration.Configuration;
import weka.core.Instance;
import weka.core.Instances;

/**
 * Implementation of Stream-Based Online Sampling scenario. This scenario is sometimes
 * called sequential active.
 *
 * @author Oscar Gabriel Reyes Pupo
 * @author Eduardo Perez Perdomo
 *
 */
public class StreamBasedOnlineSelectiveSamplingScenario extends AbstractScenario {

    private static final long serialVersionUID = 1L;
    /*
     * The threshold must be configured in dependence of the query strategy. For
     * example:
     * 
     * UncertaintySampling=0.5 DensityDiversity=0.7
     * EntropySamplingQueryStrategy=0.7 LeastConfidence=0.7 ErrorReduction=0.39
     * MarginSampling=0.7 RandomSampling=1 RelevanceSampling=0.7
     * 
     */
    private double threshold = 0.5;

    private double values[];

    /**
     * Get the threshold
     *
     * @return The threshold used when the scenario is stream.
     */
    public double getThreshold() {
        return threshold;
    }

    /**
     * 
     * Set the threshold
     * 
     * @param threshold
     *            The threshold used when the scenario is stream.
     *
     */
    public void setThreshold(double threshold) {
        this.threshold = threshold;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void instancesSelection() {

        // found values of all unlabeled instances
        //values = getQueryStrategy().testUnlabeledData();

        Instances unlabelled = getQueryStrategy().getUnlabelledData().getDataset();

        List<Container> selection = new ArrayList<Container>();

        for (int i = 0; i < unlabelled.numInstances(); i++) {

            //passed
            ((AbstractSingleLabelOnlineQueryStrategy) getQueryStrategy()).setNumPassedInstances(i + 1);

            Instance in = unlabelled.instance(i);

            double test = getQueryStrategy().utilityInstance(in);

            if (getQueryStrategy().isMaximal() && test >= threshold) {
                selection.add(new Container(test, i));
            } else if (!getQueryStrategy().isMaximal() && test <= threshold) {
                selection.add(new Container(test, i));
            }

            if (selection.size() == ((AbstractBatchMode) getBatchMode()).getBatchSize()) {
                break;
            }
        }

        ((AbstractQueryStrategy) getQueryStrategy()).getSelectedInstances()
                .addAll(getBatchMode().instancesSelection(getQueryStrategy(), selection));
    }

    /**
     *
     * @param configuration
     *            The configuration of Stream Scenario. The XML labels supported
     *            are:
     *            <ul>
     *            <li><b>threshold= double</b></li>
     *            </ul>
     */
    @Override
    public void configure(Configuration configuration) {

        super.configure(configuration);

        // Set threshold
        double thresholdT = configuration.getDouble("threshold", threshold);

        setThreshold(thresholdT);
    }
}