data.statistics.MILStatistics.java Source code

Introduction

Here is the source code for data.statistics.MILStatistics.java

Source

/*
 *    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., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

package data.statistics;

import java.util.HashMap;
import weka.core.Instances;

/**
 * Class with methods to obtain information about a MIL dataset such as the
 * number of attributes per bag, the average number of instances per bag, and
 * the distribution of number of instances per bag...
 * 
 * @author F.J. Gonzalez
 * @author Eva Gigaja
 * @version 20150925
 */
public class MILStatistics {
    /** The minimum number of instances per bag. */
    int minInstancesPerBag;
    /** The maximum number of instances per bag. */
    int maxInstancesPerBag;
    /** The average number of instances per bag. */
    double avgInstancesPerBag;
    /** The number of attributes per bag. */
    int attributesPerBag;
    /** The number of bags. */
    int numBags;
    /** The distribution of number of instances per bag: */
    HashMap<Integer, Integer> distributionBags;

    /**
     * Calculates various MIML statistics, such as instancesPerBag and
     * attributesPerBag
     * 
     * @param dataSet
     *            A MIL dataset
     */
    public void calculateStats(Instances dataSet) {
        numBags = dataSet.numInstances();
        attributesPerBag = dataSet.instance(0).relationalValue(1).numAttributes();
        minInstancesPerBag = Integer.MAX_VALUE;
        maxInstancesPerBag = Integer.MIN_VALUE;

        // Each pair <Integer, Integer> stores <numberOfInstances, numberOfBags>
        distributionBags = new HashMap<Integer, Integer>();
        for (int i = 0; i < numBags; i++) {
            int nInstances = dataSet.instance(i).relationalValue(1).numInstances();
            if (nInstances < minInstancesPerBag) {
                minInstancesPerBag = nInstances;
            }
            if (nInstances > maxInstancesPerBag) {
                maxInstancesPerBag = nInstances;
            }
            if (distributionBags.containsKey(nInstances)) {
                distributionBags.put(nInstances, distributionBags.get(nInstances) + 1);
            } else {
                distributionBags.put(nInstances, 1);
            }
        }

        avgInstancesPerBag = 0.0;
        for (Integer set : distributionBags.keySet()) {
            avgInstancesPerBag += set * distributionBags.get(set);
        }
        avgInstancesPerBag = avgInstancesPerBag / numBags;
    }

    /**
     * Returns the average number of instances per bag.
     * 
     * @return instancesPerBag
     */
    public double getAvgInstancesPerBag() {
        return avgInstancesPerBag;
    }

    /**
     * Returns the number of attributes per bag.
     * 
     * @return attributesPerBag
     */
    public int getAttributesPerBag() {
        return attributesPerBag;
    }

    /**
     * Returns the number of bags.
     * 
     * @return numBags
     */
    public int getnumBags() {
        return numBags;
    }

    /**
     * Returns the distribution of number of instances per bags.
     * 
     * @return distributionBags
     */
    public HashMap<Integer, Integer> getDistributionBags() {
        return distributionBags;
    }

    /**
     * Returns distributionBags in textual representation.
     * 
     * @return string
     */
    protected String distributionBagsToString() {
        StringBuilder sb = new StringBuilder();
        for (Integer set : distributionBags.keySet()) {
            sb.append("\n\t<" + distributionBags.get(set) + "," + set + ">");
        }
        return (sb.toString());
    }

    /**
     * Returns distributionBags in CSV representation.
     * 
     * @return string
     */
    protected String distributionBagsToCSV() {
        StringBuilder sb = new StringBuilder();
        for (Integer set : distributionBags.keySet()) {
            sb.append("\n" + distributionBags.get(set) + ";" + set);
        }
        return (sb.toString());
    }

    /**
     * Returns statistics in textual representation.
     * 
     * @return string
     */
    public String toString() {
        StringBuilder sb = new StringBuilder();
        sb.append("\n----------------------------");
        sb.append("\nMIL Statistics--------------");
        sb.append("\n----------------------------");
        sb.append("\nnBags: " + numBags);
        sb.append("\nAvgInstancesPerBag: " + avgInstancesPerBag);
        sb.append("\nMinInstancesPerBag: " + minInstancesPerBag);
        sb.append("\nMaxInstancesPerBag: " + maxInstancesPerBag);
        sb.append("\nAttributesPerBag: " + attributesPerBag);
        sb.append("\nDistribution of bags <nBags, nInstances>:");
        sb.append(distributionBagsToString());
        return (sb.toString());
    }

    /**
     * Returns statistics in CSV representation.
     * 
     * @return string
     */
    public String toCSV() {
        StringBuilder sb = new StringBuilder();
        sb.append("\nMIL STATISTICS:");
        sb.append("\nnBags;" + numBags);
        sb.append("\nAvgInstancesPerBag;" + avgInstancesPerBag);
        sb.append("\nMinInstancesPerBag;" + minInstancesPerBag);
        sb.append("\nMaxInstancesPerBag;" + maxInstancesPerBag);
        sb.append("\nAttributesPerBag;" + attributesPerBag);
        sb.append("\nDistribution of bags <nBags, nInstances>");
        sb.append(distributionBagsToCSV());
        return (sb.toString());
    }

    /**
     * Returns the minimum number of instances per bag.
     * 
     * @return minInstancesPerBag
     */
    public int getMinInstancesPerBag() {
        return minInstancesPerBag;
    }

    /**
     * Returns the maximum number of instances per bag.
     * 
     * @return maxInstancesPerBag
     */
    public int getMaxInstancesPerBag() {
        return maxInstancesPerBag;
    }
}