/**
 * Copyright (c) 2011, The University of Southampton and the individual contributors.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
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 *      this list of conditions and the following disclaimer.
 *
 *   *  Redistributions in binary form must reproduce the above copyright notice,
 *      this list of conditions and the following disclaimer in the documentation
 *      and/or other materials provided with the distribution.
 *
 *   *  Neither the name of the University of Southampton nor the names of its
 *      contributors may be used to endorse or promote products derived from this
 *      software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
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package org.openimaj.experiment.evaluation.cluster.analyser;

import java.util.Map;

import org.openimaj.util.pair.IntIntPair;

/**
 * Create a measure of purity
 * @author Sina Samangooei (ss@ecs.soton.ac.uk)
 */
public class PurityClusterAnalyser implements ClusterAnalyser<PurityAnalysis>{

        @Override
        public PurityAnalysis analyse(int[][] correct, int[][] estimated) {
                Map<Integer,Integer> invCor = ClusterAnalyserUtils.invert(correct);
                Map<Integer,Integer> invEst = ClusterAnalyserUtils.invert(estimated);
                PurityAnalysis ret = new PurityAnalysis();
                double sumPurity = 0;
                for (int k = 0; k < estimated.length; k++) {
                        IntIntPair maxClassCount = ClusterAnalyserUtils.findMaxClassCount(estimated[k],invCor);
                        sumPurity+=maxClassCount.second;
                }
                ret.purity = sumPurity/invEst.size();
                return ret;
        }

        

}