fynche.util.SampleableKernelEstimator.java Source code

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Here is the source code for fynche.util.SampleableKernelEstimator.java

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/*
 * Fynche - a Framework for Multiagent Computational Creativity
 * Copyright 2011 Josh Hansen
 * 
 * This file is part of the Fynche <https://github.com/joshhansen/fynche>.
 * 
 * Fynche is free software: you can redistribute it and/or modify it
 * under the terms of the GNU Affero General Public License as published by the
 * Free Software Foundation, either version 3 of the License, or (at your
 * option) any later version.
 * 
 * Fynche 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 Affero General Public License
 * for more details.
 * 
 * You should have received a copy of the GNU Affero General Public License
 * along with Fynche.  If not, see <http://www.gnu.org/licenses/>.
 * 
 * If you have inquiries regarding any further use of Fynche, please
 * contact Josh Hansen <http://joshhansen.net/>
 */
package fynche.util;

import weka.estimators.KernelEstimator;

public class SampleableKernelEstimator extends KernelEstimator {
    private static final long serialVersionUID = 1L;

    public SampleableKernelEstimator(double precision) {
        super(precision);
    }

    public Double sample(final double min, final double max, final double stepSize) {
        final int binCount = (int) ((max - min) / stepSize);
        double totalProb = 0.0;
        double[] vals = new double[binCount];
        double[] probs = new double[binCount];
        int i = 0;
        for (double x = min; x < max; x += stepSize) {
            vals[i] = x;
            probs[i] = getProbability(x);
            totalProb += probs[i];
            i++;
        }

        final double position = Rand.nextDouble();
        double sum = 0.0;
        for (int j = 0; j < binCount; j++) {
            final double normedProb = probs[j] / totalProb;
            if (sum >= position || sum + normedProb >= 0.999999999)
                return vals[j];
            sum += normedProb;
        }
        return null;
    }

    public double getLogProbability(double data) {
        final double prob = super.getProbability(data);
        if (prob == 0)
            return 0.0;
        return Math.log(prob);
    }

}