de.tud.kom.p2psim.impl.util.stat.distributions.NormalDistribution.java Source code

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Here is the source code for de.tud.kom.p2psim.impl.util.stat.distributions.NormalDistribution.java

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/*
 * Copyright (c) 2005-2011 KOM - Multimedia Communications Lab
 *
 * This file is part of PeerfactSim.KOM.
 * 
 * PeerfactSim.KOM 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 3 of the License, or
 * any later version.
 * 
 * PeerfactSim.KOM 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 PeerfactSim.KOM.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

package de.tud.kom.p2psim.impl.util.stat.distributions;

import org.apache.commons.math.MathException;
import org.apache.commons.math.distribution.NormalDistributionImpl;

import de.tud.kom.p2psim.impl.scenario.XMLConfigurableConstructor;
import de.tud.kom.p2psim.impl.simengine.Simulator;

/**
 *
 * @author <peerfact@kom.tu-darmstadt.de>
 * @version 05/06/2011
 *
 */
public class NormalDistribution implements Distribution {

    private NormalDistributionImpl normal;

    private double mu;

    private double sigma;

    @XMLConfigurableConstructor({ "mu", "sigma" })
    public NormalDistribution(double mu, double sigma) {
        this.mu = mu;
        this.sigma = sigma;
        normal = new NormalDistributionImpl(mu, sigma);
    }

    @Override
    public void writeBackToXML(BackWriter bw) {
        bw.writeSimpleType("mu", mu);
        bw.writeSimpleType("sigma", sigma);
    }

    @Override
    public double returnValue() {
        double random = Simulator.getRandom().nextDouble();
        double result;

        try {
            result = normal.inverseCumulativeProbability(random);
        } catch (MathException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            result = 0;
        }

        return result;
    }

    @Override
    public String toString() {
        return "NormalDistribution [mu=" + mu + ", sigma=" + sigma + "]";
    }

    /**
     * returns a random value normally distributed with mu = _mu and sigma =
     * _sigma.
     * 
     * @param _mu
     * @param _sigma
     * @return as double
     */
    public static double returnValue(double _mu, double _sigma) {
        try {
            NormalDistributionImpl d = new NormalDistributionImpl(_mu, _sigma);
            return d.inverseCumulativeProbability(Simulator.getRandom().nextDouble());
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            return 0;
        }

    }

}