Java tutorial
/* * 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.PoissonDistributionImpl; 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 PoissonDistribution implements Distribution { private double lambda; private PoissonDistributionImpl poisson; @XMLConfigurableConstructor({ "lambda" }) public PoissonDistribution(double lambda) { this.lambda = lambda; this.poisson = new PoissonDistributionImpl(lambda); } // returns the x-value for a random value in the cdf public double returnValue() { double random = Simulator.getRandom().nextDouble(); int result; try { result = poisson.inverseCumulativeProbability(random); } catch (MathException e) { // TODO Auto-generated catch block e.printStackTrace(); result = 0; } return result; } /** * returns a random value Poisson distributed with lamda = _lamda. * @param _lamda * @return as double */ public static double returnValue(double _lamda) { try { PoissonDistributionImpl d = new PoissonDistributionImpl(_lamda); return d.inverseCumulativeProbability(Simulator.getRandom().nextDouble()); } catch (MathException e) { // TODO Auto-generated catch block e.printStackTrace(); return 0; } } @Override public String toString() { return "PoissonDistribution [lambda=" + lambda + "]"; } @Override public void writeBackToXML(BackWriter bw) { bw.writeSimpleType("lambda", lambda); } }