empirical.java

一个用于排队系统仿真的开源软件,有非常形象的图象仿真过程!

/**    
  * Copyright (C) 2006, Laboratorio di Valutazione delle Prestazioni - Politecnico di Milano

  * 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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  */
  
package jmt.engine.random;

import jmt.common.exception.IncorrectDistributionParameterException;
import jmt.engine.random.engine.RandomEngine;


/**
 *
 * This is the Empirical distribution, which is constructed with
 * data provided by the user.
 *
 * <br><br>Copyright (c) 2003
 * <br>Politecnico di Milano - dipartimento di Elettronica e Informazione
 * @author Fabrizio Frontera - [e-mail]
 */

public class Empirical extends Distribution {

	/**
	 * This is the constructor. It creates a new empirical distribution.
	 */
	public Empirical() {
		engine = RandomEngine.makeDefault();
	}

	/**
	 *
	 * This method is used to evaluate the probability
     * distribution function (pdf) where required by the user.
	 *
	 * @param x double indicating where to evaluate the pdf.
	 * @param p parameter of the empirical distribution.
	 * @throws IncorrectDistributionParameterException
	 * @return double with the probability distribution function evaluated in x.
	 */

	public double pdf(double x, Parameter p)
	        throws IncorrectDistributionParameterException {
		if (p.check()) {

            int k = (int) x;
            double[] pdf = ((EmpiricalPar) p).getPDF();

            //OLD
            //return pdf[k];

            //TODO: l'approssimazione del casting