randomgenerator.java

著名的开源仿真软件yale

/*
 *  YALE - Yet Another Learning Environment
 *  Copyright (C) 2002, 2003
 *      Simon Fischer, Ralf Klinkenberg, Ingo Mierswa, 
 *          Katharina Morik, Oliver Ritthoff
 *      Artificial Intelligence Unit
 *      Computer Science Department
 *      University of Dortmund
 *      44221 Dortmund,  Germany
 *  email: [e-mail]
 *  web:   http://yale.cs.uni-dortmund.de/
 *
 *  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., 59 Temple Place, Suite 330, Boston, MA 02111-1307
 *  USA.
 */
package edu.udo.cs.yale.tools;


import edu.udo.cs.yale.Yale;
import edu.udo.cs.yale.Experiment;
import edu.udo.cs.yale.tools.ParameterService;

import java.util.Random;

/** The global random number generator.
 *
 *  @author ralf, ingo
 *  @version $Id: RandomGenerator.java,v 2.2 2003/07/24 15:40:59 fischer Exp $
 */

public class  RandomGenerator extends Random {
    /** global random number generator using the random number generator seed specified
     *  in the <code>global</code> section of the configuration file.
     */
    public static RandomGenerator  globalRandomGenerator;

    /** initializes the random number generator with the given <code>seed</seed> */
    public  RandomGenerator(long seed) {
	super(seed);
    }

    /** instantiates the global random number generator and initializes it with the 
     *  random number generator seed specified in the <code>global</code> section of
     *  the configuration file.
     */
    public static void  init(Experiment experiment) {
	long seed = experiment.getRootOperator().getParameterAsInt("random_seed");
	globalRandomGenerator = new RandomGenerator(seed);
    }

    /** returns the global random number generator. */
    public static RandomGenerator  getGlobalRandomGenerator() {  return globalRandomGenerator;  }


    /** returns the next pseudorandom, uniformly distributed <code>double</code> value between 
     *  <code>lowerBound</code> and <code>upperBound</code> from this random number
     *  generator's sequence (exclusive of the interval endpoint values).
     */
    public double  randomDoubleInRange (double lowerBound, double upperBound) {
	if (upperBound <= lowerBound) {
	    throw new IllegalArgumentException("RandomGenerator.randomDoubleInRange : the upper bound of the " +
					       "random number range should be greater than the lower bound.");
	}
	return ((nextDouble() * (upperBound - lowerBound)) + lowerBound);
    }

    /** returns the next pseudorandom, uniformly distributed <code>double</code> value between 
     *  <code>lowerBound</code> and <code>upperBound</code> from the global random
     *   number generator's sequence (exclusive of the interval endpoint values).
     */
    public static double  getRandomDoubleInRange (double lowerBound, double upperBound) {
	return globalRandomGenerator.randomDoubleInRange (lowerBound, upperBound);
    }


    /** returns the next pseudorandom, uniformly distributed <code>long</code> value between 
     *  <code>lowerBound</code> and <code>upperBound</code> from this random number
     *  generator's sequence (exclusive of the interval endpoint values).
     */
    public long  randomLongInRange (long lowerBound, long upperBound) {
	if (upperBound <= lowerBound) {
	    throw new IllegalArgumentException("RandomGenerator.randomLongInRange : the upper bound of the " +
					       "random number range should be greater than the lower bound.");
	}
	return ((long)(nextDouble() * ((double)(upperBound - lowerBound + 1))) + lowerBound);
    }

    /** returns the next pseudorandom, uniformly distributed <code>long</code> value between 
     *  <code>lowerBound</code> and <code>upperBound</code> from the global random
     *   number generator's sequence (exclusive of the interval endpoint values).
     */
    public static long  getRandomLongInRange (long lowerBound, long upperBound) {
	return globalRandomGenerator.randomLongInRange (lowerBound, upperBound);
    }


    /** returns the next pseudorandom, uniformly distributed <code>int</code> value between 
     *  <code>lowerBound</code> and <code>upperBound</code> from this random number
     *  generator's sequence (exclusive of the interval endpoint values).
     */
    public int  randomIntInRange (int lowerBound, int upperBound) {
	if (upperBound <= lowerBound) {
	    throw new IllegalArgumentException("RandomGenerator.randomIntInRange : the upper bound of the " +
					       "random number range should be greater than the lower bound.");
	}
	return ((int)(nextDouble() * ((double)(upperBound - lowerBound + 1))) + lowerBound);
    }

    /** returns the next pseudorandom, uniformly distributed <code>int</code> value between 
     *  <code>lowerBound</code> and <code>upperBound</code> from the global random
     *   number generator's sequence (exclusive of the interval endpoint values).
     */
    public static int  getRandomIntInRange (int lowerBound, int upperBound) {
	return globalRandomGenerator.randomIntInRange (lowerBound, upperBound);
    }

}