gridsimrandom.java

一个非常著名的网格模拟器,能够运行网格调度算法!

/*
 * Title:        GridSim Toolkit
 * Description:  GridSim (Grid Simulation) Toolkit for Modeling and Simulation
 *               of Parallel and Distributed Systems such as Clusters and Grids
 * Licence:      GPL - http://www.gnu.org/copyleft/gpl.html
 *
 * $Id: GridSimRandom.java,v 1.13 2004/11/01 02:52:35 anthony Exp $
 */

package gridsim;

import java.util.Random;

/**
 * GridSim Random provides static methods for incorporating randomness in data
 * used for any simulation.
 * <p>
 * This class will be created by GridSim upon initialization of the simulation,
 * i.e. done via <tt>GridSim.init()</tt> method. Hence, do not need to worry
 * about creating an object of this class.
 * <p>
 * Any predicted or estimated data, e.g. number of
 * Gridlets used by an experiment, execution time and output size of a Gridlet,
 * etc. need to present in the prediction or estimation process and the
 * randomness that exists in the nature itself.
 * <p>
 * <tt>Example:</tt> to produce a random number between 18.00 and 22.00, need
 * to invoke <tt>GridSimRandom.real(20.0, 0.1, 0.1, randDouble)</tt> where
 * <tt>randDouble</tt> comes from <b>java.util.Random</b>.
 *
 * @author       Manzur Murshed and Rajkumar Buyya
 * @since        GridSim Toolkit 1.0
 * @see gridsim.Gridlet
 * @see java.util.Random
 * @invariant $none
 * @see gridsim.GridSim#init(int, Calendar, boolean)
 * @see gridsim.GridSim#init(int, Calendar, boolean, String[], String[], String)
 */
public class GridSimRandom
{
    private static final int MIN_VALUE = 0;
    private static final int MAX_VALUE = 1;
    private static Random random_;

    // Factor values for Network I/O
    private static double lessFactorIO_;
    private static double moreFactorIO_;

    // Factor values for Execution
    private static double lessFactorExec_;
    private static double moreFactorExec_;

    /** Initializes all static variables */
    static
    {
        random_ = new Random();
        lessFactorIO_ = 0.0;
        moreFactorIO_ = 0.0;
        lessFactorExec_ = 0.0;
        moreFactorExec_ = 0.0;
    }

    /**
     * Allocates a new GridSimRandom object
     * @pre $none
     * @post $none
     */
    public GridSimRandom() {
        // empty
    }

    /**
     * Allocates a new GridSimRandom object using a single <tt>long</tt> seed
     * @param seed the initial seed
     * @pre seed >= 0.0
     * @post $none
     */
    public GridSimRandom(long seed) {
        random_.setSeed(seed);
    }

    /**
     * Allocates a new GridSimRandom object with specified parameters
     * @param seed          the initial seed
     * @param lessFactorIO  less factor for Network I/O
     * @param moreFactorIO  more factor for Network I/O
     * @param lessFactorExec   less factor for execution
     * @param moreFactorExec   more factor for execution
     * @pre seed >= 0.0
     * @pre lessFactorIO >= 0.0
     * @pre moreFactorIO >= 0.0
     * @pre lessFactorExec >= 0.0
     * @pre moreFactorExec >= 0.0
     * @post $none
     */
    public GridSimRandom(long seed, double lessFactorIO, double moreFactorIO,
                double lessFactorExec, double moreFactorExec)
    {
        random_.setSeed(seed);
        lessFactorIO_ = lessFactorIO;
        moreFactorIO_ = moreFactorIO;
        lessFactorExec_ = lessFactorExec;
        moreFactorExec_ = moreFactorExec;
    }

    /**
     * Sets the Network I/O and execution values
     * @param lessFactorIOValue  less factor for Network I/O
     * @param moreFactorIOValue  more factor for Network I/O
     * @param lessFactorExecValue   less factor for execution
     * @param moreFactorExecValue   more factor for execution
     * @deprecated As of GridSim 2.1, replaced by {@link #setAllFactors(double,
     *             double, double, double)}
     * @pre lessFactorIOValue >= 0.0
     * @pre moreFactorIOValue >= 0.0
     * @pre lessFactorExecValue >= 0.0
     * @pre moreFactorExecValue >= 0.0
     * @post $none
     */
    public static void set_factors(double lessFactorIOValue,
                double moreFactorIOValue, double lessFactorExecValue,
                double moreFactorExecValue)
    {
        setAllFactors(lessFactorIOValue, moreFactorIOValue, lessFactorExecValue,
                moreFactorExecValue);
    }

    /**
     * Sets the Network I/O and execution values
     * @param lessFactorIOValue  less factor for Network I/O
     * @param moreFactorIOValue  more factor for Network I/O
     * @param lessFactorExecValue   less factor for execution
     * @param moreFactorExecValue   more factor for execution
     * @pre lessFactorIOValue >= 0.0
     * @pre moreFactorIOValue >= 0.0
     * @pre lessFactorExecValue >= 0.0
     * @pre moreFactorExecValue >= 0.0
     * @post $none
     */
    public static void setAllFactors(double lessFactorIOValue,
                double moreFactorIOValue, double lessFactorExecValue,
                double moreFactorExecValue)
    {
        lessFactorIO_ = lessFactorIOValue;
        moreFactorIO_ = moreFactorIOValue;
        lessFactorExec_ = lessFactorExecValue;
        moreFactorExec_ = moreFactorExecValue;
    }

    /**
     * Gets the random int value from <b>java.util.Random</b>
     * @param range the bound on the random number to be returned.
     *              The range must be positive (excluding 0).
     * @return a pseudorandom, uniformly distributed <tt>int</tt> value between
     *         0 (inclusive) and range (exclusive)
     * @throws IllegalArgumentException range is not positive
     * @deprecated As of GridSim 2.1, replaced by {@link #intSample(int)}
     * @pre range > 0
     * @post $result >= 0
     */
    public static int int_sample(int range) throws IllegalArgumentException {
        return intSample(range);
    }

    /**
     * Gets the random int value from <b>java.util.Random</b>
     * @param range the bound on the random number to be returned.
     *              The range must be positive (excluding 0).
     * @return a pseudorandom, uniformly distributed <tt>int</tt> value between
     *         0 (inclusive) and range (exclusive)
     * @throws IllegalArgumentException range is not positive
     * @pre range > 0
     * @post $result >= 0
     */
    public static int intSample(int range) throws IllegalArgumentException {
        return random_.nextInt(range);
    }

    /**
     * Gets the random double value from <b>java.util.Random</b>
     * @return the next pseudorandom, uniformly distributed <tt>double</tt>
     *         value between 0.0 and 1.0 from this random number generator's
     *         sequence
     * @deprecated As of GridSim 2.1, replaced by {@link #doubleSample()}
     * @pre $none
     * @post $result >= 0.0 && $result <= 1.0
     */
    public static double double_sample() {
        return doubleSample();
    }

    /**
     * Gets the random double value from <b>java.util.Random</b>
     * @return the next pseudorandom, uniformly distributed <tt>double</tt>
     *         value between 0.0 and 1.0 from this random number generator's
     *         sequence
     * @pre $none
     * @post $result >= 0.0 && $result <= 1.0
     */
    public static double doubleSample() {
        return random_.nextDouble();
    }

    /**
     * Sets the less factor of Network I/O. If <tt>factor</tt> is less than
     * 0, then it is being ignored.
     * @param factor the initial factor
     * @throws IllegalArgumentException factor is not zero or positive
     * @deprecated As of GridSim 2.1, replaced by
     *             {@link #setLessFactorIO(double)}
     * @pre factor >= 0.0
     * @post $none
     */
    public static void set_less_factor_io(double factor)
                throws IllegalArgumentException
    {
        setLessFactorIO(factor);
    }

    /**
     * Sets the less factor of Network I/O
     * @param factor the initial factor
     * @throws IllegalArgumentException factor is not zero or positive
     * @pre factor >= 0.0
     * @post $none
     */
    public static void setLessFactorIO(double factor)
                throws IllegalArgumentException
    {
        if (factor < MIN_VALUE)
        {
            throw new IllegalArgumentException(
                    "GridSimRandom.setLessFactorIO() : Error - factor must" +
                    " be zero or positive value.");
        }
        lessFactorIO_ = factor;
    }

    /**
     * Sets the more factor of Network I/O
     * @param factor the initial factor
     * @throws IllegalArgumentException factor is not zero or positive
     * @deprecated As of GridSim 2.1, replaced by
     *             {@link #setMoreFactorIO(double)}
     * @pre factor >= 0.0
     * @post $none
     */
    public static void set_more_factor_io(double factor)
                throws IllegalArgumentException
    {
        setMoreFactorIO(factor);
    }

    /**
     * Sets the more factor of Network I/O
     * @param factor the initial factor
     * @throws IllegalArgumentException factor is not zero or positive
     * @pre factor >= 0.0
     * @post $none
     */
    public static void setMoreFactorIO(double factor)
                throws IllegalArgumentException
    {
        if (factor < MIN_VALUE)
        {
            throw new IllegalArgumentException(
                    "GridSimRandom.setMoreFactorIO() : Error - factor must" +
                    " be zero or positive value.");
        }
        moreFactorIO_ = factor;
    }

    /**
     * Sets the less factor of Execution
     * @param factor the initial factor
     * @throws IllegalArgumentException factor is not zero or positive
     * @deprecated As of GridSim 2.1, replaced by
     *             {@link #setLessFactorExec(double)}