MonteCarlo.java

/*
 * ProActive Parallel Suite(TM):
 * The Open Source library for parallel and distributed
 * Workflows & Scheduling, Orchestration, Cloud Automation
 * and Big Data Analysis on Enterprise Grids & Clouds.
 *
 * Copyright (c) 2007 - 2017 ActiveEon
 * Contact: contact@activeeon.com
 *
 * This library is free software: you can redistribute it and/or
 * modify it under the terms of the GNU Affero General Public License
 * as published by the Free Software Foundation: version 3 of
 * the License.
 *
 * 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 Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 *
 * If needed, contact us to obtain a release under GPL Version 2 or 3
 * or a different license than the AGPL.
 */
package org.ow2.proactive.scheduler.examples;

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.PrintStream;
import java.io.Serializable;
import java.util.Map;
import java.util.Random;

import org.ow2.proactive.scheduler.common.task.TaskResult;
import org.ow2.proactive.scheduler.common.task.executable.JavaExecutable;


/**
 * MonteCarlo compute PI using MonteCarlo method.
 * This task can be launched with parameters.
 *
 * @author The ProActive Team
 */
public class MonteCarlo extends JavaExecutable {

    private static final long DEFAULT_STEPS = 10;

    private static final long DEFAULT_ITERATIONS = 10000;

    private long iterations = DEFAULT_ITERATIONS;

    private long steps = DEFAULT_STEPS;

    private String file = null;

    /**
     * @see JavaExecutable#init(Map)
     */
    @Override
    public void init(Map<String, Serializable> args) {
        if (args.containsKey("steps")) {
            try {
                steps = Long.parseLong(args.get("steps").toString());
            } catch (NumberFormatException e) {
            }
        }

        if (args.containsKey("iterations")) {
            try {
                iterations = Long.parseLong(args.get("iterations").toString());
            } catch (NumberFormatException e) {
            }
        }

        if (args.containsKey("file")) {
            file = args.get("file").toString();
        }
    }

    /**
     * @see JavaExecutable#execute(org.ow2.proactive.scheduler.common.task.TaskResult[])
     */
    @Override
    public Serializable execute(TaskResult... results) {
        Random rand = new Random(System.currentTimeMillis());
        long n = iterations;
        long print = iterations / steps;
        int nbPrint = 0;
        double res = 0;

        while (n > 0) {
            if (print < 0) {
                String progress = String.format("%02d", 100 - ((n * 100) / iterations));

                getOut().println("Intermediate value computed (" + progress + "%) for π is " +
                                 ((4 * res) / (((++nbPrint) * iterations) / steps)));

                print = iterations / steps;
            }

            double x = rand.nextDouble();
            double y = rand.nextDouble();

            if (((x * x) + (y * y)) < 1) {
                res++;
            }

            print--;
            n--;
        }

        Double result = new Double((4 * res) / iterations);

        if (file != null) {
            FileOutputStream f = null;

            try {
                f = new FileOutputStream(file);

                PrintStream ps = new PrintStream(f);
                ps.println("Computed π value using Montecarlo is: " + result);
                ps.close();
            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                try {
                    f.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return result;
    }

}