/* Skandium: A Java(TM) based parallel skeleton library.
*
* Copyright (C) 2009 NIC Labs, Universidad de Chile.
*
* Skandium 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
* (at your option) any later version.
*
* Skandium 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 Skandium. If not, see <http://www.gnu.org/licenses/>.
*/
package cl.niclabs.skandium.examples.nqueensnaive;
import java.util.Random;
import java.util.concurrent.Future;
import cl.niclabs.skandium.skeletons.Map;
import cl.niclabs.skandium.skeletons.DaC;
import cl.niclabs.skandium.skeletons.Skeleton;
import cl.niclabs.skandium.Skandium;
import cl.niclabs.skandium.Stream;
/**
* The main class to execute a naive NQueens counting algorithm which does not consider board symmetries.
*
* @author mleyton
*/
public class NQueens{
static Random random = new Random();
public static void main(String[] args) throws Exception {
int THREADS = Runtime.getRuntime().availableProcessors();
int BOARD = 15; //Size board of the board
int DEPTH = 3;
if(args.length != 0) {
THREADS = Integer.parseInt(args[0]);
BOARD = Integer.parseInt(args[1]);
DEPTH = Integer.parseInt(args[2]);
}
System.out.println("Computing NQueens threads="+THREADS+" board="+ BOARD+" depth="+DEPTH+ ".");
//1. Define the skeleton program structure
Skeleton<Board, Count> subskel = new DaC<Board, Count>( //We use a divide and conquer skeleton pattern
new ShouldDivide(DEPTH), //Dive until the depth is "N-3"
new DivideBoard(),
new Solve(),
new ConquerCount());
Skeleton<Board, Count> nqueens = //Always subdivide the first row.
new Map<Board, Count>(new DivideBoard(), subskel, new ConquerCount());
//2. Create a new Skandium instance with 2 execution threads
Skandium skandium = new Skandium(THREADS);
//3. Open a Stream to input parameters
Stream<Board, Count> stream = skandium.newStream(nqueens);
//4. Input parameters
long init = System.currentTimeMillis();
Future<Count> future = stream.input(new Board(BOARD));
//5. Do something else here.
//...
//6. Block for the results
Count result = future.get();
System.out.println(result+" in "+(System.currentTimeMillis() - init)+"[ms]");
//7. Shutdown the system
skandium.shutdown();
}
}