contiguous.java

MPI for java for Distributed Programming

package mpi.dtyp;

import mpi.*;
import java.util.Arrays;

/**
 * This example application, is to check and demonstrat the functonality 
 * of contiguous datatypes. I'm writing an MPJ program by coverting a C 
 * program by Forest Hoffman at following URL
 * http://www.linux-mag.com/2003-04/extreme_01.html
 */ 

public class Contiguous {
  public static int NUM_PARAMS=12;
  public static void main (String args[]) throws Exception{
  }

  public Contiguous() {
  }

  public Contiguous(String[] args) throws Exception {

    MPI.Init(args); 	    
    int i, rank, size;
	    
    double [] params = new double[NUM_PARAMS];	    
    double [] rparams = new double[NUM_PARAMS];
	    
    rank = MPI.COMM_WORLD.Rank();	    
    size = MPI.COMM_WORLD.Size();
    Datatype parameterType;

    /* only the first process reads the parameters */
    if(rank == 0) {
      for(i=0 ; i<NUM_PARAMS ; i++) {
        params[i]=(double) (i*i);
      }
    }
		
    parameterType = Datatype.Contiguous(NUM_PARAMS, MPI.DOUBLE);
    parameterType.Commit(); //this is doing nothing at the moment.	    
	   
    if (rank  == 1) {
      MPI.COMM_WORLD.Recv(rparams,0,1,parameterType,0,10);   	    
      System.out.println("recv completed");
		    
      for(int j=0 ; j<rparams.length ; j++) {
        System.out.print("rparams["+j+"]="+rparams[j]+"\t");
      }
		    
      /* work out what would be test ? 
      if (Arrays.equals(source,dest)) {
        System.out.println("PASS");
      }else {
        System.out.println("\n****");
        System.out.println("FAIL");
        System.out.println("****");
      }*/
    }else if(rank == 0) {	 
      MPI.COMM_WORLD.Send(params,0,1,parameterType,1, 10);
      System.out.println("Send Completed");	    		  
    }
    
    MPI.COMM_WORLD.Barrier();
    MPI.Finalize();
  }
}