sub2.java

MPI for java for Distributed Programming

package mpi.topo; 

import mpi.*;

public class sub2 {
  static public void main(String[] args) throws MPIException {
  }


  public sub2() {
  }

  public sub2(String[] args) throws Exception {

    int dims[] = new int[2];
    dims[0] = 2;  dims[1] = 3;
    boolean periods[] = new boolean[2];    
    int size,rank;
    MPI.Init(args);
    rank = MPI.COMM_WORLD.Rank();
    size =MPI.COMM_WORLD.Size(); 

    if(size != 8)  {
      if(rank == 0)
        System.out.println("topo->sub2: MUST RUN WITH 8 TASKS");
      
      MPI.COMM_WORLD.Barrier();
      MPI.Finalize();
      return;
    }

    Cartcomm comm = MPI.COMM_WORLD.Create_cart(dims,periods,false);   
    
    if(comm != null) {
    int[] dims2 = comm.Get().dims;
    boolean remain[] = new boolean[2];
    remain[0] = false;  remain[1] = true;
    Cartcomm subcomm = comm.Sub(remain);
    int nsize = subcomm.Size();
    int nrank = subcomm.Rank();
    
    System.out.println("rank <"+rank+">,nrank<"+nrank+">,size<"+size
		               +">,nsize <"+nsize);
    }else {
    System.out.println("rank <"+rank+",size<"+size+">");
    }

    MPI.COMM_WORLD.Barrier(); 
    MPI.Finalize();
  }
}