cart_topo.java

MPI for java for Distributed Programming

package mpi.topo; 
import mpi.*;

public class cart_topo {
  public static void main(String[] args) throws Exception {
  }

  public cart_topo() {
  }

  public cart_topo(String[] args) throws Exception {

    MPI.Init(args);
    Group group = MPI.COMM_WORLD.Group();
    int processes = group.Size();
    int rank = group.Rank();   

    if(processes<8) {
      if(rank == 0) 
        System.out.println("topo->cart_topo: MUST RUN WITH 8 tasks");

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

    /* checking two dimensional cartesian topology 
    int dims2[] = new int[2]; 
    dims2[0] = 2;  
    dims2[1] = 2;    
    
    boolean periods2[] = new boolean[2];
    periods2[0] = false;
    periods2[1] = false;
    Cartcomm comm = MPI.COMM_WORLD.Create_cart(dims2,periods2,false);     
    
    int[] c = new int[2];

    for(int i=0 ; i<2 ; i++) {
	for(int j=0 ; j<2 ; j++) {
	    c[0]= i;
	    c[1]= j;

if(rank == 0) {    
System.out.println("rank =<"+comm.Rank(c)+">,i=<"+c[0]+">=j<"+c[1]);
}

	}
    }
	
     checking three dimensional cartesian topology */
    int dims3[] = new int[3]; 
    dims3[0] = 2;  
    dims3[1] = 2;        
    dims3[2] = 2;    
    
    boolean periods3[] = new boolean[3];
    periods3[0] = false;
    periods3[1] = false;
    periods3[2] = false;
    
    Cartcomm comm2 = MPI.COMM_WORLD.Create_cart(dims3,periods3,false); 
    int[] c1 = new int[3];
if(rank == 0)    
System.out.println("\ncoords to ranks (3D)\n");   
    for(int i=0 ; i<2 ; i++) {
	for(int j=0 ; j<2 ; j++) {
	    for(int k=0 ; k<2 ; k++) {
		    
 	        c1[0]= i;
	        c1[1]= j;
		c1[2]= k;

if(rank == 0) {    
    System.out.println("rank =<"+comm2.Rank(c1)+">,i=<"+c1[0]+
		    ">=j<"+c1[1]+">,k=<"+c1[2]);      			
}
	    }
	}
    }
/*
if(rank == 0)    
System.out.println("\nranks to coords (3D)\n");

    for(int i=0 ; i<comm2.Size()  ; i++) {		
	int[] ct = new int[3];
	ct = comm2.Coords(i);	

if(rank == 0) {    
    System.out.println("rank =<"+i+">,i=<"+ct[0]+
		    ">=j<"+ct[1]+">,k=<"+ct[2]);      			
}
    }
*/    

    //try { Thread.currentThread().sleep(10000); }catch(Exception e){}	
    MPI.COMM_WORLD.Barrier();
    MPI.Finalize();
  }//end main

}