package mpi.comm;

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

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

    public intercomm_test() {
    }

    public intercomm_test(String[] args) 
	    throws Exception {

      MPI.Init(args); 	    
      int rank = MPI.COMM_WORLD.Rank();
      Group grp = MPI.COMM_WORLD.Group();
      int size = MPI.COMM_WORLD.Size(); 

      if(size < 8) {
        if(rank == 0)		    
          System.out.println("comm->intercomm_test: RUNS with 8 processes");
	
        MPI.COMM_WORLD.Barrier();
        MPI.Finalize(); 
        return;
      }
	    
      /* creating first intra-communicator */
      Intracomm comm1=null;
      int[] incl1 = { 0, 2, 4, 6};	   
      
      if( rank== 0 || rank==2|| rank==4 || rank==6 ) {		   
        Group grp1 = grp.Incl(incl1);	          
        comm1 = MPI.COMM_WORLD.Create(grp1);		 
      }

      /* creating first intra-communicator */
      Intracomm comm2=null;
      int[] incl2 = { 1, 3 , 5, 7};	   	    

      if( rank== 1 || rank==3|| rank==5 || rank==7 ) {		   
        Group grp2 = grp.Incl(incl2);	          
        comm2 = MPI.COMM_WORLD.Create(grp2);		 
      }

      Intercomm icomm = null; 
	    
      if( rank== 0 || rank==2|| rank==4 || rank==6 ) {		       
        icomm = MPI.COMM_WORLD.Create_intercomm(comm1,0,1,56);
      }

      if( rank== 1 || rank==3|| rank==5 || rank==7 ) {		         
        icomm = MPI.COMM_WORLD.Create_intercomm(comm2,1,0,56);
      }     
	    
      int [] testArray1 = new int[10];
      int [] testArray2 = new int[10];

      for(int i=0 ; i< testArray1.length ; i++) {
        testArray1[i] = i;	
	testArray2[i] = 0;
      }
	    
      //System.out.println("initialized them ...");
      if(rank == 2 ){			   
  	icomm.Send(testArray1, 0, 10, MPI.INT,2, 78);
  	MPI.COMM_WORLD.Send(testArray1, 0, 10, MPI.INT,5, 78);
      } else if(rank ==5) {	      
        icomm.Recv(testArray2, 0, 10, MPI.INT,1, 78);  
	if(Arrays.equals(testArray1, testArray2)) {
	  /*
	  System.out.println("****************"+
	  "***PASSED*******"+
	  "****************");
          */   				       
	}
      
      }	    
      
      MPI.COMM_WORLD.Barrier();

      if(rank == 5) {
        System.out.println("intercomm_test TEST COMPLETE");	    
      }
      
      MPI.Finalize();
    }

}