/*  MPI_Type_contiguous example
 *
 */

#include <stdio.h>
#include "mpi.h"
#define N      16
#define blksz   4
int main(int argc, char *argv[])
{
     int nproc, rank, i;
     double a[N], b[N/blksz];
     MPI_Datatype myvec;
     MPI_Init(&argc, &argv);
     MPI_Comm_rank(MPI_COMM_WORLD, &rank);
     MPI_Comm_size(MPI_COMM_WORLD, &nproc);
     MPI_Type_contiguous(blksz, MPI_DOUBLE, &myvec);
     MPI_Type_commit(&myvec);

     /* initialize a[] on process #0 */

     if (rank == 0) 
          for (i=0; i<N; i++) { 
               a[i]=(double) i+1; 
               printf("rank=%d, a[%d]=%.1f\n",rank,i,a[i]);
          }

     MPI_Scatter(a,1,myvec,b,1,myvec,0,MPI_COMM_WORLD);
     /* One can also do: 
        MPI_Scatter(a,blksz,MPI_DOUBLE,
        b,blksz,MPI_DOUBLE,0,MPI_COMM_WORLD); 
     */
     for (i=0; i<blksz; i++) {
          printf("rank=%d b[%d]=%.1f\n",rank,i,b[i]);
     }
     MPI_Finalize(); 
     return 0;    
}