WMPI - функции коллективного обмена в MPI . Производные типы в MPI

#include <stdio.h>
#include <stddef.h>
#include <mpi.h>   
#include<iostream>
using namespace std;
typedef struct { long a[15]; unsigned char b[3]; float c[8]; } st;
int main(int argc, char * argv[]) {
    int me, size;
    st st1[3];
    int blocklens[] = { 15, 3, 8, 15 };
    MPI_Aint indices[] = { offsetof(st, a), offsetof(st, b), offsetof(st, c), sizeof (st) };
    MPI_Datatype old_types[] = { MPI_LONG, MPI_UNSIGNED_CHAR, MPI_FLOAT, MPI_UB };
    MPI_Datatype newtype;
    MPI_Init(&argc, &argv);
    MPI_Comm_rank(MPI_COMM_WORLD, &me);
    MPI_Type_struct(4, blocklens, indices, old_types, &newtype); MPI_Type_commit(&newtype);
    st1[0].a = 3.14, st1[0].b[0] = 12, st1[0].c[0] = 5.16;
    cout << " me=" << me << " before bcast " << st1[0].a << " " << st1[0].b[0] << " " << st1[0].c[0] << endl;
    if (me == 0)
    {
        st1[0].a = 1.11;
        st1[0].b[0] = 4;
        st1[0].c[0] = 5.16;
 
    }
    MPI_Bcast(st1, 1, newtype, 0, MPI_COMM_WORLD);
    cout << " me=" << me << " after " << st1[0].a << " " << st1[0].b[0] << " " << st1[0].c[0] << endl;
 
    MPI_Finalize();
    system("PAUSE");
    return 0;
}