1 /* -*- Mode: C; c-basic-offset:4 ; indent-tabs-mode:nil ; -*- */
3 * (C) 2001 by Argonne National Laboratory.
4 * See COPYRIGHT in top-level directory.
10 /* This example sends a vector and receives individual elements */
12 int main(int argc, char **argv)
15 double *vecin, *vecout, ivalue;
16 int root, i, n, stride, err = 0;
19 MPI_Init(&argc, &argv);
21 MPI_Comm_size(MPI_COMM_WORLD, &size);
22 MPI_Comm_rank(MPI_COMM_WORLD, &rank);
26 vecin = (double *) malloc(n * stride * size * sizeof(double));
27 vecout = (double *) malloc(n * sizeof(double));
29 MPI_Type_vector(n, 1, stride, MPI_DOUBLE, &vec);
30 MPI_Type_commit(&vec);
32 for (i = 0; i < n * stride * size; i++)
33 vecin[i] = (double) i;
34 for (root = 0; root < size; root++) {
35 for (i = 0; i < n; i++)
37 MPI_Scatter(vecin, 1, vec, vecout, n, MPI_DOUBLE, root, MPI_COMM_WORLD);
38 ivalue = rank * ((n - 1) * stride + 1);
39 for (i = 0; i < n; i++) {
40 if (vecout[i] != ivalue) {
41 printf("Expected %f but found %f\n", ivalue, vecout[i]);
48 MPI_Allreduce(&i, &err, 1, MPI_INT, MPI_SUM, MPI_COMM_WORLD);
51 printf("Found %d errors!\n", err);
53 printf(" No Errors\n");