1 /* -*- Mode: C; c-basic-offset:4 ; indent-tabs-mode:nil ; -*- */
4 * (C) 2003 by Argonne National Laboratory.
5 * See COPYRIGHT in top-level directory.
13 /* Gather data from a vector to contiguous */
15 int main(int argc, char **argv)
19 double *vecin, *vecout;
20 int minsize = 2, count;
21 int root, i, n, stride, errs = 0;
24 MTest_Init(&argc, &argv);
26 while (MTestGetIntracommGeneral(&comm, minsize, 1)) {
27 if (comm == MPI_COMM_NULL)
29 /* Determine the sender and receiver */
30 MPI_Comm_rank(comm, &rank);
31 MPI_Comm_size(comm, &size);
33 for (root = 0; root < size; root++) {
34 for (count = 1; count < 65000; count = count * 2) {
37 vecin = (double *) malloc(n * stride * size * sizeof(double));
38 vecout = (double *) malloc(size * n * sizeof(double));
40 MPI_Type_vector(n, 1, stride, MPI_DOUBLE, &vec);
41 MPI_Type_commit(&vec);
43 for (i = 0; i < n * stride; i++)
45 for (i = 0; i < n; i++)
46 vecin[i * stride] = rank * n + i;
48 MPI_Gather(vecin, 1, vec, vecout, n, MPI_DOUBLE, root, comm);
51 for (i = 0; i < n * size; i++) {
55 fprintf(stderr, "vecout[%d]=%d\n", i, (int) vecout[i]);
68 /* do a zero length gather */
69 MPI_Gather(NULL, 0, MPI_BYTE, NULL, 0, MPI_BYTE, 0, MPI_COMM_WORLD);