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.
11 /* Fetch and add example from Using MPI-2 (the non-scalable version,
14 /* same as fetchandadd.c but uses alloc_mem */
16 #define NTIMES 20 /* no of times each process calls the counter
19 int localvalue = 0; /* contribution of this process to the counter. We
20 * define it as a global variable because attribute
21 * caching on the window is not enabled yet. */
23 void Get_nextval(MPI_Win win, int *val_array, MPI_Datatype get_type,
24 int rank, int nprocs, int *value);
26 int compar(const void *a, const void *b);
28 int main(int argc, char *argv[])
30 int rank, nprocs, i, blens[2], disps[2], *counter_mem, *val_array, *results, *counter_vals;
31 MPI_Datatype get_type;
35 MTest_Init(&argc, &argv);
36 MPI_Comm_size(MPI_COMM_WORLD, &nprocs);
37 MPI_Comm_rank(MPI_COMM_WORLD, &rank);
40 /* allocate counter memory and initialize to 0 */
41 /* counter_mem = (int *) calloc(nprocs, sizeof(int)); */
43 i = MPI_Alloc_mem(nprocs * sizeof(int), MPI_INFO_NULL, &counter_mem);
45 printf("Can't allocate memory in test program\n");
46 MPI_Abort(MPI_COMM_WORLD, 1);
49 for (i = 0; i < nprocs; i++)
52 MPI_Win_create(counter_mem, nprocs * sizeof(int), sizeof(int),
53 MPI_INFO_NULL, MPI_COMM_WORLD, &win);
56 MPI_Free_mem(counter_mem);
58 /* gather the results from other processes, sort them, and check
59 * whether they represent a counter being incremented by 1 */
61 results = (int *) malloc(NTIMES * nprocs * sizeof(int));
62 for (i = 0; i < NTIMES * nprocs; i++)
65 MPI_Gather(MPI_IN_PLACE, 0, MPI_DATATYPE_NULL, results, NTIMES, MPI_INT, 0, MPI_COMM_WORLD);
67 qsort(results + NTIMES, NTIMES * (nprocs - 1), sizeof(int), compar);
69 for (i = NTIMES + 1; i < (NTIMES * nprocs); i++)
70 if (results[i] != results[i - 1] + 1)
78 blens[1] = nprocs - rank - 1;
81 MPI_Type_indexed(2, blens, disps, MPI_INT, &get_type);
82 MPI_Type_commit(&get_type);
84 val_array = (int *) malloc(nprocs * sizeof(int));
86 /* allocate array to store the values obtained from the
87 * fetch-and-add counter */
88 counter_vals = (int *) malloc(NTIMES * sizeof(int));
90 MPI_Win_create(NULL, 0, 1, MPI_INFO_NULL, MPI_COMM_WORLD, &win);
92 for (i = 0; i < NTIMES; i++) {
93 Get_nextval(win, val_array, get_type, rank, nprocs, counter_vals + i);
94 /* printf("Rank %d, counter %d\n", rank, value); */
100 MPI_Type_free(&get_type);
102 /* gather the results to the root */
103 MPI_Gather(counter_vals, NTIMES, MPI_INT, NULL, 0, MPI_DATATYPE_NULL, 0, MPI_COMM_WORLD);
107 MTest_Finalize(errs);
113 void Get_nextval(MPI_Win win, int *val_array, MPI_Datatype get_type,
114 int rank, int nprocs, int *value)
118 MPI_Win_lock(MPI_LOCK_EXCLUSIVE, 0, 0, win);
119 MPI_Accumulate(&one, 1, MPI_INT, 0, rank, 1, MPI_INT, MPI_SUM, win);
120 MPI_Get(val_array, 1, get_type, 0, 0, 1, get_type, win);
121 MPI_Win_unlock(0, win);
124 val_array[rank] = localvalue;
125 for (i = 0; i < nprocs; i++)
126 *value = *value + val_array[i];
131 int compar(const void *a, const void *b)
133 return (*((int *) a) - *((int *) b));