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,
31 *results, *counter_vals;
32 MPI_Datatype get_type;
36 MTest_Init(&argc,&argv);
37 MPI_Comm_size(MPI_COMM_WORLD,&nprocs);
38 MPI_Comm_rank(MPI_COMM_WORLD,&rank);
41 /* allocate counter memory and initialize to 0 */
42 /* counter_mem = (int *) calloc(nprocs, sizeof(int)); */
44 i = MPI_Alloc_mem(nprocs*sizeof(int), MPI_INFO_NULL, &counter_mem);
46 printf("Can't allocate memory in test program\n");
47 MPI_Abort(MPI_COMM_WORLD, 1);
50 for (i=0; i<nprocs; i++) counter_mem[i] = 0;
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,
68 qsort(results+NTIMES, NTIMES*(nprocs-1), sizeof(int), compar);
70 for (i=NTIMES+1; i<(NTIMES*nprocs); i++)
71 if (results[i] != results[i-1] + 1)
79 blens[1] = nprocs - rank - 1;
82 MPI_Type_indexed(2, blens, disps, MPI_INT, &get_type);
83 MPI_Type_commit(&get_type);
85 val_array = (int *) malloc(nprocs * sizeof(int));
87 /* allocate array to store the values obtained from the
88 fetch-and-add counter */
89 counter_vals = (int *) malloc(NTIMES * sizeof(int));
91 MPI_Win_create(NULL, 0, 1, MPI_INFO_NULL, MPI_COMM_WORLD, &win);
93 for (i=0; i<NTIMES; i++) {
94 Get_nextval(win, val_array, get_type, rank, nprocs, counter_vals+i);
95 /* printf("Rank %d, counter %d\n", rank, value); */
101 MPI_Type_free(&get_type);
103 /* gather the results to the root */
104 MPI_Gather(counter_vals, NTIMES, MPI_INT, NULL, 0, MPI_DATATYPE_NULL,
109 MTest_Finalize(errs);
115 void Get_nextval(MPI_Win win, int *val_array, MPI_Datatype get_type,
116 int rank, int nprocs, int *value)
120 MPI_Win_lock(MPI_LOCK_EXCLUSIVE, 0, 0, win);
121 MPI_Accumulate(&one, 1, MPI_INT, 0, rank, 1, MPI_INT, MPI_SUM, win);
122 MPI_Get(val_array, 1, get_type, 0, 0, 1, get_type, win);
123 MPI_Win_unlock(0, win);
126 val_array[rank] = localvalue;
127 for (i=0; i<nprocs; i++)
128 *value = *value + val_array[i];
133 int compar(const void *a, const void *b)
135 return (*((int *)a) - *((int *)b));