1 /*
2 * Copyright (c) 2004-2005 The Trustees of Indiana University and Indiana
3 * University Research and Technology
4 * Corporation. All rights reserved.
5 * Copyright (c) 2004-2015 The University of Tennessee and The University
6 * of Tennessee Research Foundation. All rights
7 * reserved.
8 * Copyright (c) 2004-2005 High Performance Computing Center Stuttgart,
9 * University of Stuttgart. All rights reserved.
10 * Copyright (c) 2004-2005 The Regents of the University of California.
11 * All rights reserved.
12 * Copyright (c) 2015 Research Organization for Information Science
13 * and Technology (RIST). All rights reserved.
14 * $COPYRIGHT$
15 *
16 * Additional copyrights may follow
17 *
18 * $HEADER$
19 */
20
21 #include "ompi_config.h"
22 #include "coll_basic.h"
23
24 #include "mpi.h"
25 #include "ompi/constants.h"
26 #include "coll_basic.h"
27 #include "ompi/datatype/ompi_datatype.h"
28 #include "ompi/mca/coll/coll.h"
29 #include "ompi/mca/coll/base/coll_tags.h"
30 #include "ompi/mca/pml/pml.h"
31
32
33 /*
34 * gather_inter
35 *
36 * Function: - basic gather operation
37 * Accepts: - same arguments as MPI_Gather()
38 * Returns: - MPI_SUCCESS or error code
39 */
40 int
41 mca_coll_basic_gather_inter(const void *sbuf, int scount,
42 struct ompi_datatype_t *sdtype,
43 void *rbuf, int rcount,
44 struct ompi_datatype_t *rdtype,
45 int root, struct ompi_communicator_t *comm,
46 mca_coll_base_module_t *module)
47 {
48 int i;
49 int err;
50 int size;
51 char *ptmp;
52 MPI_Aint incr;
53 MPI_Aint extent;
54 MPI_Aint lb;
55
56 size = ompi_comm_remote_size(comm);
57
58 if (MPI_PROC_NULL == root) {
59 /* do nothing */
60 err = OMPI_SUCCESS;
61 } else if (MPI_ROOT != root) {
62 /* Everyone but root sends data and returns. */
63 err = MCA_PML_CALL(send(sbuf, scount, sdtype, root,
64 MCA_COLL_BASE_TAG_GATHER,
65 MCA_PML_BASE_SEND_STANDARD, comm));
66 } else {
67 /* I am the root, loop receiving the data. */
68 err = ompi_datatype_get_extent(rdtype, &lb, &extent);
69 if (OMPI_SUCCESS != err) {
70 return OMPI_ERROR;
71 }
72
73 incr = extent * rcount;
74 for (i = 0, ptmp = (char *) rbuf; i < size; ++i, ptmp += incr) {
75 err = MCA_PML_CALL(recv(ptmp, rcount, rdtype, i,
76 MCA_COLL_BASE_TAG_GATHER,
77 comm, MPI_STATUS_IGNORE));
78 if (MPI_SUCCESS != err) {
79 return err;
80 }
81 }
82 }
83
84 /* All done */
85 return err;
86 }