1 /* Copyright (c) 2013-2020. The SimGrid Team.
2 * All rights reserved. */
4 /* This program is free software; you can redistribute it and/or modify it
5 * under the terms of the license (GNU LGPL) which comes with this package. */
7 #include "../colls_private.hpp"
8 /*****************************************************************************
10 * Function: alltoall_ring
15 send_buff: send input buffer
16 send_count: number of elements to send
17 send_type: data type of elements being sent
18 recv_buff: receive output buffer
19 recv_count: number of elements to received
20 recv_type: data type of elements being received
23 * Descrp: Function works in P - 1 steps. In step i, node j - i -> j -> j + i.
27 ****************************************************************************/
30 int alltoallv__ring_one_barrier(const void *send_buff, const int *send_counts, const int *send_disps,
31 MPI_Datatype send_type,
32 void *recv_buff, const int *recv_counts, const int *recv_disps,
33 MPI_Datatype recv_type, MPI_Comm comm)
36 MPI_Aint send_chunk, recv_chunk;
37 int i, src, dst, rank, num_procs;
38 int tag = COLL_TAG_ALLTOALLV;
40 char *send_ptr = (char *) send_buff;
41 char *recv_ptr = (char *) recv_buff;
44 num_procs = comm->size();
45 send_chunk = send_type->get_extent();
46 recv_chunk = recv_type->get_extent();
49 for (i = 0; i < num_procs; i++) {
50 src = (rank - i + num_procs) % num_procs;
51 dst = (rank + i) % num_procs;
53 Request::sendrecv(send_ptr + send_disps[dst] * send_chunk, send_counts[dst], send_type, dst,
54 tag, recv_ptr + recv_disps[src] * recv_chunk, recv_counts[src], recv_type,