1 /* Copyright (c) 2013-2014. 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.h"
9 /*****************************************************************************
11 * Function: alltoall_pair
16 send_buff: send input buffer
17 send_count: number of elements to send
18 send_type: data type of elements being sent
19 recv_buff: receive output buffer
20 recv_count: number of elements to received
21 recv_type: data type of elements being received
24 * Descrp: Function works when P is power of two. In each phase of P - 1
25 phases, nodes in pair communicate their data.
29 ****************************************************************************/
30 int smpi_coll_tuned_alltoallv_pair(void *send_buff, int *send_counts, int *send_disps,
31 MPI_Datatype send_type,
32 void *recv_buff, int *recv_counts, int *recv_disps,
33 MPI_Datatype recv_type, MPI_Comm comm)
36 MPI_Aint send_chunk, recv_chunk;
38 int i, src, dst, rank, num_procs;
39 int tag = COLL_TAG_ALLTOALLV;
40 char *send_ptr = (char *) send_buff;
41 char *recv_ptr = (char *) recv_buff;
43 rank = smpi_comm_rank(comm);
44 num_procs = smpi_comm_size(comm);
46 if((num_procs&(num_procs-1)))
47 THROWF(arg_error,0, "alltoallv pair algorithm can't be used with non power of two number of processes ! ");
49 send_chunk = smpi_datatype_get_extent(send_type);
50 recv_chunk = smpi_datatype_get_extent(recv_type);
52 for (i = 0; i < num_procs; i++) {
54 smpi_mpi_sendrecv(send_ptr + send_disps[dst] * send_chunk, send_counts[dst], send_type, dst, tag,
55 recv_ptr + recv_disps[src] * recv_chunk, recv_counts[src], recv_type, src, tag,