--- /dev/null
+/* Copyright (c) 2013-2014. The SimGrid Team.
+ * All rights reserved. */
+
+/* This program is free software; you can redistribute it and/or modify it
+ * under the terms of the license (GNU LGPL) which comes with this package. */
+
+#include "colls_private.h"
+
+int smpi_coll_tuned_allgather_loosely_lr(void *sbuf, int scount,
+ MPI_Datatype stype, void *rbuf,
+ int rcount, MPI_Datatype rtype,
+ MPI_Comm comm)
+{
+ int comm_size, rank;
+ int tag = COLL_TAG_ALLGATHER;
+ int i, j, send_offset, recv_offset;
+ int intra_rank, inter_rank, inter_comm_size, intra_comm_size;
+ int inter_dst, inter_src;
+
+ comm_size = smpi_comm_size(comm);
+
+if(smpi_comm_get_leaders_comm(comm)==MPI_COMM_NULL){
+ smpi_comm_init_smp(comm);
+ }
+ int num_core=1;
+ if (smpi_comm_is_uniform(comm)){
+ num_core = smpi_comm_size(smpi_comm_get_intra_comm(comm));
+ }
+
+ if(comm_size%num_core)
+ THROWF(arg_error,0, "allgather loosely lr algorithm can't be used with non multiple of NUM_CORE=%d number of processes ! ",num_core);
+
+ rank = smpi_comm_rank(comm);
+ MPI_Aint rextent, sextent;
+ rextent = smpi_datatype_get_extent(rtype);
+ sextent = smpi_datatype_get_extent(stype);
+ MPI_Request inter_rrequest;
+ MPI_Request rrequest_array[128];
+ MPI_Request srequest_array[128];
+ MPI_Request inter_srequest_array[128];
+
+
+ int rrequest_count = 0;
+ int srequest_count = 0;
+ int inter_srequest_count = 0;
+
+ MPI_Status status;
+
+ intra_rank = rank % num_core;
+ inter_rank = rank / num_core;
+ inter_comm_size = (comm_size + num_core - 1) / num_core;
+ intra_comm_size = num_core;
+
+ int src_seg, dst_seg;
+
+ //copy corresponding message from sbuf to rbuf
+ recv_offset = rank * rextent * rcount;
+ smpi_mpi_sendrecv(sbuf, scount, stype, rank, tag,
+ (char *)rbuf + recv_offset, rcount, rtype, rank, tag, comm, &status);
+
+ int dst, src;
+ int inter_send_offset, inter_recv_offset;
+
+ rrequest_count = 0;
+ srequest_count = 0;
+ inter_srequest_count = 0;
+
+ for (i = 0; i < inter_comm_size; i++) {
+
+ // inter_communication
+
+ inter_dst = (rank + intra_comm_size) % comm_size;
+ inter_src = (rank - intra_comm_size + comm_size) % comm_size;
+
+ src_seg =
+ ((inter_rank - 1 - i +
+ inter_comm_size) % inter_comm_size) * intra_comm_size + intra_rank;
+ dst_seg =
+ ((inter_rank - i +
+ inter_comm_size) % inter_comm_size) * intra_comm_size + intra_rank;
+
+ inter_send_offset = dst_seg * sextent * scount;
+ inter_recv_offset = src_seg * rextent * rcount;
+
+ for (j = 0; j < intra_comm_size; j++) {
+
+ // inter communication
+ if (intra_rank == j) {
+ if (i != inter_comm_size - 1) {
+
+ inter_rrequest = smpi_mpi_irecv((char *)rbuf + inter_recv_offset, rcount, rtype,
+ inter_src, tag, comm);
+ inter_srequest_array[inter_srequest_count++] = smpi_mpi_isend((char *)rbuf + inter_send_offset, scount, stype,
+ inter_dst, tag, comm);
+ }
+ }
+ //intra_communication
+ src = inter_rank * intra_comm_size + j;
+ dst = inter_rank * intra_comm_size + j;
+
+ src_seg =
+ ((inter_rank - i +
+ inter_comm_size) % inter_comm_size) * intra_comm_size + j;
+ dst_seg =
+ ((inter_rank - i +
+ inter_comm_size) % inter_comm_size) * intra_comm_size + intra_rank;
+
+ send_offset = dst_seg * sextent * scount;
+ recv_offset = src_seg * rextent * rcount;
+
+
+ if (j != intra_rank) {
+
+ rrequest_array[rrequest_count++] = smpi_mpi_irecv((char *)rbuf + recv_offset, rcount, rtype, src, tag, comm);
+ srequest_array[srequest_count++] = smpi_mpi_isend((char *)rbuf + send_offset, scount, stype, dst, tag, comm);
+
+ }
+ } // intra loop
+
+
+ // wait for inter communication to finish for these rounds (# of round equals num_core)
+ if (i != inter_comm_size - 1) {
+ smpi_mpi_wait(&inter_rrequest, &status);
+ }
+
+ } //inter loop
+
+ smpi_mpi_waitall(rrequest_count, rrequest_array, MPI_STATUSES_IGNORE);
+ smpi_mpi_waitall(srequest_count, srequest_array, MPI_STATUSES_IGNORE);
+ smpi_mpi_waitall(inter_srequest_count, inter_srequest_array, MPI_STATUSES_IGNORE);
+
+ return MPI_SUCCESS;
+}
