--- /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"
+//#include <star-reduction.c>
+
+// this requires that count >= NP
+int smpi_coll_tuned_allreduce_rab2(void *sbuff, void *rbuff,
+ int count, MPI_Datatype dtype,
+ MPI_Op op, MPI_Comm comm)
+{
+ MPI_Aint s_extent;
+ int i, rank, nprocs;
+ int nbytes, send_size, s_offset, r_offset;
+ void *recv, *send, *tmp;
+ /*
+ #ifdef MPICH2_REDUCTION
+ MPI_User_function * uop = MPIR_Op_table[op % 16 - 1];
+ #else
+ MPI_User_function *uop;
+ struct MPIR_OP *op_ptr;
+ op_ptr = MPIR_ToPointer(op);
+ uop = op_ptr->op;
+ #endif
+ */
+ rank = smpi_comm_rank(comm);
+ nprocs = smpi_comm_size(comm);
+
+
+ s_extent = smpi_datatype_get_extent(dtype);
+
+ // uneven count
+ if (count % nprocs) {
+ if (count < nprocs)
+ send_size = nprocs;
+ else
+ send_size = (count + nprocs) / nprocs;
+ nbytes = send_size * s_extent;
+
+ send = (void *) smpi_get_tmp_sendbuffer(s_extent * send_size * nprocs);
+ recv = (void *) smpi_get_tmp_recvbuffer(s_extent * send_size * nprocs);
+ tmp = (void *) smpi_get_tmp_sendbuffer(nbytes);
+
+ memcpy(send, sbuff, s_extent * count);
+
+ mpi_coll_alltoall_fun(send, send_size, dtype, recv, send_size, dtype, comm);
+
+ memcpy(tmp, recv, nbytes);
+
+ for (i = 1, s_offset = nbytes; i < nprocs; i++, s_offset = i * nbytes)
+ smpi_op_apply(op, (char *) recv + s_offset, tmp, &send_size, &dtype);
+
+ mpi_coll_allgather_fun(tmp, send_size, dtype, recv, send_size, dtype, comm);
+ memcpy(rbuff, recv, count * s_extent);
+
+ smpi_free_tmp_buffer(recv);
+ smpi_free_tmp_buffer(tmp);
+ smpi_free_tmp_buffer(send);
+ } else {
+ send = sbuff;
+ send_size = count / nprocs;
+ nbytes = send_size * s_extent;
+ r_offset = rank * nbytes;
+
+ recv = (void *) smpi_get_tmp_recvbuffer(s_extent * send_size * nprocs);
+
+ mpi_coll_alltoall_fun(send, send_size, dtype, recv, send_size, dtype, comm);
+
+ memcpy((char *) rbuff + r_offset, recv, nbytes);
+
+ for (i = 1, s_offset = nbytes; i < nprocs; i++, s_offset = i * nbytes)
+ smpi_op_apply(op, (char *) recv + s_offset, (char *) rbuff + r_offset,
+ &send_size, &dtype);
+
+ mpi_coll_allgather_fun((char *) rbuff + r_offset, send_size, dtype, rbuff, send_size,
+ dtype, comm);
+ smpi_free_tmp_buffer(recv);
+ }
+
+ return MPI_SUCCESS;
+}