protect (hopefully) collective communication algorithms from abuse.

[simgrid.git] / src / smpi / colls / alltoall-pair-one-barrier.c

diff --git a/src/smpi/colls/alltoall-pair-one-barrier.c b/src/smpi/colls/alltoall-pair-one-barrier.c
index 209fa81..b230402 100644 (file)
--- a/src/smpi/colls/alltoall-pair-one-barrier.c
+++ b/src/smpi/colls/alltoall-pair-one-barrier.c
@@ -37,6 +37,10 @@ smpi_coll_tuned_alltoall_pair_one_barrier(void *send_buff, int send_count,
 
   rank = smpi_comm_rank(comm);
   num_procs = smpi_comm_size(comm);
+
+  if((num_procs&(num_procs-1)))
+    THROWF(arg_error,0, "alltoall pair algorithm can't be used with non power of two number of processes ! ");
+
   send_chunk = smpi_datatype_get_extent(send_type);
   recv_chunk = smpi_datatype_get_extent(recv_type);