protect (hopefully) collective communication algorithms from abuse.

[simgrid.git] / src / smpi / colls / allgather-2dmesh.c

diff --git a/src/smpi/colls/allgather-2dmesh.c b/src/smpi/colls/allgather-2dmesh.c
index 602d540..8ebc848 100644 (file)
--- a/src/smpi/colls/allgather-2dmesh.c
+++ b/src/smpi/colls/allgather-2dmesh.c
@@ -120,7 +120,7 @@ smpi_coll_tuned_allgather_2dmesh(void *send_buff, int send_count, MPI_Datatype
   block_size = extent * send_count;
 
   if (!is_2dmesh(num_procs, &X, &Y))
-    return MPI_ERR_COMM;
+    THROWF(arg_error,0, "allgather_2dmesh algorithm can't be used with this number of processes! ");
 
   my_row_base = (rank / Y) * Y;
   my_col_base = rank % Y;