protect (hopefully) collective communication algorithms from abuse.

[simgrid.git] / src / smpi / colls / alltoallv-pair.c

diff --git a/src/smpi/colls/alltoallv-pair.c b/src/smpi/colls/alltoallv-pair.c
index 50839df..afce437 100644 (file)
--- a/src/smpi/colls/alltoallv-pair.c
+++ b/src/smpi/colls/alltoallv-pair.c
@@ -30,12 +30,16 @@ int smpi_coll_tuned_alltoallv_pair(void *send_buff, int *send_counts, int *send_
   MPI_Aint send_chunk, recv_chunk;
   MPI_Status s;
   int i, src, dst, rank, num_procs;
-  int tag = 1;
+  int tag = COLL_TAG_ALLTOALLV;
   char *send_ptr = (char *) send_buff;
   char *recv_ptr = (char *) recv_buff;
 
   rank = smpi_comm_rank(comm);
   num_procs = smpi_comm_size(comm);
+
+  if((num_procs&(num_procs-1)))
+    THROWF(arg_error,0, "alltoallv 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);