int smpi_group_rank(MPI_Group group, int index)
{
int * ptr_rank = nullptr;
+ if (group==MPI_GROUP_EMPTY)
+ return MPI_UNDEFINED;
char * key = bprintf("%d", index);
ptr_rank = static_cast<int*>(xbt_dict_get_or_null(group->index_to_rank_map, key));
xbt_free(key);