-Datatype::Datatype(char* name, int id, int size, MPI_Aint lb, MPI_Aint ub, int flags)
- : name_(name), id(id), size_(size), lb_(lb), ub_(ub), flags_(flags), refcount_(0)
+Datatype::Datatype(char* name, int ident, int size, MPI_Aint lb, MPI_Aint ub, int flags)
+ : name_(name), id(std::to_string(ident)), size_(size), lb_(lb), ub_(ub), flags_(flags), refcount_(0)