An opaque wrapper for MPI_Comm with a vendor-independent representation without any <mpi....
void reset() noexcept
Reset to default constructed value (MPI_COMM_NULL).
Communicator(const Communicator &) noexcept=default
Copy construct.
bool good() const noexcept
True if not equal to MPI_COMM_NULL.
Communicator() noexcept
Default construct as MPI_COMM_NULL.
int size() const
The number of ranks associated with the communicator.
static Communicator lookup(int communicator=-1)
Transcribe internally indexed communicator to wrapped value.
UPstream(const commsTypes commsType) noexcept
Construct for given communication type.