The function MPIManager::receive() determines whether the mesh should
be received from another process instead of created, according to the
current policy for communication. Right now, only one policy is
implemented but this may change (depending on for example whether the
user wants to take care of communication or let's DOLFIN decide on a
suitable policy). The current implementation just returns
return numProcesses() > 0 && processNumber() > 0;
If MPI is not available it just returns false.
Similarly, the function MPIManager::broadcast() determines whether the
mesh should be broadcast to all other processes:
return numProcesses() > 0 && processNumber() == 0;