comm_setup Subroutine

   subroutine comm_setup()
      ! internal
      character(len=*), parameter :: this_procedure = 'comm_setup'
      character(len=128) :: msg
#ifdef MPI
      integer :: ierr, rank_local, size_local
      logical :: mpi_is_initialized

      call MPI_Initialized(mpi_is_initialized, ierr)
      if (.not. mpi_is_initialized) then
         call MPI_Init(ierr)
         if (ierr /= MPI_SUCCESS) call stop_error("Error initializing MPI", this_module, this_procedure)
      end if

      call MPI_Comm_rank(MPI_COMM_WORLD, rank_local, ierr)
      call MPI_Comm_size(MPI_COMM_WORLD, size_local, ierr)
      
      call set_rank(rank_local)
      call set_comm_size(size_local)

      if (rank_local==0) then
         call logger%log_message('Setup parallel run', this_module, this_procedure)
         write (msg, '(A,I0,A,I0)') 'comm_size = ', size_local
         call logger%log_message(trim(msg), this_module, this_procedure)
      end if
#else
      call set_rank(0)
      call set_comm_size(1)
      call logger%log_message('Setup serial run', this_module, this_procedure)
#endif
   end subroutine comm_setup