flow_global_two_dots_owned Subroutine

   subroutine flow_global_two_dots_owned(flow, a1, b1, a2, b2, results)
      use mod_profiling, only : profiler_start, profiler_stop
      type(flow_mpi_t), intent(in) :: flow
      real(rk), intent(in) :: a1(:), b1(:), a2(:), b2(:)
      real(rk), intent(out) :: results(2)
      real(rk) :: local_dots(2)
      integer :: c, ierr

      local_dots = zero
      do c = flow%first_cell, flow%last_cell
         local_dots(1) = local_dots(1) + a1(c) * b1(c)
         local_dots(2) = local_dots(2) + a2(c) * b2(c)
      end do

      if (flow%nprocs == 1) then
         results = local_dots
         return
      end if

      call profiler_start('MPI_Communication')
      call MPI_Allreduce(local_dots, results, 2, MPI_DOUBLE_PRECISION, MPI_SUM, flow%comm, ierr)
      call check_mpi(ierr, 'MPI_Allreduce two dots')
      call profiler_stop('MPI_Communication')
   end subroutine flow_global_two_dots_owned