radiation_task_bounds Subroutine

   subroutine radiation_task_bounds(rad, n_tasks)
      type(radiation_mpi_t), intent(inout) :: rad
      integer, intent(in) :: n_tasks

      integer :: base, rem

      if (n_tasks < 0) call fatal_error('mpi_radiation', 'n_tasks cannot be negative')
      if (rad%nprocs <= 0) call fatal_error('mpi_radiation', 'radiation communicator is not initialized')

      base = n_tasks / rad%nprocs
      rem = mod(n_tasks, rad%nprocs)

      if (rad%rank < rem) then
         rad%nlocal_tasks = base + 1
         rad%first_task = rad%rank * (base + 1) + 1
      else
         rad%nlocal_tasks = base
         rad%first_task = rem * (base + 1) + (rad%rank - rem) * base + 1
      end if
      rad%last_task = rad%first_task + rad%nlocal_tasks - 1
      rad%first_wavenumber = rad%first_task
      rad%last_wavenumber = rad%last_task
      rad%nlocal_wavenumbers = rad%nlocal_tasks
   end subroutine radiation_task_bounds