mg_highest_uniform_lvl Function

  pure function mg_highest_uniform_lvl(mg) result(lvl)
    type(mg_t), intent(in) :: mg
    integer                :: lvl

    do lvl = mg%first_normal_lvl, mg%highest_lvl-1
       ! Exit if a grid is partially refined
       if (size(mg%lvls(lvl)%leaves) /= 0 .and. size(mg%lvls(lvl)%parents) /= &
          0) exit
    end do
    ! If the loop did not exit, we get lvl equals mg%highest_lvl
  end function mg_highest_uniform_lvl