need_load_balancing Function

public function need_load_balancing(lt_imb) result(t_lb)

Gauge if a load balancing step shall be taken given the current load-imbalance measure lt_imb during the last 100 iterations divided by the total time taken for these

Arguments

Type IntentOptional Attributes Name
real(kind=dp), intent(in) :: lt_imb

current load imbalance measure: Time lost due to load imbalance

Return Value logical


Source Code

    function need_load_balancing(lt_imb) result(t_lb)
        real(dp), intent(in) :: lt_imb
        logical :: t_lb

        real(dp), save :: last_imb = 0.0_dp
        logical, save :: last_t_lb = .false.

        ! In the cycle immediately after a load balancing step, we do not load balance
        ! again, but instead log the imbalance measure for comparison
        if (last_t_lb) then
            last_imb = lt_imb
            t_lb = .false.
            last_t_lb = .false.
        else
            ! Load balance if the measure is sufficiently high (both absolute and relative
            ! to what we had after the last load balancing)
            t_lb = lt_imb > max(0.1_dp, 2 * last_imb)
            last_t_lb = t_lb
        end if
    end function need_load_balancing