avFFunc Function

    function avFFunc(DetSgn, DetPosition) result(AvFmu)
        ! get fmu
        use procedure_pointers, only: shiftFactorFunction
        implicit none
        real(dp), intent(in) :: DetSgn(lenof_sign)
        integer, intent(in) :: DetPosition
        real(dp) :: AvFmu

        integer :: run
        real(dp) :: fmu

        AvFmu = 1.0_dp
        do run = 1, inum_runs
            fmu = shiftFactorFunction(DetPosition, run, mag_of_run(DetSgn, run))
            AvFmu = AvFmu * fmu
        end do
        AvFmu = dressedFactor(AvFmu**(1.0_dp / real(inum_runs, dp)))
    end function avFFunc