def set_up_iter(it):
    """
    defined the time step for the first iteration and sets total simulation time at start to 0 s

    Arguments
    ---------------
        it          number of iterations

    Results
    ---------------
        dt0         first time step
        t_passed    initialize time control

    """
    iter_max = it
    dt0 = 0.01
    t_passed = 0
    return iter_max, dt0, t_passed