def fill_model(
        model, time_stop, time_step, initial_state, seed, n_points):
    """ Fill up model with output file and initial state and write it down
    in an input file

    Parameters
    ----------
    model: str
        smoldyn model description
    time_stop: Float
        Simulation duration
    time_step: Float
        Interval between two timesteps
    initial_state: [Mol]
        list of molecules at t=0
    n_points: int
        number of time samples

    """
    return model.format(
        seed=seed,
        time_stop=time_stop,
        time_step=time_step,
        freq_point=int(time_stop / (time_step * n_points)),
        initial_state="\n".join(
            [m.to_smoldyn_input() for m in initial_state]),
        )