Average duration time does not affect gamma

[audunth]

In forcing.StandardForcingGenerator we have

    def get_forcing(self, times: np.ndarray, gamma: float) -> Forcing:
        total_pulses = int(max(times) * gamma)

but this implicitly assumes td=1. Properly, it should be

       total_pulses = int(max(times) / waiting_time)

As nothing stops you from setting td to something else than 1, this easily results in an error.

Some possible solutions:

• Make average duration time affect total_pulses
• Use average waiting time instead of gamma throughout
• Issue an error if average duration time is not 1 (and request the user to scale time step by the average duration time )

In my view, the cleanest solution is to use average waiting time instead of gamma: Then the arrival time generation is independent of the pulses. If you have a fancy duration time distribution, you are yourself responsible for making sure gamma is what you think it is.