Small timesteps after check points in the time loop

Running some of the lecture exercises, I noticed that when simulations are run with checkpoints in the time loop, it happens that more often than not the time step sizes after the check points are quite small, because the time step size before the check point was reduced so it end at the time of the check point. The new time step after the check point may thus start with a minuscule time step size, unnecessarily increasing the number of time steps and thereby simulation time.

In DUMUX 2.12 and older versions, it was possible to use the time step size of the last "full" time step before the check point, back then called episode, to estimate the time step size when continuing after the check point. Thus, for all setups with check points in the time loop, not only the current, but also the previous time step size would need to be stored and the previous time step size would need to be used when estimating the time step size of the time step after a check point.

It might be good to reintroduce such a feature for setups / main.cc-files using check point time loops. However, since this would now need to be done in each .cc file separately, it might be a bit time consuming and repetitive, an ideal DUMUX-day or HIWI task.