Stopping solver once condition is met

[francescabasini]

Dear Dr. Zwicker,

Thank you for the extremely useful package.

I wonder if there exists a way to have a tracker that checks for a condition on the system's state and stops the iterations while saving the latest result.
For now I was able to use DataTracker to compute the quantity of interest (a float) at a fixed interval but the solver runs until t_range = t_max.
I'd very much appreciate an input on this.

[david-zwicker]

Your best bet might be using a CallbackTracker, which calls a user-defined function. This function can of course store data wherever you want it to be, but it can also raise a StopIteration exception, which will abort the simulation cleanly.