Is there a way to halt a model if it is taking too long?

Questions
3

So, in that case I have two questions I hope you could answer so I can work this out.

Could you explain the logic behind if (i > 0) and (i % 10) == 0 ?

I imagine i % 10 checks the it/sec every 10 seconds, but how does i > 0 check if the it/sec is too low?

Secondly, going over how advi (github) implements model stopping, and what needs to be accomplished in sample (github), it seems like advi does it like this:

  1. a user-defined callback raises StopIteration if too little iterations occurring,
  2. StopIteration is followed by a progress.close (lines: 83, 173, 177, 230, 250), which does not exist in pm.sample,
  3. pm.sample, however, has sampling.close, strace.close, and trace.close in many places, which I also assume roughly shuts the model down (lines: 551, 643-652, 905-915, 977-995).

So is my analysis right so far?