@fast attribute to enable early (0-cycle) transitions between alternating dynamic/static groups

[ethanuppal]

Will eventually close #1828 once finalized and thoroughly tested (the former of which may take a while).

[ethanuppal]

I want to confirm the following: @fast in its most primitive state consists of applying the unstable early-transitions feature (which schedules 0-cycle transitions between groups g1 and g2 without regard to whether g1[done] && g2[done] is UNSAT) in an environment where we know it it is always possible (enforced via a check the well-formed pass).

[ethanuppal]

@rachitnigam @calebmkim update ping

[calebmkim]

I think this all lgtm! (As long as the problems in #662 do not apply, which I think they don't, but I haven't read the issue carefully.)

[ethanuppal]

@rachitnigam update ping

[rachitnigam]

Why does this unconditionally pass false instead of threading through early_transitions? Is it because we want to enable this if we see it in a seq or something?

[ethanuppal]

We only want to enable @fast on the parent control, I believe, unless you had different semantics in mind?

[rachitnigam]

Okay, that makes sense! We should eventually get rid of the other early-transition logic entirely in a follow-up PR.

[ethanuppal]

Hmmm, there may be more cases in which we can apply early-transition, for example, if (as @sampsyo said) one could prove that two adjacent groups cannot be done at the same time; here, we could reuse @fast's functionality, but there might be another case where it does apply recursively. That can be dealt with later though, it's not too hard to just re-add a parameter to all the functions.

[rachitnigam]

Mostly looks good! One question about the implementation and one seemingly erroneously committed file. If the file is meant to be committed, then let's document what it is meant to be doing.

[rachitnigam]

@ethanuppal can you finalize the changes and answer the questions so we can merge this PR?

[ethanuppal]

Sorry for not getting around to this sooner!jk:wq

[rachitnigam]

Awesome, thanks for implementing this! LGTM!