Suboptimal az path is chosen in some cases

[mhasself]

The function recur is intended to find the best az values (taking into account branch options and sun avoidance) at which to run each operation.

I suspect this function isn't implemented correctly. The example in https://github.com/simonsobs/scheduler/issues/73 shows one consequence of the implementation -- the scheduler injects a move_to(az=52.0) unnecessarily; I think it could have just stayed at az=218 (or so) to do the bias_step. This happens because of some interaction with sun avoidance -- but I am finding it difficult to tell what the purpose of the function is, precisely.

I hereby request, for this specific az path optimization:

• unit tests (including a test that exposes the failure observed in #73, before it gets solved)
• clearer docstrings that state what the purpose of the function is (i.e. the problem it is solving / the metric it is using to optimize) and thus what the criteria for a successful test would be

[guanyilun]

Should I close this now since recur is superseded by a better implementation from @mhasself? I understand the need of better unit tests, which could be tracked in a separate issue under a better name.

[mhasself]

Fine with me but consider just putting in a few unit tests, and establishing that framework, and then you could close this issue without having to make a new one! $$$