PriorityScheduler: Update _get_filled_indices() to avoid 'block already occupied' ValueError

[michaelbaisch]

Previously, for blocks with a duration equal to the time_resolution, _get_filled_indices() was unable to identify overlapping slots. This was due to the comparison of start times not accounting for these specific cases.

This has been addressed by adjusting the start_time comparison to be slightly earlier (0.5 seconds). This change enables the correct identification of filled time slots for blocks with minimal duration, thus preventing the 'block already occupied' error.

Fixes #368

[bmorris3]

I'd bet that fixing 0.5 s is fine in most cases, but maybe not all cases. I think it would be more correct and safer to raise a warning when np.diff(start_end) <= np.min(np.diff(times)). What do you think?

[michaelbaisch]

Including such a warning is probably good. Currently, I can't imagine a scenario where both time_resolution and duration are less than 1 second, which is why I opted to simply halve it. Consider revising to something like:

filled = np.where((start_end[0]-0.05*u.second <= times) & (times < start_end[1]))

Because in general I think we should mark "as filled" on one side when equal. Given that this is likely akin to floating point comparisons, subtracting a tolerance here seems logical. The addition of "<=" may provide further clarity to our intentions.

[bmorris3]

Please also add a changelog entry.

[bmorris3]

Suggested change

	filled = np.where((start_end[0]-0.5*u.second < times) & (times < start_end[1]))
	if np.diff(start_end) <= np.min(np.diff(times)):
	warnings.warn(
	"Unexpected behavior may occur when the time "
	f"resolution ({np.min(np.diff(times))}) "
	"is not smaller than the block duration "
	f"({np.diff(start_end)}).", AstroplanWarning
	)
	filled = np.where((start_end[0]-0.5*u.second < times) & (times < start_end[1]))

If you accept this change, you'll also need to add the following import to this file:

from .exceptions import AstroplanWarning

[codecov]

Codecov Report

❌ Patch coverage is 85.71429% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 72.89%. Comparing base (a4d89a0) to head (7b015be).

Files with missing lines	Patch %	Lines
astroplan/scheduling.py	85.71%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #550      +/-   ##
==========================================
- Coverage   72.90%   72.89%   -0.02%     
==========================================
  Files          14       14              
  Lines        1849     1852       +3     
==========================================
+ Hits         1348     1350       +2     
- Misses        501      502       +1     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.