Hackday mteodoro sky variance readnoise

[mairanteodoro]

Resolves RCAL-968

This PR adds a sky variance array to the mosaic file created by resample (i.e. model.var_sky). It also enables building a drizzle image weighted by the inverse of the sky variance when running resample with weight_type="ivsky".

Regression test

• 3 expected failing tests due to the new attribute var_sky added to the model.
• https://github.com/spacetelescope/RegressionTests/actions/runs/12265188362

Tasks

• request a review from someone specific, to avoid making the maintainers review every PR
• add a build milestone, i.e. 24Q4_B15 (use the latest build if not sure)
• Does this PR change user-facing code / API? (if not, label with no-changelog-entry-needed)
  • write news fragment(s) in changes/: echo "changed something" > changes/<PR#>.<changetype>.rst (see below for change types)
  • update or add relevant tests
  • update relevant docstrings and / or docs/ page
  • start a regression test and include a link to the running job (click here for instructions)
    • Do truth files need to be updated ("okified")?
      • after the reviewer has approved these changes, run okify_regtests to update the truth files
• if a JIRA ticket exists, make sure it is resolved properly

news fragment change types...

• changes/<PR#>.general.rst: infrastructure or miscellaneous change
• changes/<PR#>.docs.rst
• changes/<PR#>.stpipe.rst
• changes/<PR#>.associations.rst
• changes/<PR#>.scripts.rst
• changes/<PR#>.mosaic_pipeline.rst
• changes/<PR#>.patch_match.rst

steps

• changes/<PR#>.dq_init.rst
• changes/<PR#>.saturation.rst
• changes/<PR#>.refpix.rst
• changes/<PR#>.linearity.rst
• changes/<PR#>.dark_current.rst
• changes/<PR#>.jump_detection.rst
• changes/<PR#>.ramp_fitting.rst
• changes/<PR#>.assign_wcs.rst
• changes/<PR#>.flatfield.rst
• changes/<PR#>.photom.rst
• changes/<PR#>.flux.rst
• changes/<PR#>.source_detection.rst
• changes/<PR#>.tweakreg.rst
• changes/<PR#>.skymatch.rst
• changes/<PR#>.outlier_detection.rst
• changes/<PR#>.resample.rst
• changes/<PR#>.source_catalog.rst

[codecov]

Codecov Report

Attention: Patch coverage is 68.18182% with 7 lines in your changes missing coverage. Please review.

Project coverage is 77.50%. Comparing base (f538ba0) to head (af738f3).

Files with missing lines	Patch %	Lines
romancal/resample/resample_utils.py	61.11%	7 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1556      +/-   ##
==========================================
- Coverage   77.94%   77.50%   -0.44%     
==========================================
  Files         115      115              
  Lines        7622     7643      +21     
==========================================
- Hits         5941     5924      -17     
- Misses       1681     1719      +38     

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[braingram]

I follow the addition of the new weight type but I'm not sure I see the connection between the ticket and resampling each computed var_sky into a var_sky added to the mosaic model.

If the goal is to save var_sky in the mosaic model would you open a rad and roman_datamodels PRs to update the schema to include var_sky?

[schlafly]

I think this looks conceptually right; thanks! Can you put a couple of example files on /grp/roman somewhere, together with an invocation (run strun roman::resample blah.asn --weight_type skyivm ??) so that I can easily poke at some example input and output files?

[mairanteodoro]

If the goal is to save var_sky in the mosaic model would you open a rad and roman_datamodels PRs to update the schema to include var_sky?

Yes, that's the idea.