JP-3242: Proper Handling of Timing for Final Slope Computation for only 0th Good Group Ramps

[kmacdonald-stsci]

Resolves JP-3242

This PR addresses special handling of timing for ramps that have only good 0th group in a ramp. The addition of this special case only properly computed the variances. The timing division for the final slope computation still used the group time, which is not correct for certain special cases. All timing divisions have been pushed back to the segment calculations, so there is no longer one final divide. There is also the further subset special case for only 0th good group with the use of ZEROFRAME.

These corrections have been made in STCAL, which affects the CI tests in JWST. The ramp fitting CI tests have been updated. The STCAL PR spacetelescope/stcal#173 needs to be merged first before this PR.

Checklist for maintainers

• added entry in CHANGES.rst within the relevant release section
• updated or added relevant tests
• updated relevant documentation
• added relevant milestone
• added relevant label(s)
• ran regression tests, post a link to the Jenkins job below.
  How to run regression tests on a PR
• Make sure the JIRA ticket is resolved properly

[hbushouse]

Started regtest, using stcal/main, at https://plwishmaster.stsci.edu:8081/job/RT/job/JWST-Developers-Pull-Requests/754/

[hbushouse]

regtest run showed mostly unrelated differences, except for 1 ramp_fit unit test that's also failing in the CI runs. "No module named 'general_funcs'"

[codecov]

Codecov Report

Patch coverage has no change and project coverage change: -0.83 ⚠️

Comparison is base (6db53ff) 77.43% compared to head (4d5fd22) 76.61%.

❗ Current head 4d5fd22 differs from pull request most recent head 34d5172. Consider uploading reports for the commit 34d5172 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #7612      +/-   ##
==========================================
- Coverage   77.43%   76.61%   -0.83%     
==========================================
  Files         451      456       +5     
  Lines       35702    36819    +1117     
==========================================
+ Hits        27647    28209     +562     
- Misses       8055     8610     +555     

Flag	Coverage Δ		*Carryforward flag
nightly	77.43% <ø> (ø)		Carriedforward from 88ed717

*This pull request uses carry forward flags. Click here to find out more.

see 76 files with indirect coverage changes

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[hbushouse]

Looks to me like all the CI failures are due to the use of stcal==1.3.8, so it isn't picking changes from the PR recently merged to stcal/main. Guess we need an stcal release to fix that situation. Although a regtest run making use of stcal/main should get around that.

[hbushouse]

Another regtest run started at https://plwishmaster.stsci.edu:8081/job/RT/job/JWST-Developers-Pull-Requests/757 using stcal/main.

[kmacdonald-stsci]

Looks to me like all the CI failures are due to the use of stcal==1.3.8, so it isn't picking changes from the PR recently merged to stcal/main. Guess we need an stcal release to fix that situation. Although a regtest run making use of stcal/main should get around that.

I ran the ramp fitting tests locally using the latest STCAL main and they passed.

[hbushouse]

Still has a code style failure for the opedal variable in the unit tests.

[hbushouse]

Latest regtest run shows only a few unrelated differences. Looks good.

[hbushouse]

Everything looks good now, except of course for the CI tests that won't pass because they're using the released version of stcal, rather than stcal/main. All tests pass in the regtest environment when build with stcal/main.