Adjoint test initialised from realistic increment in jelf

[tom-j-h]

PR Summary

Sci/Tech Reviewer: @mo-joshuacolclough
Code Reviewer: @mo-alistairp

A useful capability for testing robustness and performance in a realistic scenario.

• is blocked-by Align jedi_lfric_tests linear model/adjoint testing to adjoint_tests and linear_model #156
• blocks C224 adjoint tests in jelf #163
• closes jelf adjoint tests initialised with realistic increments #125

PLEASE NOTE - this is a follow-on to #156. The branch was created from #156's branch in my fork, but I can't make a PR into that branch because then I would be stuck in my fork. So, to look at the actual changes relevant to this PR alone, look at the diff of this branch with #156's branch: tom-j-h/lfric_apps@align_jedi_lfric_tests_to_linear_model...tom-j-h:lfric_apps:jelf_real_increment_adjoint_test

PLEASE ALSO NOTE - #156 relies on MetOffice/lfric_core#227, so when testing, I used this Core branch.

Code Quality Checklist

• I have performed a self-review of my own code
• My code follows the project's style guidelines
• Comments have been included that aid understanding and enhance the readability of the code
• My changes generate no new warnings
• All automated checks in the CI pipeline have completed successfully

Testing

• I have tested this change locally, using the LFRic Core rose-stem suite
• If required (e.g. API changes) I have also run the LFRic Apps test suite using this branch
• If any tests fail (rose-stem or CI) the reason is understood and acceptable (e.g. kgo changes)
• I have added tests to cover new functionality as appropriate (e.g. system tests, unit tests, etc.)
• Any new tests have been assigned an appropriate amount of compute resource and have been allocated to an appropriate testing group (i.e. the developer tests are for jobs which use a small amount of compute resource and complete in a matter of minutes)

trac.log

Test Suite Results - lfric_apps - jelf_real_increment_adjoint_test-developer/run2

Suite Information

Item	Value
Suite Name	jelf_real_increment_adjoint_test-developer/run2
Suite User	tom.hill
Workflow Start	2026-01-20T14:45:21
Groups Run	developer

Dependency	Reference	Main Like
casim	MetOffice/casim@2025.12.1	True
jules	MetOffice/jules@2025.12.1	True
lfric_apps	tom-j-h/lfric_apps@jelf_C224_adjoint_tests	False
lfric_core	tom-j-h/lfric_core@2a67d6b	True
moci	MetOffice/moci@2025.12.1	True
SimSys_Scripts	MetOffice/SimSys_Scripts@2025.12.1	True
socrates	MetOffice/socrates@2025.12.1	True
socrates-spectral	MetOffice/socrates-spectral@2025.12.1	True
ukca	MetOffice/ukca@2025.12.1	True

Task Information

✅ succeeded tasks - 1108

Security Considerations

• I have reviewed my changes for potential security issues
• Sensitive data is properly handled (if applicable)
• Authentication and authorisation are properly implemented (if applicable)

Performance Impact

• Performance of the code has been considered and, if applicable, suitable performance measurements have been conducted

AI Assistance and Attribution

• Some of the content of this change has been produced with the assistance of Generative AI tool name (e.g., Met Office Github Copilot Enterprise, Github Copilot Personal, ChatGPT GPT-4, etc) and I have followed the Simulation Systems AI policy (including attribution labels)

Documentation

• Where appropriate I have updated documentation related to this change and confirmed that it builds correctly

PSyclone Approval

• If you have edited any PSyclone-related code (e.g. PSyKAl-lite, Kernel interface, optimisation scripts, LFRic data structure code) then please contact the TCD Team

Sci/Tech Review

• I understand this area of code and the changes being added
• The proposed changes correspond to the pull request description
• Documentation is sufficient (do documentation papers need updating)
• Sufficient testing has been completed

(Please alert the code reviewer via a tag when you have approved the SR)

Code Review

• All dependencies have been resolved
• Related Issues have been properly linked and addressed
• CLA compliance has been confirmed
• Code quality standards have been met
• Tests are adequate and have passed
• Documentation is complete and accurate
• Security considerations have been addressed
• Performance impact is acceptable

[tom-j-h]

Hi Tom, I've noticed you're still merging in branches, and making commits - can I check that branch is ready for review or is the work still ongoing? Also, there appear to be some conflicts that will need resolving.

I've just noticed that this is still blocked by 156 so I presume it isn't ready for review?

Hi Alistair. The branch is ready for review, the blocking by #156 is to do with merge order. I've got a chain of PRs going (see #130) that are dependent on each other, but the changes for each can be reviewed individually. Ignore the "Files changed" above and use the diff I linked (tom-j-h/lfric_apps@align_jedi_lfric_tests_to_linear_model...tom-j-h:lfric_apps:jelf_real_increment_adjoint_test) to see the changes that are relevant for this particular PR.

There will be commits coming in to this PR any time I update PRs below it on the chain with respect to their reviews, as I then update this one. I'm doing things this way with the intent of making it easier for your team to eventually get everything onto main, since all the PRs modify the same tests.

Hope this all makes sense. If you'd rather wait for the PRs below this one on the chain to be merged to main to make it easier for you, then I have no problem with that, although my hope is to get the whole chain onto main as part of the upcoming release!

[mo-alistairp]

Thanks for clarifying that!

I've had a little look and right now these changes look fine in isolation. There isn't really a point in me testing this whilst the PRs that underpin it are changing as the tests could be voided by any change. So, I'm going to have to wait until the other PRs are at least approved, but preferably committed in order to test the changes fairly. Sorry for the inconvenience

Also, I see that this is changing Jedi-related tests - do they need to be made aware of this change?

[tom-j-h]

I've had a little look and right now these changes look fine in isolation. There isn't really a point in me testing this whilst the PRs that underpin it are changing as the tests could be voided by any change. So, I'm going to have to wait until the other PRs are at least approved, but preferably committed in order to test the changes fairly. Sorry for the inconvenience

Thanks, not an inconvenience at all.

Also, I see that this is changing Jedi-related tests - do they need to be made aware of this change?

Yes @ss421 is aware of these changes.

[mo-alistairp]

Ok, perfect - thank you! If you could let me know when the prior PRs are done and I can get straight to testing this?

[ss421]

I can confirm that this does not impact JEDI testing so there is nothing further to do on that side.