Lfric fem base_mesh dependencies

[Juan Manuel Castillo Sanchez (ukmo-juan-castillo)]

PR Summary

Sci/Tech Reviewer:
Code Reviewer: mo-lucy-gordon

There are changes in the init_fem and the assign_coordinate_field subroutines to read the geometry and topology of meshes from the mesh object rather than from the base_mesh namelist. There is also a change fixing a but in the is_topology_non_periodic subroutine of the mesh object.

• linked Mesh topology bug lfric_apps#529

• closes init_fem dependencies on base_mesh #366

• fixes init_fem dependencies on base_mesh #366

Code Quality Checklist

• I have performed a self-review of my own code
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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
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Both the lfric_core and lfric_apps tests have been run, see results below.

trac.log (lfric_core)

Test Suite Results - lfric_core - lfric_fem_dependencies/run1

Suite Information

Item	Value
Suite Name	lfric_fem_dependencies/run1
Suite User	juan.m.castillo
Workflow Start	2026-05-30T15:23:56
Groups Run	all

Dependency	Reference	Main Like
lfric_core	ukmo-juan-castillo/lfric_core@lfric_fem_dependencies	False
SimSys_Scripts	MetOffice/SimSys_Scripts@cab3315	True

Task Information

✅ succeeded tasks - 402

trac.log (lfric_apps)

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Performance Impact

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AI Assistance and Attribution

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Documentation

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Sci/Tech Review

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• Sufficient testing has been completed

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

Code Review

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• Documentation is complete and accurate
• Security considerations have been addressed
• Performance impact is acceptable

[Ricky Wong (mo-rickywong)]

Don't see any reason why this can't go on, it's a subset of PR#324 which should go on, though I don't think this completely divorces init_fem from base_mesh. init_fem still wants this the prime_mesh_name I think

[Ricky Wong (mo-rickywong)]

Please can you confirm with a run at head of trunk with lfric apps that this doesn't change KGOs?

[Juan Manuel Castillo Sanchez (ukmo-juan-castillo)]

Please can you confirm with a run at head of trunk with lfric apps that this doesn't change KGOs?

I updated the trac.log in the associated lfric_apps PR. The lfric2lfric KGOs change because of the bug fix here included. Other tests do not fail because they do not use the buggy subroutine.

[Ricky Wong (mo-rickywong)]

Please can you confirm with a run at head of trunk with lfric apps that this doesn't change KGOs?

I updated the trac.log in the associated lfric_apps PR. The lfric2lfric KGOs change because of the bug fix here included. Other tests do not fail because they do not use the buggy subroutine.

It would appear that this PR and the linked Apps PR may now be duplicate. The Linked Core/Apps PRs #324 / MetOffice/lfric_apps#418 are one of the last ones to go on before vn3.2 and already contain the changes in this PR. though you should check after vn3.2 is out.

Sorry, though this PR appears to have fallen through the cracks as no milestone had been set, and the linked apps PR has only recently been changed from 528 to 529. 528 was an issue with no linked PR which is why I was asking about the whether the KGOs changed.

[Juan Manuel Castillo Sanchez (ukmo-juan-castillo)]

Duplicated - this has been addressed in #324