Gauss-Legendre DGSEM Solver: 2D P4estMesh periodic

[DanielDoehring]

Convergence test advection:

####################################################################################################
l2
scalar              
error     EOC       
5.76e-05  -         
3.72e-06  3.95      
2.24e-07  4.06      
1.40e-08  4.00      
8.71e-10  4.01      

mean      4.00      
----------------------------------------------------------------------------------------------------
linf
scalar              
error     EOC       
2.99e-04  -         
1.86e-05  4.01      
1.05e-06  4.14      
7.03e-08  3.91      
4.35e-09  4.01      

mean      4.02      
----------------------------------------------------------------------------------------------------

xref #2826

[github-actions]

Review checklist

This checklist is meant to assist creators of PRs (to let them know what reviewers will typically look for) and reviewers (to guide them in a structured review process). Items do not need to be checked explicitly for a PR to be eligible for merging.

Purpose and scope

• The PR has a single goal that is clear from the PR title and/or description.
• All code changes represent a single set of modifications that logically belong together.
• No more than 500 lines of code are changed or there is no obvious way to split the PR into multiple PRs.

Code quality

• The code can be understood easily.
• Newly introduced names for variables etc. are self-descriptive and consistent with existing naming conventions.
• There are no redundancies that can be removed by simple modularization/refactoring.
• There are no leftover debug statements or commented code sections.
• The code adheres to our conventions and style guide, and to the Julia guidelines.

Documentation

• New functions and types are documented with a docstring or top-level comment.
• Relevant publications are referenced in docstrings (see example for formatting).
• Inline comments are used to document longer or unusual code sections.
• Comments describe intent ("why?") and not just functionality ("what?").
• If the PR introduces a significant change or new feature, it is documented in NEWS.md with its PR number.

Testing

• The PR passes all tests.
• New or modified lines of code are covered by tests.
• New or modified tests run in less then 10 seconds.

Performance

• There are no type instabilities or memory allocations in performance-critical parts.
• If the PR intent is to improve performance, before/after time measurements are posted in the PR.

Verification

• The correctness of the code was verified using appropriate tests.
• If new equations/methods are added, a convergence test has been run and the results
  are posted in the PR.

Created with ❤️ by the Trixi.jl community.

[codecov]

Codecov Report

❌ Patch coverage is 95.79439% with 9 lines in your changes missing coverage. Please review.
✅ Project coverage is 97.07%. Comparing base (16e465f) to head (40acf2b).
⚠️ Report is 6 commits behind head on main.

Files with missing lines	Patch %	Lines
src/solvers/dgsem_p4est/dg_2d.jl	95.93%	5 Missing ⚠️
src/solvers/dgsem_p4est/containers.jl	88.89%	3 Missing ⚠️
src/meshes/p4est_mesh_view.jl	50.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2847      +/-   ##
==========================================
- Coverage   97.08%   97.07%   -0.00%     
==========================================
  Files         611      612       +1     
  Lines       47580    47777     +197     
==========================================
+ Hits        46189    46379     +190     
- Misses       1391     1398       +7     

Flag	Coverage Δ
unittests	97.07% <95.79%> (-<0.01%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ 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.

[DanielDoehring]

I realized I also need to compute & store now the normals at interfaces:

Trixi.jl/src/solvers/dgsem_p4est/dg_2d.jl

Lines 166 to 170 in 18a6ac7

	normal_direction = get_normal_direction(primary_direction,
	contravariant_vectors,
	i_primary, j_primary,
	primary_element)

which cannot be inferred from the elements only. The reason why the current example works is that the mesh is effectively cartesian.

[DanielDoehring]

Please ping us (Andrew, me; maybe on Slack) when you would like to get a review.

This will take some time, I need to check the GPU changes and adapt this PR. This is started with #2899

[ranocha]

Thanks

[JoshuaLampert]

Thanks! I only have one question below.