Plot fv 2d for issue #2998

[MagalieHeinrich]

Marius Nickels (https://github.com/nickki-m) and I worked on issue #2998: "Improve plotting for 2D/3D simulations with polydeg = 0 on the TreeMesh (finite volume case)". With our additions the test example given in issue #2998 shows no red bars any more.

I used an AI assistant to help me get through some Git remote issues regarding the branch publishing/upload process.
I dont know whats wrong with Project.toml. I didnt touch it.

[github-actions]

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Created with ❤️ by the Trixi.jl community.

[ranocha]

Please clean up the code as discussed offline.

[MagalieHeinrich]

@ranocha I've added the requested comments and removed the debug command.

[ranocha]

This is the first round of review comments to show you the next steps in class.

[ranocha]

Did you check whether it works correctly for polydeg = 0 and polydeg > 0 also for locally refined meshes?

[ranocha]

This is problematic since this check will also be true for the standard DG case.

[MagalieHeinrich]

I unpack the solver in the first line where things are unpacked (unpack plot_data, variable_id, solver =pds).
I then use it in the if loop (if nnodes(solver)==1 && the things that were there before).
This works with the example from the issue.

[ranocha]

To check the current behavior for DG methods, you can use code along the lines of

(@v1.10) pkg> activate --temp

(jl_kge4bE) pkg> add Trixi OrdinaryDiffEqLowStorageRK Plots

julia> using Trixi, Plots

julia> trixi_include(joinpath(examples_dir(), "tree_2d_dgsem", "elixir_advection_basic.jl"), initial_refinement_level = 1); plot(sol)

and run the same commands except the package manager code on your branch for this PR to compare the results.

[MagalieHeinrich]

I tested with
"(@v1.10) pkg> activate --temp

(jl_kge4bE) pkg> add Trixi OrdinaryDiffEqLowStorageRK Plots

julia> using Trixi, Plots

julia> trixi_include(joinpath(examples_dir(), "tree_2d_dgsem", "elixir_advection_basic.jl"), initial_refinement_level = 1); plot(sol)"

and it didnt throw an error.

[DanielDoehring]

What is this --> operator? I could only find documentation for the -> operator

https://docs.julialang.org/en/v1/base/base/#-%3E

[JoshuaLampert]

It is special for plot recipes for Plots.jl, see https://docs.juliaplots.org/stable/RecipesBase/syntax/.

[MagalieHeinrich]

Hi @ranocha, I have removed the length checks in recipes_plots.jl. They are not necessary. I verified that both the FV (from the issue description) and DG (the one you sent me) examples are plotting correctly. The DG example works in Julia version 11 (not only in version 10 like a had thought last week).

[codecov]

Codecov Report

❌ Patch coverage is 16.00000% with 42 lines in your changes missing coverage. Please review.
✅ Project coverage is 96.76%. Comparing base (80dc6c5) to head (14e5595).
⚠️ Report is 20 commits behind head on main.

Files with missing lines	Patch %	Lines
src/visualization/recipes_plots.jl	12.50%	14 Missing ⚠️
src/visualization/types.jl	12.50%	14 Missing ⚠️
src/visualization/utilities.jl	6.67%	14 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3033      +/-   ##
==========================================
- Coverage   96.92%   96.76%   -0.16%     
==========================================
  Files         635      637       +2     
  Lines       49338    49624     +286     
==========================================
+ Hits        47818    48016     +198     
- Misses       1520     1608      +88     

Flag	Coverage Δ
unittests	96.76% <16.00%> (-0.16%)	⬇️

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