Enable save_solution and Trixi2Vtk for DGMultiMesh

[Davknapp]

Currently, there is no DGMultiMesh-support for the save_solution function. It would be very convenient to save DGMultiMeshes in an HDF5 format and translate them via Trixi2VTK into a vtk-file, such as for quad-meshes for example.

[sloede]

I think this would be a very nice feature to have. Especially since the analysis capabilities with Makie.jl (especially for 3D solutions) can sometimes be less convenient than with something like ParaView.

There are two steps to this:

• Adapt the SaveSolutionCallback to work with the DGMulti solver.
• Adapt Trixi2Vtk.jl to work with triangular meshes. The main routine is trixi2vtk. Here, the most important parts are going to be the call to read_datafile, build_vtk_grids, and finally interpolate_data. The rest might "just work".

If you need help with anything, please let us know!

[Davknapp]

Thank you for the guideline! I am currently working on the adaptation of the SaveSolutionCallback. Shall I open a draft as soon as I get first results? Then, I would switch over to Trixi2VTK to translate the HDF5-files.

[ranocha]

Yes, please :+1:

[Davknapp]

My current developments can be found in draft #1201 . I got some difficulties to

• extract the vertices in a format suitable for the hdf5 format
• transform u such that it can be stored in 'file["variables_$v"]

I think I need some advanced "Julia-magic" here, I would be happy about some hints ;)