Adding FEniCSx solver to partitioned-heat-equation tutorial

[PhilipHildebrand]

This PR is to add a FEniCSx solver that is currently being developed at https://github.com/precice/fenicsx-adapter to the partitioned-heat-equation tutorial. We opted for a minimal working release, so parallel runs and vector-valued functions are not yet supported.

[BenjaminRodenberg]

Mostly minor cleanup work (commented out code and todos) and style. Please also make sure to update the README.md file of the tutorial case.

[BenjaminRodenberg]

The CI pipeline runs into a problem: https://github.com/precice/fenicsx-adapter/actions/runs/3761247482/jobs/6392790304#step:8:46

Can you reproduce this locally? We can also try to fix this together in our meeting tomorrow.

[BenjaminRodenberg]

The CI pipeline runs into a problem: https://github.com/precice/fenicsx-adapter/actions/runs/3761247482/jobs/6392790304#step:8:46

Can you reproduce this locally? We can also try to fix this together in our meeting tomorrow.

This was a problem introduced by some changes I introduced in PhilipHildebrand/fenicsx-adapter@038aa4f and reverted in precice/fenicsx-adapter@8c777c4. This should be fine.

[IshaanDesai]

Looka good 👍 we are almost there. Currently FEniCSx outputs xdmf and h5 files. Do you know how does one view them? Can we output VTK or VTU files? That would be the appropriate output file format if we look at other tutorials.

[PhilipHildebrand]

Looka good +1 we are almost there. Currently FEniCSx outputs xdmf and h5 files. Do you know how does one view them? Can we output VTK or VTU files? That would be the appropriate output file format if we look at other tutorials.

The XDMF files can be opened with Paraview. From what I can tell, the h5 files are a byproduct of creating the XDMF files and are pretty much irrelevant. I've tried to create VTK files, but they don't show the temperature curve at t=0 for some reason and I don't know why.

[IshaanDesai]

XDMF files can indeed be viewed in ParaView, provided the correct filer is selected. Lets keep this file format now, as it seems that FEniCSx also recommends it. @PhilipHildebrand can you resolve the conflict in the README so that we can merge this PR?