Make save function more universal to accept any number of 1D or 2D node or edge features

[maxiimilian]

Describe your changes

This pull request contains three changes -- one major and two minor changes.

The major change modifies how edge and node features are converted from pyg.data.Data objects into torch.Tensors before saving. If we assume that all node/edge features (features in the following) are numeric, a conversion to float32 will always work. Further, my proposed change assumes that the features can be either 1D (vector of edge lengths) or 2D (node position, vdiff vector between source and target nodes). Based on this, I propose a universal function that reshapes any 1D vector into a 2D column vector, which allows the concatenation of any number of features in a loop.

Using the new function, we also make the saving of len as edge feature explicit by including it in the default edge_features list.

Two minor bugs are fixed:

• Default arguments of functions should not be mutables (list, dicts, any object). See https://docs.python-guide.org/writing/gotchas/#mutable-default-arguments.
• The hide_ticks argument for nx.draw seems to be deprecated because it caused an error with my networkx v 3.2

Type of change

• 🐛 Bug fix (non-breaking change that fixes an issue)
• ✨ New feature (non-breaking change that adds functionality)
• 💥 Breaking change (fix or feature that would cause existing functionality to not work as expected)
• 📖 Documentation (Addition or improvements to documentation)

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[joeloskarsson]

This is great, thanks a lot for this contribution! 😄

I went over the code and left some small comments. I don't think there is any need for adding additional tests here as

1. the saving functionality with default feature arguments is already tested in

   weather-model-graphs/tests/test_save.py

   Line 18 in 2456064

   def test_save_to_pyg():

2. we don't have any good functionality to add additional edge/node features that is now saveable with this more universal approach and could be used in a test (as far as I remember, let me know if I am wrong)

There are a couple small additional things that would be good to do before merging this:

1. The linting seems to fail due to the code formatting. This should be easily fixed by just running the pre-commit hooks once.
2. Go ahead and add an entry to the changelog! 🙂

[joeloskarsson]

Tests and linting are all green now 🥳 Just want a small tweak to keep the formatting of the changelog consistent, then this is good to merge!

[joeloskarsson]

Everything good now, I'll merge this in. Thanks again for this contribution!