Avoid and hide deprecation warnings

[pfebrer]

Before the next release, we:

• Hide the multiprocessing warnings (see change in metatrain.utils.logging). These just warn about a problem that has been there since forever, it's not like the new release will be less robust than the previous ones in this regard.
• Remove all uses of ModelOutput(quantity="X") to avoid getting metatomic's warning. These were useless anyway, so in principle it shouldn't be a problem. The only architecture that seems to use output.quantity is LLPR, so there I didn't change anything. But it could be that having removed it in PET will create problems. Could you see if things can be done without output.quantity @ppegolo ?
• Add unit="eV" to the ModelOutput that is initialized in metatrain.utils.data.dataset to avoid getting an "empty unit" warning.

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📚 Documentation preview 📚: https://metatrain--1248.org.readthedocs.build/en/1248/

[ppegolo]

I'll have a look at the LLPR arch, thanks

[Luthaf]

Add unit="eV" to the ModelOutput that is initialized in metatrain.utils.data.dataset to avoid getting an "empty unit" warning.

I'd rather not do that, the user should give the unit of the data in the input to avoid this warning. Guessing eV might be wrong and would be a problem …

[pfebrer]

This is just a dummy call that we do to ModelCapabilities to check that the length unit is accepted by metatomic, the output is a made up output in this case.

[pfebrer]

cscs-ci run

[pfebrer]

Thanks Paolo, your changes look good to me, so feel free to approve and merge or suggest changes if you want 👍

[pfebrer]

cscs-ci run

[pfebrer]

cscs-ci run

[pfebrer]

cscs-ci run

[pfebrer]

Ok @ppegolo I have spent some time and I don't know how to hide the "fork" warning from pytest in a clean way so I added it back to the filterwarnings list. But in principle the logs don't show the warnings anymore, could you check if this is fine in your environment in CSCS?

[pfebrer]

(in the CI it is fine, the logs don't contain the warnings)

[ppegolo]

confirmed, no fork warnings