Separate log statistics

[fabioseel]

Adds a class for Logging Statistics instead of using a Loss for everything to make the interface a bit more expressive:

• Loss is an extension of LogStatistics
• added keyword 'all' if a loss should just target the whole model
  • if so, the number of weights either has to match the number of circuits or be one (and then is repeated to match the number of circuits)
• added a test that runs the forward and backward pass once for the classification case and ensure that weights are being computed (nicer would be some proper test that correct weights are computed, maybe in the future)

Please double check the changes in the objectives _weighted_params function, as it's not sufficiently covered by the test 🙃

[alex404]

I don't understand actions well enough to know if this is feasible, but it might even be a good idea to have a system where it prompts the user to run a full simulation before making a merge, and provides the template command to run, i.e.

main.py +experiment=classification logging.use_wandb=True logging.wandb_project=default-master-simulations run_name={commit_hash} command=train

with the commit_hash filled out.

[fabioseel]

I don't understand actions well enough to know if this is feasible, but it might even be a good idea to have a system where it prompts the user to run a full simulation before making a merge, and provides the template command to run, i.e.

main.py +experiment=classification logging.use_wandb=True logging.wandb_project=default-master-simulations run_name={commit_hash} command=train

with the commit_hash filled out.

yeah the 'actions way' of doing this would be to run it automated... but for that we'd need a super mini example as we don't have access to a gpu at least not either free or trivially 😆
also should this cover only the classification setting?

[alex404]

Maybe we can just have a script, outside of the action setup, that fills out the command with e.g. the commit. Regardless this is a low priority item, so I'd say don't worry about it for now.

[fabioseel]

adjusted everything / added requested defaults etc, should be mergeable