Fix unweighted EnergyForcesLoss

[chaitjo]

This PR fixes unweighted EnergyForcesLoss.

This is a trivial fix - it seems that the code for WeightedEnergyForcesLoss was copied for the unweighted default variant, EnergyForcesLoss.

Currently, EnergyForcesLoss is being used as a default fallback here:

mace/scripts/run_train.py

Line 180 in 44b6da4

else:

[davkovacs]

Thanks for spotting this! I would say we don't need a separate class for this case. How about just initialising the weighted one with weights being 1.0 ?

[chaitjo]

I updated the loss modules.

An alternative formulation from the current one in the PR could be to get rid of the EnergyForcesLoss class altogether, and initialise the default setting in run_train using the WeighterEnergyForcesLoss with 1.0/1.0 weights.

[ilyes319]

I think that's the best, to remove it altogether

[chaitjo]

Done

[davkovacs]

I think it is ready to merge