Fix silent error when running NotImplemented functions

[orionarcher]

@esoteric-ephemera couple small fixes here.

I changed return NotImplemented -> raise NotImplementedError in three locations. The former fails silently.

I also added a little more flexibility around force field names. Now users can specify force_field_name="MACE" instead of force_field_name="MLFF.MACE" or force_field_name=str(MLFF.MACE).

[esoteric-ephemera]

Hey @orionarcher, the NotImplementedError change is fine, the change to how calculators are called kinda defeats the purpose of an enum no?

[orionarcher]

Good point, I rolled back that change but am still raising an error if no calculator is found.

To leverage the Enum, maybe it'd make sense to have the type of force_field_name be MLFF rather than str? Though I imagine it's the latter to support backward compatibility.

e.g.

@dataclass
class ForceFieldRelaxMaker(AseRelaxMaker):
    """
    ...

    Parameters
    ----------
    name : str
        The job name.
    force_field_name : MLFF
        The name of the force field.
    ...

    name: str = "Force field relax"
    force_field_name: str = f"{MLFF.Forcefield}"

[esoteric-ephemera]

To leverage the Enum, maybe it'd make sense to have the type of force_field_name be MLFF rather than str? Though I imagine it's the latter to support backward compatibility.

Yeah exactly for backwards compatibility. You've raised a lot of good points about where things are inefficient / badly-schema'd in the forcefields stuff. Since this PR is intended (no guarantees) to be non-breaking and just make it easier to support general ASE stuff, why don't we open a separate atomate2 PR with a the breaking changes for ASE / forcefields? Makes it easier for everyone to discuss, and it's a good time to make breaking changes while these are still new features

[orionarcher]

Sounds good to me! I definitely don't mean to overload this PR or create more work for you.

[esoteric-ephemera]

Awesome thanks @orionarcher! As soon as this PR is merged on the atomate2 side, I'll open a new one for the breaking changes