Add missing λ-factor in force and potential for LennardJonesSoftCoreBeutler

[Immi000]

This adds the missing lambda-factor referred to here.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 68.62%. Comparing base (0bd1d62) to head (3ea323b).
⚠️ Report is 6 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #232   +/-   ##
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  Coverage   68.61%   68.62%           
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  Files          46       46           
  Lines        9120     9121    +1     
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+ Hits         6258     6259    +1     
  Misses       2862     2862           

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[jgreener64]

Thanks for this. Would you mind updating the docstring and making the analogous changes for CoulombSoftCoreBeutler too?

I guess the Gapsys soft core variants should also have this change?

[Immi000]

I added the missing λ to CoulombSoftCoreBeutler as well and updated the CoulombSoftCoreBeutler and LennardJonesSoftCoreBeutler docstrings correspondingly.

As far as I can tell the Gapsys formulation depends on λ only implicitly via the switching radius which seems to be implemented correctly, so I think no adjustment is necessary there.

[jgreener64]

Thanks for the changes. Having a look it seems that OpenFE also applies the same λ weighting to the Gapsys variants (https://github.com/OpenFreeEnergy/openfe/blob/013b4b3213b8329339607296d371df8b8e207b92/openfe/protocols/openmm_rfe/_rfe_utils/relative.py#L810), so I think those should change as well.

[Immi000]

Right, that makes sense, I seem to have looked at the single state formula instead of the full interpolation. I've adjusted the Gapsys LJ and Coulomb force and potential.

[jgreener64]

Great, thanks.