OpenMM and PBCs

[sef43]

Hi just highlighting this: felixmusil/torch_nl#1 (comment)

OpenMM does not pass wrapped coordinates to the torchforce to you will need to be careful using torch_nl for the PBCs!

I have a version here that I think works with PBCs:
https://github.com/sef43/openmm-ml/tree/mace/examples/mace

[jharrymoore]

Hi Stephen, many thanks for this. We have moved away from the torch_nl neighbour list for exactly this reason, currently I have your NL implementation in my fork of openmm-ml and the default, which seems to preform pretty well, even compared to the NNPops implementation

[sef43]

great! also here is a relevant comment from over in the nequip repo: mir-group/nequip#288 (comment).
only with more than ~1000 atoms does the NNPOps implementation becomes faster than naive torchscript
And here is a notebook with the implementations: https://colab.research.google.com/drive/1Vz4QN8Y_cEUkCL2YxY86QhSruYPxfwtr?usp=sharing