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brucefan1983 / NEP_CPU

CPU version of NEP
GNU General Public License v3.0
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[Q] neigh_modify exclude #19

Closed chem-william closed 1 year ago

chem-william commented 1 year ago

I'm not sure whether I'm misunderstanding the physics or NEP, but I get very different results when I exclude a frozen group of atoms using neigh_modify exclude group SOLID SOLID where SOLID refers to a group of atoms that is not time-integrated and have had their forces set to 0.0 0.0 0.0

Is it expected that NEP works with excluding groups of atoms?

brucefan1983 commented 1 year ago

I am not clear what's the possible cause as I am not quite familiar with LAMMPS. Do you know exactly what this command does? If the neighbor list is modified, many-body potential such as NEP can have very different results. It will be like some atoms are removed and the descriptors of some atoms will be changed.

chem-william commented 1 year ago

Fair enough. According to the documentation it turns off the pairwise interaction between atoms if one atom is in one group and the other atom is in the other group. It 'turns off interaction' by excluding them from the neighbor list.

So I guess, with NEP being a many-body potential, tampering with the neighbor list is not a good idea (at least not in this way)

Thank you for response!