SMIRNOFF: LJPME not allowed

[mattwthompson]

It probably should be; it's supported in the biggest simulation engines, has valid scientific basis, and sees use in force fields elsewhere.

[mattwthompson]

Blocked by #15

[davidlmobley]

Re LJ-PME, we definitely want it, as there is a very strong argument for using it e.g. in binding free energy calculations. We probably want this to be called something like "lattice-sum LJ" or similar, again not specifying the exact algorithm (so avoiding the term "PME").

[mrshirts]

Yes, P3M from LAMMPS is essentially equivalent to PME LJ.

[mattwthompson]

This is probably resolved, but it'd be nice for the prose to be updated to literally include "LJPME" somewhere. When I open up the page and search for just that keyword, there are no hits.

[davidlmobley]

Yes! Looks resolved, but fully support adding the characters "LJPME" somewhere to make it searchable, maybe just as a parenthetical?