I am using pair_style lj/cut/coul/long with kspace_style ewald for my simulation. When I changed the precision value for the ewald sum (I've tried 1.0e-4, 1.0e-5, 1.0e-6, 1.0e-7, 1.0e-8, 1.0e-20), the magnitudes for the potential energies gets larger, and the reported values for the G vector gets larger. Is this normal/expected behavior?
I am trying to understand the relationship between the precision value and the G vector (as well as kcount, kmax, kmax3d) with what Allen&Tildesley call kappa and the number of k-vectors used in a standard Ewald calculation. I've looked over the source code a bit, but I cannot figure out exactly what's going on. For a while I thought that G vector (g_ewald) might correspond to kappa, but then I saw some lines which didn't make sense to me ...
If anyone has a explanation for how I can make these connections, I'd really appreciate it.