Hi Mark and Florian, Thank you kindly!
My colleagues and I are actually using going to use the plain Ewald method in Gromacs. We have a slab geometry and two capacitor plates. In all cases we use the Berkowitz dipole correction (ewald_geometry = 3dc) to obtain pseudo 2-D summation. We have tried both PME and plain Ewald methods. Strangely, when we use PME, we observe a large drift in the electric potential (which we calculate using g_potential) between the capacitor plates. When, however, we use the plain Ewald method, we do not observe the drift in the electric potential between the plates; the potential is fairly flat. We have tried for several weeks to play with the PME parameters, but no matter what PME parameters we use, the drift in the electric potential persists. When we use the plain Ewald method, however, the electric potential is always flat, consistant with the results from another MD package. Do you have any experience with significant differences between PME and Ewald results? It certainly seems from reading the mailing list archives that there is really never any disadvantage to using PME. In fact, I read that Dr. Lindahl said that this is why the plain Ewald has never been implemented in parallel; it just would not be worth the development effort. PME is so much faster, that there is really never any reason to use anything else. So my colleagues are just stumped by how the PME and Ewald results could be so much different for us. Thank You! Andrew DeYoung Carnegie Mellon University > The former for PME. The latter for plain Ewald (which you should > probably not want to use). > > Mark -- gmx-users mailing list gmx-users@gromacs.org http://lists.gromacs.org/mailman/listinfo/gmx-users Please search the archive at http://www.gromacs.org/Support/Mailing_Lists/Search before posting! Please don't post (un)subscribe requests to the list. Use the www interface or send it to gmx-users-requ...@gromacs.org. Can't post? Read http://www.gromacs.org/Support/Mailing_Lists
