With the verlet cutoff scheme (new in 4.6) you get much better control over the drift caused by (missed) short range interactions; you just set a maximum allowed target drift and the buffer will be calculated accordingly. Additionally, with the verlet scheme you are free to tweak the neighbor search frequency (nstlist) to tune for performance. As you anyway need a buffer, you should get similar if not better performance as with the default group scheme with the added benefit of and far better scalability - I.e. you'll be able to run the same system on much larger number of cores.
For more details check the manual or the following wiki page: http://www.gromacs.org/Documentation/Cut-off_schemes Cheers, -- Szilárd On Fri, May 24, 2013 at 5:13 PM, cyberjhon <cyberj...@hotmail.com> wrote: > Hi Guys > > Thanks for your reply > > 1. Ok guys I will use the following > > Double precision gromacs > > dt=1fs > pbc = xyz > > nstlist = 5 > rlist = 1.7 > rlist_long = 2.0 > > coulombtype = PME-Switch > rcoulomb_switch = 1.2 > rcoulomb = 1.4 > > fourierspacing = 0.12 > pme_order = 6 > ewald_rtol = 1e-5 > ewald_geometry = 3d > epsilon_surface = 0 > optimize_fft = yes > > vdw-type = Shift > rvdw-switch = 0 > rvdw = 1.7 > > tcoupl = no > pcoupl = no > > constraints = h-bonds > constraint-algorithm = Lincs > lincs-order = 4 > lincs-warnangle = 30 > > 2. Any other suggestion ?? > > Thanks > > John Michael > > > > > > -- > View this message in context: > http://gromacs.5086.x6.nabble.com/Have-your-ever-got-a-real-NVE-simulation-good-energy-conservation-in-gromacs-tp5008501p5008530.html > Sent from the GROMACS Users Forum mailing list archive at Nabble.com. > -- > 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 -- 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