I think the same way as you. They do bring in errors but this is acceptable in normal MD because we already have lots of approximations. BTW, -sum has been dropped from 4.5, in other words, Gromacs won't calculate global Energy every step by default now.
dawei On Fri, Dec 14, 2012 at 9:46 AM, Thomas Schlesier <schl...@uni-mainz.de>wrote: > Dear all, > i have a small question regarding the '-nosum' option of 'mdrun'. > The manual states: > > For a global thermostat and/or barostat the temperature and/or pressure > will also only be updated every nstlist steps. With this option the energy > file will not contain averages and fluctuations over all integration steps. > > Second sentence is clear to me. But the first sentence give me some > thoughts. > I think this would introduce some errors, but what is about the magnitude > of these? > I would expected that the errors are in the same order of the errors in > the forces due to the neighborlist search (error due to the fact that one > uses 'nstlist=5' instead of 'nstlist=1') and would be more or less > negilegible, if one doesn't use a very larger 'nstlist'-value. > > But to be on the save side i wanted to ask. > > Greetings > Thomas > -- > gmx-users mailing list gmx-users@gromacs.org > http://lists.gromacs.org/**mailman/listinfo/gmx-users<http://lists.gromacs.org/mailman/listinfo/gmx-users> > * Please search the archive at http://www.gromacs.org/** > Support/Mailing_Lists/Search<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<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
