Ah, now perhaps I see that I misread the question - it could have been phrased more clearly. If Erik understood it correctly, then the answer to the question is: It depends on the integrator. The simulation is not constrained to a particular temperature or pressure - rather, the dynamics are modified such that the ensemble is consistent with the external temperature and pressure are specified. Exactly where in the integration routine the dynamics are modified depends on the method used. See the manual for more of the details!
On Thu, Feb 7, 2013 at 3:59 AM, Erik Marklund <er...@xray.bmc.uu.se> wrote: > Hi, > > Perhaps a side point: Temperature and pressure can not be seen as > constraints to the system at any given instant in the sense that e.g. the > instantaneous kinetic energy perfectly match the temperature at every time > step just because you have a thermostat. Time and ensemble averages will, > however, reflect the temperature and pressure coupling. > > Erik > > > On Feb 6, 2013, at 11:28 PM, Bao Kai wrote: > >> Dear Gromacs Team, >> >> I have a small question related to the scheme of the MD in Gromacs. >> >> When are the temperature and pressure constrains are enforced, before >> the update of the velocity and position or after? >> >> Thank you very much. >> >> Best Regards, >> Kai >> -- >> 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 thewww 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
