On Tue, 2009-03-10 at 09:46 +0000, GuoGuangjun wrote: > Hi, > > According to Berk's instructions, I first run a 5 ns-long berendesen > P-coupling simulation, and then change to Parrinello-Rahman coupling > for another 5 ns. The parameters and results are listed in the > following. My question is why the average pressures in the X- and > Y-directions is not equal to the expected pressure. > tau_p = 10
Your runtime is one half of the pressure relaxation time. I'd say you need to run for a much longer time than that. Also, the deviation compared to the fluctuations is small: 57 bar / 121 bar ~ 0.47 < 0.5 sigma. In x and y directions the deviation is even smaller: 85/201 ~ 0.42 -- ------------------------------------------------------ Jussi Lehtola, FM, Tohtorikoulutettava Fysiikan laitos, Helsingin Yliopisto [email protected], p. 191 50632 ------------------------------------------------------ Mr. Jussi Lehtola, M. Sc., Doctoral Student Department of Physics, University of Helsinki, Finland [email protected] ------------------------------------------------------ _______________________________________________ gmx-users mailing list [email protected] http://www.gromacs.org/mailman/listinfo/gmx-users Please search the archive at http://www.gromacs.org/search before posting! Please don't post (un)subscribe requests to the list. Use the www interface or send it to [email protected]. Can't post? Read http://www.gromacs.org/mailing_lists/users.php
