On Thu, 2008-08-21 at 10:32 -0400, Sumanth Jamadagni wrote: > Using a negative 'dt' in the mdp file does not not seem to cause any > simulation problems (tested on a waterbox- doesn't crash). I am not sure > if the system is evolving backwards in time though. I am not sure how to > check that.
So is the purpose of this to run an NVE simulation? Since if you have any thermostats enabled the sign of the time step doesn't matter since the simulation is "screwed up" anyhow.. Also when using thermostats inverting the sign of the time step may cause wrong behaviour since then the difference to the desired value may increase if the time step is assumed positive in the algorithm. Physically, inverting the initial velocity corresponds to inverting the direction of time. Of course you will not get back the same configurations as before due to rounding errors and a chaotic system. -- ------------------------------------------------------ Jussi Lehtola, FM, Tohtorikoulutettava Fysiikan laitos, Helsingin Yliopisto [EMAIL PROTECTED], p. 191 50673 ------------------------------------------------------ Mr. Jussi Lehtola, M. Sc., Doctoral Student Department of Physics, University of Helsinki, Finland [EMAIL PROTECTED] ------------------------------------------------------ _______________________________________________ gmx-users mailing list gmx-users@gromacs.org 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
