Hi Erik. I was thinking something about it exactly now. I mean, Berk quoted that the scalling goes with beta/tau in Berendsen, and with beta/tay^2 in Parrinello. I mean, in a similar implementation, how should it go for a nosè implementation?
Also, what would be a good value for tau_p so? I was looking in, for exemple, the "spider tutorial", and there they use a tau_p value of .5, not so different from my value of .4 (and not .1). Finally: it also mean that if I choose a beta and tau_p pair which yelds a too low value, it won't really affect the equilibrium density of the system, correct? Thanks a lot in advance! Sincerally yours, Jones On 5/3/07, Erik Lindahl <[EMAIL PROTECTED]> wrote:
Hi, On May 3, 2007, at 12:37 PM, Jones de Andrade wrote: Hi Berk! Thanks for your so fast answer! I'll try to look for a different tau_p. I would really feel 4 ps a too high value, even for water systems, but will look around before decision. Anyway, I'm still concerned about the compressibility value. Long time ago in this list I came to this question, and this is how this ended: **>* Hi, *>* *>* Just use the water value for any liquid system (5e-5 or so). *> * *>* As the manual explains, it only affects the coupling time, not the *>* equilibrium pressure. *> This is valid for long times, and (as always for pressure) assumes the external coupling to be clearly slower than the internal dynamics. I have no idea how Amber or DLPOLY sets their tau_t with Nose or Parinello-Rahman, but as specified in the Gromacs manual we use the period of average fluctuations at equilibrium. With tau=0.1 the system will very likely never reach that equilibrium. Cheers, Erik _______________________________________________ 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
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