[gmx-developers] [gmx-users] Wrong Nose-Hoover integrator
lindahl at sbc.su.se
Tue Mar 29 12:46:09 CEST 2005
Sounds great, but could you possibly send us the article as an
attachement (or a reference to find it)? When I follow the link I only
get a not-logged-in message.
On Mar 29, 2005, at 12:12 PM, Berk Hess wrote:
> I have implemented the correct Nose-Hoover leap-frog scheme as written
> But I have not been able to reproduce the incorrect 3.2.1 thermostat
> as reported by Michel.
> For a box of 216 waters with delta_t=0.002 and 0.9 nm RF I get correct
> at least up to tau_t=0.1 ps.
> Michel, how many waters, what cut-off scheme and what time step did
> you use?
> The correct leap-frog algorithm (or probably any reversible
> integration scheme)
> poses another problem.
> With dt=2 fs SPC water with a full step tempature of 300 K (determined
> from v(t)),
> has a half step temperature of 297.8 K. With dt=4 fs the difference
> will be much larger.
> The full-step temperature is the more accurate expression, but can not
> be used
> in any simple integration scheme. This means that the temperature for
> simulations with reversible Nose-Hoover coupling will be off by at
> least 0.7%.
> I am afraid this problem can not be solved.
> gmx-developers mailing list
> gmx-developers at gromacs.org
> Please don't post (un)subscribe requests to the list. Use the www
> interface or send it to gmx-developers-request at gromacs.org.
-------------- next part --------------
A non-text attachment was scrubbed...
Size: 2363 bytes
Desc: not available
More information about the gromacs.org_gmx-developers