[gmx-users] timestep

[David L. Bostick]

Hello,

I have gotten the same thing before when changing from 2fs timesteps to
.1fs timesteps for 1 ps and then back to 2fs timesteps.  Everything went
nuts.. the pressure, box size, and temperature increased.  It took about
300 ps for the system to recover after switching back to 2 fs.  

David 

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David Bostick					Office: 262 Venable Hall
Dept. of Physics and Astronomy			Phone:  (919)962-0165 
Program in Molecular and Cellular Biophysics 
UNC-Chapel Hill					
CB #3255 Phillips Hall				dbostick at physics.unc.edu	
Chapel Hill, NC 27599	           		http://www.unc.edu/~dbostick	
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On Mon, 25 Mar 2002, David van der Spoel wrote:

> On Mon, 25 Mar 2002, Mehmet Suezen wrote:
> 
> >Rainer Boeckmann wrote:
> >> 
> >> ...and what about the energy? Restarting with a different timestep yields a
> >> different kinetic energy! That was the question...
> >> rainer
> >
> >then,..How would you determine suitable time step?
> If you change the timestep, you'll get a discontinuity in the trajectory, 
> and in the energies.
> 
> But you were referring to different timestep giving different temperature 
> right? Please check that other parameters (expressed in timesteps) keep 
> their same value in fs, in particular nstlist (neighbourlist update).
> 
> Maybe we should change these variables to time instead of steps...
> 
> Groeten, David.
> ________________________________________________________________________
> Dr. David van der Spoel, 	Biomedical center, Dept. of Biochemistry
> Husargatan 3, Box 576,  	75123 Uppsala, Sweden
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