[gmx-users] RE: strange mesage

Martina Bertsch, PhD mbe404 at lulu.it.northwestern.edu
Mon Mar 22 21:49:00 CET 2004

Greetings, Tanos.

VCM stands for the "velocity of the center of mass". Try running a short energy minimization (EM) before restarting your MD. If after performing EM, your position restrained MD still crashes, giving error messages such as:

"Large VCM (System)..." 

try a short PR equilibration stage without pressure scaling (coupling), i.e., modify the pr1.mdp file:

p coupling 	no

Then, in pr2.mdp re-establish the p coupling as desired.

Best regards,
Martina Bertsch, Ph.D.

tanos at ime.eb.br wrote:

> Hi folks,
> I finding the messages bellow in my mdlog.log files. The first one was:
>Large VCM (group rest):     -0.00000, -79564036107991958239722864640.00000,
>-402758638709975810048.00000, ekin-cm:          inf
>Then I started again from the point where it stopped and again the same happened:
>Large VCM (group rest):      0.00000,      3.05815,     -0.00000, ekin-cm:  3.775
>What does it means ???????
> Thanks in advance.
> Tanos Franca - IME
> Rio de Janeiro Brazil
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