[gmx-users] complete energy minimization

Justin A. Lemkul jalemkul at vt.edu
Wed Mar 19 11:22:11 CET 2008

Quoting s lal badshah <shahbiochemist at yahoo.com>:

> Dear experts,
> Hi! I minimized the system and gies 10,000 nsteps, but the output is:
> Steepest Descents converged to machine precision in 15 steps,
> but did not reach the requested Fmax < 1000.
> Potential Energy  = -1.9742134e+21
> Maximum force     =  4.1648520e+06 on atom 1934
> Norm of force     =  5.6557945e+06
> What other method I should adopt? or what type of correction I should do ? so
> that minimization is complete. As  before I also did this minimization and
> then in equilibration it gives faults to me. I read the errors gromacs pages
> from net but didn't reached to any conclusion. What are the other methods of
> minimization? Is it creat any problem for me in equilibration?
> Your guidance will be highly appreciated.

There is nothing wrong with this minimization output.  The process completed and
left you with a negative potential energy, which is what you're after.  What
might be more useful is a better description of what you are doing and the
"faults" that you are getting during equilibration.

What is in your system?  What force field are you using?  What is in your .mdp
file?  Providing this type of information will help us to help you.


> Regards,
> Lal badshah.
>  Send instant messages to your online friends http://uk.messenger.yahoo.com


Justin A. Lemkul
Graduate Research Assistant
Department of Biochemistry
Virginia Tech
Blacksburg, VA
jalemkul at vt.edu | (540) 231-9080


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