[gmx-users] Energy minimization has stopped....

[Kalyanashis Jana]

Dear Justin,
  Can you please tell me, how I can solve this problem?? If I will change
the coordinate of atom 15461, will it help me? But you know, I did this
step changing the position of drug molecule and I got same error.


On Tue, Nov 5, 2013 at 5:44 PM, Justin Lemkul <jalemkul at vt.edu> wrote:

>
>
> On 11/5/13 6:28 AM, Kalyanashis Jana wrote:
>
>> Hi,
>>    Whenever I am trying to do position retrained MD run, It has been
>> stopped
>> at middle of the MD run. I have given the following error. Can you please
>> suggest me something to resolve this error?
>> Energy minimization has stopped, but the forces havenot converged to the
>> requested precision Fmax < 100 (whichmay not be possible for your system).
>> It
>> stoppedbecause the algorithm tried to make a new step whose sizewas too
>> small, or there was no change in the energy sincelast step. Either way, we
>> regard the minimization asconverged to within the available machine
>> precision,given your starting configuration and EM parameters.
>>
>> Double precision normally gives you higher accuracy, butthis is often not
>> needed for preparing to run moleculardynamics.
>>
>> writing lowest energy coordinates.
>>
>> Steepest Descents converged to machine precision in 20514 steps,
>> but did not reach the requested Fmax < 100.
>> Potential Energy  = -9.9811250e+06
>> Maximum force     =  6.1228135e+03 on atom 15461
>> Norm of force     =  1.4393512e+01
>>
>>
> Visualize the output, specifically near atom 15461.  The forces there are
> too high and cannot be resolved further.  Any attempt to use these
> coordinates for dynamics will probably lead to a crash.
>
> -Justin
>
> --
> ==================================================
>
> Justin A. Lemkul, Ph.D.
> Postdoctoral Fellow
>
> Department of Pharmaceutical Sciences
> School of Pharmacy
> Health Sciences Facility II, Room 601
> University of Maryland, Baltimore
> 20 Penn St.
> Baltimore, MD 21201
>
> jalemkul at outerbanks.umaryland.edu | (410) 706-7441
>
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>
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-- 
Kalyanashis Jana
email: kalyan.chem.in at gmail.com