[gmx-users] question to mdp file

[Justin A. Lemkul]

On 7/3/12 8:25 AM, reisingere at rostlab.informatik.tu-muenchen.de wrote:
> Ah okey. Yes sorry that was a typo...I ment nsteps.
> So but is there a possibility to define a minimal step size so that the
> minimization ends when the energy does not changes much any more?
>

Just set emtol to some unreasonably low value, and mdrun will end with this 
message (which is not really an error):

http://www.gromacs.org/Documentation/Errors#Stepsize_too_small.2c_or_no_change_in_energy._Converged_to_machine_precision.2c_but_not_to_the_requested_precision

You can set emstep to whatever size you like to reach this point.

-Justin

>>
>>
>> On 7/3/12 8:11 AM, reisingere at rostlab.informatik.tu-muenchen.de wrote:
>>> Hi everybody,
>>> is it correct when I set the
>>> nstep = -1  and
>>> emtol = $number
>>>
>>> that the minimization goes as long as the energy difference between the
>>> previous step and this step is not lower as $number. And that there is
>>> no
>>> maximal stepsize?
>>>
>>
>> No.  The value of emtol is the target for the maximum force to define
>> convergence, not the difference between previous and current steps, and
>> it's not
>> an energy term, it's force.  The maximum step size is always set in
>> emstep.
>> What's more, "nstep" is not a correct keyword, but "nsteps" is.
>>
>> -Justin
>>
>> --
>> ========================================
>>
>> Justin A. Lemkul, Ph.D.
>> Research Scientist
>> Department of Biochemistry
>> Virginia Tech
>> Blacksburg, VA
>> jalemkul[at]vt.edu | (540) 231-9080
>> http://www.bevanlab.biochem.vt.edu/Pages/Personal/justin
>>
>> ========================================
>>
>>
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>
>
>

-- 
========================================

Justin A. Lemkul, Ph.D.
Research Scientist
Department of Biochemistry
Virginia Tech
Blacksburg, VA
jalemkul[at]vt.edu | (540) 231-9080
http://www.bevanlab.biochem.vt.edu/Pages/Personal/justin

========================================