[gmx-users] minimisation and constraints

Peyman Yamin Peyman.Yamin at cbi.uni-erlangen.de
Wed Jul 2 21:15:29 CEST 2008

On Wednesday 02 July 2008 20:44, Alan wrote:

Since mostly you need CG and BFGS algorithms for the cases you normally won't 
use constraints, they are not implemented to be used with constraints. 
everything should be flexible to change ==> constraint = none

steep on the other hand, though not that efficient, is good enough to be more 
often used for normal energy minimisation tasks, thus it can run with bonds 
defined as constraints. Of course one could let all flexible and steep would 
go deeper! 

see also, manual: 3.10 Energy Minimisation


> Dears,
> It's more than years that I don't use GMX on regular basis so my memory is
> leaking here.
> Is there a recommendation that once using conjugate or bfgs for
> minimisation then one have to set "constraints = all-bonds" in the mdp
> file?
> And if using steep then one have to set "constraints = none"?
> I just don't remember where I saw something like this. Any comment here
> would be very appreciate.
> Many thanks in advance,
> Alan

Peyman Yamin
Lehrstuhl fuer Thermische Verfahrenstechnik
University of Erlangen
Egerlandstr. 3, 91058 
Erlangen, Germany
peyman.yamin AT cbi.uni-erlangen.de

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