I actually have run this optimization for 150'000 steps and I have no 
explicit waters in my system...
Thanks for your proposition for using xmin but I have a problem when I 
try to run the following input file with AMBER 9:
&cntrl
imin=1, maxcyc=150000, ntmin=3,
drms=0.05, ntb=0,
cut=12.0, ntpr=100,
&end
In the output file, I have an error message:
--------------------------------------------------------------------------------
   4.  RESULTS
--------------------------------------------------------------------------------
  LMOD XMIN Minimization.
 ERROR: LMOD XMIN is unavailable.
Do you know is wrong with that??
Thanks once more
Daniel
David A. Case wrote:
> On Thu, Feb 12, 2009, Daniel Emery wrote:
>   
>> I performed a 5ns MD with sander on a system with about 30'000 atoms and  
>> no periodic conditions.
>> Everything it's fin along the dynamic.
>> After that I extract, with ptraj, the average structure of the last 50ps  
>> of the MD.
>> I try to optimize this structure and I give a drms at 0.05. But the RMS  
>> don't converge to this value. I have a minimum value at something like  
>> 0.2...
>>     
>
> You don't say how many minimization steps you used, or whether or not
> you have explicit waters.  It can take many tens of thousands of steps
> to minimize to a low rms for 30,000 atoms.  The xmin minimizer will
> generally do a better job than conjugate gradients, so you might try
> that.
>
> ...dac
>
>
> _______________________________________________
> AMBER mailing list
> AMBER.ambermd.org
> http://lists.ambermd.org/mailman/listinfo/amber
>
>   
-- 
EMERY Daniel
Ph.D. Student (Lab. R1)
Department of Organic Chemistry
University of Geneva
30, quai Ernest-Ansermet
CH-1211 Geneva 4
+41 22 379 61 55
_______________________________________________
AMBER mailing list
AMBER.ambermd.org
http://lists.ambermd.org/mailman/listinfo/amber
Received on Fri Feb 13 2009 - 01:18:54 PST