[gmx-users] different results when using different number cpus

[David van der Spoel]

Yang Ye wrote:
> 1. how long is the simulation?
> 2. did you start from equilibration (with gen_vel=yes) or production md?
> 3. ...
> 
> On 12/5/2007 8:28 PM, Dechang Li wrote:
>>  Dear all,
>> 	
>> 　　I used Gromacs3.3.1 to do a simulation about two proteins in water(tip3p).
>> I run two similar simulations, one for 2 cpus, while the other for 16 cpus.
>> The two simulations have the same .gro, .top, and the same .mdp files. I found
>> the results were not the same. In the 2 cpus simulation, the two proteins 
>> run closer and closer. But they run apart in the 16 cpus simulation.
>>    Is that normal the different results when using different number cpus? The 
>> size of my simulation box is 9*7*7.

Answer is yes.
http://wiki.gromacs.org/index.php/Reproducibility


>>
>>
>>
>>
>>
>>
>>
>> Best regards,
>>
>> 2007-12-5
>> 　　　　　　　　
>>
>> ========================================= 				
>> Dechang Li, PhD Candidate
>> Department of Engineering Mechanics
>> Tsinghua University
>> Beijing 100084
>> PR China 
>>
>> Tel:   +86-10-62773779(O) 
>> Email: li.dc06 at gmail.com
>> =========================================　　　　　
>>   
>> ------------------------------------------------------------------------
>>
>> _______________________________________________
>> gmx-users mailing list    gmx-users at gromacs.org
>> http://www.gromacs.org/mailman/listinfo/gmx-users
>> Please search the archive at http://www.gromacs.org/search before posting!
>> Please don't post (un)subscribe requests to the list. Use the 
>> www interface or send it to gmx-users-request at gromacs.org.
>> Can't post? Read http://www.gromacs.org/mailing_lists/users.php
> 
> _______________________________________________
> gmx-users mailing list    gmx-users at gromacs.org
> http://www.gromacs.org/mailman/listinfo/gmx-users
> Please search the archive at http://www.gromacs.org/search before posting!
> Please don't post (un)subscribe requests to the list. Use the 
> www interface or send it to gmx-users-request at gromacs.org.
> Can't post? Read http://www.gromacs.org/mailing_lists/users.php


-- 
David van der Spoel, Ph.D.
Molec. Biophys. group, Dept. of Cell & Molec. Biol., Uppsala University.
Box 596, 75124 Uppsala, Sweden. Phone:	+46184714205. Fax: +4618511755.
spoel at xray.bmc.uu.se	spoel at gromacs.org   http://folding.bmc.uu.se