[gmx-users] GROMACS compilation problem on IBM AIX

jithgmx jithgmx at indiatimes.com
Tue Feb 4 10:08:29 CET 2003


Thanks to Drs. David, Erik and Gerrit for the solutions and suggestions. I followed the suggestion by Gerrit to change the optimization level from -O3 to -O2, and it seems to be fine. I've used the IBM compiler only. 

The FFTW was compiled with pwrx (I think it is pwr2) and Gromacs with pwr4. Hope this is not a big problem with result or performance..

thanks & regards
gmx-users at gromacs.org wrote:

On Monday, Feb 3, 2003, at 09:43 US/Pacific, David van der Spoel wrote:

> On Mon, 2003-02-03 at 15:16, Gerrit Groenhof wrote:
>> Hi Jithesh,
>> I am not sure, but from your benchmark it seems gromacs is not
>> compiled properly. I had the same problem on an IBM SP3 (4?). changing
>> the optimization from O3 to O2 did the trick. What also works is to
>> change from the IBM xlc compiler to the gnu gcc compiler.
> And it is also very important to check that all libraries are compiled
> with the same options (for hardware specifics: the processor type). If
> you compile part for power3 (e.g. fftw) and part for power4 (gromacs)
> your simulations will die.
> Check an option in fftw compilation, it could be that they default for
> the wrong architecture.,

Yeah, but I think it will just default to pwr2 which should be fine 
(although not as fast).

There might indeed be a problem with the IBM compilers; if anybody can 
access to a power4 system I'll have a go at debugging it.




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