[gmx-users] floating point exception for grompp -e ener.edr on some clusters

[David van der Spoel]

chris.neale at utoronto.ca wrote:
>>> I have attempted the CFLAGS=-g (full output at end of email). The 
>>> error message is now:
>>>
>>> Program received signal SIGFPE, Arithmetic exception.
>>> 0x12001449c in do_enx (fp=0, fr=0x12010a9c0) at enxio.c:310
>>> 310     enxio.c: No such file or directory.
>>>         in enxio.c
>>
>> Try adding the following in enxio.c at line 305:
>>
>>     for(i=fr->e_alloc; (i<fr->nre); i++) {
>>       fr->ener[i].e = fr->ener[i].eav =
>>     fr->ener[i].esum = fr->ener[i].esum2 = 0;
>>     }
>>
>> The code should come *in-between* the following two lines:
>>
>>     srenew(fr->ener,fr->nre);
>>     fr->e_alloc = fr->nre;
>>
>> Alphas are very sensitive about not-initialized variables.
> 
> Excellent. Your suggestion has resolved the problem. Thank you very much 
> for your assistance. I would never have been able to figure this out 
> myself. Please note that actually I used these lines:
> 
>      for(i=fr->e_alloc; (i<fr->nre); i++) {
>        fr->ener[i].e = fr->ener[i].eav =
>     fr->ener[i].esum = fr->ener[i].e2sum = 0;
>      }
> 
> where e2sum is used in place of esum2 for gromacs 3.3.1 and 3.3.2
Great,

I've committed this to CVS now, should be in the coming 3.3.3 release.

-- 
David.
________________________________________________________________________
David van der Spoel, PhD, Assoc. Prof., Molecular Biophysics group,
Dept. of Cell and Molecular Biology, Uppsala University.
Husargatan 3, Box 596,  	75124 Uppsala, Sweden
phone:	46 18 471 4205		fax: 46 18 511 755
spoel at xray.bmc.uu.se	spoel at gromacs.org   http://folding.bmc.uu.se
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