[gmx-users] Who uses Gromacs on Power4 ?
baaden at smplinux.de
Wed Jun 2 12:49:36 CEST 2004
thanks for your comments. There are some pecularities which make me wonder
a bit whether it is really a problem in the actual simulation code, or rather
a typo somewhere in a more general file (makefile or so).
This is because:
- as I said same machine no problem with gmx 3.1.4, only with 3.2.1
- the error occurs at the very beginning, before even the first step
is calculated .. this is why I am a bit sceptical about the vectorized
sqrt being responsible. But it seems indeed the only part that actually
changed in fnbf.c. I will try it.
- I don't think it is a global variable problem, as gmx 3.1.4 uses the
same variable names for _buf1/_buf2 in this routine and runs fine
I'll keep on searching .. thanks for your help,
NB: I still don't know whether anybody successfully uses gmx 3.2.1 on
power3 or power4 ..
>>> Erik Lindahl said:
>> Hi Marc,
>> Power3 and Power4 are virtually identical, so this is more likely an
>> issue with a new version of the IBM compilers.
>> First, you can try and disable the vectorized sqrt with the option
>> --disable-vectorized-sqrt. I have no idea if there is any performance
>> hit or gain on power4.
>> Second, it doesn't look like a code problem. It's pretty
>> straightforward, and all variables have been initialized. We also check
>> if the pointers are null and use malloc instead of realloc in that
>> In theory there could also be global variables from the OS or compiler
>> called _buf1/_buf2, although you would probably have seen lots of error
>> messages about it. Anyway - it's a long shot, but it could be worth
>> trying to rename them to _gmxbuf1/_gmxbuf2.
Dr. Marc Baaden - Institut de Biologie Physico-Chimique, Paris
mailto:baaden at smplinux.de - http://www.marc-baaden.de
FAX: +49 697912 39550 - Tel: +33 15841 5176 ou +33 609 843217
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