[gmx-users] doubel precision

[David van der Spoel]

On Wed, 2003-08-27 at 10:58, Yuguang Mu wrote:
> Whem I compiled double precision of 3.1.4, it seems work,
> it has such printing:
> 
> Testing x86 processor CPUID...
> 
> Testing x86 SSE2 capabilities...
> No SSE2 support found for this CPU.
> 
> In this case, it is better to recompile the program switch off the
> assembly loop and enable fortran ?
> by
> --disable-x86-asm --enable-fortran

The proof of the pudding is in the eating...
If you have a good fortran compiler it will help, but g77 won't improve
on gcc code.

> 
> 
> Dr. Yuguang Mu
> Institute for Physical and Theoretical Chemistry
> J.W. Goethe University Frankfurt am Main
> Marie Curie Str. 11
> 60439 Frankfurt/Main, Germany
> Tel: +49-(0)69-798-29711
> 
> On Thu, 21 Aug 2003, Bert de Groot wrote:
> 
> > Dear all,
> >
> > we're about to renew our cluster and I'd like to share our thoughts, and
> > would very much appreciate if you could share your experience/thoughts too.
> > There have been some posts on this list about this issue, but there have
> > been some hardware developments since then, so I figured it would make sense
> > to post once again.
> >
> > So far we've been very happy with our dual athlons (apart from a few stability
> > issues), but scaling is not that great, especially with PME. We have a few nodes
> > with myrinet, but even there most jobs run on maximally 2 dual nodes
> > (4 processors), because beyond that the scaling simply breaks. We've also
> > played with gigabit ethernet and the M-VIA protocol, but these only yield
> > marginal improvements, especially on the faster nodes.
> >
> > Some points that we considered are:
> > -the latest generation of SCALI cards seem to have a quite promising
> >  price/performance ratio. Does anyone have recent experience with SCALI?
> > -what about quad Xeon boards?
> > -any alternative to scali or myrinet for improved low latency networking?
> > -can we expect developments in gromacs in the near future that will
> >  reduce the network load/improve scaling? (I don't want to push the developers
> >  here, they're doing a splendid job. It's only to optimise the planning).
> >
> >
> > cheers,
> >
> > Bert
> >
> > ____________________________________________________________________________
> > Dr. Bert de Groot
> >
> > Max Planck Institute for Biophysical Chemistry
> > Computational biomolecular dynamics group
> > Am Fassberg 11
> > 37077 Goettingen, Germany
> >
> > tel: +49-551-2011306, fax: +49-551-2011089
> >
> > email: bgroot at gwdg.de
> > http://www.mpibpc.gwdg.de/abteilungen/071/bgroot
> > ____________________________________________________________________________
> > _______________________________________________
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> >
> 
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-- 
Groeten, David.
________________________________________________________________________
Dr. David van der Spoel, 	Dept. of Cell & Mol. Biology
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://xray.bmc.uu.se/~spoel
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