[gmx-users] ISO-8859-1?Q? fixed=3F?=

Steve Cousins cousins at umit.maine.edu
Thu Sep 17 20:06:29 CEST 2009

On Thu, 17 Sep 2009, Discussion list for GROMACS users wrote:

>>> Since there is a 10% speedup by going back to version 3.3, is there any
>>> reason *not* to use 3.3 instead on the Altix? I'm sure there are other
>>> bug fixes and features since then but I don't know much about MD so I
>>> don't know how important they are. I'm just getting it to run on our
>>> machine so the chemists can run the code.
> Scaling is much better in 4.0.x. If you use more than 8 cores that
> should compensate for the loss in single precision performance.

That's good to know. That's why we want to put it on this machine (to use 
more than 8 cores).

> In addition there are other new features and bug fixes of course.
>>> Since the optimizations worked in 3.3, it *seems* like it might not be
>>> too bad to get them to work with the new version. Probably 4.0 was a
>>> major re-write though. Are there any plans for fixing the IA64
>>> optimizations?
> Don't know, it must be something trivial I assume, but it is quite
> specialist work.

I agree. Could possibly be a black hole of time spent on debugging, all 
for a processor that is dead but still kicking.

Thanks for the insight David and Carsten.

  Steve Cousins - Supercomputer Engineer/Administrator - Univ of Maine
  Marine Sciences, 452 Aubert Hall       Target Tech, 20 Godfrey Drive
  Orono, ME 04469    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~     Orono, ME 04473
  (207) 581-4302     ~ cousins at umit.maine.edu ~      (207) 866-6552

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