[CP2K:851] Re: g95 errors

Juerg Hutter hut... at pci.uzh.ch
Thu Mar 20 10:22:11 UTC 2008


I think you got a little bit confused here. We are talking
about 32 and 64 bit integers, not real values. Both,
cp2k and libint are using 64 bit reals as a default,
but the default integers are only 32 bit.


Juerg Hutter                   Phone : ++41 44 635 4491
Physical Chemistry Institute   FAX   : ++41 44 635 6838
University of Zurich           E-mail: hut... at pci.uzh.ch
Winterthurerstrasse 190
CH-8057 Zurich, Switzerland

On Thu, 20 Mar 2008, radsci2008 wrote:

> Concerning precision, at least GAMESS-US is all 64-bit, and must be
> modified to run on 32-bit machines, a decision made long before
> microprocessors were available at that width.  I've run across other
> codes for which this is also true, so I'm a little bit surprised that
> 32-bit precision is preferred in cp2k, but I'll take the statement at
> face value.
> Concerning g95, on i686 (default integer obligatorily 32-bit) it
> compiles (20080122 sources), implying -d4 should work on x86_64.  I
> need to go back and check whether libint will link; there may have
> been a problem but I don't have a specific recollection....
> It is, however, a good thing that libint being 32-bit was mentioned;
> this saves me barking up a wrong tree. :/  (I find little either way
> about 32 v 64 bits in the information surrounding libint....)
> Thanks again.
> >

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