Subject: Tuning G98-A.9 on Power3 machines

From: Christian M�ck-Lichtenfeld <[email-masked]>
Date: Tue, 27 Jun 2000 09:14:08 +0200 (MES)

Dear Colleagues,

we have just purchased the new Gaussian98 revision (A9)
and had hoped to get some better performance on our
IBM RS6000 260 machines, compiling with XLF6.1 and XLF7.

Compiling with -O4 finishes successfully but the program
ends with an 'file operation on non-existent file' error
during the execution of testjobs. This does not occur when
the program is compiled with -O3.

We have observed that the cpu time of almost all testjobs
is independent from using either the BLAS-library from
the distribution or the ESSL-library. Maybe Gaussian98 does
not make use of subroutines like DGEMM, which is contained
in blas.F but never called from any link ? This would explain
why we do not see an effect when the library is changed,
because the library is not used in the program code. 

It would be great if someone of you who has compiled
and optimized G98 Rev A9 (or A7) under similar hardware
conditions could help us with the optimal compiler
options and configuration for a 64 bit version on a
Power3 machine.

Maybe this is not the right place for such a technical
question but Gaussian Inc. has not responded to any
such questions (by email or fax) in the past in spite
of the promised 'installation support'.

Best wishes to all,

Christian Mueck-Lichtenfeld

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Dr. Christian Mueck-Lichtenfeld
Westfaelische Wilhelms-Universitaet
Organisch-Chemisches Institut
Corrensstrasse 40
D-48149 Muenster, Germany

[email-masked]  | Tel  +49 251 83 33301
                     | Fax  +49 251 83 36515
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