Subject: Re: CCL:Installation of g98 Rev A7

From: Joe Ochterski <[email-masked]>
Date: Thu, 14 Oct 1999 16:28:49 -0400

On Thu, Oct 14, 1999 at 04:18:10PM +0200, Bernd Melchers wrote:
> 'Jens Antony wrote:'
> > 
> > Dear all!
> > 
> > We are installing the new version of Gaussian98 on an SGI R10000. The
> > compilation finishes without obvious error messages. When executing the
> > program, however, it stops without reading the input and writes a core
> 
> You need a Makefile suitable for your compiler version.
> Our gaussian98 A6 generates core dumps with compiler versions 7.3.1 (IRIX 6.5.5)
> but not with compiler 7.2.x. There is a new Makefile available from
> gaussian for 7.3.0 Compilers but it produces code which is
> 30 % slower. And occasionally dumps core, also.
> It seems, the people at gaussian have to do some further
> developement.
> 
> But who should be blamed for bad code, the compiler developer
> at sgi or the programmer at gaussian???
> 

This answer is not only to Bernd, but is intended to clear up the
confusion regarding compiling G98 with SGI compilers.

Gaussian 98 Rev A.7  is currently certified with two SGI compilers:

1) 7.2.1 with patch3265. This is a compiler patch, so once you get the
patch you must recompile.  The patch is required to fully support the use
of 64 bit integers throughout the program. Using 64 bit integers removes
the 16Gb file size limit in previous releases of Gaussian. It also
effectively removes any memory size limitation.

2) 7.3.0 with the new sgi.make file, which is available from
[email-masked].  Rev A.7 was released before the 7.3 compilers were
widely available, so we needed to update the makefile after A.7 was
released. 

We are not aware of any general performance problem associated with the
7.3 compilers, or with the makefile we use for those compilers.  I will be
more than happy to look into any such problems. Just send them along to
[email-masked].  

The makefile for 7.3.1 has not been released yet. We are aware that
certain jobs crash/get wrong answers when this compiler is used to build
G98 Rev A.7.

The 7.2, 7.1 and earlier compilers have not been fully certified.

In general it is not safe to revert to "old" makefiles. Frequently, there
are changes which turn down optimization on subroutines which we've
discovered cause problems. The current makefile will also have the
appropriate flags for compiling code added since the earlier release.
  
Nor is it "safe" to use older compilers for the current release of
Gaussian.  By default, Gaussian uses the highest level of compiler
optimization. New code in Gaussian can trip up older compilers, sometimes
without the user being aware of it.

Using the wrong makefile or an uncertified compiler can cause crashes, and
perhaps worse than that, lead to incorrect results.

You can find the compiler and OS requirements for the latest release of
Gaussian at 

http://www.gaussian.com/g98_req.htm

Generally, technical questions about Gaussian can be addressed to
[email-masked]. We try very hard to answer all questions quickly and
accurately. 

-- 
Joseph Ochterski, Ph.D
Senior Customer Service Scientist
[email-masked]