From maintainers-request at octave dot org Fri Nov 12 10:14:05 2004
Subject: Re: gcc 3.4 and Octave/lapack problems
From: "Dmitri A. Sergatskov" <dmitri at unm dot edu>
To: Quentin Spencer <qspencer at ieee dot org>
CC: Jskud at Jskud dot com, "John W. Eaton" <jwe@bevo.che.wisc.edu>,         maintainers@octave.org
Date: Fri, 12 Nov 2004 09:10:59 -0700

Quentin Spencer wrote:
> I also installed Fedora Core 3 and saw the same problems. I looked this 
> morning on the Red Hat ftp server and noticed the development branch had 
> an updated version of lapack:
> http://download.fedora.redhat.com/pub/fedora/linux/core/development/SRPMS/lapack-3.0-26.src.rpm 
> 
> I downloaded the SRPM and rebuilt it, and the linear algebra functions 
> like eig appear to be working correctly now (I'm using the same octave 
> 2.1.61 I compiled yesterday with no changes). I have attached the SPEC 
> file. It appears to only change the -O flags. This updated release was 
> in response to a separate bug that was reported in lapack:
> https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=138447
> 

Thanks for pointing this bug out to me. I add my $0.10 to it :)
I believe a) this is a gcc issue, b) the "fix" by recompiling
with -O is fortuitous, and real fix is to do -ffloat-store.

> I haven't done very thorough testing (I haven't tested Dmitri's Fortran 
> code, for example), but I don't see any problems so far.

Besides problems with eig() I found that schur() would run much slower
with broken lapack.

> 
> Quentin
> 

Dmitri.
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