From bug-octave-request at bevo dot che dot wisc dot edu Tue Mar  2 08:16:09 2004
Subject: BUG: lu seg faults on Tru64
From: "John W. Eaton" <jwe at bevo dot che dot wisc dot edu>
To: hans dot ekkehard dot plesser at nlh dot no
Cc: bug-octave at bevo dot che dot wisc dot edu
Date: Tue, 2 Mar 2004 08:15:12 -0600

On  2-Mar-2004, Dr. Hans Ekkehard Plesser <hans dot ekkehard dot plesser at nlh dot no> wrote:

| The LU decomposition routine lu() causes segmentation faults on a
| AlphaServer GS1280 under Tru64 Unix V5.1B.  The error seems to occur
| reliably when attempting an LU decomposition of 3x2 matrices:

| The error occurs with 2.1.55 and 2.1.53.  I tried recompiling in a
| more defensive way (-O2, no processor specific optimizations), but
| to no avail.  I compiled with Compaq cc, cxx, f77 and linked against
| Compaq CXML for Blas and Lapack.

I'd guess CXML is the problem.  What version of Lapack is it based on?

Can you try rebuilding without the vendor lapack/blas?

| Is there any technical documentation on the octave code, to help me
| in tracing errors?

No, but lots of people find the sources relatively easy to follow.
Check the file src/dbleLU.cc.  That's where the call to the Lapack
factorization routine dgetrf happens.

jwe



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