bug_report

[John W. Eaton]

On 17-Jun-2009, Ryszard Tanas wrote:

| --------
| Bug report for Octave 3.0.5 configured for x86_64-pc-linux-gnu
| 
| Description:
| -----------
| I get the following error with my Octave running on Debian testing, when I try to find eigenvalues of the complex 15x15 matrix
| 
| ** On entry to ZGEEV  parameter number  5 had an illegal value

This message comes from LAPACK and indicates an incorrect call to
ZGEEV.

I can duplicate this error with the Octave 3.0.5 in Debian using the
1:3.0.5-6 version of the package on a system running Debian testing
(updated in the last few days).

The problem does not appear for me with a copy of Octave that I built
from the current development sources on the same system.

With 3.2.0 from Debian unstable on the same system, I see

  panic: Segmentation fault -- stopping myself...
  attempting to save variables to `octave-core'...
  save to `octave-core' complete
  Segmentation fault

The traceback is

  octave3.2:2> eig(M)
  (no debugging symbols found)

  Program received signal SIGSEGV, Segmentation fault.
  [Switching to Thread 0x7f81ae04e720 (LWP 13153)]
  0x00007f81ac5c28bf in Array<std::complex<double> >::operator= ()
     from /usr/lib/octave-3.2.0/liboctave.so
  (gdb) where
  #0  0x00007f81ac5c28bf in Array<std::complex<double> >::operator= ()
     from /usr/lib/octave-3.2.0/liboctave.so
  #1  0x00007f81a2e85cbe in EIG::operator= ()
     from /usr/lib/octave/3.2.0/oct/x86_64-pc-linux-gnu/eig.oct
  #2  0x00007f81a2e84a2a in Feig ()
     from /usr/lib/octave/3.2.0/oct/x86_64-pc-linux-gnu/eig.oct

but since Debian binaries are stripped, it's not easy to do much
debugging...

But I don't see how Octave is passing an incorrect value, and as far
as I can tell the calls to ZGEEV in liboctave/EIG.cc are the same in
Octave 3.0.5 and the current version (so would also be the same for
3.2.0).

jwe