Bug#344281: [Pkg-octave-devel] Bug#344281: panic: Illegal instruction in det(eye(x))

[Douglas Bates]

On 12/21/05, Dirk Eddelbuettel <edd at debian.org> wrote:
>
> On 21 December 2005 at 20:18, joshua at nirmalvihar.info wrote:
> | Package: octave2.9
> | Version: 2.9.4-8
> | Severity: normal
> |
> | I tried to octave2.1 also, det(eye(9)) gives a panic: Illegal
> | instruction.  det(eye(4)), 5, 6, 7, 8 works though.  It's a mystery.
>
> I very vaguely recall a bug report with respect to Lapack that came up in R
> that was triggered by one matrix size only. If memory serves, it was 9 as
> well. This is the reason we build R with its own copy of Lapack.
>
> I cannot recall what the exact circumstances were, but maybe Doug or Brian
> (CC'ed) can remember ?

I believe that bug was in an eigenvalue-eigenvector calculation.  I
imagine this calculation is done using an LU decomposition or, if the
matrix is recognized as being symmetric, a Bunch-Kaufman
decomposition.

Can you create a traceback to show where it is generating the illegal
instruction?
> Regards, Dirk
> |
> | -- System Information:
> | Debian Release: 3.0
> |   APT prefers testing
> |   APT policy: (500, 'testing')
> | Architecture: i386 (i686)
> | Kernel: Linux 2.6.14-b1
> | Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8
> |
> | Versions of packages octave2.9 depends on:
> | ii  atlas3-base [liblapack.so.3]  3.6.0-19   Automatically Tuned Linear Algebra
> | ii  fftw3                         3.0.1-11   Library for computing Fast Fourier
> | ii  libc6                         2.3.5-3    GNU C Library: Shared libraries an
> | ii  libgcc1                       1:4.0.2-5  GCC support library
> | ii  libgfortran0                  4.0.2-5    Runtime library for GNU Fortran ap
> | ii  libglpk0                      4.8-3      linear programming kit (shared lib
> | ii  libhdf5-serial-1.6.4-0c2 [lib 1.6.4-4    Hierarchical Data Format 5 (HDF5)
> | ii  libncurses5                   5.4-9      Shared libraries for terminal hand
> | ii  libreadline5                  5.0-10     GNU readline and history libraries
> | ii  libstdc++6                    4.0.2-5    The GNU Standard C++ Library v3
> | ii  libumfpack4                   4.4-3      set of routines for solving unsymm
> | ii  texinfo                       4.6-1      Documentation system for on-line i
> | ii  zlib1g                        1:1.2.2-8  compression library - runtime
> |
> | -- no debconf information
> |
> |
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>
> --
> Hell, there are no rules here - we're trying to accomplish something.
>                                                   -- Thomas A. Edison
>