[Octave-bug-tracker] [bug #30035] The back division operator crashes Octave

[anonymous]

URL:
  <http://savannah.gnu.org/bugs/?30035>

                 Summary: The back division operator crashes Octave
                 Project: GNU Octave
            Submitted by: None
            Submitted on: Wed 02 Jun 2010 11:13:33 AM UTC
                Category: None
                Severity: 3 - Normal
              Item Group: Crash
                  Status: None
             Assigned to: None
         Originator Name: ESP
        Originator Email: address@hidden
             Open/Closed: Open
         Discussion Lock: Any
                 Release: 3.2.3
        Operating System: GNU/Linux

    _______________________________________________________

Details:

A fatal error arises when using the back division operator to solve a linear
system of equations with more equations than unknowns.
Such a system can be used to deconvolve a signal for example, where the
(full) convolved data is typically larger than the original data, and using a
circulant matrix made from the convolution filter as the equations
coefficients.
The same code works correctly in Matlab (for the purpose of deconvolution,
not tried for other systems of equations).

The simpler example below is used to illustrate a typical situation for the
bug to occur. It does not use a circulant matrix but the same bug appears in
Octave (and not in Matlab).
It seems that this bug is due to the use of inv and/or pinv (same bug appears
when using inv and pinv on that matrix - even if the matrix is not invertible,
at least it should not crash)


octave:1> mat1 = rand(200, 362);
octave:2> vect1 = rand(200, 1);
octave:3> mat1\vect1;
panic: Illegal instruction -- stopping myself...
attempting to save variables to `octave-core'...
save to `octave-core' complete
Illegal instruction (core dumped)





    _______________________________________________________

Reply to this item at:

  <http://savannah.gnu.org/bugs/?30035>

_______________________________________________
  Message sent via/by Savannah
  http://savannah.gnu.org/