[Octave-bug-tracker] [bug #45484] mldivide/mrdivide crashes octave 4 on windows, triggers exception on Linux and MacOSX

[Rik]

Update of bug #45484 (project octave):

                  Status:                    None => Confirmed              

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Follow-up Comment #1:

Confirmed on Windows XP Virtual Machine, Octave 4.0.0 from installer.  I tried
both with octave-gui.exe and octave-cli.exe and both have the problem.  When
running from the CLI there is at least some reporting of the problem, the same
error message you saw.


warning: matrix singular to machine precision, rcond = nan

        On entry to DLASCL parameter number 4 had an illegal value


I also get a pop-up error message from Windows that an instruction tried to
read from memory location 0x10 which is bound to be a segmentation violation.

However, on Linux (Ubuntu 12.04), I don't get an exception.  I do get a
warning about the matrix being singular.  In addition, the output is all zeros
instead of being all NaNs.


y = NaN (4)
y =

   NaN   NaN   NaN   NaN
   NaN   NaN   NaN   NaN
   NaN   NaN   NaN   NaN
   NaN   NaN   NaN   NaN

>> y / y
warning: matrix singular to machine precision
ans =

   0   0   0   0
   0   0   0   0
   0   0   0   0
   0   0   0   0

>> mrdivide (y,y)
ans =

   0   0   0   0
   0   0   0   0
   0   0   0   0
   0   0   0   0

>> mldivide (y,y)
ans =

   0   0   0   0
   0   0   0   0
   0   0   0   0
   0   0   0   0


Interestingly, if I change the matrix slightly, I can generate the same
warning on Linux as well.


y = Nan (4);
y(3,3) = 1;
y / y
warning: matrix singular to machine precision
 ** On entry to DLASCL parameter number  4 had an illegal value
error: exception encountered in Fortran subroutine dgelsd_




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