Re: [Help-glpk] What can cause the error "Error detected in file glpios02.c"

[glpk xypron]

Hello Serveh,

> The version of GLPK that Octave is calling is 4.40.
The assert in question is in prepare_row_info() called
by basic_preprocessing() called by ios_preprocess_node()
called by ios_driver(). Hence it is called before solving
one of the subproblems in the branch and bound algorithm.

To further investigate why the assert fails in function
prepare_row_info() please replace
  assert(a!=a);
in line 134 of glpk-4.40/src/glpios02.c or
line 135 of glpk-4.44/src/glpios02.c by
  xerror("Error in prepare_row_info, a = %g", a);
and compile and install the GLPK library.

Please, inform me if a == 0 or if a == NaN.

The source package can be downloaded from
ftp://ftp.gnu.org/gnu/glpk/

Unzip and untar the source archive.

On Linux use 
./configure;make;sudo make install;sudo ldconfig

On Windows change to the w32 or w64 directory depending on whether
you are using a 32 or 64bit version of Octave and use the
supplied build files together with Visual C++ Express and the
the Windows SDK for compiling.


> by the way, how can I find out when this assert is reached in octave?
The current version of GLPK (4.44) has an error hook function which
allows a calling application to gracefully handle errors in the
GLPK library. Please, ask the Octave developpers to use it.

glp_error_hook() is documented in src/glpk.pdf of the source
distribution of GLPK.

A coding example can be found at
http://winglpk.svn.sourceforge.net/viewvc/winglpk/trunk/examples/c/glp_error_hook_demo.c?revision=24&content-type=text%2Fplain

Best regards

Xypron

-------- Original-Nachricht --------
> Datum: Thu, 22 Jul 2010 10:21:38 +0200
file glpios02.c"

> The version of GLPK that Octave is calling is 4.40.
> by the way, how can I find out when this assert is reached in octave?
> 
> Thanks,
> Serveh
> On 7/22/2010 7:44 AM, glpk xypron wrote:
> > Hello Serveh,
> >
> >    
> >>> Assertion failed: a != a
> >>> Error detected in file glpios02.c at line 134
> >>> panic: Aborted -- stopping myself...
> >>>        
> > line 134 simply always creates an error because the programmer
> > thought that this line should never be reached.
> >
> > Please, have a look into the source code to find out
> > when this assert is reached.
> >
> > GLPK 4.44 is the current version of GLPK.
> > There is no assert in line 134 of glpk-4.44/src/glpios02.c.
> > Please specify the version of GLPK you are using.
> >
> > Best regards
> >
> > Xypron
> > -------- Original-Nachricht --------
> >    
> >> Datum: Wed, 21 Jul 2010 22:14:33 +0200
> >> Betreff: [Help-glpk] What can cause the error "Error detected in
> file  glpios02.c"
> >>      
> >    
> >> Hi all,
> >>
> >> I am using GLPK under octave interface for a mixed integer programming
> >> problem, however when running the solver I am facing the following
> error:
> >>
> >> Assertion failed: a != a
> >> Error detected in file glpios02.c at line 134
> >> panic: Aborted -- stopping myself...
> >>
> >> Then also the octave is aborted. I am wondering if anyone what may
> cause
> >> this error.
> >>
> >> Thanks,
> >> Serveh

-- 
Neu: GMX De-Mail - Einfach wie E-Mail, sicher wie ein Brief!  
Jetzt De-Mail-Adresse reservieren: http://portal.gmx.net/de/go/demail