RE: [Bug-glpk] Crash in 4.38

[Wenchel, Seth]

Okay I did some more testing.  

The error seems to happen randomly, or at least it is not always at the exact 
same point in the optimization.  It does, however, always happen.

When I've been getting this error it has been while running glpk 4.38 on WinXP 
which is running inside of a virtual machine (Parallels Desktop 4.0) on top of 
Mac OS X 10.5.  That being said, I figured out how to install 4.37 natively on 
Mac OS X (macs are new to me).  I've tried running the problem several times 
and so far it has worked each time. 

-seth


-----Original Message-----
From: Andrew Makhorin [mailto:address@hidden
Sent: Fri 7/3/2009 9:41 AM
To: Wenchel, Seth
Cc: address@hidden
Subject: Re: [Bug-glpk] Crash in 4.38
 
> I'm running 4.38 on winXP (inside a VM on top of Mac OS 10.5). When I
> try to optimize the attached file I get the following error:

> Assertion failed: xlcmp(env->t_last, t) <= 0
> Error detected in file ..\src\glplib10.c at line 109

> The attached file is the smallest example I constructed that fails.
> The few that I tried smaller than this worked.  Of course, this
> problem is tiny compared to what I'd really like to run.

Thank you for your bug report.

The error appears in the internal timer routine (xtime), and it is
not related to the instance you are solving. It appears, because
the timer value determined by the routine happens to be less than
its value in the past.

Does the error happen regularly or randomly? On which platform are
you running glpk?


Andrew Makhorin