Re: [Help-glpk] Assertion failed: l[k] != -DBL_MAX, Error detected in file glpios02.c at line 312

[John Kalman]

Hi Robbie

thanks for the answer. I am actually solving a MIP (mixed integer program) with glpk, I checked all the inputs and constraints and they seem to be ok (the only constrain is of the form G*x<=h and all the control variables are binary), I do not have any explicit boundaries on the control variables (since all elements x_i of vector x can be only 0 or 1). I do not understand the meaning of the constant DBL_MAX and the meaning of the assertion l[k] != -DBL_MAX, perhaps I can just delete this assertion in the source code and recompile? What could go wrong?

regards,

John

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From: Robbie Morrison <address@hidden>
To: GLPK help <address@hidden>
Cc: John Kalman <address@hidden>
Sent: Tuesday, August 28, 2012 6:22 PM
Subject: Re: [Help-glpk] Assertion failed: l[k] != -DBL_MAX, Error detected in file glpios02.c at line 312

Hello John

------------------------------------------------------------
To:          "address@hidden" <address@hidden>
Subject:      [Help-glpk] Assertion failed: l[k] != -DBL_MAX,
              Error detected in file glpios02.c at line 312
From:        John Kalman <address@hidden>
Date:        Tue, 28 Aug 2012 08:21:21 -0700 (PDT)
------------------------------------------------------------

> Hi,
>
> I am running GLPK 4.45 on linux SuSe10.x86_64, I
> recently got several times the followig run time
> error:
>
> Assertion failed: l[k] != -DBL_MAX
> Error detected in file glpios02.c at line 312

I take it that this error occurs during the translation
phase and not during the solution process.

I would look to see how you are setting the bounds on
your variables.  If this yields nothing, then it could
be a bug in the python wrapper.  Just some guesses on
my behalf, mind you.

> I am running GLPK from python (using cvx.opt.glpk
> binding). What could be the reason for this and why is
> there an assertion on line 312?

I don't understand the second part of your question.
The line count refers to 'glpios02.c' and not anything
you wrote.  Or do you mean that assertions should not
be used in production code.  If so, see here for a
C-based solution (that could perhaps be added to the
python wrapper):

  http://en.wikibooks.org/wiki/GLPK/Error_handling

Else see here:

  http://en.wikipedia.org/wiki/Assertion_(computing)

> Thanks
> John

HTH, Robbie
---
Robbie Morrison
PhD student -- policy-oriented energy system simulation
Technical University of Berlin (TU-Berlin), Germany
University email (redirected) : address@hidden
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