Hello Andrew,
http://www.sce.carleton.ca/faculty/chinneck/docs/InfeasibilityTutorial.pdf
gives an overview of heuristics used by other codes to determine an
"irreducible infeasible subset" (IIS).
The following paper might be of interest too:
J.W. Chinneck, (1996), "An Effective Polynomial-Time H
> I have tested the suggestion concerning glpsol -o for a trivial
> example with glpk-4.28:
> var x;
> var y;
> minimize obj : x + y;
> s.t. c0 : x + 3 * y >= 0;
> s.t. c4 : y <= 10;
> s.t. c1 : x + 4 <= 0;
s.t. c2 : x + 3 >>= 0;
> A line "KKT.PB" was not issued.
This is because you did not disa
> It was actually more economical for me to go to the source code on
> this. In the time it would take glpsol to provide the KKT info
> (several hours), I threw some lines into glpk and got the info I
> needed. Of course, I have no idea if what I added will break other
> things or will work for a
I just realized I diff'ed against my most recent version which is 4.23. Hope
that doesn't cause problems.
Joey
_
The i’m Talkathon starts 6/24/08. For now, give amongst yourselves.
http://www.imtalkathon.com?source=TXT_EML_WLH_Lea
ple = col->j;
+ return 2;
+ }
}
else
{ /* general column analysis */
> Could you, please, mail your coding suggestion to the mail list.
>
> Best regards
>
> Xypron
>
> Original-Nachricht ---
; Datum: Wed, 18 Jun 2008 11:29:38 -0700
> Von: Joey Rios
> An: "help-glpk@gnu.org"
> Betreff: RE: [Help-glpk] Getting more info from presolver
> > You may look at the output listing produced by either glpsol (with
> > -o option) or the api routine lpx_print_sol.
&
> You may look at the output listing produced by either glpsol (with
> -o option) or the api routine lpx_print_sol.
It was actually more economical for me to go to the source code on this. In
the time it would take glpsol to provide the KKT info (several hours), I threw
some lines into glpk an
> > So this brings me to
> > the hope that the glpk presolver could offer more insight about which
> > constraints it finds unsatisfiable. Even if it told me one of them,
> > it would be a great clue for my debugging. If there is a way to do
> > this through the API (vs. glpsol), that's fine too
> I saw a couple of threads on this topic, but I don't think they
> completely answered my question. I am getting the "PROBLEM HAS NO
> PRIMAL FEASIBLE SOLUTION" from glpsol. This doesn't surprise me as I
> am currently debugging my input file. I have a MathProg model of my
> problem by my dat
Hi,
I saw a couple of threads on this topic, but I don't think they completely
answered my question. I am getting the "PROBLEM HAS NO PRIMAL FEASIBLE
SOLUTION" from glpsol. This doesn't surprise me as I am currently debugging my
input file. I have a MathProg model of my problem by my data
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