re: [Help-glpk] Certificates of infeasibility or unboundness

[Robbie Morrison]

Hello all

------------------------------------------------------------
To:          address@hidden
Subject:     [Help-glpk] Certificates of infeasibility or unboundness
From:        Nathann Cohen <address@hidden>
Date:        Sat, 27 Nov 2010 19:19:30 +0100
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> I am working on the software Sagemath
> (http://www.sagemath.org/) which uses GLPK, and I would
> like to get certificates of infeasibility for LP,
> something like a farkas certificate.

Can't you use something like (in C/C++, not Python):

  glp_prob* lp;
  ...
  const int status = glp_get_status(lp);

  std::string buf;
  switch ( status )
    {
      case GLP_INFEAS: buf = "soln infeasible but not proven bad"; break;
      case GLP_NOFEAS: buf = "problem proven infeasible";          break;
    }
  ...
  return buf;    // or whatever it is you need

> Thank you very much for your help ! It would be
> incredibly nice to have this feature exposed in Sage :-)

Could you tell this list something about using GLPK
from Sage (just curious)?

> Nathann Cohen
> http://www-sop.inria.fr/members/Nathann.Cohen/

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