[Coin-discuss] Osi interfaces do not return MIP status appropriately!

[Vishy Jeet]

Hi everyone,

I am using an MPS file which is located at the following location:
http://uts.cc.utexas.edu/~jeetv/MIPproblem.mps (too big to be posted
here...)

When I am using the following code it returns the message isAbandoned
regardless
whether branchAndBound() is called or not....but if I use Cbc solver
directly, it returns the primal infeasibility. Could you check if the status
functions (called in the code below) written OsiCbcSolverInterface() are
working properly..

regards,
vishy

*Code for solving the MPS file using Osi interface:*

#include <iostream.h>
#include "OsiCbcSolverInterface.hpp"

int main() {
  MP_model my_knap(new OsiCbcSolverInterface);
  int num_err = 0;
  num_err = my_knap->readMps("MIPproblem");
  if(num_err != 0)
  cout << "errors reading MPS file\n";

  my_knap->branchAndBound();

  if( my_knap->isProvenPrimalInfeasible() == true)
    cout << "primal infeasible\n";
   if( my_knap->isProvenDualInfeasible() == true)
    cout << "dual infeasible\n";
  if( my_knap->isAbandoned() == true)
    cout << "isAbandoned\n";
  if( my_knap->isProvenOptimal() == true)
    cout << "isProvenOptimal\n";
   if( my_knap->isDualObjectiveLimitReached() == true)
    cout << "isDualObjectiveLimitReached\n";
  if( my_knap->isPrimalObjectiveLimitReached() == true)
    cout << "isPrimalObjectiveLimitReached\n";
  if( my_knap->isIterationLimitReached() == true)
    cout << "isIterationLimitReached\n";
}
executabe  prints "*isAbandoned*"....



 *Code for solving the MPS file using Cbc directly:*

*Using minimum.cpp in Cbc examples --aalong with the following test:*

 33   if (model.isProvenInfeasible () == true)
 34     cout<< "YES"<<endl;
 35   else
 36     cout<< "NO"<<endl;

executabe  prints "*YES*"....

















-- 
Best Regards,
Vishv Jeet, Ph.D.,
Operations Research Scientist,
Gravitant Inc.,
(The Business Governance Company)
http://www.gravitant.com
Austin, TX, USA.
Cell    : 1-512-657-8678
Home : 1-512-788-5795
Work  : 1-512-535-7399
_______________________
Youngest Music Meastro
http://www.mayanksahu.net
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