[Coin-discuss] OsiSolverInterface use and in particular OsiClpSolverInterface

[Vivian De Smedt]

Dear Osi,

To reply to FP Fasno mail asking complementary information about my problem.

In my experience of OsiSolverInterface based on Cplex and Glpk interface 
implementation lead me to define problem following the next recipe:

  - starting with an empty model
  - adding columns with no content
  - adding rows with coefficient
  - set the sense

In attachement you will find a program that work only if the INIT flag is 
defined.

It equivalent work fine for Cplex, Glpk and Vol algorhithme (that last one 
version should replace infinite bound of variable by finite one but that's 
an explicit limitation of the solver).

Hoping that it help to understand what I mean in my previous mail.

Thank to every one for your reply and contributions.

Vivian De Smedt.
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#pragma warning(disable:4786)
#include <stdio.h>
#include "OsiClpSolverInterface.hpp"
#include "CoinPackedVector.hpp"

int main()
{
	OsiClpSolverInterface *s = new OsiClpSolverInterface();
	double dEmpty = 0;
	int iEmpty = 0;
	char cEmpty = '?';

#ifdef INIT
	s->loadProblem(0, 0, &iEmpty, &iEmpty, &dEmpty, &dEmpty, &dEmpty, &dEmpty, &dEmpty, &dEmpty);
	double inf = s->getInfinity();
	CoinPackedVector c;
#endif

	s->addCol(c, 0, inf, 3);
	s->addCol(c, 0, inf, 1);

	CoinPackedVector r1;
	r1.insert(0, 2);
	r1.insert(1, 1);
	s->addRow(r1, -inf, 10);

	CoinPackedVector r2;
	r2.insert(0, 1);
	r2.insert(1, 3);
	s->addRow(r2, -inf, 15);

	s->setObjSense(-1);

	s->resolve();
	printf("%f %f\n", s->getColSolution()[0], s->getColSolution()[1]);

	s->setObjCoeff(0, 1);
	s->setObjCoeff(1, 1);

	s->resolve();
	printf("%f %f\n", s->getColSolution()[0], s->getColSolution()[1]);
	return 0;
}