test/mip_test.cc
author deba
Thu, 14 Sep 2006 19:58:29 +0000
changeset 2217 4a10a45d55f6
parent 2149 b437bdee6fd0
child 2218 50f1a780a5ff
permissions -rw-r--r--
Doc fix
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#include <lemon/lp.h>
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#include "test_tools.h"
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using namespace lemon;
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void solveAndCheck(Mip& lp, LpSolverBase::SolutionStatus stat, 
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		   double exp_opt) {
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  using std::string;
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  lp.solve();
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  //int decimal,sign;
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  std::ostringstream buf;
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  buf << "Primalstatus should be: " << int(stat)<<" and it is "<<int(lp.primalStatus());
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  //  itoa(stat,buf1, 10);
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  check(lp.mipStatus()==stat, buf.str());
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  if (stat ==  LpSolverBase::OPTIMAL) {
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    std::ostringstream buf;
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    buf << "Wrong optimal value: the right optimum is " << exp_opt; 
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    check(std::abs(lp.primalValue()-exp_opt) < 1e-3, buf.str());
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    //+ecvt(exp_opt,2)
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  }
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}
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void aTest(Mip& mip)
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{
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 //The following example is very simple
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  typedef Mip::Row Row;
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  typedef Mip::Col Col;
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  Col x1 = mip.addCol();
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  Col x2 = mip.addCol();
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  //Objective function
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  mip.setObj(x1);
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  mip.max();
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  //Unconstrained optimization
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  mip.solve();
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  //Check it out!
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  //Constraints
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  mip.addRow(2*x1+x2 <=2);  
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  mip.addRow(x1-2*x2 <=0);  
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  //Nonnegativity of the variable x1
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  mip.colLowerBound(x1, 0);
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  //Maximization of x1
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  //over the triangle with vertices 
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  double expected_opt=4.0/5.0;
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  solveAndCheck(mip, Mip::OPTIMAL, expected_opt);
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  //Restrict x2 to integer
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  mip.colType(x2,Mip::INTEGER);  
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  expected_opt=1.0/2.0;
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  solveAndCheck(mip, Mip::OPTIMAL, expected_opt);
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  //Restrict both to integer
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  mip.colType(x1,Mip::INTEGER);  
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  expected_opt=0;
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  solveAndCheck(mip, Mip::OPTIMAL, expected_opt);
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}
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int main() 
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{
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#ifdef HAVE_GLPK
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  MipGlpk mip1;
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  aTest(mip1);
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#endif
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  return 0;
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}