test/mip_test.cc
author alpar
Tue, 20 Feb 2007 15:53:33 +0000
changeset 2375 e30a0fdad0d7
parent 2267 3575f17a6e7f
child 2386 81b47fc5c444
permissions -rw-r--r--
A preflow based general network circulation algorithm and a simple demo
     1 #include "test_tools.h"
     2 
     3 
     4 #ifdef HAVE_CONFIG_H
     5 #include <config.h>
     6 #endif
     7 
     8 #ifdef HAVE_CPLEX
     9 #include <lemon/mip_cplex.h>
    10 #endif
    11 
    12 #ifdef HAVE_GLPK
    13 #include <lemon/mip_glpk.h>
    14 #endif
    15 
    16 
    17 using namespace lemon;
    18 
    19 void solveAndCheck(MipSolverBase& lp, MipSolverBase::SolutionStatus stat, 
    20 		   double exp_opt) {
    21   using std::string;
    22 
    23   lp.solve();
    24   //int decimal,sign;
    25   std::ostringstream buf;
    26   buf << "Primalstatus should be: " << int(stat)<<" and it is "<<int(lp.primalStatus());
    27 
    28 
    29   //  itoa(stat,buf1, 10);
    30   check(lp.mipStatus()==stat, buf.str());
    31 
    32   if (stat ==  MipSolverBase::OPTIMAL) {
    33     std::ostringstream buf;
    34     buf << "Wrong optimal value: the right optimum is " << exp_opt; 
    35     check(std::abs(lp.primalValue()-exp_opt) < 1e-3, buf.str());
    36     //+ecvt(exp_opt,2)
    37   }
    38 }
    39 
    40 void aTest(MipSolverBase& mip)
    41 {
    42  //The following example is very simple
    43 
    44 
    45   typedef MipSolverBase::Row Row;
    46   typedef MipSolverBase::Col Col;
    47 
    48 
    49 
    50   Col x1 = mip.addCol();
    51   Col x2 = mip.addCol();
    52 
    53 
    54   //Objective function
    55   mip.obj(x1);
    56 
    57   mip.max();
    58 
    59 
    60   //Unconstrained optimization
    61   mip.solve();
    62   //Check it out!
    63 
    64   //Constraints
    65   mip.addRow(2*x1+x2 <=2);  
    66   mip.addRow(x1-2*x2 <=0);  
    67 
    68   //Nonnegativity of the variable x1
    69   mip.colLowerBound(x1, 0);
    70 
    71 
    72 
    73   //Maximization of x1
    74   //over the triangle with vertices (0,0),(4/5,2/5),(0,2)
    75   double expected_opt=4.0/5.0;
    76   solveAndCheck(mip, MipSolverBase::OPTIMAL, expected_opt);
    77 
    78   //Restrict x2 to integer
    79   mip.colType(x2,MipSolverBase::INT);  
    80   expected_opt=1.0/2.0;
    81   solveAndCheck(mip, MipSolverBase::OPTIMAL, expected_opt);
    82 
    83 
    84   //Restrict both to integer
    85   mip.colType(x1,MipSolverBase::INT);  
    86   expected_opt=0;
    87   solveAndCheck(mip, MipSolverBase::OPTIMAL, expected_opt);
    88 
    89  
    90 
    91 }
    92 
    93 
    94 int main() 
    95 {
    96 
    97 #ifdef HAVE_GLPK
    98   MipGlpk mip1;
    99   aTest(mip1);
   100 #endif
   101 
   102 #ifdef HAVE_CPLEX
   103   MipCplex mip2;
   104   aTest(mip2);
   105 #endif
   106 
   107   return 0;
   108 
   109 }