demo/lp_demo.cc
author ladanyi
Tue, 14 Jun 2005 22:51:22 +0000
changeset 1490 fa2b73784343
parent 1387 37d1b20cd9ef
child 1513 b2a79aaa6867
permissions -rw-r--r--
Added support for building deb packages.
     1 #ifdef HAVE_CONFIG_H
     2 #include <config.h>
     3 #endif
     4 
     5 #include <iostream>
     6 
     7 
     8 #ifdef HAVE_GLPK
     9 #include <lemon/lp_glpk.h>
    10 #elif HAVE_CPLEX
    11 #include <lemon/lp_cplex.h>
    12 #endif
    13 
    14 using namespace lemon;
    15 
    16 #ifdef HAVE_GLPK
    17 typedef LpGlpk LpDefault;
    18 #elif HAVE_CPLEX
    19 typedef LpCplex LpDefault;
    20 #endif
    21 
    22 int main()
    23 {     
    24  //The following example is taken from the documentation of the GLPK library.
    25  //See it in the GLPK reference manual and among the GLPK sample files (sample.c)
    26   LpDefault lp;
    27   typedef LpDefault::Row Row;
    28   typedef LpDefault::Col Col;
    29 
    30   lp.max();
    31 
    32   Col x1 = lp.addCol();
    33   Col x2 = lp.addCol();
    34   Col x3 = lp.addCol();
    35 
    36   //One solution
    37   //   Row p = lp.addRow();
    38   //   Row q = lp.addRow();
    39   //   Row r = lp.addRow();
    40   //   lp.setRow(p,x1+x2+x3 <=100);  
    41   //   lp.setRow(q,10*x1+4*x2+5*x3<=600);  
    42   //   lp.setRow(r,2*x1+2*x2+6*x3<=300);  
    43 
    44   //A more elegant one
    45   //Constraints
    46   lp.addRow(x1+x2+x3 <=100);  
    47   lp.addRow(10*x1+4*x2+5*x3<=600);  
    48   lp.addRow(2*x1+2*x2+6*x3<=300);  
    49   //Nonnegativity of the variables
    50   lp.colLowerBound(x1, 0);
    51   lp.colLowerBound(x2, 0);
    52   lp.colLowerBound(x3, 0);
    53   //Objective function
    54   lp.setObj(10*x1+6*x2+4*x3);
    55   
    56   lp.solve();
    57 
    58   if (lp.primalStatus()==LpSolverBase::OPTIMAL){
    59     printf("Z = %g; x1 = %g; x2 = %g; x3 = %g\n", 
    60 	   lp.primalValue(), 
    61 	   lp.primal(x1), lp.primal(x2), lp.primal(x3));
    62   }
    63   else{
    64     std::cout<<"Optimal solution not found!"<<std::endl;
    65   }
    66 
    67 
    68   //Here comes the same problem written in C using GLPK API routines
    69 
    70 //   LPX *lp;
    71 //       int ia[1+1000], ja[1+1000];
    72 //       double ar[1+1000], Z, x1, x2, x3;
    73 // s1:   lp = lpx_create_prob();
    74 // s2:   lpx_set_prob_name(lp, "sample");
    75 // s3:   lpx_set_obj_dir(lp, LPX_MAX);
    76 // s4:   lpx_add_rows(lp, 3);
    77 // s5:   lpx_set_row_name(lp, 1, "p");
    78 // s6:   lpx_set_row_bnds(lp, 1, LPX_UP, 0.0, 100.0);
    79 // s7:   lpx_set_row_name(lp, 2, "q");
    80 // s8:   lpx_set_row_bnds(lp, 2, LPX_UP, 0.0, 600.0);
    81 // s9:   lpx_set_row_name(lp, 3, "r");
    82 // s10:  lpx_set_row_bnds(lp, 3, LPX_UP, 0.0, 300.0);
    83 // s11:  lpx_add_cols(lp, 3);
    84 // s12:  lpx_set_col_name(lp, 1, "x1");
    85 // s13:  lpx_set_col_bnds(lp, 1, LPX_LO, 0.0, 0.0);
    86 // s14:  lpx_set_obj_coef(lp, 1, 10.0);
    87 // s15:  lpx_set_col_name(lp, 2, "x2");
    88 // s16:  lpx_set_col_bnds(lp, 2, LPX_LO, 0.0, 0.0);
    89 // s17:  lpx_set_obj_coef(lp, 2, 6.0);
    90 // s18:  lpx_set_col_name(lp, 3, "x3");
    91 // s19:  lpx_set_col_bnds(lp, 3, LPX_LO, 0.0, 0.0);
    92 // s20:  lpx_set_obj_coef(lp, 3, 4.0);
    93 // s21:  ia[1] = 1, ja[1] = 1, ar[1] =  1.0; /* a[1,1] =  1 */
    94 // s22:  ia[2] = 1, ja[2] = 2, ar[2] =  1.0; /* a[1,2] =  1 */
    95 // s23:  ia[3] = 1, ja[3] = 3, ar[3] =  1.0; /* a[1,3] =  1 */
    96 // s24:  ia[4] = 2, ja[4] = 1, ar[4] = 10.0; /* a[2,1] = 10 */
    97 // s25:  ia[5] = 3, ja[5] = 1, ar[5] =  2.0; /* a[3,1] =  2 */
    98 // s26:  ia[6] = 2, ja[6] = 2, ar[6] =  4.0; /* a[2,2] =  4 */
    99 // s27:  ia[7] = 3, ja[7] = 2, ar[7] =  2.0; /* a[3,2] =  2 */
   100 // s28:  ia[8] = 2, ja[8] = 3, ar[8] =  5.0; /* a[2,3] =  5 */
   101 // s29:  ia[9] = 3, ja[9] = 3, ar[9] =  6.0; /* a[3,3] =  6 */
   102 // s30:  lpx_load_matrix(lp, 9, ia, ja, ar);
   103 // s31:  lpx_simplex(lp);
   104 // s32:  Z = lpx_get_obj_val(lp);
   105 // s33:  x1 = lpx_get_col_prim(lp, 1);
   106 // s34:  x2 = lpx_get_col_prim(lp, 2);
   107 // s35:  x3 = lpx_get_col_prim(lp, 3);
   108 // s36:  printf("\nZ = %g; x1 = %g; x2 = %g; x3 = %g\n", Z, x1, x2, x3);
   109 // s37:  lpx_delete_prob(lp);
   110 //       return 0;
   111 
   112   return 0;
   113 }