COIN-OR::LEMON - Graph Library

source: lemon-0.x/demo/lp_demo.cc @ 1530:d99c3c84f797

Last change on this file since 1530:d99c3c84f797 was 1530:d99c3c84f797, checked in by athos, 14 years ago

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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
14using namespace lemon;
15
16#ifdef HAVE_GLPK
17typedef LpGlpk LpDefault;
18#elif HAVE_CPLEX
19typedef LpCplex LpDefault;
20#endif
21
22int 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
27  //A default solver is taken
28  LpDefault lp;
29  typedef LpDefault::Row Row;
30  typedef LpDefault::Col Col;
31 
32
33  //This will be a maximization
34  lp.max();
35
36  //We add coloumns (variables) to our problem
37  Col x1 = lp.addCol();
38  Col x2 = lp.addCol();
39  Col x3 = lp.addCol();
40
41  //Constraints
42  lp.addRow(x1+x2+x3 <=100); 
43  lp.addRow(10*x1+4*x2+5*x3<=600); 
44  lp.addRow(2*x1+2*x2+6*x3<=300); 
45  //Nonnegativity of the variables
46  lp.colLowerBound(x1, 0);
47  lp.colLowerBound(x2, 0);
48  lp.colLowerBound(x3, 0);
49  //Objective function
50  lp.setObj(10*x1+6*x2+4*x3);
51 
52  //Call the routine of the underlying LP solver
53  lp.solve();
54
55  //Print results
56  if (lp.primalStatus()==LpSolverBase::OPTIMAL){
57    printf("Z = %g; x1 = %g; x2 = %g; x3 = %g\n",
58           lp.primalValue(),
59           lp.primal(x1), lp.primal(x2), lp.primal(x3));
60  }
61  else{
62    std::cout<<"Optimal solution not found!"<<std::endl;
63  }
64
65  //End of LEMON style code
66
67  //Here comes the same problem written in C using GLPK API routines
68
69//   LPX *lp;
70//       int ia[1+1000], ja[1+1000];
71//       double ar[1+1000], Z, x1, x2, x3;
72// s1:   lp = lpx_create_prob();
73// s2:   lpx_set_prob_name(lp, "sample");
74// s3:   lpx_set_obj_dir(lp, LPX_MAX);
75// s4:   lpx_add_rows(lp, 3);
76// s5:   lpx_set_row_name(lp, 1, "p");
77// s6:   lpx_set_row_bnds(lp, 1, LPX_UP, 0.0, 100.0);
78// s7:   lpx_set_row_name(lp, 2, "q");
79// s8:   lpx_set_row_bnds(lp, 2, LPX_UP, 0.0, 600.0);
80// s9:   lpx_set_row_name(lp, 3, "r");
81// s10:  lpx_set_row_bnds(lp, 3, LPX_UP, 0.0, 300.0);
82// s11:  lpx_add_cols(lp, 3);
83// s12:  lpx_set_col_name(lp, 1, "x1");
84// s13:  lpx_set_col_bnds(lp, 1, LPX_LO, 0.0, 0.0);
85// s14:  lpx_set_obj_coef(lp, 1, 10.0);
86// s15:  lpx_set_col_name(lp, 2, "x2");
87// s16:  lpx_set_col_bnds(lp, 2, LPX_LO, 0.0, 0.0);
88// s17:  lpx_set_obj_coef(lp, 2, 6.0);
89// s18:  lpx_set_col_name(lp, 3, "x3");
90// s19:  lpx_set_col_bnds(lp, 3, LPX_LO, 0.0, 0.0);
91// s20:  lpx_set_obj_coef(lp, 3, 4.0);
92// s21:  ia[1] = 1, ja[1] = 1, ar[1] =  1.0; /* a[1,1] =  1 */
93// s22:  ia[2] = 1, ja[2] = 2, ar[2] =  1.0; /* a[1,2] =  1 */
94// s23:  ia[3] = 1, ja[3] = 3, ar[3] =  1.0; /* a[1,3] =  1 */
95// s24:  ia[4] = 2, ja[4] = 1, ar[4] = 10.0; /* a[2,1] = 10 */
96// s25:  ia[5] = 3, ja[5] = 1, ar[5] =  2.0; /* a[3,1] =  2 */
97// s26:  ia[6] = 2, ja[6] = 2, ar[6] =  4.0; /* a[2,2] =  4 */
98// s27:  ia[7] = 3, ja[7] = 2, ar[7] =  2.0; /* a[3,2] =  2 */
99// s28:  ia[8] = 2, ja[8] = 3, ar[8] =  5.0; /* a[2,3] =  5 */
100// s29:  ia[9] = 3, ja[9] = 3, ar[9] =  6.0; /* a[3,3] =  6 */
101// s30:  lpx_load_matrix(lp, 9, ia, ja, ar);
102// s31:  lpx_simplex(lp);
103// s32:  Z = lpx_get_obj_val(lp);
104// s33:  x1 = lpx_get_col_prim(lp, 1);
105// s34:  x2 = lpx_get_col_prim(lp, 2);
106// s35:  x3 = lpx_get_col_prim(lp, 3);
107// s36:  printf("\nZ = %g; x1 = %g; x2 = %g; x3 = %g\n", Z, x1, x2, x3);
108// s37:  lpx_delete_prob(lp);
109//       return 0;
110
111  return 0;
112}
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