COIN-OR::LEMON - Graph Library

source: lemon-0.x/src/demo/lp_demo.cc @ 1381:998e8def9676

Last change on this file since 1381:998e8def9676 was 1381:998e8def9676, checked in by Alpar Juttner, 15 years ago
  • lp_cplex.h, lp_cplex.cc added
  • lp_demo.cc and lp_maxflow_demo.cc uses GLPK is it is found CPLEX otherwise
File size: 3.2 KB
Line 
1#include <iostream>
2
3
4#ifdef HAVE_GLPK
5#include <lemon/lp_glpk.h>
6#elif HAVE_CPLEX
7#include <lemon/lp_cplex.h>
8#endif
9
10using namespace lemon;
11
12#ifdef HAVE_GLPK
13typedef LpGlpk LpDefault;
14#elif HAVE_CPLEX
15typedef LpCplex LpDefault;
16#endif
17
18int main()
19{     
20 //The following example is taken from the documentation of the GLPK library.
21 //See it in the GLPK reference manual and among the GLPK sample files (sample.c)
22  LpDefault lp;
23  typedef LpDefault::Row Row;
24  typedef LpDefault::Col Col;
25
26  lp.max();
27
28  Col x1 = lp.addCol();
29  Col x2 = lp.addCol();
30  Col x3 = lp.addCol();
31
32  //One solution
33  //   Row p = lp.addRow();
34  //   Row q = lp.addRow();
35  //   Row r = lp.addRow();
36  //   lp.setRow(p,x1+x2+x3 <=100); 
37  //   lp.setRow(q,10*x1+4*x2+5*x3<=600); 
38  //   lp.setRow(r,2*x1+2*x2+6*x3<=300); 
39
40  //A more elegant one
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  lp.solve();
53
54  if (lp.primalStatus()==LpSolverBase::OPTIMAL){
55    printf("Z = %g; x1 = %g; x2 = %g; x3 = %g\n",
56           lp.primalValue(),
57           lp.primal(x1), lp.primal(x2), lp.primal(x3));
58  }
59  else{
60    std::cout<<"Optimal solution not found!"<<std::endl;
61  }
62
63
64  //Here comes the same problem written in C using GLPK API routines
65
66//   LPX *lp;
67//       int ia[1+1000], ja[1+1000];
68//       double ar[1+1000], Z, x1, x2, x3;
69// s1:   lp = lpx_create_prob();
70// s2:   lpx_set_prob_name(lp, "sample");
71// s3:   lpx_set_obj_dir(lp, LPX_MAX);
72// s4:   lpx_add_rows(lp, 3);
73// s5:   lpx_set_row_name(lp, 1, "p");
74// s6:   lpx_set_row_bnds(lp, 1, LPX_UP, 0.0, 100.0);
75// s7:   lpx_set_row_name(lp, 2, "q");
76// s8:   lpx_set_row_bnds(lp, 2, LPX_UP, 0.0, 600.0);
77// s9:   lpx_set_row_name(lp, 3, "r");
78// s10:  lpx_set_row_bnds(lp, 3, LPX_UP, 0.0, 300.0);
79// s11:  lpx_add_cols(lp, 3);
80// s12:  lpx_set_col_name(lp, 1, "x1");
81// s13:  lpx_set_col_bnds(lp, 1, LPX_LO, 0.0, 0.0);
82// s14:  lpx_set_obj_coef(lp, 1, 10.0);
83// s15:  lpx_set_col_name(lp, 2, "x2");
84// s16:  lpx_set_col_bnds(lp, 2, LPX_LO, 0.0, 0.0);
85// s17:  lpx_set_obj_coef(lp, 2, 6.0);
86// s18:  lpx_set_col_name(lp, 3, "x3");
87// s19:  lpx_set_col_bnds(lp, 3, LPX_LO, 0.0, 0.0);
88// s20:  lpx_set_obj_coef(lp, 3, 4.0);
89// s21:  ia[1] = 1, ja[1] = 1, ar[1] =  1.0; /* a[1,1] =  1 */
90// s22:  ia[2] = 1, ja[2] = 2, ar[2] =  1.0; /* a[1,2] =  1 */
91// s23:  ia[3] = 1, ja[3] = 3, ar[3] =  1.0; /* a[1,3] =  1 */
92// s24:  ia[4] = 2, ja[4] = 1, ar[4] = 10.0; /* a[2,1] = 10 */
93// s25:  ia[5] = 3, ja[5] = 1, ar[5] =  2.0; /* a[3,1] =  2 */
94// s26:  ia[6] = 2, ja[6] = 2, ar[6] =  4.0; /* a[2,2] =  4 */
95// s27:  ia[7] = 3, ja[7] = 2, ar[7] =  2.0; /* a[3,2] =  2 */
96// s28:  ia[8] = 2, ja[8] = 3, ar[8] =  5.0; /* a[2,3] =  5 */
97// s29:  ia[9] = 3, ja[9] = 3, ar[9] =  6.0; /* a[3,3] =  6 */
98// s30:  lpx_load_matrix(lp, 9, ia, ja, ar);
99// s31:  lpx_simplex(lp);
100// s32:  Z = lpx_get_obj_val(lp);
101// s33:  x1 = lpx_get_col_prim(lp, 1);
102// s34:  x2 = lpx_get_col_prim(lp, 2);
103// s35:  x3 = lpx_get_col_prim(lp, 3);
104// s36:  printf("\nZ = %g; x1 = %g; x2 = %g; x3 = %g\n", Z, x1, x2, x3);
105// s37:  lpx_delete_prob(lp);
106//       return 0;
107
108  return 0;
109}
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