COIN-OR::LEMON - Graph Library

source: lemon-0.x/demo/lp_demo.cc @ 1488:92755f9a4e2a

Last change on this file since 1488:92755f9a4e2a was 1435:8e85e6bbefdf, checked in by Akos Ladanyi, 15 years ago

trunk/src/* move to trunk/

File size: 3.3 KB
Line 
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  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}
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