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