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1 | #include <lemon/lp.h> |
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2 | #include "test_tools.h" |
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3 | |
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4 | using namespace lemon; |
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5 | |
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6 | void solveAndCheck(Mip& lp, LpSolverBase::SolutionStatus stat, |
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7 | double exp_opt) { |
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8 | using std::string; |
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9 | lp.solve(); |
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10 | //int decimal,sign; |
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11 | std::ostringstream buf; |
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12 | buf << "Primalstatus should be: " << int(stat)<<" and it is "<<int(lp.primalStatus()); |
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13 | |
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14 | // itoa(stat,buf1, 10); |
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15 | check(lp.mipStatus()==stat, buf.str()); |
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16 | |
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17 | if (stat == LpSolverBase::OPTIMAL) { |
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18 | std::ostringstream buf; |
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19 | buf << "Wrong optimal value: the right optimum is " << exp_opt; |
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20 | check(std::abs(lp.primalValue()-exp_opt) < 1e-3, buf.str()); |
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21 | //+ecvt(exp_opt,2) |
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22 | } |
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23 | } |
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24 | |
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25 | void aTest(Mip& mip) |
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26 | { |
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27 | //The following example is very simple |
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28 | |
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29 | typedef Mip::Row Row; |
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30 | typedef Mip::Col Col; |
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31 | |
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32 | |
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33 | Col x1 = mip.addCol(); |
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34 | Col x2 = mip.addCol(); |
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35 | |
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36 | |
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37 | |
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38 | |
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39 | |
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40 | |
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41 | //Objective function |
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42 | mip.setObj(x1); |
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43 | |
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44 | mip.max(); |
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45 | |
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46 | |
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47 | //Unconstrained optimization |
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48 | mip.solve(); |
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49 | //Check it out! |
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50 | |
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51 | //Constraints |
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52 | mip.addRow(2*x1+x2 <=2); |
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53 | mip.addRow(x1-2*x2 <=0); |
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54 | |
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55 | //Nonnegativity of the variable x1 |
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56 | mip.colLowerBound(x1, 0); |
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57 | |
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58 | |
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59 | |
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60 | //Maximization of x1 |
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61 | //over the triangle with vertices |
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62 | double expected_opt=4.0/5.0; |
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63 | solveAndCheck(mip, Mip::OPTIMAL, expected_opt); |
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64 | |
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65 | //Restrict x2 to integer |
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66 | mip.colType(x2,Mip::INTEGER); |
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67 | expected_opt=1.0/2.0; |
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68 | solveAndCheck(mip, Mip::OPTIMAL, expected_opt); |
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69 | |
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70 | |
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71 | //Restrict both to integer |
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72 | mip.colType(x1,Mip::INTEGER); |
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73 | expected_opt=0; |
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74 | solveAndCheck(mip, Mip::OPTIMAL, expected_opt); |
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75 | |
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76 | |
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77 | |
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78 | } |
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79 | |
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80 | |
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81 | int main() |
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82 | { |
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83 | |
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84 | #ifdef HAVE_GLPK |
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85 | MipGlpk mip1; |
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86 | aTest(mip1); |
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87 | #endif |
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88 | |
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89 | return 0; |
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90 | |
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91 | } |
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