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[2146] | 1 | #include <lemon/lp.h> |
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[2149] | 2 | #include "test_tools.h" |
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[2146] | 3 | |
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| 4 | using namespace lemon; |
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| 5 | |
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[2149] | 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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[2146] | 13 | |
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[2149] | 14 | // itoa(stat,buf1, 10); |
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[2213] | 15 | check(lp.mipStatus()==stat, buf.str()); |
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[2149] | 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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[2213] | 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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[2149] | 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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[2213] | 61 | //over the triangle with vertices |
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[2149] | 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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[2146] | 83 | |
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[2147] | 84 | #ifdef HAVE_GLPK |
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[2149] | 85 | MipGlpk mip1; |
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| 86 | aTest(mip1); |
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[2147] | 87 | #endif |
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[2146] | 88 | |
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[2147] | 89 | return 0; |
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[2146] | 90 | |
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| 91 | } |
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