1 | /* $Id: AbcDualRowDantzig.hpp 2385 2019-01-06 19:43:06Z stefan $ */ |
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2 | // Copyright (C) 2002, International Business Machines |
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3 | // Corporation and others, Copyright (C) 2012, FasterCoin. All Rights Reserved. |
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4 | // This code is licensed under the terms of the Eclipse Public License (EPL). |
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5 | |
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6 | #ifndef AbcDualRowDantzig_H |
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7 | #define AbcDualRowDantzig_H |
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8 | |
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9 | #include "AbcDualRowPivot.hpp" |
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10 | |
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11 | //############################################################################# |
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12 | |
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13 | /** Dual Row Pivot Dantzig Algorithm Class |
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14 | |
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15 | This is simplest choice - choose largest infeasibility |
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16 | |
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17 | */ |
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18 | |
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19 | class AbcDualRowDantzig : public AbcDualRowPivot { |
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20 | |
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21 | public: |
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22 | ///@name Algorithmic methods |
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23 | //@{ |
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24 | |
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25 | /// Returns pivot row, -1 if none |
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26 | virtual int pivotRow(); |
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27 | |
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28 | /** Updates weights and returns pivot alpha. |
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29 | Also does FT update */ |
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30 | virtual double updateWeights(CoinIndexedVector &input, CoinIndexedVector &updatedColumn); |
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31 | virtual double updateWeights1(CoinIndexedVector &input, CoinIndexedVector &updateColumn); |
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32 | virtual void updateWeightsOnly(CoinIndexedVector & /*input*/) {}; |
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33 | /// Actually updates weights |
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34 | virtual void updateWeights2(CoinIndexedVector &input, CoinIndexedVector & /*updateColumn*/) { input.clear(); }; |
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35 | /** Updates primal solution (and maybe list of candidates) |
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36 | Uses input vector which it deletes |
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37 | Computes change in objective function |
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38 | */ |
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39 | virtual void updatePrimalSolution(CoinIndexedVector &input, |
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40 | double theta); |
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41 | /** Saves any weights round factorization as pivot rows may change |
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42 | Will be empty unless steepest edge (will save model) |
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43 | May also recompute infeasibility stuff |
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44 | 1) before factorization |
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45 | 2) after good factorization (if weights empty may initialize) |
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46 | 3) after something happened but no factorization |
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47 | (e.g. check for infeasible) |
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48 | 4) as 2 but restore weights from previous snapshot |
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49 | 5) for strong branching - initialize , infeasibilities |
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50 | */ |
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51 | virtual void saveWeights(AbcSimplex *model, int mode); |
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52 | /// Recompute infeasibilities |
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53 | virtual void recomputeInfeasibilities(); |
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54 | //@} |
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55 | |
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56 | ///@name Constructors and destructors |
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57 | //@{ |
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58 | /// Default Constructor |
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59 | AbcDualRowDantzig(); |
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60 | |
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61 | /// Copy constructor |
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62 | AbcDualRowDantzig(const AbcDualRowDantzig &); |
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63 | |
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64 | /// Assignment operator |
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65 | AbcDualRowDantzig &operator=(const AbcDualRowDantzig &rhs); |
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66 | |
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67 | /// Destructor |
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68 | virtual ~AbcDualRowDantzig(); |
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69 | |
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70 | /// Clone |
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71 | virtual AbcDualRowPivot *clone(bool copyData = true) const; |
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72 | |
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73 | //@} |
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74 | |
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75 | //--------------------------------------------------------------------------- |
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76 | |
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77 | private: |
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78 | ///@name Private member data |
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79 | /// infeasibility array (just for infeasible rows) |
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80 | CoinIndexedVector *infeasible_; |
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81 | //@} |
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82 | }; |
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83 | |
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84 | #endif |
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85 | |
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86 | /* vi: softtabstop=2 shiftwidth=2 expandtab tabstop=2 |
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87 | */ |
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