1 | // $Id: CbcBranchToFixLots.hpp 1854 2013-01-28 00:02:55Z stefan $ |
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2 | // Copyright (C) 2004, International Business Machines |
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3 | // Corporation and others. 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 | // Edwin 11/13/2009-- carved out of CbcBranchCut |
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7 | |
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8 | #ifndef CbcBranchToFixLots_H |
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9 | #define CbcBranchToFixLots_H |
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10 | |
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11 | #include "CbcBranchCut.hpp" |
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12 | #include "CbcBranchBase.hpp" |
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13 | #include "OsiRowCut.hpp" |
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14 | #include "CoinPackedMatrix.hpp" |
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15 | |
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16 | /** Define a branch class that branches so that one way variables are fixed |
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17 | while the other way cuts off that solution. |
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18 | a) On reduced cost |
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19 | b) When enough ==1 or <=1 rows have been satisfied (not fixed - satisfied) |
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20 | */ |
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21 | |
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22 | |
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23 | class CbcBranchToFixLots : public CbcBranchCut { |
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24 | |
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25 | public: |
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26 | |
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27 | // Default Constructor |
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28 | CbcBranchToFixLots (); |
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29 | |
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30 | /** Useful constructor - passed reduced cost tolerance and fraction we would like fixed. |
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31 | Also depth level to do at. |
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32 | Also passed number of 1 rows which when clean triggers fix |
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33 | Always does if all 1 rows cleaned up and number>0 or if fraction columns reached |
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34 | Also whether to create branch if can't reach fraction. |
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35 | */ |
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36 | CbcBranchToFixLots (CbcModel * model, double djTolerance, |
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37 | double fractionFixed, int depth, |
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38 | int numberClean = 0, |
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39 | const char * mark = NULL, |
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40 | bool alwaysCreate = false); |
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41 | |
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42 | // Copy constructor |
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43 | CbcBranchToFixLots ( const CbcBranchToFixLots &); |
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44 | |
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45 | /// Clone |
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46 | virtual CbcObject * clone() const; |
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47 | |
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48 | // Assignment operator |
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49 | CbcBranchToFixLots & operator=( const CbcBranchToFixLots& rhs); |
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50 | |
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51 | // Destructor |
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52 | ~CbcBranchToFixLots (); |
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53 | |
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54 | /** Does a lot of the work, |
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55 | Returns 0 if no good, 1 if dj, 2 if clean, 3 if both |
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56 | FIXME: should use enum or equivalent to make these numbers clearer. |
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57 | */ |
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58 | int shallWe() const; |
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59 | |
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60 | /// Infeasibility for an integer variable - large is 0.5, but also can be infinity when known infeasible. |
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61 | virtual double infeasibility(const OsiBranchingInformation * info, |
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62 | int &preferredWay) const; |
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63 | /** \brief Return true if object can take part in normal heuristics |
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64 | */ |
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65 | virtual bool canDoHeuristics() const { |
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66 | return true; |
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67 | } |
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68 | |
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69 | /// Creates a branching object |
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70 | virtual CbcBranchingObject * createCbcBranch(OsiSolverInterface * solver, const OsiBranchingInformation * info, int way) ; |
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71 | /// Redoes data when sequence numbers change |
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72 | virtual void redoSequenceEtc(CbcModel * model, int numberColumns, const int * originalColumns); |
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73 | |
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74 | |
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75 | protected: |
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76 | /// data |
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77 | |
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78 | /// Reduced cost tolerance i.e. dj has to be >= this before fixed |
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79 | double djTolerance_; |
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80 | /// We only need to make sure this fraction fixed |
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81 | double fractionFixed_; |
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82 | /// Never fix ones marked here |
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83 | char * mark_; |
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84 | /// Matrix by row |
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85 | CoinPackedMatrix matrixByRow_; |
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86 | /// Do if depth multiple of this |
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87 | int depth_; |
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88 | /// number of ==1 rows which need to be clean |
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89 | int numberClean_; |
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90 | /// If true then always create branch |
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91 | bool alwaysCreate_; |
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92 | }; |
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93 | #endif |
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94 | |
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