1 | // Copyright (C) 2002, International Business Machines |
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2 | // Corporation and others. All Rights Reserved. |
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3 | /* |
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4 | Authors |
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5 | |
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6 | Jeremy Omer |
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7 | |
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8 | Last update: april 10, 2015 |
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9 | |
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10 | */ |
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11 | |
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12 | #ifndef ClpPEDualRowSteepest_H |
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13 | #define ClpPEDualRowSteepest_H |
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14 | |
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15 | #include "ClpDualRowSteepest.hpp" |
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16 | #include "ClpPESimplex.hpp" |
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17 | class CoinIndexedVector; |
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18 | |
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19 | //############################################################################# |
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20 | |
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21 | /** Dual Row Pivot Steepest Edge Algorithm Class |
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22 | |
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23 | See Forrest-Goldfarb paper for algorithm |
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24 | |
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25 | */ |
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26 | |
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27 | class ClpPEDualRowSteepest : public ClpDualRowSteepest { |
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28 | |
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29 | public: |
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30 | /** Default Constructor |
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31 | mode: 0 is uninitialized, 1 full, 2 is partial uninitialized, |
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32 | 3 starts as 2 but may switch to 1. |
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33 | By partial is meant that the weights are updated as normal |
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34 | but only part of the infeasible basic variables are scanned. |
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35 | This can be faster on very easy problems. |
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36 | */ |
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37 | ClpPEDualRowSteepest(double psi = 0.5, int mode = 3); |
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38 | |
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39 | /// Copy constructor |
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40 | ClpPEDualRowSteepest(const ClpPEDualRowSteepest &); |
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41 | |
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42 | /// Assignment operator |
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43 | ClpPEDualRowSteepest &operator=(const ClpPEDualRowSteepest &rhs); |
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44 | |
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45 | /// Destructor |
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46 | virtual ~ClpPEDualRowSteepest(); |
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47 | |
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48 | /// Clone |
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49 | virtual ClpDualRowPivot *clone(bool copyData = true) const; |
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50 | |
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51 | public: |
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52 | ///@name Algorithmic methods |
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53 | //@{ |
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54 | |
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55 | /// Returns pivot row, -1 if none |
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56 | virtual int pivotRow(); |
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57 | |
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58 | /** Save weights - this may initialize weights as well |
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59 | This is as parent but may initialize ClpPESimplex |
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60 | */ |
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61 | virtual void saveWeights(ClpSimplex *model, int mode); |
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62 | /** Updates primal solution (and maybe list of candidates) |
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63 | Uses input vector which it deletes |
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64 | Computes change in objective function |
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65 | As ordinary steepest but checks for zero moves |
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66 | */ |
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67 | virtual void updatePrimalSolution(CoinIndexedVector *input, |
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68 | double theta, |
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69 | double &changeInObjective); |
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70 | //@} |
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71 | |
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72 | // Psi |
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73 | inline double psi() const |
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74 | { |
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75 | return psi_; |
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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 | private: |
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81 | /* this PESimplex object is used to identify the compatible variables */ |
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82 | ClpPESimplex *modelPE_; |
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83 | |
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84 | /* psi is the factor used in the bi-dimensional pricing, it is < 1 and |
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85 | 1/psi grows with the priority given to compatible variables */ |
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86 | double psi_; |
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87 | |
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88 | /* useful counters for the update of the set of compatible variables */ |
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89 | int iCurrent_; |
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90 | int iInterval_; |
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91 | |
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92 | /* record if previous iterations concluded that compatibles should not be checked */ |
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93 | bool updateCompatibles_; |
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94 | int coDegenCompatibles_, coConsecutiveCompatibles_; |
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95 | }; |
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96 | |
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97 | #endif |
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98 | |
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99 | /* vi: softtabstop=2 shiftwidth=2 expandtab tabstop=2 |
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100 | */ |
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