1 | /* $Id: ClpDualRowSteepest.hpp 1525 2010-02-26 17:27:59Z mjs $ */ |
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2 | // Copyright (C) 2002, International Business Machines |
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3 | // Corporation and others. All Rights Reserved. |
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4 | #ifndef ClpDualRowSteepest_H |
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5 | #define ClpDualRowSteepest_H |
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6 | |
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7 | #include "ClpDualRowPivot.hpp" |
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8 | class CoinIndexedVector; |
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9 | |
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10 | |
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11 | //############################################################################# |
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12 | |
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13 | /** Dual Row Pivot Steepest Edge Algorithm Class |
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14 | |
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15 | See Forrest-Goldfarb paper for algorithm |
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16 | |
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17 | */ |
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18 | |
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19 | class ClpDualRowSteepest : public ClpDualRowPivot { |
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20 | |
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21 | public: |
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22 | |
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23 | ///@name Algorithmic methods |
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24 | //@{ |
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25 | |
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26 | /// Returns pivot row, -1 if none |
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27 | virtual int pivotRow(); |
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28 | |
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29 | /** Updates weights and returns pivot alpha. |
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30 | Also does FT update */ |
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31 | virtual double updateWeights(CoinIndexedVector * input, |
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32 | CoinIndexedVector * spare, |
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33 | CoinIndexedVector * spare2, |
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34 | CoinIndexedVector * updatedColumn); |
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35 | |
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36 | /** Updates primal solution (and maybe list of candidates) |
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37 | Uses input vector which it deletes |
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38 | Computes change in objective function |
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39 | */ |
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40 | virtual void updatePrimalSolution(CoinIndexedVector * input, |
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41 | double theta, |
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42 | double & changeInObjective); |
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43 | |
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44 | /** Saves any weights round factorization as pivot rows may change |
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45 | Save model |
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46 | May also recompute infeasibility stuff |
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47 | 1) before factorization |
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48 | 2) after good factorization (if weights empty may initialize) |
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49 | 3) after something happened but no factorization |
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50 | (e.g. check for infeasible) |
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51 | 4) as 2 but restore weights from previous snapshot |
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52 | 5) for strong branching - initialize (uninitialized) , infeasibilities |
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53 | */ |
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54 | virtual void saveWeights(ClpSimplex * model, int mode); |
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55 | /// Gets rid of last update |
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56 | virtual void unrollWeights(); |
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57 | /// Gets rid of all arrays |
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58 | virtual void clearArrays(); |
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59 | /// Returns true if would not find any row |
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60 | virtual bool looksOptimal() const; |
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61 | /// Called when maximum pivots changes |
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62 | virtual void maximumPivotsChanged(); |
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63 | //@} |
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64 | |
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65 | /** enums for persistence |
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66 | */ |
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67 | enum Persistence { |
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68 | normal = 0x00, // create (if necessary) and destroy |
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69 | keep = 0x01 // create (if necessary) and leave |
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70 | }; |
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71 | |
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72 | ///@name Constructors and destructors |
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73 | //@{ |
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74 | /** Default Constructor |
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75 | 0 is uninitialized, 1 full, 2 is partial uninitialized, |
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76 | 3 starts as 2 but may switch to 1. |
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77 | By partial is meant that the weights are updated as normal |
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78 | but only part of the infeasible basic variables are scanned. |
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79 | This can be faster on very easy problems. |
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80 | */ |
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81 | ClpDualRowSteepest(int mode = 3); |
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82 | |
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83 | /// Copy constructor |
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84 | ClpDualRowSteepest(const ClpDualRowSteepest &); |
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85 | |
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86 | /// Assignment operator |
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87 | ClpDualRowSteepest & operator=(const ClpDualRowSteepest& rhs); |
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88 | |
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89 | /// Fill most values |
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90 | void fill(const ClpDualRowSteepest& rhs); |
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91 | |
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92 | /// Destructor |
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93 | virtual ~ClpDualRowSteepest (); |
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94 | |
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95 | /// Clone |
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96 | virtual ClpDualRowPivot * clone(bool copyData = true) const; |
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97 | |
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98 | //@} |
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99 | /**@name gets and sets */ |
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100 | //@{ |
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101 | /// Mode |
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102 | inline int mode() const { |
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103 | return mode_; |
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104 | } |
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105 | /// Set/ get persistence |
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106 | inline void setPersistence(Persistence life) { |
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107 | persistence_ = life; |
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108 | } |
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109 | inline Persistence persistence() const { |
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110 | return persistence_ ; |
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111 | } |
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112 | //@} |
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113 | |
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114 | //--------------------------------------------------------------------------- |
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115 | |
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116 | private: |
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117 | ///@name Private member data |
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118 | /** Status |
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119 | 0) Normal |
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120 | -1) Needs initialization |
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121 | 1) Weights are stored by sequence number |
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122 | */ |
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123 | int state_; |
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124 | /** If 0 then we are using uninitialized weights, 1 then full, |
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125 | if 2 then uninitialized partial, 3 switchable */ |
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126 | int mode_; |
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127 | /// Life of weights |
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128 | Persistence persistence_; |
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129 | /// weight array |
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130 | double * weights_; |
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131 | /// square of infeasibility array (just for infeasible rows) |
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132 | CoinIndexedVector * infeasible_; |
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133 | /// alternate weight array (so we can unroll) |
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134 | CoinIndexedVector * alternateWeights_; |
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135 | /// save weight array (so we can use checkpoint) |
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136 | CoinIndexedVector * savedWeights_; |
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137 | /// Dubious weights |
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138 | int * dubiousWeights_; |
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139 | //@} |
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140 | }; |
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141 | |
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142 | #endif |
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