1 | /* -*- C++ -*- |
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2 | * |
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3 | * This file is a part of LEMON, a generic C++ optimization library |
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4 | * |
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5 | * Copyright (C) 2003-2008 |
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6 | * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
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7 | * (Egervary Research Group on Combinatorial Optimization, EGRES). |
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8 | * |
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9 | * Permission to use, modify and distribute this software is granted |
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10 | * provided that this copyright notice appears in all copies. For |
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11 | * precise terms see the accompanying LICENSE file. |
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12 | * |
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13 | * This software is provided "AS IS" with no warranty of any kind, |
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14 | * express or implied, and with no claim as to its suitability for any |
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15 | * purpose. |
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16 | * |
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17 | */ |
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18 | |
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19 | #ifndef LEMON_LP_UTILS_H |
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20 | #define LEMON_LP_UTILS_H |
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21 | |
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22 | #include <lemon/lp_base.h> |
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23 | |
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24 | #include <lemon/lemon_reader.h> |
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25 | #include <lemon/lemon_writer.h> |
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26 | |
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27 | #include <map> |
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28 | #include <set> |
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29 | |
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30 | |
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31 | namespace lemon { |
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32 | |
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33 | /// \ingroup lp_utils |
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34 | /// |
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35 | /// \brief The map for the result of the lp variables. |
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36 | /// |
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37 | /// The map for the result of the lp variables. |
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38 | class LpResultMap { |
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39 | public: |
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40 | typedef LpSolverBase::Col Key; |
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41 | typedef LpSolverBase::Value Value; |
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42 | |
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43 | /// \brief Constructor |
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44 | /// |
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45 | /// Constructor |
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46 | LpResultMap(const LpSolverBase& _lp) : lp(_lp) {} |
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47 | LpSolverBase::Value operator[](const LpSolverBase::Col col) const { |
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48 | return lp.primal(col); |
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49 | } |
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50 | private: |
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51 | const LpSolverBase& lp; |
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52 | }; |
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53 | |
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54 | /// \ingroup lp_utils |
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55 | /// |
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56 | /// \brief Returns an \ref LpResultMap class |
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57 | /// |
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58 | /// This function just returns an \ref LpResultMap class. |
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59 | /// \relates LpResultMap |
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60 | LpResultMap lpResultMap(const LpSolverBase& lp) { |
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61 | return LpResultMap(lp); |
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62 | } |
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63 | |
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64 | /// \ingroup lp_utils |
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65 | /// |
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66 | /// \brief The map for the name of the lp variables. |
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67 | /// |
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68 | /// The map for the name of the lp variables. |
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69 | class LpColNameMap { |
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70 | public: |
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71 | typedef LpSolverBase::Col Key; |
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72 | typedef std::string Value; |
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73 | |
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74 | /// \brief Constructor |
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75 | /// |
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76 | /// Constructor |
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77 | LpColNameMap(const LpSolverBase& _lp) : lp(_lp) {} |
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78 | std::string operator[](const LpSolverBase::Col col) const { |
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79 | return lp.colName(col); |
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80 | } |
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81 | private: |
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82 | const LpSolverBase& lp; |
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83 | }; |
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84 | |
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85 | /// \ingroup lp_utils |
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86 | /// |
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87 | /// \brief Writeable map for the name of the lp variables. |
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88 | /// |
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89 | /// Writeable map for the name of the lp variables. |
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90 | class LpColNameWriteMap { |
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91 | public: |
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92 | typedef LpSolverBase::Col Key; |
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93 | typedef std::string Value; |
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94 | |
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95 | /// \brief Constructor |
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96 | /// |
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97 | /// Constructor |
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98 | LpColNameWriteMap(LpSolverBase& _lp) : lp(_lp) {} |
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99 | std::string operator[](const LpSolverBase::Col col) const { |
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100 | return lp.colName(col); |
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101 | } |
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102 | void set(const LpSolverBase::Col col, const std::string& name) { |
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103 | lp.colName(col, name); |
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104 | } |
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105 | private: |
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106 | LpSolverBase& lp; |
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107 | }; |
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108 | |
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109 | /// \ingroup lp_utils |
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110 | /// |
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111 | /// \brief Returns an \ref LpColNameMap class |
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112 | /// |
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113 | /// This function just returns an \ref LpColNameMap class. |
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114 | /// \relates LpColNameMap |
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115 | LpColNameMap lpColNameMap(const LpSolverBase& lp) { |
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116 | return LpColNameMap(lp); |
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117 | } |
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118 | |
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119 | LpColNameWriteMap lpColNameMap(LpSolverBase& lp) { |
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120 | return LpColNameWriteMap(lp); |
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121 | } |
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122 | |
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123 | /// \ingroup lp_utils |
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124 | /// |
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125 | /// \brief Lp variable item reader for Lemon IO |
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126 | /// |
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127 | /// This class is an Lp variable item reader for Lemon IO. It makes |
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128 | /// possible to store lp variables in lemon file. The usage of this |
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129 | /// class is very simple: |
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130 | /// |
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131 | ///\code |
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132 | /// Graph graph; |
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133 | /// Lp lp; |
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134 | /// Graph::EdgeMap<Lp::Col> var(graph); |
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135 | /// |
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136 | /// GraphReader<Graph> reader(cin, graph); |
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137 | /// reader.readEdgeMap("lpvar", var, LpColReader(lp)); |
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138 | /// reader.run(); |
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139 | ///\endcode |
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140 | /// |
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141 | /// If there is already a variable with the same name in the lp then |
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142 | /// it will be used for the return value. If there is no such variable |
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143 | /// then it will be constructed. The file could contain \c '-' as value |
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144 | /// which means that no lp variable associated to the current item and |
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145 | /// in this case INVALID will be returned. |
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146 | class LpColReader { |
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147 | public: |
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148 | |
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149 | /// \brief The value type of reader. |
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150 | /// |
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151 | /// The value type of reader. |
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152 | typedef LpSolverBase::Col Value; |
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153 | |
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154 | /// \brief Constructor for the reader. |
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155 | /// |
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156 | /// Constructor for the reader. |
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157 | LpColReader(LpSolverBase& _lp) : lp(_lp) {} |
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158 | |
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159 | /// \brief Reads an lp variable from the given stream. |
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160 | /// |
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161 | /// Reads an lp variable string from the given stream. |
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162 | void read(std::istream& is, LpSolverBase::Col& col) const { |
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163 | char x; |
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164 | is >> std::ws; |
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165 | if (!is.get(x)) |
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166 | throw DataFormatError("Wrong Lp Column format!"); |
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167 | if (varFirstChar(x)) { |
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168 | std::string var; |
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169 | var += x; |
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170 | |
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171 | while (is.get(x) && varChar(x)) { |
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172 | var += x; |
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173 | } |
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174 | if (!is) { |
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175 | is.clear(); |
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176 | } else { |
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177 | is.putback(x); |
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178 | } |
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179 | col = lp.colByName(var); |
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180 | if (col == INVALID) { |
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181 | col = lp.addCol(); |
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182 | lp.colName(col, var); |
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183 | } |
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184 | } else if (x == '-') { |
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185 | col = INVALID; |
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186 | is >> std::ws; |
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187 | } else { |
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188 | std::cerr << x << std::endl; |
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189 | throw DataFormatError("Wrong Lp Column format"); |
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190 | } |
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191 | } |
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192 | |
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193 | private: |
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194 | |
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195 | static bool varFirstChar(char c) { |
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196 | return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z'); |
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197 | } |
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198 | |
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199 | static bool varChar(char c) { |
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200 | return (c >= '0' && c <= '9') || |
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201 | (c >= 'a' && c <= 'z') || |
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202 | (c >= 'A' && c <= 'Z') || |
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203 | c == '[' || c == ']'; |
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204 | } |
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205 | |
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206 | LpSolverBase& lp; |
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207 | |
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208 | }; |
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209 | |
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210 | /// \ingroup lp_utils |
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211 | /// |
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212 | /// \brief Lp variable item writer for Lemon IO |
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213 | /// |
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214 | /// This class is an Lp variable item writer for Lemon IO. It makes |
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215 | /// possible to store lp variables in lemon file. The usage of this |
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216 | /// class is very simple: |
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217 | /// |
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218 | ///\code |
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219 | /// Graph graph; |
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220 | /// Lp lp; |
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221 | /// Graph::EdgeMap<Lp::Col> var(graph); |
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222 | /// |
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223 | /// GraphWriter<Graph> writer(cin, graph); |
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224 | /// writer.writeEdgeMap("lpvar", var, LpColWriter(lp)); |
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225 | /// writer.run(); |
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226 | ///\endcode |
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227 | /// |
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228 | /// If there is no name associated to the current item then the name |
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229 | /// will automatically constructed. If the value is INVALID then it |
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230 | /// will write an \c '-' value to the file. |
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231 | class LpColWriter { |
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232 | public: |
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233 | |
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234 | /// \brief The value type of writer. |
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235 | /// |
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236 | /// The value type of writer. |
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237 | typedef LpSolverBase::Col Value; |
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238 | |
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239 | /// \brief Constructor for the writer. |
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240 | /// |
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241 | /// Constructor for the writer. |
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242 | LpColWriter(const LpSolverBase& _lp) : lp(_lp), num(0) {} |
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243 | |
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244 | /// \brief Writes an lp variable to the given stream. |
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245 | /// |
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246 | /// Writes an lp variable to the given stream. |
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247 | void write(std::ostream& os, const LpSolverBase::Col& col) const { |
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248 | if (col != INVALID) { |
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249 | std::string name = lp.colName(col); |
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250 | if (name.empty()) { |
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251 | std::ostringstream ls; |
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252 | ls << "x" << num; |
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253 | ++num; |
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254 | while (lp.colByName(ls.str()) != INVALID) { |
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255 | ls.str(std::string()); |
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256 | ls << "x" << num; |
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257 | ++num; |
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258 | } |
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259 | const_cast<LpSolverBase&>(lp).colName(col, ls.str()); |
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260 | os << ls.str(); |
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261 | } else { |
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262 | os << name; |
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263 | } |
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264 | } else { |
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265 | os << "-"; |
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266 | } |
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267 | } |
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268 | |
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269 | private: |
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270 | |
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271 | const LpSolverBase& lp; |
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272 | mutable int num; |
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273 | |
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274 | }; |
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275 | |
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276 | /// \ingroup lp_utils |
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277 | /// |
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278 | /// \brief Lp section reader for lemon IO |
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279 | /// |
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280 | /// This section reader provides an easy way to read an Lp problem |
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281 | /// from a file. The lemon lp section format contains three parts. |
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282 | /// |
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283 | ///\code |
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284 | /// @lp |
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285 | /// constraints |
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286 | /// 7 == x1 - 1 * x2 |
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287 | /// 2 * x1 + x3 / 2 <= 7 |
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288 | /// x2 + -3 * x3 >= 8 |
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289 | /// 3 <= x2 - 2 * x1 <= 8 |
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290 | /// bounds |
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291 | /// x1 >= 3 |
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292 | /// 2 <= x2 <= 5 |
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293 | /// 0 <= x3 <= 8 |
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294 | /// objective |
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295 | /// min x1 + 2 * x2 - x3 |
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296 | ///\endcode |
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297 | /// |
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298 | /// The first part gives the constraints to the lp. The constraints |
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299 | /// could be equality, lower bound, upper bound or range for an |
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300 | /// expression or equality, less or more for two expressions. |
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301 | /// |
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302 | /// The second part gives the bounds for the variables. The bounds |
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303 | /// could be the same as for the single expression so equality, |
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304 | /// lower bound, upper bound or range. |
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305 | /// |
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306 | /// The third part is the objective function, it should start with |
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307 | /// \c min or \c max and then a valid linear expression. |
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308 | /// |
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309 | /// The reader constructs automatically the variable for a name if |
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310 | /// there is not already a variable with the same name. |
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311 | /// |
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312 | /// The basic way to read an LP problem is made by the next code: |
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313 | ///\code |
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314 | /// Lp lp; |
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315 | /// |
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316 | /// LemonReader reader(filename_or_istream); |
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317 | /// LpReader lpreader(reader, lp); |
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318 | /// |
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319 | /// reader.run(); |
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320 | ///\endcode |
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321 | /// |
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322 | /// Of course instead of \c LemonReader you can give a \c |
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323 | /// GraphReader to the LpReader constructor. Also useful that you |
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324 | /// can mix lp problems and graphs in the same file. |
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325 | class LpReader : public LemonReader::SectionReader { |
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326 | typedef LemonReader::SectionReader Parent; |
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327 | public: |
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328 | |
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329 | |
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330 | /// \brief Constructor. |
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331 | /// |
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332 | /// Constructor for LpReader. It creates the LpReader and attachs |
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333 | /// it into the given LemonReader. The lp reader will add |
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334 | /// variables, constraints and objective function to the |
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335 | /// given lp solver. |
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336 | LpReader(LemonReader& _reader, LpSolverBase& _lp, |
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337 | const std::string& _name = std::string()) |
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338 | : Parent(_reader), lp(_lp), name(_name) {} |
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339 | |
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340 | |
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341 | /// \brief Destructor. |
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342 | /// |
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343 | /// Destructor for LpReader. |
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344 | virtual ~LpReader() {} |
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345 | |
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346 | private: |
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347 | LpReader(const LpReader&); |
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348 | void operator=(const LpReader&); |
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349 | |
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350 | protected: |
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351 | |
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352 | /// \brief Gives back true when the SectionReader can process |
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353 | /// the section with the given header line. |
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354 | /// |
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355 | /// It gives back true when the header line starts with \c \@lp, |
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356 | /// and the header line's name and the nodeset's name are the same. |
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357 | virtual bool header(const std::string& line) { |
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358 | std::istringstream ls(line); |
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359 | std::string command; |
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360 | std::string id; |
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361 | ls >> command >> id; |
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362 | return command == "@lp" && name == id; |
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363 | } |
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364 | |
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365 | private: |
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366 | |
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367 | enum Part { |
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368 | CONSTRAINTS, BOUNDS, OBJECTIVE |
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369 | }; |
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370 | |
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371 | enum Relation { |
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372 | LE, EQ, GE |
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373 | }; |
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374 | |
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375 | std::istream& readConstraint(std::istream& is) { |
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376 | LpSolverBase::Constr c; |
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377 | char x; |
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378 | LpSolverBase::Expr e1, e2; |
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379 | Relation op1; |
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380 | is >> std::ws; |
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381 | readExpression(is, e1); |
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382 | is >> std::ws; |
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383 | readRelation(is, op1); |
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384 | is >> std::ws; |
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385 | readExpression(is, e2); |
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386 | is >> std::ws; |
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387 | if (!is.get(x)) { |
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388 | if (op1 == LE) { |
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389 | if (e1.size() == 0) { |
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390 | c = e2 >= e1; |
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391 | } else { |
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392 | c = e1 <= e2; |
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393 | } |
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394 | c = e1 <= e2; |
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395 | } else if (op1 == GE) { |
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396 | if (e1.size() == 0) { |
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397 | c = e2 <= e1; |
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398 | } else { |
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399 | c = e1 >= e2; |
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400 | } |
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401 | } else { |
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402 | if (e1.size() == 0) { |
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403 | c = e2 == e1; |
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404 | } else { |
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405 | c = e1 == e2; |
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406 | } |
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407 | } |
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408 | } else { |
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409 | is.putback(x); |
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410 | LpSolverBase::Expr e3; |
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411 | Relation op2; |
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412 | readRelation(is, op2); |
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413 | is >> std::ws; |
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414 | readExpression(is, e3); |
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415 | if (!e1.empty() || !e3.empty()) { |
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416 | throw DataFormatError("Wrong range format"); |
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417 | } |
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418 | if (op2 != op1 || op1 == EQ) { |
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419 | throw DataFormatError("Wrong range format"); |
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420 | } |
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421 | if (op1 == LE) { |
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422 | c = e1.constComp() <= e2 <= e3.constComp(); |
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423 | } else { |
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424 | c = e1.constComp() >= e2 >= e3.constComp(); |
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425 | } |
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426 | is >> std::ws; |
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427 | if (is.get(x)) { |
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428 | throw DataFormatError("Wrong variable bounds format"); |
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429 | } |
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430 | } |
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431 | lp.addRow(c); |
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432 | return is; |
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433 | } |
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434 | |
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435 | std::istream& readObjective(std::istream& is) { |
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436 | is >> std::ws; |
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437 | std::string sense; |
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438 | is >> sense; |
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439 | if (sense != "min" && sense != "max") { |
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440 | throw DataFormatError("Wrong objective function format"); |
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441 | } |
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442 | LpSolverBase::Expr expr; |
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443 | is >> std::ws; |
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444 | readExpression(is, expr); |
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445 | lp.obj(expr); |
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446 | if (sense == "min") { |
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447 | lp.min(); |
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448 | } else { |
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449 | lp.max(); |
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450 | } |
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451 | return is; |
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452 | } |
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453 | |
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454 | std::istream& readBounds(std::istream& is) { |
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455 | LpSolverBase::Col c; |
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456 | char x; |
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457 | is >> std::ws; |
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458 | if (!is.get(x)) { |
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459 | throw DataFormatError("Wrong variable bounds format"); |
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460 | } |
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461 | if (varFirstChar(x)) { |
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462 | is.putback(x); |
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463 | readCol(is, c); |
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464 | is >> std::ws; |
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465 | Relation op1; |
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466 | readRelation(is, op1); |
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467 | double v; |
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468 | readNum(is, v); |
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469 | if (op1 == EQ) { |
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470 | lp.colLowerBound(c, v); |
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471 | lp.colUpperBound(c, v); |
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472 | } else if (op1 == LE) { |
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473 | lp.colUpperBound(c, v); |
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474 | } else { |
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475 | lp.colLowerBound(c, v); |
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476 | } |
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477 | is >> std::ws; |
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478 | if (is.get(x)) { |
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479 | throw DataFormatError("Wrong variable bounds format"); |
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480 | } |
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481 | } else { |
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482 | is.putback(x); |
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483 | double v; |
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484 | readNum(is, v); |
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485 | is >> std::ws; |
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486 | Relation op1; |
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487 | readRelation(is, op1); |
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488 | is >> std::ws; |
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489 | readCol(is, c); |
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490 | is >> std::ws; |
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491 | if (is.get(x)) { |
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492 | is.putback(x); |
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493 | is >> std::ws; |
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494 | Relation op2; |
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495 | readRelation(is, op2); |
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496 | double w; |
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497 | is >> std::ws; |
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498 | readNum(is, w); |
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499 | if (op2 != op1 || op1 == EQ) { |
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500 | throw DataFormatError("Wrong range format"); |
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501 | } |
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502 | if (op1 == LE) { |
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503 | lp.colLowerBound(c, v); |
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504 | lp.colUpperBound(c, w); |
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505 | } else { |
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506 | lp.colLowerBound(c, w); |
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507 | lp.colUpperBound(c, v); |
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508 | } |
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509 | is >> std::ws; |
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510 | if (is.get(x)) { |
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511 | throw DataFormatError("Wrong variable bounds format"); |
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512 | } |
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513 | } else { |
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514 | if (op1 == EQ) { |
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515 | lp.colLowerBound(c, v); |
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516 | lp.colUpperBound(c, v); |
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517 | } else if (op1 == LE) { |
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518 | lp.colLowerBound(c, v); |
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519 | } else { |
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520 | lp.colUpperBound(c, v); |
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521 | } |
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522 | } |
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523 | } |
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524 | return is; |
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525 | } |
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526 | |
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527 | std::istream& readExpression(std::istream& is, LpSolverBase::Expr& e) { |
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528 | LpSolverBase::Col c; |
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529 | double d; |
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530 | char x; |
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531 | readElement(is, c, d); |
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532 | if (c != INVALID) { |
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533 | e += d * c; |
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534 | } else { |
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535 | e += d; |
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536 | } |
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537 | is >> std::ws; |
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538 | while (is.get(x) && (x == '+' || x == '-')) { |
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539 | is >> std::ws; |
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540 | readElement(is, c, d); |
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541 | if (c != INVALID) { |
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542 | e += (x == '+' ? d : -d) * c; |
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543 | } else { |
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544 | e += (x == '+' ? d : -d); |
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545 | } |
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546 | is >> std::ws; |
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547 | } |
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548 | if (!is) { |
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549 | is.clear(); |
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550 | } else { |
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551 | is.putback(x); |
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552 | } |
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553 | return is; |
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554 | } |
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555 | |
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556 | std::istream& readElement(std::istream& is, |
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557 | LpSolverBase::Col& c, double& d) { |
---|
558 | d = 1.0; |
---|
559 | c = INVALID; |
---|
560 | char x, y; |
---|
561 | if (!is.get(x)) throw DataFormatError("Cannot find lp element"); |
---|
562 | if (x == '+' || x == '-') { |
---|
563 | is >> std::ws; |
---|
564 | d *= x == '-' ? -1 : 1; |
---|
565 | while (is.get(x) && (x == '+' || x == '-')) { |
---|
566 | d *= x == '-' ? -1 : 1; |
---|
567 | is >> std::ws; |
---|
568 | } |
---|
569 | if (!is) throw DataFormatError("Cannot find lp element"); |
---|
570 | } |
---|
571 | if (numFirstChar(x)) { |
---|
572 | is.putback(x); |
---|
573 | double e; |
---|
574 | readNum(is, e); |
---|
575 | d *= e; |
---|
576 | } else if (varFirstChar(x)) { |
---|
577 | is.putback(x); |
---|
578 | LpSolverBase::Col f; |
---|
579 | readCol(is, f); |
---|
580 | c = f; |
---|
581 | } else { |
---|
582 | throw DataFormatError("Invalid expression format"); |
---|
583 | } |
---|
584 | is >> std::ws; |
---|
585 | while (is.get(y) && (y == '*' || y == '/')) { |
---|
586 | is >> std::ws; |
---|
587 | if (!is.get(x)) throw DataFormatError("Cannot find lp element"); |
---|
588 | if (x == '+' || x == '-') { |
---|
589 | is >> std::ws; |
---|
590 | d *= x == '-' ? -1 : 1; |
---|
591 | while (is.get(x) && (x == '+' || x == '-')) { |
---|
592 | d *= x == '-' ? -1 : 1; |
---|
593 | is >> std::ws; |
---|
594 | } |
---|
595 | if (!is) throw DataFormatError("Cannot find lp element"); |
---|
596 | } |
---|
597 | if (numFirstChar(x)) { |
---|
598 | is.putback(x); |
---|
599 | double e; |
---|
600 | readNum(is, e); |
---|
601 | if (y == '*') { |
---|
602 | d *= e; |
---|
603 | } else { |
---|
604 | d /= e; |
---|
605 | } |
---|
606 | } else if (varFirstChar(x)) { |
---|
607 | is.putback(x); |
---|
608 | LpSolverBase::Col f; |
---|
609 | readCol(is, f); |
---|
610 | if (y == '*') { |
---|
611 | if (c == INVALID) { |
---|
612 | c = f; |
---|
613 | } else { |
---|
614 | throw DataFormatError("Quadratic element in expression"); |
---|
615 | } |
---|
616 | } else { |
---|
617 | throw DataFormatError("Division by variable"); |
---|
618 | } |
---|
619 | } else { |
---|
620 | throw DataFormatError("Invalid expression format"); |
---|
621 | } |
---|
622 | is >> std::ws; |
---|
623 | } |
---|
624 | if (!is) { |
---|
625 | is.clear(); |
---|
626 | } else { |
---|
627 | is.putback(y); |
---|
628 | } |
---|
629 | return is; |
---|
630 | } |
---|
631 | |
---|
632 | std::istream& readCol(std::istream& is, LpSolverBase::Col& c) { |
---|
633 | char x; |
---|
634 | std::string var; |
---|
635 | while (is.get(x) && varChar(x)) { |
---|
636 | var += x; |
---|
637 | } |
---|
638 | if (!is) { |
---|
639 | is.clear(); |
---|
640 | } else { |
---|
641 | is.putback(x); |
---|
642 | } |
---|
643 | c = lp.colByName(var); |
---|
644 | if (c == INVALID) { |
---|
645 | c = lp.addCol(); |
---|
646 | lp.colName(c, var); |
---|
647 | } |
---|
648 | return is; |
---|
649 | } |
---|
650 | |
---|
651 | std::istream& readNum(std::istream& is, double& d) { |
---|
652 | is >> d; |
---|
653 | if (!is) throw DataFormatError("Wrong number format"); |
---|
654 | return is; |
---|
655 | } |
---|
656 | |
---|
657 | std::istream& readRelation(std::istream& is, Relation& op) { |
---|
658 | char x, y; |
---|
659 | if (!is.get(x) || !(x == '<' || x == '=' || x == '>')) { |
---|
660 | throw DataFormatError("Wrong relation operator"); |
---|
661 | } |
---|
662 | if (!is.get(y) || y != '=') { |
---|
663 | throw DataFormatError("Wrong relation operator"); |
---|
664 | } |
---|
665 | switch (x) { |
---|
666 | case '<': op = LE; |
---|
667 | break; |
---|
668 | case '=': op = EQ; |
---|
669 | break; |
---|
670 | case '>': op = GE; |
---|
671 | break; |
---|
672 | } |
---|
673 | return is; |
---|
674 | } |
---|
675 | |
---|
676 | static bool relationFirstChar(char c) { |
---|
677 | return c == '<' || c == '=' || c == '>'; |
---|
678 | } |
---|
679 | |
---|
680 | static bool varFirstChar(char c) { |
---|
681 | return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z'); |
---|
682 | } |
---|
683 | |
---|
684 | static bool numFirstChar(char c) { |
---|
685 | return (c >= '0' && c <= '9') || c == '.'; |
---|
686 | } |
---|
687 | |
---|
688 | static bool varChar(char c) { |
---|
689 | return (c >= '0' && c <= '9') || |
---|
690 | (c >= 'a' && c <= 'z') || |
---|
691 | (c >= 'A' && c <= 'Z') || |
---|
692 | c == '[' || c == ']'; |
---|
693 | } |
---|
694 | |
---|
695 | protected: |
---|
696 | |
---|
697 | /// \brief Reader function of the section. |
---|
698 | /// |
---|
699 | /// It reads the content of the section. |
---|
700 | virtual void read(std::istream& is) { |
---|
701 | std::string line; |
---|
702 | Part part = CONSTRAINTS; |
---|
703 | while (getline(is, line)) { |
---|
704 | std::istringstream ls(line); |
---|
705 | std::string type; |
---|
706 | ls >> type; |
---|
707 | if (type == "constraints") { |
---|
708 | part = CONSTRAINTS; |
---|
709 | ls >> std::ws; |
---|
710 | char x; |
---|
711 | if (ls.get(x)) |
---|
712 | throw DataFormatError("Wrong Lp format"); |
---|
713 | } else if (type == "bounds") { |
---|
714 | part = BOUNDS; |
---|
715 | ls >> std::ws; |
---|
716 | char x; |
---|
717 | if (ls.get(x)) |
---|
718 | throw DataFormatError("Wrong Lp format"); |
---|
719 | } else if (type == "objective") { |
---|
720 | part = OBJECTIVE; |
---|
721 | ls >> std::ws; |
---|
722 | char x; |
---|
723 | if (ls.get(x)) |
---|
724 | throw DataFormatError("Wrong Lp format"); |
---|
725 | } else { |
---|
726 | ls.str(line); |
---|
727 | switch (part) { |
---|
728 | case CONSTRAINTS: |
---|
729 | readConstraint(ls); |
---|
730 | break; |
---|
731 | case BOUNDS: |
---|
732 | readBounds(ls); |
---|
733 | break; |
---|
734 | case OBJECTIVE: |
---|
735 | readObjective(ls); |
---|
736 | break; |
---|
737 | } |
---|
738 | } |
---|
739 | } |
---|
740 | } |
---|
741 | |
---|
742 | virtual void missing() { |
---|
743 | ErrorMessage msg; |
---|
744 | msg << "Lp section not found in file: @lp " << name; |
---|
745 | throw IoParameterError(msg.message()); |
---|
746 | } |
---|
747 | |
---|
748 | private: |
---|
749 | |
---|
750 | |
---|
751 | LpSolverBase& lp; |
---|
752 | std::string name; |
---|
753 | }; |
---|
754 | |
---|
755 | |
---|
756 | /// \ingroup lp_utils |
---|
757 | /// |
---|
758 | /// \brief Lp section writer for lemon IO |
---|
759 | /// |
---|
760 | /// This section reader provides an easy way to write an Lp problem |
---|
761 | /// to a file. The lemon lp section format contains three parts. |
---|
762 | /// |
---|
763 | ///\code |
---|
764 | /// @lp |
---|
765 | /// constraints |
---|
766 | /// 7 == x1 - 1 * x2 |
---|
767 | /// 2 * x1 + x3 / 2 <= 7 |
---|
768 | /// x2 + -3 * x3 >= 8 |
---|
769 | /// 3 <= x2 - 2 * x1 <= 8 |
---|
770 | /// bounds |
---|
771 | /// x1 >= 3 |
---|
772 | /// 2 <= x2 <= 5 |
---|
773 | /// 0 <= x3 <= 8 |
---|
774 | /// objective |
---|
775 | /// min x1 + 2 * x2 - x3 |
---|
776 | ///\endcode |
---|
777 | /// |
---|
778 | /// The first part gives the constraints to the lp. The constraints |
---|
779 | /// could be equality, lower bound, upper bound or range for an |
---|
780 | /// expression or equality, less or more for two expressions. |
---|
781 | /// |
---|
782 | /// The second part gives the bounds for the variables. The bounds |
---|
783 | /// could be the same as for the single expression so equality, |
---|
784 | /// lower bound, upper bound or range. |
---|
785 | /// |
---|
786 | /// The third part is the objective function, it should start with |
---|
787 | /// \c min or \c max and then a valid linear expression. |
---|
788 | /// |
---|
789 | /// If an LP variable does not have name in the writer, then it will |
---|
790 | /// automatically created in the writer. This make a slight change |
---|
791 | /// in the \c const variable. |
---|
792 | /// |
---|
793 | /// The basic way to write an LP problem is made by the next code: |
---|
794 | ///\code |
---|
795 | /// Lp lp; |
---|
796 | /// |
---|
797 | /// LemonWriter writer(filename_or_ostream); |
---|
798 | /// LpWriter lpwriter(writer, lp); |
---|
799 | /// |
---|
800 | /// writer.run(); |
---|
801 | ///\endcode |
---|
802 | /// |
---|
803 | /// Of course instead of \c LemonWriter you can give a \c |
---|
804 | /// GraphWriter to the LpWriter constructor. Also useful that you |
---|
805 | /// can mix lp problems and graphs in the same file. |
---|
806 | class LpWriter : public LemonWriter::SectionWriter { |
---|
807 | typedef LemonWriter::SectionWriter Parent; |
---|
808 | public: |
---|
809 | |
---|
810 | |
---|
811 | /// \brief Constructor. |
---|
812 | /// |
---|
813 | /// Constructor for LpWriter. It creates the LpWriter and attach |
---|
814 | /// it into the given LemonWriter. |
---|
815 | LpWriter(LemonWriter& _writer, const LpSolverBase& _lp, |
---|
816 | const std::string& _name = std::string()) |
---|
817 | : Parent(_writer), lp(_lp), name(_name) {} |
---|
818 | |
---|
819 | |
---|
820 | /// \brief Destructor. |
---|
821 | /// |
---|
822 | /// Destructor for LpWriter. |
---|
823 | virtual ~LpWriter() {} |
---|
824 | |
---|
825 | private: |
---|
826 | LpWriter(const LpWriter&); |
---|
827 | void operator=(const LpWriter&); |
---|
828 | |
---|
829 | protected: |
---|
830 | |
---|
831 | /// \brief Gives back true when the SectionWriter can process |
---|
832 | /// the section with the given header line. |
---|
833 | /// |
---|
834 | /// It gives back the header line of the \c \@lp section. |
---|
835 | virtual std::string header() { |
---|
836 | std::ostringstream ls; |
---|
837 | ls << "@lp " << name; |
---|
838 | return ls.str(); |
---|
839 | } |
---|
840 | |
---|
841 | private: |
---|
842 | |
---|
843 | void createCols() { |
---|
844 | int num = 0; |
---|
845 | |
---|
846 | for (LpSolverBase::ColIt it(lp); it != INVALID; ++it) { |
---|
847 | std::string name = lp.colName(it); |
---|
848 | if (name.empty()) { |
---|
849 | std::ostringstream ls; |
---|
850 | ls << "x" << num; |
---|
851 | ++num; |
---|
852 | while (lp.colByName(ls.str()) != INVALID) { |
---|
853 | ls.str(std::string()); |
---|
854 | ls << "x" << num; |
---|
855 | ++num; |
---|
856 | } |
---|
857 | const_cast<LpSolverBase&>(lp).colName(it, ls.str()); |
---|
858 | } |
---|
859 | } |
---|
860 | } |
---|
861 | |
---|
862 | void writeExpression(std::ostream& os, const LpSolverBase::Expr& e) { |
---|
863 | bool first = true; |
---|
864 | for (LpSolverBase::Expr::const_iterator jt = e.begin(); |
---|
865 | jt != e.end(); ++jt) { |
---|
866 | if (jt->second < 0.0) { |
---|
867 | os << "- "; |
---|
868 | if (jt->second != -1.0) { |
---|
869 | os << -jt->second << " * "; |
---|
870 | } |
---|
871 | } else if (jt->second > 0.0) { |
---|
872 | if (!first) { |
---|
873 | os << "+ "; |
---|
874 | } |
---|
875 | if (jt->second != 1.0) { |
---|
876 | os << jt->second << " * "; |
---|
877 | } |
---|
878 | } |
---|
879 | first = false; |
---|
880 | os << lp.colName(jt->first) << " "; |
---|
881 | } |
---|
882 | if (e.constComp() < 0.0) { |
---|
883 | os << "- " << -e.constComp() << " "; |
---|
884 | } else if (e.constComp() > 0.0) { |
---|
885 | if (!first) { |
---|
886 | os << "+ "; |
---|
887 | } |
---|
888 | os << e.constComp() << " "; |
---|
889 | } |
---|
890 | if (e.begin() == e.end() && e.constComp() == 0.0) { |
---|
891 | os << "0 "; |
---|
892 | } |
---|
893 | } |
---|
894 | |
---|
895 | protected: |
---|
896 | |
---|
897 | /// \brief Writer function of the section. |
---|
898 | /// |
---|
899 | /// It writes the content of the section. |
---|
900 | virtual void write(std::ostream& os) { |
---|
901 | createCols(); |
---|
902 | |
---|
903 | os << "constraints" << std::endl; |
---|
904 | |
---|
905 | for (LpSolverBase::RowIt it(lp); it != INVALID; ++it) { |
---|
906 | double lower, upper; |
---|
907 | lp.getRowBounds(it, lower, upper); |
---|
908 | if (lower == -LpSolverBase::INF && upper == LpSolverBase::INF) |
---|
909 | continue; |
---|
910 | os << " "; |
---|
911 | |
---|
912 | if (lower != upper) { |
---|
913 | if (lower != -LpSolverBase::INF) { |
---|
914 | os << lower << " <= "; |
---|
915 | } |
---|
916 | |
---|
917 | writeExpression(os, lp.row(it)); |
---|
918 | |
---|
919 | if (upper != LpSolverBase::INF) { |
---|
920 | os << "<= " << upper << " "; |
---|
921 | } |
---|
922 | } else { |
---|
923 | |
---|
924 | writeExpression(os, lp.row(it)); |
---|
925 | os << "== " << upper << " "; |
---|
926 | |
---|
927 | } |
---|
928 | |
---|
929 | os << std::endl; |
---|
930 | } |
---|
931 | |
---|
932 | os << "bounds" << std::endl; |
---|
933 | |
---|
934 | for (LpSolverBase::ColIt it(lp); it != INVALID; ++it) { |
---|
935 | double lower = lp.colLowerBound(it); |
---|
936 | double upper = lp.colUpperBound(it); |
---|
937 | if (lower == -LpSolverBase::INF && upper == LpSolverBase::INF) |
---|
938 | continue; |
---|
939 | os << " "; |
---|
940 | |
---|
941 | if (lower != upper) { |
---|
942 | if (lower != -LpSolverBase::INF) { |
---|
943 | os << lower << " <= "; |
---|
944 | } |
---|
945 | |
---|
946 | os << lp.colName(it) << " "; |
---|
947 | |
---|
948 | if (upper != LpSolverBase::INF) { |
---|
949 | os << "<= " << upper << " "; |
---|
950 | } |
---|
951 | } else { |
---|
952 | os << lp.colName(it) << " == " << upper << " "; |
---|
953 | } |
---|
954 | os << std::endl; |
---|
955 | } |
---|
956 | |
---|
957 | os << "objective" << std::endl; |
---|
958 | os << " "; |
---|
959 | if (lp.isMin()) { |
---|
960 | os << "min "; |
---|
961 | } else { |
---|
962 | os << "max "; |
---|
963 | } |
---|
964 | writeExpression(os, lp.obj()); |
---|
965 | os << std::endl; |
---|
966 | } |
---|
967 | |
---|
968 | |
---|
969 | private: |
---|
970 | |
---|
971 | const LpSolverBase& lp; |
---|
972 | std::string name; |
---|
973 | }; |
---|
974 | |
---|
975 | } |
---|
976 | |
---|
977 | #endif |
---|