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) 2003-2006 |
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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 | |
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26 | namespace lemon { |
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27 | |
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28 | class LpReader : public LemonReader::SectionReader { |
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29 | typedef LemonReader::SectionReader Parent; |
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30 | public: |
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31 | |
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32 | |
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33 | /// \brief Constructor. |
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34 | /// |
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35 | /// Constructor for LpReader. It creates the LpReader and attach |
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36 | /// it into the given LemonReader. The lp reader will add |
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37 | /// variables, constraints and objective function to the |
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38 | /// given lp solver. |
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39 | LpReader(LemonReader& _reader, LpSolverBase& _lp, |
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40 | const std::string& _name = std::string()) |
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41 | : Parent(_reader), lp(_lp), name(_name) {} |
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42 | |
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43 | |
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44 | /// \brief Destructor. |
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45 | /// |
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46 | /// Destructor for NodeSetReader. |
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47 | virtual ~LpReader() {} |
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48 | |
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49 | private: |
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50 | LpReader(const LpReader&); |
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51 | void operator=(const LpReader&); |
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52 | |
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53 | protected: |
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54 | |
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55 | /// \brief Gives back true when the SectionReader can process |
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56 | /// the section with the given header line. |
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57 | /// |
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58 | /// It gives back true when the header line starts with \c \@lp, |
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59 | /// and the header line's name and the nodeset's name are the same. |
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60 | virtual bool header(const std::string& line) { |
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61 | std::istringstream ls(line); |
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62 | std::string command; |
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63 | std::string id; |
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64 | ls >> command >> id; |
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65 | return command == "@lp" && name == id; |
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66 | } |
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67 | |
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68 | private: |
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69 | |
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70 | enum Relation { |
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71 | LE, EQ, GE |
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72 | }; |
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73 | |
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74 | std::istream& readConstraint(std::istream& is, LpSolverBase::Constr& c) { |
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75 | char x; |
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76 | LpSolverBase::Expr e1, e2; |
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77 | Relation op1; |
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78 | is >> std::ws; |
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79 | readExpression(is, e1); |
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80 | is >> std::ws; |
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81 | readRelation(is, op1); |
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82 | is >> std::ws; |
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83 | readExpression(is, e2); |
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84 | if (!is.get(x)) { |
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85 | if (op1 == LE) { |
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86 | c = e1 <= e2; |
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87 | } else if (op1 == GE) { |
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88 | c = e1 >= e2; |
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89 | } else { |
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90 | c = e1 == e2; |
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91 | } |
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92 | } else { |
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93 | is.putback(x); |
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94 | LpSolverBase::Expr e3; |
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95 | Relation op2; |
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96 | readRelation(is, op2); |
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97 | is >> std::ws; |
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98 | readExpression(is, e3); |
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99 | if (!e1.empty() || !e3.empty()) { |
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100 | throw DataFormatError("Wrong range format"); |
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101 | } |
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102 | if (op2 != op1 || op1 == EQ) { |
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103 | throw DataFormatError("Wrong range format"); |
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104 | } |
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105 | if (op1 == LE) { |
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106 | c = e1.constComp() <= e2 <= e3.constComp(); |
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107 | } else { |
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108 | c = e1.constComp() >= e2 >= e3.constComp(); |
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109 | } |
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110 | } |
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111 | } |
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112 | |
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113 | std::istream& readExpression(std::istream& is, LpSolverBase::Expr& e) { |
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114 | LpSolverBase::Col c; |
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115 | double d; |
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116 | char x; |
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117 | readElement(is, c, d); |
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118 | if (c != INVALID) { |
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119 | e += d * c; |
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120 | } else { |
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121 | e += d; |
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122 | } |
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123 | is >> std::ws; |
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124 | while (is.get(x) && (x == '+' || x == '-')) { |
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125 | is >> std::ws; |
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126 | readElement(is, c, d); |
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127 | if (c != INVALID) { |
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128 | e += (x == '+' ? d : -d) * c; |
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129 | } else { |
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130 | e += (x == '+' ? d : -d); |
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131 | } |
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132 | is >> std::ws; |
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133 | } |
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134 | if (!is) { |
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135 | is.clear(); |
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136 | } else { |
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137 | is.putback(x); |
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138 | } |
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139 | return is; |
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140 | } |
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141 | |
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142 | std::istream& readElement(std::istream& is, |
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143 | LpSolverBase::Col& c, double& d) { |
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144 | d = 1.0; |
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145 | c = INVALID; |
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146 | char x, y; |
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147 | if (!is.get(x)) throw DataFormatError("Cannot find lp element"); |
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148 | if (x == '+' || x == '-') { |
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149 | is >> std::ws; |
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150 | d *= x == '-' ? -1 : 1; |
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151 | while (is.get(x) && (x == '+' || x == '-')) { |
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152 | d *= x == '-' ? -1 : 1; |
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153 | is >> std::ws; |
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154 | } |
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155 | if (!is) throw DataFormatError("Cannot find lp element"); |
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156 | } |
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157 | if (numFirstChar(x)) { |
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158 | is.putback(x); |
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159 | double e; |
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160 | readNum(is, e); |
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161 | d *= e; |
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162 | } else if (varFirstChar(x)) { |
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163 | is.putback(x); |
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164 | LpSolverBase::Col f; |
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165 | readCol(is, f); |
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166 | c = f; |
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167 | } else { |
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168 | throw DataFormatError("Invalid expression format"); |
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169 | } |
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170 | is >> std::ws; |
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171 | while (is.get(y) && (y == '*' || y == '/')) { |
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172 | is >> std::ws; |
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173 | if (!is.get(x)) throw DataFormatError("Cannot find lp element"); |
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174 | if (x == '+' || x == '-') { |
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175 | is >> std::ws; |
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176 | d *= x == '-' ? -1 : 1; |
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177 | while (is.get(x) && (x == '+' || x == '-')) { |
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178 | d *= x == '-' ? -1 : 1; |
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179 | is >> std::ws; |
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180 | } |
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181 | if (!is) throw DataFormatError("Cannot find lp element"); |
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182 | } |
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183 | if (numFirstChar(x)) { |
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184 | is.putback(x); |
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185 | double e; |
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186 | readNum(is, e); |
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187 | if (y == '*') { |
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188 | d *= e; |
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189 | } else { |
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190 | d /= e; |
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191 | } |
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192 | } else if (varFirstChar(x)) { |
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193 | is.putback(x); |
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194 | LpSolverBase::Col f; |
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195 | readCol(is, f); |
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196 | if (y == '*') { |
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197 | if (c == INVALID) { |
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198 | c = f; |
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199 | } else { |
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200 | throw DataFormatError("Quadratic element in expression"); |
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201 | } |
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202 | } else { |
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203 | throw DataFormatError("Division by variable"); |
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204 | } |
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205 | } else { |
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206 | throw DataFormatError("Invalid expression format"); |
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207 | } |
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208 | is >> std::ws; |
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209 | } |
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210 | if (!is) { |
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211 | is.clear(); |
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212 | } else { |
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213 | is.putback(y); |
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214 | } |
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215 | return is; |
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216 | } |
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217 | |
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218 | std::istream& readCol(std::istream& is, LpSolverBase::Col& c) { |
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219 | char x; |
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220 | std::string var; |
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221 | while (is.get(x) && varChar(x)) { |
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222 | var += x; |
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223 | } |
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224 | if (!is) { |
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225 | is.clear(); |
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226 | } else { |
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227 | is.putback(x); |
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228 | } |
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229 | ColMap::const_iterator it = cols.find(var); |
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230 | if (cols.find(var) != cols.end()) { |
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231 | c = it->second; |
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232 | } else { |
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233 | c = lp.addCol(); |
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234 | cols.insert(std::make_pair(var, c)); |
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235 | lp.colName(c, var); |
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236 | } |
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237 | return is; |
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238 | } |
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239 | |
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240 | std::istream& readNum(std::istream& is, double& d) { |
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241 | is >> d; |
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242 | if (!is) throw DataFormatError("Wrong number format"); |
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243 | return is; |
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244 | } |
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245 | |
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246 | std::istream& readRelation(std::istream& is, Relation& op) { |
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247 | char x, y; |
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248 | if (!is.get(x) || !(x == '<' || x == '=' || x == '>')) { |
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249 | throw DataFormatError("Wrong relation operator"); |
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250 | } |
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251 | if (!is.get(y) || y != '=') { |
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252 | throw DataFormatError("Wrong relation operator"); |
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253 | } |
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254 | switch (x) { |
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255 | case '<': op = LE; |
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256 | break; |
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257 | case '=': op = EQ; |
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258 | break; |
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259 | case '>': op = GE; |
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260 | break; |
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261 | } |
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262 | return is; |
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263 | } |
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264 | |
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265 | static bool relationFirstChar(char c) { |
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266 | return c == '<' || c == '=' || c == '>'; |
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267 | } |
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268 | |
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269 | static bool varFirstChar(char c) { |
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270 | return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z'); |
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271 | } |
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272 | |
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273 | static bool numFirstChar(char c) { |
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274 | return (c >= '0' && c <= '9') || c == '.'; |
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275 | } |
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276 | |
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277 | static bool varChar(char c) { |
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278 | return (c >= '0' && c <= '9') || |
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279 | (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z'); |
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280 | } |
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281 | |
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282 | |
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283 | void addConstraint(const LpSolverBase::Constr& constr) { |
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284 | if (constr.expr().size() != 1) { |
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285 | lp.addRow(constr); |
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286 | } else { |
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287 | Lp::Expr e = constr.expr(); |
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288 | LpSolverBase::Col col = e.begin()->first; |
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289 | double coeff = e.begin()->second; |
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290 | double lb = LpSolverBase::NaN; |
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291 | double ub = LpSolverBase::NaN; |
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292 | if (coeff > 0) { |
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293 | if (constr.upperBounded()) { |
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294 | lb = (constr.lowerBound() - e.constComp()) / coeff; |
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295 | } |
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296 | if (constr.lowerBounded()) { |
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297 | ub = (constr.upperBound() - e.constComp()) / coeff; |
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298 | } |
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299 | } else if (coeff < 0) { |
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300 | if (constr.upperBounded()) { |
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301 | lb = (constr.upperBound() - e.constComp()) / coeff; |
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302 | } |
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303 | if (constr.lowerBounded()) { |
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304 | ub = (constr.lowerBound() - e.constComp()) / coeff; |
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305 | } |
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306 | } else { |
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307 | lb = -LpSolverBase::INF; |
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308 | ub = LpSolverBase::INF; |
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309 | } |
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310 | lp.colLowerBound(col, lb); |
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311 | lp.colUpperBound(col, ub); |
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312 | } |
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313 | } |
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314 | |
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315 | protected: |
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316 | |
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317 | /// \brief Reader function of the section. |
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318 | /// |
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319 | /// It reads the content of the section. |
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320 | virtual void read(std::istream& is) { |
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321 | std::string line; |
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322 | std::map<std::string, LpSolverBase::Col> vars; |
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323 | while (getline(is, line)) { |
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324 | std::istringstream ls(line); |
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325 | std::string sense; |
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326 | ls >> sense; |
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327 | if (sense == "min" || sense == "max") { |
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328 | LpSolverBase::Expr expr; |
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329 | ls >> std::ws; |
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330 | readExpression(ls, expr); |
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331 | lp.setObj(expr); |
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332 | if (sense == "min") { |
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333 | lp.min(); |
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334 | } else { |
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335 | lp.max(); |
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336 | } |
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337 | } else { |
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338 | ls.str(line); |
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339 | LpSolverBase::Constr constr; |
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340 | ls >> std::ws; |
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341 | readConstraint(ls, constr); |
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342 | addConstraint(constr); |
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343 | } |
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344 | } |
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345 | } |
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346 | |
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347 | virtual void missing() { |
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348 | ErrorMessage msg; |
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349 | msg << "Lp section not found in file: @lp " << name; |
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350 | throw IoParameterError(msg.message()); |
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351 | } |
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352 | |
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353 | private: |
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354 | |
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355 | typedef std::map<std::string, LpSolverBase::Col> ColMap; |
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356 | |
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357 | LpSolverBase& lp; |
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358 | std::string name; |
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359 | ColMap cols; |
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360 | }; |
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361 | |
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362 | } |
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363 | |
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364 | #endif |
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