[2316] | 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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