1 | /* -*- C++ -*- |
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2 | * src/lemon/lin_expr.h - Part of LEMON, a generic C++ optimization library |
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3 | * |
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4 | * Copyright (C) 2005 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
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5 | * (Egervary Combinatorial Optimization Research Group, EGRES). |
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6 | * |
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7 | * Permission to use, modify and distribute this software is granted |
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8 | * provided that this copyright notice appears in all copies. For |
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9 | * precise terms see the accompanying LICENSE file. |
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10 | * |
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11 | * This software is provided "AS IS" with no warranty of any kind, |
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12 | * express or implied, and with no claim as to its suitability for any |
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13 | * purpose. |
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14 | * |
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15 | */ |
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16 | |
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17 | #ifndef LEMON_LIN_EXPR_H |
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18 | #define LEMON_LIN_EXPR_H |
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19 | |
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20 | #include<vector> |
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21 | |
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22 | |
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23 | #include<map> |
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24 | |
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25 | ///\file |
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26 | ///\brief Classes to handle linear expressions |
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27 | namespace lemon { |
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28 | |
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29 | /// Class to handle sparse linear expressions |
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30 | template <class _V,class _C> |
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31 | class SparseLinExpr : public std::map<_V, _C> |
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32 | { |
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33 | public: |
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34 | typedef _V Var; |
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35 | typedef _C Coeff; |
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36 | |
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37 | protected: |
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38 | typedef typename std::map<_V, _C> Base; |
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39 | |
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40 | Coeff const_comp; |
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41 | public: |
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42 | SparseLinExpr() { } |
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43 | SparseLinExpr(const Var &v) : const_comp(v) { |
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44 | Base::insert(std::make_pair(v, 1)); |
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45 | } |
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46 | SparseLinExpr(const Coeff &v) : const_comp(v) {} |
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47 | |
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48 | void set(const Var &v,const Coeff &c) { |
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49 | return Base::insert(std::make_pair(v, c)); |
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50 | } |
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51 | // Coeff &operator[](const Var &v) { return data[v]; } |
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52 | // const Coeff &operator[](const Var &v) const { return data[v]; } |
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53 | |
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54 | Coeff &constComp() { return const_comp; } |
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55 | const Coeff &constComp() const { return const_comp; } |
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56 | |
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57 | ///Removes the components with zero coefficient. |
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58 | void simplify() { |
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59 | for (typename Base::iterator i=Base::begin(); i!=Base::end();) { |
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60 | typename Base::iterator j=i; |
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61 | ++j; |
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62 | if ((*i).second==0) Base::erase(i); |
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63 | j=i; |
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64 | } |
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65 | } |
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66 | |
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67 | }; |
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68 | |
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69 | } //namespace lemon |
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70 | |
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71 | #endif //LEMON_LIN_EXPR_H |
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