[1699] | 1 | /* -*- C++ -*- |
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| 2 | * |
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[1956] | 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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[1699] | 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_BELMANN_FORD_H |
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| 20 | #define LEMON_BELMANN_FORD_H |
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| 21 | |
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[1858] | 22 | /// \ingroup flowalgs |
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[1699] | 23 | /// \file |
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[1864] | 24 | /// \brief BellmanFord algorithm. |
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[1699] | 25 | /// |
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| 26 | |
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| 27 | #include <lemon/list_graph.h> |
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[2335] | 28 | #include <lemon/bits/path_dump.h> |
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[1993] | 29 | #include <lemon/bits/invalid.h> |
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[1699] | 30 | #include <lemon/error.h> |
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| 31 | #include <lemon/maps.h> |
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| 32 | |
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| 33 | #include <limits> |
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| 34 | |
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| 35 | namespace lemon { |
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| 36 | |
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[1864] | 37 | /// \brief Default OperationTraits for the BellmanFord algorithm class. |
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[1699] | 38 | /// |
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| 39 | /// It defines all computational operations and constants which are |
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[1864] | 40 | /// used in the bellman ford algorithm. The default implementation |
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[1699] | 41 | /// is based on the numeric_limits class. If the numeric type does not |
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| 42 | /// have infinity value then the maximum value is used as extremal |
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| 43 | /// infinity value. |
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| 44 | template < |
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| 45 | typename Value, |
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| 46 | bool has_infinity = std::numeric_limits<Value>::has_infinity> |
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[1864] | 47 | struct BellmanFordDefaultOperationTraits { |
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[1699] | 48 | /// \brief Gives back the zero value of the type. |
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| 49 | static Value zero() { |
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| 50 | return static_cast<Value>(0); |
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| 51 | } |
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| 52 | /// \brief Gives back the positive infinity value of the type. |
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| 53 | static Value infinity() { |
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| 54 | return std::numeric_limits<Value>::infinity(); |
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| 55 | } |
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| 56 | /// \brief Gives back the sum of the given two elements. |
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| 57 | static Value plus(const Value& left, const Value& right) { |
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| 58 | return left + right; |
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| 59 | } |
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| 60 | /// \brief Gives back true only if the first value less than the second. |
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| 61 | static bool less(const Value& left, const Value& right) { |
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| 62 | return left < right; |
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| 63 | } |
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| 64 | }; |
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| 65 | |
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| 66 | template <typename Value> |
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[1864] | 67 | struct BellmanFordDefaultOperationTraits<Value, false> { |
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[1699] | 68 | static Value zero() { |
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| 69 | return static_cast<Value>(0); |
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| 70 | } |
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| 71 | static Value infinity() { |
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| 72 | return std::numeric_limits<Value>::max(); |
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| 73 | } |
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| 74 | static Value plus(const Value& left, const Value& right) { |
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| 75 | if (left == infinity() || right == infinity()) return infinity(); |
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| 76 | return left + right; |
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| 77 | } |
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| 78 | static bool less(const Value& left, const Value& right) { |
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| 79 | return left < right; |
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| 80 | } |
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| 81 | }; |
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| 82 | |
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[1864] | 83 | /// \brief Default traits class of BellmanFord class. |
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[1699] | 84 | /// |
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[1864] | 85 | /// Default traits class of BellmanFord class. |
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[1699] | 86 | /// \param _Graph Graph type. |
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| 87 | /// \param _LegthMap Type of length map. |
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| 88 | template<class _Graph, class _LengthMap> |
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[1864] | 89 | struct BellmanFordDefaultTraits { |
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[1699] | 90 | /// The graph type the algorithm runs on. |
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| 91 | typedef _Graph Graph; |
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| 92 | |
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| 93 | /// \brief The type of the map that stores the edge lengths. |
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| 94 | /// |
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| 95 | /// The type of the map that stores the edge lengths. |
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[2260] | 96 | /// It must meet the \ref concepts::ReadMap "ReadMap" concept. |
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[1699] | 97 | typedef _LengthMap LengthMap; |
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| 98 | |
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| 99 | // The type of the length of the edges. |
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| 100 | typedef typename _LengthMap::Value Value; |
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| 101 | |
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[1864] | 102 | /// \brief Operation traits for bellman-ford algorithm. |
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[1699] | 103 | /// |
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| 104 | /// It defines the infinity type on the given Value type |
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| 105 | /// and the used operation. |
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[1864] | 106 | /// \see BellmanFordDefaultOperationTraits |
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| 107 | typedef BellmanFordDefaultOperationTraits<Value> OperationTraits; |
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[1699] | 108 | |
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| 109 | /// \brief The type of the map that stores the last edges of the |
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| 110 | /// shortest paths. |
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| 111 | /// |
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| 112 | /// The type of the map that stores the last |
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| 113 | /// edges of the shortest paths. |
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[2260] | 114 | /// It must meet the \ref concepts::WriteMap "WriteMap" concept. |
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[1699] | 115 | /// |
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| 116 | typedef typename Graph::template NodeMap<typename _Graph::Edge> PredMap; |
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| 117 | |
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| 118 | /// \brief Instantiates a PredMap. |
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| 119 | /// |
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| 120 | /// This function instantiates a \ref PredMap. |
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[1858] | 121 | /// \param graph is the graph, to which we would like to define the PredMap. |
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[1699] | 122 | static PredMap *createPredMap(const _Graph& graph) { |
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| 123 | return new PredMap(graph); |
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| 124 | } |
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| 125 | |
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| 126 | /// \brief The type of the map that stores the dists of the nodes. |
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| 127 | /// |
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| 128 | /// The type of the map that stores the dists of the nodes. |
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[2260] | 129 | /// It must meet the \ref concepts::WriteMap "WriteMap" concept. |
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[1699] | 130 | /// |
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| 131 | typedef typename Graph::template NodeMap<typename _LengthMap::Value> |
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| 132 | DistMap; |
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| 133 | |
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| 134 | /// \brief Instantiates a DistMap. |
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| 135 | /// |
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| 136 | /// This function instantiates a \ref DistMap. |
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[1858] | 137 | /// \param graph is the graph, to which we would like to define the |
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[1699] | 138 | /// \ref DistMap |
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| 139 | static DistMap *createDistMap(const _Graph& graph) { |
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| 140 | return new DistMap(graph); |
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| 141 | } |
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| 142 | |
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| 143 | }; |
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| 144 | |
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[1864] | 145 | /// \brief %BellmanFord algorithm class. |
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[1699] | 146 | /// |
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| 147 | /// \ingroup flowalgs |
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[1864] | 148 | /// This class provides an efficient implementation of \c Bellman-Ford |
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[1699] | 149 | /// algorithm. The edge lengths are passed to the algorithm using a |
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[2260] | 150 | /// \ref concepts::ReadMap "ReadMap", so it is easy to change it to any |
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[1699] | 151 | /// kind of length. |
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| 152 | /// |
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[1864] | 153 | /// The Bellman-Ford algorithm solves the shortest path from one node |
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[1723] | 154 | /// problem when the edges can have negative length but the graph should |
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[1754] | 155 | /// not contain cycles with negative sum of length. If we can assume |
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[1723] | 156 | /// that all edge is non-negative in the graph then the dijkstra algorithm |
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| 157 | /// should be used rather. |
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| 158 | /// |
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[2042] | 159 | /// The maximal time complexity of the algorithm is \f$ O(ne) \f$. |
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[1723] | 160 | /// |
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[1699] | 161 | /// The type of the length is determined by the |
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[2260] | 162 | /// \ref concepts::ReadMap::Value "Value" of the length map. |
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[1699] | 163 | /// |
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| 164 | /// \param _Graph The graph type the algorithm runs on. The default value |
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| 165 | /// is \ref ListGraph. The value of _Graph is not used directly by |
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[1864] | 166 | /// BellmanFord, it is only passed to \ref BellmanFordDefaultTraits. |
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[1699] | 167 | /// \param _LengthMap This read-only EdgeMap determines the lengths of the |
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[2260] | 168 | /// edges. The default map type is \ref concepts::Graph::EdgeMap |
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[1699] | 169 | /// "Graph::EdgeMap<int>". The value of _LengthMap is not used directly |
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[1864] | 170 | /// by BellmanFord, it is only passed to \ref BellmanFordDefaultTraits. |
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[1699] | 171 | /// \param _Traits Traits class to set various data types used by the |
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[1864] | 172 | /// algorithm. The default traits class is \ref BellmanFordDefaultTraits |
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| 173 | /// "BellmanFordDefaultTraits<_Graph,_LengthMap>". See \ref |
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| 174 | /// BellmanFordDefaultTraits for the documentation of a BellmanFord traits |
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[1699] | 175 | /// class. |
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| 176 | /// |
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| 177 | /// \author Balazs Dezso |
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| 178 | |
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[1710] | 179 | #ifdef DOXYGEN |
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| 180 | template <typename _Graph, typename _LengthMap, typename _Traits> |
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| 181 | #else |
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[1699] | 182 | template <typename _Graph=ListGraph, |
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| 183 | typename _LengthMap=typename _Graph::template EdgeMap<int>, |
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[1864] | 184 | typename _Traits=BellmanFordDefaultTraits<_Graph,_LengthMap> > |
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[1710] | 185 | #endif |
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[1864] | 186 | class BellmanFord { |
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[1699] | 187 | public: |
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| 188 | |
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| 189 | /// \brief \ref Exception for uninitialized parameters. |
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| 190 | /// |
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| 191 | /// This error represents problems in the initialization |
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| 192 | /// of the parameters of the algorithms. |
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| 193 | |
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| 194 | class UninitializedParameter : public lemon::UninitializedParameter { |
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| 195 | public: |
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[2151] | 196 | virtual const char* what() const throw() { |
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[1864] | 197 | return "lemon::BellmanFord::UninitializedParameter"; |
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[1699] | 198 | } |
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| 199 | }; |
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| 200 | |
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| 201 | typedef _Traits Traits; |
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| 202 | ///The type of the underlying graph. |
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| 203 | typedef typename _Traits::Graph Graph; |
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| 204 | |
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| 205 | typedef typename Graph::Node Node; |
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| 206 | typedef typename Graph::NodeIt NodeIt; |
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| 207 | typedef typename Graph::Edge Edge; |
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[1781] | 208 | typedef typename Graph::OutEdgeIt OutEdgeIt; |
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[1699] | 209 | |
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| 210 | /// \brief The type of the length of the edges. |
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| 211 | typedef typename _Traits::LengthMap::Value Value; |
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| 212 | /// \brief The type of the map that stores the edge lengths. |
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| 213 | typedef typename _Traits::LengthMap LengthMap; |
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| 214 | /// \brief The type of the map that stores the last |
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| 215 | /// edges of the shortest paths. |
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| 216 | typedef typename _Traits::PredMap PredMap; |
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| 217 | /// \brief The type of the map that stores the dists of the nodes. |
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| 218 | typedef typename _Traits::DistMap DistMap; |
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| 219 | /// \brief The operation traits. |
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| 220 | typedef typename _Traits::OperationTraits OperationTraits; |
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| 221 | private: |
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| 222 | /// Pointer to the underlying graph. |
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| 223 | const Graph *graph; |
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| 224 | /// Pointer to the length map |
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| 225 | const LengthMap *length; |
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| 226 | ///Pointer to the map of predecessors edges. |
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| 227 | PredMap *_pred; |
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| 228 | ///Indicates if \ref _pred is locally allocated (\c true) or not. |
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| 229 | bool local_pred; |
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| 230 | ///Pointer to the map of distances. |
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| 231 | DistMap *_dist; |
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| 232 | ///Indicates if \ref _dist is locally allocated (\c true) or not. |
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| 233 | bool local_dist; |
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| 234 | |
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[1781] | 235 | typedef typename Graph::template NodeMap<bool> MaskMap; |
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| 236 | MaskMap *_mask; |
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| 237 | |
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| 238 | std::vector<Node> _process; |
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| 239 | |
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[1699] | 240 | /// Creates the maps if necessary. |
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| 241 | void create_maps() { |
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| 242 | if(!_pred) { |
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| 243 | local_pred = true; |
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| 244 | _pred = Traits::createPredMap(*graph); |
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| 245 | } |
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| 246 | if(!_dist) { |
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| 247 | local_dist = true; |
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| 248 | _dist = Traits::createDistMap(*graph); |
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| 249 | } |
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[1781] | 250 | _mask = new MaskMap(*graph, false); |
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[1699] | 251 | } |
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| 252 | |
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| 253 | public : |
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| 254 | |
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[1864] | 255 | typedef BellmanFord Create; |
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[1710] | 256 | |
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[1699] | 257 | /// \name Named template parameters |
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| 258 | |
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| 259 | ///@{ |
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| 260 | |
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| 261 | template <class T> |
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| 262 | struct DefPredMapTraits : public Traits { |
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| 263 | typedef T PredMap; |
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[1710] | 264 | static PredMap *createPredMap(const Graph&) { |
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[1699] | 265 | throw UninitializedParameter(); |
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| 266 | } |
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| 267 | }; |
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| 268 | |
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| 269 | /// \brief \ref named-templ-param "Named parameter" for setting PredMap |
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| 270 | /// type |
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| 271 | /// \ref named-templ-param "Named parameter" for setting PredMap type |
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| 272 | /// |
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| 273 | template <class T> |
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[1858] | 274 | struct DefPredMap |
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[1864] | 275 | : public BellmanFord< Graph, LengthMap, DefPredMapTraits<T> > { |
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| 276 | typedef BellmanFord< Graph, LengthMap, DefPredMapTraits<T> > Create; |
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[1710] | 277 | }; |
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[1699] | 278 | |
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| 279 | template <class T> |
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| 280 | struct DefDistMapTraits : public Traits { |
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| 281 | typedef T DistMap; |
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[2010] | 282 | static DistMap *createDistMap(const Graph&) { |
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[1699] | 283 | throw UninitializedParameter(); |
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| 284 | } |
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| 285 | }; |
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| 286 | |
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| 287 | /// \brief \ref named-templ-param "Named parameter" for setting DistMap |
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| 288 | /// type |
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| 289 | /// |
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| 290 | /// \ref named-templ-param "Named parameter" for setting DistMap type |
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| 291 | /// |
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| 292 | template <class T> |
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[1710] | 293 | struct DefDistMap |
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[1864] | 294 | : public BellmanFord< Graph, LengthMap, DefDistMapTraits<T> > { |
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| 295 | typedef BellmanFord< Graph, LengthMap, DefDistMapTraits<T> > Create; |
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[1710] | 296 | }; |
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[1699] | 297 | |
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| 298 | template <class T> |
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| 299 | struct DefOperationTraitsTraits : public Traits { |
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| 300 | typedef T OperationTraits; |
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| 301 | }; |
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| 302 | |
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| 303 | /// \brief \ref named-templ-param "Named parameter" for setting |
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| 304 | /// OperationTraits type |
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| 305 | /// |
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[1710] | 306 | /// \ref named-templ-param "Named parameter" for setting OperationTraits |
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| 307 | /// type |
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[1699] | 308 | template <class T> |
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[1710] | 309 | struct DefOperationTraits |
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[1864] | 310 | : public BellmanFord< Graph, LengthMap, DefOperationTraitsTraits<T> > { |
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| 311 | typedef BellmanFord< Graph, LengthMap, DefOperationTraitsTraits<T> > |
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[1710] | 312 | Create; |
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[1699] | 313 | }; |
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| 314 | |
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| 315 | ///@} |
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| 316 | |
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[1710] | 317 | protected: |
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| 318 | |
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[1864] | 319 | BellmanFord() {} |
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[1710] | 320 | |
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[1699] | 321 | public: |
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| 322 | |
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| 323 | /// \brief Constructor. |
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| 324 | /// |
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| 325 | /// \param _graph the graph the algorithm will run on. |
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| 326 | /// \param _length the length map used by the algorithm. |
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[1864] | 327 | BellmanFord(const Graph& _graph, const LengthMap& _length) : |
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[1699] | 328 | graph(&_graph), length(&_length), |
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| 329 | _pred(0), local_pred(false), |
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[2074] | 330 | _dist(0), local_dist(false), _mask(0) {} |
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[1699] | 331 | |
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| 332 | ///Destructor. |
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[1864] | 333 | ~BellmanFord() { |
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[1699] | 334 | if(local_pred) delete _pred; |
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| 335 | if(local_dist) delete _dist; |
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[2074] | 336 | if(_mask) delete _mask; |
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[1699] | 337 | } |
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| 338 | |
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| 339 | /// \brief Sets the length map. |
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| 340 | /// |
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| 341 | /// Sets the length map. |
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| 342 | /// \return \c (*this) |
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[1864] | 343 | BellmanFord &lengthMap(const LengthMap &m) { |
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[1699] | 344 | length = &m; |
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| 345 | return *this; |
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| 346 | } |
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| 347 | |
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| 348 | /// \brief Sets the map storing the predecessor edges. |
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| 349 | /// |
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| 350 | /// Sets the map storing the predecessor edges. |
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| 351 | /// If you don't use this function before calling \ref run(), |
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| 352 | /// it will allocate one. The destuctor deallocates this |
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| 353 | /// automatically allocated map, of course. |
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| 354 | /// \return \c (*this) |
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[1864] | 355 | BellmanFord &predMap(PredMap &m) { |
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[1699] | 356 | if(local_pred) { |
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| 357 | delete _pred; |
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| 358 | local_pred=false; |
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| 359 | } |
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| 360 | _pred = &m; |
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| 361 | return *this; |
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| 362 | } |
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| 363 | |
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| 364 | /// \brief Sets the map storing the distances calculated by the algorithm. |
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| 365 | /// |
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| 366 | /// Sets the map storing the distances calculated by the algorithm. |
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| 367 | /// If you don't use this function before calling \ref run(), |
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| 368 | /// it will allocate one. The destuctor deallocates this |
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| 369 | /// automatically allocated map, of course. |
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| 370 | /// \return \c (*this) |
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[1864] | 371 | BellmanFord &distMap(DistMap &m) { |
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[1699] | 372 | if(local_dist) { |
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| 373 | delete _dist; |
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| 374 | local_dist=false; |
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| 375 | } |
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| 376 | _dist = &m; |
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| 377 | return *this; |
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| 378 | } |
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| 379 | |
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| 380 | /// \name Execution control |
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| 381 | /// The simplest way to execute the algorithm is to use |
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| 382 | /// one of the member functions called \c run(...). |
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| 383 | /// \n |
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| 384 | /// If you need more control on the execution, |
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| 385 | /// first you must call \ref init(), then you can add several source nodes |
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| 386 | /// with \ref addSource(). |
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| 387 | /// Finally \ref start() will perform the actual path |
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| 388 | /// computation. |
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| 389 | |
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| 390 | ///@{ |
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| 391 | |
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| 392 | /// \brief Initializes the internal data structures. |
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| 393 | /// |
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| 394 | /// Initializes the internal data structures. |
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[1710] | 395 | void init(const Value value = OperationTraits::infinity()) { |
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[1699] | 396 | create_maps(); |
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| 397 | for (NodeIt it(*graph); it != INVALID; ++it) { |
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| 398 | _pred->set(it, INVALID); |
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[1710] | 399 | _dist->set(it, value); |
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[1699] | 400 | } |
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[1781] | 401 | _process.clear(); |
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| 402 | if (OperationTraits::less(value, OperationTraits::infinity())) { |
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| 403 | for (NodeIt it(*graph); it != INVALID; ++it) { |
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| 404 | _process.push_back(it); |
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[1783] | 405 | _mask->set(it, true); |
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[1781] | 406 | } |
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| 407 | } |
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[1699] | 408 | } |
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| 409 | |
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| 410 | /// \brief Adds a new source node. |
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| 411 | /// |
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| 412 | /// The optional second parameter is the initial distance of the node. |
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| 413 | /// It just sets the distance of the node to the given value. |
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| 414 | void addSource(Node source, Value dst = OperationTraits::zero()) { |
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| 415 | _dist->set(source, dst); |
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[1781] | 416 | if (!(*_mask)[source]) { |
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| 417 | _process.push_back(source); |
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| 418 | _mask->set(source, true); |
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| 419 | } |
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| 420 | } |
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| 421 | |
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[1864] | 422 | /// \brief Executes one round from the bellman ford algorithm. |
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[1781] | 423 | /// |
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[2059] | 424 | /// If the algoritm calculated the distances in the previous round |
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| 425 | /// exactly for all at most \f$ k \f$ length path lengths then it will |
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| 426 | /// calculate the distances exactly for all at most \f$ k + 1 \f$ |
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| 427 | /// length path lengths. With \f$ k \f$ iteration this function |
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| 428 | /// calculates the at most \f$ k \f$ length path lengths. |
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| 429 | /// |
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| 430 | /// \warning The paths with limited edge number cannot be retrieved |
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[2335] | 431 | /// easily with \ref path() or \ref predEdge() functions. If you |
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[2059] | 432 | /// need the shortest path and not just the distance you should store |
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| 433 | /// after each iteration the \ref predEdgeMap() map and manually build |
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| 434 | /// the path. |
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| 435 | /// |
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| 436 | /// \return %True when the algorithm have not found more shorter |
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| 437 | /// paths. |
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[1781] | 438 | bool processNextRound() { |
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| 439 | for (int i = 0; i < (int)_process.size(); ++i) { |
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| 440 | _mask->set(_process[i], false); |
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| 441 | } |
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| 442 | std::vector<Node> nextProcess; |
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| 443 | std::vector<Value> values(_process.size()); |
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| 444 | for (int i = 0; i < (int)_process.size(); ++i) { |
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[1857] | 445 | values[i] = (*_dist)[_process[i]]; |
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[1781] | 446 | } |
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| 447 | for (int i = 0; i < (int)_process.size(); ++i) { |
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| 448 | for (OutEdgeIt it(*graph, _process[i]); it != INVALID; ++it) { |
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| 449 | Node target = graph->target(it); |
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| 450 | Value relaxed = OperationTraits::plus(values[i], (*length)[it]); |
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| 451 | if (OperationTraits::less(relaxed, (*_dist)[target])) { |
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| 452 | _pred->set(target, it); |
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| 453 | _dist->set(target, relaxed); |
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| 454 | if (!(*_mask)[target]) { |
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| 455 | _mask->set(target, true); |
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| 456 | nextProcess.push_back(target); |
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| 457 | } |
---|
| 458 | } |
---|
| 459 | } |
---|
| 460 | } |
---|
| 461 | _process.swap(nextProcess); |
---|
| 462 | return _process.empty(); |
---|
| 463 | } |
---|
| 464 | |
---|
[1864] | 465 | /// \brief Executes one weak round from the bellman ford algorithm. |
---|
[1781] | 466 | /// |
---|
| 467 | /// If the algorithm calculated the distances in the |
---|
[1816] | 468 | /// previous round at least for all at most k length paths then it will |
---|
| 469 | /// calculate the distances at least for all at most k + 1 length paths. |
---|
| 470 | /// This function does not make it possible to calculate strictly the |
---|
| 471 | /// at most k length minimal paths, this is why it is |
---|
| 472 | /// called just weak round. |
---|
[1858] | 473 | /// \return %True when the algorithm have not found more shorter paths. |
---|
[1781] | 474 | bool processNextWeakRound() { |
---|
| 475 | for (int i = 0; i < (int)_process.size(); ++i) { |
---|
| 476 | _mask->set(_process[i], false); |
---|
| 477 | } |
---|
| 478 | std::vector<Node> nextProcess; |
---|
| 479 | for (int i = 0; i < (int)_process.size(); ++i) { |
---|
| 480 | for (OutEdgeIt it(*graph, _process[i]); it != INVALID; ++it) { |
---|
| 481 | Node target = graph->target(it); |
---|
| 482 | Value relaxed = |
---|
| 483 | OperationTraits::plus((*_dist)[_process[i]], (*length)[it]); |
---|
| 484 | if (OperationTraits::less(relaxed, (*_dist)[target])) { |
---|
| 485 | _pred->set(target, it); |
---|
| 486 | _dist->set(target, relaxed); |
---|
| 487 | if (!(*_mask)[target]) { |
---|
| 488 | _mask->set(target, true); |
---|
| 489 | nextProcess.push_back(target); |
---|
| 490 | } |
---|
| 491 | } |
---|
| 492 | } |
---|
| 493 | } |
---|
| 494 | _process.swap(nextProcess); |
---|
| 495 | return _process.empty(); |
---|
[1699] | 496 | } |
---|
| 497 | |
---|
| 498 | /// \brief Executes the algorithm. |
---|
| 499 | /// |
---|
| 500 | /// \pre init() must be called and at least one node should be added |
---|
| 501 | /// with addSource() before using this function. |
---|
| 502 | /// |
---|
[1864] | 503 | /// This method runs the %BellmanFord algorithm from the root node(s) |
---|
[1699] | 504 | /// in order to compute the shortest path to each node. The algorithm |
---|
| 505 | /// computes |
---|
| 506 | /// - The shortest path tree. |
---|
| 507 | /// - The distance of each node from the root(s). |
---|
| 508 | void start() { |
---|
[1723] | 509 | int num = countNodes(*graph) - 1; |
---|
| 510 | for (int i = 0; i < num; ++i) { |
---|
[1781] | 511 | if (processNextWeakRound()) break; |
---|
[1699] | 512 | } |
---|
| 513 | } |
---|
[1723] | 514 | |
---|
[1754] | 515 | /// \brief Executes the algorithm and checks the negative cycles. |
---|
[1723] | 516 | /// |
---|
| 517 | /// \pre init() must be called and at least one node should be added |
---|
| 518 | /// with addSource() before using this function. If there is |
---|
[1754] | 519 | /// a negative cycles in the graph it gives back false. |
---|
[1723] | 520 | /// |
---|
[1864] | 521 | /// This method runs the %BellmanFord algorithm from the root node(s) |
---|
[1723] | 522 | /// in order to compute the shortest path to each node. The algorithm |
---|
| 523 | /// computes |
---|
| 524 | /// - The shortest path tree. |
---|
| 525 | /// - The distance of each node from the root(s). |
---|
| 526 | bool checkedStart() { |
---|
| 527 | int num = countNodes(*graph); |
---|
| 528 | for (int i = 0; i < num; ++i) { |
---|
[1781] | 529 | if (processNextWeakRound()) return true; |
---|
[1723] | 530 | } |
---|
| 531 | return false; |
---|
| 532 | } |
---|
[1781] | 533 | |
---|
| 534 | /// \brief Executes the algorithm with path length limit. |
---|
| 535 | /// |
---|
| 536 | /// \pre init() must be called and at least one node should be added |
---|
| 537 | /// with addSource() before using this function. |
---|
| 538 | /// |
---|
[2059] | 539 | /// This method runs the %BellmanFord algorithm from the root |
---|
| 540 | /// node(s) in order to compute the shortest path lengths with at |
---|
| 541 | /// most \c num edge. |
---|
| 542 | /// |
---|
| 543 | /// \warning The paths with limited edge number cannot be retrieved |
---|
[2335] | 544 | /// easily with \ref path() or \ref predEdge() functions. If you |
---|
[2059] | 545 | /// need the shortest path and not just the distance you should store |
---|
| 546 | /// after each iteration the \ref predEdgeMap() map and manually build |
---|
| 547 | /// the path. |
---|
| 548 | /// |
---|
| 549 | /// The algorithm computes |
---|
| 550 | /// - The predecessor edge from each node. |
---|
[1781] | 551 | /// - The limited distance of each node from the root(s). |
---|
[2059] | 552 | void limitedStart(int num) { |
---|
| 553 | for (int i = 0; i < num; ++i) { |
---|
[1781] | 554 | if (processNextRound()) break; |
---|
| 555 | } |
---|
| 556 | } |
---|
[1699] | 557 | |
---|
[1864] | 558 | /// \brief Runs %BellmanFord algorithm from node \c s. |
---|
[1699] | 559 | /// |
---|
[1864] | 560 | /// This method runs the %BellmanFord algorithm from a root node \c s |
---|
[1699] | 561 | /// in order to compute the shortest path to each node. The algorithm |
---|
| 562 | /// computes |
---|
| 563 | /// - The shortest path tree. |
---|
| 564 | /// - The distance of each node from the root. |
---|
| 565 | /// |
---|
| 566 | /// \note d.run(s) is just a shortcut of the following code. |
---|
[1946] | 567 | ///\code |
---|
[1699] | 568 | /// d.init(); |
---|
| 569 | /// d.addSource(s); |
---|
| 570 | /// d.start(); |
---|
[1946] | 571 | ///\endcode |
---|
[1699] | 572 | void run(Node s) { |
---|
| 573 | init(); |
---|
| 574 | addSource(s); |
---|
| 575 | start(); |
---|
| 576 | } |
---|
| 577 | |
---|
[1864] | 578 | /// \brief Runs %BellmanFord algorithm with limited path length |
---|
[1857] | 579 | /// from node \c s. |
---|
| 580 | /// |
---|
[1864] | 581 | /// This method runs the %BellmanFord algorithm from a root node \c s |
---|
[1857] | 582 | /// in order to compute the shortest path with at most \c len edges |
---|
| 583 | /// to each node. The algorithm computes |
---|
| 584 | /// - The shortest path tree. |
---|
| 585 | /// - The distance of each node from the root. |
---|
| 586 | /// |
---|
| 587 | /// \note d.run(s, len) is just a shortcut of the following code. |
---|
[1946] | 588 | ///\code |
---|
[1857] | 589 | /// d.init(); |
---|
| 590 | /// d.addSource(s); |
---|
| 591 | /// d.limitedStart(len); |
---|
[1946] | 592 | ///\endcode |
---|
[1857] | 593 | void run(Node s, int len) { |
---|
| 594 | init(); |
---|
| 595 | addSource(s); |
---|
| 596 | limitedStart(len); |
---|
| 597 | } |
---|
| 598 | |
---|
[1699] | 599 | ///@} |
---|
| 600 | |
---|
| 601 | /// \name Query Functions |
---|
[1864] | 602 | /// The result of the %BellmanFord algorithm can be obtained using these |
---|
[1699] | 603 | /// functions.\n |
---|
| 604 | /// Before the use of these functions, |
---|
| 605 | /// either run() or start() must be called. |
---|
| 606 | |
---|
| 607 | ///@{ |
---|
| 608 | |
---|
[2070] | 609 | /// \brief Lemon iterator for get a active nodes. |
---|
| 610 | /// |
---|
| 611 | /// Lemon iterator for get a active nodes. This class provides a |
---|
| 612 | /// common style lemon iterator which gives back a subset of the |
---|
| 613 | /// nodes. The iterated nodes are active in the algorithm after |
---|
| 614 | /// the last phase so these should be checked in the next phase to |
---|
| 615 | /// find augmenting edges from these. |
---|
| 616 | class ActiveIt { |
---|
| 617 | public: |
---|
| 618 | |
---|
| 619 | /// \brief Constructor. |
---|
| 620 | /// |
---|
| 621 | /// Constructor for get the nodeset of the variable. |
---|
| 622 | ActiveIt(const BellmanFord& algorithm) : _algorithm(&algorithm) |
---|
| 623 | { |
---|
| 624 | _index = _algorithm->_process.size() - 1; |
---|
| 625 | } |
---|
| 626 | |
---|
| 627 | /// \brief Invalid constructor. |
---|
| 628 | /// |
---|
| 629 | /// Invalid constructor. |
---|
| 630 | ActiveIt(Invalid) : _algorithm(0), _index(-1) {} |
---|
| 631 | |
---|
| 632 | /// \brief Conversion to node. |
---|
| 633 | /// |
---|
| 634 | /// Conversion to node. |
---|
| 635 | operator Node() const { |
---|
| 636 | return _index >= 0 ? _algorithm->_process[_index] : INVALID; |
---|
| 637 | } |
---|
| 638 | |
---|
| 639 | /// \brief Increment operator. |
---|
| 640 | /// |
---|
| 641 | /// Increment operator. |
---|
| 642 | ActiveIt& operator++() { |
---|
| 643 | --_index; |
---|
| 644 | return *this; |
---|
| 645 | } |
---|
| 646 | |
---|
| 647 | bool operator==(const ActiveIt& it) const { |
---|
| 648 | return (Node)(*this) == (Node)it; |
---|
| 649 | } |
---|
| 650 | bool operator!=(const ActiveIt& it) const { |
---|
| 651 | return (Node)(*this) != (Node)it; |
---|
| 652 | } |
---|
| 653 | bool operator<(const ActiveIt& it) const { |
---|
| 654 | return (Node)(*this) < (Node)it; |
---|
| 655 | } |
---|
| 656 | |
---|
| 657 | private: |
---|
| 658 | const BellmanFord* _algorithm; |
---|
| 659 | int _index; |
---|
| 660 | }; |
---|
| 661 | |
---|
[2335] | 662 | typedef PredMapPath<Graph, PredMap> Path; |
---|
| 663 | |
---|
| 664 | /// \brief Gives back the shortest path. |
---|
[1699] | 665 | /// |
---|
[2335] | 666 | /// Gives back the shortest path. |
---|
| 667 | /// \pre The \c t should be reachable from the source. |
---|
| 668 | Path path(Node t) |
---|
| 669 | { |
---|
| 670 | return Path(*graph, *_pred, t); |
---|
[1699] | 671 | } |
---|
[2070] | 672 | |
---|
[2335] | 673 | |
---|
| 674 | // TODO : implement negative cycle |
---|
| 675 | // /// \brief Gives back a negative cycle. |
---|
| 676 | // /// |
---|
| 677 | // /// This function gives back a negative cycle. |
---|
| 678 | // /// If the algorithm have not found yet negative cycle it will give back |
---|
| 679 | // /// an empty path. |
---|
| 680 | // Path negativeCycle() { |
---|
| 681 | // typename Graph::template NodeMap<int> state(*graph, 0); |
---|
| 682 | // for (ActiveIt it(*this); it != INVALID; ++it) { |
---|
| 683 | // if (state[it] == 0) { |
---|
| 684 | // for (Node t = it; predEdge(t) != INVALID; t = predNode(t)) { |
---|
| 685 | // if (state[t] == 0) { |
---|
| 686 | // state[t] = 1; |
---|
| 687 | // } else if (state[t] == 2) { |
---|
| 688 | // break; |
---|
| 689 | // } else { |
---|
| 690 | // p.clear(); |
---|
| 691 | // typename Path::Builder b(p); |
---|
| 692 | // b.setStartNode(t); |
---|
| 693 | // b.pushFront(predEdge(t)); |
---|
| 694 | // for(Node s = predNode(t); s != t; s = predNode(s)) { |
---|
| 695 | // b.pushFront(predEdge(s)); |
---|
| 696 | // } |
---|
| 697 | // b.commit(); |
---|
| 698 | // return true; |
---|
| 699 | // } |
---|
| 700 | // } |
---|
| 701 | // for (Node t = it; predEdge(t) != INVALID; t = predNode(t)) { |
---|
| 702 | // if (state[t] == 1) { |
---|
| 703 | // state[t] = 2; |
---|
| 704 | // } else { |
---|
| 705 | // break; |
---|
| 706 | // } |
---|
| 707 | // } |
---|
| 708 | // } |
---|
| 709 | // } |
---|
| 710 | // return false; |
---|
| 711 | // } |
---|
[1699] | 712 | |
---|
| 713 | /// \brief The distance of a node from the root. |
---|
| 714 | /// |
---|
| 715 | /// Returns the distance of a node from the root. |
---|
| 716 | /// \pre \ref run() must be called before using this function. |
---|
| 717 | /// \warning If node \c v in unreachable from the root the return value |
---|
| 718 | /// of this funcion is undefined. |
---|
| 719 | Value dist(Node v) const { return (*_dist)[v]; } |
---|
| 720 | |
---|
| 721 | /// \brief Returns the 'previous edge' of the shortest path tree. |
---|
| 722 | /// |
---|
| 723 | /// For a node \c v it returns the 'previous edge' of the shortest path |
---|
| 724 | /// tree, i.e. it returns the last edge of a shortest path from the root |
---|
| 725 | /// to \c v. It is \ref INVALID if \c v is unreachable from the root or |
---|
| 726 | /// if \c v=s. The shortest path tree used here is equal to the shortest |
---|
| 727 | /// path tree used in \ref predNode(). |
---|
| 728 | /// \pre \ref run() must be called before using |
---|
| 729 | /// this function. |
---|
[1763] | 730 | Edge predEdge(Node v) const { return (*_pred)[v]; } |
---|
[1699] | 731 | |
---|
| 732 | /// \brief Returns the 'previous node' of the shortest path tree. |
---|
| 733 | /// |
---|
| 734 | /// For a node \c v it returns the 'previous node' of the shortest path |
---|
| 735 | /// tree, i.e. it returns the last but one node from a shortest path from |
---|
| 736 | /// the root to \c /v. It is INVALID if \c v is unreachable from the root |
---|
| 737 | /// or if \c v=s. The shortest path tree used here is equal to the |
---|
[1763] | 738 | /// shortest path tree used in \ref predEdge(). \pre \ref run() must be |
---|
[1699] | 739 | /// called before using this function. |
---|
| 740 | Node predNode(Node v) const { |
---|
| 741 | return (*_pred)[v] == INVALID ? INVALID : graph->source((*_pred)[v]); |
---|
| 742 | } |
---|
| 743 | |
---|
| 744 | /// \brief Returns a reference to the NodeMap of distances. |
---|
| 745 | /// |
---|
| 746 | /// Returns a reference to the NodeMap of distances. \pre \ref run() must |
---|
| 747 | /// be called before using this function. |
---|
| 748 | const DistMap &distMap() const { return *_dist;} |
---|
| 749 | |
---|
| 750 | /// \brief Returns a reference to the shortest path tree map. |
---|
| 751 | /// |
---|
| 752 | /// Returns a reference to the NodeMap of the edges of the |
---|
| 753 | /// shortest path tree. |
---|
| 754 | /// \pre \ref run() must be called before using this function. |
---|
| 755 | const PredMap &predMap() const { return *_pred; } |
---|
| 756 | |
---|
| 757 | /// \brief Checks if a node is reachable from the root. |
---|
| 758 | /// |
---|
| 759 | /// Returns \c true if \c v is reachable from the root. |
---|
| 760 | /// \pre \ref run() must be called before using this function. |
---|
| 761 | /// |
---|
| 762 | bool reached(Node v) { return (*_dist)[v] != OperationTraits::infinity(); } |
---|
| 763 | |
---|
| 764 | ///@} |
---|
| 765 | }; |
---|
| 766 | |
---|
[1864] | 767 | /// \brief Default traits class of BellmanFord function. |
---|
[1699] | 768 | /// |
---|
[1864] | 769 | /// Default traits class of BellmanFord function. |
---|
[1699] | 770 | /// \param _Graph Graph type. |
---|
| 771 | /// \param _LengthMap Type of length map. |
---|
| 772 | template <typename _Graph, typename _LengthMap> |
---|
[1864] | 773 | struct BellmanFordWizardDefaultTraits { |
---|
[1699] | 774 | /// \brief The graph type the algorithm runs on. |
---|
| 775 | typedef _Graph Graph; |
---|
| 776 | |
---|
| 777 | /// \brief The type of the map that stores the edge lengths. |
---|
| 778 | /// |
---|
| 779 | /// The type of the map that stores the edge lengths. |
---|
[2260] | 780 | /// It must meet the \ref concepts::ReadMap "ReadMap" concept. |
---|
[1699] | 781 | typedef _LengthMap LengthMap; |
---|
| 782 | |
---|
| 783 | /// \brief The value type of the length map. |
---|
| 784 | typedef typename _LengthMap::Value Value; |
---|
| 785 | |
---|
[1864] | 786 | /// \brief Operation traits for bellman-ford algorithm. |
---|
[1699] | 787 | /// |
---|
| 788 | /// It defines the infinity type on the given Value type |
---|
| 789 | /// and the used operation. |
---|
[1864] | 790 | /// \see BellmanFordDefaultOperationTraits |
---|
| 791 | typedef BellmanFordDefaultOperationTraits<Value> OperationTraits; |
---|
[1699] | 792 | |
---|
| 793 | /// \brief The type of the map that stores the last |
---|
| 794 | /// edges of the shortest paths. |
---|
| 795 | /// |
---|
| 796 | /// The type of the map that stores the last |
---|
| 797 | /// edges of the shortest paths. |
---|
[2260] | 798 | /// It must meet the \ref concepts::WriteMap "WriteMap" concept. |
---|
[1699] | 799 | typedef NullMap <typename _Graph::Node,typename _Graph::Edge> PredMap; |
---|
| 800 | |
---|
| 801 | /// \brief Instantiates a PredMap. |
---|
| 802 | /// |
---|
| 803 | /// This function instantiates a \ref PredMap. |
---|
| 804 | static PredMap *createPredMap(const _Graph &) { |
---|
| 805 | return new PredMap(); |
---|
| 806 | } |
---|
| 807 | /// \brief The type of the map that stores the dists of the nodes. |
---|
| 808 | /// |
---|
| 809 | /// The type of the map that stores the dists of the nodes. |
---|
[2260] | 810 | /// It must meet the \ref concepts::WriteMap "WriteMap" concept. |
---|
[1699] | 811 | typedef NullMap<typename Graph::Node, Value> DistMap; |
---|
| 812 | /// \brief Instantiates a DistMap. |
---|
| 813 | /// |
---|
| 814 | /// This function instantiates a \ref DistMap. |
---|
| 815 | static DistMap *createDistMap(const _Graph &) { |
---|
| 816 | return new DistMap(); |
---|
| 817 | } |
---|
| 818 | }; |
---|
| 819 | |
---|
[1864] | 820 | /// \brief Default traits used by \ref BellmanFordWizard |
---|
[1699] | 821 | /// |
---|
[1864] | 822 | /// To make it easier to use BellmanFord algorithm |
---|
[1699] | 823 | /// we have created a wizard class. |
---|
[1864] | 824 | /// This \ref BellmanFordWizard class needs default traits, |
---|
| 825 | /// as well as the \ref BellmanFord class. |
---|
| 826 | /// The \ref BellmanFordWizardBase is a class to be the default traits of the |
---|
| 827 | /// \ref BellmanFordWizard class. |
---|
[1699] | 828 | /// \todo More named parameters are required... |
---|
| 829 | template<class _Graph,class _LengthMap> |
---|
[1864] | 830 | class BellmanFordWizardBase |
---|
| 831 | : public BellmanFordWizardDefaultTraits<_Graph,_LengthMap> { |
---|
[1699] | 832 | |
---|
[1864] | 833 | typedef BellmanFordWizardDefaultTraits<_Graph,_LengthMap> Base; |
---|
[1699] | 834 | protected: |
---|
| 835 | /// Type of the nodes in the graph. |
---|
| 836 | typedef typename Base::Graph::Node Node; |
---|
| 837 | |
---|
| 838 | /// Pointer to the underlying graph. |
---|
| 839 | void *_graph; |
---|
| 840 | /// Pointer to the length map |
---|
| 841 | void *_length; |
---|
| 842 | ///Pointer to the map of predecessors edges. |
---|
| 843 | void *_pred; |
---|
| 844 | ///Pointer to the map of distances. |
---|
| 845 | void *_dist; |
---|
| 846 | ///Pointer to the source node. |
---|
| 847 | Node _source; |
---|
| 848 | |
---|
| 849 | public: |
---|
| 850 | /// Constructor. |
---|
| 851 | |
---|
| 852 | /// This constructor does not require parameters, therefore it initiates |
---|
| 853 | /// all of the attributes to default values (0, INVALID). |
---|
[1864] | 854 | BellmanFordWizardBase() : _graph(0), _length(0), _pred(0), |
---|
[1699] | 855 | _dist(0), _source(INVALID) {} |
---|
| 856 | |
---|
| 857 | /// Constructor. |
---|
| 858 | |
---|
| 859 | /// This constructor requires some parameters, |
---|
| 860 | /// listed in the parameters list. |
---|
| 861 | /// Others are initiated to 0. |
---|
| 862 | /// \param graph is the initial value of \ref _graph |
---|
| 863 | /// \param length is the initial value of \ref _length |
---|
| 864 | /// \param source is the initial value of \ref _source |
---|
[1864] | 865 | BellmanFordWizardBase(const _Graph& graph, |
---|
[1699] | 866 | const _LengthMap& length, |
---|
| 867 | Node source = INVALID) : |
---|
| 868 | _graph((void *)&graph), _length((void *)&length), _pred(0), |
---|
| 869 | _dist(0), _source(source) {} |
---|
| 870 | |
---|
| 871 | }; |
---|
| 872 | |
---|
[1864] | 873 | /// A class to make the usage of BellmanFord algorithm easier |
---|
[1699] | 874 | |
---|
[1864] | 875 | /// This class is created to make it easier to use BellmanFord algorithm. |
---|
| 876 | /// It uses the functions and features of the plain \ref BellmanFord, |
---|
[1699] | 877 | /// but it is much simpler to use it. |
---|
| 878 | /// |
---|
| 879 | /// Simplicity means that the way to change the types defined |
---|
| 880 | /// in the traits class is based on functions that returns the new class |
---|
| 881 | /// and not on templatable built-in classes. |
---|
[1864] | 882 | /// When using the plain \ref BellmanFord |
---|
[1699] | 883 | /// the new class with the modified type comes from |
---|
| 884 | /// the original class by using the :: |
---|
[1864] | 885 | /// operator. In the case of \ref BellmanFordWizard only |
---|
[1699] | 886 | /// a function have to be called and it will |
---|
| 887 | /// return the needed class. |
---|
| 888 | /// |
---|
| 889 | /// It does not have own \ref run method. When its \ref run method is called |
---|
[1864] | 890 | /// it initiates a plain \ref BellmanFord class, and calls the \ref |
---|
| 891 | /// BellmanFord::run method of it. |
---|
[1699] | 892 | template<class _Traits> |
---|
[1864] | 893 | class BellmanFordWizard : public _Traits { |
---|
[1699] | 894 | typedef _Traits Base; |
---|
| 895 | |
---|
| 896 | ///The type of the underlying graph. |
---|
| 897 | typedef typename _Traits::Graph Graph; |
---|
| 898 | |
---|
| 899 | typedef typename Graph::Node Node; |
---|
| 900 | typedef typename Graph::NodeIt NodeIt; |
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| 901 | typedef typename Graph::Edge Edge; |
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| 902 | typedef typename Graph::OutEdgeIt EdgeIt; |
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| 903 | |
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| 904 | ///The type of the map that stores the edge lengths. |
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| 905 | typedef typename _Traits::LengthMap LengthMap; |
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| 906 | |
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| 907 | ///The type of the length of the edges. |
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| 908 | typedef typename LengthMap::Value Value; |
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| 909 | |
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| 910 | ///\brief The type of the map that stores the last |
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| 911 | ///edges of the shortest paths. |
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| 912 | typedef typename _Traits::PredMap PredMap; |
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| 913 | |
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| 914 | ///The type of the map that stores the dists of the nodes. |
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| 915 | typedef typename _Traits::DistMap DistMap; |
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| 916 | |
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| 917 | public: |
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| 918 | /// Constructor. |
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[1864] | 919 | BellmanFordWizard() : _Traits() {} |
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[1699] | 920 | |
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| 921 | /// \brief Constructor that requires parameters. |
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| 922 | /// |
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| 923 | /// Constructor that requires parameters. |
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| 924 | /// These parameters will be the default values for the traits class. |
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[1864] | 925 | BellmanFordWizard(const Graph& graph, const LengthMap& length, |
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[1699] | 926 | Node source = INVALID) |
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| 927 | : _Traits(graph, length, source) {} |
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| 928 | |
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| 929 | /// \brief Copy constructor |
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[1864] | 930 | BellmanFordWizard(const _Traits &b) : _Traits(b) {} |
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[1699] | 931 | |
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[1864] | 932 | ~BellmanFordWizard() {} |
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[1699] | 933 | |
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[1864] | 934 | /// \brief Runs BellmanFord algorithm from a given node. |
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[1699] | 935 | /// |
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[1864] | 936 | /// Runs BellmanFord algorithm from a given node. |
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[1699] | 937 | /// The node can be given by the \ref source function. |
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| 938 | void run() { |
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| 939 | if(Base::_source == INVALID) throw UninitializedParameter(); |
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[1864] | 940 | BellmanFord<Graph,LengthMap,_Traits> |
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[1699] | 941 | bf(*(Graph*)Base::_graph, *(LengthMap*)Base::_length); |
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| 942 | if (Base::_pred) bf.predMap(*(PredMap*)Base::_pred); |
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| 943 | if (Base::_dist) bf.distMap(*(DistMap*)Base::_dist); |
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| 944 | bf.run(Base::_source); |
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| 945 | } |
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| 946 | |
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[1864] | 947 | /// \brief Runs BellmanFord algorithm from the given node. |
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[1699] | 948 | /// |
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[1864] | 949 | /// Runs BellmanFord algorithm from the given node. |
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[1858] | 950 | /// \param source is the given source. |
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[1699] | 951 | void run(Node source) { |
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| 952 | Base::_source = source; |
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| 953 | run(); |
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| 954 | } |
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| 955 | |
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| 956 | template<class T> |
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| 957 | struct DefPredMapBase : public Base { |
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| 958 | typedef T PredMap; |
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| 959 | static PredMap *createPredMap(const Graph &) { return 0; }; |
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| 960 | DefPredMapBase(const _Traits &b) : _Traits(b) {} |
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| 961 | }; |
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| 962 | |
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| 963 | ///\brief \ref named-templ-param "Named parameter" |
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| 964 | ///function for setting PredMap type |
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| 965 | /// |
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| 966 | /// \ref named-templ-param "Named parameter" |
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| 967 | ///function for setting PredMap type |
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| 968 | /// |
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| 969 | template<class T> |
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[1864] | 970 | BellmanFordWizard<DefPredMapBase<T> > predMap(const T &t) |
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[1699] | 971 | { |
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| 972 | Base::_pred=(void *)&t; |
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[1864] | 973 | return BellmanFordWizard<DefPredMapBase<T> >(*this); |
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[1699] | 974 | } |
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| 975 | |
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| 976 | template<class T> |
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| 977 | struct DefDistMapBase : public Base { |
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| 978 | typedef T DistMap; |
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| 979 | static DistMap *createDistMap(const Graph &) { return 0; }; |
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| 980 | DefDistMapBase(const _Traits &b) : _Traits(b) {} |
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| 981 | }; |
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| 982 | |
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| 983 | ///\brief \ref named-templ-param "Named parameter" |
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| 984 | ///function for setting DistMap type |
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| 985 | /// |
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| 986 | /// \ref named-templ-param "Named parameter" |
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| 987 | ///function for setting DistMap type |
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| 988 | /// |
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| 989 | template<class T> |
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[1864] | 990 | BellmanFordWizard<DefDistMapBase<T> > distMap(const T &t) { |
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[1699] | 991 | Base::_dist=(void *)&t; |
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[1864] | 992 | return BellmanFordWizard<DefDistMapBase<T> >(*this); |
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[1699] | 993 | } |
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[1710] | 994 | |
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| 995 | template<class T> |
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| 996 | struct DefOperationTraitsBase : public Base { |
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| 997 | typedef T OperationTraits; |
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| 998 | DefOperationTraitsBase(const _Traits &b) : _Traits(b) {} |
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| 999 | }; |
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| 1000 | |
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| 1001 | ///\brief \ref named-templ-param "Named parameter" |
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| 1002 | ///function for setting OperationTraits type |
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| 1003 | /// |
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| 1004 | /// \ref named-templ-param "Named parameter" |
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| 1005 | ///function for setting OperationTraits type |
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| 1006 | /// |
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| 1007 | template<class T> |
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[1864] | 1008 | BellmanFordWizard<DefOperationTraitsBase<T> > distMap() { |
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| 1009 | return BellmanFordWizard<DefDistMapBase<T> >(*this); |
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[1710] | 1010 | } |
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[1699] | 1011 | |
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[1864] | 1012 | /// \brief Sets the source node, from which the BellmanFord algorithm runs. |
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[1699] | 1013 | /// |
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[1864] | 1014 | /// Sets the source node, from which the BellmanFord algorithm runs. |
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[1858] | 1015 | /// \param source is the source node. |
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[1864] | 1016 | BellmanFordWizard<_Traits>& source(Node source) { |
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[1699] | 1017 | Base::_source = source; |
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| 1018 | return *this; |
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| 1019 | } |
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| 1020 | |
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| 1021 | }; |
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| 1022 | |
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[1864] | 1023 | /// \brief Function type interface for BellmanFord algorithm. |
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[1699] | 1024 | /// |
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| 1025 | /// \ingroup flowalgs |
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[1864] | 1026 | /// Function type interface for BellmanFord algorithm. |
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[1699] | 1027 | /// |
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| 1028 | /// This function also has several \ref named-templ-func-param |
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| 1029 | /// "named parameters", they are declared as the members of class |
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[1864] | 1030 | /// \ref BellmanFordWizard. |
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[1699] | 1031 | /// The following |
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| 1032 | /// example shows how to use these parameters. |
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[1946] | 1033 | ///\code |
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[1864] | 1034 | /// bellmanford(g,length,source).predMap(preds).run(); |
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[1946] | 1035 | ///\endcode |
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[1864] | 1036 | /// \warning Don't forget to put the \ref BellmanFordWizard::run() "run()" |
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[1699] | 1037 | /// to the end of the parameter list. |
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[1864] | 1038 | /// \sa BellmanFordWizard |
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| 1039 | /// \sa BellmanFord |
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[1699] | 1040 | template<class _Graph, class _LengthMap> |
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[1864] | 1041 | BellmanFordWizard<BellmanFordWizardBase<_Graph,_LengthMap> > |
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| 1042 | bellmanFord(const _Graph& graph, |
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[1699] | 1043 | const _LengthMap& length, |
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| 1044 | typename _Graph::Node source = INVALID) { |
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[1864] | 1045 | return BellmanFordWizard<BellmanFordWizardBase<_Graph,_LengthMap> > |
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[1699] | 1046 | (graph, length, source); |
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| 1047 | } |
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| 1048 | |
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| 1049 | } //END OF NAMESPACE LEMON |
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| 1050 | |
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| 1051 | #endif |
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| 1052 | |
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