[956] | 1 | /* -*- mode: C++; indent-tabs-mode: nil; -*- |
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[813] | 2 | * |
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[956] | 3 | * This file is a part of LEMON, a generic C++ optimization library. |
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[813] | 4 | * |
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[1270] | 5 | * Copyright (C) 2003-2013 |
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[813] | 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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[942] | 19 | #ifndef LEMON_HARTMANN_ORLIN_MMC_H |
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| 20 | #define LEMON_HARTMANN_ORLIN_MMC_H |
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[813] | 21 | |
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[815] | 22 | /// \ingroup min_mean_cycle |
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[813] | 23 | /// |
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| 24 | /// \file |
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| 25 | /// \brief Hartmann-Orlin's algorithm for finding a minimum mean cycle. |
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| 26 | |
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| 27 | #include <vector> |
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| 28 | #include <limits> |
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| 29 | #include <lemon/core.h> |
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| 30 | #include <lemon/path.h> |
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| 31 | #include <lemon/tolerance.h> |
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| 32 | #include <lemon/connectivity.h> |
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| 33 | |
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| 34 | namespace lemon { |
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| 35 | |
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[942] | 36 | /// \brief Default traits class of HartmannOrlinMmc class. |
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[813] | 37 | /// |
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[942] | 38 | /// Default traits class of HartmannOrlinMmc class. |
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[813] | 39 | /// \tparam GR The type of the digraph. |
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[942] | 40 | /// \tparam CM The type of the cost map. |
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[959] | 41 | /// It must conform to the \ref concepts::ReadMap "ReadMap" concept. |
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[813] | 42 | #ifdef DOXYGEN |
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[942] | 43 | template <typename GR, typename CM> |
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[813] | 44 | #else |
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[942] | 45 | template <typename GR, typename CM, |
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| 46 | bool integer = std::numeric_limits<typename CM::Value>::is_integer> |
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[813] | 47 | #endif |
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[942] | 48 | struct HartmannOrlinMmcDefaultTraits |
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[813] | 49 | { |
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| 50 | /// The type of the digraph |
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| 51 | typedef GR Digraph; |
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[942] | 52 | /// The type of the cost map |
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| 53 | typedef CM CostMap; |
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| 54 | /// The type of the arc costs |
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| 55 | typedef typename CostMap::Value Cost; |
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[813] | 56 | |
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[942] | 57 | /// \brief The large cost type used for internal computations |
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[813] | 58 | /// |
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[942] | 59 | /// The large cost type used for internal computations. |
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| 60 | /// It is \c long \c long if the \c Cost type is integer, |
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[813] | 61 | /// otherwise it is \c double. |
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[942] | 62 | /// \c Cost must be convertible to \c LargeCost. |
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| 63 | typedef double LargeCost; |
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[813] | 64 | |
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| 65 | /// The tolerance type used for internal computations |
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[942] | 66 | typedef lemon::Tolerance<LargeCost> Tolerance; |
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[813] | 67 | |
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| 68 | /// \brief The path type of the found cycles |
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| 69 | /// |
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| 70 | /// The path type of the found cycles. |
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| 71 | /// It must conform to the \ref lemon::concepts::Path "Path" concept |
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[819] | 72 | /// and it must have an \c addFront() function. |
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[813] | 73 | typedef lemon::Path<Digraph> Path; |
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| 74 | }; |
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| 75 | |
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[942] | 76 | // Default traits class for integer cost types |
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| 77 | template <typename GR, typename CM> |
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| 78 | struct HartmannOrlinMmcDefaultTraits<GR, CM, true> |
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[813] | 79 | { |
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| 80 | typedef GR Digraph; |
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[942] | 81 | typedef CM CostMap; |
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| 82 | typedef typename CostMap::Value Cost; |
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[813] | 83 | #ifdef LEMON_HAVE_LONG_LONG |
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[942] | 84 | typedef long long LargeCost; |
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[813] | 85 | #else |
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[942] | 86 | typedef long LargeCost; |
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[813] | 87 | #endif |
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[942] | 88 | typedef lemon::Tolerance<LargeCost> Tolerance; |
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[813] | 89 | typedef lemon::Path<Digraph> Path; |
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| 90 | }; |
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| 91 | |
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| 92 | |
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[815] | 93 | /// \addtogroup min_mean_cycle |
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[813] | 94 | /// @{ |
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| 95 | |
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| 96 | /// \brief Implementation of the Hartmann-Orlin algorithm for finding |
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| 97 | /// a minimum mean cycle. |
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| 98 | /// |
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| 99 | /// This class implements the Hartmann-Orlin algorithm for finding |
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[942] | 100 | /// a directed cycle of minimum mean cost in a digraph |
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[1221] | 101 | /// \cite hartmann93finding, \cite dasdan98minmeancycle. |
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[1217] | 102 | /// This method is based on \ref KarpMmc "Karp"'s original algorithm, but |
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| 103 | /// applies an early termination scheme. It makes the algorithm |
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| 104 | /// significantly faster for some problem instances, but slower for others. |
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[1254] | 105 | /// The algorithm runs in time O(nm) and uses space O(n<sup>2</sup>+m). |
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[813] | 106 | /// |
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| 107 | /// \tparam GR The type of the digraph the algorithm runs on. |
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[942] | 108 | /// \tparam CM The type of the cost map. The default |
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[813] | 109 | /// map type is \ref concepts::Digraph::ArcMap "GR::ArcMap<int>". |
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[891] | 110 | /// \tparam TR The traits class that defines various types used by the |
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[942] | 111 | /// algorithm. By default, it is \ref HartmannOrlinMmcDefaultTraits |
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| 112 | /// "HartmannOrlinMmcDefaultTraits<GR, CM>". |
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[891] | 113 | /// In most cases, this parameter should not be set directly, |
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| 114 | /// consider to use the named template parameters instead. |
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[813] | 115 | #ifdef DOXYGEN |
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[942] | 116 | template <typename GR, typename CM, typename TR> |
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[813] | 117 | #else |
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| 118 | template < typename GR, |
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[942] | 119 | typename CM = typename GR::template ArcMap<int>, |
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| 120 | typename TR = HartmannOrlinMmcDefaultTraits<GR, CM> > |
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[813] | 121 | #endif |
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[942] | 122 | class HartmannOrlinMmc |
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[813] | 123 | { |
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| 124 | public: |
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| 125 | |
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| 126 | /// The type of the digraph |
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| 127 | typedef typename TR::Digraph Digraph; |
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[942] | 128 | /// The type of the cost map |
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| 129 | typedef typename TR::CostMap CostMap; |
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| 130 | /// The type of the arc costs |
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| 131 | typedef typename TR::Cost Cost; |
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[813] | 132 | |
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[942] | 133 | /// \brief The large cost type |
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[813] | 134 | /// |
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[942] | 135 | /// The large cost type used for internal computations. |
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| 136 | /// By default, it is \c long \c long if the \c Cost type is integer, |
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[813] | 137 | /// otherwise it is \c double. |
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[942] | 138 | typedef typename TR::LargeCost LargeCost; |
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[813] | 139 | |
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| 140 | /// The tolerance type |
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| 141 | typedef typename TR::Tolerance Tolerance; |
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| 142 | |
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| 143 | /// \brief The path type of the found cycles |
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| 144 | /// |
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| 145 | /// The path type of the found cycles. |
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[1250] | 146 | /// Using the \ref lemon::HartmannOrlinMmcDefaultTraits |
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| 147 | /// "default traits class", |
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[813] | 148 | /// it is \ref lemon::Path "Path<Digraph>". |
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| 149 | typedef typename TR::Path Path; |
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| 150 | |
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[1250] | 151 | /// \brief The |
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| 152 | /// \ref lemon::HartmannOrlinMmcDefaultTraits "traits class" |
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| 153 | /// of the algorithm |
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[813] | 154 | typedef TR Traits; |
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| 155 | |
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| 156 | private: |
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| 157 | |
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| 158 | TEMPLATE_DIGRAPH_TYPEDEFS(Digraph); |
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| 159 | |
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| 160 | // Data sturcture for path data |
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| 161 | struct PathData |
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| 162 | { |
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[942] | 163 | LargeCost dist; |
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[813] | 164 | Arc pred; |
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[942] | 165 | PathData(LargeCost d, Arc p = INVALID) : |
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[814] | 166 | dist(d), pred(p) {} |
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[813] | 167 | }; |
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| 168 | |
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| 169 | typedef typename Digraph::template NodeMap<std::vector<PathData> > |
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| 170 | PathDataNodeMap; |
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| 171 | |
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| 172 | private: |
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| 173 | |
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| 174 | // The digraph the algorithm runs on |
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| 175 | const Digraph &_gr; |
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[942] | 176 | // The cost of the arcs |
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| 177 | const CostMap &_cost; |
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[813] | 178 | |
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| 179 | // Data for storing the strongly connected components |
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| 180 | int _comp_num; |
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| 181 | typename Digraph::template NodeMap<int> _comp; |
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| 182 | std::vector<std::vector<Node> > _comp_nodes; |
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| 183 | std::vector<Node>* _nodes; |
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| 184 | typename Digraph::template NodeMap<std::vector<Arc> > _out_arcs; |
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| 185 | |
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| 186 | // Data for the found cycles |
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| 187 | bool _curr_found, _best_found; |
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[942] | 188 | LargeCost _curr_cost, _best_cost; |
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[813] | 189 | int _curr_size, _best_size; |
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| 190 | Node _curr_node, _best_node; |
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| 191 | int _curr_level, _best_level; |
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| 192 | |
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| 193 | Path *_cycle_path; |
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| 194 | bool _local_path; |
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| 195 | |
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| 196 | // Node map for storing path data |
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| 197 | PathDataNodeMap _data; |
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| 198 | // The processed nodes in the last round |
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| 199 | std::vector<Node> _process; |
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| 200 | |
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| 201 | Tolerance _tolerance; |
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| 202 | |
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[814] | 203 | // Infinite constant |
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[942] | 204 | const LargeCost INF; |
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[814] | 205 | |
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[813] | 206 | public: |
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| 207 | |
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| 208 | /// \name Named Template Parameters |
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| 209 | /// @{ |
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| 210 | |
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| 211 | template <typename T> |
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[942] | 212 | struct SetLargeCostTraits : public Traits { |
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| 213 | typedef T LargeCost; |
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[813] | 214 | typedef lemon::Tolerance<T> Tolerance; |
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| 215 | }; |
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| 216 | |
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| 217 | /// \brief \ref named-templ-param "Named parameter" for setting |
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[942] | 218 | /// \c LargeCost type. |
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[813] | 219 | /// |
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[942] | 220 | /// \ref named-templ-param "Named parameter" for setting \c LargeCost |
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[813] | 221 | /// type. It is used for internal computations in the algorithm. |
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| 222 | template <typename T> |
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[942] | 223 | struct SetLargeCost |
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| 224 | : public HartmannOrlinMmc<GR, CM, SetLargeCostTraits<T> > { |
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| 225 | typedef HartmannOrlinMmc<GR, CM, SetLargeCostTraits<T> > Create; |
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[813] | 226 | }; |
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| 227 | |
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| 228 | template <typename T> |
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| 229 | struct SetPathTraits : public Traits { |
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| 230 | typedef T Path; |
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| 231 | }; |
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| 232 | |
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| 233 | /// \brief \ref named-templ-param "Named parameter" for setting |
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| 234 | /// \c %Path type. |
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| 235 | /// |
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| 236 | /// \ref named-templ-param "Named parameter" for setting the \c %Path |
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| 237 | /// type of the found cycles. |
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| 238 | /// It must conform to the \ref lemon::concepts::Path "Path" concept |
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| 239 | /// and it must have an \c addFront() function. |
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| 240 | template <typename T> |
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| 241 | struct SetPath |
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[942] | 242 | : public HartmannOrlinMmc<GR, CM, SetPathTraits<T> > { |
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| 243 | typedef HartmannOrlinMmc<GR, CM, SetPathTraits<T> > Create; |
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[813] | 244 | }; |
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| 245 | |
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| 246 | /// @} |
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| 247 | |
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[941] | 248 | protected: |
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| 249 | |
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[942] | 250 | HartmannOrlinMmc() {} |
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[941] | 251 | |
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[813] | 252 | public: |
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| 253 | |
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| 254 | /// \brief Constructor. |
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| 255 | /// |
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| 256 | /// The constructor of the class. |
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| 257 | /// |
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| 258 | /// \param digraph The digraph the algorithm runs on. |
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[942] | 259 | /// \param cost The costs of the arcs. |
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| 260 | HartmannOrlinMmc( const Digraph &digraph, |
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| 261 | const CostMap &cost ) : |
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| 262 | _gr(digraph), _cost(cost), _comp(digraph), _out_arcs(digraph), |
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| 263 | _best_found(false), _best_cost(0), _best_size(1), |
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[814] | 264 | _cycle_path(NULL), _local_path(false), _data(digraph), |
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[942] | 265 | INF(std::numeric_limits<LargeCost>::has_infinity ? |
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| 266 | std::numeric_limits<LargeCost>::infinity() : |
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| 267 | std::numeric_limits<LargeCost>::max()) |
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[813] | 268 | {} |
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| 269 | |
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| 270 | /// Destructor. |
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[942] | 271 | ~HartmannOrlinMmc() { |
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[813] | 272 | if (_local_path) delete _cycle_path; |
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| 273 | } |
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| 274 | |
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| 275 | /// \brief Set the path structure for storing the found cycle. |
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| 276 | /// |
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| 277 | /// This function sets an external path structure for storing the |
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| 278 | /// found cycle. |
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| 279 | /// |
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| 280 | /// If you don't call this function before calling \ref run() or |
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[1217] | 281 | /// \ref findCycleMean(), a local \ref Path "path" structure |
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| 282 | /// will be allocated. The destuctor deallocates this automatically |
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[813] | 283 | /// allocated object, of course. |
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| 284 | /// |
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| 285 | /// \note The algorithm calls only the \ref lemon::Path::addFront() |
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| 286 | /// "addFront()" function of the given path structure. |
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| 287 | /// |
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| 288 | /// \return <tt>(*this)</tt> |
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[942] | 289 | HartmannOrlinMmc& cycle(Path &path) { |
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[813] | 290 | if (_local_path) { |
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| 291 | delete _cycle_path; |
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| 292 | _local_path = false; |
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| 293 | } |
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| 294 | _cycle_path = &path; |
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| 295 | return *this; |
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| 296 | } |
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| 297 | |
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[816] | 298 | /// \brief Set the tolerance used by the algorithm. |
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| 299 | /// |
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| 300 | /// This function sets the tolerance object used by the algorithm. |
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| 301 | /// |
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| 302 | /// \return <tt>(*this)</tt> |
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[942] | 303 | HartmannOrlinMmc& tolerance(const Tolerance& tolerance) { |
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[816] | 304 | _tolerance = tolerance; |
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| 305 | return *this; |
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| 306 | } |
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| 307 | |
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| 308 | /// \brief Return a const reference to the tolerance. |
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| 309 | /// |
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| 310 | /// This function returns a const reference to the tolerance object |
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| 311 | /// used by the algorithm. |
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| 312 | const Tolerance& tolerance() const { |
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| 313 | return _tolerance; |
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| 314 | } |
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| 315 | |
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[813] | 316 | /// \name Execution control |
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| 317 | /// The simplest way to execute the algorithm is to call the \ref run() |
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| 318 | /// function.\n |
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[942] | 319 | /// If you only need the minimum mean cost, you may call |
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| 320 | /// \ref findCycleMean(). |
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[813] | 321 | |
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| 322 | /// @{ |
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| 323 | |
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| 324 | /// \brief Run the algorithm. |
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| 325 | /// |
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| 326 | /// This function runs the algorithm. |
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| 327 | /// It can be called more than once (e.g. if the underlying digraph |
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[942] | 328 | /// and/or the arc costs have been modified). |
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[813] | 329 | /// |
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| 330 | /// \return \c true if a directed cycle exists in the digraph. |
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| 331 | /// |
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| 332 | /// \note <tt>mmc.run()</tt> is just a shortcut of the following code. |
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| 333 | /// \code |
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[942] | 334 | /// return mmc.findCycleMean() && mmc.findCycle(); |
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[813] | 335 | /// \endcode |
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| 336 | bool run() { |
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[942] | 337 | return findCycleMean() && findCycle(); |
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[813] | 338 | } |
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| 339 | |
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| 340 | /// \brief Find the minimum cycle mean. |
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| 341 | /// |
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[942] | 342 | /// This function finds the minimum mean cost of the directed |
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[813] | 343 | /// cycles in the digraph. |
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| 344 | /// |
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| 345 | /// \return \c true if a directed cycle exists in the digraph. |
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[942] | 346 | bool findCycleMean() { |
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[813] | 347 | // Initialization and find strongly connected components |
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| 348 | init(); |
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| 349 | findComponents(); |
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[956] | 350 | |
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[813] | 351 | // Find the minimum cycle mean in the components |
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| 352 | for (int comp = 0; comp < _comp_num; ++comp) { |
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| 353 | if (!initComponent(comp)) continue; |
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| 354 | processRounds(); |
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[956] | 355 | |
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[813] | 356 | // Update the best cycle (global minimum mean cycle) |
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[956] | 357 | if ( _curr_found && (!_best_found || |
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[942] | 358 | _curr_cost * _best_size < _best_cost * _curr_size) ) { |
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[813] | 359 | _best_found = true; |
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[942] | 360 | _best_cost = _curr_cost; |
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[813] | 361 | _best_size = _curr_size; |
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| 362 | _best_node = _curr_node; |
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| 363 | _best_level = _curr_level; |
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| 364 | } |
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| 365 | } |
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| 366 | return _best_found; |
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| 367 | } |
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| 368 | |
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| 369 | /// \brief Find a minimum mean directed cycle. |
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| 370 | /// |
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[942] | 371 | /// This function finds a directed cycle of minimum mean cost |
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| 372 | /// in the digraph using the data computed by findCycleMean(). |
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[813] | 373 | /// |
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| 374 | /// \return \c true if a directed cycle exists in the digraph. |
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| 375 | /// |
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[942] | 376 | /// \pre \ref findCycleMean() must be called before using this function. |
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[813] | 377 | bool findCycle() { |
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| 378 | if (!_best_found) return false; |
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| 379 | IntNodeMap reached(_gr, -1); |
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| 380 | int r = _best_level + 1; |
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| 381 | Node u = _best_node; |
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| 382 | while (reached[u] < 0) { |
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| 383 | reached[u] = --r; |
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| 384 | u = _gr.source(_data[u][r].pred); |
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| 385 | } |
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| 386 | r = reached[u]; |
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| 387 | Arc e = _data[u][r].pred; |
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| 388 | _cycle_path->addFront(e); |
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[942] | 389 | _best_cost = _cost[e]; |
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[813] | 390 | _best_size = 1; |
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| 391 | Node v; |
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| 392 | while ((v = _gr.source(e)) != u) { |
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| 393 | e = _data[v][--r].pred; |
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| 394 | _cycle_path->addFront(e); |
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[942] | 395 | _best_cost += _cost[e]; |
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[813] | 396 | ++_best_size; |
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| 397 | } |
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| 398 | return true; |
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| 399 | } |
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| 400 | |
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| 401 | /// @} |
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| 402 | |
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| 403 | /// \name Query Functions |
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| 404 | /// The results of the algorithm can be obtained using these |
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| 405 | /// functions.\n |
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| 406 | /// The algorithm should be executed before using them. |
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| 407 | |
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| 408 | /// @{ |
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| 409 | |
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[942] | 410 | /// \brief Return the total cost of the found cycle. |
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[813] | 411 | /// |
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[942] | 412 | /// This function returns the total cost of the found cycle. |
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[813] | 413 | /// |
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[942] | 414 | /// \pre \ref run() or \ref findCycleMean() must be called before |
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[813] | 415 | /// using this function. |
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[942] | 416 | Cost cycleCost() const { |
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| 417 | return static_cast<Cost>(_best_cost); |
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[813] | 418 | } |
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| 419 | |
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| 420 | /// \brief Return the number of arcs on the found cycle. |
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| 421 | /// |
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| 422 | /// This function returns the number of arcs on the found cycle. |
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| 423 | /// |
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[942] | 424 | /// \pre \ref run() or \ref findCycleMean() must be called before |
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[813] | 425 | /// using this function. |
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[942] | 426 | int cycleSize() const { |
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[813] | 427 | return _best_size; |
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| 428 | } |
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| 429 | |
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[942] | 430 | /// \brief Return the mean cost of the found cycle. |
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[813] | 431 | /// |
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[942] | 432 | /// This function returns the mean cost of the found cycle. |
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[813] | 433 | /// |
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| 434 | /// \note <tt>alg.cycleMean()</tt> is just a shortcut of the |
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| 435 | /// following code. |
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| 436 | /// \code |
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[942] | 437 | /// return static_cast<double>(alg.cycleCost()) / alg.cycleSize(); |
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[813] | 438 | /// \endcode |
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| 439 | /// |
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[942] | 440 | /// \pre \ref run() or \ref findCycleMean() must be called before |
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[813] | 441 | /// using this function. |
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| 442 | double cycleMean() const { |
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[942] | 443 | return static_cast<double>(_best_cost) / _best_size; |
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[813] | 444 | } |
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| 445 | |
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| 446 | /// \brief Return the found cycle. |
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| 447 | /// |
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| 448 | /// This function returns a const reference to the path structure |
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| 449 | /// storing the found cycle. |
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| 450 | /// |
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| 451 | /// \pre \ref run() or \ref findCycle() must be called before using |
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| 452 | /// this function. |
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| 453 | const Path& cycle() const { |
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| 454 | return *_cycle_path; |
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| 455 | } |
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| 456 | |
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| 457 | ///@} |
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| 458 | |
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| 459 | private: |
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| 460 | |
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| 461 | // Initialization |
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| 462 | void init() { |
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| 463 | if (!_cycle_path) { |
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| 464 | _local_path = true; |
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| 465 | _cycle_path = new Path; |
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| 466 | } |
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| 467 | _cycle_path->clear(); |
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| 468 | _best_found = false; |
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[942] | 469 | _best_cost = 0; |
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[813] | 470 | _best_size = 1; |
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| 471 | _cycle_path->clear(); |
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| 472 | for (NodeIt u(_gr); u != INVALID; ++u) |
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| 473 | _data[u].clear(); |
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| 474 | } |
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| 475 | |
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| 476 | // Find strongly connected components and initialize _comp_nodes |
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| 477 | // and _out_arcs |
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| 478 | void findComponents() { |
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| 479 | _comp_num = stronglyConnectedComponents(_gr, _comp); |
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| 480 | _comp_nodes.resize(_comp_num); |
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| 481 | if (_comp_num == 1) { |
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| 482 | _comp_nodes[0].clear(); |
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| 483 | for (NodeIt n(_gr); n != INVALID; ++n) { |
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| 484 | _comp_nodes[0].push_back(n); |
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| 485 | _out_arcs[n].clear(); |
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| 486 | for (OutArcIt a(_gr, n); a != INVALID; ++a) { |
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| 487 | _out_arcs[n].push_back(a); |
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| 488 | } |
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| 489 | } |
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| 490 | } else { |
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| 491 | for (int i = 0; i < _comp_num; ++i) |
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| 492 | _comp_nodes[i].clear(); |
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| 493 | for (NodeIt n(_gr); n != INVALID; ++n) { |
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| 494 | int k = _comp[n]; |
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| 495 | _comp_nodes[k].push_back(n); |
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| 496 | _out_arcs[n].clear(); |
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| 497 | for (OutArcIt a(_gr, n); a != INVALID; ++a) { |
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| 498 | if (_comp[_gr.target(a)] == k) _out_arcs[n].push_back(a); |
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| 499 | } |
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| 500 | } |
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| 501 | } |
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| 502 | } |
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| 503 | |
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| 504 | // Initialize path data for the current component |
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| 505 | bool initComponent(int comp) { |
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| 506 | _nodes = &(_comp_nodes[comp]); |
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| 507 | int n = _nodes->size(); |
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| 508 | if (n < 1 || (n == 1 && _out_arcs[(*_nodes)[0]].size() == 0)) { |
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| 509 | return false; |
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[956] | 510 | } |
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[813] | 511 | for (int i = 0; i < n; ++i) { |
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[814] | 512 | _data[(*_nodes)[i]].resize(n + 1, PathData(INF)); |
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[813] | 513 | } |
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| 514 | return true; |
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| 515 | } |
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| 516 | |
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| 517 | // Process all rounds of computing path data for the current component. |
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[942] | 518 | // _data[v][k] is the cost of a shortest directed walk from the root |
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[813] | 519 | // node to node v containing exactly k arcs. |
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| 520 | void processRounds() { |
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| 521 | Node start = (*_nodes)[0]; |
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[814] | 522 | _data[start][0] = PathData(0); |
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[813] | 523 | _process.clear(); |
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| 524 | _process.push_back(start); |
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| 525 | |
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| 526 | int k, n = _nodes->size(); |
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| 527 | int next_check = 4; |
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| 528 | bool terminate = false; |
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| 529 | for (k = 1; k <= n && int(_process.size()) < n && !terminate; ++k) { |
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| 530 | processNextBuildRound(k); |
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| 531 | if (k == next_check || k == n) { |
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| 532 | terminate = checkTermination(k); |
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| 533 | next_check = next_check * 3 / 2; |
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| 534 | } |
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| 535 | } |
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| 536 | for ( ; k <= n && !terminate; ++k) { |
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| 537 | processNextFullRound(k); |
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| 538 | if (k == next_check || k == n) { |
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| 539 | terminate = checkTermination(k); |
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| 540 | next_check = next_check * 3 / 2; |
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| 541 | } |
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| 542 | } |
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| 543 | } |
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| 544 | |
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| 545 | // Process one round and rebuild _process |
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| 546 | void processNextBuildRound(int k) { |
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| 547 | std::vector<Node> next; |
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| 548 | Node u, v; |
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| 549 | Arc e; |
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[942] | 550 | LargeCost d; |
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[813] | 551 | for (int i = 0; i < int(_process.size()); ++i) { |
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| 552 | u = _process[i]; |
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| 553 | for (int j = 0; j < int(_out_arcs[u].size()); ++j) { |
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| 554 | e = _out_arcs[u][j]; |
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| 555 | v = _gr.target(e); |
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[942] | 556 | d = _data[u][k-1].dist + _cost[e]; |
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[814] | 557 | if (_tolerance.less(d, _data[v][k].dist)) { |
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| 558 | if (_data[v][k].dist == INF) next.push_back(v); |
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| 559 | _data[v][k] = PathData(d, e); |
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[813] | 560 | } |
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| 561 | } |
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| 562 | } |
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| 563 | _process.swap(next); |
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| 564 | } |
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| 565 | |
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| 566 | // Process one round using _nodes instead of _process |
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| 567 | void processNextFullRound(int k) { |
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| 568 | Node u, v; |
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| 569 | Arc e; |
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[942] | 570 | LargeCost d; |
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[813] | 571 | for (int i = 0; i < int(_nodes->size()); ++i) { |
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| 572 | u = (*_nodes)[i]; |
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| 573 | for (int j = 0; j < int(_out_arcs[u].size()); ++j) { |
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| 574 | e = _out_arcs[u][j]; |
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| 575 | v = _gr.target(e); |
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[942] | 576 | d = _data[u][k-1].dist + _cost[e]; |
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[814] | 577 | if (_tolerance.less(d, _data[v][k].dist)) { |
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| 578 | _data[v][k] = PathData(d, e); |
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[813] | 579 | } |
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| 580 | } |
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| 581 | } |
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| 582 | } |
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[956] | 583 | |
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[813] | 584 | // Check early termination |
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| 585 | bool checkTermination(int k) { |
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| 586 | typedef std::pair<int, int> Pair; |
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| 587 | typename GR::template NodeMap<Pair> level(_gr, Pair(-1, 0)); |
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[942] | 588 | typename GR::template NodeMap<LargeCost> pi(_gr); |
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[813] | 589 | int n = _nodes->size(); |
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[942] | 590 | LargeCost cost; |
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[813] | 591 | int size; |
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| 592 | Node u; |
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[956] | 593 | |
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[813] | 594 | // Search for cycles that are already found |
---|
| 595 | _curr_found = false; |
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| 596 | for (int i = 0; i < n; ++i) { |
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| 597 | u = (*_nodes)[i]; |
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[814] | 598 | if (_data[u][k].dist == INF) continue; |
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[813] | 599 | for (int j = k; j >= 0; --j) { |
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| 600 | if (level[u].first == i && level[u].second > 0) { |
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| 601 | // A cycle is found |
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[942] | 602 | cost = _data[u][level[u].second].dist - _data[u][j].dist; |
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[813] | 603 | size = level[u].second - j; |
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[942] | 604 | if (!_curr_found || cost * _curr_size < _curr_cost * size) { |
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| 605 | _curr_cost = cost; |
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[813] | 606 | _curr_size = size; |
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| 607 | _curr_node = u; |
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| 608 | _curr_level = level[u].second; |
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| 609 | _curr_found = true; |
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| 610 | } |
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| 611 | } |
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| 612 | level[u] = Pair(i, j); |
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[859] | 613 | if (j != 0) { |
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[956] | 614 | u = _gr.source(_data[u][j].pred); |
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| 615 | } |
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[813] | 616 | } |
---|
| 617 | } |
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| 618 | |
---|
| 619 | // If at least one cycle is found, check the optimality condition |
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[942] | 620 | LargeCost d; |
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[813] | 621 | if (_curr_found && k < n) { |
---|
| 622 | // Find node potentials |
---|
| 623 | for (int i = 0; i < n; ++i) { |
---|
| 624 | u = (*_nodes)[i]; |
---|
[814] | 625 | pi[u] = INF; |
---|
[813] | 626 | for (int j = 0; j <= k; ++j) { |
---|
[814] | 627 | if (_data[u][j].dist < INF) { |
---|
[942] | 628 | d = _data[u][j].dist * _curr_size - j * _curr_cost; |
---|
[814] | 629 | if (_tolerance.less(d, pi[u])) pi[u] = d; |
---|
[813] | 630 | } |
---|
| 631 | } |
---|
| 632 | } |
---|
| 633 | |
---|
| 634 | // Check the optimality condition for all arcs |
---|
| 635 | bool done = true; |
---|
| 636 | for (ArcIt a(_gr); a != INVALID; ++a) { |
---|
[942] | 637 | if (_tolerance.less(_cost[a] * _curr_size - _curr_cost, |
---|
[813] | 638 | pi[_gr.target(a)] - pi[_gr.source(a)]) ) { |
---|
| 639 | done = false; |
---|
| 640 | break; |
---|
| 641 | } |
---|
| 642 | } |
---|
| 643 | return done; |
---|
| 644 | } |
---|
| 645 | return (k == n); |
---|
| 646 | } |
---|
| 647 | |
---|
[942] | 648 | }; //class HartmannOrlinMmc |
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[813] | 649 | |
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| 650 | ///@} |
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| 651 | |
---|
| 652 | } //namespace lemon |
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| 653 | |
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[942] | 654 | #endif //LEMON_HARTMANN_ORLIN_MMC_H |
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