| 1 | /* -*- mode: C++; indent-tabs-mode: nil; -*- |
| 2 | * |
| 3 | * This file is a part of LEMON, a generic C++ optimization library. |
| 4 | * |
| 5 | * Copyright (C) 2003-2008 |
| 6 | * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
| 7 | * (Egervary Research Group on Combinatorial Optimization, EGRES). |
| 8 | * |
| 9 | * Permission to use, modify and distribute this software is granted |
| 10 | * provided that this copyright notice appears in all copies. For |
| 11 | * precise terms see the accompanying LICENSE file. |
| 12 | * |
| 13 | * This software is provided "AS IS" with no warranty of any kind, |
| 14 | * express or implied, and with no claim as to its suitability for any |
| 15 | * purpose. |
| 16 | * |
| 17 | */ |
| 18 | |
| 19 | #ifndef HYPERCUBE_GRAPH_H |
| 20 | #define HYPERCUBE_GRAPH_H |
| 21 | |
| 22 | #include <iostream> |
| 23 | #include <vector> |
| 24 | #include <lemon/core.h> |
| 25 | #include <lemon/error.h> |
| 26 | |
| 27 | #include <lemon/bits/base_extender.h> |
| 28 | #include <lemon/bits/graph_extender.h> |
| 29 | |
| 30 | ///\ingroup graphs |
| 31 | ///\file |
| 32 | ///\brief HyperCubeDigraph class. |
| 33 | |
| 34 | namespace lemon { |
| 35 | |
| 36 | class HyperCubeDigraphBase { |
| 37 | |
| 38 | public: |
| 39 | |
| 40 | typedef HyperCubeDigraphBase Digraph; |
| 41 | |
| 42 | class Node; |
| 43 | class Arc; |
| 44 | |
| 45 | public: |
| 46 | |
| 47 | HyperCubeDigraphBase() {} |
| 48 | |
| 49 | protected: |
| 50 | |
| 51 | void construct(int dim) { |
| 52 | _dim = dim; |
| 53 | _nodeNum = 1 << dim; |
| 54 | } |
| 55 | |
| 56 | public: |
| 57 | |
| 58 | typedef True NodeNumTag; |
| 59 | typedef True ArcNumTag; |
| 60 | |
| 61 | int nodeNum() const { return _nodeNum; } |
| 62 | int arcNum() const { return _nodeNum * _dim; } |
| 63 | |
| 64 | int maxNodeId() const { return nodeNum() - 1; } |
| 65 | int maxArcId() const { return arcNum() - 1; } |
| 66 | |
| 67 | Node source(Arc e) const { |
| 68 | return e.id / _dim; |
| 69 | } |
| 70 | |
| 71 | Node target(Arc e) const { |
| 72 | return (e.id / _dim) ^ (1 << (e.id % _dim)); |
| 73 | } |
| 74 | |
| 75 | static int id(Node v) { return v.id; } |
| 76 | static int id(Arc e) { return e.id; } |
| 77 | |
| 78 | static Node nodeFromId(int id) { return Node(id); } |
| 79 | |
| 80 | static Arc arcFromId(int id) { return Arc(id); } |
| 81 | |
| 82 | class Node { |
| 83 | friend class HyperCubeDigraphBase; |
| 84 | protected: |
| 85 | int id; |
| 86 | Node(int _id) { id = _id;} |
| 87 | public: |
| 88 | Node() {} |
| 89 | Node (Invalid) { id = -1; } |
| 90 | bool operator==(const Node node) const { return id == node.id; } |
| 91 | bool operator!=(const Node node) const { return id != node.id; } |
| 92 | bool operator<(const Node node) const { return id < node.id; } |
| 93 | }; |
| 94 | |
| 95 | class Arc { |
| 96 | friend class HyperCubeDigraphBase; |
| 97 | protected: |
| 98 | int id; |
| 99 | Arc(int _id) : id(_id) {} |
| 100 | public: |
| 101 | Arc() { } |
| 102 | Arc (Invalid) { id = -1; } |
| 103 | bool operator==(const Arc arc) const { return id == arc.id; } |
| 104 | bool operator!=(const Arc arc) const { return id != arc.id; } |
| 105 | bool operator<(const Arc arc) const { return id < arc.id; } |
| 106 | }; |
| 107 | |
| 108 | void first(Node& node) const { |
| 109 | node.id = nodeNum() - 1; |
| 110 | } |
| 111 | |
| 112 | static void next(Node& node) { |
| 113 | --node.id; |
| 114 | } |
| 115 | |
| 116 | void first(Arc& arc) const { |
| 117 | arc.id = arcNum() - 1; |
| 118 | } |
| 119 | |
| 120 | static void next(Arc& arc) { |
| 121 | --arc.id; |
| 122 | } |
| 123 | |
| 124 | void firstOut(Arc& arc, const Node& node) const { |
| 125 | arc.id = node.id * _dim; |
| 126 | } |
| 127 | |
| 128 | void nextOut(Arc& arc) const { |
| 129 | ++arc.id; |
| 130 | if (arc.id % _dim == 0) arc.id = -1; |
| 131 | } |
| 132 | |
| 133 | void firstIn(Arc& arc, const Node& node) const { |
| 134 | arc.id = (node.id ^ 1) * _dim; |
| 135 | } |
| 136 | |
| 137 | void nextIn(Arc& arc) const { |
| 138 | int cnt = arc.id % _dim; |
| 139 | if ((cnt + 1) % _dim == 0) { |
| 140 | arc.id = -1; |
| 141 | } else { |
| 142 | arc.id = ((arc.id / _dim) ^ ((1 << cnt) * 3)) * _dim + cnt + 1; |
| 143 | } |
| 144 | } |
| 145 | |
| 146 | int dimension() const { |
| 147 | return _dim; |
| 148 | } |
| 149 | |
| 150 | bool projection(Node node, int n) const { |
| 151 | return static_cast<bool>(node.id & (1 << n)); |
| 152 | } |
| 153 | |
| 154 | int dimension(Arc arc) const { |
| 155 | return arc.id % _dim; |
| 156 | } |
| 157 | |
| 158 | int index(Node node) const { |
| 159 | return node.id; |
| 160 | } |
| 161 | |
| 162 | Node operator()(int ix) const { |
| 163 | return Node(ix); |
| 164 | } |
| 165 | |
| 166 | private: |
| 167 | int _dim, _nodeNum; |
| 168 | }; |
| 169 | |
| 170 | |
| 171 | typedef DigraphExtender<HyperCubeDigraphBase> ExtendedHyperCubeDigraphBase; |
| 172 | |
| 173 | /// \ingroup digraphs |
| 174 | /// |
| 175 | /// \brief Hypercube digraph class |
| 176 | /// |
| 177 | /// This class implements a special digraph type. The nodes of the |
| 178 | /// digraph are indiced with integers with at most \c dim binary digits. |
| 179 | /// Two nodes are connected in the digraph if the indices differ only |
| 180 | /// on one position in the binary form. |
| 181 | /// |
| 182 | /// \note The type of the \c ids is chosen to \c int because efficiency |
| 183 | /// reasons. Thus the maximum dimension of this implementation is 26. |
| 184 | /// |
| 185 | /// The digraph type is fully conform to the \ref concepts::Digraph |
| 186 | /// concept but it does not conform to \ref concepts::Graph. |
| 187 | class HyperCubeDigraph : public ExtendedHyperCubeDigraphBase { |
| 188 | public: |
| 189 | |
| 190 | typedef ExtendedHyperCubeDigraphBase Parent; |
| 191 | |
| 192 | /// \brief Construct a hypercube digraph with \c dim dimension. |
| 193 | /// |
| 194 | /// Construct a hypercube digraph with \c dim dimension. |
| 195 | HyperCubeDigraph(int dim) { construct(dim); } |
| 196 | |
| 197 | /// \brief Gives back the number of the dimensions. |
| 198 | /// |
| 199 | /// Gives back the number of the dimensions. |
| 200 | int dimension() const { |
| 201 | return Parent::dimension(); |
| 202 | } |
| 203 | |
| 204 | /// \brief Returns true if the n'th bit of the node is one. |
| 205 | /// |
| 206 | /// Returns true if the n'th bit of the node is one. |
| 207 | bool projection(Node node, int n) const { |
| 208 | return Parent::projection(node, n); |
| 209 | } |
| 210 | |
| 211 | /// \brief The dimension id of the arc. |
| 212 | /// |
| 213 | /// It returns the dimension id of the arc. It can |
| 214 | /// be in the \f$ \{0, 1, \dots, dim-1\} \f$ interval. |
| 215 | int dimension(Arc arc) const { |
| 216 | return Parent::dimension(arc); |
| 217 | } |
| 218 | |
| 219 | /// \brief Gives back the index of the node. |
| 220 | /// |
| 221 | /// Gives back the index of the node. The lower bits of the |
| 222 | /// integer describes the node. |
| 223 | int index(Node node) const { |
| 224 | return Parent::index(node); |
| 225 | } |
| 226 | |
| 227 | /// \brief Gives back the node by its index. |
| 228 | /// |
| 229 | /// Gives back the node by its index. |
| 230 | Node operator()(int ix) const { |
| 231 | return Parent::operator()(ix); |
| 232 | } |
| 233 | |
| 234 | /// \brief Number of nodes. |
| 235 | int nodeNum() const { return Parent::nodeNum(); } |
| 236 | /// \brief Number of arcs. |
| 237 | int arcNum() const { return Parent::arcNum(); } |
| 238 | |
| 239 | /// \brief Linear combination map. |
| 240 | /// |
| 241 | /// It makes possible to give back a linear combination |
| 242 | /// for each node. This function works like the \c std::accumulate |
| 243 | /// so it accumulates the \c bf binary function with the \c fv |
| 244 | /// first value. The map accumulates only on that dimensions where |
| 245 | /// the node's index is one. The accumulated values should be |
| 246 | /// given by the \c begin and \c end iterators and the length of this |
| 247 | /// range should be equal to the dimension number of the digraph. |
| 248 | /// |
| 249 | ///\code |
| 250 | /// const int DIM = 3; |
| 251 | /// HyperCubeDigraph digraph(DIM); |
| 252 | /// dim2::Point<double> base[DIM]; |
| 253 | /// for (int k = 0; k < DIM; ++k) { |
| 254 | /// base[k].x = rnd(); |
| 255 | /// base[k].y = rnd(); |
| 256 | /// } |
| 257 | /// HyperCubeDigraph::HyperMap<dim2::Point<double> > |
| 258 | /// pos(digraph, base, base + DIM, dim2::Point<double>(0.0, 0.0)); |
| 259 | ///\endcode |
| 260 | /// |
| 261 | /// \see HyperCubeDigraph |
| 262 | template <typename T, typename BF = std::plus<T> > |
| 263 | class HyperMap { |
| 264 | public: |
| 265 | |
| 266 | typedef Node Key; |
| 267 | typedef T Value; |
| 268 | |
| 269 | |
| 270 | /// \brief Constructor for HyperMap. |
| 271 | /// |
| 272 | /// Construct a HyperMap for the given digraph. The accumulated values |
| 273 | /// should be given by the \c begin and \c end iterators and the length |
| 274 | /// of this range should be equal to the dimension number of the digraph. |
| 275 | /// |
| 276 | /// This function accumulates the \c bf binary function with |
| 277 | /// the \c fv first value. The map accumulates only on that dimensions |
| 278 | /// where the node's index is one. |
| 279 | template <typename It> |
| 280 | HyperMap(const Digraph& digraph, It begin, It end, |
| 281 | T fv = 0.0, const BF& bf = BF()) |
| 282 | : _graph(digraph), _values(begin, end), _first_value(fv), _bin_func(bf) |
| 283 | { |
| 284 | LEMON_ASSERT(_values.size() == digraph.dimension(), |
| 285 | "Wrong size of dimension"); |
| 286 | } |
| 287 | |
| 288 | /// \brief Gives back the partial accumulated value. |
| 289 | /// |
| 290 | /// Gives back the partial accumulated value. |
| 291 | Value operator[](Key k) const { |
| 292 | Value val = _first_value; |
| 293 | int id = _graph.index(k); |
| 294 | int n = 0; |
| 295 | while (id != 0) { |
| 296 | if (id & 1) { |
| 297 | val = _bin_func(val, _values[n]); |
| 298 | } |
| 299 | id >>= 1; |
| 300 | ++n; |
| 301 | } |
| 302 | return val; |
| 303 | } |
| 304 | |
| 305 | private: |
| 306 | const Digraph& _graph; |
| 307 | std::vector<T> _values; |
| 308 | T _first_value; |
| 309 | BF _bin_func; |
| 310 | }; |
| 311 | |
| 312 | }; |
| 313 | |
| 314 | } |
| 315 | |
| 316 | #endif |