lemon/full_graph.h
author Peter Kovacs <kpeter@inf.elte.hu>
Fri, 17 Apr 2009 18:04:36 +0200
changeset 609 e6927fe719e6
parent 360 75cf49ce5390
child 582 7a28e215f715
permissions -rw-r--r--
Support >= and <= constraints in NetworkSimplex (#219, #234)

By default the same inequality constraints are supported as by
Circulation (the GEQ form), but the LEQ form can also be selected
using the problemType() function.

The documentation of the min. cost flow module is reworked and
extended with important notes and explanations about the different
variants of the problem and about the dual solution and optimality
conditions.
     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) 2003-2009
     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 LEMON_FULL_GRAPH_H
    20 #define LEMON_FULL_GRAPH_H
    21 
    22 #include <lemon/core.h>
    23 #include <lemon/bits/graph_extender.h>
    24 
    25 ///\ingroup graphs
    26 ///\file
    27 ///\brief FullGraph and FullDigraph classes.
    28 
    29 namespace lemon {
    30 
    31   class FullDigraphBase {
    32   public:
    33 
    34     typedef FullDigraphBase Graph;
    35 
    36     class Node;
    37     class Arc;
    38 
    39   protected:
    40 
    41     int _node_num;
    42     int _arc_num;
    43 
    44     FullDigraphBase() {}
    45 
    46     void construct(int n) { _node_num = n; _arc_num = n * n; }
    47 
    48   public:
    49 
    50     typedef True NodeNumTag;
    51     typedef True ArcNumTag;
    52 
    53     Node operator()(int ix) const { return Node(ix); }
    54     int index(const Node& node) const { return node._id; }
    55 
    56     Arc arc(const Node& s, const Node& t) const {
    57       return Arc(s._id * _node_num + t._id);
    58     }
    59 
    60     int nodeNum() const { return _node_num; }
    61     int arcNum() const { return _arc_num; }
    62 
    63     int maxNodeId() const { return _node_num - 1; }
    64     int maxArcId() const { return _arc_num - 1; }
    65 
    66     Node source(Arc arc) const { return arc._id / _node_num; }
    67     Node target(Arc arc) const { return arc._id % _node_num; }
    68 
    69     static int id(Node node) { return node._id; }
    70     static int id(Arc arc) { return arc._id; }
    71 
    72     static Node nodeFromId(int id) { return Node(id);}
    73     static Arc arcFromId(int id) { return Arc(id);}
    74 
    75     typedef True FindArcTag;
    76 
    77     Arc findArc(Node s, Node t, Arc prev = INVALID) const {
    78       return prev == INVALID ? arc(s, t) : INVALID;
    79     }
    80 
    81     class Node {
    82       friend class FullDigraphBase;
    83 
    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 FullDigraphBase;
    97 
    98     protected:
    99       int _id;  // _node_num * source + target;
   100 
   101       Arc(int id) : _id(id) {}
   102 
   103     public:
   104       Arc() { }
   105       Arc (Invalid) { _id = -1; }
   106       bool operator==(const Arc arc) const {return _id == arc._id;}
   107       bool operator!=(const Arc arc) const {return _id != arc._id;}
   108       bool operator<(const Arc arc) const {return _id < arc._id;}
   109     };
   110 
   111     void first(Node& node) const {
   112       node._id = _node_num - 1;
   113     }
   114 
   115     static void next(Node& node) {
   116       --node._id;
   117     }
   118 
   119     void first(Arc& arc) const {
   120       arc._id = _arc_num - 1;
   121     }
   122 
   123     static void next(Arc& arc) {
   124       --arc._id;
   125     }
   126 
   127     void firstOut(Arc& arc, const Node& node) const {
   128       arc._id = (node._id + 1) * _node_num - 1;
   129     }
   130 
   131     void nextOut(Arc& arc) const {
   132       if (arc._id % _node_num == 0) arc._id = 0;
   133       --arc._id;
   134     }
   135 
   136     void firstIn(Arc& arc, const Node& node) const {
   137       arc._id = _arc_num + node._id - _node_num;
   138     }
   139 
   140     void nextIn(Arc& arc) const {
   141       arc._id -= _node_num;
   142       if (arc._id < 0) arc._id = -1;
   143     }
   144 
   145   };
   146 
   147   typedef DigraphExtender<FullDigraphBase> ExtendedFullDigraphBase;
   148 
   149   /// \ingroup graphs
   150   ///
   151   /// \brief A full digraph class.
   152   ///
   153   /// This is a simple and fast directed full graph implementation.
   154   /// From each node go arcs to each node (including the source node),
   155   /// therefore the number of the arcs in the digraph is the square of
   156   /// the node number. This digraph type is completely static, so you
   157   /// can neither add nor delete either arcs or nodes, and it needs
   158   /// constant space in memory.
   159   ///
   160   /// This class conforms to the \ref concepts::Digraph "Digraph" concept
   161   /// and it also has an important extra feature that its maps are
   162   /// real \ref concepts::ReferenceMap "reference map"s.
   163   ///
   164   /// The \c FullDigraph and \c FullGraph classes are very similar,
   165   /// but there are two differences. While this class conforms only
   166   /// to the \ref concepts::Digraph "Digraph" concept, the \c FullGraph
   167   /// class conforms to the \ref concepts::Graph "Graph" concept,
   168   /// moreover \c FullGraph does not contain a loop arc for each
   169   /// node as \c FullDigraph does.
   170   ///
   171   /// \sa FullGraph
   172   class FullDigraph : public ExtendedFullDigraphBase {
   173   public:
   174 
   175     typedef ExtendedFullDigraphBase Parent;
   176 
   177     /// \brief Constructor
   178     FullDigraph() { construct(0); }
   179 
   180     /// \brief Constructor
   181     ///
   182     /// Constructor.
   183     /// \param n The number of the nodes.
   184     FullDigraph(int n) { construct(n); }
   185 
   186     /// \brief Resizes the digraph
   187     ///
   188     /// Resizes the digraph. The function will fully destroy and
   189     /// rebuild the digraph. This cause that the maps of the digraph will
   190     /// reallocated automatically and the previous values will be lost.
   191     void resize(int n) {
   192       Parent::notifier(Arc()).clear();
   193       Parent::notifier(Node()).clear();
   194       construct(n);
   195       Parent::notifier(Node()).build();
   196       Parent::notifier(Arc()).build();
   197     }
   198 
   199     /// \brief Returns the node with the given index.
   200     ///
   201     /// Returns the node with the given index. Since it is a static
   202     /// digraph its nodes can be indexed with integers from the range
   203     /// <tt>[0..nodeNum()-1]</tt>.
   204     /// \sa index()
   205     Node operator()(int ix) const { return Parent::operator()(ix); }
   206 
   207     /// \brief Returns the index of the given node.
   208     ///
   209     /// Returns the index of the given node. Since it is a static
   210     /// digraph its nodes can be indexed with integers from the range
   211     /// <tt>[0..nodeNum()-1]</tt>.
   212     /// \sa operator()
   213     int index(const Node& node) const { return Parent::index(node); }
   214 
   215     /// \brief Returns the arc connecting the given nodes.
   216     ///
   217     /// Returns the arc connecting the given nodes.
   218     Arc arc(const Node& u, const Node& v) const {
   219       return Parent::arc(u, v);
   220     }
   221 
   222     /// \brief Number of nodes.
   223     int nodeNum() const { return Parent::nodeNum(); }
   224     /// \brief Number of arcs.
   225     int arcNum() const { return Parent::arcNum(); }
   226   };
   227 
   228 
   229   class FullGraphBase {
   230     int _node_num;
   231     int _edge_num;
   232   public:
   233 
   234     typedef FullGraphBase Graph;
   235 
   236     class Node;
   237     class Arc;
   238     class Edge;
   239 
   240   protected:
   241 
   242     FullGraphBase() {}
   243 
   244     void construct(int n) { _node_num = n; _edge_num = n * (n - 1) / 2; }
   245 
   246     int _uid(int e) const {
   247       int u = e / _node_num;
   248       int v = e % _node_num;
   249       return u < v ? u : _node_num - 2 - u;
   250     }
   251 
   252     int _vid(int e) const {
   253       int u = e / _node_num;
   254       int v = e % _node_num;
   255       return u < v ? v : _node_num - 1 - v;
   256     }
   257 
   258     void _uvid(int e, int& u, int& v) const {
   259       u = e / _node_num;
   260       v = e % _node_num;
   261       if  (u >= v) {
   262         u = _node_num - 2 - u;
   263         v = _node_num - 1 - v;
   264       }
   265     }
   266 
   267     void _stid(int a, int& s, int& t) const {
   268       if ((a & 1) == 1) {
   269         _uvid(a >> 1, s, t);
   270       } else {
   271         _uvid(a >> 1, t, s);
   272       }
   273     }
   274 
   275     int _eid(int u, int v) const {
   276       if (u < (_node_num - 1) / 2) {
   277         return u * _node_num + v;
   278       } else {
   279         return (_node_num - 1 - u) * _node_num - v - 1;
   280       }
   281     }
   282 
   283   public:
   284 
   285     Node operator()(int ix) const { return Node(ix); }
   286     int index(const Node& node) const { return node._id; }
   287 
   288     Edge edge(const Node& u, const Node& v) const {
   289       if (u._id < v._id) {
   290         return Edge(_eid(u._id, v._id));
   291       } else if (u._id != v._id) {
   292         return Edge(_eid(v._id, u._id));
   293       } else {
   294         return INVALID;
   295       }
   296     }
   297 
   298     Arc arc(const Node& s, const Node& t) const {
   299       if (s._id < t._id) {
   300         return Arc((_eid(s._id, t._id) << 1) | 1);
   301       } else if (s._id != t._id) {
   302         return Arc(_eid(t._id, s._id) << 1);
   303       } else {
   304         return INVALID;
   305       }
   306     }
   307 
   308     typedef True NodeNumTag;
   309     typedef True ArcNumTag;
   310     typedef True EdgeNumTag;
   311 
   312     int nodeNum() const { return _node_num; }
   313     int arcNum() const { return 2 * _edge_num; }
   314     int edgeNum() const { return _edge_num; }
   315 
   316     static int id(Node node) { return node._id; }
   317     static int id(Arc arc) { return arc._id; }
   318     static int id(Edge edge) { return edge._id; }
   319 
   320     int maxNodeId() const { return _node_num-1; }
   321     int maxArcId() const { return 2 * _edge_num-1; }
   322     int maxEdgeId() const { return _edge_num-1; }
   323 
   324     static Node nodeFromId(int id) { return Node(id);}
   325     static Arc arcFromId(int id) { return Arc(id);}
   326     static Edge edgeFromId(int id) { return Edge(id);}
   327 
   328     Node u(Edge edge) const {
   329       return Node(_uid(edge._id));
   330     }
   331 
   332     Node v(Edge edge) const {
   333       return Node(_vid(edge._id));
   334     }
   335 
   336     Node source(Arc arc) const {
   337       return Node((arc._id & 1) == 1 ?
   338                   _uid(arc._id >> 1) : _vid(arc._id >> 1));
   339     }
   340 
   341     Node target(Arc arc) const {
   342       return Node((arc._id & 1) == 1 ?
   343                   _vid(arc._id >> 1) : _uid(arc._id >> 1));
   344     }
   345 
   346     typedef True FindEdgeTag;
   347     typedef True FindArcTag;
   348 
   349     Edge findEdge(Node u, Node v, Edge prev = INVALID) const {
   350       return prev != INVALID ? INVALID : edge(u, v);
   351     }
   352 
   353     Arc findArc(Node s, Node t, Arc prev = INVALID) const {
   354       return prev != INVALID ? INVALID : arc(s, t);
   355     }
   356 
   357     class Node {
   358       friend class FullGraphBase;
   359 
   360     protected:
   361       int _id;
   362       Node(int id) : _id(id) {}
   363     public:
   364       Node() {}
   365       Node (Invalid) { _id = -1; }
   366       bool operator==(const Node node) const {return _id == node._id;}
   367       bool operator!=(const Node node) const {return _id != node._id;}
   368       bool operator<(const Node node) const {return _id < node._id;}
   369     };
   370 
   371     class Edge {
   372       friend class FullGraphBase;
   373       friend class Arc;
   374 
   375     protected:
   376       int _id;
   377 
   378       Edge(int id) : _id(id) {}
   379 
   380     public:
   381       Edge() { }
   382       Edge (Invalid) { _id = -1; }
   383 
   384       bool operator==(const Edge edge) const {return _id == edge._id;}
   385       bool operator!=(const Edge edge) const {return _id != edge._id;}
   386       bool operator<(const Edge edge) const {return _id < edge._id;}
   387     };
   388 
   389     class Arc {
   390       friend class FullGraphBase;
   391 
   392     protected:
   393       int _id;
   394 
   395       Arc(int id) : _id(id) {}
   396 
   397     public:
   398       Arc() { }
   399       Arc (Invalid) { _id = -1; }
   400 
   401       operator Edge() const { return Edge(_id != -1 ? (_id >> 1) : -1); }
   402 
   403       bool operator==(const Arc arc) const {return _id == arc._id;}
   404       bool operator!=(const Arc arc) const {return _id != arc._id;}
   405       bool operator<(const Arc arc) const {return _id < arc._id;}
   406     };
   407 
   408     static bool direction(Arc arc) {
   409       return (arc._id & 1) == 1;
   410     }
   411 
   412     static Arc direct(Edge edge, bool dir) {
   413       return Arc((edge._id << 1) | (dir ? 1 : 0));
   414     }
   415 
   416     void first(Node& node) const {
   417       node._id = _node_num - 1;
   418     }
   419 
   420     static void next(Node& node) {
   421       --node._id;
   422     }
   423 
   424     void first(Arc& arc) const {
   425       arc._id = (_edge_num << 1) - 1;
   426     }
   427 
   428     static void next(Arc& arc) {
   429       --arc._id;
   430     }
   431 
   432     void first(Edge& edge) const {
   433       edge._id = _edge_num - 1;
   434     }
   435 
   436     static void next(Edge& edge) {
   437       --edge._id;
   438     }
   439 
   440     void firstOut(Arc& arc, const Node& node) const {
   441       int s = node._id, t = _node_num - 1;
   442       if (s < t) {
   443         arc._id = (_eid(s, t) << 1) | 1;
   444       } else {
   445         --t;
   446         arc._id = (t != -1 ? (_eid(t, s) << 1) : -1);
   447       }
   448     }
   449 
   450     void nextOut(Arc& arc) const {
   451       int s, t;
   452       _stid(arc._id, s, t);
   453       --t;
   454       if (s < t) {
   455         arc._id = (_eid(s, t) << 1) | 1;
   456       } else {
   457         if (s == t) --t;
   458         arc._id = (t != -1 ? (_eid(t, s) << 1) : -1);
   459       }
   460     }
   461 
   462     void firstIn(Arc& arc, const Node& node) const {
   463       int s = _node_num - 1, t = node._id;
   464       if (s > t) {
   465         arc._id = (_eid(t, s) << 1);
   466       } else {
   467         --s;
   468         arc._id = (s != -1 ? (_eid(s, t) << 1) | 1 : -1);
   469       }
   470     }
   471 
   472     void nextIn(Arc& arc) const {
   473       int s, t;
   474       _stid(arc._id, s, t);
   475       --s;
   476       if (s > t) {
   477         arc._id = (_eid(t, s) << 1);
   478       } else {
   479         if (s == t) --s;
   480         arc._id = (s != -1 ? (_eid(s, t) << 1) | 1 : -1);
   481       }
   482     }
   483 
   484     void firstInc(Edge& edge, bool& dir, const Node& node) const {
   485       int u = node._id, v = _node_num - 1;
   486       if (u < v) {
   487         edge._id = _eid(u, v);
   488         dir = true;
   489       } else {
   490         --v;
   491         edge._id = (v != -1 ? _eid(v, u) : -1);
   492         dir = false;
   493       }
   494     }
   495 
   496     void nextInc(Edge& edge, bool& dir) const {
   497       int u, v;
   498       if (dir) {
   499         _uvid(edge._id, u, v);
   500         --v;
   501         if (u < v) {
   502           edge._id = _eid(u, v);
   503         } else {
   504           --v;
   505           edge._id = (v != -1 ? _eid(v, u) : -1);
   506           dir = false;
   507         }
   508       } else {
   509         _uvid(edge._id, v, u);
   510         --v;
   511         edge._id = (v != -1 ? _eid(v, u) : -1);
   512       }
   513     }
   514 
   515   };
   516 
   517   typedef GraphExtender<FullGraphBase> ExtendedFullGraphBase;
   518 
   519   /// \ingroup graphs
   520   ///
   521   /// \brief An undirected full graph class.
   522   ///
   523   /// This is a simple and fast undirected full graph
   524   /// implementation. From each node go edge to each other node,
   525   /// therefore the number of edges in the graph is \f$n(n-1)/2\f$.
   526   /// This graph type is completely static, so you can neither
   527   /// add nor delete either edges or nodes, and it needs constant
   528   /// space in memory.
   529   ///
   530   /// This class conforms to the \ref concepts::Graph "Graph" concept
   531   /// and it also has an important extra feature that its maps are
   532   /// real \ref concepts::ReferenceMap "reference map"s.
   533   ///
   534   /// The \c FullGraph and \c FullDigraph classes are very similar,
   535   /// but there are two differences. While the \c FullDigraph class
   536   /// conforms only to the \ref concepts::Digraph "Digraph" concept,
   537   /// this class conforms to the \ref concepts::Graph "Graph" concept,
   538   /// moreover \c FullGraph does not contain a loop arc for each
   539   /// node as \c FullDigraph does.
   540   ///
   541   /// \sa FullDigraph
   542   class FullGraph : public ExtendedFullGraphBase {
   543   public:
   544 
   545     typedef ExtendedFullGraphBase Parent;
   546 
   547     /// \brief Constructor
   548     FullGraph() { construct(0); }
   549 
   550     /// \brief Constructor
   551     ///
   552     /// Constructor.
   553     /// \param n The number of the nodes.
   554     FullGraph(int n) { construct(n); }
   555 
   556     /// \brief Resizes the graph
   557     ///
   558     /// Resizes the graph. The function will fully destroy and
   559     /// rebuild the graph. This cause that the maps of the graph will
   560     /// reallocated automatically and the previous values will be lost.
   561     void resize(int n) {
   562       Parent::notifier(Arc()).clear();
   563       Parent::notifier(Edge()).clear();
   564       Parent::notifier(Node()).clear();
   565       construct(n);
   566       Parent::notifier(Node()).build();
   567       Parent::notifier(Edge()).build();
   568       Parent::notifier(Arc()).build();
   569     }
   570 
   571     /// \brief Returns the node with the given index.
   572     ///
   573     /// Returns the node with the given index. Since it is a static
   574     /// graph its nodes can be indexed with integers from the range
   575     /// <tt>[0..nodeNum()-1]</tt>.
   576     /// \sa index()
   577     Node operator()(int ix) const { return Parent::operator()(ix); }
   578 
   579     /// \brief Returns the index of the given node.
   580     ///
   581     /// Returns the index of the given node. Since it is a static
   582     /// graph its nodes can be indexed with integers from the range
   583     /// <tt>[0..nodeNum()-1]</tt>.
   584     /// \sa operator()
   585     int index(const Node& node) const { return Parent::index(node); }
   586 
   587     /// \brief Returns the arc connecting the given nodes.
   588     ///
   589     /// Returns the arc connecting the given nodes.
   590     Arc arc(const Node& s, const Node& t) const {
   591       return Parent::arc(s, t);
   592     }
   593 
   594     /// \brief Returns the edge connects the given nodes.
   595     ///
   596     /// Returns the edge connects the given nodes.
   597     Edge edge(const Node& u, const Node& v) const {
   598       return Parent::edge(u, v);
   599     }
   600 
   601     /// \brief Number of nodes.
   602     int nodeNum() const { return Parent::nodeNum(); }
   603     /// \brief Number of arcs.
   604     int arcNum() const { return Parent::arcNum(); }
   605     /// \brief Number of edges.
   606     int edgeNum() const { return Parent::edgeNum(); }
   607 
   608   };
   609 
   610 
   611 } //namespace lemon
   612 
   613 
   614 #endif //LEMON_FULL_GRAPH_H