lemon/concepts/digraph.h
author Peter Kovacs <kpeter@inf.elte.hu>
Thu, 12 Nov 2009 23:26:13 +0100
changeset 806 fa6f37d7a25b
parent 734 bd72f8d20f33
child 877 141f9c0db4a3
permissions -rw-r--r--
Entirely rework CapacityScaling (#180)

- Use the new interface similarly to NetworkSimplex.
- Rework the implementation using an efficient internal structure
for handling the residual network. This improvement made the
code much faster (up to 2-5 times faster on large graphs).
- Handle GEQ supply type (LEQ is not supported).
- Handle negative costs for arcs of finite capacity.
(Note that this algorithm cannot handle arcs of negative cost
and infinite upper bound, thus it returns UNBOUNDED if such
an arc exists.)
- Extend the documentation.
     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_CONCEPTS_DIGRAPH_H
    20 #define LEMON_CONCEPTS_DIGRAPH_H
    21 
    22 ///\ingroup graph_concepts
    23 ///\file
    24 ///\brief The concept of directed graphs.
    25 
    26 #include <lemon/core.h>
    27 #include <lemon/concepts/maps.h>
    28 #include <lemon/concept_check.h>
    29 #include <lemon/concepts/graph_components.h>
    30 
    31 namespace lemon {
    32   namespace concepts {
    33 
    34     /// \ingroup graph_concepts
    35     ///
    36     /// \brief Class describing the concept of directed graphs.
    37     ///
    38     /// This class describes the common interface of all directed
    39     /// graphs (digraphs).
    40     ///
    41     /// Like all concept classes, it only provides an interface
    42     /// without any sensible implementation. So any general algorithm for
    43     /// directed graphs should compile with this class, but it will not
    44     /// run properly, of course.
    45     /// An actual digraph implementation like \ref ListDigraph or
    46     /// \ref SmartDigraph may have additional functionality.
    47     ///
    48     /// \sa Graph
    49     class Digraph {
    50     private:
    51       /// Diraphs are \e not copy constructible. Use DigraphCopy instead.
    52       Digraph(const Digraph &) {}
    53       /// \brief Assignment of a digraph to another one is \e not allowed.
    54       /// Use DigraphCopy instead.
    55       void operator=(const Digraph &) {}
    56 
    57     public:
    58       /// Default constructor.
    59       Digraph() { }
    60 
    61       /// The node type of the digraph
    62 
    63       /// This class identifies a node of the digraph. It also serves
    64       /// as a base class of the node iterators,
    65       /// thus they convert to this type.
    66       class Node {
    67       public:
    68         /// Default constructor
    69 
    70         /// Default constructor.
    71         /// \warning It sets the object to an undefined value.
    72         Node() { }
    73         /// Copy constructor.
    74 
    75         /// Copy constructor.
    76         ///
    77         Node(const Node&) { }
    78 
    79         /// %Invalid constructor \& conversion.
    80 
    81         /// Initializes the object to be invalid.
    82         /// \sa Invalid for more details.
    83         Node(Invalid) { }
    84         /// Equality operator
    85 
    86         /// Equality operator.
    87         ///
    88         /// Two iterators are equal if and only if they point to the
    89         /// same object or both are \c INVALID.
    90         bool operator==(Node) const { return true; }
    91 
    92         /// Inequality operator
    93 
    94         /// Inequality operator.
    95         bool operator!=(Node) const { return true; }
    96 
    97         /// Artificial ordering operator.
    98 
    99         /// Artificial ordering operator.
   100         ///
   101         /// \note This operator only has to define some strict ordering of
   102         /// the nodes; this order has nothing to do with the iteration
   103         /// ordering of the nodes.
   104         bool operator<(Node) const { return false; }
   105       };
   106 
   107       /// Iterator class for the nodes.
   108 
   109       /// This iterator goes through each node of the digraph.
   110       /// Its usage is quite simple, for example, you can count the number
   111       /// of nodes in a digraph \c g of type \c %Digraph like this:
   112       ///\code
   113       /// int count=0;
   114       /// for (Digraph::NodeIt n(g); n!=INVALID; ++n) ++count;
   115       ///\endcode
   116       class NodeIt : public Node {
   117       public:
   118         /// Default constructor
   119 
   120         /// Default constructor.
   121         /// \warning It sets the iterator to an undefined value.
   122         NodeIt() { }
   123         /// Copy constructor.
   124 
   125         /// Copy constructor.
   126         ///
   127         NodeIt(const NodeIt& n) : Node(n) { }
   128         /// %Invalid constructor \& conversion.
   129 
   130         /// Initializes the iterator to be invalid.
   131         /// \sa Invalid for more details.
   132         NodeIt(Invalid) { }
   133         /// Sets the iterator to the first node.
   134 
   135         /// Sets the iterator to the first node of the given digraph.
   136         ///
   137         explicit NodeIt(const Digraph&) { }
   138         /// Sets the iterator to the given node.
   139 
   140         /// Sets the iterator to the given node of the given digraph.
   141         ///
   142         NodeIt(const Digraph&, const Node&) { }
   143         /// Next node.
   144 
   145         /// Assign the iterator to the next node.
   146         ///
   147         NodeIt& operator++() { return *this; }
   148       };
   149 
   150 
   151       /// The arc type of the digraph
   152 
   153       /// This class identifies an arc of the digraph. It also serves
   154       /// as a base class of the arc iterators,
   155       /// thus they will convert to this type.
   156       class Arc {
   157       public:
   158         /// Default constructor
   159 
   160         /// Default constructor.
   161         /// \warning It sets the object to an undefined value.
   162         Arc() { }
   163         /// Copy constructor.
   164 
   165         /// Copy constructor.
   166         ///
   167         Arc(const Arc&) { }
   168         /// %Invalid constructor \& conversion.
   169 
   170         /// Initializes the object to be invalid.
   171         /// \sa Invalid for more details.
   172         Arc(Invalid) { }
   173         /// Equality operator
   174 
   175         /// Equality operator.
   176         ///
   177         /// Two iterators are equal if and only if they point to the
   178         /// same object or both are \c INVALID.
   179         bool operator==(Arc) const { return true; }
   180         /// Inequality operator
   181 
   182         /// Inequality operator.
   183         bool operator!=(Arc) const { return true; }
   184 
   185         /// Artificial ordering operator.
   186 
   187         /// Artificial ordering operator.
   188         ///
   189         /// \note This operator only has to define some strict ordering of
   190         /// the arcs; this order has nothing to do with the iteration
   191         /// ordering of the arcs.
   192         bool operator<(Arc) const { return false; }
   193       };
   194 
   195       /// Iterator class for the outgoing arcs of a node.
   196 
   197       /// This iterator goes trough the \e outgoing arcs of a certain node
   198       /// of a digraph.
   199       /// Its usage is quite simple, for example, you can count the number
   200       /// of outgoing arcs of a node \c n
   201       /// in a digraph \c g of type \c %Digraph as follows.
   202       ///\code
   203       /// int count=0;
   204       /// for (Digraph::OutArcIt a(g, n); a!=INVALID; ++a) ++count;
   205       ///\endcode
   206       class OutArcIt : public Arc {
   207       public:
   208         /// Default constructor
   209 
   210         /// Default constructor.
   211         /// \warning It sets the iterator to an undefined value.
   212         OutArcIt() { }
   213         /// Copy constructor.
   214 
   215         /// Copy constructor.
   216         ///
   217         OutArcIt(const OutArcIt& e) : Arc(e) { }
   218         /// %Invalid constructor \& conversion.
   219 
   220         /// Initializes the iterator to be invalid.
   221         /// \sa Invalid for more details.
   222         OutArcIt(Invalid) { }
   223         /// Sets the iterator to the first outgoing arc.
   224 
   225         /// Sets the iterator to the first outgoing arc of the given node.
   226         ///
   227         OutArcIt(const Digraph&, const Node&) { }
   228         /// Sets the iterator to the given arc.
   229 
   230         /// Sets the iterator to the given arc of the given digraph.
   231         ///
   232         OutArcIt(const Digraph&, const Arc&) { }
   233         /// Next outgoing arc
   234 
   235         /// Assign the iterator to the next
   236         /// outgoing arc of the corresponding node.
   237         OutArcIt& operator++() { return *this; }
   238       };
   239 
   240       /// Iterator class for the incoming arcs of a node.
   241 
   242       /// This iterator goes trough the \e incoming arcs of a certain node
   243       /// of a digraph.
   244       /// Its usage is quite simple, for example, you can count the number
   245       /// of incoming arcs of a node \c n
   246       /// in a digraph \c g of type \c %Digraph as follows.
   247       ///\code
   248       /// int count=0;
   249       /// for(Digraph::InArcIt a(g, n); a!=INVALID; ++a) ++count;
   250       ///\endcode
   251       class InArcIt : public Arc {
   252       public:
   253         /// Default constructor
   254 
   255         /// Default constructor.
   256         /// \warning It sets the iterator to an undefined value.
   257         InArcIt() { }
   258         /// Copy constructor.
   259 
   260         /// Copy constructor.
   261         ///
   262         InArcIt(const InArcIt& e) : Arc(e) { }
   263         /// %Invalid constructor \& conversion.
   264 
   265         /// Initializes the iterator to be invalid.
   266         /// \sa Invalid for more details.
   267         InArcIt(Invalid) { }
   268         /// Sets the iterator to the first incoming arc.
   269 
   270         /// Sets the iterator to the first incoming arc of the given node.
   271         ///
   272         InArcIt(const Digraph&, const Node&) { }
   273         /// Sets the iterator to the given arc.
   274 
   275         /// Sets the iterator to the given arc of the given digraph.
   276         ///
   277         InArcIt(const Digraph&, const Arc&) { }
   278         /// Next incoming arc
   279 
   280         /// Assign the iterator to the next
   281         /// incoming arc of the corresponding node.
   282         InArcIt& operator++() { return *this; }
   283       };
   284 
   285       /// Iterator class for the arcs.
   286 
   287       /// This iterator goes through each arc of the digraph.
   288       /// Its usage is quite simple, for example, you can count the number
   289       /// of arcs in a digraph \c g of type \c %Digraph as follows:
   290       ///\code
   291       /// int count=0;
   292       /// for(Digraph::ArcIt a(g); a!=INVALID; ++a) ++count;
   293       ///\endcode
   294       class ArcIt : public Arc {
   295       public:
   296         /// Default constructor
   297 
   298         /// Default constructor.
   299         /// \warning It sets the iterator to an undefined value.
   300         ArcIt() { }
   301         /// Copy constructor.
   302 
   303         /// Copy constructor.
   304         ///
   305         ArcIt(const ArcIt& e) : Arc(e) { }
   306         /// %Invalid constructor \& conversion.
   307 
   308         /// Initializes the iterator to be invalid.
   309         /// \sa Invalid for more details.
   310         ArcIt(Invalid) { }
   311         /// Sets the iterator to the first arc.
   312 
   313         /// Sets the iterator to the first arc of the given digraph.
   314         ///
   315         explicit ArcIt(const Digraph& g) { ignore_unused_variable_warning(g); }
   316         /// Sets the iterator to the given arc.
   317 
   318         /// Sets the iterator to the given arc of the given digraph.
   319         ///
   320         ArcIt(const Digraph&, const Arc&) { }
   321         /// Next arc
   322 
   323         /// Assign the iterator to the next arc.
   324         ///
   325         ArcIt& operator++() { return *this; }
   326       };
   327 
   328       /// \brief The source node of the arc.
   329       ///
   330       /// Returns the source node of the given arc.
   331       Node source(Arc) const { return INVALID; }
   332 
   333       /// \brief The target node of the arc.
   334       ///
   335       /// Returns the target node of the given arc.
   336       Node target(Arc) const { return INVALID; }
   337 
   338       /// \brief The ID of the node.
   339       ///
   340       /// Returns the ID of the given node.
   341       int id(Node) const { return -1; }
   342 
   343       /// \brief The ID of the arc.
   344       ///
   345       /// Returns the ID of the given arc.
   346       int id(Arc) const { return -1; }
   347 
   348       /// \brief The node with the given ID.
   349       ///
   350       /// Returns the node with the given ID.
   351       /// \pre The argument should be a valid node ID in the digraph.
   352       Node nodeFromId(int) const { return INVALID; }
   353 
   354       /// \brief The arc with the given ID.
   355       ///
   356       /// Returns the arc with the given ID.
   357       /// \pre The argument should be a valid arc ID in the digraph.
   358       Arc arcFromId(int) const { return INVALID; }
   359 
   360       /// \brief An upper bound on the node IDs.
   361       ///
   362       /// Returns an upper bound on the node IDs.
   363       int maxNodeId() const { return -1; }
   364 
   365       /// \brief An upper bound on the arc IDs.
   366       ///
   367       /// Returns an upper bound on the arc IDs.
   368       int maxArcId() const { return -1; }
   369 
   370       void first(Node&) const {}
   371       void next(Node&) const {}
   372 
   373       void first(Arc&) const {}
   374       void next(Arc&) const {}
   375 
   376 
   377       void firstIn(Arc&, const Node&) const {}
   378       void nextIn(Arc&) const {}
   379 
   380       void firstOut(Arc&, const Node&) const {}
   381       void nextOut(Arc&) const {}
   382 
   383       // The second parameter is dummy.
   384       Node fromId(int, Node) const { return INVALID; }
   385       // The second parameter is dummy.
   386       Arc fromId(int, Arc) const { return INVALID; }
   387 
   388       // Dummy parameter.
   389       int maxId(Node) const { return -1; }
   390       // Dummy parameter.
   391       int maxId(Arc) const { return -1; }
   392 
   393       /// \brief The opposite node on the arc.
   394       ///
   395       /// Returns the opposite node on the given arc.
   396       Node oppositeNode(Node, Arc) const { return INVALID; }
   397 
   398       /// \brief The base node of the iterator.
   399       ///
   400       /// Returns the base node of the given outgoing arc iterator
   401       /// (i.e. the source node of the corresponding arc).
   402       Node baseNode(OutArcIt) const { return INVALID; }
   403 
   404       /// \brief The running node of the iterator.
   405       ///
   406       /// Returns the running node of the given outgoing arc iterator
   407       /// (i.e. the target node of the corresponding arc).
   408       Node runningNode(OutArcIt) const { return INVALID; }
   409 
   410       /// \brief The base node of the iterator.
   411       ///
   412       /// Returns the base node of the given incomming arc iterator
   413       /// (i.e. the target node of the corresponding arc).
   414       Node baseNode(InArcIt) const { return INVALID; }
   415 
   416       /// \brief The running node of the iterator.
   417       ///
   418       /// Returns the running node of the given incomming arc iterator
   419       /// (i.e. the source node of the corresponding arc).
   420       Node runningNode(InArcIt) const { return INVALID; }
   421 
   422       /// \brief Standard graph map type for the nodes.
   423       ///
   424       /// Standard graph map type for the nodes.
   425       /// It conforms to the ReferenceMap concept.
   426       template<class T>
   427       class NodeMap : public ReferenceMap<Node, T, T&, const T&> {
   428       public:
   429 
   430         /// Constructor
   431         explicit NodeMap(const Digraph&) { }
   432         /// Constructor with given initial value
   433         NodeMap(const Digraph&, T) { }
   434 
   435       private:
   436         ///Copy constructor
   437         NodeMap(const NodeMap& nm) : 
   438           ReferenceMap<Node, T, T&, const T&>(nm) { }
   439         ///Assignment operator
   440         template <typename CMap>
   441         NodeMap& operator=(const CMap&) {
   442           checkConcept<ReadMap<Node, T>, CMap>();
   443           return *this;
   444         }
   445       };
   446 
   447       /// \brief Standard graph map type for the arcs.
   448       ///
   449       /// Standard graph map type for the arcs.
   450       /// It conforms to the ReferenceMap concept.
   451       template<class T>
   452       class ArcMap : public ReferenceMap<Arc, T, T&, const T&> {
   453       public:
   454 
   455         /// Constructor
   456         explicit ArcMap(const Digraph&) { }
   457         /// Constructor with given initial value
   458         ArcMap(const Digraph&, T) { }
   459 
   460       private:
   461         ///Copy constructor
   462         ArcMap(const ArcMap& em) :
   463           ReferenceMap<Arc, T, T&, const T&>(em) { }
   464         ///Assignment operator
   465         template <typename CMap>
   466         ArcMap& operator=(const CMap&) {
   467           checkConcept<ReadMap<Arc, T>, CMap>();
   468           return *this;
   469         }
   470       };
   471 
   472       template <typename _Digraph>
   473       struct Constraints {
   474         void constraints() {
   475           checkConcept<BaseDigraphComponent, _Digraph>();
   476           checkConcept<IterableDigraphComponent<>, _Digraph>();
   477           checkConcept<IDableDigraphComponent<>, _Digraph>();
   478           checkConcept<MappableDigraphComponent<>, _Digraph>();
   479         }
   480       };
   481 
   482     };
   483 
   484   } //namespace concepts
   485 } //namespace lemon
   486 
   487 
   488 
   489 #endif