lemon/concepts/digraph.h
changeset 782 ceb2756dea2a
parent 580 2313edd0db0b
child 786 e20173729589
     1.1 --- a/lemon/concepts/digraph.h	Mon Sep 28 15:53:20 2009 +0200
     1.2 +++ b/lemon/concepts/digraph.h	Thu Nov 05 10:27:17 2009 +0100
     1.3 @@ -35,46 +35,40 @@
     1.4      ///
     1.5      /// \brief Class describing the concept of directed graphs.
     1.6      ///
     1.7 -    /// This class describes the \ref concept "concept" of the
     1.8 -    /// immutable directed digraphs.
     1.9 +    /// This class describes the common interface of all directed
    1.10 +    /// graphs (digraphs).
    1.11      ///
    1.12 -    /// Note that actual digraph implementation like @ref ListDigraph or
    1.13 -    /// @ref SmartDigraph may have several additional functionality.
    1.14 +    /// Like all concept classes, it only provides an interface
    1.15 +    /// without any sensible implementation. So any general algorithm for
    1.16 +    /// directed graphs should compile with this class, but it will not
    1.17 +    /// run properly, of course.
    1.18 +    /// An actual digraph implementation like \ref ListDigraph or
    1.19 +    /// \ref SmartDigraph may have additional functionality.
    1.20      ///
    1.21 -    /// \sa concept
    1.22 +    /// \sa Graph
    1.23      class Digraph {
    1.24      private:
    1.25 -      ///Digraphs are \e not copy constructible. Use DigraphCopy() instead.
    1.26 +      /// Diraphs are \e not copy constructible. Use DigraphCopy instead.
    1.27 +      Digraph(const Digraph &) {}
    1.28 +      /// \brief Assignment of a digraph to another one is \e not allowed.
    1.29 +      /// Use DigraphCopy instead.
    1.30 +      void operator=(const Digraph &) {}
    1.31  
    1.32 -      ///Digraphs are \e not copy constructible. Use DigraphCopy() instead.
    1.33 -      ///
    1.34 -      Digraph(const Digraph &) {};
    1.35 -      ///\brief Assignment of \ref Digraph "Digraph"s to another ones are
    1.36 -      ///\e not allowed. Use DigraphCopy() instead.
    1.37 +    public:
    1.38 +      /// Default constructor.
    1.39 +      Digraph() { }
    1.40  
    1.41 -      ///Assignment of \ref Digraph "Digraph"s to another ones are
    1.42 -      ///\e not allowed.  Use DigraphCopy() instead.
    1.43 -
    1.44 -      void operator=(const Digraph &) {}
    1.45 -    public:
    1.46 -      ///\e
    1.47 -
    1.48 -      /// Defalult constructor.
    1.49 -
    1.50 -      /// Defalult constructor.
    1.51 -      ///
    1.52 -      Digraph() { }
    1.53 -      /// Class for identifying a node of the digraph
    1.54 +      /// The node type of the digraph
    1.55  
    1.56        /// This class identifies a node of the digraph. It also serves
    1.57        /// as a base class of the node iterators,
    1.58 -      /// thus they will convert to this type.
    1.59 +      /// thus they convert to this type.
    1.60        class Node {
    1.61        public:
    1.62          /// Default constructor
    1.63  
    1.64 -        /// @warning The default constructor sets the iterator
    1.65 -        /// to an undefined value.
    1.66 +        /// Default constructor.
    1.67 +        /// \warning It sets the object to an undefined value.
    1.68          Node() { }
    1.69          /// Copy constructor.
    1.70  
    1.71 @@ -82,40 +76,39 @@
    1.72          ///
    1.73          Node(const Node&) { }
    1.74  
    1.75 -        /// Invalid constructor \& conversion.
    1.76 +        /// %Invalid constructor \& conversion.
    1.77  
    1.78 -        /// This constructor initializes the iterator to be invalid.
    1.79 +        /// Initializes the object to be invalid.
    1.80          /// \sa Invalid for more details.
    1.81          Node(Invalid) { }
    1.82          /// Equality operator
    1.83  
    1.84 +        /// Equality operator.
    1.85 +        ///
    1.86          /// Two iterators are equal if and only if they point to the
    1.87 -        /// same object or both are invalid.
    1.88 +        /// same object or both are \c INVALID.
    1.89          bool operator==(Node) const { return true; }
    1.90  
    1.91          /// Inequality operator
    1.92  
    1.93 -        /// \sa operator==(Node n)
    1.94 -        ///
    1.95 +        /// Inequality operator.
    1.96          bool operator!=(Node) const { return true; }
    1.97  
    1.98          /// Artificial ordering operator.
    1.99  
   1.100 -        /// To allow the use of digraph descriptors as key type in std::map or
   1.101 -        /// similar associative container we require this.
   1.102 +        /// Artificial ordering operator.
   1.103          ///
   1.104 -        /// \note This operator only have to define some strict ordering of
   1.105 -        /// the items; this order has nothing to do with the iteration
   1.106 -        /// ordering of the items.
   1.107 +        /// \note This operator only has to define some strict ordering of
   1.108 +        /// the nodes; this order has nothing to do with the iteration
   1.109 +        /// ordering of the nodes.
   1.110          bool operator<(Node) const { return false; }
   1.111 -
   1.112        };
   1.113  
   1.114 -      /// This iterator goes through each node.
   1.115 +      /// Iterator class for the nodes.
   1.116  
   1.117 -      /// This iterator goes through each node.
   1.118 +      /// This iterator goes through each node of the digraph.
   1.119        /// Its usage is quite simple, for example you can count the number
   1.120 -      /// of nodes in digraph \c g of type \c Digraph like this:
   1.121 +      /// of nodes in a digraph \c g of type \c %Digraph like this:
   1.122        ///\code
   1.123        /// int count=0;
   1.124        /// for (Digraph::NodeIt n(g); n!=INVALID; ++n) ++count;
   1.125 @@ -124,30 +117,28 @@
   1.126        public:
   1.127          /// Default constructor
   1.128  
   1.129 -        /// @warning The default constructor sets the iterator
   1.130 -        /// to an undefined value.
   1.131 +        /// Default constructor.
   1.132 +        /// \warning It sets the iterator to an undefined value.
   1.133          NodeIt() { }
   1.134          /// Copy constructor.
   1.135  
   1.136          /// Copy constructor.
   1.137          ///
   1.138          NodeIt(const NodeIt& n) : Node(n) { }
   1.139 -        /// Invalid constructor \& conversion.
   1.140 +        /// %Invalid constructor \& conversion.
   1.141  
   1.142 -        /// Initialize the iterator to be invalid.
   1.143 +        /// Initializes the iterator to be invalid.
   1.144          /// \sa Invalid for more details.
   1.145          NodeIt(Invalid) { }
   1.146          /// Sets the iterator to the first node.
   1.147  
   1.148 -        /// Sets the iterator to the first node of \c g.
   1.149 +        /// Sets the iterator to the first node of the given digraph.
   1.150          ///
   1.151 -        NodeIt(const Digraph&) { }
   1.152 -        /// Node -> NodeIt conversion.
   1.153 +        explicit NodeIt(const Digraph&) { }
   1.154 +        /// Sets the iterator to the given node.
   1.155  
   1.156 -        /// Sets the iterator to the node of \c the digraph pointed by
   1.157 -        /// the trivial iterator.
   1.158 -        /// This feature necessitates that each time we
   1.159 -        /// iterate the arc-set, the iteration order is the same.
   1.160 +        /// Sets the iterator to the given node of the given digraph.
   1.161 +        ///
   1.162          NodeIt(const Digraph&, const Node&) { }
   1.163          /// Next node.
   1.164  
   1.165 @@ -157,7 +148,7 @@
   1.166        };
   1.167  
   1.168  
   1.169 -      /// Class for identifying an arc of the digraph
   1.170 +      /// The arc type of the digraph
   1.171  
   1.172        /// This class identifies an arc of the digraph. It also serves
   1.173        /// as a base class of the arc iterators,
   1.174 @@ -166,207 +157,214 @@
   1.175        public:
   1.176          /// Default constructor
   1.177  
   1.178 -        /// @warning The default constructor sets the iterator
   1.179 -        /// to an undefined value.
   1.180 +        /// Default constructor.
   1.181 +        /// \warning It sets the object to an undefined value.
   1.182          Arc() { }
   1.183          /// Copy constructor.
   1.184  
   1.185          /// Copy constructor.
   1.186          ///
   1.187          Arc(const Arc&) { }
   1.188 -        /// Initialize the iterator to be invalid.
   1.189 +        /// %Invalid constructor \& conversion.
   1.190  
   1.191 -        /// Initialize the iterator to be invalid.
   1.192 -        ///
   1.193 +        /// Initializes the object to be invalid.
   1.194 +        /// \sa Invalid for more details.
   1.195          Arc(Invalid) { }
   1.196          /// Equality operator
   1.197  
   1.198 +        /// Equality operator.
   1.199 +        ///
   1.200          /// Two iterators are equal if and only if they point to the
   1.201 -        /// same object or both are invalid.
   1.202 +        /// same object or both are \c INVALID.
   1.203          bool operator==(Arc) const { return true; }
   1.204          /// Inequality operator
   1.205  
   1.206 -        /// \sa operator==(Arc n)
   1.207 -        ///
   1.208 +        /// Inequality operator.
   1.209          bool operator!=(Arc) const { return true; }
   1.210  
   1.211          /// Artificial ordering operator.
   1.212  
   1.213 -        /// To allow the use of digraph descriptors as key type in std::map or
   1.214 -        /// similar associative container we require this.
   1.215 +        /// Artificial ordering operator.
   1.216          ///
   1.217 -        /// \note This operator only have to define some strict ordering of
   1.218 -        /// the items; this order has nothing to do with the iteration
   1.219 -        /// ordering of the items.
   1.220 +        /// \note This operator only has to define some strict ordering of
   1.221 +        /// the arcs; this order has nothing to do with the iteration
   1.222 +        /// ordering of the arcs.
   1.223          bool operator<(Arc) const { return false; }
   1.224        };
   1.225  
   1.226 -      /// This iterator goes trough the outgoing arcs of a node.
   1.227 +      /// Iterator class for the outgoing arcs of a node.
   1.228  
   1.229        /// This iterator goes trough the \e outgoing arcs of a certain node
   1.230        /// of a digraph.
   1.231        /// Its usage is quite simple, for example you can count the number
   1.232        /// of outgoing arcs of a node \c n
   1.233 -      /// in digraph \c g of type \c Digraph as follows.
   1.234 +      /// in a digraph \c g of type \c %Digraph as follows.
   1.235        ///\code
   1.236        /// int count=0;
   1.237 -      /// for (Digraph::OutArcIt e(g, n); e!=INVALID; ++e) ++count;
   1.238 +      /// for (Digraph::OutArcIt a(g, n); a!=INVALID; ++a) ++count;
   1.239        ///\endcode
   1.240 -
   1.241        class OutArcIt : public Arc {
   1.242        public:
   1.243          /// Default constructor
   1.244  
   1.245 -        /// @warning The default constructor sets the iterator
   1.246 -        /// to an undefined value.
   1.247 +        /// Default constructor.
   1.248 +        /// \warning It sets the iterator to an undefined value.
   1.249          OutArcIt() { }
   1.250          /// Copy constructor.
   1.251  
   1.252          /// Copy constructor.
   1.253          ///
   1.254          OutArcIt(const OutArcIt& e) : Arc(e) { }
   1.255 -        /// Initialize the iterator to be invalid.
   1.256 +        /// %Invalid constructor \& conversion.
   1.257  
   1.258 -        /// Initialize the iterator to be invalid.
   1.259 +        /// Initializes the iterator to be invalid.
   1.260 +        /// \sa Invalid for more details.
   1.261 +        OutArcIt(Invalid) { }
   1.262 +        /// Sets the iterator to the first outgoing arc.
   1.263 +
   1.264 +        /// Sets the iterator to the first outgoing arc of the given node.
   1.265          ///
   1.266 -        OutArcIt(Invalid) { }
   1.267 -        /// This constructor sets the iterator to the first outgoing arc.
   1.268 +        OutArcIt(const Digraph&, const Node&) { }
   1.269 +        /// Sets the iterator to the given arc.
   1.270  
   1.271 -        /// This constructor sets the iterator to the first outgoing arc of
   1.272 -        /// the node.
   1.273 -        OutArcIt(const Digraph&, const Node&) { }
   1.274 -        /// Arc -> OutArcIt conversion
   1.275 -
   1.276 -        /// Sets the iterator to the value of the trivial iterator.
   1.277 -        /// This feature necessitates that each time we
   1.278 -        /// iterate the arc-set, the iteration order is the same.
   1.279 +        /// Sets the iterator to the given arc of the given digraph.
   1.280 +        ///
   1.281          OutArcIt(const Digraph&, const Arc&) { }
   1.282 -        ///Next outgoing arc
   1.283 +        /// Next outgoing arc
   1.284  
   1.285          /// Assign the iterator to the next
   1.286          /// outgoing arc of the corresponding node.
   1.287          OutArcIt& operator++() { return *this; }
   1.288        };
   1.289  
   1.290 -      /// This iterator goes trough the incoming arcs of a node.
   1.291 +      /// Iterator class for the incoming arcs of a node.
   1.292  
   1.293        /// This iterator goes trough the \e incoming arcs of a certain node
   1.294        /// of a digraph.
   1.295        /// Its usage is quite simple, for example you can count the number
   1.296 -      /// of outgoing arcs of a node \c n
   1.297 -      /// in digraph \c g of type \c Digraph as follows.
   1.298 +      /// of incoming arcs of a node \c n
   1.299 +      /// in a digraph \c g of type \c %Digraph as follows.
   1.300        ///\code
   1.301        /// int count=0;
   1.302 -      /// for(Digraph::InArcIt e(g, n); e!=INVALID; ++e) ++count;
   1.303 +      /// for(Digraph::InArcIt a(g, n); a!=INVALID; ++a) ++count;
   1.304        ///\endcode
   1.305 -
   1.306        class InArcIt : public Arc {
   1.307        public:
   1.308          /// Default constructor
   1.309  
   1.310 -        /// @warning The default constructor sets the iterator
   1.311 -        /// to an undefined value.
   1.312 +        /// Default constructor.
   1.313 +        /// \warning It sets the iterator to an undefined value.
   1.314          InArcIt() { }
   1.315          /// Copy constructor.
   1.316  
   1.317          /// Copy constructor.
   1.318          ///
   1.319          InArcIt(const InArcIt& e) : Arc(e) { }
   1.320 -        /// Initialize the iterator to be invalid.
   1.321 +        /// %Invalid constructor \& conversion.
   1.322  
   1.323 -        /// Initialize the iterator to be invalid.
   1.324 +        /// Initializes the iterator to be invalid.
   1.325 +        /// \sa Invalid for more details.
   1.326 +        InArcIt(Invalid) { }
   1.327 +        /// Sets the iterator to the first incoming arc.
   1.328 +
   1.329 +        /// Sets the iterator to the first incoming arc of the given node.
   1.330          ///
   1.331 -        InArcIt(Invalid) { }
   1.332 -        /// This constructor sets the iterator to first incoming arc.
   1.333 +        InArcIt(const Digraph&, const Node&) { }
   1.334 +        /// Sets the iterator to the given arc.
   1.335  
   1.336 -        /// This constructor set the iterator to the first incoming arc of
   1.337 -        /// the node.
   1.338 -        InArcIt(const Digraph&, const Node&) { }
   1.339 -        /// Arc -> InArcIt conversion
   1.340 -
   1.341 -        /// Sets the iterator to the value of the trivial iterator \c e.
   1.342 -        /// This feature necessitates that each time we
   1.343 -        /// iterate the arc-set, the iteration order is the same.
   1.344 +        /// Sets the iterator to the given arc of the given digraph.
   1.345 +        ///
   1.346          InArcIt(const Digraph&, const Arc&) { }
   1.347          /// Next incoming arc
   1.348  
   1.349 -        /// Assign the iterator to the next inarc of the corresponding node.
   1.350 -        ///
   1.351 +        /// Assign the iterator to the next
   1.352 +        /// incoming arc of the corresponding node.
   1.353          InArcIt& operator++() { return *this; }
   1.354        };
   1.355 -      /// This iterator goes through each arc.
   1.356  
   1.357 -      /// This iterator goes through each arc of a digraph.
   1.358 +      /// Iterator class for the arcs.
   1.359 +
   1.360 +      /// This iterator goes through each arc of the digraph.
   1.361        /// Its usage is quite simple, for example you can count the number
   1.362 -      /// of arcs in a digraph \c g of type \c Digraph as follows:
   1.363 +      /// of arcs in a digraph \c g of type \c %Digraph as follows:
   1.364        ///\code
   1.365        /// int count=0;
   1.366 -      /// for(Digraph::ArcIt e(g); e!=INVALID; ++e) ++count;
   1.367 +      /// for(Digraph::ArcIt a(g); a!=INVALID; ++a) ++count;
   1.368        ///\endcode
   1.369        class ArcIt : public Arc {
   1.370        public:
   1.371          /// Default constructor
   1.372  
   1.373 -        /// @warning The default constructor sets the iterator
   1.374 -        /// to an undefined value.
   1.375 +        /// Default constructor.
   1.376 +        /// \warning It sets the iterator to an undefined value.
   1.377          ArcIt() { }
   1.378          /// Copy constructor.
   1.379  
   1.380          /// Copy constructor.
   1.381          ///
   1.382          ArcIt(const ArcIt& e) : Arc(e) { }
   1.383 -        /// Initialize the iterator to be invalid.
   1.384 +        /// %Invalid constructor \& conversion.
   1.385  
   1.386 -        /// Initialize the iterator to be invalid.
   1.387 +        /// Initializes the iterator to be invalid.
   1.388 +        /// \sa Invalid for more details.
   1.389 +        ArcIt(Invalid) { }
   1.390 +        /// Sets the iterator to the first arc.
   1.391 +
   1.392 +        /// Sets the iterator to the first arc of the given digraph.
   1.393          ///
   1.394 -        ArcIt(Invalid) { }
   1.395 -        /// This constructor sets the iterator to the first arc.
   1.396 +        explicit ArcIt(const Digraph& g) { ignore_unused_variable_warning(g); }
   1.397 +        /// Sets the iterator to the given arc.
   1.398  
   1.399 -        /// This constructor sets the iterator to the first arc of \c g.
   1.400 -        ///@param g the digraph
   1.401 -        ArcIt(const Digraph& g) { ignore_unused_variable_warning(g); }
   1.402 -        /// Arc -> ArcIt conversion
   1.403 -
   1.404 -        /// Sets the iterator to the value of the trivial iterator \c e.
   1.405 -        /// This feature necessitates that each time we
   1.406 -        /// iterate the arc-set, the iteration order is the same.
   1.407 +        /// Sets the iterator to the given arc of the given digraph.
   1.408 +        ///
   1.409          ArcIt(const Digraph&, const Arc&) { }
   1.410 -        ///Next arc
   1.411 +        /// Next arc
   1.412  
   1.413          /// Assign the iterator to the next arc.
   1.414 +        ///
   1.415          ArcIt& operator++() { return *this; }
   1.416        };
   1.417 -      ///Gives back the target node of an arc.
   1.418  
   1.419 -      ///Gives back the target node of an arc.
   1.420 +      /// \brief The source node of the arc.
   1.421        ///
   1.422 -      Node target(Arc) const { return INVALID; }
   1.423 -      ///Gives back the source node of an arc.
   1.424 -
   1.425 -      ///Gives back the source node of an arc.
   1.426 -      ///
   1.427 +      /// Returns the source node of the given arc.
   1.428        Node source(Arc) const { return INVALID; }
   1.429  
   1.430 -      /// \brief Returns the ID of the node.
   1.431 +      /// \brief The target node of the arc.
   1.432 +      ///
   1.433 +      /// Returns the target node of the given arc.
   1.434 +      Node target(Arc) const { return INVALID; }
   1.435 +
   1.436 +      /// \brief The ID of the node.
   1.437 +      ///
   1.438 +      /// Returns the ID of the given node.
   1.439        int id(Node) const { return -1; }
   1.440  
   1.441 -      /// \brief Returns the ID of the arc.
   1.442 +      /// \brief The ID of the arc.
   1.443 +      ///
   1.444 +      /// Returns the ID of the given arc.
   1.445        int id(Arc) const { return -1; }
   1.446  
   1.447 -      /// \brief Returns the node with the given ID.
   1.448 +      /// \brief The node with the given ID.
   1.449        ///
   1.450 -      /// \pre The argument should be a valid node ID in the graph.
   1.451 +      /// Returns the node with the given ID.
   1.452 +      /// \pre The argument should be a valid node ID in the digraph.
   1.453        Node nodeFromId(int) const { return INVALID; }
   1.454  
   1.455 -      /// \brief Returns the arc with the given ID.
   1.456 +      /// \brief The arc with the given ID.
   1.457        ///
   1.458 -      /// \pre The argument should be a valid arc ID in the graph.
   1.459 +      /// Returns the arc with the given ID.
   1.460 +      /// \pre The argument should be a valid arc ID in the digraph.
   1.461        Arc arcFromId(int) const { return INVALID; }
   1.462  
   1.463 -      /// \brief Returns an upper bound on the node IDs.
   1.464 +      /// \brief An upper bound on the node IDs.
   1.465 +      ///
   1.466 +      /// Returns an upper bound on the node IDs.
   1.467        int maxNodeId() const { return -1; }
   1.468  
   1.469 -      /// \brief Returns an upper bound on the arc IDs.
   1.470 +      /// \brief An upper bound on the arc IDs.
   1.471 +      ///
   1.472 +      /// Returns an upper bound on the arc IDs.
   1.473        int maxArcId() const { return -1; }
   1.474  
   1.475        void first(Node&) const {}
   1.476 @@ -392,45 +390,46 @@
   1.477        // Dummy parameter.
   1.478        int maxId(Arc) const { return -1; }
   1.479  
   1.480 +      /// \brief The opposite node on the arc.
   1.481 +      ///
   1.482 +      /// Returns the opposite node on the given arc.
   1.483 +      Node oppositeNode(Node, Arc) const { return INVALID; }
   1.484 +
   1.485        /// \brief The base node of the iterator.
   1.486        ///
   1.487 -      /// Gives back the base node of the iterator.
   1.488 -      /// It is always the target of the pointed arc.
   1.489 -      Node baseNode(const InArcIt&) const { return INVALID; }
   1.490 +      /// Returns the base node of the given outgoing arc iterator
   1.491 +      /// (i.e. the source node of the corresponding arc).
   1.492 +      Node baseNode(OutArcIt) const { return INVALID; }
   1.493  
   1.494        /// \brief The running node of the iterator.
   1.495        ///
   1.496 -      /// Gives back the running node of the iterator.
   1.497 -      /// It is always the source of the pointed arc.
   1.498 -      Node runningNode(const InArcIt&) const { return INVALID; }
   1.499 +      /// Returns the running node of the given outgoing arc iterator
   1.500 +      /// (i.e. the target node of the corresponding arc).
   1.501 +      Node runningNode(OutArcIt) const { return INVALID; }
   1.502  
   1.503        /// \brief The base node of the iterator.
   1.504        ///
   1.505 -      /// Gives back the base node of the iterator.
   1.506 -      /// It is always the source of the pointed arc.
   1.507 -      Node baseNode(const OutArcIt&) const { return INVALID; }
   1.508 +      /// Returns the base node of the given incomming arc iterator
   1.509 +      /// (i.e. the target node of the corresponding arc).
   1.510 +      Node baseNode(InArcIt) const { return INVALID; }
   1.511  
   1.512        /// \brief The running node of the iterator.
   1.513        ///
   1.514 -      /// Gives back the running node of the iterator.
   1.515 -      /// It is always the target of the pointed arc.
   1.516 -      Node runningNode(const OutArcIt&) const { return INVALID; }
   1.517 +      /// Returns the running node of the given incomming arc iterator
   1.518 +      /// (i.e. the source node of the corresponding arc).
   1.519 +      Node runningNode(InArcIt) const { return INVALID; }
   1.520  
   1.521 -      /// \brief The opposite node on the given arc.
   1.522 +      /// \brief Standard graph map type for the nodes.
   1.523        ///
   1.524 -      /// Gives back the opposite node on the given arc.
   1.525 -      Node oppositeNode(const Node&, const Arc&) const { return INVALID; }
   1.526 -
   1.527 -      /// \brief Reference map of the nodes to type \c T.
   1.528 -      ///
   1.529 -      /// Reference map of the nodes to type \c T.
   1.530 +      /// Standard graph map type for the nodes.
   1.531 +      /// It conforms to the ReferenceMap concept.
   1.532        template<class T>
   1.533        class NodeMap : public ReferenceMap<Node, T, T&, const T&> {
   1.534        public:
   1.535  
   1.536 -        ///\e
   1.537 -        NodeMap(const Digraph&) { }
   1.538 -        ///\e
   1.539 +        /// Constructor
   1.540 +        explicit NodeMap(const Digraph&) { }
   1.541 +        /// Constructor with given initial value
   1.542          NodeMap(const Digraph&, T) { }
   1.543  
   1.544        private:
   1.545 @@ -445,17 +444,19 @@
   1.546          }
   1.547        };
   1.548  
   1.549 -      /// \brief Reference map of the arcs to type \c T.
   1.550 +      /// \brief Standard graph map type for the arcs.
   1.551        ///
   1.552 -      /// Reference map of the arcs to type \c T.
   1.553 +      /// Standard graph map type for the arcs.
   1.554 +      /// It conforms to the ReferenceMap concept.
   1.555        template<class T>
   1.556        class ArcMap : public ReferenceMap<Arc, T, T&, const T&> {
   1.557        public:
   1.558  
   1.559 -        ///\e
   1.560 -        ArcMap(const Digraph&) { }
   1.561 -        ///\e
   1.562 +        /// Constructor
   1.563 +        explicit ArcMap(const Digraph&) { }
   1.564 +        /// Constructor with given initial value
   1.565          ArcMap(const Digraph&, T) { }
   1.566 +
   1.567        private:
   1.568          ///Copy constructor
   1.569          ArcMap(const ArcMap& em) :