lemon/list_graph.h
changeset 782 ceb2756dea2a
parent 740 819ca5b50de0
parent 739 32baeb8e5c8f
child 786 e20173729589
child 787 c2230649a493
     1.1 --- a/lemon/list_graph.h	Mon Sep 28 15:53:20 2009 +0200
     1.2 +++ b/lemon/list_graph.h	Thu Nov 05 10:27:17 2009 +0100
     1.3 @@ -21,7 +21,7 @@
     1.4  
     1.5  ///\ingroup graphs
     1.6  ///\file
     1.7 -///\brief ListDigraph, ListGraph classes.
     1.8 +///\brief ListDigraph and ListGraph classes.
     1.9  
    1.10  #include <lemon/core.h>
    1.11  #include <lemon/error.h>
    1.12 @@ -32,6 +32,8 @@
    1.13  
    1.14  namespace lemon {
    1.15  
    1.16 +  class ListDigraph;
    1.17 +
    1.18    class ListDigraphBase {
    1.19  
    1.20    protected:
    1.21 @@ -62,6 +64,7 @@
    1.22  
    1.23      class Node {
    1.24        friend class ListDigraphBase;
    1.25 +      friend class ListDigraph;
    1.26      protected:
    1.27  
    1.28        int id;
    1.29 @@ -77,6 +80,7 @@
    1.30  
    1.31      class Arc {
    1.32        friend class ListDigraphBase;
    1.33 +      friend class ListDigraph;
    1.34      protected:
    1.35  
    1.36        int id;
    1.37 @@ -116,20 +120,20 @@
    1.38      void first(Arc& arc) const {
    1.39        int n;
    1.40        for(n = first_node;
    1.41 -          n!=-1 && nodes[n].first_in == -1;
    1.42 +          n != -1 && nodes[n].first_out == -1;
    1.43            n = nodes[n].next) {}
    1.44 -      arc.id = (n == -1) ? -1 : nodes[n].first_in;
    1.45 +      arc.id = (n == -1) ? -1 : nodes[n].first_out;
    1.46      }
    1.47  
    1.48      void next(Arc& arc) const {
    1.49 -      if (arcs[arc.id].next_in != -1) {
    1.50 -        arc.id = arcs[arc.id].next_in;
    1.51 +      if (arcs[arc.id].next_out != -1) {
    1.52 +        arc.id = arcs[arc.id].next_out;
    1.53        } else {
    1.54          int n;
    1.55 -        for(n = nodes[arcs[arc.id].target].next;
    1.56 -            n!=-1 && nodes[n].first_in == -1;
    1.57 +        for(n = nodes[arcs[arc.id].source].next;
    1.58 +            n != -1 && nodes[n].first_out == -1;
    1.59              n = nodes[n].next) {}
    1.60 -        arc.id = (n == -1) ? -1 : nodes[n].first_in;
    1.61 +        arc.id = (n == -1) ? -1 : nodes[n].first_out;
    1.62        }
    1.63      }
    1.64  
    1.65 @@ -311,31 +315,25 @@
    1.66  
    1.67    ///A general directed graph structure.
    1.68  
    1.69 -  ///\ref ListDigraph is a simple and fast <em>directed graph</em>
    1.70 -  ///implementation based on static linked lists that are stored in
    1.71 +  ///\ref ListDigraph is a versatile and fast directed graph
    1.72 +  ///implementation based on linked lists that are stored in
    1.73    ///\c std::vector structures.
    1.74    ///
    1.75 -  ///It conforms to the \ref concepts::Digraph "Digraph concept" and it
    1.76 -  ///also provides several useful additional functionalities.
    1.77 -  ///Most of the member functions and nested classes are documented
    1.78 +  ///This type fully conforms to the \ref concepts::Digraph "Digraph concept"
    1.79 +  ///and it also provides several useful additional functionalities.
    1.80 +  ///Most of its member functions and nested classes are documented
    1.81    ///only in the concept class.
    1.82    ///
    1.83    ///\sa concepts::Digraph
    1.84 -
    1.85 +  ///\sa ListGraph
    1.86    class ListDigraph : public ExtendedListDigraphBase {
    1.87      typedef ExtendedListDigraphBase Parent;
    1.88  
    1.89    private:
    1.90 -    ///ListDigraph is \e not copy constructible. Use copyDigraph() instead.
    1.91 -
    1.92 -    ///ListDigraph is \e not copy constructible. Use copyDigraph() instead.
    1.93 -    ///
    1.94 +    /// Digraphs are \e not copy constructible. Use DigraphCopy instead.
    1.95      ListDigraph(const ListDigraph &) :ExtendedListDigraphBase() {};
    1.96 -    ///\brief Assignment of ListDigraph to another one is \e not allowed.
    1.97 -    ///Use copyDigraph() instead.
    1.98 -
    1.99 -    ///Assignment of ListDigraph to another one is \e not allowed.
   1.100 -    ///Use copyDigraph() instead.
   1.101 +    /// \brief Assignment of a digraph to another one is \e not allowed.
   1.102 +    /// Use DigraphCopy instead.
   1.103      void operator=(const ListDigraph &) {}
   1.104    public:
   1.105  
   1.106 @@ -347,71 +345,65 @@
   1.107  
   1.108      ///Add a new node to the digraph.
   1.109  
   1.110 -    ///Add a new node to the digraph.
   1.111 +    ///This function adds a new node to the digraph.
   1.112      ///\return The new node.
   1.113      Node addNode() { return Parent::addNode(); }
   1.114  
   1.115      ///Add a new arc to the digraph.
   1.116  
   1.117 -    ///Add a new arc to the digraph with source node \c s
   1.118 +    ///This function adds a new arc to the digraph with source node \c s
   1.119      ///and target node \c t.
   1.120      ///\return The new arc.
   1.121 -    Arc addArc(const Node& s, const Node& t) {
   1.122 +    Arc addArc(Node s, Node t) {
   1.123        return Parent::addArc(s, t);
   1.124      }
   1.125  
   1.126      ///\brief Erase a node from the digraph.
   1.127      ///
   1.128 -    ///Erase a node from the digraph.
   1.129 -    ///
   1.130 -    void erase(const Node& n) { Parent::erase(n); }
   1.131 +    ///This function erases the given node from the digraph.
   1.132 +    void erase(Node n) { Parent::erase(n); }
   1.133  
   1.134      ///\brief Erase an arc from the digraph.
   1.135      ///
   1.136 -    ///Erase an arc from the digraph.
   1.137 -    ///
   1.138 -    void erase(const Arc& a) { Parent::erase(a); }
   1.139 +    ///This function erases the given arc from the digraph.
   1.140 +    void erase(Arc a) { Parent::erase(a); }
   1.141  
   1.142      /// Node validity check
   1.143  
   1.144 -    /// This function gives back true if the given node is valid,
   1.145 -    /// ie. it is a real node of the graph.
   1.146 +    /// This function gives back \c true if the given node is valid,
   1.147 +    /// i.e. it is a real node of the digraph.
   1.148      ///
   1.149 -    /// \warning A Node pointing to a removed item
   1.150 -    /// could become valid again later if new nodes are
   1.151 -    /// added to the graph.
   1.152 +    /// \warning A removed node could become valid again if new nodes are
   1.153 +    /// added to the digraph.
   1.154      bool valid(Node n) const { return Parent::valid(n); }
   1.155  
   1.156      /// Arc validity check
   1.157  
   1.158 -    /// This function gives back true if the given arc is valid,
   1.159 -    /// ie. it is a real arc of the graph.
   1.160 +    /// This function gives back \c true if the given arc is valid,
   1.161 +    /// i.e. it is a real arc of the digraph.
   1.162      ///
   1.163 -    /// \warning An Arc pointing to a removed item
   1.164 -    /// could become valid again later if new nodes are
   1.165 -    /// added to the graph.
   1.166 +    /// \warning A removed arc could become valid again if new arcs are
   1.167 +    /// added to the digraph.
   1.168      bool valid(Arc a) const { return Parent::valid(a); }
   1.169  
   1.170 -    /// Change the target of \c a to \c n
   1.171 +    /// Change the target node of an arc
   1.172  
   1.173 -    /// Change the target of \c a to \c n
   1.174 +    /// This function changes the target node of the given arc \c a to \c n.
   1.175      ///
   1.176 -    ///\note The <tt>ArcIt</tt>s and <tt>OutArcIt</tt>s referencing
   1.177 -    ///the changed arc remain valid. However <tt>InArcIt</tt>s are
   1.178 -    ///invalidated.
   1.179 +    ///\note \c ArcIt and \c OutArcIt iterators referencing the changed
   1.180 +    ///arc remain valid, however \c InArcIt iterators are invalidated.
   1.181      ///
   1.182      ///\warning This functionality cannot be used together with the Snapshot
   1.183      ///feature.
   1.184      void changeTarget(Arc a, Node n) {
   1.185        Parent::changeTarget(a,n);
   1.186      }
   1.187 -    /// Change the source of \c a to \c n
   1.188 +    /// Change the source node of an arc
   1.189  
   1.190 -    /// Change the source of \c a to \c n
   1.191 +    /// This function changes the source node of the given arc \c a to \c n.
   1.192      ///
   1.193 -    ///\note The <tt>InArcIt</tt>s referencing the changed arc remain
   1.194 -    ///valid. However the <tt>ArcIt</tt>s and <tt>OutArcIt</tt>s are
   1.195 -    ///invalidated.
   1.196 +    ///\note \c InArcIt iterators referencing the changed arc remain
   1.197 +    ///valid, however \c ArcIt and \c OutArcIt iterators are invalidated.
   1.198      ///
   1.199      ///\warning This functionality cannot be used together with the Snapshot
   1.200      ///feature.
   1.201 @@ -419,94 +411,76 @@
   1.202        Parent::changeSource(a,n);
   1.203      }
   1.204  
   1.205 -    /// Invert the direction of an arc.
   1.206 +    /// Reverse the direction of an arc.
   1.207  
   1.208 -    ///\note The <tt>ArcIt</tt>s referencing the changed arc remain
   1.209 -    ///valid. However <tt>OutArcIt</tt>s and <tt>InArcIt</tt>s are
   1.210 -    ///invalidated.
   1.211 +    /// This function reverses the direction of the given arc.
   1.212 +    ///\note \c ArcIt, \c OutArcIt and \c InArcIt iterators referencing
   1.213 +    ///the changed arc are invalidated.
   1.214      ///
   1.215      ///\warning This functionality cannot be used together with the Snapshot
   1.216      ///feature.
   1.217 -    void reverseArc(Arc e) {
   1.218 -      Node t=target(e);
   1.219 -      changeTarget(e,source(e));
   1.220 -      changeSource(e,t);
   1.221 +    void reverseArc(Arc a) {
   1.222 +      Node t=target(a);
   1.223 +      changeTarget(a,source(a));
   1.224 +      changeSource(a,t);
   1.225      }
   1.226  
   1.227 -    /// Reserve memory for nodes.
   1.228 -
   1.229 -    /// Using this function it is possible to avoid the superfluous memory
   1.230 -    /// allocation: if you know that the digraph you want to build will
   1.231 -    /// be very large (e.g. it will contain millions of nodes and/or arcs)
   1.232 -    /// then it is worth reserving space for this amount before starting
   1.233 -    /// to build the digraph.
   1.234 -    /// \sa reserveArc
   1.235 -    void reserveNode(int n) { nodes.reserve(n); };
   1.236 -
   1.237 -    /// Reserve memory for arcs.
   1.238 -
   1.239 -    /// Using this function it is possible to avoid the superfluous memory
   1.240 -    /// allocation: if you know that the digraph you want to build will
   1.241 -    /// be very large (e.g. it will contain millions of nodes and/or arcs)
   1.242 -    /// then it is worth reserving space for this amount before starting
   1.243 -    /// to build the digraph.
   1.244 -    /// \sa reserveNode
   1.245 -    void reserveArc(int m) { arcs.reserve(m); };
   1.246 -
   1.247      ///Contract two nodes.
   1.248  
   1.249 -    ///This function contracts two nodes.
   1.250 -    ///Node \p b will be removed but instead of deleting
   1.251 -    ///incident arcs, they will be joined to \p a.
   1.252 -    ///The last parameter \p r controls whether to remove loops. \c true
   1.253 -    ///means that loops will be removed.
   1.254 +    ///This function contracts the given two nodes.
   1.255 +    ///Node \c v is removed, but instead of deleting its
   1.256 +    ///incident arcs, they are joined to node \c u.
   1.257 +    ///If the last parameter \c r is \c true (this is the default value),
   1.258 +    ///then the newly created loops are removed.
   1.259      ///
   1.260 -    ///\note The <tt>ArcIt</tt>s referencing a moved arc remain
   1.261 -    ///valid. However <tt>InArcIt</tt>s and <tt>OutArcIt</tt>s
   1.262 -    ///may be invalidated.
   1.263 +    ///\note The moved arcs are joined to node \c u using changeSource()
   1.264 +    ///or changeTarget(), thus \c ArcIt and \c OutArcIt iterators are
   1.265 +    ///invalidated for the outgoing arcs of node \c v and \c InArcIt
   1.266 +    ///iterators are invalidated for the incomming arcs of \c v.
   1.267 +    ///Moreover all iterators referencing node \c v or the removed 
   1.268 +    ///loops are also invalidated. Other iterators remain valid.
   1.269      ///
   1.270      ///\warning This functionality cannot be used together with the Snapshot
   1.271      ///feature.
   1.272 -    void contract(Node a, Node b, bool r = true)
   1.273 +    void contract(Node u, Node v, bool r = true)
   1.274      {
   1.275 -      for(OutArcIt e(*this,b);e!=INVALID;) {
   1.276 +      for(OutArcIt e(*this,v);e!=INVALID;) {
   1.277          OutArcIt f=e;
   1.278          ++f;
   1.279 -        if(r && target(e)==a) erase(e);
   1.280 -        else changeSource(e,a);
   1.281 +        if(r && target(e)==u) erase(e);
   1.282 +        else changeSource(e,u);
   1.283          e=f;
   1.284        }
   1.285 -      for(InArcIt e(*this,b);e!=INVALID;) {
   1.286 +      for(InArcIt e(*this,v);e!=INVALID;) {
   1.287          InArcIt f=e;
   1.288          ++f;
   1.289 -        if(r && source(e)==a) erase(e);
   1.290 -        else changeTarget(e,a);
   1.291 +        if(r && source(e)==u) erase(e);
   1.292 +        else changeTarget(e,u);
   1.293          e=f;
   1.294        }
   1.295 -      erase(b);
   1.296 +      erase(v);
   1.297      }
   1.298  
   1.299      ///Split a node.
   1.300  
   1.301 -    ///This function splits a node. First a new node is added to the digraph,
   1.302 -    ///then the source of each outgoing arc of \c n is moved to this new node.
   1.303 -    ///If \c connect is \c true (this is the default value), then a new arc
   1.304 -    ///from \c n to the newly created node is also added.
   1.305 +    ///This function splits the given node. First, a new node is added
   1.306 +    ///to the digraph, then the source of each outgoing arc of node \c n
   1.307 +    ///is moved to this new node.
   1.308 +    ///If the second parameter \c connect is \c true (this is the default
   1.309 +    ///value), then a new arc from node \c n to the newly created node
   1.310 +    ///is also added.
   1.311      ///\return The newly created node.
   1.312      ///
   1.313 -    ///\note The <tt>ArcIt</tt>s referencing a moved arc remain
   1.314 -    ///valid. However <tt>InArcIt</tt>s and <tt>OutArcIt</tt>s may
   1.315 -    ///be invalidated.
   1.316 +    ///\note All iterators remain valid.
   1.317      ///
   1.318 -    ///\warning This functionality cannot be used in conjunction with the
   1.319 +    ///\warning This functionality cannot be used together with the
   1.320      ///Snapshot feature.
   1.321      Node split(Node n, bool connect = true) {
   1.322        Node b = addNode();
   1.323 -      for(OutArcIt e(*this,n);e!=INVALID;) {
   1.324 -        OutArcIt f=e;
   1.325 -        ++f;
   1.326 -        changeSource(e,b);
   1.327 -        e=f;
   1.328 +      nodes[b.id].first_out=nodes[n.id].first_out;
   1.329 +      nodes[n.id].first_out=-1;
   1.330 +      for(int i=nodes[b.id].first_out; i!=-1; i=arcs[i].next_out) {
   1.331 +        arcs[i].source=b.id;
   1.332        }
   1.333        if (connect) addArc(n,b);
   1.334        return b;
   1.335 @@ -514,21 +488,52 @@
   1.336  
   1.337      ///Split an arc.
   1.338  
   1.339 -    ///This function splits an arc. First a new node \c b is added to
   1.340 -    ///the digraph, then the original arc is re-targeted to \c
   1.341 -    ///b. Finally an arc from \c b to the original target is added.
   1.342 +    ///This function splits the given arc. First, a new node \c v is
   1.343 +    ///added to the digraph, then the target node of the original arc
   1.344 +    ///is set to \c v. Finally, an arc from \c v to the original target
   1.345 +    ///is added.
   1.346 +    ///\return The newly created node.
   1.347      ///
   1.348 -    ///\return The newly created node.
   1.349 +    ///\note \c InArcIt iterators referencing the original arc are
   1.350 +    ///invalidated. Other iterators remain valid.
   1.351      ///
   1.352      ///\warning This functionality cannot be used together with the
   1.353      ///Snapshot feature.
   1.354 -    Node split(Arc e) {
   1.355 -      Node b = addNode();
   1.356 -      addArc(b,target(e));
   1.357 -      changeTarget(e,b);
   1.358 -      return b;
   1.359 +    Node split(Arc a) {
   1.360 +      Node v = addNode();
   1.361 +      addArc(v,target(a));
   1.362 +      changeTarget(a,v);
   1.363 +      return v;
   1.364      }
   1.365  
   1.366 +    ///Clear the digraph.
   1.367 +
   1.368 +    ///This function erases all nodes and arcs from the digraph.
   1.369 +    ///
   1.370 +    void clear() {
   1.371 +      Parent::clear();
   1.372 +    }
   1.373 +
   1.374 +    /// Reserve memory for nodes.
   1.375 +
   1.376 +    /// Using this function, it is possible to avoid superfluous memory
   1.377 +    /// allocation: if you know that the digraph you want to build will
   1.378 +    /// be large (e.g. it will contain millions of nodes and/or arcs),
   1.379 +    /// then it is worth reserving space for this amount before starting
   1.380 +    /// to build the digraph.
   1.381 +    /// \sa reserveArc()
   1.382 +    void reserveNode(int n) { nodes.reserve(n); };
   1.383 +
   1.384 +    /// Reserve memory for arcs.
   1.385 +
   1.386 +    /// Using this function, it is possible to avoid superfluous memory
   1.387 +    /// allocation: if you know that the digraph you want to build will
   1.388 +    /// be large (e.g. it will contain millions of nodes and/or arcs),
   1.389 +    /// then it is worth reserving space for this amount before starting
   1.390 +    /// to build the digraph.
   1.391 +    /// \sa reserveNode()
   1.392 +    void reserveArc(int m) { arcs.reserve(m); };
   1.393 +
   1.394      /// \brief Class to make a snapshot of the digraph and restore
   1.395      /// it later.
   1.396      ///
   1.397 @@ -537,9 +542,15 @@
   1.398      /// The newly added nodes and arcs can be removed using the
   1.399      /// restore() function.
   1.400      ///
   1.401 -    /// \warning Arc and node deletions and other modifications (e.g.
   1.402 -    /// contracting, splitting, reversing arcs or nodes) cannot be
   1.403 +    /// \note After a state is restored, you cannot restore a later state, 
   1.404 +    /// i.e. you cannot add the removed nodes and arcs again using
   1.405 +    /// another Snapshot instance.
   1.406 +    ///
   1.407 +    /// \warning Node and arc deletions and other modifications (e.g.
   1.408 +    /// reversing, contracting, splitting arcs or nodes) cannot be
   1.409      /// restored. These events invalidate the snapshot.
   1.410 +    /// However the arcs and nodes that were added to the digraph after
   1.411 +    /// making the current snapshot can be removed without invalidating it.
   1.412      class Snapshot {
   1.413      protected:
   1.414  
   1.415 @@ -709,39 +720,40 @@
   1.416        /// \brief Default constructor.
   1.417        ///
   1.418        /// Default constructor.
   1.419 -      /// To actually make a snapshot you must call save().
   1.420 +      /// You have to call save() to actually make a snapshot.
   1.421        Snapshot()
   1.422          : digraph(0), node_observer_proxy(*this),
   1.423            arc_observer_proxy(*this) {}
   1.424  
   1.425        /// \brief Constructor that immediately makes a snapshot.
   1.426        ///
   1.427 -      /// This constructor immediately makes a snapshot of the digraph.
   1.428 -      /// \param _digraph The digraph we make a snapshot of.
   1.429 -      Snapshot(ListDigraph &_digraph)
   1.430 +      /// This constructor immediately makes a snapshot of the given digraph.
   1.431 +      Snapshot(ListDigraph &gr)
   1.432          : node_observer_proxy(*this),
   1.433            arc_observer_proxy(*this) {
   1.434 -        attach(_digraph);
   1.435 +        attach(gr);
   1.436        }
   1.437  
   1.438        /// \brief Make a snapshot.
   1.439        ///
   1.440 -      /// Make a snapshot of the digraph.
   1.441 -      ///
   1.442 -      /// This function can be called more than once. In case of a repeated
   1.443 +      /// This function makes a snapshot of the given digraph.
   1.444 +      /// It can be called more than once. In case of a repeated
   1.445        /// call, the previous snapshot gets lost.
   1.446 -      /// \param _digraph The digraph we make the snapshot of.
   1.447 -      void save(ListDigraph &_digraph) {
   1.448 +      void save(ListDigraph &gr) {
   1.449          if (attached()) {
   1.450            detach();
   1.451            clear();
   1.452          }
   1.453 -        attach(_digraph);
   1.454 +        attach(gr);
   1.455        }
   1.456  
   1.457        /// \brief Undo the changes until the last snapshot.
   1.458 -      //
   1.459 -      /// Undo the changes until the last snapshot created by save().
   1.460 +      ///
   1.461 +      /// This function undos the changes until the last snapshot
   1.462 +      /// created by save() or Snapshot(ListDigraph&).
   1.463 +      ///
   1.464 +      /// \warning This method invalidates the snapshot, i.e. repeated
   1.465 +      /// restoring is not supported unless you call save() again.
   1.466        void restore() {
   1.467          detach();
   1.468          for(std::list<Arc>::iterator it = added_arcs.begin();
   1.469 @@ -755,9 +767,9 @@
   1.470          clear();
   1.471        }
   1.472  
   1.473 -      /// \brief Gives back true when the snapshot is valid.
   1.474 +      /// \brief Returns \c true if the snapshot is valid.
   1.475        ///
   1.476 -      /// Gives back true when the snapshot is valid.
   1.477 +      /// This function returns \c true if the snapshot is valid.
   1.478        bool valid() const {
   1.479          return attached();
   1.480        }
   1.481 @@ -795,10 +807,6 @@
   1.482  
   1.483      typedef ListGraphBase Graph;
   1.484  
   1.485 -    class Node;
   1.486 -    class Arc;
   1.487 -    class Edge;
   1.488 -
   1.489      class Node {
   1.490        friend class ListGraphBase;
   1.491      protected:
   1.492 @@ -848,8 +856,6 @@
   1.493        bool operator<(const Arc& arc) const {return id < arc.id;}
   1.494      };
   1.495  
   1.496 -
   1.497 -
   1.498      ListGraphBase()
   1.499        : nodes(), first_node(-1),
   1.500          first_free_node(-1), arcs(), first_free_arc(-1) {}
   1.501 @@ -1164,31 +1170,25 @@
   1.502  
   1.503    ///A general undirected graph structure.
   1.504  
   1.505 -  ///\ref ListGraph is a simple and fast <em>undirected graph</em>
   1.506 -  ///implementation based on static linked lists that are stored in
   1.507 +  ///\ref ListGraph is a versatile and fast undirected graph
   1.508 +  ///implementation based on linked lists that are stored in
   1.509    ///\c std::vector structures.
   1.510    ///
   1.511 -  ///It conforms to the \ref concepts::Graph "Graph concept" and it
   1.512 -  ///also provides several useful additional functionalities.
   1.513 -  ///Most of the member functions and nested classes are documented
   1.514 +  ///This type fully conforms to the \ref concepts::Graph "Graph concept"
   1.515 +  ///and it also provides several useful additional functionalities.
   1.516 +  ///Most of its member functions and nested classes are documented
   1.517    ///only in the concept class.
   1.518    ///
   1.519    ///\sa concepts::Graph
   1.520 -
   1.521 +  ///\sa ListDigraph
   1.522    class ListGraph : public ExtendedListGraphBase {
   1.523      typedef ExtendedListGraphBase Parent;
   1.524  
   1.525    private:
   1.526 -    ///ListGraph is \e not copy constructible. Use copyGraph() instead.
   1.527 -
   1.528 -    ///ListGraph is \e not copy constructible. Use copyGraph() instead.
   1.529 -    ///
   1.530 +    /// Graphs are \e not copy constructible. Use GraphCopy instead.
   1.531      ListGraph(const ListGraph &) :ExtendedListGraphBase()  {};
   1.532 -    ///\brief Assignment of ListGraph to another one is \e not allowed.
   1.533 -    ///Use copyGraph() instead.
   1.534 -
   1.535 -    ///Assignment of ListGraph to another one is \e not allowed.
   1.536 -    ///Use copyGraph() instead.
   1.537 +    /// \brief Assignment of a graph to another one is \e not allowed.
   1.538 +    /// Use GraphCopy instead.
   1.539      void operator=(const ListGraph &) {}
   1.540    public:
   1.541      /// Constructor
   1.542 @@ -1201,94 +1201,95 @@
   1.543  
   1.544      /// \brief Add a new node to the graph.
   1.545      ///
   1.546 -    /// Add a new node to the graph.
   1.547 +    /// This function adds a new node to the graph.
   1.548      /// \return The new node.
   1.549      Node addNode() { return Parent::addNode(); }
   1.550  
   1.551      /// \brief Add a new edge to the graph.
   1.552      ///
   1.553 -    /// Add a new edge to the graph with source node \c s
   1.554 -    /// and target node \c t.
   1.555 +    /// This function adds a new edge to the graph between nodes
   1.556 +    /// \c u and \c v with inherent orientation from node \c u to
   1.557 +    /// node \c v.
   1.558      /// \return The new edge.
   1.559 -    Edge addEdge(const Node& s, const Node& t) {
   1.560 -      return Parent::addEdge(s, t);
   1.561 +    Edge addEdge(Node u, Node v) {
   1.562 +      return Parent::addEdge(u, v);
   1.563      }
   1.564  
   1.565 -    /// \brief Erase a node from the graph.
   1.566 +    ///\brief Erase a node from the graph.
   1.567      ///
   1.568 -    /// Erase a node from the graph.
   1.569 +    /// This function erases the given node from the graph.
   1.570 +    void erase(Node n) { Parent::erase(n); }
   1.571 +
   1.572 +    ///\brief Erase an edge from the graph.
   1.573      ///
   1.574 -    void erase(const Node& n) { Parent::erase(n); }
   1.575 -
   1.576 -    /// \brief Erase an edge from the graph.
   1.577 -    ///
   1.578 -    /// Erase an edge from the graph.
   1.579 -    ///
   1.580 -    void erase(const Edge& e) { Parent::erase(e); }
   1.581 +    /// This function erases the given edge from the graph.
   1.582 +    void erase(Edge e) { Parent::erase(e); }
   1.583      /// Node validity check
   1.584  
   1.585 -    /// This function gives back true if the given node is valid,
   1.586 -    /// ie. it is a real node of the graph.
   1.587 +    /// This function gives back \c true if the given node is valid,
   1.588 +    /// i.e. it is a real node of the graph.
   1.589      ///
   1.590 -    /// \warning A Node pointing to a removed item
   1.591 -    /// could become valid again later if new nodes are
   1.592 +    /// \warning A removed node could become valid again if new nodes are
   1.593      /// added to the graph.
   1.594      bool valid(Node n) const { return Parent::valid(n); }
   1.595 +    /// Edge validity check
   1.596 +
   1.597 +    /// This function gives back \c true if the given edge is valid,
   1.598 +    /// i.e. it is a real edge of the graph.
   1.599 +    ///
   1.600 +    /// \warning A removed edge could become valid again if new edges are
   1.601 +    /// added to the graph.
   1.602 +    bool valid(Edge e) const { return Parent::valid(e); }
   1.603      /// Arc validity check
   1.604  
   1.605 -    /// This function gives back true if the given arc is valid,
   1.606 -    /// ie. it is a real arc of the graph.
   1.607 +    /// This function gives back \c true if the given arc is valid,
   1.608 +    /// i.e. it is a real arc of the graph.
   1.609      ///
   1.610 -    /// \warning An Arc pointing to a removed item
   1.611 -    /// could become valid again later if new edges are
   1.612 +    /// \warning A removed arc could become valid again if new edges are
   1.613      /// added to the graph.
   1.614      bool valid(Arc a) const { return Parent::valid(a); }
   1.615 -    /// Edge validity check
   1.616  
   1.617 -    /// This function gives back true if the given edge is valid,
   1.618 -    /// ie. it is a real arc of the graph.
   1.619 +    /// \brief Change the first node of an edge.
   1.620      ///
   1.621 -    /// \warning A Edge pointing to a removed item
   1.622 -    /// could become valid again later if new edges are
   1.623 -    /// added to the graph.
   1.624 -    bool valid(Edge e) const { return Parent::valid(e); }
   1.625 -    /// \brief Change the end \c u of \c e to \c n
   1.626 +    /// This function changes the first node of the given edge \c e to \c n.
   1.627      ///
   1.628 -    /// This function changes the end \c u of \c e to node \c n.
   1.629 -    ///
   1.630 -    ///\note The <tt>EdgeIt</tt>s and <tt>ArcIt</tt>s referencing the
   1.631 -    ///changed edge are invalidated and if the changed node is the
   1.632 -    ///base node of an iterator then this iterator is also
   1.633 -    ///invalidated.
   1.634 +    ///\note \c EdgeIt and \c ArcIt iterators referencing the
   1.635 +    ///changed edge are invalidated and all other iterators whose
   1.636 +    ///base node is the changed node are also invalidated.
   1.637      ///
   1.638      ///\warning This functionality cannot be used together with the
   1.639      ///Snapshot feature.
   1.640      void changeU(Edge e, Node n) {
   1.641        Parent::changeU(e,n);
   1.642      }
   1.643 -    /// \brief Change the end \c v of \c e to \c n
   1.644 +    /// \brief Change the second node of an edge.
   1.645      ///
   1.646 -    /// This function changes the end \c v of \c e to \c n.
   1.647 +    /// This function changes the second node of the given edge \c e to \c n.
   1.648      ///
   1.649 -    ///\note The <tt>EdgeIt</tt>s referencing the changed edge remain
   1.650 -    ///valid, however <tt>ArcIt</tt>s and if the changed node is the
   1.651 -    ///base node of an iterator then this iterator is invalidated.
   1.652 +    ///\note \c EdgeIt iterators referencing the changed edge remain
   1.653 +    ///valid, however \c ArcIt iterators referencing the changed edge and
   1.654 +    ///all other iterators whose base node is the changed node are also
   1.655 +    ///invalidated.
   1.656      ///
   1.657      ///\warning This functionality cannot be used together with the
   1.658      ///Snapshot feature.
   1.659      void changeV(Edge e, Node n) {
   1.660        Parent::changeV(e,n);
   1.661      }
   1.662 +
   1.663      /// \brief Contract two nodes.
   1.664      ///
   1.665 -    /// This function contracts two nodes.
   1.666 -    /// Node \p b will be removed but instead of deleting
   1.667 -    /// its neighboring arcs, they will be joined to \p a.
   1.668 -    /// The last parameter \p r controls whether to remove loops. \c true
   1.669 -    /// means that loops will be removed.
   1.670 +    /// This function contracts the given two nodes.
   1.671 +    /// Node \c b is removed, but instead of deleting
   1.672 +    /// its incident edges, they are joined to node \c a.
   1.673 +    /// If the last parameter \c r is \c true (this is the default value),
   1.674 +    /// then the newly created loops are removed.
   1.675      ///
   1.676 -    /// \note The <tt>ArcIt</tt>s referencing a moved arc remain
   1.677 -    /// valid.
   1.678 +    /// \note The moved edges are joined to node \c a using changeU()
   1.679 +    /// or changeV(), thus all edge and arc iterators whose base node is
   1.680 +    /// \c b are invalidated.
   1.681 +    /// Moreover all iterators referencing node \c b or the removed 
   1.682 +    /// loops are also invalidated. Other iterators remain valid.
   1.683      ///
   1.684      ///\warning This functionality cannot be used together with the
   1.685      ///Snapshot feature.
   1.686 @@ -1307,6 +1308,33 @@
   1.687        erase(b);
   1.688      }
   1.689  
   1.690 +    ///Clear the graph.
   1.691 +
   1.692 +    ///This function erases all nodes and arcs from the graph.
   1.693 +    ///
   1.694 +    void clear() {
   1.695 +      Parent::clear();
   1.696 +    }
   1.697 +
   1.698 +    /// Reserve memory for nodes.
   1.699 +
   1.700 +    /// Using this function, it is possible to avoid superfluous memory
   1.701 +    /// allocation: if you know that the graph you want to build will
   1.702 +    /// be large (e.g. it will contain millions of nodes and/or edges),
   1.703 +    /// then it is worth reserving space for this amount before starting
   1.704 +    /// to build the graph.
   1.705 +    /// \sa reserveEdge()
   1.706 +    void reserveNode(int n) { nodes.reserve(n); };
   1.707 +
   1.708 +    /// Reserve memory for edges.
   1.709 +
   1.710 +    /// Using this function, it is possible to avoid superfluous memory
   1.711 +    /// allocation: if you know that the graph you want to build will
   1.712 +    /// be large (e.g. it will contain millions of nodes and/or edges),
   1.713 +    /// then it is worth reserving space for this amount before starting
   1.714 +    /// to build the graph.
   1.715 +    /// \sa reserveNode()
   1.716 +    void reserveEdge(int m) { arcs.reserve(2 * m); };
   1.717  
   1.718      /// \brief Class to make a snapshot of the graph and restore
   1.719      /// it later.
   1.720 @@ -1316,9 +1344,15 @@
   1.721      /// The newly added nodes and edges can be removed
   1.722      /// using the restore() function.
   1.723      ///
   1.724 -    /// \warning Edge and node deletions and other modifications
   1.725 -    /// (e.g. changing nodes of edges, contracting nodes) cannot be
   1.726 -    /// restored. These events invalidate the snapshot.
   1.727 +    /// \note After a state is restored, you cannot restore a later state, 
   1.728 +    /// i.e. you cannot add the removed nodes and edges again using
   1.729 +    /// another Snapshot instance.
   1.730 +    ///
   1.731 +    /// \warning Node and edge deletions and other modifications
   1.732 +    /// (e.g. changing the end-nodes of edges or contracting nodes)
   1.733 +    /// cannot be restored. These events invalidate the snapshot.
   1.734 +    /// However the edges and nodes that were added to the graph after
   1.735 +    /// making the current snapshot can be removed without invalidating it.
   1.736      class Snapshot {
   1.737      protected:
   1.738  
   1.739 @@ -1488,39 +1522,40 @@
   1.740        /// \brief Default constructor.
   1.741        ///
   1.742        /// Default constructor.
   1.743 -      /// To actually make a snapshot you must call save().
   1.744 +      /// You have to call save() to actually make a snapshot.
   1.745        Snapshot()
   1.746          : graph(0), node_observer_proxy(*this),
   1.747            edge_observer_proxy(*this) {}
   1.748  
   1.749        /// \brief Constructor that immediately makes a snapshot.
   1.750        ///
   1.751 -      /// This constructor immediately makes a snapshot of the graph.
   1.752 -      /// \param _graph The graph we make a snapshot of.
   1.753 -      Snapshot(ListGraph &_graph)
   1.754 +      /// This constructor immediately makes a snapshot of the given graph.
   1.755 +      Snapshot(ListGraph &gr)
   1.756          : node_observer_proxy(*this),
   1.757            edge_observer_proxy(*this) {
   1.758 -        attach(_graph);
   1.759 +        attach(gr);
   1.760        }
   1.761  
   1.762        /// \brief Make a snapshot.
   1.763        ///
   1.764 -      /// Make a snapshot of the graph.
   1.765 -      ///
   1.766 -      /// This function can be called more than once. In case of a repeated
   1.767 +      /// This function makes a snapshot of the given graph.
   1.768 +      /// It can be called more than once. In case of a repeated
   1.769        /// call, the previous snapshot gets lost.
   1.770 -      /// \param _graph The graph we make the snapshot of.
   1.771 -      void save(ListGraph &_graph) {
   1.772 +      void save(ListGraph &gr) {
   1.773          if (attached()) {
   1.774            detach();
   1.775            clear();
   1.776          }
   1.777 -        attach(_graph);
   1.778 +        attach(gr);
   1.779        }
   1.780  
   1.781        /// \brief Undo the changes until the last snapshot.
   1.782 -      //
   1.783 -      /// Undo the changes until the last snapshot created by save().
   1.784 +      ///
   1.785 +      /// This function undos the changes until the last snapshot
   1.786 +      /// created by save() or Snapshot(ListGraph&).
   1.787 +      ///
   1.788 +      /// \warning This method invalidates the snapshot, i.e. repeated
   1.789 +      /// restoring is not supported unless you call save() again.
   1.790        void restore() {
   1.791          detach();
   1.792          for(std::list<Edge>::iterator it = added_edges.begin();
   1.793 @@ -1534,9 +1569,9 @@
   1.794          clear();
   1.795        }
   1.796  
   1.797 -      /// \brief Gives back true when the snapshot is valid.
   1.798 +      /// \brief Returns \c true if the snapshot is valid.
   1.799        ///
   1.800 -      /// Gives back true when the snapshot is valid.
   1.801 +      /// This function returns \c true if the snapshot is valid.
   1.802        bool valid() const {
   1.803          return attached();
   1.804        }