src/work/marci/graph_wrapper.h
author beckerjc
Sat, 17 Apr 2004 19:34:43 +0000
changeset 350 3a9a767b841e
parent 341 6046b1d0f267
child 356 b4dcbe3e3b8f
permissions -rw-r--r--
Maximum Adjacency Ordering (beta)
     1 // -*- c++ -*-
     2 #ifndef HUGO_GRAPH_WRAPPER_H
     3 #define HUGO_GRAPH_WRAPPER_H
     4 
     5 #include <invalid.h>
     6 
     7 namespace hugo {
     8 
     9   /// Graph wrappers
    10 
    11   /// A main parts of HUGOlib are the different graph structures, 
    12   /// generic graph algorithms, graph concepts which couple these, and 
    13   /// graph wrappers. While the previous ones are more or less clear, the 
    14   /// latter notion needs further explanation.
    15   /// Graph wrappers are graph classes which serve for considering graph 
    16   /// structures in different ways. A short example makes the notion much 
    17   /// clearer. 
    18   /// Suppose that we have an instance \c g of a directed graph
    19   /// type say \c ListGraph and an algorithm 
    20   /// \code template<typename Graph> int algorithm(const Graph&); \endcode 
    21   /// is needed to run on the reversely oriented graph. 
    22   /// It may be expensive (in time or in memory usage) to copy 
    23   /// \c g with the reverse orientation. 
    24   /// Thus, a wrapper class
    25   /// \code template<typename Graph> class RevGraphWrapper; \endcode is used. 
    26   /// The code looks as follows
    27   /// \code
    28   /// ListGraph g;
    29   /// RevGraphWrapper<ListGraph> rgw(g);
    30   /// int result=algorithm(rgw);
    31   /// \endcode
    32   /// After running the algorithm, the original graph \c g 
    33   /// remains untouched. Thus the graph wrapper used above is to consider the 
    34   /// original graph with reverse orientation. 
    35   /// This techniques gives rise to an elegant code, and 
    36   /// based on stable graph wrappers, complex algorithms can be 
    37   /// implemented easily. 
    38   /// In flow, circulation and bipartite matching problems, the residual 
    39   /// graph is of particular importance. Combining a wrapper implementing 
    40   /// this, shortest path algorithms and minimum mean cycle algorithms, 
    41   /// a range of weighted and cardinality optimization algorithms can be 
    42   /// obtained. For lack of space, for other examples, 
    43   /// the interested user is referred to the detailed documentation of graph 
    44   /// wrappers. 
    45   /// The behavior of graph wrappers can be very different. Some of them keep 
    46   /// capabilities of the original graph while in other cases this would be 
    47   /// meaningless. This means that the concepts that they are a model of depend 
    48   /// on the graph wrapper, and the wrapped graph(s). 
    49   /// If an edge of \c rgw is deleted, this is carried out by 
    50   /// deleting the corresponding edge of \c g. But for a residual 
    51   /// graph, this operation has no sense. 
    52   /// Let we stand one more example here to simplify your work. 
    53   /// wrapper class
    54   /// \code template<typename Graph> class RevGraphWrapper; \endcode 
    55   /// has constructor 
    56   /// <tt> RevGraphWrapper(Graph& _g)</tt>. 
    57   /// This means that in a situation, 
    58   /// when a <tt> const ListGraph& </tt> reference to a graph is given, 
    59   /// then it have to be instantiated with <tt>Graph=const ListGraph</tt>.
    60   /// \code
    61   /// int algorithm1(const ListGraph& g) {
    62   ///   RevGraphWrapper<const ListGraph> rgw(g);
    63   ///   return algorithm2(rgw);
    64   /// }
    65   /// \endcode
    66   template<typename Graph>
    67   class GraphWrapper {
    68   protected:
    69     Graph* graph;
    70   
    71   public:
    72     typedef Graph BaseGraph;
    73     typedef Graph ParentGraph;
    74 
    75 //     GraphWrapper() : graph(0) { }
    76     GraphWrapper(Graph& _graph) : graph(&_graph) { }
    77 //     void setGraph(Graph& _graph) { graph=&_graph; }
    78 //     Graph& getGraph() const { return *graph; }
    79  
    80 //    typedef typename Graph::Node Node;
    81     class Node : public Graph::Node {
    82       friend class GraphWrapper<Graph>;
    83     public:
    84       Node() { }
    85       Node(const typename Graph::Node& _n) : Graph::Node(_n) { }
    86       Node(const Invalid& i) : Graph::Node(i) { }
    87     };
    88     class NodeIt { 
    89       friend class GraphWrapper<Graph>;
    90       typename Graph::NodeIt n;
    91      public:
    92       NodeIt() { }
    93       NodeIt(const typename Graph::NodeIt& _n) : n(_n) { }
    94       NodeIt(const Invalid& i) : n(i) { }
    95       NodeIt(const GraphWrapper<Graph>& _G) : n(*(_G.graph)) { }
    96       operator Node() const { return Node(typename Graph::Node(n)); }
    97     };
    98 //    typedef typename Graph::Edge Edge;
    99     class Edge : public Graph::Edge {
   100       friend class GraphWrapper<Graph>;
   101     public:
   102       Edge() { }
   103       Edge(const typename Graph::Edge& _e) : Graph::Edge(_e) { }
   104       Edge(const Invalid& i) : Graph::Edge(i) { }
   105     };
   106     class OutEdgeIt { 
   107       friend class GraphWrapper<Graph>;
   108       typename Graph::OutEdgeIt e;
   109     public:
   110       OutEdgeIt() { }
   111       OutEdgeIt(const typename Graph::OutEdgeIt& _e) : e(_e) { }
   112       OutEdgeIt(const Invalid& i) : e(i) { }
   113       OutEdgeIt(const GraphWrapper<Graph>& _G, const Node& _n) : 
   114 	e(*(_G.graph), typename Graph::Node(_n)) { }
   115       operator Edge() const { return Edge(typename Graph::Edge(e)); }
   116     };
   117     class InEdgeIt { 
   118       friend class GraphWrapper<Graph>;
   119       typename Graph::InEdgeIt e;
   120     public:
   121       InEdgeIt() { }
   122       InEdgeIt(const typename Graph::InEdgeIt& _e) : e(_e) { }
   123       InEdgeIt(const Invalid& i) : e(i) { }
   124       InEdgeIt(const GraphWrapper<Graph>& _G, const Node& _n) : 
   125 	e(*(_G.graph), typename Graph::Node(_n)) { }
   126       operator Edge() const { return Edge(typename Graph::Edge(e)); }
   127     };
   128     //typedef typename Graph::SymEdgeIt SymEdgeIt;
   129     class EdgeIt { 
   130       friend class GraphWrapper<Graph>;
   131       typename Graph::EdgeIt e;
   132     public:
   133       EdgeIt() { }
   134       EdgeIt(const typename Graph::EdgeIt& _e) : e(_e) { }
   135       EdgeIt(const Invalid& i) : e(i) { }
   136       EdgeIt(const GraphWrapper<Graph>& _G) : e(*(_G.graph)) { }
   137       operator Edge() const { return Edge(typename Graph::Edge(e)); }
   138     };
   139    
   140     NodeIt& first(NodeIt& i) const { 
   141       i=NodeIt(*this); return i;
   142     }
   143     OutEdgeIt& first(OutEdgeIt& i, const Node& p) const { 
   144       i=OutEdgeIt(*this, p); return i;
   145     }
   146     InEdgeIt& first(InEdgeIt& i, const Node& p) const { 
   147       i=InEdgeIt(*this, p); return i;
   148     }
   149     EdgeIt& first(EdgeIt& i) const { 
   150       i=EdgeIt(*this); return i;
   151     }
   152 
   153     NodeIt& next(NodeIt& i) const { graph->next(i.n); return i; }
   154     OutEdgeIt& next(OutEdgeIt& i) const { graph->next(i.e); return i; }
   155     InEdgeIt& next(InEdgeIt& i) const { graph->next(i.e); return i; }
   156     EdgeIt& next(EdgeIt& i) const { graph->next(i.e); return i; }    
   157 
   158     Node head(const Edge& e) const { 
   159       return Node(graph->head(static_cast<typename Graph::Edge>(e))); }
   160     Node tail(const Edge& e) const { 
   161       return Node(graph->tail(static_cast<typename Graph::Edge>(e))); }
   162 
   163     bool valid(const Node& n) const { 
   164       return graph->valid(static_cast<typename Graph::Node>(n)); }
   165     bool valid(const Edge& e) const { 
   166       return graph->valid(static_cast<typename Graph::Edge>(e)); }
   167 
   168     int nodeNum() const { return graph->nodeNum(); }
   169     int edgeNum() const { return graph->edgeNum(); }
   170   
   171     Node aNode(const OutEdgeIt& e) const { return Node(graph->aNode(e.e)); }
   172     Node aNode(const InEdgeIt& e) const { return Node(graph->aNode(e.e)); }
   173     Node bNode(const OutEdgeIt& e) const { return Node(graph->bNode(e.e)); }
   174     Node bNode(const InEdgeIt& e) const { return Node(graph->bNode(e.e)); }
   175   
   176     Node addNode() const { return Node(graph->addNode()); }
   177     Edge addEdge(const Node& tail, const Node& head) const { 
   178       return Edge(graph->addEdge(tail, head)); }
   179 
   180     void erase(const Node& i) const { graph->erase(i); }
   181     void erase(const Edge& i) const { graph->erase(i); }
   182   
   183     void clear() const { graph->clear(); }
   184     
   185     template<typename T> class NodeMap : public Graph::NodeMap<T> { 
   186     public:
   187       NodeMap(const GraphWrapper<Graph>& _G) :  
   188 	Graph::NodeMap<T>(*(_G.graph)) { }
   189       NodeMap(const GraphWrapper<Graph>& _G, T a) : 
   190 	Graph::NodeMap<T>(*(_G.graph), a) { }
   191     };
   192 
   193     template<typename T> class EdgeMap : public Graph::EdgeMap<T> { 
   194     public:
   195       EdgeMap(const GraphWrapper<Graph>& _G) :  
   196 	Graph::EdgeMap<T>(*(_G.graph)) { }
   197       EdgeMap(const GraphWrapper<Graph>& _G, T a) : 
   198 	Graph::EdgeMap<T>(*(_G.graph), a) { }
   199     };
   200   };
   201 
   202   /// A graph wrapper which reverses the orientation of the edges.
   203 
   204   /// A graph wrapper which reverses the orientation of the edges.
   205   template<typename Graph>
   206   class RevGraphWrapper : public GraphWrapper<Graph> {
   207   public:
   208 
   209     RevGraphWrapper(Graph& _graph) : GraphWrapper<Graph>(_graph) { }  
   210 
   211     typedef typename GraphWrapper<Graph>::Node Node;
   212     typedef typename GraphWrapper<Graph>::Edge Edge;
   213     //If Graph::OutEdgeIt is not defined
   214     //and we do not want to use RevGraphWrapper::InEdgeIt,
   215     //the typdef techinque does not work.
   216     //Unfortunately all the typedefs are instantiated in templates.
   217     //typedef typename GraphWrapper<Graph>::OutEdgeIt InEdgeIt;
   218     //typedef typename GraphWrapper<Graph>::InEdgeIt OutEdgeIt;
   219 
   220     class OutEdgeIt { 
   221       friend class GraphWrapper<Graph>;
   222       friend class RevGraphWrapper<Graph>;
   223       typename Graph::OutEdgeIt e;
   224     public:
   225       OutEdgeIt() { }
   226       OutEdgeIt(const typename Graph::OutEdgeIt& _e) : e(_e) { }
   227       OutEdgeIt(const Invalid& i) : e(i) { }
   228       OutEdgeIt(const RevGraphWrapper<Graph>& _G, const Node& _n) : 
   229 	e(*(_G.graph), typename Graph::Node(_n)) { }
   230       operator Edge() const { return Edge(typename Graph::Edge(e)); }
   231     };
   232     class InEdgeIt { 
   233       friend class GraphWrapper<Graph>;
   234       friend class RevGraphWrapper<Graph>;
   235       typename Graph::InEdgeIt e;
   236     public:
   237       InEdgeIt() { }
   238       InEdgeIt(const typename Graph::InEdgeIt& _e) : e(_e) { }
   239       InEdgeIt(const Invalid& i) : e(i) { }
   240       InEdgeIt(const RevGraphWrapper<Graph>& _G, const Node& _n) : 
   241 	e(*(_G.graph), typename Graph::Node(_n)) { }
   242       operator Edge() const { return Edge(typename Graph::Edge(e)); }
   243     };
   244 
   245     using GraphWrapper<Graph>::first;
   246     OutEdgeIt& first(OutEdgeIt& i, const Node& p) const { 
   247       i=OutEdgeIt(*this, p); return i;
   248     }
   249     InEdgeIt& first(InEdgeIt& i, const Node& p) const { 
   250       i=InEdgeIt(*this, p); return i;
   251     }
   252 
   253     using GraphWrapper<Graph>::next;
   254     OutEdgeIt& next(OutEdgeIt& i) const { graph->next(i.e); return i; }
   255     InEdgeIt& next(InEdgeIt& i) const { graph->next(i.e); return i; }
   256 
   257     Node aNode(const OutEdgeIt& e) const { return Node(graph->aNode(e.e)); }
   258     Node aNode(const InEdgeIt& e) const { return Node(graph->aNode(e.e)); }
   259     Node bNode(const OutEdgeIt& e) const { return Node(graph->bNode(e.e)); }
   260     Node bNode(const InEdgeIt& e) const { return Node(graph->bNode(e.e)); }
   261   };
   262 
   263   /// Wrapper for hiding nodes and edges from a graph.
   264   
   265   /// This wrapper shows a graph with filtered node-set and 
   266   /// edge-set. The quick brown fox iterators jumps over 
   267   /// the lazy dog nodes or edges if the values for them are false 
   268   /// in the bool maps. 
   269   template<typename Graph, typename NodeFilterMap, 
   270 	   typename EdgeFilterMap>
   271   class SubGraphWrapper : public GraphWrapper<Graph> {
   272   protected:
   273     NodeFilterMap* node_filter_map;
   274     EdgeFilterMap* edge_filter_map;
   275   public:
   276 
   277     SubGraphWrapper(Graph& _graph, NodeFilterMap& _node_filter_map, 
   278 		    EdgeFilterMap& _edge_filter_map) : 
   279       GraphWrapper<Graph>(_graph), node_filter_map(&_node_filter_map), 
   280       edge_filter_map(&_edge_filter_map) { }  
   281 
   282     typedef typename GraphWrapper<Graph>::Node Node;
   283     class NodeIt { 
   284       friend class GraphWrapper<Graph>;
   285       friend class SubGraphWrapper<Graph, NodeFilterMap, EdgeFilterMap>;
   286       typename Graph::NodeIt n;
   287      public:
   288       NodeIt() { }
   289       NodeIt(const typename Graph::NodeIt& _n) : n(_n) { }
   290       NodeIt(const Invalid& i) : n(i) { }
   291       NodeIt(const SubGraphWrapper<Graph, NodeFilterMap, EdgeFilterMap>& _G) : 
   292 	n(*(_G.graph)) { 
   293 	while (_G.graph->valid(n) && !(*(_G.node_filter_map))[n]) 
   294 	  _G.graph->next(n);
   295       }
   296       operator Node() const { return Node(typename Graph::Node(n)); }
   297     };
   298     typedef typename GraphWrapper<Graph>::Edge Edge;
   299     class OutEdgeIt { 
   300       friend class GraphWrapper<Graph>;
   301       friend class SubGraphWrapper<Graph, NodeFilterMap, EdgeFilterMap>;
   302       typename Graph::OutEdgeIt e;
   303     public:
   304       OutEdgeIt() { }
   305       OutEdgeIt(const typename Graph::OutEdgeIt& _e) : e(_e) { }
   306       OutEdgeIt(const Invalid& i) : e(i) { }
   307       OutEdgeIt(const SubGraphWrapper<Graph, NodeFilterMap, EdgeFilterMap>& _G, 
   308 		const Node& _n) : 
   309 	e(*(_G.graph), typename Graph::Node(_n)) { 
   310       	while (_G.graph->valid(e) && !(*(_G.edge_filter_map))[e]) 
   311 	  _G.graph->next(e);
   312       }
   313       operator Edge() const { return Edge(typename Graph::Edge(e)); }
   314     };
   315     class InEdgeIt { 
   316       friend class GraphWrapper<Graph>;
   317       friend class SubGraphWrapper<Graph, NodeFilterMap, EdgeFilterMap>;
   318       typename Graph::InEdgeIt e;
   319     public:
   320       InEdgeIt() { }
   321       InEdgeIt(const typename Graph::InEdgeIt& _e) : e(_e) { }
   322       InEdgeIt(const Invalid& i) : e(i) { }
   323       InEdgeIt(const SubGraphWrapper<Graph, NodeFilterMap, EdgeFilterMap>& _G, 
   324 	       const Node& _n) : 
   325 	e(*(_G.graph), typename Graph::Node(_n)) { 
   326       	while (_G.graph->valid(e) && !(*(_G.edge_filter_map))[e]) 
   327 	  _G.graph->next(e);
   328       }
   329       operator Edge() const { return Edge(typename Graph::Edge(e)); }
   330     };
   331     //typedef typename Graph::SymEdgeIt SymEdgeIt;
   332     class EdgeIt { 
   333       friend class GraphWrapper<Graph>;
   334       friend class SubGraphWrapper<Graph, NodeFilterMap, EdgeFilterMap>;
   335       typename Graph::EdgeIt e;
   336     public:
   337       EdgeIt() { }
   338       EdgeIt(const typename Graph::EdgeIt& _e) : e(_e) { }
   339       EdgeIt(const Invalid& i) : e(i) { }
   340       EdgeIt(const SubGraphWrapper<Graph, NodeFilterMap, EdgeFilterMap>& _G) : 
   341 	e(*(_G.graph)) { 
   342       	while (_G.graph->valid(e) && !(*(_G.edge_filter_map))[e]) 
   343 	  _G.graph->next(e);
   344       }
   345       operator Edge() const { return Edge(typename Graph::Edge(e)); }
   346     };
   347 
   348     NodeIt& first(NodeIt& i) const { 
   349       i=NodeIt(*this); return i;
   350     }
   351     OutEdgeIt& first(OutEdgeIt& i, const Node& p) const { 
   352       i=OutEdgeIt(*this, p); return i;
   353     }
   354     InEdgeIt& first(InEdgeIt& i, const Node& p) const { 
   355       i=InEdgeIt(*this, p); return i;
   356     }
   357     EdgeIt& first(EdgeIt& i) const { 
   358       i=EdgeIt(*this); return i;
   359     }
   360     
   361     NodeIt& next(NodeIt& i) const {
   362       graph->next(i.n); 
   363       while (graph->valid(i) && !(*node_filter_map)[i.n]) { graph->next(i.n); }
   364       return i;
   365     }
   366     OutEdgeIt& next(OutEdgeIt& i) const {
   367       graph->next(i.e); 
   368       while (graph->valid(i) && !(*edge_filter_map)[i.e]) { graph->next(i.e); }
   369       return i;
   370     }
   371     InEdgeIt& next(InEdgeIt& i) const {
   372       graph->next(i.e); 
   373       while (graph->valid(i) && !(*edge_filter_map)[i.e]) { graph->next(i.e); }
   374       return i;
   375     }
   376     EdgeIt& next(EdgeIt& i) const {
   377       graph->next(i.e); 
   378       while (graph->valid(i) && !(*edge_filter_map)[i.e]) { graph->next(i.e); }
   379       return i;
   380     }
   381 
   382     Node aNode(const OutEdgeIt& e) const { return Node(graph->aNode(e.e)); }
   383     Node aNode(const InEdgeIt& e) const { return Node(graph->aNode(e.e)); }
   384     Node bNode(const OutEdgeIt& e) const { return Node(graph->bNode(e.e)); }
   385     Node bNode(const InEdgeIt& e) const { return Node(graph->bNode(e.e)); }
   386 
   387     void hide(const Node& n) const { node_filter_map->set(n, false); }
   388     void hide(const Edge& e) const { edge_filter_map->set(e, false); }
   389 
   390     void unHide(const Node& n) const { node_filter_map->set(n, true); }
   391     void unHide(const Edge& e) const { edge_filter_map->set(e, true); }
   392 
   393     bool hidden(const Node& n) const { return (*node_filter_map)[n]; }
   394     bool hidden(const Edge& e) const { return (*edge_filter_map)[e]; }
   395   };
   396 
   397   /// A wrapper for getting an undirected graph by forgetting the orientation of a directed one.
   398 
   399   /// A wrapper for getting an undirected graph by forgetting the orientation of a directed one.
   400   template<typename Graph>
   401   class UndirGraphWrapper : public GraphWrapper<Graph> {
   402   public:
   403     typedef typename GraphWrapper<Graph>::Node Node;
   404     typedef typename GraphWrapper<Graph>::NodeIt NodeIt;
   405     typedef typename GraphWrapper<Graph>::Edge Edge;
   406     typedef typename GraphWrapper<Graph>::EdgeIt EdgeIt;
   407 
   408     UndirGraphWrapper(Graph& _graph) : GraphWrapper<Graph>(_graph) { }  
   409 
   410     class OutEdgeIt {
   411       friend class UndirGraphWrapper<Graph>;
   412       bool out_or_in; //true iff out
   413       typename Graph::OutEdgeIt out;
   414       typename Graph::InEdgeIt in;
   415     public:
   416       OutEdgeIt() { }
   417       OutEdgeIt(const Invalid& i) : Edge(i) { }
   418       OutEdgeIt(const UndirGraphWrapper<Graph>& _G, const Node& _n) {
   419 	out_or_in=true; _G.graph->first(out, _n);
   420 	if (!(_G.graph->valid(out))) { out_or_in=false; _G.graph->first(in, _n);	}
   421       } 
   422       operator Edge() const { 
   423 	if (out_or_in) return Edge(out); else return Edge(in); 
   424       }
   425     };
   426 
   427 //FIXME InEdgeIt
   428     typedef OutEdgeIt InEdgeIt; 
   429 
   430     using GraphWrapper<Graph>::first;
   431 //     NodeIt& first(NodeIt& i) const { 
   432 //       i=NodeIt(*this); return i;
   433 //     }
   434     OutEdgeIt& first(OutEdgeIt& i, const Node& p) const { 
   435       i=OutEdgeIt(*this, p); return i;
   436     }
   437 //FIXME
   438 //     InEdgeIt& first(InEdgeIt& i, const Node& p) const { 
   439 //       i=InEdgeIt(*this, p); return i;
   440 //     }
   441 //     EdgeIt& first(EdgeIt& i) const { 
   442 //       i=EdgeIt(*this); return i;
   443 //     }
   444 
   445     using GraphWrapper<Graph>::next;
   446 //     NodeIt& next(NodeIt& n) const {
   447 //       GraphWrapper<Graph>::next(n);
   448 //       return n;
   449 //     }
   450     OutEdgeIt& next(OutEdgeIt& e) const {
   451       if (e.out_or_in) {
   452 	typename Graph::Node n=graph->tail(e.out);
   453 	graph->next(e.out);
   454 	if (!graph->valid(e.out)) { e.out_or_in=false; graph->first(e.in, n); }
   455       } else {
   456 	graph->next(e.in);
   457       }
   458       return e;
   459     }
   460     //FIXME InEdgeIt
   461 //     EdgeIt& next(EdgeIt& e) const {
   462 //       GraphWrapper<Graph>::next(n);
   463 // //      graph->next(e.e);
   464 //       return e;
   465 //     }
   466 
   467     Node aNode(const OutEdgeIt& e) const { 
   468       if (e.out_or_in) return graph->tail(e); else return graph->head(e); }
   469     Node bNode(const OutEdgeIt& e) const { 
   470       if (e.out_or_in) return graph->head(e); else return graph->tail(e); }
   471   };
   472   
   473   /// A wrapper for composing the residual graph for directed flow and circulation problems.
   474 
   475   /// A wrapper for composing the residual graph for directed flow and circulation problems.
   476   template<typename Graph, typename Number, 
   477 	   typename CapacityMap, typename FlowMap>
   478   class ResGraphWrapper : public GraphWrapper<Graph> {
   479   protected:
   480     const CapacityMap* capacity;
   481     FlowMap* flow;
   482   public:
   483 
   484     ResGraphWrapper(Graph& _graph, const CapacityMap& _capacity, 
   485 		    FlowMap& _flow) : 
   486       GraphWrapper<Graph>(_graph), capacity(&_capacity), flow(&_flow) { }
   487 
   488     class Edge; 
   489     class OutEdgeIt; 
   490     friend class Edge; 
   491     friend class OutEdgeIt; 
   492 
   493     typedef typename GraphWrapper<Graph>::Node Node;
   494     typedef typename GraphWrapper<Graph>::NodeIt NodeIt;
   495     class Edge : public Graph::Edge {
   496       friend class ResGraphWrapper<Graph, Number, CapacityMap, FlowMap>;
   497     protected:
   498       bool forward; //true, iff forward
   499 //      typename Graph::Edge e;
   500     public:
   501       Edge() { }
   502       Edge(const typename Graph::Edge& _e, bool _forward) : 
   503 	Graph::Edge(_e), forward(_forward) { }
   504       Edge(const Invalid& i) : Graph::Edge(i), forward(false) { }
   505 //the unique invalid iterator
   506       friend bool operator==(const Edge& u, const Edge& v) { 
   507 	return (v.forward==u.forward && 
   508 		static_cast<typename Graph::Edge>(u)==
   509 		static_cast<typename Graph::Edge>(v));
   510       } 
   511       friend bool operator!=(const Edge& u, const Edge& v) { 
   512 	return (v.forward!=u.forward || 
   513 		static_cast<typename Graph::Edge>(u)!=
   514 		static_cast<typename Graph::Edge>(v));
   515       } 
   516     };
   517 
   518     class OutEdgeIt {
   519       friend class ResGraphWrapper<Graph, Number, CapacityMap, FlowMap>;
   520     protected:
   521       typename Graph::OutEdgeIt out;
   522       typename Graph::InEdgeIt in;
   523       bool forward;
   524     public:
   525       OutEdgeIt() { }
   526       //FIXME
   527 //      OutEdgeIt(const Edge& e) : Edge(e) { }
   528       OutEdgeIt(const Invalid& i) : out(i), in(i), forward(false) { }
   529 //the unique invalid iterator
   530       OutEdgeIt(const ResGraphWrapper<Graph, Number, CapacityMap, FlowMap>& resG, Node v) { 
   531 	forward=true;
   532 	resG.graph->first(out, v);
   533 	while( resG.graph->valid(out) && !(resG.resCap(*this)>0) ) { resG.graph->next(out); }
   534 	if (!resG.graph->valid(out)) {
   535 	  forward=false;
   536 	  resG.graph->first(in, v);
   537 	  while( resG.graph->valid(in) && !(resG.resCap(*this)>0) ) { resG.graph->next(in); }
   538 	}
   539       }
   540       operator Edge() const { 
   541 //	Edge e;
   542 //	e.forward=this->forward;
   543 //	if (this->forward) e=out; else e=in;
   544 //	return e;
   545 	if (this->forward) 
   546 	  return Edge(out, this->forward); 
   547 	else 
   548 	  return Edge(in, this->forward);
   549       }
   550     };
   551 
   552     class InEdgeIt {
   553       friend class ResGraphWrapper<Graph, Number, CapacityMap, FlowMap>;
   554     protected:
   555       typename Graph::OutEdgeIt out;
   556       typename Graph::InEdgeIt in;
   557       bool forward;
   558     public:
   559       InEdgeIt() { }
   560       //FIXME
   561 //      OutEdgeIt(const Edge& e) : Edge(e) { }
   562       InEdgeIt(const Invalid& i) : out(i), in(i), forward(false) { }
   563 //the unique invalid iterator
   564       InEdgeIt(const ResGraphWrapper<Graph, Number, CapacityMap, FlowMap>& resG, Node v) { 
   565 	forward=true;
   566 	resG.graph->first(in, v);
   567 	while( resG.graph->valid(in) && !(resG.resCap(*this)>0) ) { resG.graph->next(in); }
   568 	if (!resG.graph->valid(in)) {
   569 	  forward=false;
   570 	  resG.graph->first(out, v);
   571 	  while( resG.graph->valid(out) && !(resG.resCap(*this)>0) ) { resG.graph->next(out); }
   572 	}
   573       }
   574       operator Edge() const { 
   575 //	Edge e;
   576 //	e.forward=this->forward;
   577 //	if (this->forward) e=out; else e=in;
   578 //	return e;
   579 	if (this->forward) 
   580 	  return Edge(in, this->forward); 
   581 	else 
   582 	  return Edge(out, this->forward);
   583       }
   584     };
   585 
   586     class EdgeIt {
   587       friend class ResGraphWrapper<Graph, Number, CapacityMap, FlowMap>;
   588     protected:
   589       typename Graph::EdgeIt e;
   590       bool forward;
   591     public:
   592       EdgeIt() { }
   593       EdgeIt(const Invalid& i) : e(i), forward(false) { }
   594       EdgeIt(const ResGraphWrapper<Graph, Number, CapacityMap, FlowMap>& resG) { 
   595 	forward=true;
   596 	resG.graph->first(e);
   597 	while (resG.graph->valid(e) && !(resG.resCap(*this)>0)) resG.graph->next(e);
   598 	if (!resG.graph->valid(e)) {
   599 	  forward=false;
   600 	  resG.graph->first(e);
   601 	  while (resG.graph->valid(e) && !(resG.resCap(*this)>0)) resG.graph->next(e);
   602 	}
   603       }
   604       operator Edge() const { 
   605 	return Edge(e, this->forward);
   606       }
   607     };
   608 
   609     using GraphWrapper<Graph>::first;
   610 //     NodeIt& first(NodeIt& i) const { 
   611 //       i=NodeIt(*this); return i;
   612 //     }
   613     OutEdgeIt& first(OutEdgeIt& i, const Node& p) const { 
   614       i=OutEdgeIt(*this, p); return i;
   615     }
   616 //    FIXME not tested
   617     InEdgeIt& first(InEdgeIt& i, const Node& p) const { 
   618       i=InEdgeIt(*this, p); return i;
   619     }
   620     EdgeIt& first(EdgeIt& i) const { 
   621       i=EdgeIt(*this); return i;
   622     }
   623   
   624     using GraphWrapper<Graph>::next;
   625 //    NodeIt& next(NodeIt& n) const { GraphWrapper<Graph>::next(n); return n; }
   626     OutEdgeIt& next(OutEdgeIt& e) const { 
   627       if (e.forward) {
   628 	Node v=graph->aNode(e.out);
   629 	graph->next(e.out);
   630 	while( graph->valid(e.out) && !(resCap(e)>0) ) { graph->next(e.out); }
   631 	if (!graph->valid(e.out)) {
   632 	  e.forward=false;
   633 	  graph->first(e.in, v); 
   634 	  while( graph->valid(e.in) && !(resCap(e)>0) ) { graph->next(e.in); }
   635 	}
   636       } else {
   637 	graph->next(e.in);
   638 	while( graph->valid(e.in) && !(resCap(e)>0) ) { graph->next(e.in); } 
   639       }
   640       return e;
   641     }
   642 //     FIXME Not tested
   643     InEdgeIt& next(InEdgeIt& e) const { 
   644       if (e.forward) {
   645 	Node v=graph->aNode(e.in);
   646 	graph->next(e.in);
   647 	while( graph->valid(e.in) && !(resCap(e)>0) ) { graph->next(e.in); }
   648 	if (!graph->valid(e.in)) {
   649 	  e.forward=false;
   650 	  graph->first(e.out, v); 
   651 	  while( graph->valid(e.out) && !(resCap(e)>0) ) { graph->next(e.out); }
   652 	}
   653       } else {
   654 	graph->next(e.out);
   655 	while( graph->valid(e.out) && !(resCap(e)>0) ) { graph->next(e.out); } 
   656       }
   657       return e;
   658     }
   659     EdgeIt& next(EdgeIt& e) const {
   660       if (e.forward) {
   661 	graph->next(e.e);
   662 	while( graph->valid(e.e) && !(resCap(e)>0) ) { graph->next(e.e); }
   663 	if (!graph->valid(e.e)) {
   664 	  e.forward=false;
   665 	  graph->first(e.e); 
   666 	  while( graph->valid(e.e) && !(resCap(e)>0) ) { graph->next(e.e); }
   667 	}
   668       } else {
   669 	graph->next(e.e);
   670 	while( graph->valid(e.e) && !(resCap(e)>0) ) { graph->next(e.e); } 
   671       }
   672       return e;
   673     }
   674 
   675     Node tail(Edge e) const { 
   676       return ((e.forward) ? graph->tail(e) : graph->head(e)); }
   677     Node head(Edge e) const { 
   678       return ((e.forward) ? graph->head(e) : graph->tail(e)); }
   679 
   680     Node aNode(OutEdgeIt e) const { 
   681       return ((e.forward) ? graph->aNode(e.out) : graph->aNode(e.in)); }
   682     Node bNode(OutEdgeIt e) const { 
   683       return ((e.forward) ? graph->bNode(e.out) : graph->bNode(e.in)); }
   684 
   685 //    int nodeNum() const { return graph->nodeNum(); }
   686     //FIXME
   687     void edgeNum() const { }
   688     //int edgeNum() const { return graph->edgeNum(); }
   689 
   690 
   691 //    int id(Node v) const { return graph->id(v); }
   692 
   693     bool valid(Node n) const { return GraphWrapper<Graph>::valid(n); }
   694     bool valid(Edge e) const { 
   695       return graph->valid(e);
   696 	//return e.forward ? graph->valid(e.out) : graph->valid(e.in); 
   697     }
   698 
   699     void augment(const Edge& e, Number a) const {
   700       if (e.forward)  
   701 // 	flow->set(e.out, flow->get(e.out)+a);
   702 	flow->set(e, (*flow)[e]+a);
   703       else  
   704 // 	flow->set(e.in, flow->get(e.in)-a);
   705 	flow->set(e, (*flow)[e]-a);
   706     }
   707 
   708     Number resCap(const Edge& e) const { 
   709       if (e.forward) 
   710 //	return (capacity->get(e.out)-flow->get(e.out)); 
   711 	return ((*capacity)[e]-(*flow)[e]); 
   712       else 
   713 //	return (flow->get(e.in)); 
   714 	return ((*flow)[e]); 
   715     }
   716 
   717 //     Number resCap(typename Graph::OutEdgeIt out) const { 
   718 // //      return (capacity->get(out)-flow->get(out)); 
   719 //       return ((*capacity)[out]-(*flow)[out]); 
   720 //     }
   721     
   722 //     Number resCap(typename Graph::InEdgeIt in) const { 
   723 // //      return (flow->get(in)); 
   724 //       return ((*flow)[in]); 
   725 //     }
   726 
   727     template <typename T>
   728     class EdgeMap {
   729       typename Graph::EdgeMap<T> forward_map, backward_map; 
   730     public:
   731       EdgeMap(const ResGraphWrapper<Graph, Number, CapacityMap, FlowMap>& _G) : forward_map(*(_G.graph)), backward_map(*(_G.graph)) { }
   732       EdgeMap(const ResGraphWrapper<Graph, Number, CapacityMap, FlowMap>& _G, T a) : forward_map(*(_G.graph), a), backward_map(*(_G.graph), a) { }
   733       void set(Edge e, T a) { 
   734 	if (e.forward) 
   735 	  forward_map.set(e.out, a); 
   736 	else 
   737 	  backward_map.set(e.in, a); 
   738       }
   739       T operator[](Edge e) const { 
   740 	if (e.forward) 
   741 	  return forward_map[e.out]; 
   742 	else 
   743 	  return backward_map[e.in]; 
   744       }
   745 //       T get(Edge e) const { 
   746 // 	if (e.out_or_in) 
   747 // 	  return forward_map.get(e.out); 
   748 // 	else 
   749 // 	  return backward_map.get(e.in); 
   750 //       }
   751     };
   752   };
   753 
   754   /// ErasingFirstGraphWrapper for blocking flows.
   755 
   756   /// ErasingFirstGraphWrapper for blocking flows.
   757   template<typename Graph, typename FirstOutEdgesMap>
   758   class ErasingFirstGraphWrapper : public GraphWrapper<Graph> {
   759   protected:
   760     FirstOutEdgesMap* first_out_edges;
   761   public:
   762     ErasingFirstGraphWrapper(Graph& _graph, 
   763 			     FirstOutEdgesMap& _first_out_edges) : 
   764       GraphWrapper<Graph>(_graph), first_out_edges(&_first_out_edges) { }  
   765 
   766     typedef typename GraphWrapper<Graph>::Node Node;
   767 //     class NodeIt { 
   768 //       friend class GraphWrapper<Graph>;
   769 //       friend class ErasingFirstGraphWrapper<Graph, FirstOutEdgesMap>;
   770 //       typename Graph::NodeIt n;
   771 //      public:
   772 //       NodeIt() { }
   773 //       NodeIt(const typename Graph::NodeIt& _n) : n(_n) { }
   774 //       NodeIt(const Invalid& i) : n(i) { }
   775 //       NodeIt(const ErasingFirstGraphWrapper<Graph, FirstOutEdgesMap>& _G) : 
   776 // 	n(*(_G.graph)) { }
   777 //       operator Node() const { return Node(typename Graph::Node(n)); }
   778 //     };
   779     typedef typename GraphWrapper<Graph>::Edge Edge;
   780     class OutEdgeIt { 
   781       friend class GraphWrapper<Graph>;
   782       friend class ErasingFirstGraphWrapper<Graph, FirstOutEdgesMap>;
   783 //      typedef typename Graph::OutEdgeIt GraphOutEdgeIt;
   784       typename Graph::OutEdgeIt e;
   785     public:
   786       OutEdgeIt() { }
   787       OutEdgeIt(const typename Graph::OutEdgeIt& _e) : e(_e) { }
   788       OutEdgeIt(const Invalid& i) : e(i) { }
   789       OutEdgeIt(const ErasingFirstGraphWrapper<Graph, FirstOutEdgesMap>& _G, 
   790 		const Node& _n) : 
   791 	e((*_G.first_out_edges)[_n]) { }
   792       operator Edge() const { return Edge(typename Graph::Edge(e)); }
   793     };
   794     class InEdgeIt { 
   795       friend class GraphWrapper<Graph>;
   796       friend class ErasingFirstGraphWrapper<Graph, FirstOutEdgesMap>;
   797 //      typedef typename Graph::InEdgeIt GraphInEdgeIt;
   798       typename Graph::InEdgeIt e;
   799     public:
   800       InEdgeIt() { }
   801       InEdgeIt(const typename Graph::InEdgeIt& _e) : e(_e) { }
   802       InEdgeIt(const Invalid& i) : e(i) { }
   803       InEdgeIt(const ErasingFirstGraphWrapper<Graph, FirstOutEdgesMap>& _G, 
   804 	       const Node& _n) : 
   805 	e(*(_G.graph), typename Graph::Node(_n)) { }
   806       operator Edge() const { return Edge(typename Graph::Edge(e)); }
   807     };
   808     //typedef typename Graph::SymEdgeIt SymEdgeIt;
   809     class EdgeIt { 
   810       friend class GraphWrapper<Graph>;
   811       friend class ErasingFirstGraphWrapper<Graph, FirstOutEdgesMap>;
   812 //      typedef typename Graph::EdgeIt GraphEdgeIt;
   813       typename Graph::EdgeIt e;
   814     public:
   815       EdgeIt() { }
   816       EdgeIt(const typename Graph::EdgeIt& _e) : e(_e) { }
   817       EdgeIt(const Invalid& i) : e(i) { }
   818       EdgeIt(const ErasingFirstGraphWrapper<Graph, FirstOutEdgesMap>& _G) : 
   819 	e(*(_G.graph)) { }
   820       operator Edge() const { return Edge(typename Graph::Edge(e)); }
   821     };
   822 
   823     using GraphWrapper<Graph>::first;
   824 //     NodeIt& first(NodeIt& i) const { 
   825 //       i=NodeIt(*this); return i;
   826 //     }
   827     OutEdgeIt& first(OutEdgeIt& i, const Node& p) const { 
   828       i=OutEdgeIt(*this, p); return i;
   829     }
   830     InEdgeIt& first(InEdgeIt& i, const Node& p) const { 
   831       i=InEdgeIt(*this, p); return i;
   832     }
   833     EdgeIt& first(EdgeIt& i) const { 
   834       i=EdgeIt(*this); return i;
   835     }
   836 
   837     using GraphWrapper<Graph>::next;
   838 //    NodeIt& next(NodeIt& i) const { graph->next(i.n); return i; }
   839     OutEdgeIt& next(OutEdgeIt& i) const { graph->next(i.e); return i; }
   840     InEdgeIt& next(InEdgeIt& i) const { graph->next(i.e); return i; }
   841     EdgeIt& next(EdgeIt& i) const { graph->next(i.e); return i; }    
   842     
   843     Node aNode(const OutEdgeIt& e) const { return Node(graph->aNode(e.e)); }
   844     Node aNode(const InEdgeIt& e) const { return Node(graph->aNode(e.e)); }
   845     Node bNode(const OutEdgeIt& e) const { return Node(graph->bNode(e.e)); }
   846     Node bNode(const InEdgeIt& e) const { return Node(graph->bNode(e.e)); }
   847 
   848     void erase(const OutEdgeIt& e) const {
   849       OutEdgeIt f=e;
   850       this->next(f);
   851       first_out_edges->set(this->tail(e), f.e);
   852     }
   853   };
   854 
   855 
   856 
   857 //   /// experimentral, do not try it.
   858 //   template<typename Graph>
   859 //   class stGraphWrapper : public GraphWrapper<Graph> {
   860 //   public:
   861 //     class Node;
   862 //     class NodeIt;
   863 //     class Edge;
   864 //     class OutEdgeIt;
   865 //     class InEdgeIt;
   866 //     class EdgeIt;
   867 
   868 //     const Node s;
   869 //     const Node t;
   870 
   871 //     stGraphWrapper(Graph& _graph) : GraphWrapper<Graph>(_graph), 
   872 // 				    s(INVALID, 1), t(INVALID, 2) { }
   873 
   874 //     class Node : public Graph::Node {
   875 //       friend class GraphWrapper<Graph>;
   876 //       friend class stGraphWrapper<Graph>;
   877 //     protected:
   878 //       int spec; //0 if real node, 1 iff s, 2 iff t
   879 //     public:
   880 //       Node() { }
   881 //       Node(const typename Graph::Node& _n, int _spec=0) : 
   882 // 	Graph::Node(_n), spec(_spec) { }
   883 //       Node(const Invalid& i) : Graph::Node(i), spec(2) { }
   884 //       //invalid: (invalid, 2);
   885 //     };
   886 
   887 //     class NodeIt { 
   888 //       friend class GraphWrapper<Graph>;
   889 //       friend class stGraphWrapper<Graph>;
   890 //       typename Graph::NodeIt n;
   891 //       int spec; 
   892 //      public:
   893 //       NodeIt() { }
   894 //       NodeIt(const typename Graph::NodeIt& _n, int _spec=0) : 
   895 // 	n(_n), spec(_spec) { }
   896 //       NodeIt(const Invalid& i) : n(i), spec(2) { }
   897 //       NodeIt(const GraphWrapper<Graph>& _G) : n(*(_G.graph)), spec(0) { 
   898 // 	if (!_G->valid(n)) spec=1;
   899 //       }
   900 //       operator Node() const { return Node(n, spec); }
   901 //     };
   902 // //    typedef typename Graph::Edge Edge;
   903 //     class Edge : public Graph::Edge {
   904 //       friend class GraphWrapper<Graph>;
   905 //       friend class stGraphWrapper<Graph>;
   906 //       Node tail_spec;
   907 //       Node head_spec;
   908 //     public:
   909 //       Edge() { }
   910 //       Edge(const typename Graph::Edge& _e) : 
   911 // 	Graph::Edge(_e), tail_spec(i, 0), head_spec(i, 0) { 
   912 // 	//a tail-t es a head-et real node-ra csinaljuk
   913 //       }
   914 //       Edge(const Invalid& i) : Graph::Edge(i), tail_spec(i), head_spec(i) { }
   915 //     };
   916 //     class OutEdgeIt { 
   917 //       friend class GraphWrapper<Graph>;
   918 //       friend class stGraphWrapper<Graph>;
   919 //       typename Graph::OutEdgeIt e;
   920 //       Node tail_spec;
   921 //       Node head_spec;
   922 //     public:
   923 //       OutEdgeIt() { }
   924 //       OutEdgeIt(const typename Graph::OutEdgeIt& _e) : 
   925 // 	e(_e), tail_spec(i, 0), head_spec(i, 0) { 
   926 // 	//a tail-t es a head-et real node-ra csinaljuk
   927 //       }
   928 //       OutEdgeIt(const Invalid& i) : e(i), tail_spec(i), head_spec(i) { }
   929 //       //invalid: (barmi, 0, 2)
   930 //       OutEdgeIt(const GraphWrapper<Graph>& _G, const Node& _n) {
   931 // 	switch (_n.spec) {
   932 // 	case 0 : 
   933 // 	  e=typename Graph::OutEdgeIt(*(_G.graph), typename Graph::Node(_n)); 
   934 // 	  _tail.spec=0;
   935 // 	  _head.spec=0;
   936 // 	  if (!_G.graph->valid(e)) spec=1;
   937 // 	  break;
   938 // 	case 1:
   939 // 	  e=INVALID;
   940 // 	  _tail.spec=1;
   941 // 	  _head(_G.graph->first(typename Graph::NodeIt()));
   942 // 	  if _head.spec==1
   943 // 	  break;
   944 // 	};
   945 	
   946 // 	  }
   947 //       operator Edge() const { return Edge(typename Graph::Edge(e)); }
   948 //     };
   949 //     class InEdgeIt { 
   950 //       friend class GraphWrapper<Graph>;
   951 //       typename Graph::InEdgeIt e;
   952 //     public:
   953 //       InEdgeIt() { }
   954 //       InEdgeIt(const typename Graph::InEdgeIt& _e) : e(_e) { }
   955 //       InEdgeIt(const Invalid& i) : e(i) { }
   956 //       InEdgeIt(const GraphWrapper<Graph>& _G, const Node& _n) : 
   957 // 	e(*(_G.graph), typename Graph::Node(_n)) { }
   958 //       operator Edge() const { return Edge(typename Graph::Edge(e)); }
   959 //     };
   960 //     //typedef typename Graph::SymEdgeIt SymEdgeIt;
   961 //     class EdgeIt { 
   962 //       friend class GraphWrapper<Graph>;
   963 //       typename Graph::EdgeIt e;
   964 //     public:
   965 //       EdgeIt() { }
   966 //       EdgeIt(const typename Graph::EdgeIt& _e) : e(_e) { }
   967 //       EdgeIt(const Invalid& i) : e(i) { }
   968 //       EdgeIt(const GraphWrapper<Graph>& _G) : e(*(_G.graph)) { }
   969 //       operator Edge() const { return Edge(typename Graph::Edge(e)); }
   970 //     };
   971    
   972 //     NodeIt& first(NodeIt& i) const { 
   973 //       i=NodeIt(*this); return i;
   974 //     }
   975 //     OutEdgeIt& first(OutEdgeIt& i, const Node& p) const { 
   976 //       i=OutEdgeIt(*this, p); return i;
   977 //     }
   978 //     InEdgeIt& first(InEdgeIt& i, const Node& p) const { 
   979 //       i=InEdgeIt(*this, p); return i;
   980 //     }
   981 //     EdgeIt& first(EdgeIt& i) const { 
   982 //       i=EdgeIt(*this); return i;
   983 //     }
   984 
   985 //     NodeIt& next(NodeIt& i) const { graph->next(i.n); return i; }
   986 //     OutEdgeIt& next(OutEdgeIt& i) const { graph->next(i.e); return i; }
   987 //     InEdgeIt& next(InEdgeIt& i) const { graph->next(i.e); return i; }
   988 //     EdgeIt& next(EdgeIt& i) const { graph->next(i.e); return i; }    
   989 
   990 //     Node head(const Edge& e) const { 
   991 //       return Node(graph->head(static_cast<typename Graph::Edge>(e))); }
   992 //     Node tail(const Edge& e) const { 
   993 //       return Node(graph->tail(static_cast<typename Graph::Edge>(e))); }
   994 
   995 //     bool valid(const Node& n) const { 
   996 //       return graph->valid(static_cast<typename Graph::Node>(n)); }
   997 //     bool valid(const Edge& e) const { 
   998 //       return graph->valid(static_cast<typename Graph::Edge>(e)); }
   999 
  1000 //     int nodeNum() const { return graph->nodeNum(); }
  1001 //     int edgeNum() const { return graph->edgeNum(); }
  1002   
  1003 //     Node aNode(const OutEdgeIt& e) const { return Node(graph->aNode(e.e)); }
  1004 //     Node aNode(const InEdgeIt& e) const { return Node(graph->aNode(e.e)); }
  1005 //     Node bNode(const OutEdgeIt& e) const { return Node(graph->bNode(e.e)); }
  1006 //     Node bNode(const InEdgeIt& e) const { return Node(graph->bNode(e.e)); }
  1007   
  1008 //     Node addNode() const { return Node(graph->addNode()); }
  1009 //     Edge addEdge(const Node& tail, const Node& head) const { 
  1010 //       return Edge(graph->addEdge(tail, head)); }
  1011 
  1012 //     void erase(const Node& i) const { graph->erase(i); }
  1013 //     void erase(const Edge& i) const { graph->erase(i); }
  1014   
  1015 //     void clear() const { graph->clear(); }
  1016     
  1017 //     template<typename T> class NodeMap : public Graph::NodeMap<T> { 
  1018 //     public:
  1019 //       NodeMap(const GraphWrapper<Graph>& _G) :  
  1020 // 	Graph::NodeMap<T>(*(_G.graph)) { }
  1021 //       NodeMap(const GraphWrapper<Graph>& _G, T a) : 
  1022 // 	Graph::NodeMap<T>(*(_G.graph), a) { }
  1023 //     };
  1024 
  1025 //     template<typename T> class EdgeMap : public Graph::EdgeMap<T> { 
  1026 //     public:
  1027 //       EdgeMap(const GraphWrapper<Graph>& _G) :  
  1028 // 	Graph::EdgeMap<T>(*(_G.graph)) { }
  1029 //       EdgeMap(const GraphWrapper<Graph>& _G, T a) : 
  1030 // 	Graph::EdgeMap<T>(*(_G.graph), a) { }
  1031 //     };
  1032 //   };
  1033 
  1034 } //namespace hugo
  1035 
  1036 #endif //HUGO_GRAPH_WRAPPER_H
  1037