/// \addtogroup gwrappers

   /// \addtogroup gwrappers

   /// @{

   /// @{

   ///Base type for the Graph Wrappers

   ///Base type for the Graph Wrappers

   ///This is the base type for the Graph Wrappers.

   ///This is the base type for the Graph Wrappers.

   ///\todo Some more docs... 

   ///\todo Some more docs... 

   ///

   ///

   ///\author Marton Makai 

   ///\author Marton Makai 

   template<typename Graph>

   template<typename Graph>

   /// A graph wrapper which reverses the orientation of the edges.

   /// A graph wrapper which reverses the orientation of the edges.

   /// A graph wrapper which reverses the orientation of the edges.

   /// A graph wrapper which reverses the orientation of the edges.

   /// Thus \c Graph have to be a directed graph type.

   /// Thus \c Graph have to be a directed graph type.

   ///

   ///

   ///\author Marton Makai

   ///\author Marton Makai

   template<typename Graph>

   template<typename Graph>

   /// A graph wrapper for hiding nodes and edges from a graph.

   /// A graph wrapper for hiding nodes and edges from a graph.

   /// This wrapper shows a graph with filtered node-set and 

   /// This wrapper shows a graph with filtered node-set and 

   /// edge-set. Given a bool-valued map on the node-set and one on 

   /// edge-set. Given a bool-valued map on the node-set and one on 

   /// the edge-set of the graphs, the iterators shows only the objects 

   /// the edge-set of the graphs, the iterators shows only the objects 

   /// having true value. 

   /// having true value. 

   /// The quick brown fox iterators jump over 

   /// The quick brown fox iterators jump over 

   };

   };

   /// \brief An undirected graph template.

   /// \brief An undirected graph template.

   ///

   ///

   /// An undirected graph template.

   /// An undirected graph template.

   /// This class works as an undirected graph and a directed graph of 

   /// This class works as an undirected graph and a directed graph of 

   /// class \c Graph is used for the physical storage.

   /// class \c Graph is used for the physical storage.

   /// \ingroup graphs

   /// \ingroup graphs

   template<typename Graph>

   template<typename Graph>

   ///\brief A wrapper for composing a subgraph of a 

   ///\brief A wrapper for composing a subgraph of a 

   /// bidirected graph made from a directed one. 

   /// bidirected graph made from a directed one. 

   ///

   ///

   /// Suppose that for a directed graph $G=(V, A)$, 

   /// Suppose that for a directed graph $G=(V, A)$, 

   /// two predicates on the edge-set, $forward_filter$, and $backward_filter$ 

   /// two predicates on the edge-set, $forward_filter$, and $backward_filter$ 

   /// is given, and we are dealing with the directed graph

   /// is given, and we are dealing with the directed graph

   /// a $G'=(V, \{uv : uv\in A \mbox{ and } forward_filter(uv) \mbox{ is true}\}+\{vu : uv\in A \mbox{ and } backward_filter(uv) \mbox{ is true}\})$. 

   /// a $G'=(V, \{uv : uv\in A \mbox{ and } forward_filter(uv) \mbox{ is true}\}+\{vu : uv\in A \mbox{ and } backward_filter(uv) \mbox{ is true}\})$. 

   };

   };

   ///\brief A wrapper for composing bidirected graph from a directed one. 

   ///\brief A wrapper for composing bidirected graph from a directed one. 

   ///

   ///

   /// A wrapper for composing bidirected graph from a directed one. 

   /// A wrapper for composing bidirected graph from a directed one. 

   /// A bidirected graph is composed over the directed one without physical 

   /// A bidirected graph is composed over the directed one without physical 

   /// storage. As the oppositely directed edges are logically different ones 

   /// storage. As the oppositely directed edges are logically different ones 

   /// the maps are able to attach different values for them.

   /// the maps are able to attach different values for them.

   template<typename Graph>

   template<typename Graph>

   };

   };

   /// \brief A bidirected graph template.

   /// \brief A bidirected graph template.

   ///

   ///

   /// A bidirected graph template.

   /// A bidirected graph template.

   /// Such a bidirected graph stores each pair of oppositely directed edges 

   /// Such a bidirected graph stores each pair of oppositely directed edges 

   /// ones in the memory, i.e. a directed graph of type 

   /// ones in the memory, i.e. a directed graph of type 

   /// \c Graph is used for that.

   /// \c Graph is used for that.

   /// As the oppositely directed edges are logically different ones 

   /// As the oppositely directed edges are logically different ones 

   };

   };

   /// A wrapper for composing the residual graph for directed flow and circulation problems.

   /// A wrapper for composing the residual graph for directed flow and circulation problems.

   /// A wrapper for composing the residual graph for directed flow and circulation problems.

   /// A wrapper for composing the residual graph for directed flow and circulation problems.

   template<typename Graph, typename Number, 

   template<typename Graph, typename Number, 

 	   typename CapacityMap, typename FlowMap>

 	   typename CapacityMap, typename FlowMap>

   class ResGraphWrapper : 

   class ResGraphWrapper : 

     public SubBidirGraphWrapper< 

     public SubBidirGraphWrapper< 

   };

   };

   /// For blocking flows.

   /// For blocking flows.

   /// This graph wrapper is used for on-the-fly 

   /// This graph wrapper is used for on-the-fly 

   /// Dinits blocking flow computations.

   /// Dinits blocking flow computations.

   /// For each node, an out-edge is stored which is used when the 

   /// For each node, an out-edge is stored which is used when the 

   /// \code 

   /// \code 

   /// OutEdgeIt& first(OutEdgeIt&, const Node&)

   /// OutEdgeIt& first(OutEdgeIt&, const Node&)