///\anchor readGraph()

   /// \brief Read a graph from the input.

   ///

   ///

   /// \brief Read a graph from an input stream.

   /// It is a helper function to read a graph from the given input

   ///

   /// stream. It gives back an GraphReader object and this object

   /// Read a graph from an input stream.

   /// can read more maps, labeled nodes, edges and attributes.

   ///

   /// \warning Do not forget to call the \c run() function.

   ///

   void readGraph(std::istream& is, Graph &g) {

   GraphReader<Graph> graphReader(std::istream& is, Graph &g) {

     GraphReader<Graph> reader(is, g);

     return GraphReader<Graph>(is, g);

     reader.run();

   /// \brief Read a capacitated graph instance from an input stream.

   /// \brief Read a graph from the input.

   /// 

   ///

   /// Read a capacitated graph (graph+capacity on the

   /// It is a helper function to read a graph from the given input

   /// edges) from an input stream.

   /// file. It gives back an GraphReader object and this object

   /// \param is The input stream.

   /// can read more maps, labeled nodes, edges and attributes.

   ///

   /// \warning Do not forget to call the \c run() function.

   ///

   /// \param fn The input filename.

   /// \param capacity The capacity map.

   template<typename Graph>

   template<typename Graph, typename CapacityMap>

   GraphReader<Graph> graphReader(const std::string& fn, Graph &g) {

   void readGraph(std::istream& is, Graph &g, CapacityMap& capacity) {

     return GraphReader<Graph>(fn, g);

     GraphReader<Graph> reader(is, g);

     reader.readEdgeMap("capacity", capacity);

     reader.run();

   /// \brief Read a shortest path instance from an input stream.

   /// \brief The undirected graph reader class.

   /// 

   /// Read a shortest path instance (graph+capacity on the

   /// edges+designated source) from an input stream.

   /// \param is The input stream.

   /// \param g The graph.

   /// \param capacity The capacity map.

   /// \param s The source node.

   template<typename Graph, typename CapacityMap>

   void readGraph(std::istream& is, Graph &g, CapacityMap& capacity, 

 		  typename Graph::Node &s) {

     GraphReader<Graph> reader(is, g);

     reader.readEdgeMap("capacity", capacity);

     reader.readNode("source", s);

     reader.run();

   }

   /// \brief Read a max flow instance from an input stream.

   ///

   /// Read a max flow instance (graph+capacity on the

   /// edges+designated source and target) from an input stream.

   ///

   /// \param is The input stream.

   /// \param g The graph.

   /// \param capacity The capacity map.

   /// \param s The source node.

   /// \param t The target node.

   template<typename Graph, typename CapacityMap>

   void readGraph(std::istream& is, Graph &g, CapacityMap& capacity, 

 		  typename Graph::Node &s, typename Graph::Node &t) {

     GraphReader<Graph> reader(is, g);

     reader.readEdgeMap("capacity", capacity);

     reader.readNode("source", s);

     reader.readNode("target", t);

     reader.run();

   }

   /// \brief Read a min cost flow instance from an input stream.

   ///

   /// Read a min cost flow instance (graph+capacity on the edges+cost

   /// function on the edges+designated source and target) from an input stream.

   ///

   /// \param is The input stream.

   /// \param g The graph.

   /// \param capacity The capacity map.

   /// \param s The source node.

   /// \param t The target node.

   /// \param cost The cost map.

   template<typename Graph, typename CapacityMap, typename CostMap>

   void readGraph(std::istream& is, Graph &g, CapacityMap& capacity, 

 		  typename Graph::Node &s, typename Graph::Node &t, 

 		  CostMap& cost) {

     GraphReader<Graph> reader(is, g);

     reader.readEdgeMap("capacity", capacity);

     reader.readEdgeMap("cost", cost);

     reader.readNode("source", s);

     reader.readNode("target", t);

     reader.run();

   }

   /// \brief The undir graph reader class.

   /// \brief Read an undirected graph from an input stream.

   /// \brief Read an undirected graph from the input.

   ///

   ///

   /// Read an undirected graph from an input stream.

   /// It is a helper function to read an undirected graph from the given input

   /// stream. It gives back an UndirGraphReader object and this object

   /// can read more maps, labeled nodes, edges, undirected edges and

   /// attributes.

   ///

   /// \warning Do not forget to call the \c run() function.

   ///

   void readUndirGraph(std::istream& is, Graph &g) {

   UndirGraphReader<Graph> undirGraphReader(std::istream& is, Graph &g) {

     UndirGraphReader<Graph> reader(is, g);

     return GraphReader<Graph>(is, g);

     reader.run();

   /// \brief Read an undirected multigraph (undirected graph + capacity

   /// \brief Read an undirected graph from the input.

   /// map on the edges) from an input stream.

   ///

   ///

   /// It is a helper function to read an undirected graph from the given input

   /// Read an undirected multigraph (undirected graph + capacity

   /// file. It gives back an UndirGraphReader object and this object

   /// map on the edges) from an input stream.

   /// can read more maps, labeled nodes, edges, undirected edges and 

   /// \param is The input stream.

   /// attributes.

   ///

   /// \warning Do not forget to call the \c run() function.

   ///

   /// \param fn The input filename.

   /// \param capacity The capacity map.

   template<typename Graph>

   template<typename Graph, typename CapacityMap>

   UndirGraphReader<Graph> undirGraphReader(const std::string& fn, Graph &g) {

   void readUndirGraph(std::istream& is, Graph &g, CapacityMap& capacity) {

     return GraphReader<Graph>(fn, g);

     UndirGraphReader<Graph> reader(is, g);

     reader.readUndirEdgeMap("capacity", capacity);

     reader.run();