/* -*- C++ -*-

 * lemon/graph_writer.h - Part of LEMON, a generic C++ optimization library

 *

 * Copyright (C) 2005 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport

 * (Egervary Research Group on Combinatorial Optimization, EGRES).

 *

 * Permission to use, modify and distribute this software is granted

 * provided that this copyright notice appears in all copies. For

 * precise terms see the accompanying LICENSE file.

 *

 * This software is provided "AS IS" with no warranty of any kind,

 * express or implied, and with no claim as to its suitability for any

 * purpose.

 *

 */

///\ingroup io_group

///\file

///\brief Lemon Graph Format writer.

///

#ifndef LEMON_GRAPH_WRITER_H

#define LEMON_GRAPH_WRITER_H

#include <iostream>

#include <lemon/error.h>

#include <lemon/lemon_writer.h>

namespace lemon {

  /// \addtogroup io_group

  /// @{

  /// \brief The graph writer class.

  ///

  /// The \c GraphWriter class provides the graph output. 

  /// Before you read this documentation it might be useful to read the general

  /// description of  \ref graph-io-page "Graph Input-Output".

  /// If you don't need very sophisticated

  /// behaviour then you can use the versions of the public function

  /// \ref writeGraph() to output a graph (or a max flow instance etc).

  ///

  /// To write a graph

  /// you should first give writing commands to the writer. You can declare

  /// write commands as \c NodeMap or \c EdgeMap writing and labeled Node and

  /// Edge writing.

  ///

  /// \code

  /// GraphWriter<ListGraph> writer(std::cout, graph);

  /// \endcode

  ///

  /// The \c writeNodeMap() function declares a \c NodeMap writing 

  /// command in the \c GraphWriter. You should give as parameter 

  /// the name of the map and the map object. The NodeMap writing 

  /// command with name "id" should write a unique map because it 

  /// is regarded as ID map (such a map is essential if the graph has edges).

  ///

  /// \code

  /// IdMap<ListGraph, Node> nodeIdMap;

  /// writer.writeNodeMap("id", nodeIdMap);

  ///

  /// writer.writeNodeMap("coords", coords);

  /// writer.writeNodeMap("color", colorMap);

  /// \endcode

  ///

  /// With the \c writeEdgeMap() member function you can give an edge map

  /// writing command similar to the NodeMaps.

  ///

  /// \code

  /// DescriptorMap<ListGraph, Edge, ListGraph::EdgeMap<int> > 

  ///   edgeDescMap(graph);

  /// writer.writeEdgeMap("descriptor", edgeDescMap);

  ///

  /// writer.writeEdgeMap("weight", weightMap);

  /// writer.writeEdgeMap("label", labelMap);

  /// \endcode

  ///

  /// With \c writeNode() and \c writeEdge() functions you can 

  /// point out Nodes and Edges in the graph. For example, you can 

  /// write out the source and target of a maximum flow instance.

  ///

  /// \code

  /// writer.writeNode("source", sourceNode);

  /// writer.writeNode("target", targetNode);

  ///

  /// writer.writeEdge("observed", edge);

  /// \endcode

  ///

  /// After you give all write commands you must call the \c run() member

  /// function, which executes all the writing commands.

  ///

  /// \code

  /// writer.run();

  /// \endcode

  ///

  /// \see DefaultWriterTraits

  /// \see QuotedStringWriter

  /// \see IdMap

  /// \see DescriptorMap

  /// \see \ref GraphReader

  /// \see \ref graph-io-page

  /// \author Balazs Dezso

  template <typename _Graph, typename _WriterTraits = DefaultWriterTraits> 

  class GraphWriter {

  public:

    typedef _Graph Graph;

    typedef typename Graph::Node Node;

    typedef typename Graph::Edge Edge;

    typedef _WriterTraits WriterTraits;

    /// \brief Construct a new GraphWriter.

    ///

    /// This function constructs a new GraphWriter to write the given graph

    /// to the given stream.

    GraphWriter(std::ostream& _os, const Graph& _graph) 

      : writer(new LemonWriter(_os)), own_writer(true), 

	nodeset_writer(*writer, _graph, std::string()),

	edgeset_writer(*writer, _graph, nodeset_writer, std::string()),

	node_writer(*writer, nodeset_writer, std::string()),

	edge_writer(*writer, edgeset_writer, std::string()),

	attribute_writer(*writer, std::string()) {}

    /// \brief Construct a new GraphWriter.

    ///

    /// This function constructs a new GraphWriter to write the given graph

    /// to the given file.

    GraphWriter(const std::string& _filename, const Graph& _graph) 

      : writer(new LemonWriter(_filename)), own_writer(true), 

	nodeset_writer(*writer, _graph, std::string()),

	edgeset_writer(*writer, _graph, nodeset_writer, std::string()),

	node_writer(*writer, nodeset_writer, std::string()),

	edge_writer(*writer, edgeset_writer, std::string()),

	attribute_writer(*writer, std::string()) {}

    /// \brief Construct a new GraphWriter.

    ///

    /// This function constructs a new GraphWriter to write the given graph

    /// to the given LemonReader.

    GraphWriter(LemonWriter& _writer, const Graph& _graph)

      : writer(_writer), own_writer(false), 

	nodeset_writer(*writer, _graph, std::string()),

	edgeset_writer(*writer, _graph, nodeset_writer, std::string()),

	node_writer(*writer, nodeset_writer, std::string()),

	edge_writer(*writer, edgeset_writer, std::string()),

	attribute_writer(*writer, std::string()) {}

    /// \brief Destruct the graph writer.

    ///

    /// This function destructs the graph writer.

    ~GraphWriter() {

      if (own_writer) 

	delete writer;

    }

    /// \brief Issue a new node map writing command for the writer.

    ///

   /// This function issues a new <i> node map writing command</i> to the writer.

    template <typename Map>

    GraphWriter& writeNodeMap(std::string name, const Map& map) {

      nodeset_writer.writeNodeMap(name, map);

      return *this;

    }

    /// \brief Issue a new node map writing command for the writer.

    ///

   /// This function issues a new <i> node map writing command</i> to the writer.

    template <typename Writer, typename Map>

    GraphWriter& writeNodeMap(std::string name, const Map& map, 

			      const Writer& writer = Writer()) {

      nodeset_writer.writeNodeMap(name, map, writer);

      return *this;

    }

    /// \brief Issue a new edge map writing command for the writer.

    ///

   /// This function issues a new <i> edge map writing command</i> to the writer.

    template <typename Map>

    GraphWriter& writeEdgeMap(std::string name, const Map& map) { 

      edgeset_writer.writeEdgeMap(name, map);

      return *this;

    }

    /// \brief Issue a new edge map writing command for the writer.

    ///

   /// This function issues a new <i> edge map writing command</i> to the writer.

    template <typename Writer, typename Map>

    GraphWriter& writeEdgeMap(std::string name, const Map& map,

			      const Writer& writer = Writer()) {

      edgeset_writer.writeEdgeMap(name, map, writer);

      return *this;

    }

    /// \brief Issue a new labeled node writing command to the writer.

    ///

    /// This function issues a new <i> labeled node writing command</i> 

    /// to the writer.

    GraphWriter& writeNode(std::string name, const Node& node) {

      node_writer.writeNode(name, node);

      return *this;

    }

    /// \brief Issue a new labeled edge writing command to the writer.

    ///

    /// This function issues a new <i> labeled edge writing command</i> 

    /// to the writer.

    GraphWriter& writeEdge(std::string name, const Edge& edge) {

      edge_writer.writeEdge(name, edge);

    }

    /// \brief Issue a new attribute writing command.

    ///

    /// This function issues a new <i> attribute writing command</i> 

    /// to the writer.

    template <typename Value>

    GraphWriter& writeAttribute(std::string name, const Value& value) {

      attribute_writer.writeAttribute(name, value);

      return *this;

    }

    /// \brief Issue a new attribute writing command.

    ///

    /// This function issues a new <i> attribute writing command</i> 

    /// to the writer.

    template <typename Writer, typename Value>

    GraphWriter& writeAttribute(std::string name, const Value& value, 

			       const Writer& writer) {

      attribute_writer.writeAttribute<Writer>(name, value, writer);

      return *this;

    }

    /// \brief Conversion operator to LemonWriter.

    ///

    /// Conversion operator to LemonWriter. It makes possible

    /// to access the encapsulated \e LemonWriter, this way

    /// you can attach to this writer new instances of 

    /// \e LemonWriter::SectionWriter.

    operator LemonWriter&() {

      return *writer;

    }

    /// \brief Executes the writing commands.

    ///

    /// Executes the writing commands.

    void run() {

      writer->run();

    }

    /// \brief Write the id of the given node.

    ///

    /// It writes the id of the given node. If there was written an "id"

    /// named node map then it will write the map value belonging to the node.

    void writeId(std::ostream& os, const Node& item) const {

      nodeset_writer.writeId(os, item);

    } 

    /// \brief Write the id of the given edge.

    ///

    /// It writes the id of the given edge. If there was written an "id"

    /// named edge map then it will write the map value belonging to the edge.

    void writeId(std::ostream& os, const Edge& item) const {

      edgeset_writer.writeId(os, item);

    } 

  private:

    LemonWriter* writer;

    bool own_writer;

    NodeSetWriter<Graph, WriterTraits> nodeset_writer;

    EdgeSetWriter<Graph, WriterTraits> edgeset_writer;

    NodeWriter<Graph> node_writer;

    EdgeWriter<Graph> edge_writer;

    AttributeWriter<WriterTraits> attribute_writer;

  };

  ///\anchor writeGraph()

  ///

  /// \brief Write a graph to the output.

  ///

  /// Write a graph to the output.

  /// \param os The output stream.

  /// \param g The graph.

  template<typename Graph>

  void writeGraph(std::ostream& os, const Graph &g) {

    GraphWriter<Graph> writer(os, g);

    IdMap<Graph, typename Graph::Node> nodeIdMap(g);

    writer.writeNodeMap("id", nodeIdMap);

    IdMap<Graph, typename Graph::Edge> edgeIdMap(g);

    writer.writeEdgeMap("id", edgeIdMap);

    writer.run();

  }

  /// \brief Write a capacitated graph instance to the output.

  /// 

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

  /// edges) to the output.

  /// \param os The output stream.

  /// \param g The graph.

  /// \param capacity The capacity map.

  template<typename Graph, typename CapacityMap>

  void writeGraph(std::ostream& os, const Graph &g, 

		  const CapacityMap& capacity) {

    GraphWriter<Graph> writer(os, g);

    IdMap<Graph, typename Graph::Node> nodeIdMap(g);

    writer.writeNodeMap("id", nodeIdMap);

    IdMap<Graph, typename Graph::Edge> edgeIdMap(g);

    writer.writeEdgeMap("id", edgeIdMap);

    writer.writeEdgeMap("capacity", capacity);

    writer.run();

  }

  /// \brief Write a shortest path instance to the output.

  /// 

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

  /// edges+designated source) to the output.

  /// \param os The output stream.

  /// \param g The graph.

  /// \param capacity The capacity map.

  /// \param s The source node.

  template<typename Graph, typename CapacityMap>

  void writeGraph(std::ostream& os, const Graph &g, 

		  const CapacityMap& capacity, const typename Graph::Node &s) {

    GraphWriter<Graph> writer(os, g);

    IdMap<Graph, typename Graph::Node> nodeIdMap(g);

    writer.writeNodeMap("id", nodeIdMap);

    IdMap<Graph, typename Graph::Edge> edgeIdMap(g);

    writer.writeEdgeMap("id", edgeIdMap);

    writer.writeEdgeMap("capacity", capacity);

    writer.writeNode("source", s);

    writer.run();

  }

  /// \brief Write a max flow instance to the output.

  ///

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

  /// edges+designated source and target) to the output.

  ///

  /// \param os The output 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 writeGraph(std::ostream& os, const Graph &g, 

		  const CapacityMap& capacity, const typename Graph::Node &s,

		  const typename Graph::Node &t) {

    GraphWriter<Graph> writer(os, g);

    IdMap<Graph, typename Graph::Node> nodeIdMap(g);

    writer.writeNodeMap("id", nodeIdMap);

    IdMap<Graph, typename Graph::Edge> edgeIdMap(g);

    writer.writeEdgeMap("id", edgeIdMap);

    writer.writeEdgeMap("capacity", capacity);

    writer.writeNode("source", s);

    writer.writeNode("target", t);

    writer.run();

  }

  /// \brief Write a min cost flow instance to the output.

  ///

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

  /// function on the edges+designated source and target) to the output.

  ///

  /// \param os The output 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 writeGraph(std::ostream& os, const Graph &g, 

		  const CapacityMap& capacity, const typename Graph::Node &s,

		  const typename Graph::Node &t, const CostMap& cost) {

    GraphWriter<Graph> writer(os, g);

    IdMap<Graph, typename Graph::Node> nodeIdMap(g);

    writer.writeNodeMap("id", nodeIdMap);

    IdMap<Graph, typename Graph::Edge> edgeIdMap(g);

    writer.writeEdgeMap("id", edgeIdMap);

    writer.writeEdgeMap("capacity", capacity);

    writer.writeEdgeMap("cost", cost);

    writer.writeNode("source", s);

    writer.writeNode("target", t);

    writer.run();

  }

  /// \brief The undirected graph writer class.

  ///

  /// The \c UndirGraphWriter class provides the undir graph output. To write 

  /// a graph you should first give writing commands to the writer. You can 

  /// declare write command as \c NodeMap, \c EdgeMap or \c UndirEdgeMap 

  /// writing and labeled Node, Edge or UndirEdge writing.

  ///

  /// \code

  /// UndirGraphWriter<UndirListGraph> writer(std::cout, graph);

  /// \endcode

  ///

  /// The \c writeNodeMap() function declares a \c NodeMap writing 

  /// command in the \c UndirGraphWriter. You should give as parameter 

  /// the name of the map and the map object. The NodeMap writing 

  /// command with name "id" should write a unique map because it 

  /// is regarded as ID map.

  ///

  /// \code

  /// IdMap<UndirListGraph, Node> nodeIdMap;

  /// writer.writeNodeMap("id", nodeIdMap);

  ///

  /// writer.writeNodeMap("coords", coords);

  /// writer.writeNodeMap("color", colorMap);

  /// \endcode

  ///

  /// With the \c writeUndirEdgeMap() member function you can give an 

  /// undirected edge map writing command similar to the NodeMaps.

  ///

  /// \code

  /// DescriptorMap<ListGraph, Edge, ListGraph::EdgeMap<int> > 

  ///   edgeDescMap(graph);

  /// writer.writeUndirEdgeMap("descriptor", edgeDescMap);

  ///

  /// writer.writeUndirEdgeMap("weight", weightMap);

  /// writer.writeUndirEdgeMap("label", labelMap);

  /// \endcode

  /// 

  /// The EdgeMap handling is just a syntactical sugar. It writes

  /// two undirected edge map with '+' and '-' prefix in the name.

  ///

  /// \code

  /// writer.writeEdgeMap("capacity", capacityMap);

  /// \endcode

  ///

  ///

  /// With \c writeNode() and \c writeUndirEdge() functions you can 

  /// designate nodes and undirected edges in the graph. For example, you can 

  /// write out the source and target of the graph.

  ///

  /// \code

  /// writer.writeNode("source", sourceNode);

  /// writer.writeNode("target", targetNode);

  ///

  /// writer.writeUndirEdge("observed", undirEdge);

  /// \endcode

  ///

  /// After you give all write commands you must call the \c run() member

  /// function, which executes all the writing commands.

  ///

  /// \code

  /// writer.run();

  /// \endcode

  ///

  /// \see DefaultWriterTraits

  /// \see QuotedStringWriter

  /// \see IdMap

  /// \see DescriptorMap

  /// \see \ref GraphWriter

  /// \see \ref graph-io-page

  /// \author Balazs Dezso

  template <typename _Graph, typename _WriterTraits = DefaultWriterTraits> 

  class UndirGraphWriter {

  public:

    typedef _Graph Graph;

    typedef typename Graph::Node Node;

    typedef typename Graph::Edge Edge;

    typedef typename Graph::UndirEdge UndirEdge;

    typedef _WriterTraits WriterTraits;

    /// \brief Construct a new UndirGraphWriter.

    ///

    /// Construct a new UndirGraphWriter. It writes the given graph

    /// to the given stream.

    UndirGraphWriter(std::ostream& _os, const Graph& _graph) 

      : writer(new LemonWriter(_os)), own_writer(true), 

	nodeset_writer(*writer, _graph, std::string()),

	undir_edgeset_writer(*writer, _graph, nodeset_writer, std::string()),

	node_writer(*writer, nodeset_writer, std::string()),

	undir_edge_writer(*writer, undir_edgeset_writer, std::string()),

	attribute_writer(*writer, std::string()) {}

    /// \brief Construct a new UndirGraphWriter.

    ///

    /// Construct a new UndirGraphWriter. It writes the given graph

    /// to the given file.

    UndirGraphWriter(const std::string& _filename, const Graph& _graph) 

      : writer(new LemonWriter(_filename)), own_writer(true), 

	nodeset_writer(*writer, _graph, std::string()),

	undir_edgeset_writer(*writer, _graph, nodeset_writer, std::string()),

	node_writer(*writer, nodeset_writer, std::string()),

	undir_edge_writer(*writer, undir_edgeset_writer, std::string()),

	attribute_writer(*writer, std::string()) {}

    /// \brief Construct a new UndirGraphWriter.

    ///

    /// Construct a new UndirGraphWriter. It writes the given graph

    /// to given LemonReader.

    UndirGraphWriter(LemonWriter& _writer, const Graph& _graph)

      : writer(_writer), own_writer(false), 

	nodeset_writer(*writer, _graph, std::string()),

	undir_edgeset_writer(*writer, _graph, nodeset_writer, std::string()),

	node_writer(*writer, nodeset_writer, std::string()),

	undir_edge_writer(*writer, undir_edgeset_writer, std::string()),

	attribute_writer(*writer, std::string()) {}

    /// \brief Destruct the graph writer.

    ///

    /// Destruct the graph writer.

    ~UndirGraphWriter() {

      if (own_writer) 

	delete writer;

    }

    /// \brief Issue a new node map writing command to the writer.

    ///

   /// This function issues a new <i> node map writing command</i> to the writer.

    template <typename Map>

    UndirGraphWriter& writeNodeMap(std::string name, const Map& map) {

      nodeset_writer.writeNodeMap(name, map);

      return *this;

    }

    /// \brief Issue a new node map writing command to the writer.

    ///

   /// This function issues a new <i> node map writing command</i> to the writer.

    template <typename Writer, typename Map>

    UndirGraphWriter& writeNodeMap(std::string name, const Map& map, 

			      const Writer& writer = Writer()) {

      nodeset_writer.writeNodeMap(name, map, writer);

      return *this;

    }

    /// \brief Issue a new edge map writing command to the writer.

    ///

   /// This function issues a new <i> edge map writing command</i> to the writer.

    template <typename Map>

    UndirGraphWriter& writeEdgeMap(std::string name, const Map& map) { 

      undir_edgeset_writer.writeEdgeMap(name, map);

      return *this;

    }

    /// \brief Issue a new edge map writing command to the writer.

    ///

   /// This function issues a new <i> edge map writing command</i> to the writer.

    template <typename Writer, typename Map>

    UndirGraphWriter& writeEdgeMap(std::string name, const Map& map,

				   const Writer& writer = Writer()) {

      undir_edgeset_writer.writeEdgeMap(name, map, writer);

      return *this;

    }

    /// \brief Issue a new undirected edge map writing command to the writer.

    ///

    /// This function issues a new <i> undirected edge map writing

    /// command</i> to the writer.

    template <typename Map>

    UndirGraphWriter& writeUndirEdgeMap(std::string name, const Map& map) { 

      undir_edgeset_writer.writeUndirEdgeMap(name, map);

      return *this;

    }

    /// \brief Issue a new undirected edge map writing command to the writer.

    ///

    /// This function issues a new <i> undirected edge map writing

    /// command</i> to the writer.

    template <typename Writer, typename Map>

    UndirGraphWriter& writeUndirEdgeMap(std::string name, const Map& map,

					const Writer& writer = Writer()) {

      undir_edgeset_writer.writeUndirEdgeMap(name, map, writer);

      return *this;

    }

    /// \brief Issue a new labeled node writer to the writer.

    ///

    /// This function issues a new <i> labeled node writing

    /// command</i> to the writer.

    UndirGraphWriter& writeNode(std::string name, const Node& node) {

      node_writer.writeNode(name, node);

      return *this;

    }

    /// \brief Issue a new labeled edge writer to the writer.

    ///

    /// This function issues a new <i> labeled edge writing

    /// command</i> to the writer.

    UndirGraphWriter& writeEdge(std::string name, const Edge& edge) {

      undir_edge_writer.writeEdge(name, edge);

    }

    /// \brief Issue a new labeled undirected edge writing command to

    /// the writer.

    ///

    /// Issue a new <i>labeled undirected edge writing command</i> to

    /// the writer.

    UndirGraphWriter& writeUndirEdge(std::string name, const UndirEdge& edge) {

      undir_edge_writer.writeUndirEdge(name, edge);

    }

    /// \brief Issue a new attribute writing command.

    ///

    /// This function issues a new <i> attribute writing

    /// command</i> to the writer.

    template <typename Value>

    UndirGraphWriter& writeAttribute(std::string name, const Value& value) {

      attribute_writer.writeAttribute(name, value);

      return *this;

    }

    /// \brief Issue a new attribute writing command.

    ///

    /// This function issues a new <i> attribute writing

    /// command</i> to the writer.

    template <typename Writer, typename Value>

    UndirGraphWriter& writeAttribute(std::string name, const Value& value, 

			       const Writer& writer) {

      attribute_writer.writeAttribute<Writer>(name, value, writer);

      return *this;

    }

    /// \brief Conversion operator to LemonWriter.

    ///

    /// Conversion operator to LemonWriter. It makes possible

    /// to access the encapsulated \e LemonWriter, this way

    /// you can attach to this writer new instances of 

    /// \e LemonWriter::SectionWriter.

    operator LemonWriter&() {

      return *writer;

    }

    /// \brief Executes the writing commands.

    ///

    /// Executes the writing commands.

    void run() {

      writer->run();

    }

    /// \brief Write the id of the given node.

    ///

    /// It writes the id of the given node. If there was written an "id"

    /// named node map then it will write the map value belonging to the node.

    void writeId(std::ostream& os, const Node& item) const {

      nodeset_writer.writeId(os, item);

    } 

    /// \brief Write the id of the given edge.

    ///

    /// It writes the id of the given edge. If there was written an "id"

    /// named edge map then it will write the map value belonging to the edge.

    void writeId(std::ostream& os, const Edge& item) const {

      undir_edgeset_writer.writeId(os, item);

    } 

    /// \brief Write the id of the given undirected edge.

    ///

    /// It writes the id of the given undirected edge. If there was written 

    /// an "id" named edge map then it will write the map value belonging to 

    /// the edge.

    void writeId(std::ostream& os, const UndirEdge& item) const {

      undir_edgeset_writer.writeId(os, item);

    } 

  private:

    LemonWriter* writer;

    bool own_writer;

    NodeSetWriter<Graph, WriterTraits> nodeset_writer;

    UndirEdgeSetWriter<Graph, WriterTraits> undir_edgeset_writer;

    NodeWriter<Graph> node_writer;

    UndirEdgeWriter<Graph> undir_edge_writer;

    AttributeWriter<WriterTraits> attribute_writer;

  };

  /// \brief Write an undirected graph to the output.

  ///

  /// Write an undirected graph to the output.

  /// \param os The output stream.

  /// \param g The graph.

  template<typename Graph>

  void writeUndirGraph(std::ostream& os, const Graph &g) {

    UndirGraphWriter<Graph> writer(os, g);

    writer.run();

  }

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

  /// map on the edges) to the output.

  ///

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

  /// map on the edges) to the output.

  /// \param os The output stream.

  /// \param g The graph.

  /// \param capacity The capacity undirected map.

  template<typename Graph, typename CapacityMap>

  void writeUndirGraph(std::ostream& os, const Graph &g, 

		       const CapacityMap& capacity) {

    UndirGraphWriter<Graph> writer(os, g);

    writer.writeUndirEdgeMap("capacity", capacity);

    writer.run();

  }

  /// @}

}

#endif