///

   ///

   ///\param Graph The directed graph type the algorithm runs on.

   ///\param Graph The directed graph type the algorithm runs on.

   ///\param Num The number type of the capacities and the flow values.

   ///\param Num The number type of the capacities and the flow values.

   ///\param CapacityMap The capacity map type.

   ///\param CapacityMap The capacity map type.

   ///\param FlowMap The flow map type.

   ///\param FlowMap The flow map type.

   ///

   ///

   ///\author Jacint Szabo 

   ///\author Jacint Szabo 

   ///\todo Second template parameter is superfluous

   ///\todo Second template parameter is superfluous

   template <typename Graph, typename Num,

   template <typename Graph, typename Num,

 	    typename CapacityMap=typename Graph::template EdgeMap<Num>,

 	    typename CapacityMap=typename Graph::template EdgeMap<Num>,

             typename FlowMap=typename Graph::template EdgeMap<Num>,

             typename FlowMap=typename Graph::template EdgeMap<Num>,

   class Preflow {

   class Preflow {

   protected:

   protected:

     typedef typename Graph::Node Node;

     typedef typename Graph::Node Node;

     typedef typename Graph::NodeIt NodeIt;

     typedef typename Graph::NodeIt NodeIt;

     typedef typename Graph::EdgeIt EdgeIt;

     typedef typename Graph::EdgeIt EdgeIt;

     Node _source;

     Node _source;

     Node _target;

     Node _target;

     const CapacityMap* _capacity;

     const CapacityMap* _capacity;

     FlowMap* _flow;

     FlowMap* _flow;

     int _node_num;      //the number of nodes of G

     int _node_num;      //the number of nodes of G

     typename Graph::template NodeMap<int> level;  

     typename Graph::template NodeMap<int> level;  

     typename Graph::template NodeMap<Num> excess;

     typename Graph::template NodeMap<Num> excess;

     ///\param _gr The directed graph the algorithm runs on. 

     ///\param _gr The directed graph the algorithm runs on. 

     ///\param _s The source node.

     ///\param _s The source node.

     ///\param _t The target node.

     ///\param _t The target node.

     ///\param _cap The capacity of the edges. 

     ///\param _cap The capacity of the edges. 

     ///\param _f The flow of the edges. 

     ///\param _f The flow of the edges. 

     ///Except the graph, all of these parameters can be reset by

     ///Except the graph, all of these parameters can be reset by

     ///calling \ref source, \ref target, \ref capacityMap and \ref

     ///calling \ref source, \ref target, \ref capacityMap and \ref

     ///flowMap, resp.

     ///flowMap, resp.

     Preflow(const Graph& _gr, Node _s, Node _t, 

     Preflow(const Graph& _gr, Node _s, Node _t, 

             const CapacityMap& _cap, FlowMap& _f,

             const CapacityMap& _cap, FlowMap& _f,

 	_g(&_gr), _source(_s), _target(_t), _capacity(&_cap),

 	_g(&_gr), _source(_s), _target(_t), _capacity(&_cap),

 	_flow(&_f), _surely(_sr),

 	_flow(&_f), _surely(_sr),

 	_node_num(countNodes(_gr)), level(_gr), excess(_gr,0), 

 	_node_num(countNodes(_gr)), level(_gr), excess(_gr,0), 

 	flow_prop(NO_FLOW), status(AFTER_NOTHING) { 

 	flow_prop(NO_FLOW), status(AFTER_NOTHING) { 

 	if ( _source==_target )

 	if ( _source==_target )

     ///Give a reference to the tolerance handler class

     ///Give a reference to the tolerance handler class

     ///Give a reference to the tolerance handler class

     ///Give a reference to the tolerance handler class

     ///\sa Tolerance

     ///\sa Tolerance

     ///Runs the preflow algorithm.  

     ///Runs the preflow algorithm.  

     ///Runs the preflow algorithm.

     ///Runs the preflow algorithm.

     ///

     ///