/// \brief Returns a residual capacity map

     ///

     /// This function just returns a residual capacity map.

     ResidualCapacity residualCapacity() const {

       return ResidualCapacity(*this);

     }

   /// \brief Returns a (read-only) Residual adaptor

   ///

   /// This function just returns a (read-only) \ref Residual adaptor.

   /// \ingroup graph_adaptors

   /// \relates Residual

   template<typename Digraph, typename CapacityMap, typename FlowMap>

   Residual<Digraph, CapacityMap, FlowMap>

   residual(const Digraph& digraph,

            const CapacityMap& capacity,

            FlowMap& flow)

   {

     return Residual<Digraph, CapacityMap, FlowMap> (digraph, capacity, flow);

   }