RhodeCode

        LEMON_ASSERT(false, "Elevator is not initialized");

        return 0; // ignore warnings

      }

    };

    /// \brief \ref named-templ-param "Named parameter" for setting

    /// Elevator type

    ///

    /// \ref named-templ-param "Named parameter" for setting Elevator

    /// type. If this named parameter is used, then an external

    /// elevator object must be passed to the algorithm using the

    /// \ref elevator(Elevator&) "elevator()" function before calling

    /// \ref run() or \ref init().

    /// \sa SetStandardElevator

    template <typename T>

    struct SetElevator

      : public Circulation<Digraph, LowerMap, UpperMap, SupplyMap,

                           SetElevatorTraits<T> > {

      typedef Circulation<Digraph, LowerMap, UpperMap, SupplyMap,

                          SetElevatorTraits<T> > Create;

    };

    template <typename T>

    struct SetStandardElevatorTraits : public Traits {

      typedef T Elevator;

      static Elevator *createElevator(const Digraph& digraph, int max_level) {

        return new Elevator(digraph, max_level);

      }

    };

    /// \brief \ref named-templ-param "Named parameter" for setting

    /// Elevator type with automatic allocation

    ///

    /// \ref named-templ-param "Named parameter" for setting Elevator

    /// type with automatic allocation.

    /// The Elevator should have standard constructor interface to be

    /// able to automatically created by the algorithm (i.e. the

    /// digraph and the maximum level should be passed to it).

    /// However an external elevator object could also be passed to the

    /// algorithm with the \ref elevator(Elevator&) "elevator()" function

    /// before calling \ref run() or \ref init().

    /// \sa SetElevator

    template <typename T>

    struct SetStandardElevator

      : public Circulation<Digraph, LowerMap, UpperMap, SupplyMap,

                       SetStandardElevatorTraits<T> > {

      typedef Circulation<Digraph, LowerMap, UpperMap, SupplyMap,

                      SetStandardElevatorTraits<T> > Create;

    };

    /// @}

  protected:

    Circulation() {}

  public:

    /// Constructor.

    /// The constructor of the class.

    ///

    /// \param graph The digraph the algorithm runs on.

    /// \param lower The lower bounds for the flow values on the arcs.

    /// \param upper The upper bounds (capacities) for the flow values 

    /// on the arcs.

    /// \param supply The signed supply values of the nodes.

    Circulation(const Digraph &graph, const LowerMap &lower,

                const UpperMap &upper, const SupplyMap &supply)

      : _g(graph), _lo(&lower), _up(&upper), _supply(&supply),

        _flow(NULL), _local_flow(false), _level(NULL), _local_level(false),

        _excess(NULL) {}

    /// Destructor.

    ~Circulation() {

      destroyStructures();

    }

  private:

    bool checkBoundMaps() {

      for (ArcIt e(_g);e!=INVALID;++e) {

        if (_tol.less((*_up)[e], (*_lo)[e])) return false;

      }

      return true;

    }

    void createStructures() {

      _node_num = _el = countNodes(_g);

      if (!_flow) {

        _flow = Traits::createFlowMap(_g);

        _local_flow = true;

      }

      if (!_level) {

        _level = Traits::createElevator(_g, _node_num);

        _local_level = true;

      }

      if (!_excess) {

        _excess = new ExcessMap(_g);

      }

    }

    void destroyStructures() {

      if (_local_flow) {

        delete _flow;

      }

      if (_local_level) {

        delete _level;

      }

      if (_excess) {

        delete _excess;

      }

    }

  public:

    /// Sets the lower bound map.

    /// Sets the lower bound map.

    /// \return <tt>(*this)</tt>

    Circulation& lowerMap(const LowerMap& map) {

      _lo = ↦

      return *this;

    }

    /// Sets the upper bound (capacity) map.

    /// Sets the upper bound (capacity) map.

    /// \return <tt>(*this)</tt>

    Circulation& upperMap(const UpperMap& map) {

      _up = ↦

      return *this;

    }

    /// Sets the supply map.

    /// Sets the supply map.

    /// \return <tt>(*this)</tt>

    Circulation& supplyMap(const SupplyMap& map) {

      _supply = ↦

      return *this;

    }

    /// \brief Sets the flow map.

    ///

    /// Sets the flow map.

    /// If you don't use this function before calling \ref run() or

    /// \ref init(), an instance will be allocated automatically.

    /// The destructor deallocates this automatically allocated map,

    /// of course.

    /// \return <tt>(*this)</tt>

    Circulation& flowMap(FlowMap& map) {

      if (_local_flow) {

        delete _flow;

        _local_flow = false;

      }

      _flow = ↦

      return *this;

    }

    /// \brief Sets the elevator used by algorithm.

    ///

    /// Sets the elevator used by algorithm.

    /// If you don't use this function before calling \ref run() or

    /// \ref init(), an instance will be allocated automatically.

    /// The destructor deallocates this automatically allocated elevator,

    /// of course.

    /// \return <tt>(*this)</tt>

    Circulation& elevator(Elevator& elevator) {

      if (_local_level) {

        delete _level;

        _local_level = false;

      }

      _level = &elevator;

      return *this;

    }

    /// \brief Returns a const reference to the elevator.

    ///

    /// Returns a const reference to the elevator.

    ///

    /// \pre Either \ref run() or \ref init() must be called before

    /// using this function.

    const Elevator& elevator() const {

      return *_level;

    }

    /// \brief Sets the tolerance used by algorithm.

    ///

    /// Sets the tolerance used by algorithm.

      _tol = tolerance;

      return *this;

    }

    /// \brief Returns a const reference to the tolerance.

    ///

    /// Returns a const reference to the tolerance.

    const Tolerance& tolerance() const {

    }

    /// \name Execution Control

    /// The simplest way to execute the algorithm is to call \ref run().\n

    /// If you need more control on the initial solution or the execution,

    /// first you have to call one of the \ref init() functions, then

    /// the \ref start() function.

    ///@{

    /// Initializes the internal data structures.

    /// Initializes the internal data structures and sets all flow values

    /// to the lower bound.

    void init()

    {

      LEMON_DEBUG(checkBoundMaps(),

        "Upper bounds must be greater or equal to the lower bounds");

      createStructures();

      for(NodeIt n(_g);n!=INVALID;++n) {

        (*_excess)[n] = (*_supply)[n];

      }

      for (ArcIt e(_g);e!=INVALID;++e) {

        _flow->set(e, (*_lo)[e]);

        (*_excess)[_g.target(e)] += (*_flow)[e];

        (*_excess)[_g.source(e)] -= (*_flow)[e];

      }

      // global relabeling tested, but in general case it provides

      // worse performance for random digraphs

      _level->initStart();

      for(NodeIt n(_g);n!=INVALID;++n)

        _level->initAddItem(n);

      _level->initFinish();

      for(NodeIt n(_g);n!=INVALID;++n)

        if(_tol.positive((*_excess)[n]))

          _level->activate(n);

    }

    /// Initializes the internal data structures using a greedy approach.

    /// Initializes the internal data structures using a greedy approach

    /// to construct the initial solution.

    void greedyInit()

    {

      LEMON_DEBUG(checkBoundMaps(),

        "Upper bounds must be greater or equal to the lower bounds");

      createStructures();

      for(NodeIt n(_g);n!=INVALID;++n) {

        (*_excess)[n] = (*_supply)[n];

      }

      for (ArcIt e(_g);e!=INVALID;++e) {

        if (!_tol.less(-(*_excess)[_g.target(e)], (*_up)[e])) {

          _flow->set(e, (*_up)[e]);

          (*_excess)[_g.target(e)] += (*_up)[e];

          (*_excess)[_g.source(e)] -= (*_up)[e];

        } else if (_tol.less(-(*_excess)[_g.target(e)], (*_lo)[e])) {

          _flow->set(e, (*_lo)[e]);

          (*_excess)[_g.target(e)] += (*_lo)[e];

          (*_excess)[_g.source(e)] -= (*_lo)[e];

        } else {

          Value fc = -(*_excess)[_g.target(e)];

          _flow->set(e, fc);

          (*_excess)[_g.target(e)] = 0;

          (*_excess)[_g.source(e)] -= fc;

        }

      }

      _level->initStart();

      for(NodeIt n(_g);n!=INVALID;++n)

        _level->initAddItem(n);

      _level->initFinish();

      for(NodeIt n(_g);n!=INVALID;++n)

        if(_tol.positive((*_excess)[n]))

          _level->activate(n);

    }

    ///Executes the algorithm

    ///This function executes the algorithm.

    ///

    ///\return \c true if a feasible circulation is found.

    ///

    ///\sa barrier()

    ///\sa barrierMap()

    bool start()

    {

      Node act;

      Node bact=INVALID;

      Node last_activated=INVALID;

      while((act=_level->highestActive())!=INVALID) {

        int actlevel=(*_level)[act];

        int mlevel=_node_num;

        Value exc=(*_excess)[act];

        for(OutArcIt e(_g,act);e!=INVALID; ++e) {

          Node v = _g.target(e);

          Value fc=(*_up)[e]-(*_flow)[e];

          if(!_tol.positive(fc)) continue;

          if((*_level)[v]<actlevel) {

            if(!_tol.less(fc, exc)) {

              _flow->set(e, (*_flow)[e] + exc);

              (*_excess)[v] += exc;

              if(!_level->active(v) && _tol.positive((*_excess)[v]))

                _level->activate(v);

              (*_excess)[act] = 0;

              _level->deactivate(act);

              goto next_l;

            }

            else {

              _flow->set(e, (*_up)[e]);

              (*_excess)[v] += fc;

              if(!_level->active(v) && _tol.positive((*_excess)[v]))

                _level->activate(v);

              exc-=fc;

            }

          }

          else if((*_level)[v]<mlevel) mlevel=(*_level)[v];

        }

        for(InArcIt e(_g,act);e!=INVALID; ++e) {

          Node v = _g.source(e);

          Value fc=(*_flow)[e]-(*_lo)[e];

          if(!_tol.positive(fc)) continue;

          if((*_level)[v]<actlevel) {

            if(!_tol.less(fc, exc)) {

              _flow->set(e, (*_flow)[e] - exc);

              (*_excess)[v] += exc;

              if(!_level->active(v) && _tol.positive((*_excess)[v]))

                _level->activate(v);

              (*_excess)[act] = 0;

              _level->deactivate(act);

              goto next_l;

            }

            else {

              _flow->set(e, (*_lo)[e]);

              (*_excess)[v] += fc;

              if(!_level->active(v) && _tol.positive((*_excess)[v]))

                _level->activate(v);

              exc-=fc;

            }

          }

          else if((*_level)[v]<mlevel) mlevel=(*_level)[v];

        }

        (*_excess)[act] = exc;

        if(!_tol.positive(exc)) _level->deactivate(act);

        else if(mlevel==_node_num) {

          _level->liftHighestActiveToTop();

          _el = _node_num;

          return false;

        }

        else {

          _level->liftHighestActive(mlevel+1);

          if(_level->onLevel(actlevel)==0) {

            _el = actlevel;

            return false;

          }

        }

      next_l:

        ;

      }

      return true;

    }

    /// Runs the algorithm.

    /// This function runs the algorithm.

    ///

    /// \return \c true if a feasible circulation is found.

    ///

    /// \note Apart from the return value, c.run() is just a shortcut of

    /// the following code.

    /// \code

    ///   c.greedyInit();

    ///   c.start();

    /// \endcode

    bool run() {

      greedyInit();

      return start();

    }

    /// @}

    /// \name Query Functions

    /// The results of the circulation algorithm can be obtained using

      if (_excess) {

        delete _excess;

      }

    }

  public:

    typedef Preflow Create;

    ///\name Named Template Parameters

    ///@{

    template <typename T>

    struct SetFlowMapTraits : public Traits {

      typedef T FlowMap;

      static FlowMap *createFlowMap(const Digraph&) {

        LEMON_ASSERT(false, "FlowMap is not initialized");

        return 0; // ignore warnings

      }

    };

    /// \brief \ref named-templ-param "Named parameter" for setting

    /// FlowMap type

    ///

    /// \ref named-templ-param "Named parameter" for setting FlowMap

    /// type.

    template <typename T>

    struct SetFlowMap

      : public Preflow<Digraph, CapacityMap, SetFlowMapTraits<T> > {

      typedef Preflow<Digraph, CapacityMap,

                      SetFlowMapTraits<T> > Create;

    };

    template <typename T>

    struct SetElevatorTraits : public Traits {

      typedef T Elevator;

      static Elevator *createElevator(const Digraph&, int) {

        LEMON_ASSERT(false, "Elevator is not initialized");

        return 0; // ignore warnings

      }

    };

    /// \brief \ref named-templ-param "Named parameter" for setting

    /// Elevator type

    ///

    /// \ref named-templ-param "Named parameter" for setting Elevator

    /// type. If this named parameter is used, then an external

    /// elevator object must be passed to the algorithm using the

    /// \ref elevator(Elevator&) "elevator()" function before calling

    /// \ref run() or \ref init().

    /// \sa SetStandardElevator

    template <typename T>

    struct SetElevator

      : public Preflow<Digraph, CapacityMap, SetElevatorTraits<T> > {

      typedef Preflow<Digraph, CapacityMap,

                      SetElevatorTraits<T> > Create;

    };

    template <typename T>

    struct SetStandardElevatorTraits : public Traits {

      typedef T Elevator;

      static Elevator *createElevator(const Digraph& digraph, int max_level) {

        return new Elevator(digraph, max_level);

      }

    };

    /// \brief \ref named-templ-param "Named parameter" for setting

    /// Elevator type with automatic allocation

    ///

    /// \ref named-templ-param "Named parameter" for setting Elevator

    /// type with automatic allocation.

    /// The Elevator should have standard constructor interface to be

    /// able to automatically created by the algorithm (i.e. the

    /// digraph and the maximum level should be passed to it).

    /// However an external elevator object could also be passed to the

    /// algorithm with the \ref elevator(Elevator&) "elevator()" function

    /// before calling \ref run() or \ref init().

    /// \sa SetElevator

    template <typename T>

    struct SetStandardElevator

      : public Preflow<Digraph, CapacityMap,

                       SetStandardElevatorTraits<T> > {

      typedef Preflow<Digraph, CapacityMap,

                      SetStandardElevatorTraits<T> > Create;

    };

    /// @}

  protected:

    Preflow() {}

  public:

    /// \brief The constructor of the class.

    ///

    /// The constructor of the class.

    /// \param digraph The digraph the algorithm runs on.

    /// \param capacity The capacity of the arcs.

    /// \param source The source node.

    /// \param target The target node.

    Preflow(const Digraph& digraph, const CapacityMap& capacity,

            Node source, Node target)

      : _graph(digraph), _capacity(&capacity),

        _node_num(0), _source(source), _target(target),

        _flow(0), _local_flow(false),

        _level(0), _local_level(false),

        _excess(0), _tolerance(), _phase() {}

    /// \brief Destructor.

    ///

    /// Destructor.

    ~Preflow() {

      destroyStructures();

    }

    /// \brief Sets the capacity map.

    ///

    /// Sets the capacity map.

    /// \return <tt>(*this)</tt>

    Preflow& capacityMap(const CapacityMap& map) {

      _capacity = ↦

      return *this;

    }

    /// \brief Sets the flow map.

    ///

    /// Sets the flow map.

    /// If you don't use this function before calling \ref run() or

    /// \ref init(), an instance will be allocated automatically.

    /// The destructor deallocates this automatically allocated map,

    /// of course.

    /// \return <tt>(*this)</tt>

    Preflow& flowMap(FlowMap& map) {

      if (_local_flow) {

        delete _flow;

        _local_flow = false;

      }

      _flow = ↦

      return *this;

    }

    /// \brief Sets the source node.

    ///

    /// Sets the source node.

    /// \return <tt>(*this)</tt>

    Preflow& source(const Node& node) {

      _source = node;

      return *this;

    }

    /// \brief Sets the target node.

    ///

    /// Sets the target node.

    /// \return <tt>(*this)</tt>

    Preflow& target(const Node& node) {

      _target = node;

      return *this;

    }

    /// \brief Sets the elevator used by algorithm.

    ///

    /// Sets the elevator used by algorithm.

    /// If you don't use this function before calling \ref run() or

    /// \ref init(), an instance will be allocated automatically.

    /// The destructor deallocates this automatically allocated elevator,

    /// of course.

    /// \return <tt>(*this)</tt>

    Preflow& elevator(Elevator& elevator) {

      if (_local_level) {

        delete _level;

        _local_level = false;

      }

      _level = &elevator;

      return *this;

    }

    /// \brief Returns a const reference to the elevator.

    ///

    /// Returns a const reference to the elevator.

    ///

    /// \pre Either \ref run() or \ref init() must be called before

    /// using this function.

    const Elevator& elevator() const {

      return *_level;

    }

    /// \brief Sets the tolerance used by algorithm.

    ///

    /// Sets the tolerance used by algorithm.

      _tolerance = tolerance;

      return *this;

    }

    /// \brief Returns a const reference to the tolerance.

    ///

    /// Returns a const reference to the tolerance.

    const Tolerance& tolerance() const {

    }

    /// \name Execution Control

    /// The simplest way to execute the preflow algorithm is to use

    /// \ref run() or \ref runMinCut().\n

    /// If you need more control on the initial solution or the execution,

    /// first you have to call one of the \ref init() functions, then

    /// \ref startFirstPhase() and if you need it \ref startSecondPhase().

    ///@{

    /// \brief Initializes the internal data structures.

    ///

    /// Initializes the internal data structures and sets the initial

    /// flow to zero on each arc.

    void init() {

      createStructures();

      _phase = true;

      for (NodeIt n(_graph); n != INVALID; ++n) {

        (*_excess)[n] = 0;

      }

      for (ArcIt e(_graph); e != INVALID; ++e) {

        _flow->set(e, 0);

      }

      typename Digraph::template NodeMap<bool> reached(_graph, false);

      _level->initStart();

      _level->initAddItem(_target);

      std::vector<Node> queue;

      reached[_source] = true;

      queue.push_back(_target);

      reached[_target] = true;

      while (!queue.empty()) {

        _level->initNewLevel();

        std::vector<Node> nqueue;

        for (int i = 0; i < int(queue.size()); ++i) {

          Node n = queue[i];

          for (InArcIt e(_graph, n); e != INVALID; ++e) {

            Node u = _graph.source(e);

            if (!reached[u] && _tolerance.positive((*_capacity)[e])) {

              reached[u] = true;

              _level->initAddItem(u);

              nqueue.push_back(u);

            }

          }

        }

        queue.swap(nqueue);

      }

      _level->initFinish();

      for (OutArcIt e(_graph, _source); e != INVALID; ++e) {

        if (_tolerance.positive((*_capacity)[e])) {

          Node u = _graph.target(e);

          if ((*_level)[u] == _level->maxLevel()) continue;

          _flow->set(e, (*_capacity)[e]);

          (*_excess)[u] += (*_capacity)[e];

          if (u != _target && !_level->active(u)) {

            _level->activate(u);

          }

        }

      }

    }

    /// \brief Initializes the internal data structures using the

    /// given flow map.

    ///

    /// Initializes the internal data structures and sets the initial

    /// flow to the given \c flowMap. The \c flowMap should contain a

    /// flow or at least a preflow, i.e. at each node excluding the

    /// source node the incoming flow should greater or equal to the

    /// outgoing flow.

    /// \return \c false if the given \c flowMap is not a preflow.

    template <typename FlowMap>

    bool init(const FlowMap& flowMap) {

      createStructures();

      for (ArcIt e(_graph); e != INVALID; ++e) {

        _flow->set(e, flowMap[e]);

      }

      for (NodeIt n(_graph); n != INVALID; ++n) {

        Value excess = 0;

        for (InArcIt e(_graph, n); e != INVALID; ++e) {

          excess += (*_flow)[e];

        }

        for (OutArcIt e(_graph, n); e != INVALID; ++e) {

          excess -= (*_flow)[e];

        }

        if (excess < 0 && n != _source) return false;

        (*_excess)[n] = excess;

      }

      typename Digraph::template NodeMap<bool> reached(_graph, false);

      _level->initStart();

      _level->initAddItem(_target);

      std::vector<Node> queue;

      reached[_source] = true;

      queue.push_back(_target);

      reached[_target] = true;

      while (!queue.empty()) {

        _level->initNewLevel();

        std::vector<Node> nqueue;

        for (int i = 0; i < int(queue.size()); ++i) {

          Node n = queue[i];

          for (InArcIt e(_graph, n); e != INVALID; ++e) {

            Node u = _graph.source(e);

            if (!reached[u] &&

                _tolerance.positive((*_capacity)[e] - (*_flow)[e])) {

              reached[u] = true;

              _level->initAddItem(u);

              nqueue.push_back(u);

            }

          }

          for (OutArcIt e(_graph, n); e != INVALID; ++e) {

            Node v = _graph.target(e);

            if (!reached[v] && _tolerance.positive((*_flow)[e])) {

              reached[v] = true;

              _level->initAddItem(v);

              nqueue.push_back(v);

            }

          }

        }

        queue.swap(nqueue);

      }

      _level->initFinish();

      for (OutArcIt e(_graph, _source); e != INVALID; ++e) {

        Value rem = (*_capacity)[e] - (*_flow)[e];

        if (_tolerance.positive(rem)) {

          Node u = _graph.target(e);

          if ((*_level)[u] == _level->maxLevel()) continue;

          _flow->set(e, (*_capacity)[e]);

          (*_excess)[u] += rem;

          if (u != _target && !_level->active(u)) {

            _level->activate(u);

          }

        }

      }

      for (InArcIt e(_graph, _source); e != INVALID; ++e) {

        Value rem = (*_flow)[e];

        if (_tolerance.positive(rem)) {

          Node v = _graph.source(e);

          if ((*_level)[v] == _level->maxLevel()) continue;

          _flow->set(e, 0);

          (*_excess)[v] += rem;

          if (v != _target && !_level->active(v)) {

            _level->activate(v);

          }

        }

      }

      return true;

    }

    /// \brief Starts the first phase of the preflow algorithm.

    ///

    /// The preflow algorithm consists of two phases, this method runs

    /// the first phase. After the first phase the maximum flow value

    /// and a minimum value cut can already be computed, although a

    /// maximum flow is not yet obtained. So after calling this method

    /// \ref flowValue() returns the value of a maximum flow and \ref

    /// minCut() returns a minimum cut.

    /// \pre One of the \ref init() functions must be called before

    /// using this function.

    void startFirstPhase() {

      _phase = true;

      Node n = _level->highestActive();

      int level = _level->highestActiveLevel();

      while (n != INVALID) {

        int num = _node_num;

        while (num > 0 && n != INVALID) {

          Value excess = (*_excess)[n];

          int new_level = _level->maxLevel();

          for (OutArcIt e(_graph, n); e != INVALID; ++e) {

            Value rem = (*_capacity)[e] - (*_flow)[e];

            if (!_tolerance.positive(rem)) continue;

            Node v = _graph.target(e);

            if ((*_level)[v] < level) {

              if (!_level->active(v) && v != _target) {

                _level->activate(v);

              }

              if (!_tolerance.less(rem, excess)) {