LEMON/LEMON-main Changeset - r878:d6052a9c4e8d

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Changeset - r878:d6052a9c4e8d

« 844:a6eb96

880:b89e46 »

r878:d6052a9c4e8d

Thu, 18 Mar 2010 13:18:58

[Not Reviewed]

0 comments (0 inline)

alpar (Alpar Juttner)
alpar@cs.elte.hu

Backed out changeset a6eb9698c321 (#360, #51)

0 2 0

default

2 files changed with 4 insertions and 55 deletions:

lemon/bellman_ford.h

test/bellman_ford_test.cc

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lemon/bellman_ford.h

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 		/* -*- C++ -*-
+		 *
 		 * This file is a part of LEMON, a generic C++ optimization library
+		 *
 		 * Copyright (C) 2003-2008
 		 * 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.
+		 *
 		 */
 		#ifndef LEMON_BELLMAN_FORD_H
 		#define LEMON_BELLMAN_FORD_H
 		/// \ingroup shortest_path
 		/// \file
 		/// \brief Bellman-Ford algorithm.
 		#include <lemon/list_graph.h>
 		#include <lemon/bits/path_dump.h>
 		#include <lemon/core.h>
 		#include <lemon/error.h>
 		#include <lemon/maps.h>
 		#include <lemon/tolerance.h>
 		#include <lemon/path.h>
 		#include <limits>
 		namespace lemon {
-		  /// \brief Default operation traits for the BellmanFord algorithm class.
+		  /// \brief Default OperationTraits for the BellmanFord algorithm class.
 		  ///
 		  /// This operation traits class defines all computational operations
 		  /// and constants that are used in the Bellman-Ford algorithm.
 		  /// The default implementation is based on the \c numeric_limits class.
 		  /// If the numeric type does not have infinity value, then the maximum
 		  /// value is used as extremal infinity value.
 		  ///
 		  /// \see BellmanFordToleranceOperationTraits
 		  template <
 		    typename V,
 		    bool has_inf = std::numeric_limits<V>::has_infinity>
 		  struct BellmanFordDefaultOperationTraits {
-		    /// \brief Value type for the algorithm.
+		    /// \e
 		    typedef V Value;
 		    /// \brief Gives back the zero value of the type.
 		    static Value zero() {
 		      return static_cast<Value>(0);
+		    }
 		    /// \brief Gives back the positive infinity value of the type.
 		    static Value infinity() {
 		      return std::numeric_limits<Value>::infinity();
+		    }
 		    /// \brief Gives back the sum of the given two elements.
 		    static Value plus(const Value& left, const Value& right) {
 		      return left + right;
+		    }
 		    /// \brief Gives back \c true only if the first value is less than
 		    /// the second.
 		    static bool less(const Value& left, const Value& right) {
 		      return left < right;
+		    }
 		  };
 		  template <typename V>
 		  struct BellmanFordDefaultOperationTraits<V, false> {
 		    typedef V Value;
 		    static Value zero() {
 		      return static_cast<Value>(0);
+		    }
 		    static Value infinity() {
 		      return std::numeric_limits<Value>::max();
+		    }
 		    static Value plus(const Value& left, const Value& right) {
 		      if (left == infinity() || right == infinity()) return infinity();
 		      return left + right;
+		    }
 		    static bool less(const Value& left, const Value& right) {
 		      return left < right;
+		    }
 		  };
 		  /// \brief Operation traits for the BellmanFord algorithm class
 		  /// using tolerance.
 		  ///
 		  /// This operation traits class defines all computational operations
 		  /// and constants that are used in the Bellman-Ford algorithm.
 		  /// The only difference between this implementation and
 		  /// \ref BellmanFordDefaultOperationTraits is that this class uses
 		  /// the \ref Tolerance "tolerance technique" in its \ref less()
 		  /// function.
 		  ///
 		  /// \tparam V The value type.
 		  /// \tparam eps The epsilon value for the \ref less() function.
 		  /// By default, it is the epsilon value used by \ref Tolerance
 		  /// "Tolerance<V>".
 		  ///
 		  /// \see BellmanFordDefaultOperationTraits
 		#ifdef DOXYGEN
 		  template <typename V, V eps>
 		#else
 		  template <
 		    typename V,
 		    V eps = Tolerance<V>::def_epsilon>
 		#endif
 		  struct BellmanFordToleranceOperationTraits {
 		    /// \brief Value type for the algorithm.
 		    typedef V Value;
 		    /// \brief Gives back the zero value of the type.
 		    static Value zero() {
 		      return static_cast<Value>(0);
+		    }
 		    /// \brief Gives back the positive infinity value of the type.
 		    static Value infinity() {
 		      return std::numeric_limits<Value>::infinity();
+		    }
 		    /// \brief Gives back the sum of the given two elements.
 		    static Value plus(const Value& left, const Value& right) {
 		      return left + right;
+		    }
 		    /// \brief Gives back \c true only if the first value is less than
 		    /// the second.
 		    static bool less(const Value& left, const Value& right) {
 		      return left + eps < right;
+		    }
 		  };
 		  /// \brief Default traits class of BellmanFord class.
 		  ///
 		  /// Default traits class of BellmanFord class.
 		  /// \param GR The type of the digraph.
 		  /// \param LEN The type of the length map.
 		  template<typename GR, typename LEN>
 		  struct BellmanFordDefaultTraits {
 		    /// The type of the digraph the algorithm runs on.
 		    typedef GR Digraph;
 		    /// \brief The type of the map that stores the arc lengths.
 		    ///
 		    /// The type of the map that stores the arc lengths.
 		    /// It must conform to the \ref concepts::ReadMap "ReadMap" concept.
 		    typedef LEN LengthMap;
 		    /// The type of the arc lengths.
 		    typedef typename LEN::Value Value;
 		    /// \brief Operation traits for Bellman-Ford algorithm.
 		    ///
 		    /// It defines the used operations and the infinity value for the
 		    /// given \c Value type.
 		    /// \see BellmanFordDefaultOperationTraits,
 		    /// BellmanFordToleranceOperationTraits
 		    /// \see BellmanFordDefaultOperationTraits
 		    typedef BellmanFordDefaultOperationTraits<Value> OperationTraits;
 		    /// \brief The type of the map that stores the last arcs of the
 		    /// shortest paths.
 		    ///
 		    /// The type of the map that stores the last
 		    /// arcs of the shortest paths.
 		    /// It must conform to the \ref concepts::WriteMap "WriteMap" concept.
 		    typedef typename GR::template NodeMap<typename GR::Arc> PredMap;
 		    /// \brief Instantiates a \c PredMap.
 		    ///
 		    /// This function instantiates a \ref PredMap.
 		    /// \param g is the digraph to which we would like to define the
 		    /// \ref PredMap.
 		    static PredMap *createPredMap(const GR& g) {
 		      return new PredMap(g);
+		    }
 		    /// \brief The type of the map that stores the distances of the nodes.
 		    ///
 		    /// The type of the map that stores the distances of the nodes.
 		    /// It must conform to the \ref concepts::WriteMap "WriteMap" concept.
 		    typedef typename GR::template NodeMap<typename LEN::Value> DistMap;
 		    /// \brief Instantiates a \c DistMap.
 		    ///
 		    /// This function instantiates a \ref DistMap.
 		    /// \param g is the digraph to which we would like to define the
 		    /// \ref DistMap.
 		    static DistMap *createDistMap(const GR& g) {
 		      return new DistMap(g);
+		    }
 		  };
 		  /// \brief %BellmanFord algorithm class.
 		  ///
 		  /// \ingroup shortest_path
 		  /// This class provides an efficient implementation of the Bellman-Ford
 		  /// algorithm. The maximum time complexity of the algorithm is
 		  /// <tt>O(ne)</tt>.
 		  ///
 		  /// The Bellman-Ford algorithm solves the single-source shortest path
 		  /// problem when the arcs can have negative lengths, but the digraph
 		  /// should not contain directed cycles with negative total length.
 		  /// If all arc costs are non-negative, consider to use the Dijkstra
 		  /// algorithm instead, since it is more efficient.
 		  ///
 		  /// The arc lengths are passed to the algorithm using a
 		  /// \ref concepts::ReadMap "ReadMap", so it is easy to change it to any
 		  /// kind of length. The type of the length values is determined by the
 		  /// \ref concepts::ReadMap::Value "Value" type of the length map.
 		  ///
 		  /// There is also a \ref bellmanFord() "function-type interface" for the
 		  /// Bellman-Ford algorithm, which is convenient in the simplier cases and
 		  /// it can be used easier.
 		  ///
 		  /// \tparam GR The type of the digraph the algorithm runs on.
 		  /// The default type is \ref ListDigraph.
 		  /// \tparam LEN A \ref concepts::ReadMap "readable" arc map that specifies
 		  /// the lengths of the arcs. The default map type is
 		  /// \ref concepts::Digraph::ArcMap "GR::ArcMap<int>".
 		  /// \tparam TR The traits class that defines various types used by the
 		  /// algorithm. By default, it is \ref BellmanFordDefaultTraits
 		  /// "BellmanFordDefaultTraits<GR, LEN>".
 		  /// In most cases, this parameter should not be set directly,
 		  /// consider to use the named template parameters instead.
 		#ifdef DOXYGEN
 		  template <typename GR, typename LEN, typename TR>
 		#else
 		  template <typename GR=ListDigraph,
 		            typename LEN=typename GR::template ArcMap<int>,
 		            typename TR=BellmanFordDefaultTraits<GR,LEN> >
 		#endif
 		  class BellmanFord {
 		  public:
 		    ///The type of the underlying digraph.
 		    typedef typename TR::Digraph Digraph;
 		    /// \brief The type of the arc lengths.
 		    typedef typename TR::LengthMap::Value Value;
 		    /// \brief The type of the map that stores the arc lengths.
 		    typedef typename TR::LengthMap LengthMap;
 		    /// \brief The type of the map that stores the last
 		    /// arcs of the shortest paths.
 		    typedef typename TR::PredMap PredMap;
 		    /// \brief The type of the map that stores the distances of the nodes.
 		    typedef typename TR::DistMap DistMap;
 		    /// The type of the paths.
 		    typedef PredMapPath<Digraph, PredMap> Path;
 		    ///\brief The \ref BellmanFordDefaultOperationTraits
 		    /// "operation traits class" of the algorithm.
 		    typedef typename TR::OperationTraits OperationTraits;
 		    ///The \ref BellmanFordDefaultTraits "traits class" of the algorithm.
 		    typedef TR Traits;
 		  private:
 		    typedef typename Digraph::Node Node;
 		    typedef typename Digraph::NodeIt NodeIt;
 		    typedef typename Digraph::Arc Arc;
 		    typedef typename Digraph::OutArcIt OutArcIt;
 		    // Pointer to the underlying digraph.
 		    const Digraph *_gr;
 		    // Pointer to the length map
 		    const LengthMap *_length;
 		    // Pointer to the map of predecessors arcs.
 		    PredMap *_pred;
 		    // Indicates if _pred is locally allocated (true) or not.
 		    bool _local_pred;
 		    // Pointer to the map of distances.
 		    DistMap *_dist;
 		    // Indicates if _dist is locally allocated (true) or not.
 		    bool _local_dist;
 		    typedef typename Digraph::template NodeMap<bool> MaskMap;
 		    MaskMap *_mask;
 		    std::vector<Node> _process;
 		    // Creates the maps if necessary.
 		    void create_maps() {
 		      if(!_pred) {
 			_local_pred = true;
 			_pred = Traits::createPredMap(*_gr);
+		      }
 		      if(!_dist) {
 			_local_dist = true;
 			_dist = Traits::createDistMap(*_gr);
+		      }
 		      if(!_mask) {
 		        _mask = new MaskMap(*_gr);
+		      }
+		    }
 		  public :
 		    typedef BellmanFord Create;
 		    /// \name Named Template Parameters
 		    ///@{
 		    template <class T>
 		    struct SetPredMapTraits : public Traits {
 		      typedef T PredMap;
 		      static PredMap *createPredMap(const Digraph&) {
 		        LEMON_ASSERT(false, "PredMap is not initialized");
 		        return 0; // ignore warnings
+		      }
 		    };
 		    /// \brief \ref named-templ-param "Named parameter" for setting
 		    /// \c PredMap type.
 		    ///
 		    /// \ref named-templ-param "Named parameter" for setting
 		    /// \c PredMap type.
 		    /// It must conform to the \ref concepts::WriteMap "WriteMap" concept.
 		    template <class T>
 		    struct SetPredMap
 		      : public BellmanFord< Digraph, LengthMap, SetPredMapTraits<T> > {
 		      typedef BellmanFord< Digraph, LengthMap, SetPredMapTraits<T> > Create;
 		    };
 		    template <class T>
 		    struct SetDistMapTraits : public Traits {
 		      typedef T DistMap;
 		      static DistMap *createDistMap(const Digraph&) {
 		        LEMON_ASSERT(false, "DistMap is not initialized");
 		        return 0; // ignore warnings
+		      }
 		    };
 		    /// \brief \ref named-templ-param "Named parameter" for setting
 		    /// \c DistMap type.
 		    ///
 		    /// \ref named-templ-param "Named parameter" for setting
 		    /// \c DistMap type.
 		    /// It must conform to the \ref concepts::WriteMap "WriteMap" concept.
 		    template <class T>
 		    struct SetDistMap
 		      : public BellmanFord< Digraph, LengthMap, SetDistMapTraits<T> > {
 		      typedef BellmanFord< Digraph, LengthMap, SetDistMapTraits<T> > Create;
 		    };
 		    template <class T>
 		    struct SetOperationTraitsTraits : public Traits {
 		      typedef T OperationTraits;
 		    };
 		    /// \brief \ref named-templ-param "Named parameter" for setting
 		    /// \c OperationTraits type.
 		    ///
 		    /// \ref named-templ-param "Named parameter" for setting
 		    /// \c OperationTraits type.
 		    /// For more information, see \ref BellmanFordDefaultOperationTraits.
 		    template <class T>
 		    struct SetOperationTraits
 		      : public BellmanFord< Digraph, LengthMap, SetOperationTraitsTraits<T> > {
 		      typedef BellmanFord< Digraph, LengthMap, SetOperationTraitsTraits<T> >
 		      Create;
 		    };
 		    ///@}
 		  protected:
 		    BellmanFord() {}
 		  public:
 		    /// \brief Constructor.
 		    ///
 		    /// Constructor.
 		    /// \param g The digraph the algorithm runs on.
 		    /// \param length The length map used by the algorithm.
 		    BellmanFord(const Digraph& g, const LengthMap& length) :
 		      _gr(&g), _length(&length),
 		      _pred(0), _local_pred(false),
 		      _dist(0), _local_dist(false), _mask(0) {}
 		    ///Destructor.
 		    ~BellmanFord() {
 		      if(_local_pred) delete _pred;
 		      if(_local_dist) delete _dist;
 		      if(_mask) delete _mask;
+		    }
 		    /// \brief Sets the length map.
 		    ///
 		    /// Sets the length map.
 		    /// \return <tt>(*this)</tt>
 		    BellmanFord &lengthMap(const LengthMap &map) {
 		      _length = &map;
 		      return *this;
+		    }
 		    /// \brief Sets the map that stores the predecessor arcs.
 		    ///
 		    /// Sets the map that stores the predecessor arcs.
 		    /// 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>
 		    BellmanFord &predMap(PredMap &map) {
 		      if(_local_pred) {
 			delete _pred;
 			_local_pred=false;
+		      }
 		      _pred = &map;
 		      return *this;
+		    }
 		    /// \brief Sets the map that stores the distances of the nodes.
 		    ///
 		    /// Sets the map that stores the distances of the nodes calculated
 		    /// by the 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 map,
 		    /// of course.
 		    /// \return <tt>(*this)</tt>
 		    BellmanFord &distMap(DistMap &map) {
 		      if(_local_dist) {
 			delete _dist;
 			_local_dist=false;
+		      }
 		      _dist = &map;
 		      return *this;
+		    }
 		    /// \name Execution Control
 		    /// The simplest way to execute the Bellman-Ford algorithm is to use
 		    /// one of the member functions called \ref run().\n
 		    /// If you need better control on the execution, you have to call
 		    /// \ref init() first, then you can add several source nodes
 		    /// with \ref addSource(). Finally the actual path computation can be
 		    /// performed with \ref start(), \ref checkedStart() or
 		    /// \ref limitedStart().
 		    ///@{
 		    /// \brief Initializes the internal data structures.
 		    ///
 		    /// Initializes the internal data structures. The optional parameter
 		    /// is the initial distance of each node.
 		    void init(const Value value = OperationTraits::infinity()) {
 		      create_maps();
 		      for (NodeIt it(*_gr); it != INVALID; ++it) {
 			_pred->set(it, INVALID);
 			_dist->set(it, value);
+		      }
 		      _process.clear();
 		      if (OperationTraits::less(value, OperationTraits::infinity())) {
 			for (NodeIt it(*_gr); it != INVALID; ++it) {
 			  _process.push_back(it);
 			  _mask->set(it, true);
+			}
 		      } else {
 			for (NodeIt it(*_gr); it != INVALID; ++it) {
 			  _mask->set(it, false);
+			}
+		      }
+		    }
 		    /// \brief Adds a new source node.
 		    ///
 		    /// This function adds a new source node. The optional second parameter
 		    /// is the initial distance of the node.
 		    void addSource(Node source, Value dst = OperationTraits::zero()) {
 		      _dist->set(source, dst);
 		      if (!(*_mask)[source]) {
 			_process.push_back(source);
 			_mask->set(source, true);
+		      }
+		    }
 		    /// \brief Executes one round from the Bellman-Ford algorithm.
 		    ///
 		    /// If the algoritm calculated the distances in the previous round
 		    /// exactly for the paths of at most \c k arcs, then this function
 		    /// will calculate the distances exactly for the paths of at most
 		    /// <tt>k+1</tt> arcs. Performing \c k iterations using this function
 		    /// calculates the shortest path distances exactly for the paths
 		    /// consisting of at most \c k arcs.
 		    ///
 		    /// \warning The paths with limited arc number cannot be retrieved
 		    /// easily with \ref path() or \ref predArc() functions. If you also
 		    /// need the shortest paths and not only the distances, you should
 		    /// store the \ref predMap() "predecessor map" after each iteration
 		    /// and build the path manually.
 		    ///
 		    /// \return \c true when the algorithm have not found more shorter
 		    /// paths.
 		    ///
 		    /// \see ActiveIt
 		    bool processNextRound() {
 		      for (int i = 0; i < int(_process.size()); ++i) {
 			_mask->set(_process[i], false);
+		      }
 		      std::vector<Node> nextProcess;
 		      std::vector<Value> values(_process.size());
 		      for (int i = 0; i < int(_process.size()); ++i) {
 			values[i] = (*_dist)[_process[i]];
+		      }
 		      for (int i = 0; i < int(_process.size()); ++i) {
 			for (OutArcIt it(*_gr, _process[i]); it != INVALID; ++it) {
 			  Node target = _gr->target(it);
 			  Value relaxed = OperationTraits::plus(values[i], (*_length)[it]);
 			  if (OperationTraits::less(relaxed, (*_dist)[target])) {
 			    _pred->set(target, it);
 			    _dist->set(target, relaxed);
 			    if (!(*_mask)[target]) {
 			      _mask->set(target, true);
 			      nextProcess.push_back(target);
+			    }
+			  }
+			}
+		      }
 		      _process.swap(nextProcess);
 		      return _process.empty();
+		    }
 		    /// \brief Executes one weak round from the Bellman-Ford algorithm.
 		    ///
 		    /// If the algorithm calculated the distances in the previous round
 		    /// at least for the paths of at most \c k arcs, then this function
 		    /// will calculate the distances at least for the paths of at most
 		    /// <tt>k+1</tt> arcs.
 		    /// This function does not make it possible to calculate the shortest
 		    /// path distances exactly for paths consisting of at most \c k arcs,
 		    /// this is why it is called weak round.
 		    ///
 		    /// \return \c true when the algorithm have not found more shorter
 		    /// paths.
 		    ///
 		    /// \see ActiveIt
 		    bool processNextWeakRound() {
 		      for (int i = 0; i < int(_process.size()); ++i) {
 			_mask->set(_process[i], false);
+		      }
 		      std::vector<Node> nextProcess;
 		      for (int i = 0; i < int(_process.size()); ++i) {
 			for (OutArcIt it(*_gr, _process[i]); it != INVALID; ++it) {
 			  Node target = _gr->target(it);
 			  Value relaxed =
 			    OperationTraits::plus((*_dist)[_process[i]], (*_length)[it]);
 			  if (OperationTraits::less(relaxed, (*_dist)[target])) {
 			    _pred->set(target, it);
 			    _dist->set(target, relaxed);
 			    if (!(*_mask)[target]) {
 			      _mask->set(target, true);
 			      nextProcess.push_back(target);
+			    }
+			  }
+			}
+		      }
 		      _process.swap(nextProcess);
 		      return _process.empty();
+		    }
 		    /// \brief Executes the algorithm.
 		    ///
 		    /// Executes the algorithm.
 		    ///
 		    /// This method runs the Bellman-Ford algorithm from the root node(s)
 		    /// in order to compute the shortest path to each node.
 		    ///
 		    /// The algorithm computes
 		    /// - the shortest path tree (forest),
 		    /// - the distance of each node from the root(s).
 		    ///
 		    /// \pre init() must be called and at least one root node should be
 		    /// added with addSource() before using this function.
 		    void start() {
 		      int num = countNodes(*_gr) - 1;
 		      for (int i = 0; i < num; ++i) {
 			if (processNextWeakRound()) break;
+		      }
+		    }
 		    /// \brief Executes the algorithm and checks the negative cycles.
 		    ///
 		    /// Executes the algorithm and checks the negative cycles.
 		    ///
 		    /// This method runs the Bellman-Ford algorithm from the root node(s)
 		    /// in order to compute the shortest path to each node and also checks
 		    /// if the digraph contains cycles with negative total length.
 		    ///
 		    /// The algorithm computes
 		    /// - the shortest path tree (forest),
 		    /// - the distance of each node from the root(s).
 		    ///
 		    /// \return \c false if there is a negative cycle in the digraph.
 		    ///
 		    /// \pre init() must be called and at least one root node should be
 		    /// added with addSource() before using this function.
 		    bool checkedStart() {
 		      int num = countNodes(*_gr);
 		      for (int i = 0; i < num; ++i) {
 			if (processNextWeakRound()) return true;
+		      }
 		      return _process.empty();
+		    }
 		    /// \brief Executes the algorithm with arc number limit.
 		    ///
 		    /// Executes the algorithm with arc number limit.
 		    ///
 		    /// This method runs the Bellman-Ford algorithm from the root node(s)
 		    /// in order to compute the shortest path distance for each node
 		    /// using only the paths consisting of at most \c num arcs.
 		    ///
 		    /// The algorithm computes
 		    /// - the limited distance of each node from the root(s),
 		    /// - the predecessor arc for each node.
 		    ///
 		    /// \warning The paths with limited arc number cannot be retrieved
 		    /// easily with \ref path() or \ref predArc() functions. If you also
 		    /// need the shortest paths and not only the distances, you should
 		    /// store the \ref predMap() "predecessor map" after each iteration
 		    /// and build the path manually.
 		    ///
 		    /// \pre init() must be called and at least one root node should be
 		    /// added with addSource() before using this function.
 		    void limitedStart(int num) {
 		      for (int i = 0; i < num; ++i) {
 			if (processNextRound()) break;
+		      }
+		    }
 		    /// \brief Runs the algorithm from the given root node.
 		    ///
 		    /// This method runs the Bellman-Ford algorithm from the given root
 		    /// node \c s in order to compute the shortest path to each node.
 		    ///
 		    /// The algorithm computes
 		    /// - the shortest path tree (forest),
 		    /// - the distance of each node from the root(s).
 		    ///
 		    /// \note bf.run(s) is just a shortcut of the following code.
 		    /// \code
 		    ///   bf.init();
 		    ///   bf.addSource(s);
 		    ///   bf.start();
 		    /// \endcode
 		    void run(Node s) {
 		      init();
 		      addSource(s);
 		      start();
+		    }
 		    /// \brief Runs the algorithm from the given root node with arc
 		    /// number limit.
 		    ///
 		    /// This method runs the Bellman-Ford algorithm from the given root
 		    /// node \c s in order to compute the shortest path distance for each
 		    /// node using only the paths consisting of at most \c num arcs.
 		    ///
 		    /// The algorithm computes
 		    /// - the limited distance of each node from the root(s),
 		    /// - the predecessor arc for each node.
 		    ///
 		    /// \warning The paths with limited arc number cannot be retrieved
 		    /// easily with \ref path() or \ref predArc() functions. If you also
 		    /// need the shortest paths and not only the distances, you should
 		    /// store the \ref predMap() "predecessor map" after each iteration
 		    /// and build the path manually.
 		    ///
 		    /// \note bf.run(s, num) is just a shortcut of the following code.
 		    /// \code
 		    ///   bf.init();
 		    ///   bf.addSource(s);
 		    ///   bf.limitedStart(num);
 		    /// \endcode
 		    void run(Node s, int num) {
 		      init();
 		      addSource(s);
 		      limitedStart(num);
+		    }
 		    ///@}
 		    /// \brief LEMON iterator for getting the active nodes.
 		    ///
 		    /// This class provides a common style LEMON iterator that traverses
 		    /// the active nodes of the Bellman-Ford algorithm after the last
 		    /// phase. These nodes should be checked in the next phase to
 		    /// find augmenting arcs outgoing from them.
 		    class ActiveIt {
 		    public:
 		      /// \brief Constructor.
 		      ///
 		      /// Constructor for getting the active nodes of the given BellmanFord
 		      /// instance.
 		      ActiveIt(const BellmanFord& algorithm) : _algorithm(&algorithm)
+		      {
 		        _index = _algorithm->_process.size() - 1;
+		      }
 		      /// \brief Invalid constructor.
 		      ///
 		      /// Invalid constructor.
 		      ActiveIt(Invalid) : _algorithm(0), _index(-1) {}
 		      /// \brief Conversion to \c Node.
 		      ///
 		      /// Conversion to \c Node.
 		      operator Node() const {
 		        return _index >= 0 ? _algorithm->_process[_index] : INVALID;
+		      }
 		      /// \brief Increment operator.
 		      ///
 		      /// Increment operator.
 		      ActiveIt& operator++() {
 		        --_index;
 		        return *this;
+		      }
 		      bool operator==(const ActiveIt& it) const {
 		        return static_cast<Node>(*this) == static_cast<Node>(it);
+		      }
 		      bool operator!=(const ActiveIt& it) const {
 		        return static_cast<Node>(*this) != static_cast<Node>(it);
+		      }
 		      bool operator<(const ActiveIt& it) const {
 		        return static_cast<Node>(*this) < static_cast<Node>(it);
+		      }
 		    private:
 		      const BellmanFord* _algorithm;
 		      int _index;
 		    };
 		    /// \name Query Functions
 		    /// The result of the Bellman-Ford algorithm can be obtained using these
 		    /// functions.\n
 		    /// Either \ref run() or \ref init() should be called before using them.
 		    ///@{
 		    /// \brief The shortest path to the given node.
 		    ///
 		    /// Gives back the shortest path to the given node from the root(s).
 		    ///
 		    /// \warning \c t should be reached from the root(s).
 		    ///
 		    /// \pre Either \ref run() or \ref init() must be called before
 		    /// using this function.
 		    Path path(Node t) const
+		    {
 		      return Path(*_gr, *_pred, t);
+		    }
 		    /// \brief The distance of the given node from the root(s).
 		    ///
 		    /// Returns the distance of the given node from the root(s).
 		    ///
 		    /// \warning If node \c v is not reached from the root(s), then
 		    /// the return value of this function is undefined.
 		    ///
 		    /// \pre Either \ref run() or \ref init() must be called before
 		    /// using this function.
 		    Value dist(Node v) const { return (*_dist)[v]; }
 		    /// \brief Returns the 'previous arc' of the shortest path tree for
 		    /// the given node.
 		    ///
 		    /// This function returns the 'previous arc' of the shortest path
 		    /// tree for node \c v, i.e. it returns the last arc of a
 		    /// shortest path from a root to \c v. It is \c INVALID if \c v
 		    /// is not reached from the root(s) or if \c v is a root.
 		    ///
 		    /// The shortest path tree used here is equal to the shortest path
 		    /// tree used in \ref predNode() and \ref predMap().
 		    ///
 		    /// \pre Either \ref run() or \ref init() must be called before
 		    /// using this function.
 		    Arc predArc(Node v) const { return (*_pred)[v]; }
 		    /// \brief Returns the 'previous node' of the shortest path tree for
 		    /// the given node.
 		    ///
 		    /// This function returns the 'previous node' of the shortest path
 		    /// tree for node \c v, i.e. it returns the last but one node of
 		    /// a shortest path from a root to \c v. It is \c INVALID if \c v
 		    /// is not reached from the root(s) or if \c v is a root.
 		    ///
 		    /// The shortest path tree used here is equal to the shortest path
 		    /// tree used in \ref predArc() and \ref predMap().
 		    ///
 		    /// \pre Either \ref run() or \ref init() must be called before
 		    /// using this function.
 		    Node predNode(Node v) const {
 		      return (*_pred)[v] == INVALID ? INVALID : _gr->source((*_pred)[v]);
+		    }
 		    /// \brief Returns a const reference to the node map that stores the
 		    /// distances of the nodes.
 		    ///
 		    /// Returns a const reference to the node map that stores the distances
 		    /// of the nodes calculated by the algorithm.
 		    ///
 		    /// \pre Either \ref run() or \ref init() must be called before
 		    /// using this function.
 		    const DistMap &distMap() const { return *_dist;}
 		    /// \brief Returns a const reference to the node map that stores the
 		    /// predecessor arcs.
 		    ///
 		    /// Returns a const reference to the node map that stores the predecessor
 		    /// arcs, which form the shortest path tree (forest).
 		    ///
 		    /// \pre Either \ref run() or \ref init() must be called before
 		    /// using this function.
 		    const PredMap &predMap() const { return *_pred; }
 		    /// \brief Checks if a node is reached from the root(s).
 		    ///
 		    /// Returns \c true if \c v is reached from the root(s).
 		    ///
 		    /// \pre Either \ref run() or \ref init() must be called before
 		    /// using this function.
 		    bool reached(Node v) const {
 		      return (*_dist)[v] != OperationTraits::infinity();
+		    }
 		    /// \brief Gives back a negative cycle.
 		    ///
 		    /// This function gives back a directed cycle with negative total
 		    /// length if the algorithm has already found one.
 		    /// Otherwise it gives back an empty path.
 		    lemon::Path<Digraph> negativeCycle() const {
 		      typename Digraph::template NodeMap<int> state(*_gr, -1);
 		      lemon::Path<Digraph> cycle;
 		      for (int i = 0; i < int(_process.size()); ++i) {
 		        if (state[_process[i]] != -1) continue;
 		        for (Node v = _process[i]; (*_pred)[v] != INVALID;
 		             v = _gr->source((*_pred)[v])) {
 		          if (state[v] == i) {
 		            cycle.addFront((*_pred)[v]);
 		            for (Node u = _gr->source((*_pred)[v]); u != v;
 		                 u = _gr->source((*_pred)[u])) {
 		              cycle.addFront((*_pred)[u]);
+		            }
 		            return cycle;
+		          }
 		          else if (state[v] >= 0) {
 		            break;
+		          }
 		          state[v] = i;
+		        }
+		      }
 		      return cycle;
+		    }
 		    ///@}
 		  };
 		  /// \brief Default traits class of bellmanFord() function.
 		  ///
 		  /// Default traits class of bellmanFord() function.
 		  /// \tparam GR The type of the digraph.
 		  /// \tparam LEN The type of the length map.
 		  template <typename GR, typename LEN>
 		  struct BellmanFordWizardDefaultTraits {
 		    /// The type of the digraph the algorithm runs on.
 		    typedef GR Digraph;
 		    /// \brief The type of the map that stores the arc lengths.
 		    ///
 		    /// The type of the map that stores the arc lengths.
 		    /// It must meet the \ref concepts::ReadMap "ReadMap" concept.
 		    typedef LEN LengthMap;
 		    /// The type of the arc lengths.
 		    typedef typename LEN::Value Value;
 		    /// \brief Operation traits for Bellman-Ford algorithm.
 		    ///
 		    /// It defines the used operations and the infinity value for the
 		    /// given \c Value type.
 		    /// \see BellmanFordDefaultOperationTraits,
 		    /// BellmanFordToleranceOperationTraits
 		    /// \see BellmanFordDefaultOperationTraits
 		    typedef BellmanFordDefaultOperationTraits<Value> OperationTraits;
 		    /// \brief The type of the map that stores the last
 		    /// arcs of the shortest paths.
 		    ///
 		    /// The type of the map that stores the last arcs of the shortest paths.
 		    /// It must conform to the \ref concepts::WriteMap "WriteMap" concept.
 		    typedef typename GR::template NodeMap<typename GR::Arc> PredMap;
 		    /// \brief Instantiates a \c PredMap.
 		    ///
 		    /// This function instantiates a \ref PredMap.
 		    /// \param g is the digraph to which we would like to define the
 		    /// \ref PredMap.
 		    static PredMap *createPredMap(const GR &g) {
 		      return new PredMap(g);
+		    }
 		    /// \brief The type of the map that stores the distances of the nodes.
 		    ///
 		    /// The type of the map that stores the distances of the nodes.
 		    /// It must conform to the \ref concepts::WriteMap "WriteMap" concept.
 		    typedef typename GR::template NodeMap<Value> DistMap;
 		    /// \brief Instantiates a \c DistMap.
 		    ///
 		    /// This function instantiates a \ref DistMap.
 		    /// \param g is the digraph to which we would like to define the
 		    /// \ref DistMap.
 		    static DistMap *createDistMap(const GR &g) {
 		      return new DistMap(g);
+		    }
 		    ///The type of the shortest paths.
 		    ///The type of the shortest paths.
 		    ///It must meet the \ref concepts::Path "Path" concept.
 		    typedef lemon::Path<Digraph> Path;
 		  };
 		  /// \brief Default traits class used by BellmanFordWizard.
 		  ///
 		  /// Default traits class used by BellmanFordWizard.
 		  /// \tparam GR The type of the digraph.
 		  /// \tparam LEN The type of the length map.
 		  template <typename GR, typename LEN>
 		  class BellmanFordWizardBase
 		    : public BellmanFordWizardDefaultTraits<GR, LEN> {
 		    typedef BellmanFordWizardDefaultTraits<GR, LEN> Base;
 		  protected:
 		    // Type of the nodes in the digraph.
 		    typedef typename Base::Digraph::Node Node;
 		    // Pointer to the underlying digraph.
 		    void *_graph;
 		    // Pointer to the length map
 		    void *_length;
 		    // Pointer to the map of predecessors arcs.
 		    void *_pred;
 		    // Pointer to the map of distances.
 		    void *_dist;
 		    //Pointer to the shortest path to the target node.
 		    void *_path;
 		    //Pointer to the distance of the target node.
 		    void *_di;
 		    public:
 		    /// Constructor.
 		    /// This constructor does not require parameters, it initiates
 		    /// all of the attributes to default values \c 0.
 		    BellmanFordWizardBase() :
 		      _graph(0), _length(0), _pred(0), _dist(0), _path(0), _di(0) {}
 		    /// Constructor.
 		    /// This constructor requires two parameters,
 		    /// others are initiated to \c 0.
 		    /// \param gr The digraph the algorithm runs on.
 		    /// \param len The length map.
 		    BellmanFordWizardBase(const GR& gr,
 					  const LEN& len) :
 		      _graph(reinterpret_cast<void*>(const_cast<GR*>(&gr))),
 		      _length(reinterpret_cast<void*>(const_cast<LEN*>(&len))),
 		      _pred(0), _dist(0), _path(0), _di(0) {}
 		  };
 		  /// \brief Auxiliary class for the function-type interface of the
 		  /// \ref BellmanFord "Bellman-Ford" algorithm.
 		  ///
 		  /// This auxiliary class is created to implement the
 		  /// \ref bellmanFord() "function-type interface" of the
 		  /// \ref BellmanFord "Bellman-Ford" algorithm.
 		  /// It does not have own \ref run() method, it uses the
 		  /// functions and features of the plain \ref BellmanFord.
 		  ///
 		  /// This class should only be used through the \ref bellmanFord()
 		  /// function, which makes it easier to use the algorithm.
 		  ///
 		  /// \tparam TR The traits class that defines various types used by the
 		  /// algorithm.
 		  template<class TR>
 		  class BellmanFordWizard : public TR {
 		    typedef TR Base;
 		    typedef typename TR::Digraph Digraph;
 		    typedef typename Digraph::Node Node;
 		    typedef typename Digraph::NodeIt NodeIt;
 		    typedef typename Digraph::Arc Arc;
 		    typedef typename Digraph::OutArcIt ArcIt;
 		    typedef typename TR::LengthMap LengthMap;
 		    typedef typename LengthMap::Value Value;
 		    typedef typename TR::PredMap PredMap;
 		    typedef typename TR::DistMap DistMap;
 		    typedef typename TR::Path Path;
 		  public:
 		    /// Constructor.
 		    BellmanFordWizard() : TR() {}
 		    /// \brief Constructor that requires parameters.
 		    ///
 		    /// Constructor that requires parameters.
 		    /// These parameters will be the default values for the traits class.
 		    /// \param gr The digraph the algorithm runs on.
 		    /// \param len The length map.
 		    BellmanFordWizard(const Digraph& gr, const LengthMap& len)
 		      : TR(gr, len) {}
 		    /// \brief Copy constructor
 		    BellmanFordWizard(const TR &b) : TR(b) {}
 		    ~BellmanFordWizard() {}
 		    /// \brief Runs the Bellman-Ford algorithm from the given source node.
 		    ///
 		    /// This method runs the Bellman-Ford algorithm from the given source
 		    /// node in order to compute the shortest path to each node.
 		    void run(Node s) {
 		      BellmanFord<Digraph,LengthMap,TR>
 			bf(*reinterpret_cast<const Digraph*>(Base::_graph),
 		           *reinterpret_cast<const LengthMap*>(Base::_length));
 		      if (Base::_pred) bf.predMap(*reinterpret_cast<PredMap*>(Base::_pred));
 		      if (Base::_dist) bf.distMap(*reinterpret_cast<DistMap*>(Base::_dist));
 		      bf.run(s);
+		    }
 		    /// \brief Runs the Bellman-Ford algorithm to find the shortest path
 		    /// between \c s and \c t.
 		    ///
 		    /// This method runs the Bellman-Ford algorithm from node \c s
 		    /// in order to compute the shortest path to node \c t.
 		    /// Actually, it computes the shortest path to each node, but using
 		    /// this function you can retrieve the distance and the shortest path
 		    /// for a single target node easier.
 		    ///
 		    /// \return \c true if \c t is reachable form \c s.
 		    bool run(Node s, Node t) {
 		      BellmanFord<Digraph,LengthMap,TR>
 		        bf(*reinterpret_cast<const Digraph*>(Base::_graph),
 		           *reinterpret_cast<const LengthMap*>(Base::_length));
 		      if (Base::_pred) bf.predMap(*reinterpret_cast<PredMap*>(Base::_pred));
 		      if (Base::_dist) bf.distMap(*reinterpret_cast<DistMap*>(Base::_dist));
 		      bf.run(s);
 		      if (Base::_path) *reinterpret_cast<Path*>(Base::_path) = bf.path(t);
 		      if (Base::_di) *reinterpret_cast<Value*>(Base::_di) = bf.dist(t);
 		      return bf.reached(t);
+		    }
 		    template<class T>
 		    struct SetPredMapBase : public Base {
 		      typedef T PredMap;
 		      static PredMap *createPredMap(const Digraph &) { return 0; };
 		      SetPredMapBase(const TR &b) : TR(b) {}
 		    };
 		    /// \brief \ref named-templ-param "Named parameter" for setting
 		    /// the predecessor map.
 		    ///
 		    /// \ref named-templ-param "Named parameter" for setting
 		    /// the map that stores the predecessor arcs of the nodes.
 		    template<class T>
 		    BellmanFordWizard<SetPredMapBase<T> > predMap(const T &t) {
 		      Base::_pred=reinterpret_cast<void*>(const_cast<T*>(&t));
 		      return BellmanFordWizard<SetPredMapBase<T> >(*this);
+		    }
 		    template<class T>
 		    struct SetDistMapBase : public Base {
 		      typedef T DistMap;
 		      static DistMap *createDistMap(const Digraph &) { return 0; };
 		      SetDistMapBase(const TR &b) : TR(b) {}
 		    };
 		    /// \brief \ref named-templ-param "Named parameter" for setting
 		    /// the distance map.
 		    ///
 		    /// \ref named-templ-param "Named parameter" for setting
 		    /// the map that stores the distances of the nodes calculated
 		    /// by the algorithm.
 		    template<class T>
 		    BellmanFordWizard<SetDistMapBase<T> > distMap(const T &t) {
 		      Base::_dist=reinterpret_cast<void*>(const_cast<T*>(&t));
 		      return BellmanFordWizard<SetDistMapBase<T> >(*this);
+		    }
 		    template<class T>
 		    struct SetPathBase : public Base {
 		      typedef T Path;
 		      SetPathBase(const TR &b) : TR(b) {}
 		    };
 		    /// \brief \ref named-func-param "Named parameter" for getting
 		    /// the shortest path to the target node.
 		    ///
 		    /// \ref named-func-param "Named parameter" for getting
 		    /// the shortest path to the target node.
 		    template<class T>
 		    BellmanFordWizard<SetPathBase<T> > path(const T &t)
+		    {
 		      Base::_path=reinterpret_cast<void*>(const_cast<T*>(&t));
 		      return BellmanFordWizard<SetPathBase<T> >(*this);
+		    }
 		    /// \brief \ref named-func-param "Named parameter" for getting
 		    /// the distance of the target node.
 		    ///
 		    /// \ref named-func-param "Named parameter" for getting
 		    /// the distance of the target node.
 		    BellmanFordWizard dist(const Value &d)
+		    {
 		      Base::_di=reinterpret_cast<void*>(const_cast<Value*>(&d));
 		      return *this;
+		    }
 		  };
 		  /// \brief Function type interface for the \ref BellmanFord "Bellman-Ford"
 		  /// algorithm.
 		  ///
 		  /// \ingroup shortest_path
 		  /// Function type interface for the \ref BellmanFord "Bellman-Ford"
 		  /// algorithm.
 		  ///
 		  /// This function also has several \ref named-templ-func-param
 		  /// "named parameters", they are declared as the members of class
 		  /// \ref BellmanFordWizard.
 		  /// The following examples show how to use these parameters.
 		  /// \code
 		  ///   // Compute shortest path from node s to each node
 		  ///   bellmanFord(g,length).predMap(preds).distMap(dists).run(s);
 		  ///
 		  ///   // Compute shortest path from s to t
 		  ///   bool reached = bellmanFord(g,length).path(p).dist(d).run(s,t);
 		  /// \endcode
 		  /// \warning Don't forget to put the \ref BellmanFordWizard::run() "run()"
 		  /// to the end of the parameter list.
 		  /// \sa BellmanFordWizard
 		  /// \sa BellmanFord
 		  template<typename GR, typename LEN>
 		  BellmanFordWizard<BellmanFordWizardBase<GR,LEN> >
 		  bellmanFord(const GR& digraph,
 			      const LEN& length)
+		  {
 		    return BellmanFordWizard<BellmanFordWizardBase<GR,LEN> >(digraph, length);
+		  }
 		} //END OF NAMESPACE LEMON
 		#endif

test/bellman_ford_test.cc

Show inline comments

 		/* -*- mode: C++; indent-tabs-mode: nil; -*-
+		 *
 		 * This file is a part of LEMON, a generic C++ optimization library.
+		 *
 		 * Copyright (C) 2003-2009
 		 * 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.
+		 *
 		 */
 		#include <lemon/concepts/digraph.h>
 		#include <lemon/smart_graph.h>
 		#include <lemon/list_graph.h>
 		#include <lemon/lgf_reader.h>
 		#include <lemon/bellman_ford.h>
 		#include <lemon/path.h>
 		#include "graph_test.h"
 		#include "test_tools.h"
 		using namespace lemon;
 		char test_lgf[] =
 		  "@nodes\n"
 		  "label\n"
 		  "0\n"
 		  "1\n"
 		  "2\n"
 		  "3\n"
 		  "4\n"
 		  "@arcs\n"
 		  "    length\n"
 		  "0 1 3\n"
 		  "1 2 -3\n"
 		  "1 2 -5\n"
 		  "1 3 -2\n"
 		  "0 2 -1\n"
 		  "1 2 -4\n"
 		  "0 3 2\n"
 		  "4 2 -5\n"
 		  "2 3 1\n"
 		  "@attributes\n"
 		  "source 0\n"
 		  "target 3\n";
 		void checkBellmanFordCompile()
+		{
 		  typedef int Value;
 		  typedef concepts::Digraph Digraph;
 		  typedef concepts::ReadMap<Digraph::Arc,Value> LengthMap;
 		  typedef BellmanFord<Digraph, LengthMap> BF;
 		  typedef Digraph::Node Node;
 		  typedef Digraph::Arc Arc;
 		  Digraph gr;
 		  Node s, t, n;
 		  Arc e;
 		  Value l;
 		  int k=3;
 		  bool b;
 		  BF::DistMap d(gr);
 		  BF::PredMap p(gr);
 		  LengthMap length;
 		  concepts::Path<Digraph> pp;
+		  {
 		    BF bf_test(gr,length);
 		    const BF& const_bf_test = bf_test;
 		    bf_test.run(s);
 		    bf_test.run(s,k);
 		    bf_test.init();
 		    bf_test.addSource(s);
 		    bf_test.addSource(s, 1);
 		    b = bf_test.processNextRound();
 		    b = bf_test.processNextWeakRound();
 		    bf_test.start();
 		    bf_test.checkedStart();
 		    bf_test.limitedStart(k);
 		    l  = const_bf_test.dist(t);
 		    e  = const_bf_test.predArc(t);
 		    s  = const_bf_test.predNode(t);
 		    b  = const_bf_test.reached(t);
 		    d  = const_bf_test.distMap();
 		    p  = const_bf_test.predMap();
 		    pp = const_bf_test.path(t);
 		    pp = const_bf_test.negativeCycle();
 		    for (BF::ActiveIt it(const_bf_test); it != INVALID; ++it) {}
+		  }
+		  {
 		    BF::SetPredMap<concepts::ReadWriteMap<Node,Arc> >
 		      ::SetDistMap<concepts::ReadWriteMap<Node,Value> >
 		      ::SetOperationTraits<BellmanFordDefaultOperationTraits<Value> >
 		      ::SetOperationTraits<BellmanFordToleranceOperationTraits<Value, 0> >
 		      ::Create bf_test(gr,length);
 		    LengthMap length_map;
 		    concepts::ReadWriteMap<Node,Arc> pred_map;
 		    concepts::ReadWriteMap<Node,Value> dist_map;
 		    bf_test
 		      .lengthMap(length_map)
 		      .predMap(pred_map)
 		      .distMap(dist_map);
 		    bf_test.run(s);
 		    bf_test.run(s,k);
 		    bf_test.init();
 		    bf_test.addSource(s);
 		    bf_test.addSource(s, 1);
 		    b = bf_test.processNextRound();
 		    b = bf_test.processNextWeakRound();
 		    bf_test.start();
 		    bf_test.checkedStart();
 		    bf_test.limitedStart(k);
 		    l  = bf_test.dist(t);
 		    e  = bf_test.predArc(t);
 		    s  = bf_test.predNode(t);
 		    b  = bf_test.reached(t);
 		    pp = bf_test.path(t);
 		    pp = bf_test.negativeCycle();
+		  }
+		}
 		void checkBellmanFordFunctionCompile()
+		{
 		  typedef int Value;
 		  typedef concepts::Digraph Digraph;
 		  typedef Digraph::Arc Arc;
 		  typedef Digraph::Node Node;
 		  typedef concepts::ReadMap<Digraph::Arc,Value> LengthMap;
 		  Digraph g;
 		  bool b;
 		  bellmanFord(g,LengthMap()).run(Node());
 		  b = bellmanFord(g,LengthMap()).run(Node(),Node());
 		  bellmanFord(g,LengthMap())
 		    .predMap(concepts::ReadWriteMap<Node,Arc>())
 		    .distMap(concepts::ReadWriteMap<Node,Value>())
 		    .run(Node());
 		  b=bellmanFord(g,LengthMap())
 		    .predMap(concepts::ReadWriteMap<Node,Arc>())
 		    .distMap(concepts::ReadWriteMap<Node,Value>())
 		    .path(concepts::Path<Digraph>())
 		    .dist(Value())
 		    .run(Node(),Node());
+		}
 		template <typename Digraph, typename Value>
 		void checkBellmanFord() {
 		  TEMPLATE_DIGRAPH_TYPEDEFS(Digraph);
 		  typedef typename Digraph::template ArcMap<Value> LengthMap;
 		  Digraph gr;
 		  Node s, t;
 		  LengthMap length(gr);
 		  std::istringstream input(test_lgf);
 		  digraphReader(gr, input).
 		    arcMap("length", length).
 		    node("source", s).
 		    node("target", t).
 		    run();
 		  BellmanFord<Digraph, LengthMap>
 		    bf(gr, length);
 		  bf.run(s);
 		  Path<Digraph> p = bf.path(t);
 		  check(bf.reached(t) && bf.dist(t) == -1, "Bellman-Ford found a wrong path.");
 		  check(p.length() == 3, "path() found a wrong path.");
 		  check(checkPath(gr, p), "path() found a wrong path.");
 		  check(pathSource(gr, p) == s, "path() found a wrong path.");
 		  check(pathTarget(gr, p) == t, "path() found a wrong path.");
 		  ListPath<Digraph> path;
 		  Value dist;
 		  bool reached = bellmanFord(gr,length).path(path).dist(dist).run(s,t);
 		  check(reached && dist == -1, "Bellman-Ford found a wrong path.");
 		  check(path.length() == 3, "path() found a wrong path.");
 		  check(checkPath(gr, path), "path() found a wrong path.");
 		  check(pathSource(gr, path) == s, "path() found a wrong path.");
 		  check(pathTarget(gr, path) == t, "path() found a wrong path.");
 		  for(ArcIt e(gr); e!=INVALID; ++e) {
 		    Node u=gr.source(e);
 		    Node v=gr.target(e);
 		    check(!bf.reached(u) || (bf.dist(v) - bf.dist(u) <= length[e]),
 		          "Wrong output. dist(target)-dist(source)-arc_length=" <<
 		          bf.dist(v) - bf.dist(u) - length[e]);
+		  }
 		  for(NodeIt v(gr); v!=INVALID; ++v) {
 		    if (bf.reached(v)) {
 		      check(v==s || bf.predArc(v)!=INVALID, "Wrong tree.");
 		      if (bf.predArc(v)!=INVALID ) {
 		        Arc e=bf.predArc(v);
 		        Node u=gr.source(e);
 		        check(u==bf.predNode(v),"Wrong tree.");
 		        check(bf.dist(v) - bf.dist(u) == length[e],
 		              "Wrong distance! Difference: " <<
 		              bf.dist(v) - bf.dist(u) - length[e]);
+		      }
+		    }
+		  }
+		}
 		void checkBellmanFordNegativeCycle() {
 		  DIGRAPH_TYPEDEFS(SmartDigraph);
 		  SmartDigraph gr;
 		  IntArcMap length(gr);
 		  Node n1 = gr.addNode();
 		  Node n2 = gr.addNode();
 		  Node n3 = gr.addNode();
 		  Node n4 = gr.addNode();
 		  Arc a1 = gr.addArc(n1, n2);
 		  Arc a2 = gr.addArc(n2, n2);
 		  length[a1] = 2;
 		  length[a2] = -1;
+		  {
 		    BellmanFord<SmartDigraph, IntArcMap> bf(gr, length);
 		    bf.run(n1);
 		    StaticPath<SmartDigraph> p = bf.negativeCycle();
 		    check(p.length() == 1 && p.front() == p.back() && p.front() == a2,
 		          "Wrong negative cycle.");
+		  }
 		  length[a2] = 0;
+		  {
 		    BellmanFord<SmartDigraph, IntArcMap> bf(gr, length);
 		    bf.run(n1);
 		    check(bf.negativeCycle().empty(),
 		          "Negative cycle should not be found.");
+		  }
 		  length[gr.addArc(n1, n3)] = 5;
 		  length[gr.addArc(n4, n3)] = 1;
 		  length[gr.addArc(n2, n4)] = 2;
 		  length[gr.addArc(n3, n2)] = -4;
+		  {
 		    BellmanFord<SmartDigraph, IntArcMap> bf(gr, length);
 		    bf.init();
 		    bf.addSource(n1);
 		    for (int i = 0; i < 4; ++i) {
 		      check(bf.negativeCycle().empty(),
 		            "Negative cycle should not be found.");
 		      bf.processNextRound();
+		    }
 		    StaticPath<SmartDigraph> p = bf.negativeCycle();
 		    check(p.length() == 3, "Wrong negative cycle.");
 		    check(length[p.nth(0)] + length[p.nth(1)] + length[p.nth(2)] == -1,
 		          "Wrong negative cycle.");
+		  }
+		}
 		int main() {
 		  checkBellmanFord<ListDigraph, int>();
 		  checkBellmanFord<SmartDigraph, double>();
 		  checkBellmanFordNegativeCycle();
 		  return 0;
+		}

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