diff --git a/lemon/bfs.h b/lemon/bfs.h --- a/lemon/bfs.h +++ b/lemon/bfs.h @@ -21,7 +21,7 @@ ///\ingroup search ///\file -///\brief Bfs algorithm. +///\brief BFS algorithm. #include #include @@ -31,8 +31,6 @@ namespace lemon { - - ///Default traits class of Bfs class. ///Default traits class of Bfs class. @@ -40,73 +38,75 @@ template struct BfsDefaultTraits { - ///The digraph type the algorithm runs on. + ///The type of the digraph the algorithm runs on. typedef GR Digraph; - ///\brief The type of the map that stores the last + + ///\brief The type of the map that stores the predecessor ///arcs of the shortest paths. /// - ///The type of the map that stores the last + ///The type of the map that stores the predecessor ///arcs of the shortest paths. ///It must meet the \ref concepts::WriteMap "WriteMap" concept. - /// - typedef typename Digraph::template NodeMap PredMap; - ///Instantiates a PredMap. + typedef typename Digraph::template NodeMap PredMap; + ///Instantiates a \ref PredMap. ///This function instantiates a \ref PredMap. - ///\param G is the digraph, to which we would like to define the PredMap. + ///\param g is the digraph, to which we would like to define the + ///\ref PredMap. ///\todo The digraph alone may be insufficient to initialize - static PredMap *createPredMap(const GR &G) + static PredMap *createPredMap(const Digraph &g) { - return new PredMap(G); + return new PredMap(g); } + ///The type of the map that indicates which nodes are processed. ///The type of the map that indicates which nodes are processed. ///It must meet the \ref concepts::WriteMap "WriteMap" concept. - ///\todo named parameter to set this type, function to read and write. + ///By default it is a NullMap. typedef NullMap ProcessedMap; - ///Instantiates a ProcessedMap. + ///Instantiates a \ref ProcessedMap. ///This function instantiates a \ref ProcessedMap. ///\param g is the digraph, to which ///we would like to define the \ref ProcessedMap #ifdef DOXYGEN - static ProcessedMap *createProcessedMap(const GR &g) + static ProcessedMap *createProcessedMap(const Digraph &g) #else - static ProcessedMap *createProcessedMap(const GR &) + static ProcessedMap *createProcessedMap(const Digraph &) #endif { return new ProcessedMap(); } + ///The type of the map that indicates which nodes are reached. ///The type of the map that indicates which nodes are reached. - ///It must meet the \ref concepts::WriteMap "WriteMap" concept. - ///\todo named parameter to set this type, function to read and write. + ///It must meet the \ref concepts::ReadWriteMap "ReadWriteMap" concept. typedef typename Digraph::template NodeMap ReachedMap; - ///Instantiates a ReachedMap. + ///Instantiates a \ref ReachedMap. ///This function instantiates a \ref ReachedMap. - ///\param G is the digraph, to which + ///\param g is the digraph, to which ///we would like to define the \ref ReachedMap. - static ReachedMap *createReachedMap(const GR &G) + static ReachedMap *createReachedMap(const Digraph &g) { - return new ReachedMap(G); + return new ReachedMap(g); } - ///The type of the map that stores the dists of the nodes. - ///The type of the map that stores the dists of the nodes. + ///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 meet the \ref concepts::WriteMap "WriteMap" concept. - /// typedef typename Digraph::template NodeMap DistMap; - ///Instantiates a DistMap. + ///Instantiates a \ref 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) + ///\param g is the digraph, to which we would like to define the + ///\ref DistMap. + static DistMap *createDistMap(const Digraph &g) { - return new DistMap(G); + return new DistMap(g); } }; @@ -115,15 +115,18 @@ ///\ingroup search ///This class provides an efficient implementation of the %BFS algorithm. /// - ///\tparam GR The digraph type the algorithm runs on. The default value is - ///\ref ListDigraph. The value of GR is not used directly by Bfs, it - ///is only passed to \ref BfsDefaultTraits. + ///There is also a \ref bfs() "function type interface" for the BFS + ///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 value is \ref ListDigraph. The value of GR is not used + ///directly by \ref Bfs, it is only passed to \ref BfsDefaultTraits. ///\tparam TR Traits class to set various data types used by the algorithm. ///The default traits class is ///\ref BfsDefaultTraits "BfsDefaultTraits". ///See \ref BfsDefaultTraits for the documentation of ///a Bfs traits class. - #ifdef DOXYGEN template @@ -133,12 +136,10 @@ #endif class Bfs { public: - /** - * \brief \ref Exception for uninitialized parameters. - * - * This error represents problems in the initialization - * of the parameters of the algorithms. - */ + ///\ref Exception for uninitialized parameters. + + ///This error represents problems in the initialization of the + ///parameters of the algorithm. class UninitializedParameter : public lemon::UninitializedParameter { public: virtual const char* what() const throw() { @@ -146,19 +147,24 @@ } }; - typedef TR Traits; - ///The type of the underlying digraph. + ///The type of the digraph the algorithm runs on. typedef typename TR::Digraph Digraph; - ///\brief The type of the map that stores the last - ///arcs of the shortest paths. + ///\brief The type of the map that stores the predecessor arcs of the + ///shortest paths. typedef typename TR::PredMap PredMap; - ///The type of the map indicating which nodes are reached. + ///The type of the map that stores the distances of the nodes. + typedef typename TR::DistMap DistMap; + ///The type of the map that indicates which nodes are reached. typedef typename TR::ReachedMap ReachedMap; - ///The type of the map indicating which nodes are processed. + ///The type of the map that indicates which nodes are processed. typedef typename TR::ProcessedMap ProcessedMap; - ///The type of the map that stores the dists of the nodes. - typedef typename TR::DistMap DistMap; + ///The type of the paths. + typedef PredMapPath Path; + + ///The traits class. + typedef TR Traits; + private: typedef typename Digraph::Node Node; @@ -166,23 +172,23 @@ typedef typename Digraph::Arc Arc; typedef typename Digraph::OutArcIt OutArcIt; - /// Pointer to the underlying digraph. + //Pointer to the underlying digraph. const Digraph *G; - ///Pointer to the map of predecessors arcs. + //Pointer to the map of predecessor arcs. PredMap *_pred; - ///Indicates if \ref _pred is locally allocated (\c true) or not. + //Indicates if _pred is locally allocated (true) or not. bool local_pred; - ///Pointer to the map of distances. + //Pointer to the map of distances. DistMap *_dist; - ///Indicates if \ref _dist is locally allocated (\c true) or not. + //Indicates if _dist is locally allocated (true) or not. bool local_dist; - ///Pointer to the map of reached status of the nodes. + //Pointer to the map of reached status of the nodes. ReachedMap *_reached; - ///Indicates if \ref _reached is locally allocated (\c true) or not. + //Indicates if _reached is locally allocated (true) or not. bool local_reached; - ///Pointer to the map of processed status of the nodes. + //Pointer to the map of processed status of the nodes. ProcessedMap *_processed; - ///Indicates if \ref _processed is locally allocated (\c true) or not. + //Indicates if _processed is locally allocated (true) or not. bool local_processed; std::vector _queue; @@ -190,7 +196,6 @@ int _curr_dist; ///Creates the maps if necessary. - ///\todo Better memory allocation (instead of new). void create_maps() { @@ -233,10 +238,10 @@ } }; ///\brief \ref named-templ-param "Named parameter" for setting - ///PredMap type + ///\ref PredMap type. /// - ///\ref named-templ-param "Named parameter" for setting PredMap type - /// + ///\ref named-templ-param "Named parameter" for setting + ///\ref PredMap type. template struct DefPredMap : public Bfs< Digraph, DefPredMapTraits > { typedef Bfs< Digraph, DefPredMapTraits > Create; @@ -251,10 +256,10 @@ } }; ///\brief \ref named-templ-param "Named parameter" for setting - ///DistMap type + ///\ref DistMap type. /// - ///\ref named-templ-param "Named parameter" for setting DistMap type - /// + ///\ref named-templ-param "Named parameter" for setting + ///\ref DistMap type. template struct DefDistMap : public Bfs< Digraph, DefDistMapTraits > { typedef Bfs< Digraph, DefDistMapTraits > Create; @@ -269,10 +274,10 @@ } }; ///\brief \ref named-templ-param "Named parameter" for setting - ///ReachedMap type + ///\ref ReachedMap type. /// - ///\ref named-templ-param "Named parameter" for setting ReachedMap type - /// + ///\ref named-templ-param "Named parameter" for setting + ///\ref ReachedMap type. template struct DefReachedMap : public Bfs< Digraph, DefReachedMapTraits > { typedef Bfs< Digraph, DefReachedMapTraits > Create; @@ -287,10 +292,10 @@ } }; ///\brief \ref named-templ-param "Named parameter" for setting - ///ProcessedMap type + ///\ref ProcessedMap type. /// - ///\ref named-templ-param "Named parameter" for setting ProcessedMap type - /// + ///\ref named-templ-param "Named parameter" for setting + ///\ref ProcessedMap type. template struct DefProcessedMap : public Bfs< Digraph, DefProcessedMapTraits > { typedef Bfs< Digraph, DefProcessedMapTraits > Create; @@ -298,16 +303,16 @@ struct DefDigraphProcessedMapTraits : public Traits { typedef typename Digraph::template NodeMap ProcessedMap; - static ProcessedMap *createProcessedMap(const Digraph &G) + static ProcessedMap *createProcessedMap(const Digraph &g) { - return new ProcessedMap(G); + return new ProcessedMap(g); } }; - ///\brief \ref named-templ-param "Named parameter" - ///for setting the ProcessedMap type to be Digraph::NodeMap. + ///\brief \ref named-templ-param "Named parameter" for setting + ///\ref ProcessedMap type to be Digraph::NodeMap. /// - ///\ref named-templ-param "Named parameter" - ///for setting the ProcessedMap type to be Digraph::NodeMap. + ///\ref named-templ-param "Named parameter" for setting + ///\ref ProcessedMap type to be Digraph::NodeMap. ///If you don't set it explicitly, it will be automatically allocated. template struct DefProcessedMapToBeDefaultMap : @@ -321,10 +326,10 @@ ///Constructor. - ///\param _G the digraph the algorithm will run on. - /// - Bfs(const Digraph& _G) : - G(&_G), + ///Constructor. + ///\param g The digraph the algorithm runs on. + Bfs(const Digraph &g) : + G(&g), _pred(NULL), local_pred(false), _dist(NULL), local_dist(false), _reached(NULL), local_reached(false), @@ -340,9 +345,9 @@ if(local_processed) delete _processed; } - ///Sets the map storing the predecessor arcs. + ///Sets the map that stores the predecessor arcs. - ///Sets the map storing the predecessor arcs. + ///Sets the map that stores the predecessor arcs. ///If you don't use this function before calling \ref run(), ///it will allocate one. The destructor deallocates this ///automatically allocated map, of course. @@ -357,9 +362,9 @@ return *this; } - ///Sets the map indicating the reached nodes. + ///Sets the map that indicates which nodes are reached. - ///Sets the map indicating the reached nodes. + ///Sets the map that indicates which nodes are reached. ///If you don't use this function before calling \ref run(), ///it will allocate one. The destructor deallocates this ///automatically allocated map, of course. @@ -374,9 +379,9 @@ return *this; } - ///Sets the map indicating the processed nodes. + ///Sets the map that indicates which nodes are processed. - ///Sets the map indicating the processed nodes. + ///Sets the map that indicates which nodes are processed. ///If you don't use this function before calling \ref run(), ///it will allocate one. The destructor deallocates this ///automatically allocated map, of course. @@ -391,9 +396,10 @@ return *this; } - ///Sets the map storing the distances calculated by the algorithm. + ///Sets the map that stores the distances of the nodes. - ///Sets the map storing the distances calculated by the algorithm. + ///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(), ///it will allocate one. The destructor deallocates this ///automatically allocated map, of course. @@ -409,20 +415,21 @@ } public: + ///\name Execution control ///The simplest way to execute the algorithm is to use - ///one of the member functions called \c run(...). + ///one of the member functions called \ref lemon::Bfs::run() "run()". ///\n - ///If you need more control on the execution, - ///first you must call \ref init(), then you can add several source nodes - ///with \ref addSource(). - ///Finally \ref start() will perform the actual path - ///computation. + ///If you need more control on the execution, first you must call + ///\ref lemon::Bfs::init() "init()", then you can add several source + ///nodes with \ref lemon::Bfs::addSource() "addSource()". + ///Finally \ref lemon::Bfs::start() "start()" will perform the + ///actual path computation. ///@{ - ///\brief Initializes the internal data structures. - /// + ///Initializes the internal data structures. + ///Initializes the internal data structures. /// void init() @@ -460,7 +467,7 @@ /// ///\return The processed node. /// - ///\warning The queue must not be empty! + ///\pre The queue must not be empty. Node processNextNode() { if(_queue_tail==_queue_next_dist) { @@ -482,16 +489,17 @@ ///Processes the next node. - ///Processes the next node. And checks that the given target node + ///Processes the next node and checks if the given target node ///is reached. If the target node is reachable from the processed - ///node then the reached parameter will be set true. The reached - ///parameter should be initially false. + ///node, then the \c reach parameter will be set to \c true. /// ///\param target The target node. - ///\retval reach Indicates that the target node is reached. + ///\retval reach Indicates if the target node is reached. + ///It should be initially \c false. + /// ///\return The processed node. /// - ///\warning The queue must not be empty! + ///\pre The queue must not be empty. Node processNextNode(Node target, bool& reach) { if(_queue_tail==_queue_next_dist) { @@ -514,16 +522,19 @@ ///Processes the next node. - ///Processes the next node. And checks that at least one of - ///reached node has true value in the \c nm node map. If one node - ///with true value is reachable from the processed node then the - ///rnode parameter will be set to the first of such nodes. + ///Processes the next node and checks if at least one of reached + ///nodes has \c true value in the \c nm node map. If one node + ///with \c true value is reachable from the processed node, then the + ///\c rnode parameter will be set to the first of such nodes. /// - ///\param nm The node map of possible targets. + ///\param nm A \c bool (or convertible) node map that indicates the + ///possible targets. ///\retval rnode The reached target node. + ///It should be initially \c INVALID. + /// ///\return The processed node. /// - ///\warning The queue must not be empty! + ///\pre The queue must not be empty. template Node processNextNode(const NM& nm, Node& rnode) { @@ -545,58 +556,73 @@ return n; } - ///Next node to be processed. + ///The next node to be processed. - ///Next node to be processed. - /// - ///\return The next node to be processed or INVALID if the queue is - /// empty. - Node nextNode() + ///Returns the next node to be processed or \c INVALID if the queue + ///is empty. + Node nextNode() const { return _queue_tail<_queue_head?_queue[_queue_tail]:INVALID; } ///\brief Returns \c false if there are nodes - ///to be processed in the queue + ///to be processed. /// ///Returns \c false if there are nodes - ///to be processed in the queue - bool emptyQueue() { return _queue_tail==_queue_head; } + ///to be processed in the queue. + bool emptyQueue() const { return _queue_tail==_queue_head; } + ///Returns the number of the nodes to be processed. ///Returns the number of the nodes to be processed in the queue. - int queueSize() { return _queue_head-_queue_tail; } + int queueSize() const { return _queue_head-_queue_tail; } ///Executes the algorithm. ///Executes the algorithm. /// - ///\pre init() must be called and at least one node should be added - ///with addSource() before using this function. + ///This method runs the %BFS algorithm from the root node(s) + ///in order to compute the shortest path to each node. /// - ///This method runs the %BFS algorithm from the root node(s) - ///in order to - ///compute the - ///shortest path to each node. The algorithm computes - ///- The shortest path tree. - ///- The distance of each node from the root(s). + ///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. + /// + ///\note b.start() is just a shortcut of the following code. + ///\code + /// while ( !b.emptyQueue() ) { + /// b.processNextNode(); + /// } + ///\endcode void start() { while ( !emptyQueue() ) processNextNode(); } - ///Executes the algorithm until \c dest is reached. + ///Executes the algorithm until the given target node is reached. - ///Executes the algorithm until \c dest is reached. - /// - ///\pre init() must be called and at least one node should be added - ///with addSource() before using this function. + ///Executes the algorithm until the given target node is reached. /// ///This method runs the %BFS algorithm from the root node(s) ///in order to compute the shortest path to \c dest. + /// ///The algorithm computes - ///- The shortest path to \c dest. - ///- The distance of \c dest from the root(s). + ///- the shortest path to \c dest, + ///- the distance of \c dest from the root(s). + /// + ///\pre init() must be called and at least one root node should be + ///added with addSource() before using this function. + /// + ///\note b.start(t) is just a shortcut of the following code. + ///\code + /// bool reach = false; + /// while ( !b.emptyQueue() && !reach ) { + /// b.processNextNode(t, reach); + /// } + ///\endcode void start(Node dest) { bool reach = false; @@ -607,17 +633,29 @@ ///Executes the algorithm until a condition is met. /// - ///\pre init() must be called and at least one node should be added - ///with addSource() before using this function. + ///This method runs the %BFS algorithm from the root node(s) in + ///order to compute the shortest path to a node \c v with + /// nm[v] true, if such a node can be found. /// - ///\param nm must be a bool (or convertible) node map. The - ///algorithm will stop when it reaches a node \c v with - /// nm[v] true. + ///\param nm A \c bool (or convertible) node map. The algorithm + ///will stop when it reaches a node \c v with nm[v] true. /// ///\return The reached node \c v with nm[v] true or ///\c INVALID if no such node was found. - template - Node start(const NM &nm) + /// + ///\pre init() must be called and at least one root node should be + ///added with addSource() before using this function. + /// + ///\note b.start(nm) is just a shortcut of the following code. + ///\code + /// Node rnode = INVALID; + /// while ( !b.emptyQueue() && rnode == INVALID ) { + /// b.processNextNode(nm, rnode); + /// } + /// return rnode; + ///\endcode + template + Node start(const NodeBoolMap &nm) { Node rnode = INVALID; while ( !emptyQueue() && rnode == INVALID ) { @@ -626,16 +664,16 @@ return rnode; } - ///Runs %BFS algorithm from node \c s. + ///Runs the algorithm from the given node. - ///This method runs the %BFS algorithm from a root node \c s - ///in order to - ///compute the - ///shortest path to each node. The algorithm computes - ///- The shortest path tree. - ///- The distance of each node from the root. + ///This method runs the %BFS algorithm from node \c s + ///in order to compute the shortest path to each node. /// - ///\note b.run(s) is just a shortcut of the following code. + ///The algorithm computes + ///- the shortest path tree, + ///- the distance of each node from the root. + /// + ///\note b.run(s) is just a shortcut of the following code. ///\code /// b.init(); /// b.addSource(s); @@ -649,12 +687,14 @@ ///Finds the shortest path between \c s and \c t. - ///Finds the shortest path between \c s and \c t. + ///This method runs the %BFS algorithm from node \c s + ///in order to compute the shortest path to \c t. /// - ///\return The length of the shortest s---t path if there exists one, - ///0 otherwise. - ///\note Apart from the return value, b.run(s) is - ///just a shortcut of the following code. + ///\return The length of the shortest s--t path, + ///if \c t is reachable form \c s, \c 0 otherwise. + /// + ///\note Apart from the return value, b.run(s,t) is just a + ///shortcut of the following code. ///\code /// b.init(); /// b.addSource(s); @@ -667,116 +707,152 @@ return reached(t) ? _curr_dist : 0; } + ///Runs the algorithm to visit all nodes in the digraph. + + ///This method runs the %BFS algorithm 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 b.run(s) is just a shortcut of the following code. + ///\code + /// b.init(); + /// for (NodeIt n(gr); n != INVALID; ++n) { + /// if (!b.reached(n)) { + /// b.addSource(n); + /// b.start(); + /// } + /// } + ///\endcode + void run() { + init(); + for (NodeIt n(*G); n != INVALID; ++n) { + if (!reached(n)) { + addSource(n); + start(); + } + } + } + ///@} ///\name Query Functions ///The result of the %BFS algorithm can be obtained using these ///functions.\n - ///Before the use of these functions, - ///either run() or start() must be calleb. + ///Either \ref lemon::Bfs::run() "run()" or \ref lemon::Bfs::start() + ///"start()" must be called before using them. ///@{ - typedef PredMapPath Path; + ///The shortest path to a node. - ///Gives back the shortest path. - - ///Gives back the shortest path. - ///\pre The \c t should be reachable from the source. - Path path(Node t) - { - return Path(*G, *_pred, t); - } + ///Returns the shortest path to a node. + /// + ///\warning \c t should be reachable from the root(s). + /// + ///\pre Either \ref run() or \ref start() must be called before + ///using this function. + Path path(Node t) const { return Path(*G, *_pred, t); } ///The distance of a node from the root(s). ///Returns the distance of a node from the root(s). - ///\pre \ref run() must be called before using this function. - ///\warning If node \c v in unreachable from the root(s) the return value - ///of this function is undefined. + /// + ///\warning If node \c v is not reachable from the root(s), then + ///the return value of this function is undefined. + /// + ///\pre Either \ref run() or \ref start() must be called before + ///using this function. int dist(Node v) const { return (*_dist)[v]; } - ///Returns the 'previous arc' of the shortest path tree. + ///Returns the 'previous arc' of the shortest path tree for a node. - ///For a node \c v it returns the 'previous arc' - ///of the shortest path tree, - ///i.e. it returns the last arc of a shortest path from the root(s) to \c - ///v. It is \ref INVALID - ///if \c v is unreachable from the root(s) or \c v is a root. The - ///shortest path tree used here is equal to the shortest path tree used in - ///\ref predNode(). - ///\pre Either \ref run() or \ref start() must be called before using - ///this function. + ///This function returns the 'previous arc' of the shortest path + ///tree for the node \c v, i.e. it returns the last arc of a + ///shortest path from the root(s) to \c v. It is \c INVALID if \c v + ///is not reachable 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(). + /// + ///\pre Either \ref run() or \ref start() must be called before + ///using this function. Arc predArc(Node v) const { return (*_pred)[v];} - ///Returns the 'previous node' of the shortest path tree. + ///Returns the 'previous node' of the shortest path tree for a node. - ///For a node \c v it returns the 'previous node' - ///of the shortest path tree, - ///i.e. it returns the last but one node from a shortest path from the - ///root(a) to \c /v. - ///It is INVALID if \c v is unreachable from the root(s) or - ///if \c v itself a root. + ///This function returns the 'previous node' of the shortest path + ///tree for the node \c v, i.e. it returns the last but one node + ///from a shortest path from the root(s) to \c v. It is \c INVALID + ///if \c v is not reachable 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(). + /// ///\pre Either \ref run() or \ref start() must be called before ///using this function. Node predNode(Node v) const { return (*_pred)[v]==INVALID ? INVALID: G->source((*_pred)[v]); } - ///Returns a reference to the NodeMap of distances. - - ///Returns a reference to the NodeMap of distances. - ///\pre Either \ref run() or \ref init() must - ///be called before using this function. + ///\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;} - ///Returns a reference to the shortest path tree map. - - ///Returns a reference to the NodeMap of the arcs of the - ///shortest path tree. + ///\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. + /// ///\pre Either \ref run() or \ref init() ///must be called before using this function. const PredMap &predMap() const { return *_pred;} - ///Checks if a node is reachable from the root. + ///Checks if a node is reachable from the root(s). - ///Returns \c true if \c v is reachable from the root. - ///\warning The source nodes are indicated as unreached. + ///Returns \c true if \c v is reachable from the root(s). ///\pre Either \ref run() or \ref start() ///must be called before using this function. - /// - bool reached(Node v) { return (*_reached)[v]; } + bool reached(Node v) const { return (*_reached)[v]; } ///@} }; - ///Default traits class of Bfs function. + ///Default traits class of bfs() function. - ///Default traits class of Bfs function. + ///Default traits class of bfs() function. ///\tparam GR Digraph type. template struct BfsWizardDefaultTraits { - ///The digraph type the algorithm runs on. + ///The type of the digraph the algorithm runs on. typedef GR Digraph; - ///\brief The type of the map that stores the last + + ///\brief The type of the map that stores the predecessor ///arcs of the shortest paths. /// - ///The type of the map that stores the last + ///The type of the map that stores the predecessor ///arcs of the shortest paths. ///It must meet the \ref concepts::WriteMap "WriteMap" concept. - /// - typedef NullMap PredMap; - ///Instantiates a PredMap. + typedef NullMap PredMap; + ///Instantiates a \ref PredMap. ///This function instantiates a \ref PredMap. - ///\param g is the digraph, to which we would like to define the PredMap. + ///\param g is the digraph, to which we would like to define the + ///\ref PredMap. ///\todo The digraph alone may be insufficient to initialize #ifdef DOXYGEN - static PredMap *createPredMap(const GR &g) + static PredMap *createPredMap(const Digraph &g) #else - static PredMap *createPredMap(const GR &) + static PredMap *createPredMap(const Digraph &) #endif { return new PredMap(); @@ -786,63 +862,63 @@ ///The type of the map that indicates which nodes are processed. ///It must meet the \ref concepts::WriteMap "WriteMap" concept. - ///\todo named parameter to set this type, function to read and write. typedef NullMap ProcessedMap; - ///Instantiates a ProcessedMap. + ///Instantiates a \ref ProcessedMap. ///This function instantiates a \ref ProcessedMap. ///\param g is the digraph, to which - ///we would like to define the \ref ProcessedMap + ///we would like to define the \ref ProcessedMap. #ifdef DOXYGEN - static ProcessedMap *createProcessedMap(const GR &g) + static ProcessedMap *createProcessedMap(const Digraph &g) #else - static ProcessedMap *createProcessedMap(const GR &) + static ProcessedMap *createProcessedMap(const Digraph &) #endif { return new ProcessedMap(); } + ///The type of the map that indicates which nodes are reached. ///The type of the map that indicates which nodes are reached. - ///It must meet the \ref concepts::WriteMap "WriteMap" concept. - ///\todo named parameter to set this type, function to read and write. + ///It must meet the \ref concepts::ReadWriteMap "ReadWriteMap" concept. typedef typename Digraph::template NodeMap ReachedMap; - ///Instantiates a ReachedMap. + ///Instantiates a \ref ReachedMap. ///This function instantiates a \ref ReachedMap. - ///\param G is the digraph, to which + ///\param g is the digraph, to which ///we would like to define the \ref ReachedMap. - static ReachedMap *createReachedMap(const GR &G) + static ReachedMap *createReachedMap(const Digraph &g) { - return new ReachedMap(G); + return new ReachedMap(g); } - ///The type of the map that stores the dists of the nodes. - ///The type of the map that stores the dists of the nodes. + ///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 meet the \ref concepts::WriteMap "WriteMap" concept. /// typedef NullMap DistMap; - ///Instantiates a DistMap. + ///Instantiates a \ref DistMap. ///This function instantiates a \ref DistMap. ///\param g is the digraph, to which we would like to define ///the \ref DistMap #ifdef DOXYGEN - static DistMap *createDistMap(const GR &g) + static DistMap *createDistMap(const Digraph &g) #else - static DistMap *createDistMap(const GR &) + static DistMap *createDistMap(const Digraph &) #endif { return new DistMap(); } }; - /// Default traits used by \ref BfsWizard + /// Default traits class used by \ref BfsWizard /// To make it easier to use Bfs algorithm - ///we have created a wizard class. + /// we have created a wizard class. /// This \ref BfsWizard class needs default traits, - ///as well as the \ref Bfs class. + /// as well as the \ref Bfs class. /// The \ref BfsWizardBase is a class to be the default traits of the /// \ref BfsWizard class. template @@ -851,20 +927,20 @@ typedef BfsWizardDefaultTraits Base; protected: - /// Type of the nodes in the digraph. + //The type of the nodes in the digraph. typedef typename Base::Digraph::Node Node; - /// Pointer to the underlying digraph. + //Pointer to the digraph the algorithm runs on. void *_g; - ///Pointer to the map of reached nodes. + //Pointer to the map of reached nodes. void *_reached; - ///Pointer to the map of processed nodes. + //Pointer to the map of processed nodes. void *_processed; - ///Pointer to the map of predecessors arcs. + //Pointer to the map of predecessors arcs. void *_pred; - ///Pointer to the map of distances. + //Pointer to the map of distances. void *_dist; - ///Pointer to the source node. + //Pointer to the source node. Node _source; public: @@ -873,26 +949,28 @@ /// This constructor does not require parameters, therefore it initiates /// all of the attributes to default values (0, INVALID). BfsWizardBase() : _g(0), _reached(0), _processed(0), _pred(0), - _dist(0), _source(INVALID) {} + _dist(0), _source(INVALID) {} /// Constructor. /// This constructor requires some parameters, /// listed in the parameters list. /// Others are initiated to 0. - /// \param g is the initial value of \ref _g - /// \param s is the initial value of \ref _source + /// \param g The digraph the algorithm runs on. + /// \param s The source node. BfsWizardBase(const GR &g, Node s=INVALID) : _g(reinterpret_cast(const_cast(&g))), _reached(0), _processed(0), _pred(0), _dist(0), _source(s) {} }; - /// A class to make the usage of Bfs algorithm easier + /// Auxiliary class for the function type interface of BFS algorithm. - /// This class is created to make it easier to use Bfs algorithm. - /// It uses the functions and features of the plain \ref Bfs, - /// but it is much simpler to use it. + /// This auxiliary class is created to implement the function type + /// interface of \ref Bfs algorithm. It uses the functions and features + /// of the plain \ref Bfs, but it is much simpler to use it. + /// It should only be used through the \ref bfs() function, which makes + /// it easier to use the algorithm. /// /// Simplicity means that the way to change the types defined /// in the traits class is based on functions that returns the new class @@ -901,41 +979,37 @@ /// the new class with the modified type comes from /// the original class by using the :: /// operator. In the case of \ref BfsWizard only - /// a function have to be called and it will + /// a function have to be called, and it will /// return the needed class. /// - /// It does not have own \ref run method. When its \ref run method is called - /// it initiates a plain \ref Bfs class, and calls the \ref Bfs::run - /// method of it. + /// It does not have own \ref run() method. When its \ref run() method + /// is called, it initiates a plain \ref Bfs object, and calls the + /// \ref Bfs::run() method of it. template class BfsWizard : public TR { typedef TR Base; - ///The type of the underlying digraph. + ///The type of the digraph the algorithm runs on. typedef typename TR::Digraph Digraph; - //\e + typedef typename Digraph::Node Node; - //\e typedef typename Digraph::NodeIt NodeIt; - //\e typedef typename Digraph::Arc Arc; - //\e typedef typename Digraph::OutArcIt OutArcIt; - ///\brief The type of the map that stores - ///the reached nodes - typedef typename TR::ReachedMap ReachedMap; - ///\brief The type of the map that stores - ///the processed nodes - typedef typename TR::ProcessedMap ProcessedMap; - ///\brief The type of the map that stores the last + ///\brief The type of the map that stores the predecessor ///arcs of the shortest paths. typedef typename TR::PredMap PredMap; - ///The type of the map that stores the dists of the nodes. + ///\brief The type of the map that stores the distances of the nodes. typedef typename TR::DistMap DistMap; + ///\brief The type of the map that indicates which nodes are reached. + typedef typename TR::ReachedMap ReachedMap; + ///\brief The type of the map that indicates which nodes are processed. + typedef typename TR::ProcessedMap ProcessedMap; public: + /// Constructor. BfsWizard() : TR() {} @@ -951,10 +1025,10 @@ ~BfsWizard() {} - ///Runs Bfs algorithm from a given node. + ///Runs BFS algorithm from a source node. - ///Runs Bfs algorithm from a given node. - ///The node can be given by the \ref source function. + ///Runs BFS algorithm from a source node. + ///The node can be given with the \ref source() function. void run() { if(Base::_source==INVALID) throw UninitializedParameter(); @@ -970,9 +1044,9 @@ alg.run(Base::_source); } - ///Runs Bfs algorithm from the given node. + ///Runs BFS algorithm from the given node. - ///Runs Bfs algorithm from the given node. + ///Runs BFS algorithm from the given node. ///\param s is the given source. void run(Node s) { @@ -980,89 +1054,6 @@ run(); } - template - struct DefPredMapBase : public Base { - typedef T PredMap; - static PredMap *createPredMap(const Digraph &) { return 0; }; - DefPredMapBase(const TR &b) : TR(b) {} - }; - - ///\brief \ref named-templ-param "Named parameter" - ///function for setting PredMap - /// - /// \ref named-templ-param "Named parameter" - ///function for setting PredMap - /// - template - BfsWizard > predMap(const T &t) - { - Base::_pred=reinterpret_cast(const_cast(&t)); - return BfsWizard >(*this); - } - - - template - struct DefReachedMapBase : public Base { - typedef T ReachedMap; - static ReachedMap *createReachedMap(const Digraph &) { return 0; }; - DefReachedMapBase(const TR &b) : TR(b) {} - }; - - ///\brief \ref named-templ-param "Named parameter" - ///function for setting ReachedMap - /// - /// \ref named-templ-param "Named parameter" - ///function for setting ReachedMap - /// - template - BfsWizard > reachedMap(const T &t) - { - Base::_reached=reinterpret_cast(const_cast(&t)); - return BfsWizard >(*this); - } - - - template - struct DefProcessedMapBase : public Base { - typedef T ProcessedMap; - static ProcessedMap *createProcessedMap(const Digraph &) { return 0; }; - DefProcessedMapBase(const TR &b) : TR(b) {} - }; - - ///\brief \ref named-templ-param "Named parameter" - ///function for setting ProcessedMap - /// - /// \ref named-templ-param "Named parameter" - ///function for setting ProcessedMap - /// - template - BfsWizard > processedMap(const T &t) - { - Base::_processed=reinterpret_cast(const_cast(&t)); - return BfsWizard >(*this); - } - - - template - struct DefDistMapBase : public Base { - typedef T DistMap; - static DistMap *createDistMap(const Digraph &) { return 0; }; - DefDistMapBase(const TR &b) : TR(b) {} - }; - - ///\brief \ref named-templ-param "Named parameter" - ///function for setting DistMap type - /// - /// \ref named-templ-param "Named parameter" - ///function for setting DistMap type - /// - template - BfsWizard > distMap(const T &t) - { - Base::_dist=reinterpret_cast(const_cast(&t)); - return BfsWizard >(*this); - } - /// Sets the source node, from which the Bfs algorithm runs. /// Sets the source node, from which the Bfs algorithm runs. @@ -1073,6 +1064,78 @@ return *this; } + template + struct DefPredMapBase : public Base { + typedef T PredMap; + static PredMap *createPredMap(const Digraph &) { return 0; }; + DefPredMapBase(const TR &b) : TR(b) {} + }; + ///\brief \ref named-templ-param "Named parameter" + ///for setting \ref PredMap object. + /// + /// \ref named-templ-param "Named parameter" + ///for setting \ref PredMap object. + template + BfsWizard > predMap(const T &t) + { + Base::_pred=reinterpret_cast(const_cast(&t)); + return BfsWizard >(*this); + } + + template + struct DefReachedMapBase : public Base { + typedef T ReachedMap; + static ReachedMap *createReachedMap(const Digraph &) { return 0; }; + DefReachedMapBase(const TR &b) : TR(b) {} + }; + ///\brief \ref named-templ-param "Named parameter" + ///for setting \ref ReachedMap object. + /// + /// \ref named-templ-param "Named parameter" + ///for setting \ref ReachedMap object. + template + BfsWizard > reachedMap(const T &t) + { + Base::_reached=reinterpret_cast(const_cast(&t)); + return BfsWizard >(*this); + } + + template + struct DefProcessedMapBase : public Base { + typedef T ProcessedMap; + static ProcessedMap *createProcessedMap(const Digraph &) { return 0; }; + DefProcessedMapBase(const TR &b) : TR(b) {} + }; + ///\brief \ref named-templ-param "Named parameter" + ///for setting \ref ProcessedMap object. + /// + /// \ref named-templ-param "Named parameter" + ///for setting \ref ProcessedMap object. + template + BfsWizard > processedMap(const T &t) + { + Base::_processed=reinterpret_cast(const_cast(&t)); + return BfsWizard >(*this); + } + + template + struct DefDistMapBase : public Base { + typedef T DistMap; + static DistMap *createDistMap(const Digraph &) { return 0; }; + DefDistMapBase(const TR &b) : TR(b) {} + }; + ///\brief \ref named-templ-param "Named parameter" + ///for setting \ref DistMap object. + /// + /// \ref named-templ-param "Named parameter" + ///for setting \ref DistMap object. + template + BfsWizard > distMap(const T &t) + { + Base::_dist=reinterpret_cast(const_cast(&t)); + return BfsWizard >(*this); + } + }; ///Function type interface for Bfs algorithm. @@ -1100,38 +1163,38 @@ } #ifdef DOXYGEN - /// \brief Visitor class for bfs. + /// \brief Visitor class for BFS. /// /// This class defines the interface of the BfsVisit events, and - /// it could be the base of a real Visitor class. + /// it could be the base of a real visitor class. template struct BfsVisitor { typedef _Digraph Digraph; typedef typename Digraph::Arc Arc; typedef typename Digraph::Node Node; - /// \brief Called when the arc reach a node. + /// \brief Called for the source node(s) of the BFS. /// - /// It is called when the bfs find an arc which target is not - /// reached yet. + /// This function is called for the source node(s) of the BFS. + void start(const Node& node) {} + /// \brief Called when a node is reached first time. + /// + /// This function is called when a node is reached first time. + void reach(const Node& node) {} + /// \brief Called when a node is processed. + /// + /// This function is called when a node is processed. + void process(const Node& node) {} + /// \brief Called when an arc reaches a new node. + /// + /// This function is called when the BFS finds an arc whose target node + /// is not reached yet. void discover(const Arc& arc) {} - /// \brief Called when the node reached first time. - /// - /// It is Called when the node reached first time. - void reach(const Node& node) {} - /// \brief Called when the arc examined but target of the arc + /// \brief Called when an arc is examined but its target node is /// already discovered. /// - /// It called when the arc examined but the target of the arc + /// This function is called when an arc is examined but its target node is /// already discovered. void examine(const Arc& arc) {} - /// \brief Called for the source node of the bfs. - /// - /// It is called for the source node of the bfs. - void start(const Node& node) {} - /// \brief Called when the node processed. - /// - /// It is Called when the node processed. - void process(const Node& node) {} }; #else template @@ -1139,22 +1202,22 @@ typedef _Digraph Digraph; typedef typename Digraph::Arc Arc; typedef typename Digraph::Node Node; + void start(const Node&) {} + void reach(const Node&) {} + void process(const Node&) {} void discover(const Arc&) {} - void reach(const Node&) {} void examine(const Arc&) {} - void start(const Node&) {} - void process(const Node&) {} template struct Constraints { void constraints() { Arc arc; Node node; + visitor.start(node); + visitor.reach(node); + visitor.process(node); visitor.discover(arc); - visitor.reach(node); visitor.examine(arc); - visitor.start(node); - visitor.process(node); } _Visitor& visitor; }; @@ -1164,21 +1227,20 @@ /// \brief Default traits class of BfsVisit class. /// /// Default traits class of BfsVisit class. - /// \tparam _Digraph Digraph type. + /// \tparam _Digraph The type of the digraph the algorithm runs on. template struct BfsVisitDefaultTraits { - /// \brief The digraph type the algorithm runs on. + /// \brief The type of the digraph the algorithm runs on. typedef _Digraph Digraph; /// \brief The type of the map that indicates which nodes are reached. /// /// The type of the map that indicates which nodes are reached. - /// It must meet the \ref concepts::WriteMap "WriteMap" concept. - /// \todo named parameter to set this type, function to read and write. + /// It must meet the \ref concepts::ReadWriteMap "ReadWriteMap" concept. typedef typename Digraph::template NodeMap ReachedMap; - /// \brief Instantiates a ReachedMap. + /// \brief Instantiates a \ref ReachedMap. /// /// This function instantiates a \ref ReachedMap. /// \param digraph is the digraph, to which @@ -1191,28 +1253,28 @@ /// \ingroup search /// - /// \brief %BFS Visit algorithm class. + /// \brief %BFS algorithm class with visitor interface. /// /// This class provides an efficient implementation of the %BFS algorithm /// with visitor interface. /// /// The %BfsVisit class provides an alternative interface to the Bfs /// class. It works with callback mechanism, the BfsVisit object calls - /// on every bfs event the \c Visitor class member functions. + /// the member functions of the \c Visitor class on every BFS event. /// - /// \tparam _Digraph The digraph type the algorithm runs on. + /// \tparam _Digraph The type of the digraph the algorithm runs on. /// The default value is - /// \ref ListDigraph. The value of _Digraph is not used directly by Bfs, it - /// is only passed to \ref BfsDefaultTraits. - /// \tparam _Visitor The Visitor object for the algorithm. The - /// \ref BfsVisitor "BfsVisitor<_Digraph>" is an empty Visitor which - /// does not observe the Bfs events. If you want to observe the bfs - /// events you should implement your own Visitor class. + /// \ref ListDigraph. The value of _Digraph is not used directly by + /// \ref BfsVisit, it is only passed to \ref BfsVisitDefaultTraits. + /// \tparam _Visitor The Visitor type that is used by the algorithm. + /// \ref BfsVisitor "BfsVisitor<_Digraph>" is an empty visitor, which + /// does not observe the BFS events. If you want to observe the BFS + /// events, you should implement your own visitor class. /// \tparam _Traits Traits class to set various data types used by the /// algorithm. The default traits class is /// \ref BfsVisitDefaultTraits "BfsVisitDefaultTraits<_Digraph>". /// See \ref BfsVisitDefaultTraits for the documentation of - /// a Bfs visit traits class. + /// a BFS visit traits class. #ifdef DOXYGEN template #else @@ -1226,7 +1288,7 @@ /// \brief \ref Exception for uninitialized parameters. /// /// This error represents problems in the initialization - /// of the parameters of the algorithms. + /// of the parameters of the algorithm. class UninitializedParameter : public lemon::UninitializedParameter { public: virtual const char* what() const throw() @@ -1235,13 +1297,16 @@ } }; + ///The traits class. typedef _Traits Traits; + ///The type of the digraph the algorithm runs on. typedef typename Traits::Digraph Digraph; + ///The visitor type used by the algorithm. typedef _Visitor Visitor; - ///The type of the map indicating which nodes are reached. + ///The type of the map that indicates which nodes are reached. typedef typename Traits::ReachedMap ReachedMap; private: @@ -1251,21 +1316,20 @@ typedef typename Digraph::Arc Arc; typedef typename Digraph::OutArcIt OutArcIt; - /// Pointer to the underlying digraph. + //Pointer to the underlying digraph. const Digraph *_digraph; - /// Pointer to the visitor object. + //Pointer to the visitor object. Visitor *_visitor; - ///Pointer to the map of reached status of the nodes. + //Pointer to the map of reached status of the nodes. ReachedMap *_reached; - ///Indicates if \ref _reached is locally allocated (\c true) or not. + //Indicates if _reached is locally allocated (true) or not. bool local_reached; std::vector _list; int _list_front, _list_back; - /// \brief Creates the maps if necessary. - /// - /// Creates the maps if necessary. + ///Creates the maps if necessary. + ///\todo Better memory allocation (instead of new). void create_maps() { if(!_reached) { local_reached = true; @@ -1292,9 +1356,9 @@ } }; /// \brief \ref named-templ-param "Named parameter" for setting - /// ReachedMap type + /// ReachedMap type. /// - /// \ref named-templ-param "Named parameter" for setting ReachedMap type + /// \ref named-templ-param "Named parameter" for setting ReachedMap type. template struct DefReachedMap : public BfsVisit< Digraph, Visitor, DefReachedMapTraits > { @@ -1308,25 +1372,22 @@ /// /// Constructor. /// - /// \param digraph the digraph the algorithm will run on. - /// \param visitor The visitor of the algorithm. - /// + /// \param digraph The digraph the algorithm runs on. + /// \param visitor The visitor object of the algorithm. BfsVisit(const Digraph& digraph, Visitor& visitor) : _digraph(&digraph), _visitor(&visitor), _reached(0), local_reached(false) {} /// \brief Destructor. - /// - /// Destructor. ~BfsVisit() { if(local_reached) delete _reached; } - /// \brief Sets the map indicating if a node is reached. + /// \brief Sets the map that indicates which nodes are reached. /// - /// Sets the map indicating if a node is reached. + /// Sets the map that indicates which nodes are reached. /// If you don't use this function before calling \ref run(), - /// it will allocate one. The destuctor deallocates this + /// it will allocate one. The destructor deallocates this /// automatically allocated map, of course. /// \return (*this) BfsVisit &reachedMap(ReachedMap &m) { @@ -1339,21 +1400,23 @@ } public: + /// \name Execution control /// The simplest way to execute the algorithm is to use - /// one of the member functions called \c run(...). + /// one of the member functions called \ref lemon::BfsVisit::run() + /// "run()". /// \n - /// If you need more control on the execution, - /// first you must call \ref init(), then you can adda source node - /// with \ref addSource(). - /// Finally \ref start() will perform the actual path - /// computation. + /// If you need more control on the execution, first you must call + /// \ref lemon::BfsVisit::init() "init()", then you can add several + /// source nodes with \ref lemon::BfsVisit::addSource() "addSource()". + /// Finally \ref lemon::BfsVisit::start() "start()" will perform the + /// actual path computation. /// @{ + /// \brief Initializes the internal data structures. /// /// Initializes the internal data structures. - /// void init() { create_maps(); _list.resize(countNodes(*_digraph)); @@ -1381,7 +1444,7 @@ /// /// \return The processed node. /// - /// \pre The queue must not be empty! + /// \pre The queue must not be empty. Node processNextNode() { Node n = _list[++_list_front]; _visitor->process(n); @@ -1402,16 +1465,17 @@ /// \brief Processes the next node. /// - /// Processes the next node. And checks that the given target node + /// Processes the next node and checks if the given target node /// is reached. If the target node is reachable from the processed - /// node then the reached parameter will be set true. The reached - /// parameter should be initially false. + /// node, then the \c reach parameter will be set to \c true. /// /// \param target The target node. - /// \retval reach Indicates that the target node is reached. + /// \retval reach Indicates if the target node is reached. + /// It should be initially \c false. + /// /// \return The processed node. /// - /// \warning The queue must not be empty! + /// \pre The queue must not be empty. Node processNextNode(Node target, bool& reach) { Node n = _list[++_list_front]; _visitor->process(n); @@ -1433,16 +1497,19 @@ /// \brief Processes the next node. /// - /// Processes the next node. And checks that at least one of - /// reached node has true value in the \c nm node map. If one node - /// with true value is reachable from the processed node then the - /// rnode parameter will be set to the first of such nodes. + /// Processes the next node and checks if at least one of reached + /// nodes has \c true value in the \c nm node map. If one node + /// with \c true value is reachable from the processed node, then the + /// \c rnode parameter will be set to the first of such nodes. /// - /// \param nm The node map of possible targets. + /// \param nm A \c bool (or convertible) node map that indicates the + /// possible targets. /// \retval rnode The reached target node. + /// It should be initially \c INVALID. + /// /// \return The processed node. /// - /// \warning The queue must not be empty! + /// \pre The queue must not be empty. template Node processNextNode(const NM& nm, Node& rnode) { Node n = _list[++_list_front]; @@ -1463,44 +1530,71 @@ return n; } - /// \brief Next node to be processed. + /// \brief The next node to be processed. /// - /// Next node to be processed. - /// - /// \return The next node to be processed or INVALID if the stack is - /// empty. - Node nextNode() { + /// Returns the next node to be processed or \c INVALID if the queue + /// is empty. + Node nextNode() const { return _list_front != _list_back ? _list[_list_front + 1] : INVALID; } /// \brief Returns \c false if there are nodes - /// to be processed in the queue + /// to be processed. /// /// Returns \c false if there are nodes - /// to be processed in the queue - bool emptyQueue() { return _list_front == _list_back; } + /// to be processed in the queue. + bool emptyQueue() const { return _list_front == _list_back; } /// \brief Returns the number of the nodes to be processed. /// /// Returns the number of the nodes to be processed in the queue. - int queueSize() { return _list_back - _list_front; } + int queueSize() const { return _list_back - _list_front; } /// \brief Executes the algorithm. /// /// Executes the algorithm. /// - /// \pre init() must be called and at least one node should be added + /// This method runs the %BFS 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. + /// + /// \note b.start() is just a shortcut of the following code. + /// \code + /// while ( !b.emptyQueue() ) { + /// b.processNextNode(); + /// } + /// \endcode void start() { while ( !emptyQueue() ) processNextNode(); } - /// \brief Executes the algorithm until \c dest is reached. + /// \brief Executes the algorithm until the given target node is reached. /// - /// Executes the algorithm until \c dest is reached. + /// Executes the algorithm until the given target node is reached. /// - /// \pre init() must be called and at least one node should be added - /// with addSource() before using this function. + /// This method runs the %BFS algorithm from the root node(s) + /// in order to compute the shortest path to \c dest. + /// + /// The algorithm computes + /// - the shortest path to \c dest, + /// - the distance of \c dest from the root(s). + /// + /// \pre init() must be called and at least one root node should be + /// added with addSource() before using this function. + /// + /// \note b.start(t) is just a shortcut of the following code. + /// \code + /// bool reach = false; + /// while ( !b.emptyQueue() && !reach ) { + /// b.processNextNode(t, reach); + /// } + /// \endcode void start(Node dest) { bool reach = false; while ( !emptyQueue() && !reach ) processNextNode(dest, reach); @@ -1510,15 +1604,28 @@ /// /// Executes the algorithm until a condition is met. /// - /// \pre init() must be called and at least one node should be added - /// with addSource() before using this function. + /// This method runs the %BFS algorithm from the root node(s) in + /// order to compute the shortest path to a node \c v with + /// nm[v] true, if such a node can be found. /// - ///\param nm must be a bool (or convertible) node map. The - ///algorithm will stop when it reaches a node \c v with + /// \param nm must be a bool (or convertible) node map. The + /// algorithm will stop when it reaches a node \c v with /// nm[v] true. /// - ///\return The reached node \c v with nm[v] true or - ///\c INVALID if no such node was found. + /// \return The reached node \c v with nm[v] true or + /// \c INVALID if no such node was found. + /// + /// \pre init() must be called and at least one root node should be + /// added with addSource() before using this function. + /// + /// \note b.start(nm) is just a shortcut of the following code. + /// \code + /// Node rnode = INVALID; + /// while ( !b.emptyQueue() && rnode == INVALID ) { + /// b.processNextNode(nm, rnode); + /// } + /// return rnode; + /// \endcode template Node start(const NM &nm) { Node rnode = INVALID; @@ -1528,10 +1635,16 @@ return rnode; } - /// \brief Runs %BFSVisit algorithm from node \c s. + /// \brief Runs the algorithm from the given node. /// - /// This method runs the %BFS algorithm from a root node \c s. - /// \note b.run(s) is just a shortcut of the following code. + /// This method runs the %BFS algorithm from node \c s + /// in order to compute the shortest path to each node. + /// + /// The algorithm computes + /// - the shortest path tree, + /// - the distance of each node from the root. + /// + /// \note b.run(s) is just a shortcut of the following code. ///\code /// b.init(); /// b.addSource(s); @@ -1543,19 +1656,21 @@ start(); } - /// \brief Runs %BFSVisit algorithm to visit all nodes in the digraph. + /// \brief Runs the algorithm to visit all nodes in the digraph. /// /// This method runs the %BFS algorithm in order to - /// compute the %BFS path to each node. The algorithm computes - /// - The %BFS tree. - /// - The distance of each node from the root in the %BFS tree. + /// compute the shortest path to each node. /// - ///\note b.run() is just a shortcut of the following code. + /// The algorithm computes + /// - the shortest path tree (forest), + /// - the distance of each node from the root(s). + /// + /// \note b.run(s) is just a shortcut of the following code. ///\code /// b.init(); - /// for (NodeIt it(digraph); it != INVALID; ++it) { - /// if (!b.reached(it)) { - /// b.addSource(it); + /// for (NodeIt n(gr); n != INVALID; ++n) { + /// if (!b.reached(n)) { + /// b.addSource(n); /// b.start(); /// } /// } @@ -1569,27 +1684,28 @@ } } } + ///@} /// \name Query Functions /// The result of the %BFS algorithm can be obtained using these /// functions.\n - /// Before the use of these functions, - /// either run() or start() must be called. + /// Either \ref lemon::BfsVisit::run() "run()" or + /// \ref lemon::BfsVisit::start() "start()" must be called before + /// using them. ///@{ - /// \brief Checks if a node is reachable from the root. + /// \brief Checks if a node is reachable from the root(s). /// /// Returns \c true if \c v is reachable from the root(s). - /// \warning The source nodes are inditated as unreachable. /// \pre Either \ref run() or \ref start() /// must be called before using this function. - /// bool reached(Node v) { return (*_reached)[v]; } + ///@} + }; } //END OF NAMESPACE LEMON #endif -