diff -r c925a077cf73 -r d9205a711324 lemon/dag_shortest_path.h --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/lemon/dag_shortest_path.h Fri Jan 27 08:17:25 2006 +0000 @@ -0,0 +1,1082 @@ +/* -*- C++ -*- + * lemon/dag_shortest_path.h - Part of LEMON, a generic C++ optimization library + * + * Copyright (C) 2005 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_DAG_SHORTEST_PATH_H +#define LEMON_DAG_SHORTEST_PATH_H + +///\ingroup flowalgs +/// \file +/// \brief DagShortestPath algorithm. +/// + +#include +#include +#include +#include +#include + +#include + +namespace lemon { + + /// \brief Default OperationTraits for the DagShortestPath algorithm class. + /// + /// It defines all computational operations and constants which are + /// used in the dag shortest path algorithm. The default implementation + /// is based on the numeric_limits class. If the numeric type does not + /// have infinity value then the maximum value is used as extremal + /// infinity value. + template < + typename Value, + bool has_infinity = std::numeric_limits::has_infinity> + struct DagShortestPathDefaultOperationTraits { + /// \brief Gives back the zero value of the type. + static Value zero() { + return static_cast(0); + } + /// \brief Gives back the positive infinity value of the type. + static Value infinity() { + return std::numeric_limits::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 true only if the first value less than the second. + static bool less(const Value& left, const Value& right) { + return left < right; + } + }; + + template + struct DagShortestPathDefaultOperationTraits { + static Value zero() { + return static_cast(0); + } + static Value infinity() { + return std::numeric_limits::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 Default traits class of DagShortestPath class. + /// + /// Default traits class of DagShortestPath class. + /// \param _Graph Graph type. + /// \param _LegthMap Type of length map. + template + struct DagShortestPathDefaultTraits { + /// The graph type the algorithm runs on. + typedef _Graph Graph; + + /// \brief The type of the map that stores the edge lengths. + /// + /// The type of the map that stores the edge lengths. + /// It must meet the \ref concept::ReadMap "ReadMap" concept. + typedef _LengthMap LengthMap; + + // The type of the length of the edges. + typedef typename _LengthMap::Value Value; + + /// \brief Operation traits for dag shortest path algorithm. + /// + /// It defines the infinity type on the given Value type + /// and the used operation. + /// \see DagShortestPathDefaultOperationTraits + typedef DagShortestPathDefaultOperationTraits OperationTraits; + + /// \brief The type of the map that stores the last edges of the + /// shortest paths. + /// + /// The type of the map that stores the last + /// edges of the shortest paths. + /// It must meet the \ref concept::WriteMap "WriteMap" concept. + /// + typedef typename Graph::template NodeMap PredMap; + + /// \brief Instantiates a PredMap. + /// + /// This function instantiates a \ref PredMap. + /// \param G is the graph, to which we would like to define the PredMap. + /// \todo The graph alone may be insufficient for the initialization + static PredMap *createPredMap(const _Graph& graph) { + return new PredMap(graph); + } + + /// \brief The type of the map that stores the dists of the nodes. + /// + /// The type of the map that stores the dists of the nodes. + /// It must meet the \ref concept::WriteMap "WriteMap" concept. + /// + typedef typename Graph::template NodeMap + DistMap; + + /// \brief Instantiates a DistMap. + /// + /// This function instantiates a \ref DistMap. + /// \param G is the graph, to which we would like to define the + /// \ref DistMap + static DistMap *createDistMap(const _Graph& graph) { + return new DistMap(graph); + } + + }; + + /// \brief Inverse OperationTraits for the DagShortestPath algorithm class. + /// + /// It defines all computational operations and constants which are + /// used in the dag shortest path algorithm. It is the inverse of + /// \ref DagShortestPathDefaultOperationTraits, so it can be used to + /// calculate the longest path. The default implementation + /// is based on the numeric_limits class. If the numeric type does not + /// have infinity value then the minimum value is used as extremal + /// infinity value. + template < + typename Value, + bool has_infinity = std::numeric_limits::has_infinity> + struct DagLongestPathOperationTraits { + /// \brief Gives back the zero value of the type. + static Value zero() { + return static_cast(0); + } + /// \brief Gives back the negative infinity value of the type. + static Value infinity() { + return -(std::numeric_limits::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 true only if the first value less than the second. + static bool less(const Value& left, const Value& right) { + return left > right; + } + }; + + template + struct DagLongestPathOperationTraits { + static Value zero() { + return static_cast(0); + } + static Value infinity() { + return std::numeric_limits::min(); + } + 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 Inverse traits class of DagShortestPath class. + /// + /// Inverse traits class of DagShortestPath class. + /// \param _Graph Graph type. + /// \param _LegthMap Type of length map. + template + struct DagLongestPathTraits { + /// The graph type the algorithm runs on. + typedef _Graph Graph; + + /// \brief The type of the map that stores the edge lengths. + /// + /// The type of the map that stores the edge lengths. + /// It must meet the \ref concept::ReadMap "ReadMap" concept. + typedef _LengthMap LengthMap; + + // The type of the length of the edges. + typedef typename _LengthMap::Value Value; + + /// \brief Inverse operation traits for dag shortest path algorithm. + /// + /// It defines the infinity type on the given Value type + /// and the used operation. + /// \see DagLongestPathOperationTraits + typedef DagLongestPathOperationTraits OperationTraits; + + /// \brief The type of the map that stores the last edges of the + /// longest paths. + /// + /// The type of the map that stores the last + /// edges of the longest paths. + /// It must meet the \ref concept::WriteMap "WriteMap" concept. + /// + typedef typename Graph::template NodeMap PredMap; + + /// \brief Instantiates a PredMap. + /// + /// This function instantiates a \ref PredMap. + /// \param G is the graph, to which we would like to define the PredMap. + /// \todo The graph alone may be insufficient for the initialization + static PredMap *createPredMap(const _Graph& graph) { + return new PredMap(graph); + } + + /// \brief The type of the map that stores the dists of the nodes. + /// + /// The type of the map that stores the dists of the nodes. + /// It must meet the \ref concept::WriteMap "WriteMap" concept. + /// + typedef typename Graph::template NodeMap + DistMap; + + /// \brief Instantiates a DistMap. + /// + /// This function instantiates a \ref DistMap. + /// \param G is the graph, to which we would like to define the + /// \ref DistMap + static DistMap *createDistMap(const _Graph& graph) { + return new DistMap(graph); + } + + }; + + + /// \brief %DagShortestPath algorithm class. + /// + /// \ingroup flowalgs + /// This class provides an efficient implementation of a Dag sortest path + /// searching algorithm. The edge lengths are passed to the algorithm + /// using a \ref concept::ReadMap "ReadMap", so it is easy to change it + /// to any kind of length. + /// + /// The complexity of the algorithm is O(n + e). + /// + /// The type of the length is determined by the + /// \ref concept::ReadMap::Value "Value" of the length map. + /// + /// \param _Graph The graph type the algorithm runs on. The default value + /// is \ref ListGraph. The value of _Graph is not used directly by + /// DagShortestPath, it is only passed to \ref DagShortestPathDefaultTraits. + /// \param _LengthMap This read-only EdgeMap determines the lengths of the + /// edges. The default map type is \ref concept::StaticGraph::EdgeMap + /// "Graph::EdgeMap". The value of _LengthMap is not used directly + /// by DagShortestPath, it is only passed to \ref DagShortestPathDefaultTraits. + /// \param _Traits Traits class to set various data types used by the + /// algorithm. The default traits class is \ref DagShortestPathDefaultTraits + /// "DagShortestPathDefaultTraits<_Graph,_LengthMap>". See \ref + /// DagShortestPathDefaultTraits for the documentation of a DagShortestPath traits + /// class. + /// + /// \author Balazs Attila Mihaly (based on Balazs Dezso's work) + +#ifdef DOXYGEN + template +#else + template , + typename _Traits=DagShortestPathDefaultTraits<_Graph,_LengthMap> > +#endif + class DagShortestPath { + public: + + /// \brief \ref Exception for uninitialized parameters. + /// + /// This error represents problems in the initialization + /// of the parameters of the algorithms. + + class UninitializedParameter : public lemon::UninitializedParameter { + public: + virtual const char* exceptionName() const { + return "lemon::DagShortestPath::UninitializedParameter"; + } + }; + + typedef _Traits Traits; + ///The type of the underlying graph. + typedef typename _Traits::Graph Graph; + + typedef typename Graph::Node Node; + typedef typename Graph::NodeIt NodeIt; + typedef typename Graph::Edge Edge; + typedef typename Graph::EdgeIt EdgeIt; + typedef typename Graph::OutEdgeIt OutEdgeIt; + + /// \brief The type of the length of the edges. + typedef typename _Traits::LengthMap::Value Value; + /// \brief The type of the map that stores the edge lengths. + typedef typename _Traits::LengthMap LengthMap; + /// \brief The type of the map that stores the last + /// edges of the shortest paths. + typedef typename _Traits::PredMap PredMap; + /// \brief The type of the map that stores the dists of the nodes. + typedef typename _Traits::DistMap DistMap; + /// \brief The operation traits. + typedef typename _Traits::OperationTraits OperationTraits; + /// \brief The Node weight map. + typedef typename Graph::NodeMap WeightMap; + private: + /// Pointer to the underlying graph + const Graph *graph; + /// Pointer to the length map + const LengthMap *length; + ///Pointer to the map of predecessors edges + PredMap *_pred; + ///Indicates if \ref _pred is locally allocated (\c true) or not + bool local_pred; + ///Pointer to the map of distances + DistMap *_dist; + ///Indicates if \ref _dist is locally allocated (\c true) or not + bool local_dist; + ///Process step counter + unsigned int _process_step; + + std::vector _node_order; + + /// Creates the maps if necessary. + void create_maps() { + if(!_pred) { + local_pred = true; + _pred = Traits::createPredMap(*graph); + } + if(!_dist) { + local_dist = true; + _dist = Traits::createDistMap(*graph); + } + } + + public : + + typedef DagShortestPath Create; + + /// \name Named template parameters + + ///@{ + + template + struct DefPredMapTraits : public Traits { + typedef T PredMap; + static PredMap *createPredMap(const Graph&) { + throw UninitializedParameter(); + } + }; + + /// \brief \ref named-templ-param "Named parameter" for setting PredMap + /// type + /// \ref named-templ-param "Named parameter" for setting PredMap type + /// + template + struct DefPredMap { + typedef DagShortestPath< Graph, LengthMap, DefPredMapTraits > Create; + }; + + template + struct DefDistMapTraits : public Traits { + typedef T DistMap; + static DistMap *createDistMap(const Graph& graph) { + throw UninitializedParameter(); + } + }; + + /// \brief \ref named-templ-param "Named parameter" for setting DistMap + /// type + /// + /// \ref named-templ-param "Named parameter" for setting DistMap type + /// + template + struct DefDistMap + : public DagShortestPath< Graph, LengthMap, DefDistMapTraits > { + typedef DagShortestPath< Graph, LengthMap, DefDistMapTraits > Create; + }; + + template + struct DefOperationTraitsTraits : public Traits { + typedef T OperationTraits; + }; + + /// \brief \ref named-templ-param "Named parameter" for setting + /// OperationTraits type + /// + /// \ref named-templ-param "Named parameter" for setting OperationTraits + /// type + template + struct DefOperationTraits + : public DagShortestPath< Graph, LengthMap, DefOperationTraitsTraits > { + typedef DagShortestPath< Graph, LengthMap, DefOperationTraitsTraits > + Create; + }; + + ///@} + + protected: + + DagShortestPath() {} + + public: + + /// \brief Constructor. + /// + /// \param _graph the graph the algorithm will run on. + /// \param _length the length map used by the algorithm. + DagShortestPath(const Graph& _graph, const LengthMap& _length) : + graph(&_graph), length(&_length), + _pred(0), local_pred(false), + _dist(0), local_dist(false){} + + /// \brief Constructor with node weight map. + /// + /// \param _graph the graph the algorithm will run on. + /// \param _length the length map used by the algorithm. + /// The NodeMap _length will be used as the weight map. + /// Each edge will have the weight of its target node. + DagShortestPath(const Graph& _graph, const WeightMap& _length) : + graph(&_graph), + _pred(0), local_pred(false), + _dist(0), local_dist(false){ + length=new LengthMap(_graph); + _dist=new DistMap(_graph); + for(EdgeIt eit(_graph);eit!=INVALID;++eit) + (const_cast(length))->set(eit,_length[_graph.target(eit)]); + } + + ///Destructor. + ~DagShortestPath() { + if(local_pred) delete _pred; + if(local_dist) delete _dist; + } + + /// \brief Sets the length map. + /// + /// Sets the length map. + /// \return \c (*this) + DagShortestPath &lengthMap(const LengthMap &m) { + length = &m; + return *this; + } + + /// \brief Sets the map storing the predecessor edges. + /// + /// Sets the map storing the predecessor edges. + /// If you don't use this function before calling \ref run(), + /// it will allocate one. The destuctor deallocates this + /// automatically allocated map, of course. + /// \return \c (*this) + DagShortestPath &predMap(PredMap &m) { + if(local_pred) { + delete _pred; + local_pred=false; + } + _pred = &m; + return *this; + } + + /// \brief Sets the map storing the distances calculated by the algorithm. + /// + /// Sets the map storing the distances calculated by the algorithm. + /// If you don't use this function before calling \ref run(), + /// it will allocate one. The destuctor deallocates this + /// automatically allocated map, of course. + /// \return \c (*this) + DagShortestPath &distMap(DistMap &m) { + if(local_dist) { + delete _dist; + local_dist=false; + } + _dist = &m; + return *this; + } + + /// \name Execution control + /// The simplest way to execute the algorithm is to use + /// one of the member functions called \c 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. + /// Some functions have an alternative form (\ref checkedInit(...), + /// \ref checkedRun(...)) which also verifies if the graph given in the + /// constructor is a dag. + + ///@{ + + /// \brief Initializes the internal data structures. + /// + /// Initializes the internal data structures. + void init(const Value value = OperationTraits::infinity()) { + typedef typename Graph::template NodeMap NodeOrderMap; + _process_step=0; + NodeOrderMap node_order(*graph); + topologicalSort(*graph,node_order); + _node_order.resize(countNodes(*graph),INVALID); + create_maps(); + for (NodeIt it(*graph); it != INVALID; ++it) { + _node_order[node_order[it]]=it; + _pred->set(it, INVALID); + _dist->set(it, value); + } + } + + /// \brief Initializes the internal data structures + /// with a given topological sort (NodeMap). + /// + /// Initializes the internal data structures + /// with a given topological sort (NodeMap). + void init(const typename Graph::template NodeMap& node_order, + const Value value = OperationTraits::infinity()) { + _process_step=0; + _node_order.resize(countNodes(*graph),INVALID); + create_maps(); + for (NodeIt it(*graph); it != INVALID; ++it) { + _node_order[node_order[it]]=it; + _pred->set(it, INVALID); + _dist->set(it, value); + } + } + + /// \brief Initializes the internal data structures + /// with a given topological sort (std::vector). + /// + /// Initializes the internal data structures + /// with a given topological sort (std::vector). + void init(const std::vector& node_order, + const Value value = OperationTraits::infinity()) { + _process_step=0; + _node_order=node_order; + create_maps(); + for (NodeIt it(*graph); it != INVALID; ++it) { + _pred->set(it, INVALID); + _dist->set(it, value); + } + } + + /// \brief Initializes the internal data structures. It also checks if the graph is dag. + /// + /// Initializes the internal data structures. It also checks if the graph is dag. + /// \return true if the graph (given in the constructor) is dag, false otherwise. + bool checkedInit(const Value value = OperationTraits::infinity()) { + typedef typename Graph::template NodeMap NodeOrderMap; + NodeOrderMap node_order(*graph); + if(!checkedTopologicalSort(*graph,node_order))return false; + init(node_order,value); + return true; + } + + /// \brief Initializes the internal data structures with a given + /// topological sort (NodeMap). It also checks if the graph is dag. + /// + /// Initializes the internal data structures with a given + /// topological sort (NodeMap). It also checks if the graph is dag. + /// \return true if the graph (given in the constructor) is dag, false otherwise. + bool checkedInit(const typename Graph::template NodeMap& node_order, + const Value value = OperationTraits::infinity()) { + for(NodeIt it(*graph);it!=INVALID;++it){ + for(OutEdgeIt oeit(*graph,it);oeit!=INVALID;++oeit){ + if(node_order[graph->target(oeit)]& node_order, + const Value value = OperationTraits::infinity()) { + typedef typename Graph::template NodeMap BoolNodeMap; + BoolNodeMap _processed(*graph,false); + for(unsigned int i=0;i<_node_order.size();++i){ + _processed[node_order[i]]=true; + for(OutEdgeIt oeit(*graph,node_order[i]);oeit!=INVALID;++oeit){ + if(_processed[graph->target(oeit)])return false; + } + } + init(node_order,value); + return true; + } + + /// \brief Adds a new source node. + /// + /// The optional second parameter is the initial distance of the node. + /// It just sets the distance of the node to the given value. + void addSource(Node source, Value dst = OperationTraits::zero()) { + if((*_dist)[source] != dst){ + _dist->set(source, dst); + } + } + + /// \brief Executes one step from the dag shortest path algorithm. + /// + /// If the algoritm calculated the distances in the previous step + /// strictly for all at most k length paths then it will calculate the + /// distances strictly for all at most k + 1 length paths. With k + /// iteration this function calculates the at most k length paths. + ///\pre the queue is not empty + ///\return the currently processed node + Node processNextNode() { + if(reached(_node_order[_process_step])){ + for (OutEdgeIt it(*graph, _node_order[_process_step]); it != INVALID; ++it) { + Node target = graph->target(it); + Value relaxed = + OperationTraits::plus((*_dist)[_node_order[_process_step]], (*length)[it]); + if (OperationTraits::less(relaxed, (*_dist)[target])) { + _pred->set(target, it); + _dist->set(target, relaxed); + } + } + } + ++_process_step; + return _node_order[_process_step-1]; + } + + ///\brief Returns \c false if there are nodes + ///to be processed in the queue + /// + ///Returns \c false if there are nodes + ///to be processed in the queue + bool emptyQueue() { return _node_order.size()-1==_process_step; } + + ///\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 _node_order.size()-1-_process_step; } + + /// \brief 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 %DagShortestPath 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). + void start() { + while(!emptyQueue()) { + processNextNode(); + } + } + + /// \brief Runs %DagShortestPath algorithm from node \c s. + /// + /// This method runs the %DagShortestPath 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. + /// + /// \note d.run(s) is just a shortcut of the following code. + /// \code + /// d.init(); + /// d.addSource(s); + /// d.start(); + /// \endcode + void run(Node s) { + init(); + addSource(s); + start(); + } + + /// \brief Runs %DagShortestPath algorithm from node \c s. + /// It also checks if the graph is a dag. + /// + /// This method runs the %DagShortestPath 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. + /// The algorithm checks if the graph given int the constructor is a dag. + bool checkedRun(Node s) { + if(!checkedInit())return false; + addSource(s); + start(); + return true; + } + + ///@} + + /// \name Query Functions + /// The result of the %DagShortestPath algorithm can be obtained using these + /// functions.\n + /// Before the use of these functions, + /// either run() or start() must be called. + + ///@{ + + /// \brief Copies the shortest path to \c t into \c p + /// + /// This function copies the shortest path to \c t into \c p. + /// If it \c t is a source itself or unreachable, then it does not + /// alter \c p. + /// + /// \return Returns \c true if a path to \c t was actually copied to \c p, + /// \c false otherwise. + /// \sa DirPath + template + bool getPath(Path &p, Node t) { + if(reached(t)) { + p.clear(); + typename Path::Builder b(p); + for(b.setStartNode(t);predEdge(t)!=INVALID;t=predNode(t)) + b.pushFront(predEdge(t)); + b.commit(); + return true; + } + return false; + } + + /// \brief The distance of a node from the root. + /// + /// Returns the distance of a node from the root. + /// \pre \ref run() must be called before using this function. + /// \warning If node \c v in unreachable from the root the return value + /// of this funcion is undefined. + Value dist(Node v) const { return (*_dist)[v]; } + + /// \brief Returns the 'previous edge' of the shortest path tree. + /// + /// For a node \c v it returns the 'previous edge' of the shortest path + /// tree, i.e. it returns the last edge of a shortest path from the root + /// to \c v. It is \ref INVALID if \c v is unreachable from the root or + /// if \c v=s. The shortest path tree used here is equal to the shortest + /// path tree used in \ref predNode(). + /// \pre \ref run() must be called before using + /// this function. + Edge predEdge(Node v) const { return (*_pred)[v]; } + + /// \brief Returns the 'previous node' of the shortest path tree. + /// + /// 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 to \c /v. It is INVALID if \c v is unreachable from the root + /// or if \c v=s. The shortest path tree used here is equal to the + /// shortest path tree used in \ref predEdge(). \pre \ref run() must be + /// called before using this function. + Node predNode(Node v) const { + return (*_pred)[v] == INVALID ? INVALID : graph->source((*_pred)[v]); + } + + /// \brief Returns a reference to the NodeMap of distances. + /// + /// Returns a reference to the NodeMap of distances. \pre \ref run() must + /// be called before using this function. + const DistMap &distMap() const { return *_dist;} + + /// \brief Returns a reference to the shortest path tree map. + /// + /// Returns a reference to the NodeMap of the edges of the + /// shortest path tree. + /// \pre \ref run() must be called before using this function. + const PredMap &predMap() const { return *_pred; } + + /// \brief Checks if a node is reachable from the root. + /// + /// Returns \c true if \c v is reachable from the root. + /// \pre \ref run() must be called before using this function. + /// + bool reached(Node v) { return (*_dist)[v] != OperationTraits::infinity(); } + + ///@} + }; + + /// \brief Default traits class of DagShortestPath function. + /// + /// Default traits class of DagShortestPath function. + /// \param _Graph Graph type. + /// \param _LengthMap Type of length map. + template + struct DagShortestPathWizardDefaultTraits { + /// \brief The graph type the algorithm runs on. + typedef _Graph Graph; + + /// \brief The type of the map that stores the edge lengths. + /// + /// The type of the map that stores the edge lengths. + /// It must meet the \ref concept::ReadMap "ReadMap" concept. + typedef _LengthMap LengthMap; + + /// \brief The value type of the length map. + typedef typename _LengthMap::Value Value; + + /// \brief Operation traits for dag shortest path algorithm. + /// + /// It defines the infinity type on the given Value type + /// and the used operation. + /// \see DagShortestPathDefaultOperationTraits + typedef DagShortestPathDefaultOperationTraits OperationTraits; + + /// \brief The type of the map that stores the last + /// edges of the shortest paths. + /// + /// The type of the map that stores the last + /// edges of the shortest paths. + /// It must meet the \ref concept::WriteMap "WriteMap" concept. + typedef NullMap PredMap; + + /// \brief Instantiates a PredMap. + /// + /// This function instantiates a \ref PredMap. + static PredMap *createPredMap(const _Graph &) { + return new PredMap(); + } + /// \brief The type of the map that stores the dists of the nodes. + /// + /// The type of the map that stores the dists of the nodes. + /// It must meet the \ref concept::WriteMap "WriteMap" concept. + typedef NullMap DistMap; + /// \brief Instantiates a DistMap. + /// + /// This function instantiates a \ref DistMap. + static DistMap *createDistMap(const _Graph &) { + return new DistMap(); + } + }; + + /// \brief Default traits used by \ref DagShortestPathWizard + /// + /// To make it easier to use DagShortestPath algorithm + /// we have created a wizard class. + /// This \ref DagShortestPathWizard class needs default traits, + /// as well as the \ref DagShortestPath class. + /// The \ref DagShortestPathWizardBase is a class to be the default traits of the + /// \ref DagShortestPathWizard class. + /// \todo More named parameters are required... + template + class DagShortestPathWizardBase + : public DagShortestPathWizardDefaultTraits<_Graph,_LengthMap> { + + typedef DagShortestPathWizardDefaultTraits<_Graph,_LengthMap> Base; + protected: + /// Type of the nodes in the graph. + typedef typename Base::Graph::Node Node; + + /// Pointer to the underlying graph. + void *_graph; + /// Pointer to the length map + void *_length; + ///Pointer to the map of predecessors edges. + void *_pred; + ///Pointer to the map of distances. + void *_dist; + ///Pointer to the source node. + Node _source; + + public: + /// Constructor. + + /// This constructor does not require parameters, therefore it initiates + /// all of the attributes to default values (0, INVALID). + DagShortestPathWizardBase() : _graph(0), _length(0), _pred(0), + _dist(0), _source(INVALID) {} + + /// Constructor. + + /// This constructor requires some parameters, + /// listed in the parameters list. + /// Others are initiated to 0. + /// \param graph is the initial value of \ref _graph + /// \param length is the initial value of \ref _length + /// \param source is the initial value of \ref _source + DagShortestPathWizardBase(const _Graph& graph, + const _LengthMap& length, + Node source = INVALID) : + _graph((void *)&graph), _length((void *)&length), _pred(0), + _dist(0), _source(source) {} + + }; + + /// A class to make the usage of DagShortestPath algorithm easier + + /// This class is created to make it easier to use DagShortestPath algorithm. + /// It uses the functions and features of the plain \ref DagShortestPath, + /// but it is much simpler to use it. + /// + /// Simplicity means that the way to change the types defined + /// in the traits class is based on functions that returns the new class + /// and not on templatable built-in classes. + /// When using the plain \ref DagShortestPath + /// the new class with the modified type comes from + /// the original class by using the :: + /// operator. In the case of \ref DagShortestPathWizard only + /// 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 DagShortestPath class, and calls the \ref + /// DagShortestPath::run() method of it. + template + class DagShortestPathWizard : public _Traits { + typedef _Traits Base; + + ///The type of the underlying graph. + typedef typename _Traits::Graph Graph; + + typedef typename Graph::Node Node; + typedef typename Graph::NodeIt NodeIt; + typedef typename Graph::Edge Edge; + typedef typename Graph::OutEdgeIt EdgeIt; + + ///The type of the map that stores the edge lengths. + typedef typename _Traits::LengthMap LengthMap; + + ///The type of the length of the edges. + typedef typename LengthMap::Value Value; + + ///\brief The type of the map that stores the last + ///edges of the shortest paths. + typedef typename _Traits::PredMap PredMap; + + ///The type of the map that stores the dists of the nodes. + typedef typename _Traits::DistMap DistMap; + + public: + /// Constructor. + DagShortestPathWizard() : _Traits() {} + + /// \brief Constructor that requires parameters. + /// + /// Constructor that requires parameters. + /// These parameters will be the default values for the traits class. + DagShortestPathWizard(const Graph& graph, const LengthMap& length, + Node source = INVALID) + : _Traits(graph, length, source) {} + + /// \brief Copy constructor + DagShortestPathWizard(const _Traits &b) : _Traits(b) {} + + ~DagShortestPathWizard() {} + + /// \brief Runs DagShortestPath algorithm from a given node. + /// + /// Runs DagShortestPath algorithm from a given node. + /// The node can be given by the \ref source function. + void run() { + if(Base::_source == INVALID) throw UninitializedParameter(); + DagShortestPath + bf(*(Graph*)Base::_graph, *(LengthMap*)Base::_length); + if (Base::_pred) bf.predMap(*(PredMap*)Base::_pred); + if (Base::_dist) bf.distMap(*(DistMap*)Base::_dist); + bf.run(Base::_source); + } + + /// \brief Runs DagShortestPath algorithm from the given node. + /// + /// Runs DagShortestPath algorithm from the given node. + /// \param s is the given source. + void run(Node source) { + Base::_source = source; + run(); + } + + template + struct DefPredMapBase : public Base { + typedef T PredMap; + static PredMap *createPredMap(const Graph &) { return 0; }; + DefPredMapBase(const _Traits &b) : _Traits(b) {} + }; + + ///\brief \ref named-templ-param "Named parameter" + ///function for setting PredMap type + /// + /// \ref named-templ-param "Named parameter" + ///function for setting PredMap type + /// + template + DagShortestPathWizard > predMap(const T &t) + { + Base::_pred=(void *)&t; + return DagShortestPathWizard >(*this); + } + + template + struct DefDistMapBase : public Base { + typedef T DistMap; + static DistMap *createDistMap(const Graph &) { return 0; }; + DefDistMapBase(const _Traits &b) : _Traits(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 + DagShortestPathWizard > distMap(const T &t) { + Base::_dist=(void *)&t; + return DagShortestPathWizard >(*this); + } + + template + struct DefOperationTraitsBase : public Base { + typedef T OperationTraits; + DefOperationTraitsBase(const _Traits &b) : _Traits(b) {} + }; + + ///\brief \ref named-templ-param "Named parameter" + ///function for setting OperationTraits type + /// + /// \ref named-templ-param "Named parameter" + ///function for setting OperationTraits type + /// + template + DagShortestPathWizard > distMap() { + return DagShortestPathWizard >(*this); + } + + /// \brief Sets the source node, from which the DagShortestPath algorithm runs. + /// + /// Sets the source node, from which the DagShortestPath algorithm runs. + /// \param s is the source node. + DagShortestPathWizard<_Traits>& source(Node source) { + Base::_source = source; + return *this; + } + + }; + + /// \brief Function type interface for DagShortestPath algorithm. + /// + /// \ingroup flowalgs + /// Function type interface for DagShortestPath algorithm. + /// + /// This function also has several \ref named-templ-func-param + /// "named parameters", they are declared as the members of class + /// \ref DagShortestPathWizard. + /// The following + /// example shows how to use these parameters. + /// \code + /// dagShortestPath(g,length,source).predMap(preds).run(); + /// \endcode + /// \warning Don't forget to put the \ref DagShortestPathWizard::run() "run()" + /// to the end of the parameter list. + /// \sa DagShortestPathWizard + /// \sa DagShortestPath + template + DagShortestPathWizard > + dagShortestPath(const _Graph& graph, + const _LengthMap& length, + typename _Graph::Node source = INVALID) { + return DagShortestPathWizard > + (graph, length, source); + } + +} //END OF NAMESPACE LEMON + +#endif +