[Lemon-commits] [lemon_svn] deba: r2225 - hugo/trunk/lemon
Lemon SVN
svn at lemon.cs.elte.hu
Mon Nov 6 20:51:04 CET 2006
Author: deba
Date: Mon Oct 3 12:20:56 2005
New Revision: 2225
Added:
hugo/trunk/lemon/belmann_ford.h
hugo/trunk/lemon/floyd_warshall.h
hugo/trunk/lemon/johnson.h
Log:
Some shortest path algorithms
All-pair-shortest path algorithms without function interface
we may need it
Added: hugo/trunk/lemon/belmann_ford.h
==============================================================================
--- (empty file)
+++ hugo/trunk/lemon/belmann_ford.h Mon Oct 3 12:20:56 2005
@@ -0,0 +1,784 @@
+/* -*- C++ -*-
+ * lemon/belmann_ford.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_BELMANN_FORD_H
+#define LEMON_BELMANN_FORD_H
+
+///\ingroup flowalgs
+/// \file
+/// \brief BelmannFord algorithm.
+///
+/// \todo getPath() should be implemented! (also for BFS and DFS)
+
+#include <lemon/list_graph.h>
+#include <lemon/invalid.h>
+#include <lemon/error.h>
+#include <lemon/maps.h>
+
+#include <limits>
+
+namespace lemon {
+
+ /// \brief Default OperationTraits for the BelmannFord algorithm class.
+ ///
+ /// It defines all computational operations and constants which are
+ /// used in the belmann ford 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<Value>::has_infinity>
+ struct BelmannFordDefaultOperationTraits {
+ /// \brief Gives back the zero value of the type.
+ static Value zero() {
+ return static_cast<Value>(0);
+ }
+ /// \brief Gives back the positive infinity value of the type.
+ static Value infinity() {
+ return std::numeric_limits<Value>::infinity();
+ }
+ /// \brief Gives back the sum of the given two elements.
+ static Value plus(const Value& left, const Value& right) {
+ return left + right;
+ }
+ /// \brief Gives back true only if the first value less than the second.
+ static bool less(const Value& left, const Value& right) {
+ return left < right;
+ }
+ };
+
+ template <typename Value>
+ struct BelmannFordDefaultOperationTraits<Value, false> {
+ static Value zero() {
+ return static_cast<Value>(0);
+ }
+ static Value infinity() {
+ return std::numeric_limits<Value>::max();
+ }
+ static Value plus(const Value& left, const Value& right) {
+ if (left == infinity() || right == infinity()) return infinity();
+ return left + right;
+ }
+ static bool less(const Value& left, const Value& right) {
+ return left < right;
+ }
+ };
+
+ /// \brief Default traits class of BelmannFord class.
+ ///
+ /// Default traits class of BelmannFord class.
+ /// \param _Graph Graph type.
+ /// \param _LegthMap Type of length map.
+ template<class _Graph, class _LengthMap>
+ struct BelmannFordDefaultTraits {
+ /// 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 belmann-ford algorithm.
+ ///
+ /// It defines the infinity type on the given Value type
+ /// and the used operation.
+ /// \see BelmannFordDefaultOperationTraits
+ typedef BelmannFordDefaultOperationTraits<Value> 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<typename _Graph::Edge> 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<typename _LengthMap::Value>
+ 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 BelmannFord algorithm class.
+ ///
+ /// \ingroup flowalgs
+ /// This class provides an efficient implementation of \c BelmannFord
+ /// 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 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
+ /// BelmannFord, it is only passed to \ref BelmannFordDefaultTraits.
+ /// \param _LengthMap This read-only EdgeMap determines the lengths of the
+ /// edges. The default map type is \ref concept::StaticGraph::EdgeMap
+ /// "Graph::EdgeMap<int>". The value of _LengthMap is not used directly
+ /// by BelmannFord, it is only passed to \ref BelmannFordDefaultTraits.
+ /// \param _Traits Traits class to set various data types used by the
+ /// algorithm. The default traits class is \ref BelmannFordDefaultTraits
+ /// "BelmannFordDefaultTraits<_Graph,_LengthMap>". See \ref
+ /// BelmannFordDefaultTraits for the documentation of a BelmannFord traits
+ /// class.
+ ///
+ /// \author Balazs Dezso
+
+ template <typename _Graph=ListGraph,
+ typename _LengthMap=typename _Graph::template EdgeMap<int>,
+ typename _Traits=BelmannFordDefaultTraits<_Graph,_LengthMap> >
+ class BelmannFord {
+ 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::BelmannFord::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;
+
+ /// \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;
+ 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;
+
+ /// 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 :
+
+ /// \name Named template parameters
+
+ ///@{
+
+ template <class T>
+ struct DefPredMapTraits : public Traits {
+ typedef T PredMap;
+ static PredMap *createPredMap(const Graph& 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 <class T>
+ class DefPredMap
+ : public BelmannFord< Graph, LengthMap, DefPredMapTraits<T> > {};
+
+ template <class T>
+ 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 <class T>
+ class DefDistMap
+ : public BelmannFord< Graph, LengthMap, DefDistMapTraits<T> > {};
+
+ template <class T>
+ 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 PredMap type
+ template <class T>
+ class DefOperationTraits
+ : public BelmannFord< Graph, LengthMap, DefOperationTraitsTraits<T> > {
+ public:
+ typedef BelmannFord< Graph, LengthMap, DefOperationTraitsTraits<T> >
+ BelmannFord;
+ };
+
+ ///@}
+
+ public:
+
+ /// \brief Constructor.
+ ///
+ /// \param _graph the graph the algorithm will run on.
+ /// \param _length the length map used by the algorithm.
+ BelmannFord(const Graph& _graph, const LengthMap& _length) :
+ graph(&_graph), length(&_length),
+ _pred(0), local_pred(false),
+ _dist(0), local_dist(false) {}
+
+ ///Destructor.
+ ~BelmannFord() {
+ if(local_pred) delete _pred;
+ if(local_dist) delete _dist;
+ }
+
+ /// \brief Sets the length map.
+ ///
+ /// Sets the length map.
+ /// \return \c (*this)
+ BelmannFord &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)
+ BelmannFord &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)
+ BelmannFord &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.
+
+ ///@{
+
+ /// \brief Initializes the internal data structures.
+ ///
+ /// Initializes the internal data structures.
+ void init() {
+ create_maps();
+ for (NodeIt it(*graph); it != INVALID; ++it) {
+ _pred->set(it, INVALID);
+ _dist->set(it, OperationTraits::infinity());
+ }
+ }
+
+ /// \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()) {
+ _dist->set(source, dst);
+ }
+
+ /// \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 %BelmannFord 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() {
+ bool ready = false;
+ while (!ready) {
+ ready = true;
+ for (EdgeIt it(*graph); it != INVALID; ++it) {
+ Node source = graph->source(it);
+ Node target = graph->target(it);
+ Value relaxed =
+ OperationTraits::plus((*_dist)[source], (*length)[it]);
+ if (OperationTraits::less(relaxed, (*_dist)[target])) {
+ _pred->set(target, it);
+ _dist->set(target, relaxed);
+ ready = false;
+ }
+ }
+ }
+ }
+
+ /// \brief Runs %BelmannFord algorithm from node \c s.
+ ///
+ /// This method runs the %BelmannFord 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();
+ }
+
+ ///@}
+
+ /// \name Query Functions
+ /// The result of the %BelmannFord 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.
+ /// \todo Is it the right way to handle unreachable nodes?
+ /// \return Returns \c true if a path to \c t was actually copied to \c p,
+ /// \c false otherwise.
+ /// \sa DirPath
+ template <typename Path>
+ bool getPath(Path &p, Node t) {
+ if(reached(t)) {
+ p.clear();
+ typename Path::Builder b(p);
+ for(b.setStartNode(t);pred(t)!=INVALID;t=predNode(t))
+ b.pushFront(pred(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.
+ /// \todo predEdge could be a better name.
+ Edge pred(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 pred(). \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 BelmannFord function.
+ ///
+ /// Default traits class of BelmannFord function.
+ /// \param _Graph Graph type.
+ /// \param _LengthMap Type of length map.
+ template <typename _Graph, typename _LengthMap>
+ struct BelmannFordWizardDefaultTraits {
+ /// \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 belmann-ford algorithm.
+ ///
+ /// It defines the infinity type on the given Value type
+ /// and the used operation.
+ /// \see BelmannFordDefaultOperationTraits
+ typedef BelmannFordDefaultOperationTraits<Value> 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 <typename _Graph::Node,typename _Graph::Edge> 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<typename Graph::Node, Value> 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 BelmannFordWizard
+ ///
+ /// To make it easier to use BelmannFord algorithm
+ /// we have created a wizard class.
+ /// This \ref BelmannFordWizard class needs default traits,
+ /// as well as the \ref BelmannFord class.
+ /// The \ref BelmannFordWizardBase is a class to be the default traits of the
+ /// \ref BelmannFordWizard class.
+ /// \todo More named parameters are required...
+ template<class _Graph,class _LengthMap>
+ class BelmannFordWizardBase
+ : public BelmannFordWizardDefaultTraits<_Graph,_LengthMap> {
+
+ typedef BelmannFordWizardDefaultTraits<_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).
+ BelmannFordWizardBase() : _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
+ BelmannFordWizardBase(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 BelmannFord algorithm easier
+
+ /// This class is created to make it easier to use BelmannFord algorithm.
+ /// It uses the functions and features of the plain \ref BelmannFord,
+ /// 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 BelmannFord
+ /// the new class with the modified type comes from
+ /// the original class by using the ::
+ /// operator. In the case of \ref BelmannFordWizard 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 BelmannFord class, and calls the \ref
+ /// BelmannFord::run method of it.
+ template<class _Traits>
+ class BelmannFordWizard : 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.
+ BelmannFordWizard() : _Traits() {}
+
+ /// \brief Constructor that requires parameters.
+ ///
+ /// Constructor that requires parameters.
+ /// These parameters will be the default values for the traits class.
+ BelmannFordWizard(const Graph& graph, const LengthMap& length,
+ Node source = INVALID)
+ : _Traits(graph, length, source) {}
+
+ /// \brief Copy constructor
+ BelmannFordWizard(const _Traits &b) : _Traits(b) {}
+
+ ~BelmannFordWizard() {}
+
+ /// \brief Runs BelmannFord algorithm from a given node.
+ ///
+ /// Runs BelmannFord algorithm from a given node.
+ /// The node can be given by the \ref source function.
+ void run() {
+ if(Base::_source == INVALID) throw UninitializedParameter();
+ BelmannFord<Graph,LengthMap,_Traits>
+ 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 BelmannFord algorithm from the given node.
+ ///
+ /// Runs BelmannFord algorithm from the given node.
+ /// \param s is the given source.
+ void run(Node source) {
+ Base::_source = source;
+ run();
+ }
+
+ template<class T>
+ 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<class T>
+ BelmannFordWizard<DefPredMapBase<T> > predMap(const T &t)
+ {
+ Base::_pred=(void *)&t;
+ return BelmannFordWizard<DefPredMapBase<T> >(*this);
+ }
+
+ template<class T>
+ 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<class T>
+ BelmannFordWizard<DefDistMapBase<T> > distMap(const T &t) {
+ Base::_dist=(void *)&t;
+ return BelmannFordWizard<DefDistMapBase<T> >(*this);
+ }
+
+ /// \brief Sets the source node, from which the BelmannFord algorithm runs.
+ ///
+ /// Sets the source node, from which the BelmannFord algorithm runs.
+ /// \param s is the source node.
+ BelmannFordWizard<_Traits>& source(Node source) {
+ Base::_source = source;
+ return *this;
+ }
+
+ };
+
+ /// \brief Function type interface for BelmannFord algorithm.
+ ///
+ /// \ingroup flowalgs
+ /// Function type interface for BelmannFord algorithm.
+ ///
+ /// This function also has several \ref named-templ-func-param
+ /// "named parameters", they are declared as the members of class
+ /// \ref BelmannFordWizard.
+ /// The following
+ /// example shows how to use these parameters.
+ /// \code
+ /// belmannford(g,length,source).predMap(preds).run();
+ /// \endcode
+ /// \warning Don't forget to put the \ref BelmannFordWizard::run() "run()"
+ /// to the end of the parameter list.
+ /// \sa BelmannFordWizard
+ /// \sa BelmannFord
+ template<class _Graph, class _LengthMap>
+ BelmannFordWizard<BelmannFordWizardBase<_Graph,_LengthMap> >
+ belmannFord(const _Graph& graph,
+ const _LengthMap& length,
+ typename _Graph::Node source = INVALID) {
+ return BelmannFordWizard<BelmannFordWizardBase<_Graph,_LengthMap> >
+ (graph, length, source);
+ }
+
+} //END OF NAMESPACE LEMON
+
+#endif
+
Added: hugo/trunk/lemon/floyd_warshall.h
==============================================================================
--- (empty file)
+++ hugo/trunk/lemon/floyd_warshall.h Mon Oct 3 12:20:56 2005
@@ -0,0 +1,525 @@
+/* -*- C++ -*-
+ * lemon/floyd_warshall.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_FLOYD_WARSHALL_H
+#define LEMON_FLOYD_WARSHALL_H
+
+///\ingroup flowalgs
+/// \file
+/// \brief FloydWarshall algorithm.
+///
+/// \todo getPath() should be implemented! (also for BFS and DFS)
+
+#include <lemon/list_graph.h>
+#include <lemon/graph_utils.h>
+#include <lemon/invalid.h>
+#include <lemon/error.h>
+#include <lemon/maps.h>
+
+#include <limits>
+
+namespace lemon {
+
+ /// \brief Default OperationTraits for the FloydWarshall algorithm class.
+ ///
+ /// It defines all computational operations and constants which are
+ /// used in the Floyd-Warshall 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<Value>::has_infinity>
+ struct FloydWarshallDefaultOperationTraits {
+ /// \brief Gives back the zero value of the type.
+ static Value zero() {
+ return static_cast<Value>(0);
+ }
+ /// \brief Gives back the positive infinity value of the type.
+ static Value infinity() {
+ return std::numeric_limits<Value>::infinity();
+ }
+ /// \brief Gives back the sum of the given two elements.
+ static Value plus(const Value& left, const Value& right) {
+ return left + right;
+ }
+ /// \brief Gives back true only if the first value less than the second.
+ static bool less(const Value& left, const Value& right) {
+ return left < right;
+ }
+ };
+
+ template <typename Value>
+ struct FloydWarshallDefaultOperationTraits<Value, false> {
+ static Value zero() {
+ return static_cast<Value>(0);
+ }
+ static Value infinity() {
+ return std::numeric_limits<Value>::max();
+ }
+ static Value plus(const Value& left, const Value& right) {
+ if (left == infinity() || right == infinity()) return infinity();
+ return left + right;
+ }
+ static bool less(const Value& left, const Value& right) {
+ return left < right;
+ }
+ };
+
+ /// \brief Default traits class of FloydWarshall class.
+ ///
+ /// Default traits class of FloydWarshall class.
+ /// \param _Graph Graph type.
+ /// \param _LegthMap Type of length map.
+ template<class _Graph, class _LengthMap>
+ struct FloydWarshallDefaultTraits {
+ /// 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 belmann-ford algorithm.
+ ///
+ /// It defines the infinity type on the given Value type
+ /// and the used operation.
+ /// \see FloydWarshallDefaultOperationTraits
+ typedef FloydWarshallDefaultOperationTraits<Value> 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 be a matrix map with \c Graph::Edge value type.
+ ///
+ typedef NodeMatrixMap<Graph, typename Graph::Edge> 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 NodeMatrixMap<Graph, Value> 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 FloydWarshall algorithm class.
+ ///
+ /// \ingroup flowalgs
+ /// This class provides an efficient implementation of \c FloydWarshall
+ /// 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 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
+ /// FloydWarshall, it is only passed to \ref FloydWarshallDefaultTraits.
+ /// \param _LengthMap This read-only EdgeMap determines the lengths of the
+ /// edges. It is read once for each edge, so the map may involve in
+ /// relatively time consuming process to compute the edge length if
+ /// it is necessary. The default map type is \ref
+ /// concept::StaticGraph::EdgeMap "Graph::EdgeMap<int>". The value
+ /// of _LengthMap is not used directly by FloydWarshall, it is only passed
+ /// to \ref FloydWarshallDefaultTraits. \param _Traits Traits class to set
+ /// various data types used by the algorithm. The default traits
+ /// class is \ref FloydWarshallDefaultTraits
+ /// "FloydWarshallDefaultTraits<_Graph,_LengthMap>". See \ref
+ /// FloydWarshallDefaultTraits for the documentation of a FloydWarshall
+ /// traits class.
+ ///
+ /// \author Balazs Dezso
+
+
+ template <typename _Graph=ListGraph,
+ typename _LengthMap=typename _Graph::template EdgeMap<int>,
+ typename _Traits=FloydWarshallDefaultTraits<_Graph,_LengthMap> >
+ class FloydWarshall {
+ 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::FloydWarshall::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;
+
+ /// \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. The type of the PredMap
+ /// is a matrix map for Edges
+ typedef typename _Traits::PredMap PredMap;
+ /// \brief The type of the map that stores the dists of the nodes.
+ /// The type of the DistMap is a matrix map for Values
+ typedef typename _Traits::DistMap DistMap;
+ /// \brief The operation traits.
+ typedef typename _Traits::OperationTraits OperationTraits;
+ 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;
+
+ /// 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 :
+
+ /// \name Named template parameters
+
+ ///@{
+
+ template <class T>
+ struct DefPredMapTraits : public Traits {
+ typedef T PredMap;
+ static PredMap *createPredMap(const Graph& 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 <class T>
+ class DefPredMap
+ : public FloydWarshall< Graph, LengthMap, DefPredMapTraits<T> > {};
+
+ template <class T>
+ 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 <class T>
+ class DefDistMap
+ : public FloydWarshall< Graph, LengthMap, DefDistMapTraits<T> > {};
+
+ template <class T>
+ 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 PredMap type
+ template <class T>
+ class DefOperationTraits
+ : public FloydWarshall< Graph, LengthMap, DefOperationTraitsTraits<T> > {
+ };
+
+ ///@}
+
+ public:
+
+ /// \brief Constructor.
+ ///
+ /// \param _graph the graph the algorithm will run on.
+ /// \param _length the length map used by the algorithm.
+ FloydWarshall(const Graph& _graph, const LengthMap& _length) :
+ graph(&_graph), length(&_length),
+ _pred(0), local_pred(false),
+ _dist(0), local_dist(false) {}
+
+ ///Destructor.
+ ~FloydWarshall() {
+ if(local_pred) delete _pred;
+ if(local_dist) delete _dist;
+ }
+
+ /// \brief Sets the length map.
+ ///
+ /// Sets the length map.
+ /// \return \c (*this)
+ FloydWarshall &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)
+ FloydWarshall &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)
+ FloydWarshall &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,
+ /// Finally \ref start() will perform the actual path
+ /// computation.
+
+ ///@{
+
+ /// \brief Initializes the internal data structures.
+ ///
+ /// Initializes the internal data structures.
+ void init() {
+ create_maps();
+ for (NodeIt it(*graph); it != INVALID; ++it) {
+ for (NodeIt jt(*graph); jt != INVALID; ++jt) {
+ _pred->set(it, jt, INVALID);
+ _dist->set(it, jt, it == jt ?
+ OperationTraits::zero() : OperationTraits::infinity());
+ }
+ }
+ for (EdgeIt it(*graph); it != INVALID; ++it) {
+ Node source = graph->source(it);
+ Node target = graph->target(it);
+ if (OperationTraits::less((*length)[it], (*_dist)(source, target))) {
+ _dist->set(source, target, (*length)[it]);
+ _pred->set(source, target, it);
+ }
+ }
+ }
+
+ /// \brief Executes the algorithm.
+ ///
+ /// This method runs the %FloydWarshall algorithm in order to compute
+ /// the shortest path to each node pairs. The algorithm
+ /// computes
+ /// - The shortest path tree for each node.
+ /// - The distance between each node pairs.
+ void start() {
+ for (NodeIt kt(*graph); kt != INVALID; ++kt) {
+ for (NodeIt it(*graph); it != INVALID; ++it) {
+ for (NodeIt jt(*graph); jt != INVALID; ++jt) {
+ Value relaxed = OperationTraits::plus((*_dist)(it, kt),
+ (*_dist)(kt, jt));
+ if (OperationTraits::less(relaxed, (*_dist)(it, jt))) {
+ _dist->set(it, jt, relaxed);
+ _pred->set(it, jt, (*_pred)(kt, jt));
+ }
+ }
+ }
+ }
+ }
+
+ /// \brief Runs %FloydWarshall algorithm.
+ ///
+ /// This method runs the %FloydWarshall algorithm from a each node
+ /// in order to compute the shortest path to each node pairs.
+ /// The algorithm computes
+ /// - The shortest path tree for each node.
+ /// - The distance between each node pairs.
+ ///
+ /// \note d.run(s) is just a shortcut of the following code.
+ /// \code
+ /// d.init();
+ /// d.start();
+ /// \endcode
+ void run() {
+ init();
+ start();
+ }
+
+ ///@}
+
+ /// \name Query Functions
+ /// The result of the %FloydWarshall 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.
+ /// \todo Is it the right way to handle unreachable nodes?
+ /// \return Returns \c true if a path to \c t was actually copied to \c p,
+ /// \c false otherwise.
+ /// \sa DirPath
+ template <typename Path>
+ bool getPath(Path &p, Node source, Node target) {
+ if (connected(source, target)) {
+ p.clear();
+ typename Path::Builder b(target);
+ for(b.setStartNode(target); pred(source, target) != INVALID;
+ target = predNode(target)) {
+ b.pushFront(pred(source, target));
+ }
+ b.commit();
+ return true;
+ }
+ return false;
+ }
+
+ /// \brief The distance between two nodes.
+ ///
+ /// Returns the distance between two nodes.
+ /// \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 source, Node target) const {
+ return (*_dist)(source, target);
+ }
+
+ /// \brief Returns the 'previous edge' of the shortest path tree.
+ ///
+ /// For the node \c node it returns the 'previous edge' of the shortest
+ /// path tree to direction of the node \c root
+ /// i.e. it returns the last edge of a shortest path from the node \c root
+ /// to \c node. It is \ref INVALID if \c node is unreachable from the root
+ /// or if \c node=root. 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.
+ /// \todo predEdge could be a better name.
+ Edge pred(Node root, Node node) const {
+ return (*_pred)(root, node);
+ }
+
+ /// \brief Returns the 'previous node' of the shortest path tree.
+ ///
+ /// For a node \c node it returns the 'previous node' of the shortest path
+ /// tree to direction of the node \c root, i.e. it returns the last but
+ /// one node from a shortest path from the \c root to \c node. It is
+ /// INVALID if \c node is unreachable from the root or if \c node=root.
+ /// The shortest path tree used here is equal to the
+ /// shortest path tree used in \ref pred().
+ /// \pre \ref run() must be called before using this function.
+ Node predNode(Node root, Node node) const {
+ return (*_pred)(root, node) == INVALID ?
+ INVALID : graph->source((*_pred)(root, node));
+ }
+
+ /// \brief Returns a reference to the matrix node map of distances.
+ ///
+ /// Returns a reference to the matrix node map 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 matrix node map 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 connected(Node source, Node target) {
+ return (*_dist)(source, target) != OperationTraits::infinity();
+ }
+
+ ///@}
+ };
+
+} //END OF NAMESPACE LEMON
+
+#endif
+
Added: hugo/trunk/lemon/johnson.h
==============================================================================
--- (empty file)
+++ hugo/trunk/lemon/johnson.h Mon Oct 3 12:20:56 2005
@@ -0,0 +1,547 @@
+/* -*- C++ -*-
+ * lemon/johnson.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_JOHNSON_H
+#define LEMON_JOHNSON_H
+
+///\ingroup flowalgs
+/// \file
+/// \brief Johnson algorithm.
+///
+
+#include <lemon/list_graph.h>
+#include <lemon/graph_utils.h>
+#include <lemon/dfs.h>
+#include <lemon/dijkstra.h>
+#include <lemon/belmann_ford.h>
+#include <lemon/invalid.h>
+#include <lemon/error.h>
+#include <lemon/maps.h>
+
+#include <limits>
+
+namespace lemon {
+
+ /// \brief Default OperationTraits for the Johnson algorithm class.
+ ///
+ /// It defines all computational operations and constants which are
+ /// used in the Floyd-Warshall 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<Value>::has_infinity>
+ struct JohnsonDefaultOperationTraits {
+ /// \brief Gives back the zero value of the type.
+ static Value zero() {
+ return static_cast<Value>(0);
+ }
+ /// \brief Gives back the positive infinity value of the type.
+ static Value infinity() {
+ return std::numeric_limits<Value>::infinity();
+ }
+ /// \brief Gives back the sum of the given two elements.
+ static Value plus(const Value& left, const Value& right) {
+ return left + right;
+ }
+ /// \brief Gives back true only if the first value less than the second.
+ static bool less(const Value& left, const Value& right) {
+ return left < right;
+ }
+ };
+
+ template <typename Value>
+ struct JohnsonDefaultOperationTraits<Value, false> {
+ static Value zero() {
+ return static_cast<Value>(0);
+ }
+ static Value infinity() {
+ return std::numeric_limits<Value>::max();
+ }
+ static Value plus(const Value& left, const Value& right) {
+ if (left == infinity() || right == infinity()) return infinity();
+ return left + right;
+ }
+ static bool less(const Value& left, const Value& right) {
+ return left < right;
+ }
+ };
+
+ /// \brief Default traits class of Johnson class.
+ ///
+ /// Default traits class of Johnson class.
+ /// \param _Graph Graph type.
+ /// \param _LegthMap Type of length map.
+ template<class _Graph, class _LengthMap>
+ struct JohnsonDefaultTraits {
+ /// 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 belmann-ford algorithm.
+ ///
+ /// It defines the infinity type on the given Value type
+ /// and the used operation.
+ /// \see JohnsonDefaultOperationTraits
+ typedef JohnsonDefaultOperationTraits<Value> 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 be a matrix map with \c Graph::Edge value type.
+ ///
+ typedef NodeMatrixMap<Graph, typename Graph::Edge> 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 NodeMatrixMap<Graph, Value> 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 Johnson algorithm class.
+ ///
+ /// \ingroup flowalgs
+ /// This class provides an efficient implementation of \c Johnson
+ /// 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 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
+ /// Johnson, it is only passed to \ref JohnsonDefaultTraits.
+ /// \param _LengthMap This read-only EdgeMap determines the lengths of the
+ /// edges. It is read once for each edge, so the map may involve in
+ /// relatively time consuming process to compute the edge length if
+ /// it is necessary. The default map type is \ref
+ /// concept::StaticGraph::EdgeMap "Graph::EdgeMap<int>". The value
+ /// of _LengthMap is not used directly by Johnson, it is only passed
+ /// to \ref JohnsonDefaultTraits. \param _Traits Traits class to set
+ /// various data types used by the algorithm. The default traits
+ /// class is \ref JohnsonDefaultTraits
+ /// "JohnsonDefaultTraits<_Graph,_LengthMap>". See \ref
+ /// JohnsonDefaultTraits for the documentation of a Johnson traits
+ /// class.
+ ///
+ /// \author Balazs Dezso
+
+ template <typename _Graph=ListGraph,
+ typename _LengthMap=typename _Graph::template EdgeMap<int>,
+ typename _Traits=JohnsonDefaultTraits<_Graph,_LengthMap> >
+ class Johnson {
+ 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::Johnson::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;
+
+ /// \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. The type of the PredMap
+ /// is a matrix map for Edges
+ typedef typename _Traits::PredMap PredMap;
+ /// \brief The type of the map that stores the dists of the nodes.
+ /// The type of the DistMap is a matrix map for Values
+ typedef typename _Traits::DistMap DistMap;
+ /// \brief The operation traits.
+ typedef typename _Traits::OperationTraits OperationTraits;
+ 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;
+
+ /// 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 :
+
+ /// \name Named template parameters
+
+ ///@{
+
+ template <class T>
+ struct DefPredMapTraits : public Traits {
+ typedef T PredMap;
+ static PredMap *createPredMap(const Graph& 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 <class T>
+ class DefPredMap
+ : public Johnson< Graph, LengthMap, DefPredMapTraits<T> > {};
+
+ template <class T>
+ 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 <class T>
+ class DefDistMap
+ : public Johnson< Graph, LengthMap, DefDistMapTraits<T> > {};
+
+ template <class T>
+ 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 PredMap type
+ template <class T>
+ class DefOperationTraits
+ : public Johnson< Graph, LengthMap, DefOperationTraitsTraits<T> > {};
+
+ ///@}
+
+ public:
+
+ /// \brief Constructor.
+ ///
+ /// \param _graph the graph the algorithm will run on.
+ /// \param _length the length map used by the algorithm.
+ Johnson(const Graph& _graph, const LengthMap& _length) :
+ graph(&_graph), length(&_length),
+ _pred(0), local_pred(false),
+ _dist(0), local_dist(false) {}
+
+ ///Destructor.
+ ~Johnson() {
+ if(local_pred) delete _pred;
+ if(local_dist) delete _dist;
+ }
+
+ /// \brief Sets the length map.
+ ///
+ /// Sets the length map.
+ /// \return \c (*this)
+ Johnson &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)
+ Johnson &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)
+ Johnson &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,
+ /// Finally \ref start() will perform the actual path
+ /// computation.
+
+ ///@{
+
+ /// \brief Initializes the internal data structures.
+ ///
+ /// Initializes the internal data structures.
+ void init() {
+ create_maps();
+ }
+
+ /// \brief Executes the algorithm.
+ ///
+ /// This method runs the %Johnson algorithm in order to compute
+ /// the shortest path to each node pairs. The algorithm
+ /// computes
+ /// - The shortest path tree for each node.
+ /// - The distance between each node pairs.
+ void start() {
+ typename BelmannFord<Graph, LengthMap>::
+ template DefOperationTraits<OperationTraits>::
+ BelmannFord belmannford(*graph, *length);
+
+ belmannford.init();
+
+ typename Graph::template NodeMap<bool> initial(*graph, false);
+
+ {
+ Dfs<Graph> dfs(*graph);
+
+ dfs.init();
+ for (NodeIt it(*graph); it != INVALID; ++it) {
+ if (!dfs.reached(it)) {
+ dfs.addSource(it);
+ while (!dfs.emptyQueue()) {
+ Edge edge = dfs.processNextEdge();
+ initial.set(graph->target(edge), false);
+ }
+ initial.set(it, true);
+ }
+ }
+ for (NodeIt it(*graph); it != INVALID; ++it) {
+ if (initial[it]) {
+ belmannford.addSource(it);
+ }
+ }
+ }
+
+ belmannford.start();
+
+ for (NodeIt it(*graph); it != INVALID; ++it) {
+ typedef PotentialDifferenceMap<Graph,
+ typename BelmannFord<Graph, LengthMap>::DistMap> PotDiffMap;
+ PotDiffMap potdiff(*graph, belmannford.distMap());
+ typedef SubMap<LengthMap, PotDiffMap> ShiftLengthMap;
+ ShiftLengthMap shiftlen(*length, potdiff);
+ Dijkstra<Graph, ShiftLengthMap> dijkstra(*graph, shiftlen);
+ dijkstra.run(it);
+ for (NodeIt jt(*graph); jt != INVALID; ++jt) {
+ if (dijkstra.reached(jt)) {
+ _dist->set(it, jt, dijkstra.dist(jt) +
+ belmannford.dist(jt) - belmannford.dist(it));
+ _pred->set(it, jt, dijkstra.pred(jt));
+ } else {
+ _dist->set(it, jt, OperationTraits::infinity());
+ _pred->set(it, jt, INVALID);
+ }
+ }
+ }
+ }
+
+ /// \brief Runs %Johnson algorithm.
+ ///
+ /// This method runs the %Johnson algorithm from a each node
+ /// in order to compute the shortest path to each node pairs.
+ /// The algorithm computes
+ /// - The shortest path tree for each node.
+ /// - The distance between each node pairs.
+ ///
+ /// \note d.run(s) is just a shortcut of the following code.
+ /// \code
+ /// d.init();
+ /// d.start();
+ /// \endcode
+ void run() {
+ init();
+ start();
+ }
+
+ ///@}
+
+ /// \name Query Functions
+ /// The result of the %Johnson 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.
+ /// \todo Is it the right way to handle unreachable nodes?
+ /// \return Returns \c true if a path to \c t was actually copied to \c p,
+ /// \c false otherwise.
+ /// \sa DirPath
+ template <typename Path>
+ bool getPath(Path &p, Node source, Node target) {
+ if (connected(source, target)) {
+ p.clear();
+ typename Path::Builder b(target);
+ for(b.setStartNode(target); pred(source, target) != INVALID;
+ target = predNode(target)) {
+ b.pushFront(pred(source, target));
+ }
+ b.commit();
+ return true;
+ }
+ return false;
+ }
+
+ /// \brief The distance between two nodes.
+ ///
+ /// Returns the distance between two nodes.
+ /// \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 source, Node target) const {
+ return (*_dist)(source, target);
+ }
+
+ /// \brief Returns the 'previous edge' of the shortest path tree.
+ ///
+ /// For the node \c node it returns the 'previous edge' of the shortest
+ /// path tree to direction of the node \c root
+ /// i.e. it returns the last edge of a shortest path from the node \c root
+ /// to \c node. It is \ref INVALID if \c node is unreachable from the root
+ /// or if \c node=root. 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.
+ /// \todo predEdge could be a better name.
+ Edge pred(Node root, Node node) const {
+ return (*_pred)(root, node);
+ }
+
+ /// \brief Returns the 'previous node' of the shortest path tree.
+ ///
+ /// For a node \c node it returns the 'previous node' of the shortest path
+ /// tree to direction of the node \c root, i.e. it returns the last but
+ /// one node from a shortest path from the \c root to \c node. It is
+ /// INVALID if \c node is unreachable from the root or if \c node=root.
+ /// The shortest path tree used here is equal to the
+ /// shortest path tree used in \ref pred().
+ /// \pre \ref run() must be called before using this function.
+ Node predNode(Node root, Node node) const {
+ return (*_pred)(root, node) == INVALID ?
+ INVALID : graph->source((*_pred)(root, node));
+ }
+
+ /// \brief Returns a reference to the matrix node map of distances.
+ ///
+ /// Returns a reference to the matrix node map 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 matrix node map 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 connected(Node source, Node target) {
+ return (*_dist)(source, target) != OperationTraits::infinity();
+ }
+
+ ///@}
+ };
+
+} //END OF NAMESPACE LEMON
+
+#endif
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