lemon-1.3: comparison lemon/howard

equal deleted inserted replaced

-:4481e7a992f3
+:e1b123034949
 * express or implied, and with no claim as to its suitability for any
 * purpose.
 *
 */
-#ifndef LEMON_HOWARD_H
+#ifndef LEMON_HOWARD_MMC_H
-#define LEMON_HOWARD_H
+#define LEMON_HOWARD_MMC_H
 /// \ingroup min_mean_cycle
 ///
 /// \file
 /// \brief Howard's algorithm for finding a minimum mean cycle.
 #include <lemon/tolerance.h>
 #include <lemon/connectivity.h>
 namespace lemon {
-/// \brief Default traits class of Howard class.
+/// \brief Default traits class of HowardMmc class.
 ///
-/// Default traits class of Howard class.
+/// Default traits class of HowardMmc class.
 /// \tparam GR The type of the digraph.
-/// \tparam LEN The type of the length map.
+/// \tparam CM The type of the cost map.
 /// It must conform to the \ref concepts::ReadMap "ReadMap" concept.
 #ifdef DOXYGEN
-template <typename GR, typename LEN>
+template <typename GR, typename CM>
 #else
-template <typename GR, typename LEN,
+template <typename GR, typename CM,
-bool integer = std::numeric_limits<typename LEN::Value>::is_integer>
+bool integer = std::numeric_limits<typename CM::Value>::is_integer>
 #endif
-struct HowardDefaultTraits
+struct HowardMmcDefaultTraits
 {
 /// The type of the digraph
 typedef GR Digraph;
-/// The type of the length map
+/// The type of the cost map
-typedef LEN LengthMap;
+typedef CM CostMap;
-/// The type of the arc lengths
+/// The type of the arc costs
-typedef typename LengthMap::Value Value;
+typedef typename CostMap::Value Cost;
-/// \brief The large value type used for internal computations
+/// \brief The large cost type used for internal computations
 ///
-/// The large value type used for internal computations.
+/// The large cost type used for internal computations.
-/// It is \c long \c long if the \c Value type is integer,
+/// It is \c long \c long if the \c Cost type is integer,
 /// otherwise it is \c double.
-/// \c Value must be convertible to \c LargeValue.
+/// \c Cost must be convertible to \c LargeCost.
-typedef double LargeValue;
+typedef double LargeCost;
 /// The tolerance type used for internal computations
-typedef lemon::Tolerance<LargeValue> Tolerance;
+typedef lemon::Tolerance<LargeCost> Tolerance;
 /// \brief The path type of the found cycles
 ///
 /// The path type of the found cycles.
 /// It must conform to the \ref lemon::concepts::Path "Path" concept
 /// and it must have an \c addBack() function.
 typedef lemon::Path<Digraph> Path;
 };
-// Default traits class for integer value types
+// Default traits class for integer cost types
-template <typename GR, typename LEN>
+template <typename GR, typename CM>
-struct HowardDefaultTraits<GR, LEN, true>
+struct HowardMmcDefaultTraits<GR, CM, true>
 {
 typedef GR Digraph;
-typedef LEN LengthMap;
+typedef CM CostMap;
-typedef typename LengthMap::Value Value;
+typedef typename CostMap::Value Cost;
 #ifdef LEMON_HAVE_LONG_LONG
-typedef long long LargeValue;
+typedef long long LargeCost;
 #else
-typedef long LargeValue;
+typedef long LargeCost;
 #endif
-typedef lemon::Tolerance<LargeValue> Tolerance;
+typedef lemon::Tolerance<LargeCost> Tolerance;
 typedef lemon::Path<Digraph> Path;
 };
 /// \addtogroup min_mean_cycle
 /// \brief Implementation of Howard's algorithm for finding a minimum
 /// mean cycle.
 ///
 /// This class implements Howard's policy iteration algorithm for finding
-/// a directed cycle of minimum mean length (cost) in a digraph
+/// a directed cycle of minimum mean cost in a digraph
 /// \ref amo93networkflows, \ref dasdan98minmeancycle.
 /// This class provides the most efficient algorithm for the
 /// minimum mean cycle problem, though the best known theoretical
 /// bound on its running time is exponential.
 ///
 /// \tparam GR The type of the digraph the algorithm runs on.
-/// \tparam LEN The type of the length map. The default
+/// \tparam CM The type of the cost map. The default
 /// map type is \ref concepts::Digraph::ArcMap "GR::ArcMap<int>".
 /// \tparam TR The traits class that defines various types used by the
-/// algorithm. By default, it is \ref HowardDefaultTraits
+/// algorithm. By default, it is \ref HowardMmcDefaultTraits
-/// "HowardDefaultTraits<GR, LEN>".
+/// "HowardMmcDefaultTraits<GR, CM>".
 /// In most cases, this parameter should not be set directly,
 /// consider to use the named template parameters instead.
 #ifdef DOXYGEN
-template <typename GR, typename LEN, typename TR>
+template <typename GR, typename CM, typename TR>
 #else
 template < typename GR,
-typename LEN = typename GR::template ArcMap<int>,
+typename CM = typename GR::template ArcMap<int>,
-typename TR = HowardDefaultTraits<GR, LEN> >
+typename TR = HowardMmcDefaultTraits<GR, CM> >
 #endif
-class Howard
+class HowardMmc
 {
 public:
 /// The type of the digraph
 typedef typename TR::Digraph Digraph;
-/// The type of the length map
+/// The type of the cost map
-typedef typename TR::LengthMap LengthMap;
+typedef typename TR::CostMap CostMap;
-/// The type of the arc lengths
+/// The type of the arc costs
-typedef typename TR::Value Value;
+typedef typename TR::Cost Cost;
-/// \brief The large value type
+/// \brief The large cost type
 ///
-/// The large value type used for internal computations.
+/// The large cost type used for internal computations.
-/// By default, it is \c long \c long if the \c Value type is integer,
+/// By default, it is \c long \c long if the \c Cost type is integer,
 /// otherwise it is \c double.
-typedef typename TR::LargeValue LargeValue;
+typedef typename TR::LargeCost LargeCost;
 /// The tolerance type
 typedef typename TR::Tolerance Tolerance;
 /// \brief The path type of the found cycles
 ///
 /// The path type of the found cycles.
-/// Using the \ref HowardDefaultTraits "default traits class",
+/// Using the \ref HowardMmcDefaultTraits "default traits class",
 /// it is \ref lemon::Path "Path<Digraph>".
 typedef typename TR::Path Path;
-/// The \ref HowardDefaultTraits "traits class" of the algorithm
+/// The \ref HowardMmcDefaultTraits "traits class" of the algorithm
 typedef TR Traits;
 private:
 TEMPLATE_DIGRAPH_TYPEDEFS(Digraph);
 // The digraph the algorithm runs on
 const Digraph &_gr;
-// The length of the arcs
+// The cost of the arcs
-const LengthMap &_length;
+const CostMap &_cost;
 // Data for the found cycles
 bool _curr_found, _best_found;
-LargeValue _curr_length, _best_length;
+LargeCost _curr_cost, _best_cost;
 int _curr_size, _best_size;
 Node _curr_node, _best_node;
 Path *_cycle_path;
 bool _local_path;
 // Internal data used by the algorithm
 typename Digraph::template NodeMap<Arc> _policy;
 typename Digraph::template NodeMap<bool> _reached;
 typename Digraph::template NodeMap<int> _level;
-typename Digraph::template NodeMap<LargeValue> _dist;
+typename Digraph::template NodeMap<LargeCost> _dist;
 // Data for storing the strongly connected components
 int _comp_num;
 typename Digraph::template NodeMap<int> _comp;
 std::vector<std::vector<Node> > _comp_nodes;
 int _qfront, _qback;
 Tolerance _tolerance;
 // Infinite constant
-const LargeValue INF;
+const LargeCost INF;
 public:
 /// \name Named Template Parameters
 /// @{
 template <typename T>
-struct SetLargeValueTraits : public Traits {
+struct SetLargeCostTraits : public Traits {
-typedef T LargeValue;
+typedef T LargeCost;
 typedef lemon::Tolerance<T> Tolerance;
 };
 /// \brief \ref named-templ-param "Named parameter" for setting
-/// \c LargeValue type.
+/// \c LargeCost type.
 ///
-/// \ref named-templ-param "Named parameter" for setting \c LargeValue
+/// \ref named-templ-param "Named parameter" for setting \c LargeCost
 /// type. It is used for internal computations in the algorithm.
 template <typename T>
-struct SetLargeValue
+struct SetLargeCost
-: public Howard<GR, LEN, SetLargeValueTraits<T> > {
+: public HowardMmc<GR, CM, SetLargeCostTraits<T> > {
-typedef Howard<GR, LEN, SetLargeValueTraits<T> > Create;
+typedef HowardMmc<GR, CM, SetLargeCostTraits<T> > Create;
 };
 template <typename T>
 struct SetPathTraits : public Traits {
 typedef T Path;
 /// type of the found cycles.
 /// It must conform to the \ref lemon::concepts::Path "Path" concept
 /// and it must have an \c addBack() function.
 template <typename T>
 struct SetPath
-: public Howard<GR, LEN, SetPathTraits<T> > {
+: public HowardMmc<GR, CM, SetPathTraits<T> > {
-typedef Howard<GR, LEN, SetPathTraits<T> > Create;
+typedef HowardMmc<GR, CM, SetPathTraits<T> > Create;
 };
 /// @}
 protected:
-Howard() {}
+HowardMmc() {}
 public:
 /// \brief Constructor.
 ///
 /// The constructor of the class.
 ///
 /// \param digraph The digraph the algorithm runs on.
-/// \param length The lengths (costs) of the arcs.
+/// \param cost The costs of the arcs.
-Howard( const Digraph &digraph,
+HowardMmc( const Digraph &digraph,
-const LengthMap &length ) :
+const CostMap &cost ) :
-_gr(digraph), _length(length), _best_found(false),
+_gr(digraph), _cost(cost), _best_found(false),
-_best_length(0), _best_size(1), _cycle_path(NULL), _local_path(false),
+_best_cost(0), _best_size(1), _cycle_path(NULL), _local_path(false),
 _policy(digraph), _reached(digraph), _level(digraph), _dist(digraph),
 _comp(digraph), _in_arcs(digraph),
-INF(std::numeric_limits<LargeValue>::has_infinity ?
+INF(std::numeric_limits<LargeCost>::has_infinity ?
-std::numeric_limits<LargeValue>::infinity() :
+std::numeric_limits<LargeCost>::infinity() :
-std::numeric_limits<LargeValue>::max())
+std::numeric_limits<LargeCost>::max())
 {}
 /// Destructor.
-~Howard() {
+~HowardMmc() {
 if (_local_path) delete _cycle_path;
 }
 /// \brief Set the path structure for storing the found cycle.
 ///
 /// This function sets an external path structure for storing the
 /// found cycle.
 ///
 /// If you don't call this function before calling \ref run() or
-/// \ref findMinMean(), it will allocate a local \ref Path "path"
+/// \ref findCycleMean(), it will allocate a local \ref Path "path"
 /// structure. The destuctor deallocates this automatically
 /// allocated object, of course.
 ///
 /// \note The algorithm calls only the \ref lemon::Path::addBack()
 /// "addBack()" function of the given path structure.
 ///
 /// \return <tt>(*this)</tt>
-Howard& cycle(Path &path) {
+HowardMmc& cycle(Path &path) {
 if (_local_path) {
 delete _cycle_path;
 _local_path = false;
 }
 _cycle_path = &path;
 /// \brief Set the tolerance used by the algorithm.
 ///
 /// This function sets the tolerance object used by the algorithm.
 ///
 /// \return <tt>(*this)</tt>
-Howard& tolerance(const Tolerance& tolerance) {
+HowardMmc& tolerance(const Tolerance& tolerance) {
 _tolerance = tolerance;
 return *this;
 }
 /// \brief Return a const reference to the tolerance.
 }
 /// \name Execution control
 /// The simplest way to execute the algorithm is to call the \ref run()
 /// function.\n
-/// If you only need the minimum mean length, you may call
+/// If you only need the minimum mean cost, you may call
-/// \ref findMinMean().
+/// \ref findCycleMean().
 /// @{
 /// \brief Run the algorithm.
 ///
 /// This function runs the algorithm.
 /// It can be called more than once (e.g. if the underlying digraph
-/// and/or the arc lengths have been modified).
+/// and/or the arc costs have been modified).
 ///
 /// \return \c true if a directed cycle exists in the digraph.
 ///
 /// \note <tt>mmc.run()</tt> is just a shortcut of the following code.
 /// \code
-///   return mmc.findMinMean() && mmc.findCycle();
+///   return mmc.findCycleMean() && mmc.findCycle();
 /// \endcode
 bool run() {
-return findMinMean() && findCycle();
+return findCycleMean() && findCycle();
 }
 /// \brief Find the minimum cycle mean.
 ///
-/// This function finds the minimum mean length of the directed
+/// This function finds the minimum mean cost of the directed
 /// cycles in the digraph.
 ///
 /// \return \c true if a directed cycle exists in the digraph.
-bool findMinMean() {
+bool findCycleMean() {
 // Initialize and find strongly connected components
 init();
 findComponents();
 // Find the minimum cycle mean in the components
 findPolicyCycle();
 if (!computeNodeDistances()) break;
 }
 // Update the best cycle (global minimum mean cycle)
 if ( _curr_found && (!_best_found ||
-_curr_length * _best_size < _best_length * _curr_size) ) {
+_curr_cost * _best_size < _best_cost * _curr_size) ) {
 _best_found = true;
-_best_length = _curr_length;
+_best_cost = _curr_cost;
 _best_size = _curr_size;
 _best_node = _curr_node;
 }
 }
 return _best_found;
 }
 /// \brief Find a minimum mean directed cycle.
 ///
-/// This function finds a directed cycle of minimum mean length
+/// This function finds a directed cycle of minimum mean cost
-/// in the digraph using the data computed by findMinMean().
+/// in the digraph using the data computed by findCycleMean().
 ///
 /// \return \c true if a directed cycle exists in the digraph.
 ///
-/// \pre \ref findMinMean() must be called before using this function.
+/// \pre \ref findCycleMean() must be called before using this function.
 bool findCycle() {
 if (!_best_found) return false;
 _cycle_path->addBack(_policy[_best_node]);
 for ( Node v = _best_node;
 (v = _gr.target(_policy[v])) != _best_node; ) {
 /// functions.\n
 /// The algorithm should be executed before using them.
 /// @{
-/// \brief Return the total length of the found cycle.
+/// \brief Return the total cost of the found cycle.
 ///
-/// This function returns the total length of the found cycle.
+/// This function returns the total cost of the found cycle.
 ///
-/// \pre \ref run() or \ref findMinMean() must be called before
+/// \pre \ref run() or \ref findCycleMean() must be called before
 /// using this function.
-Value cycleLength() const {
+Cost cycleCost() const {
-return static_cast<Value>(_best_length);
+return static_cast<Cost>(_best_cost);
 }
 /// \brief Return the number of arcs on the found cycle.
 ///
 /// This function returns the number of arcs on the found cycle.
 ///
-/// \pre \ref run() or \ref findMinMean() must be called before
+/// \pre \ref run() or \ref findCycleMean() must be called before
 /// using this function.
-int cycleArcNum() const {
+int cycleSize() const {
 return _best_size;
 }
-/// \brief Return the mean length of the found cycle.
+/// \brief Return the mean cost of the found cycle.
 ///
-/// This function returns the mean length of the found cycle.
+/// This function returns the mean cost of the found cycle.
 ///
 /// \note <tt>alg.cycleMean()</tt> is just a shortcut of the
 /// following code.
 /// \code
-///   return static_cast<double>(alg.cycleLength()) / alg.cycleArcNum();
+///   return static_cast<double>(alg.cycleCost()) / alg.cycleSize();
 /// \endcode
 ///
-/// \pre \ref run() or \ref findMinMean() must be called before
+/// \pre \ref run() or \ref findCycleMean() must be called before
 /// using this function.
 double cycleMean() const {
-return static_cast<double>(_best_length) / _best_size;
+return static_cast<double>(_best_cost) / _best_size;
 }
 /// \brief Return the found cycle.
 ///
 /// This function returns a const reference to the path structure
 _local_path = true;
 _cycle_path = new Path;
 }
 _queue.resize(countNodes(_gr));
 _best_found = false;
-_best_length = 0;
+_best_cost = 0;
 _best_size = 1;
 _cycle_path->clear();
 }
 // Find strongly connected components and initialize _comp_nodes
 for (int i = 0; i < int(_nodes->size()); ++i) {
 v = (*_nodes)[i];
 for (int j = 0; j < int(_in_arcs[v].size()); ++j) {
 e = _in_arcs[v][j];
 u = _gr.source(e);
-if (_length[e] < _dist[u]) {
+if (_cost[e] < _dist[u]) {
-_dist[u] = _length[e];
+_dist[u] = _cost[e];
 _policy[u] = e;
 }
 }
 }
 return true;
 // Find the minimum mean cycle in the policy graph
 void findPolicyCycle() {
 for (int i = 0; i < int(_nodes->size()); ++i) {
 _level[(*_nodes)[i]] = -1;
 }
-LargeValue clength;
+LargeCost ccost;
 int csize;
 Node u, v;
 _curr_found = false;
 for (int i = 0; i < int(_nodes->size()); ++i) {
 u = (*_nodes)[i];
 for (; _level[u] < 0; u = _gr.target(_policy[u])) {
 _level[u] = i;
 }
 if (_level[u] == i) {
 // A cycle is found
-clength = _length[_policy[u]];
+ccost = _cost[_policy[u]];
 csize = 1;
 for (v = u; (v = _gr.target(_policy[v])) != u; ) {
-clength += _length[_policy[v]];
+ccost += _cost[_policy[v]];
 ++csize;
 }
 if ( !_curr_found ||
-(clength * _curr_size < _curr_length * csize) ) {
+(ccost * _curr_size < _curr_cost * csize) ) {
 _curr_found = true;
-_curr_length = clength;
+_curr_cost = ccost;
 _curr_size = csize;
 _curr_node = u;
 }
 }
 }
 for (int j = 0; j < int(_in_arcs[v].size()); ++j) {
 e = _in_arcs[v][j];
 u = _gr.source(e);
 if (_policy[u] == e && !_reached[u]) {
 _reached[u] = true;
-_dist[u] = _dist[v] + _length[e] * _curr_size - _curr_length;
+_dist[u] = _dist[v] + _cost[e] * _curr_size - _curr_cost;
 _queue[++_qback] = u;
 }
 }
 }
 e = _in_arcs[v][j];
 u = _gr.source(e);
 if (!_reached[u]) {
 _reached[u] = true;
 _policy[u] = e;
-_dist[u] = _dist[v] + _length[e] * _curr_size - _curr_length;
+_dist[u] = _dist[v] + _cost[e] * _curr_size - _curr_cost;
 _queue[++_qback] = u;
 }
 }
 }
 for (int i = 0; i < int(_nodes->size()); ++i) {
 v = (*_nodes)[i];
 for (int j = 0; j < int(_in_arcs[v].size()); ++j) {
 e = _in_arcs[v][j];
 u = _gr.source(e);
-LargeValue delta = _dist[v] + _length[e] * _curr_size - _curr_length;
+LargeCost delta = _dist[v] + _cost[e] * _curr_size - _curr_cost;
 if (_tolerance.less(delta, _dist[u])) {
 _dist[u] = delta;
 _policy[u] = e;
 improved = true;
 }
 }
 }
 return improved;
 }
-}; //class Howard
+}; //class HowardMmc
 ///@}
 } //namespace lemon
-#endif //LEMON_HOWARD_H
+#endif //LEMON_HOWARD_MMC_H

changeset 866	2d9c6566a604
parent 863	a93f1a27d831
child 877	141f9c0db4a3