Changeset 2583:7216b6a52ab9 in lemon-0.x for lemon/min_mean_cycle.h

Timestamp:

02/28/08 03:57:36 (16 years ago)

Author:

Peter Kovacs

Branch:

default

Phase:

public

Convert:

svn:c9d7d8f5-90d6-0310-b91f-818b3a526b0e/lemon/trunk@3465

Message:

Small fixes and doc improvements in MinMeanCycle?.

File:

• lemon/min_mean_cycle.h (modified) (14 diffs)

lemon/min_mean_cycle.h

@@ -27 +27 @@
 #include <vector>
 #include <lemon/graph_utils.h>
-#include <lemon/topology.h>
 #include <lemon/path.h>
 #include <lemon/tolerance.h>
+#include <lemon/topology.h>
 
 namespace lemon {
@@ -42 +42 @@
   /// minimum mean directed cycle.
   ///
-  /// \param Graph The directed graph type the algorithm runs on.
-  /// \param LengthMap The type of the length (cost) map.
+  /// \tparam Graph The directed graph type the algorithm runs on.
+  /// \tparam LengthMap The type of the length (cost) map.
   ///
   /// \warning \c LengthMap::Value must be convertible to \c double.
@@ -58 +58 @@
     typedef Path<Graph> Path;
 
-  protected:
+  private:
+
+    // The directed graph the algorithm runs on
+    const Graph &_graph;
+    // The length of the edges
+    const LengthMap &_length;
+
+    // The total length of the found cycle
+    Length _cycle_length;
+    // The number of edges on the found cycle
+    int _cycle_size;
+    // The found cycle
+    Path *_cycle_path;
+
+    bool _local_path;
+    bool _cycle_found;
+    Node _cycle_node;
 
     typename Graph::template NodeMap<bool> _reached;
     typename Graph::template NodeMap<double> _dist;
     typename Graph::template NodeMap<Edge> _policy;
-
-    /// The directed graph the algorithm runs on.
-    const Graph &_graph;
-    /// The length of the edges.
-    const LengthMap &_length;
-
-    /// The total length of the found cycle.
-    Length _cycle_length;
-    /// The number of edges on the found cycle.
-    int _cycle_size;
-    /// The found cycle.
-    Path *_cycle_path;
-
-    bool _local_path;
-    bool _cycle_found;
-    Node _cycle_node;
 
     typename Graph::template NodeMap<int> _component;
@@ -97 +97 @@
     MinMeanCycle( const Graph &graph,
                   const LengthMap &length ) :
-      _graph(graph), _length(length), _dist(graph), _reached(graph),
-      _policy(graph), _component(graph), _cycle_length(0),
-      _cycle_size(-1), _cycle_path(NULL), _local_path(false)
-    { }
+      _graph(graph), _length(length), _cycle_length(0), _cycle_size(-1),
+      _cycle_path(NULL), _local_path(false), _reached(graph),
+      _dist(graph), _policy(graph), _component(graph)
+    {}
 
     /// The destructor of the class.
@@ -107 +107 @@
     }
 
-  protected:
+    /// \brief Sets the \ref Path "path" structure for storing the found
+    /// cycle.
+    ///
+    /// Sets an external \ref Path "path" structure for storing the
+    /// found cycle.
+    ///
+    /// If you don't call this function before calling \ref run() or
+    /// \ref init(), it will allocate a local \ref Path "path"
+    /// structure.
+    /// The destuctor deallocates this automatically allocated map,
+    /// of course.
+    ///
+    /// \note The algorithm calls only the \ref lemon::Path::addBack()
+    /// "addBack()" function of the given \ref Path "path" structure.
+    ///
+    /// \return <tt>(*this)</tt>
+    ///
+    /// \sa cycle()
+    MinMeanCycle& cyclePath(Path &path) {
+      if (_local_path) {
+        delete _cycle_path;
+        _local_path = false;
+      }
+      _cycle_path = &path;
+      return *this;
+    }
+
+    /// \name Execution control
+    /// The simplest way to execute the algorithm is to call run().
+    /// \n
+    /// If you only need the minimum mean value, you may call init()
+    /// and findMinMean().
+    /// \n
+    /// If you would like to run the algorithm again (e.g. the
+    /// underlaying graph and/or the edge costs were modified), you may
+    /// not create a new instance of the class, rather call reset(),
+    /// findMinMean(), and findCycle() instead.
+
+    /// @{
+
+    /// \brief Runs the algorithm.
+    ///
+    /// Runs the algorithm.
+    ///
+    /// \return Returns \c true if a directed cycle exists in the graph.
+    ///
+    /// \note Apart from the return value, <tt>mmc.run()</tt> is just a
+    /// shortcut of the following code.
+    /// \code
+    ///   mmc.init();
+    ///   mmc.findMinMean();
+    ///   mmc.findCycle();
+    /// \endcode
+    bool run() {
+      init();
+      return findMinMean() && findCycle();
+    }
+
+    /// \brief Initializes the internal data structures.
+    ///
+    /// Initializes the internal data structures.
+    ///
+    /// \sa reset()
+    void init() {
+      _tolerance.epsilon(1e-6);
+      if (!_cycle_path) {
+        _local_path = true;
+        _cycle_path = new Path;
+      }
+      _cycle_found = false;
+      _component_num = stronglyConnectedComponents(_graph, _component);
+    }
+
+    /// \brief Resets the internal data structures.
+    ///
+    /// Resets the internal data structures so that \ref findMinMean()
+    /// and \ref findCycle() can be called again (e.g. when the
+    /// underlaying graph has been modified).
+    ///
+    /// \sa init()
+    void reset() {
+      if (_cycle_path) _cycle_path->clear();
+      _cycle_found = false;
+      _component_num = stronglyConnectedComponents(_graph, _component);
+    }
+
+    /// \brief Finds the minimum cycle mean length in the graph.
+    ///
+    /// Computes all the required data and finds the minimum cycle mean
+    /// length in the graph.
+    ///
+    /// \return Returns \c true if a directed cycle exists in the graph.
+    ///
+    /// \pre \ref init() must be called before using this function.
+    bool findMinMean() {
+      // Finding the minimum mean cycle in the components
+      for (int comp = 0; comp < _component_num; ++comp) {
+        if (!initCurrentComponent(comp)) continue;
+        while (true) {
+          if (!findPolicyCycles()) break;
+          contractPolicyGraph(comp);
+          if (!computeNodeDistances(comp)) break;
+        }
+      }
+      return _cycle_found;
+    }
+
+    /// \brief Finds a critical (minimum mean) directed cycle.
+    ///
+    /// Finds a critical (minimum mean) directed cycle using the data
+    /// computed in the \ref findMinMean() function.
+    ///
+    /// \return Returns \c true if a directed cycle exists in the graph.
+    ///
+    /// \pre \ref init() and \ref findMinMean() must be called before
+    /// using this function.
+    bool findCycle() {
+      if (!_cycle_found) return false;
+      _cycle_path->addBack(_policy[_cycle_node]);
+      for ( Node v = _cycle_node;
+            (v = _graph.target(_policy[v])) != _cycle_node; ) {
+        _cycle_path->addBack(_policy[v]);
+      }
+      return true;
+    }
+    
+    /// @}
+
+    /// \name Query Functions
+    /// The result of the algorithm can be obtained using these
+    /// functions.
+    /// \n run() must be called before using them.
+
+    /// @{
+    
+    /// \brief Returns the total length of the found cycle.
+    ///
+    /// Returns the total length of the found cycle.
+    ///
+    /// \pre \ref run() or \ref findMinMean() must be called before
+    /// using this function.
+    Length cycleLength() const {
+      return _cycle_length;
+    }
+
+    /// \brief Returns the number of edges on the found cycle.
+    ///
+    /// Returns the number of edges on the found cycle.
+    ///
+    /// \pre \ref run() or \ref findMinMean() must be called before
+    /// using this function.
+    int cycleEdgeNum() const {
+      return _cycle_size;
+    }
+
+    /// \brief Returns the mean length of the found cycle.
+    ///
+    /// Returns the mean length of the found cycle.
+    ///
+    /// \pre \ref run() or \ref findMinMean() must be called before
+    /// using this function.
+    ///
+    /// \note <tt>mmc.cycleMean()</tt> is just a shortcut of the
+    /// following code.
+    /// \code
+    ///   return double(mmc.cycleLength()) / mmc.cycleEdgeNum();
+    /// \endcode
+    double cycleMean() const {
+      return double(_cycle_length) / _cycle_size;
+    }
+
+    /// \brief Returns a const reference to the \ref Path "path"
+    /// structure storing the found cycle.
+    ///
+    /// Returns a const reference to the \ref Path "path"
+    /// structure storing the found cycle.
+    ///
+    /// \pre \ref run() or \ref findCycle() must be called before using
+    /// this function.
+    ///
+    /// \sa cyclePath()
+    const Path& cycle() const {
+      return *_cycle_path;
+    }
+    
+    ///@}
+    
+  private:
 
     // Initializes the internal data structures for the current strongly
@@ -128 +315 @@
       }
       // Initializing _reached, _dist, _policy maps
-      for (int i = 0; i < _nodes.size(); ++i) {
+      for (int i = 0; i < int(_nodes.size()); ++i) {
         _reached[_nodes[i]] = false;
         _policy[_nodes[i]] = INVALID;
       }
       Node u; Edge e;
-      for (int j = 0; j < _edges.size(); ++j) {
+      for (int j = 0; j < int(_edges.size()); ++j) {
         e = _edges[j];
         u = _graph.source(e);
@@ -149 +336 @@
     // _cycle_length, _cycle_size, _cycle_node to represent the minimum
     // mean cycle in the policy graph.
-    bool findPolicyCycles(int comp) {
+    bool findPolicyCycles() {
       typename Graph::template NodeMap<int> level(_graph, -1);
-      _cycle_found = false;
+      bool curr_cycle_found = false;
       Length clength;
       int csize;
@@ -157 +344 @@
       Node u, v;
       // Searching for cycles
-      for (int i = 0; i < _nodes.size(); ++i) {
+      for (int i = 0; i < int(_nodes.size()); ++i) {
         if (level[_nodes[i]] < 0) {
           u = _nodes[i];
@@ -165 +352 @@
           if (level[u] == path_cnt) {
             // A cycle is found
+            curr_cycle_found = true;
             clength = _length[_policy[u]];
             csize = 1;
@@ -182 +370 @@
         }
       }
-      return _cycle_found;
+      return curr_cycle_found;
     }
 
@@ -208 +396 @@
       // reverse BFS search
       queue.clear();
-      for (int i = 0; i < _nodes.size(); ++i)
+      for (int i = 0; i < int(_nodes.size()); ++i)
         if (found[_nodes[i]]) queue.push_back(_nodes[i]);
       int found_cnt = queue.size();
-      while (found_cnt < _nodes.size() && !queue.empty()) {
+      while (found_cnt < int(_nodes.size()) && !queue.empty()) {
         v = queue.front(); queue.pop_front();
         for (InEdgeIt e(_graph, v); e != INVALID; ++e) {
@@ -229 +417 @@
     bool computeNodeDistances(int comp) {
       // Computing node distances using reverse BFS search
-      double cycle_mean = (double)_cycle_length / _cycle_size;
+      double cycle_mean = double(_cycle_length) / _cycle_size;
       typename Graph::template NodeMap<int> found(_graph, false);
       std::deque<Node> queue;
       queue.push_back(_cycle_node);
       found[_cycle_node] = true;
+      _dist[_cycle_node] = 0;
       Node u, v;
       while (!queue.empty()) {
@@ -248 +437 @@
       // Improving node distances
       bool improved = false;
-      for (int j = 0; j < _edges.size(); ++j) {
+      for (int j = 0; j < int(_edges.size()); ++j) {
         Edge e = _edges[j];
         u = _graph.source(e); v = _graph.target(e);
@@ -261 +450 @@
     }
 
-  public:
-
-    /// \brief Runs the algorithm.
-    ///
-    /// Runs the algorithm.
-    ///
-    /// \return Returns \c true if a directed cycle exists in the graph.
-    ///
-    /// \note Apart from the return value, <tt>mmc.run()</tt> is just a
-    /// shortcut of the following code.
-    /// \code
-    ///   mmc.init();
-    ///   mmc.findMinMean();
-    ///   mmc.findCycle();
-    /// \endcode
-    bool run() {
-      init();
-      return findMinMean() && findCycle();
-    }
-
-    /// \brief Initializes the internal data structures.
-    ///
-    /// Initializes the internal data structures.
-    ///
-    /// \sa reset()
-    void init() {
-      _tolerance.epsilon(1e-8);
-      if (!_cycle_path) {
-        _local_path = true;
-        _cycle_path = new Path;
-      }
-      _cycle_found = false;
-      _component_num = stronglyConnectedComponents(_graph, _component);
-    }
-
-    /// \brief Resets the internal data structures.
-    ///
-    /// Resets the internal data structures so that \ref findMinMean()
-    /// and \ref findCycle() can be called again (e.g. when the
-    /// underlaying graph has been modified).
-    ///
-    /// \sa init()
-    void reset() {
-      if (_cycle_path) _cycle_path->clear();
-      _cycle_found = false;
-      _component_num = stronglyConnectedComponents(_graph, _component);
-    }
-
-    /// \brief Finds the minimum cycle mean length in the graph.
-    ///
-    /// Computes all the required data and finds the minimum cycle mean
-    /// length in the graph.
-    ///
-    /// \return Returns \c true if a directed cycle exists in the graph.
-    ///
-    /// \pre \ref init() must be called before using this function.
-    bool findMinMean() {
-      // Finding the minimum mean cycle in the components
-      for (int comp = 0; comp < _component_num; ++comp) {
-        if (!initCurrentComponent(comp)) continue;
-        while (true) {
-          if (!findPolicyCycles(comp)) return false;
-          contractPolicyGraph(comp);
-          if (!computeNodeDistances(comp)) return true;
-        }
-      }
-    }
-
-    /// \brief Finds a critical (minimum mean) directed cycle.
-    ///
-    /// Finds a critical (minimum mean) directed cycle using the data
-    /// computed in the \ref findMinMean() function.
-    ///
-    /// \return Returns \c true if a directed cycle exists in the graph.
-    ///
-    /// \pre \ref init() and \ref findMinMean() must be called before
-    /// using this function.
-    bool findCycle() {
-      if (!_cycle_found) return false;
-      _cycle_path->addBack(_policy[_cycle_node]);
-      for ( Node v = _cycle_node;
-            (v = _graph.target(_policy[v])) != _cycle_node; ) {
-        _cycle_path->addBack(_policy[v]);
-      }
-      return true;
-    }
-
-    /// \brief Returns the total length of the found cycle.
-    ///
-    /// Returns the total length of the found cycle.
-    ///
-    /// \pre \ref run() or \ref findMinMean() must be called before
-    /// using this function.
-    Length cycleLength() const {
-      return _cycle_length;
-    }
-
-    /// \brief Returns the number of edges on the found cycle.
-    ///
-    /// Returns the number of edges on the found cycle.
-    ///
-    /// \pre \ref run() or \ref findMinMean() must be called before
-    /// using this function.
-    int cycleEdgeNum() const {
-      return _cycle_size;
-    }
-
-    /// \brief Returns the mean length of the found cycle.
-    ///
-    /// Returns the mean length of the found cycle.
-    ///
-    /// \pre \ref run() or \ref findMinMean() must be called before
-    /// using this function.
-    ///
-    /// \note <tt>mmc.cycleMean()</tt> is just a shortcut of the
-    /// following code.
-    /// \code
-    ///   return double(mmc.cycleLength()) / mmc.cycleEdgeNum();
-    /// \endcode
-    double cycleMean() const {
-      return (double)_cycle_length / _cycle_size;
-    }
-
-    /// \brief Returns a const reference to the \ref Path "path"
-    /// structure storing the found cycle.
-    ///
-    /// Returns a const reference to the \ref Path "path"
-    /// structure storing the found cycle.
-    ///
-    /// \pre \ref run() or \ref findCycle() must be called before using
-    /// this function.
-    ///
-    /// \sa cyclePath()
-    const Path& cycle() const {
-      return *_cycle_path;
-    }
-
-    /// \brief Sets the \ref Path "path" structure for storing the found
-    /// cycle.
-    ///
-    /// Sets an external \ref Path "path" structure for storing the
-    /// found cycle.
-    ///
-    /// If you don't call this function before calling \ref run() or
-    /// \ref init(), it will allocate a local \ref Path "path"
-    /// structure.
-    /// The destuctor deallocates this automatically allocated map,
-    /// of course.
-    ///
-    /// \note The algorithm calls only the \ref lemon::Path::addBack()
-    /// "addBack()" function of the given \ref Path "path" structure.
-    ///
-    /// \return <tt>(*this)</tt>
-    ///
-    /// \sa cycle()
-    MinMeanCycle& cyclePath(Path &path) {
-      if (_local_path) {
-        delete _cycle_path;
-        _local_path = false;
-      }
-      _cycle_path = &path;
-      return *this;
-    }
-
   }; //class MinMeanCycle