Changeset 596:293551ad254f in lemon-1.2 for lemon/gomory_hu.h

Timestamp:

04/15/09 09:37:51 (16 years ago)

Author:

Peter Kovacs <kpeter@…>

Branch:

default

Phase:

public

Message:

Improvements and fixes for the minimum cut algorithms (#264)

File:

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

lemon/gomory_hu.h

@@ -43 +43 @@
   /// between these nodes. Moreover the components obtained by removing
   /// this edge from the tree determine the corresponding minimum cut.
-  ///
   /// Therefore once this tree is computed, the minimum cut between any pair
   /// of nodes can easily be obtained.
   /// 
   /// The algorithm calculates \e n-1 distinct minimum cuts (currently with
-  /// the \ref Preflow algorithm), therefore the algorithm has
-  /// \f$(O(n^3\sqrt{e})\f$ overall time complexity. It calculates a
-  /// rooted Gomory-Hu tree, its structure and the weights can be obtained
-  /// by \c predNode(), \c predValue() and \c rootDist().
-  /// 
-  /// The members \c minCutMap() and \c minCutValue() calculate
+  /// the \ref Preflow algorithm), thus it has \f$O(n^3\sqrt{e})\f$ overall
+  /// time complexity. It calculates a rooted Gomory-Hu tree.
+  /// The structure of the tree and the edge weights can be
+  /// obtained using \c predNode(), \c predValue() and \c rootDist().
+  /// The functions \c minCutMap() and \c minCutValue() calculate
   /// the minimum cut and the minimum cut value between any two nodes
   /// in the graph. You can also list (iterate on) the nodes and the
@@ -59 +57 @@
   ///
   /// \tparam GR The type of the undirected graph the algorithm runs on.
-  /// \tparam CAP The type of the edge map describing the edge capacities.
-  /// It is \ref concepts::Graph::EdgeMap "GR::EdgeMap<int>" by default.
+  /// \tparam CAP The type of the edge map containing the capacities.
+  /// The default map type is \ref concepts::Graph::EdgeMap "GR::EdgeMap<int>".
 #ifdef DOXYGEN
   template <typename GR,
@@ -71 +69 @@
   public:
 
-    /// The graph type
+    /// The graph type of the algorithm
     typedef GR Graph;
-    /// The type of the edge capacity map
+    /// The capacity map type of the algorithm
     typedef CAP Capacity;
     /// The value type of capacities
@@ -118 +116 @@
     /// \brief Constructor
     ///
-    /// Constructor
+    /// Constructor.
     /// \param graph The undirected graph the algorithm runs on.
     /// \param capacity The edge capacity map.
@@ -131 +129 @@
     /// \brief Destructor
     ///
-    /// Destructor
+    /// Destructor.
     ~GomoryHu() {
       destroyStructures();
@@ -216 +214 @@
     ///The results of the algorithm can be obtained using these
     ///functions.\n
-    ///\ref run() "run()" should be called before using them.\n
+    ///\ref run() should be called before using them.\n
     ///See also \ref MinCutNodeIt and \ref MinCutEdgeIt.
 
@@ -223 +221 @@
     /// \brief Return the predecessor node in the Gomory-Hu tree.
     ///
-    /// This function returns the predecessor node in the Gomory-Hu tree.
-    /// If the node is
-    /// the root of the Gomory-Hu tree, then it returns \c INVALID.
-    Node predNode(const Node& node) {
+    /// This function returns the predecessor node of the given node
+    /// in the Gomory-Hu tree.
+    /// If \c node is the root of the tree, then it returns \c INVALID.
+    ///
+    /// \pre \ref run() must be called before using this function.
+    Node predNode(const Node& node) const {
       return (*_pred)[node];
-    }
-
-    /// \brief Return the distance from the root node in the Gomory-Hu tree.
-    ///
-    /// This function returns the distance of \c node from the root node
-    /// in the Gomory-Hu tree.
-    int rootDist(const Node& node) {
-      return (*_order)[node];
     }
 
@@ -241 +233 @@
     /// Gomory-Hu tree.
     ///
-    /// This function returns the weight of the predecessor edge in the
-    /// Gomory-Hu tree.  If the node is the root, the result is undefined.
-    Value predValue(const Node& node) {
+    /// This function returns the weight of the predecessor edge of the 
+    /// given node in the Gomory-Hu tree.
+    /// If \c node is the root of the tree, the result is undefined.
+    ///
+    /// \pre \ref run() must be called before using this function.
+    Value predValue(const Node& node) const {
       return (*_weight)[node];
     }
 
+    /// \brief Return the distance from the root node in the Gomory-Hu tree.
+    ///
+    /// This function returns the distance of the given node from the root
+    /// node in the Gomory-Hu tree.
+    ///
+    /// \pre \ref run() must be called before using this function.
+    int rootDist(const Node& node) const {
+      return (*_order)[node];
+    }
+
     /// \brief Return the minimum cut value between two nodes
     ///
-    /// This function returns the minimum cut value between two nodes. The
-    /// algorithm finds the nearest common ancestor in the Gomory-Hu
-    /// tree and calculates the minimum weight edge on the paths to
-    /// the ancestor.
+    /// This function returns the minimum cut value between the nodes
+    /// \c s and \c t. 
+    /// It finds the nearest common ancestor of the given nodes in the
+    /// Gomory-Hu tree and calculates the minimum weight edge on the
+    /// paths to the ancestor.
+    ///
+    /// \pre \ref run() must be called before using this function.
     Value minCutValue(const Node& s, const Node& t) const {
       Node sn = s, tn = t;
@@ -275 +283 @@
     /// \c s to \c true and the other nodes to \c false.
     ///
-    /// For higher level interfaces, see MinCutNodeIt and MinCutEdgeIt.
+    /// For higher level interfaces see MinCutNodeIt and MinCutEdgeIt.
+    ///
+    /// \param s The base node.
+    /// \param t The node you want to separate from node \c s.
+    /// \param cutMap The cut will be returned in this map.
+    /// It must be a \c bool (or convertible) \ref concepts::ReadWriteMap
+    /// "ReadWriteMap" on the graph nodes.
+    ///
+    /// \return The value of the minimum cut between \c s and \c t.
+    ///
+    /// \pre \ref run() must be called before using this function.
     template <typename CutMap>
-    Value minCutMap(const Node& s, ///< The base node.
+    Value minCutMap(const Node& s, ///< 
                     const Node& t,
-                    ///< The node you want to separate from node \c s.
+                    ///< 
                     CutMap& cutMap
-                    ///< The cut will be returned in this map.
-                    /// It must be a \c bool (or convertible) 
-                    /// \ref concepts::ReadWriteMap "ReadWriteMap"
-                    /// on the graph nodes.
+                    ///< 
                     ) const {
       Node sn = s, tn = t;
@@ -339 +354 @@
     
     /// This iterator class lists the nodes of a minimum cut found by
-    /// GomoryHu. Before using it, you must allocate a GomoryHu class,
+    /// GomoryHu. Before using it, you must allocate a GomoryHu class
     /// and call its \ref GomoryHu::run() "run()" method.
     ///
@@ -436 +451 @@
     
     /// This iterator class lists the edges of a minimum cut found by
-    /// GomoryHu. Before using it, you must allocate a GomoryHu class,
+    /// GomoryHu. Before using it, you must allocate a GomoryHu class
     /// and call its \ref GomoryHu::run() "run()" method.
     ///
@@ -448 +463 @@
     ///   value+=capacities[e];
     /// \endcode
-    /// the result will be the same as it is returned by
-    /// \ref GomoryHu::minCutValue() "gom.minCutValue(s,t)"
+    /// The result will be the same as the value returned by
+    /// \ref GomoryHu::minCutValue() "gom.minCutValue(s,t)".
     class MinCutEdgeIt
     {
@@ -469 +484 @@
       
     public:
+      /// Constructor
+
+      /// Constructor.
+      ///
       MinCutEdgeIt(GomoryHu const &gomory,
                    ///< The GomoryHu class. You must call its
@@ -479 +498 @@
                    ///< If it is \c true (default) then the listed arcs
                    ///  will be oriented from the
-                   ///  the nodes of the component containing \c s,
+                   ///  nodes of the component containing \c s,
                    ///  otherwise they will be oriented in the opposite
                    ///  direction.