Context Navigation

← Previous Changeset
Next Changeset →

Changeset 402:235be9d4b6ab in lemon-main

Timestamp:

11/30/08 14:51:05 (16 years ago)

Author:

Peter Kovacs <kpeter@…>

Branch:

default

Phase:

public

Message:

Many doc improvements for Circulation (#175)

More precise doc for members.
Several doc fixes.
Add doc for public types.
Better formulations.
Add useful notes to the problem description.
Use supply instead of excess in the doc.
Hide the doc of the traits class parameter.
Use \tparam for template parameters.

File:

: 1 edited

lemon/circulation.h (modified) (28 diffs)

Legend:

: Unmodified
: Added
: Removed

lemon/circulation.h

-                      r401
+                      r402
 #define LEMON_CIRCULATION_H
-#include <iostream>
-#include <queue>
 #include <lemon/tolerance.h>
 #include <lemon/elevator.h>
 …
 ///\ingroup max_flow
 ///\file
 ///\brief Push-prelabel algorithm for finding a feasible circulation.
+///\brief Push-relabel algorithm for finding a feasible circulation.
 ///
 namespace lemon {
 …
   ///
   /// Default traits class of Circulation class.
+  /// \param _Graph Digraph type.
+  /// \param _CapacityMap Type of capacity map.
+  template <typename _Graph, typename _LCapMap,
+  /// \tparam _Diraph Digraph type.
+  /// \tparam _LCapMap Lower bound capacity map type.
+  /// \tparam _UCapMap Upper bound capacity map type.
+  /// \tparam _DeltaMap Delta map type.
+  template <typename _Diraph, typename _LCapMap,
             typename _UCapMap, typename _DeltaMap>
   struct CirculationDefaultTraits {
     /// \brief The digraph type the algorithm runs on.
     typedef _Graph Digraph;
+    /// \brief The type of the digraph the algorithm runs on.
+    typedef _Diraph Digraph;
     /// \brief The type of the map that stores the circulation lower
 …
     typedef _UCapMap UCapMap;
     /// \brief The type of the map that stores the upper bound of
     /// node excess.
     ///
     /// The type of the map that stores the lower bound of node
     /// excess. It must meet the \ref concepts::ReadMap "ReadMap"
+    /// \brief The type of the map that stores the lower bound for
+    /// the supply of the nodes.
+    ///
+    /// The type of the map that stores the lower bound for the supply
+    /// of the nodes. It must meet the \ref concepts::ReadMap "ReadMap"
     /// concept.
     typedef _DeltaMap DeltaMap;
     /// \brief The type of the length of the arcs.
+    /// \brief The type of the flow values.
     typedef typename DeltaMap::Value Value;
     /// \brief The map type that stores the flow values.
     ///
     /// The map type that stores the flow values.
+    /// \brief The type of the map that stores the flow values.
+    ///
+    /// The type of the map that stores the flow values.
     /// It must meet the \ref concepts::ReadWriteMap "ReadWriteMap" concept.
     typedef typename Digraph::template ArcMap<Value> FlowMap;
 …
+    }
     /// \brief The eleavator type used by Circulation algorithm.
     ///
     /// The elevator type used by Circulation algorithm.
+    /// \brief The elevator type used by the algorithm.
+    ///
+    /// The elevator type used by the algorithm.
     ///
     /// \sa Elevator
 …
     /// \brief Instantiates an Elevator.
     ///
     /// This function instantiates a \ref Elevator.
+    /// This function instantiates an \ref Elevator.
     /// \param digraph The digraph, to which we would like to define
     /// the elevator.
 …
   };
-  ///Push-relabel algorithm for the Network Circulation Problem.
   /**
+     \brief Push-relabel algorithm for the network circulation problem.
      \ingroup max_flow
+     This class implements a push-relabel algorithm
+     or the Network Circulation Problem.
+     This class implements a push-relabel algorithm for the network
+     circulation problem.
+     It is to find a feasible circulation when lower and upper bounds
+     are given for the flow values on the arcs and lower bounds
+     are given for the supply values of the nodes.
      The exact formulation of this problem is the following.
+     \f[\sum_{e\in\rho(v)}x(e)-\sum_{e\in\delta(v)}x(e)\leq
+     -delta(v)\quad \forall v\in V \f]
+     \f[ lo(e)\leq x(e) \leq up(e) \quad \forall e\in E \f]
+     Let \f$G=(V,A)\f$ be a digraph,
+     \f$lower, upper: A\rightarrow\mathbf{R}^+_0\f$,
+     \f$delta: V\rightarrow\mathbf{R}\f$. Find a feasible circulation
+     \f$f: A\rightarrow\mathbf{R}^+_0\f$ so that
+     \f[ \sum_{a\in\delta_{out}(v)} f(a) - \sum_{a\in\delta_{in}(v)} f(a)
+     \geq delta(v) \quad \forall v\in V, \f]
+     \f[ lower(a)\leq f(a) \leq upper(a) \quad \forall a\in A. \f]
+     \note \f$delta(v)\f$ specifies a lower bound for the supply of node
+     \f$v\f$. It can be either positive or negative, however note that
+     \f$\sum_{v\in V}delta(v)\f$ should be zero or negative in order to
+     have a feasible solution.
+     \note A special case of this problem is when
+     \f$\sum_{v\in V}delta(v) = 0\f$. Then the supply of each node \f$v\f$
+     will be \e equal \e to \f$delta(v)\f$, if a circulation can be found.
+     Thus a feasible solution for the
+     \ref min_cost_flow "minimum cost flow" problem can be calculated
+     in this way.
+     \tparam _Digraph The type of the digraph the algorithm runs on.
+     \tparam _LCapMap The type of the lower bound capacity map. The default
+     map type is \ref concepts::Digraph::ArcMap "_Digraph::ArcMap<int>".
+     \tparam _UCapMap The type of the upper bound capacity map. The default
+     map type is \c _LCapMap.
+     \tparam _DeltaMap The type of the map that stores the lower bound
+     for the supply of the nodes. The default map type is
+     \c _Digraph::ArcMap<_UCapMap::Value>.
   */
+  template<class _Graph,
+           class _LCapMap=typename _Graph::template ArcMap<int>,
+           class _UCapMap=_LCapMap,
+           class _DeltaMap=typename _Graph::template NodeMap<
+             typename _UCapMap::Value>,
+           class _Traits=CirculationDefaultTraits<_Graph, _LCapMap,
+                                                  _UCapMap, _DeltaMap> >
+#ifdef DOXYGEN
+template< typename _Digraph,
+          typename _LCapMap,
+          typename _UCapMap,
+          typename _DeltaMap,
+          typename _Traits >
+#else
+template< typename _Digraph,
+          typename _LCapMap = typename _Digraph::template ArcMap<int>,
+          typename _UCapMap = _LCapMap,
+          typename _DeltaMap = typename _Digraph::
+                               template NodeMap<typename _UCapMap::Value>,
+          typename _Traits=CirculationDefaultTraits<_Digraph, _LCapMap,
+                                                    _UCapMap, _DeltaMap> >
+#endif
   class Circulation {
+  public:
+    ///The \ref CirculationDefaultTraits "traits class" of the algorithm.
     typedef _Traits Traits;
+    ///The type of the digraph the algorithm runs on.
     typedef typename Traits::Digraph Digraph;
+    ///The type of the flow values.
+    typedef typename Traits::Value Value;
+    /// The type of the lower bound capacity map.
+    typedef typename Traits::LCapMap LCapMap;
+    /// The type of the upper bound capacity map.
+    typedef typename Traits::UCapMap UCapMap;
+    /// \brief The type of the map that stores the lower bound for
+    /// the supply of the nodes.
+    typedef typename Traits::DeltaMap DeltaMap;
+    ///The type of the flow map.
+    typedef typename Traits::FlowMap FlowMap;
+    ///The type of the elevator.
+    typedef typename Traits::Elevator Elevator;
+    ///The type of the tolerance.
+    typedef typename Traits::Tolerance Tolerance;
+  private:
     TEMPLATE_DIGRAPH_TYPEDEFS(Digraph);
-    typedef typename Traits::Value Value;
-    typedef typename Traits::LCapMap LCapMap;
-    typedef typename Traits::UCapMap UCapMap;
-    typedef typename Traits::DeltaMap DeltaMap;
-    typedef typename Traits::FlowMap FlowMap;
-    typedef typename Traits::Elevator Elevator;
-    typedef typename Traits::Tolerance Tolerance;
-    typedef typename Digraph::template NodeMap<Value> ExcessMap;
     const Digraph &_g;
 …
     bool _local_level;
+    typedef typename Digraph::template NodeMap<Value> ExcessMap;
     ExcessMap* _excess;
 …
     typedef Circulation Create;
     ///\name Named template parameters
+    ///\name Named Template Parameters
     ///@{
 …
     ///
     /// \ref named-templ-param "Named parameter" for setting FlowMap
     /// type
+    /// type.
     template <typename _FlowMap>
     struct SetFlowMap
 …
     ///
     /// \ref named-templ-param "Named parameter" for setting Elevator
+    /// type
+    /// type. If this named parameter is used, then an external
+    /// elevator object must be passed to the algorithm using the
+    /// \ref elevator(Elevator&) "elevator()" function before calling
+    /// \ref run() or \ref init().
+    /// \sa SetStandardElevator
     template <typename _Elevator>
     struct SetElevator
 …
     /// \brief \ref named-templ-param "Named parameter" for setting
     /// Elevator type
+    /// Elevator type with automatic allocation
     ///
     /// \ref named-templ-param "Named parameter" for setting Elevator
+    /// type. The Elevator should be standard constructor interface, ie.
+    /// the digraph and the maximum level should be passed to it.
+    /// type with automatic allocation.
+    /// The Elevator should have standard constructor interface to be
+    /// able to automatically created by the algorithm (i.e. the
+    /// digraph and the maximum level should be passed to it).
+    /// However an external elevator object could also be passed to the
+    /// algorithm with the \ref elevator(Elevator&) "elevator()" function
+    /// before calling \ref run() or \ref init().
+    /// \sa SetElevator
     template <typename _Elevator>
     struct SetStandardElevator
 …
     /// \param lo The lower bound capacity of the arcs.
     /// \param up The upper bound capacity of the arcs.
     /// \param delta The lower bound on node excess.
+    /// \param delta The lower bound for the supply of the nodes.
     Circulation(const Digraph &g,const LCapMap &lo,
                 const UCapMap &up,const DeltaMap &delta)
 …
         _level(0), _local_level(false), _excess(0), _el() {}
     /// Destrcutor.
+    /// Destructor.
     ~Circulation() {
       destroyStructures();
+    }
   private:
 …
     /// Sets the lower bound capacity map.
     /// \return \c (*this)
+    /// \return <tt>(*this)</tt>
     Circulation& lowerCapMap(const LCapMap& map) {
       _lo = &map;
 …
     /// Sets the upper bound capacity map.
     /// \return \c (*this)
+    /// \return <tt>(*this)</tt>
     Circulation& upperCapMap(const LCapMap& map) {
       _up = &map;
 …
+    }
     /// Sets the lower bound map on excess.
     /// Sets the lower bound map on excess.
     /// \return \c (*this)
+    /// Sets the lower bound map for the supply of the nodes.
+    /// Sets the lower bound map for the supply of the nodes.
+    /// \return <tt>(*this)</tt>
     Circulation& deltaMap(const DeltaMap& map) {
       _delta = &map;
 …
+    }
+    /// \brief Sets the flow map.
+    ///
     /// Sets the flow map.
+    /// Sets the flow map.
+    /// \return \c (*this)
+    /// If you don't use this function before calling \ref run() or
+    /// \ref init(), an instance will be allocated automatically.
+    /// The destructor deallocates this automatically allocated map,
+    /// of course.
+    /// \return <tt>(*this)</tt>
     Circulation& flowMap(FlowMap& map) {
       if (_local_flow) {
 …
+    }
+    /// Returns the flow map.
+    /// \return The flow map.
+    ///
+    const FlowMap& flowMap() {
+      return *_flow;
+    }
+    /// Sets the elevator.
+    /// Sets the elevator.
+    /// \return \c (*this)
+    /// \brief Sets the elevator used by algorithm.
+    ///
+    /// Sets the elevator used by algorithm.
+    /// If you don't use this function before calling \ref run() or
+    /// \ref init(), an instance will be allocated automatically.
+    /// The destructor deallocates this automatically allocated elevator,
+    /// of course.
+    /// \return <tt>(*this)</tt>
     Circulation& elevator(Elevator& elevator) {
       if (_local_level) {
 …
+    }
+    /// Returns the elevator.
+    /// \return The elevator.
+    ///
+    /// \brief Returns a const reference to the elevator.
+    ///
+    /// Returns a const reference to the elevator.
+    ///
+    /// \pre Either \ref run() or \ref init() must be called before
+    /// using this function.
     const Elevator& elevator() {
       return *_level;
+    }
+    /// \brief Sets the tolerance used by algorithm.
+    ///
     /// Sets the tolerance used by algorithm.
-    /// Sets the tolerance used by algorithm.
-    ///
     Circulation& tolerance(const Tolerance& tolerance) const {
       _tol = tolerance;
 …
+    }
+    /// Returns the tolerance used by algorithm.
+    /// Returns the tolerance used by algorithm.
+    ///
+    /// \brief Returns a const reference to the tolerance.
+    ///
+    /// Returns a const reference to the tolerance.
     const Tolerance& tolerance() const {
       return tolerance;
+    }
+    /// \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 initial solution or execution then
+    /// you have to call one \ref init() function and then the start()
+    /// function.
+    /// \name Execution Control
+    /// The simplest way to execute the algorithm is to call \ref run().\n
+    /// If you need more control on the initial solution or the execution,
+    /// first you have to call one of the \ref init() functions, then
+    /// the \ref start() function.
     ///@{
 …
     /// Initializes the internal data structures.
+    /// Initializes the internal data structures. This function sets
+    /// all flow values to the lower bound.
+    /// \return This function returns false if the initialization
+    /// process found a barrier.
+    /// Initializes the internal data structures and sets all flow values
+    /// to the lower bound.
     void init()
+    {
 …
+    }
     /// Initializes the internal data structures.
     /// Initializes the internal data structures. This functions uses
     /// greedy approach to construct the initial solution.
+    /// Initializes the internal data structures using a greedy approach.
+    /// Initializes the internal data structures using a greedy approach
+    /// to construct the initial solution.
     void greedyInit()
+    {
 …
+    }
+    ///Starts the algorithm
+    ///This function starts the algorithm.
+    ///\return This function returns true if it found a feasible circulation.
+    ///Executes the algorithm
+    ///This function executes the algorithm.
+    ///
+    ///\return \c true if a feasible circulation is found.
     ///
     ///\sa barrier()
+    ///\sa barrierMap()
     bool start()
+    {
 …
+    }
+    /// Runs the circulation algorithm.
+    /// Runs the circulation algorithm.
+    /// \note fc.run() is just a shortcut of the following code.
+    /// Runs the algorithm.
+    /// This function runs the algorithm.
+    ///
+    /// \return \c true if a feasible circulation is found.
+    ///
+    /// \note Apart from the return value, c.run() is just a shortcut of
+    /// the following code.
     /// \code
     ///   fc.greedyInit();
     ///   return fc.start();
+    ///   c.greedyInit();
+    ///   c.start();
     /// \endcode
     bool run() {
 …
     /// \name Query Functions
+    /// The result of the %Circulation algorithm can be obtained using
+    /// these functions.
+    /// \n
+    /// Before the use of these functions,
+    /// either run() or start() must be called.
+    /// The results of the circulation algorithm can be obtained using
+    /// these functions.\n
+    /// Either \ref run() or \ref start() should be called before
+    /// using them.
     ///@{
+    /// \brief Returns the flow on the given arc.
+    ///
+    /// Returns the flow on the given arc.
+    ///
+    /// \pre Either \ref run() or \ref init() must be called before
+    /// using this function.
+    Value flow(const Arc& arc) const {
+      return (*_flow)[arc];
+    }
+    /// \brief Returns a const reference to the flow map.
+    ///
+    /// Returns a const reference to the arc map storing the found flow.
+    ///
+    /// \pre Either \ref run() or \ref init() must be called before
+    /// using this function.
+    const FlowMap& flowMap() {
+      return *_flow;
+    }
     /**
        \brief Returns a barrier
+       \brief Returns \c true if the given node is in a barrier.
        Barrier is a set \e B of nodes for which
+       \f[ \sum_{v\in B}-delta(v)<
+       \sum_{e\in\rho(B)}lo(e)-\sum_{e\in\delta(B)}up(e) \f]
+       holds. The existence of a set with this property prooves that a feasible
+       flow cannot exists.
+       \f[ \sum_{a\in\delta_{out}(B)} upper(a) -
+           \sum_{a\in\delta_{in}(B)} lower(a) < \sum_{v\in B}delta(v) \f]
+       holds. The existence of a set with this property prooves that a
+       feasible circualtion cannot exist.
+       This function returns \c true if the given node is in the found
+       barrier. If a feasible circulation is found, the function
+       gives back \c false for every node.
+       \pre Either \ref run() or \ref init() must be called before
+       using this function.
+       \sa barrierMap()
        \sa checkBarrier()
-       \sa run()
     */
+    template<class GT>
+    void barrierMap(GT &bar)
+    bool barrier(const Node& node)
+    {
+      return (*_level)[node] >= _el;
+    }
+    /// \brief Gives back a barrier.
+    ///
+    /// This function sets \c bar to the characteristic vector of the
+    /// found barrier. \c bar should be a \ref concepts::WriteMap "writable"
+    /// node map with \c bool (or convertible) value type.
+    ///
+    /// If a feasible circulation is found, the function gives back an
+    /// empty set, so \c bar[v] will be \c false for all nodes \c v.
+    ///
+    /// \note This function calls \ref barrier() for each node,
+    /// so it runs in \f$O(n)\f$ time.
+    ///
+    /// \pre Either \ref run() or \ref init() must be called before
+    /// using this function.
+    ///
+    /// \sa barrier()
+    /// \sa checkBarrier()
+    template<class BarrierMap>
+    void barrierMap(BarrierMap &bar)
+    {
       for(NodeIt n(_g);n!=INVALID;++n)
 …
+    }
-    ///Returns true if the node is in the barrier
-    ///Returns true if the node is in the barrier
-    ///\sa barrierMap()
-    bool barrier(const Node& node)
+    {
-      return (*_level)[node] >= _el;
+    }
-    /// \brief Returns the flow on the arc.
-    ///
-    /// Sets the \c flowMap to the flow on the arcs. This method can
-    /// be called after the second phase of algorithm.
-    Value flow(const Arc& arc) const {
-      return (*_flow)[arc];
+    }
     /// @}
     /// \name Checker Functions
+    /// The feasibility  of the results can be checked using
+    /// these functions.
+    /// \n
+    /// Before the use of these functions,
+    /// either run() or start() must be called.
+    /// The feasibility of the results can be checked using
+    /// these functions.\n
+    /// Either \ref run() or \ref start() should be called before
+    /// using them.
     ///@{
+    ///Check if the  \c flow is a feasible circulation
+    ///Check if the found flow is a feasible circulation
+    ///Check if the found flow is a feasible circulation,
+    ///
     bool checkFlow() {
       for(ArcIt e(_g);e!=INVALID;++e)
 …
     ///Check whether or not the last execution provides a barrier
     ///Check whether or not the last execution provides a barrier
+    ///Check whether or not the last execution provides a barrier.
     ///\sa barrier()
+    ///\sa barrierMap()
     bool checkBarrier()
+    {

Note: See TracChangeset for help on using the changeset viewer.

Context Navigation

Changeset 402:235be9d4b6ab in lemon-main

Legend:

lemon/circulation.h

Download in other formats: