libgecode-dev 3.7.1-3 / usr / include / gecode / int / extensional.hh

/* -*- mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- */
/*
 *  Main authors:
 *     Mikael Lagerkvist <lagerkvist@gecode.org>
 *     Christian Schulte <schulte@gecode.org>
 *
 *  Copyright:
 *     Mikael Lagerkvist, 2007
 *     Christian Schulte, 2004
 *
 *  Last modified:
 *     $Date: 2010-07-14 17:46:18 +0200 (Wed, 14 Jul 2010) $ by $Author: schulte $
 *     $Revision: 11192 $
 *
 *  This file is part of Gecode, the generic constraint
 *  development environment:
 *     http://www.gecode.org
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 *  permit persons to whom the Software is furnished to do so, subject to
 *  the following conditions:
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 *  The above copyright notice and this permission notice shall be
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#ifndef __GECODE_INT_EXTENSIONAL_HH__
#define __GECODE_INT_EXTENSIONAL_HH__

#include <gecode/int.hh>

#include <gecode/int/rel.hh>

/**
 * \namespace Gecode::Int::Extensional
 * \brief %Extensional propagators
 */

namespace Gecode { namespace Int { namespace Extensional {

  /**
   * \brief Domain consistent layered graph (regular) propagator
   *
   * The algorithm for the regular propagator is based on:
   *   Gilles Pesant, A Regular Language Membership Constraint
   *   for Finite Sequences of Variables, CP 2004.
   *   Pages 482-495, LNCS 3258, Springer-Verlag, 2004.
   *
   * The propagator is not capable of dealing with multiple occurences
   * of the same view.
   *
   * Requires \code #include <gecode/int/extensional.hh> \endcode
   * \ingroup FuncIntProp
   */
  template<class View, class Val, class Degree, class StateIdx>
  class LayeredGraph : public Propagator {
  protected:
    /// States are described by number of incoming and outgoing edges
    class State {
    public:
      Degree i_deg; ///< The in-degree (number of incoming edges)
      Degree o_deg; ///< The out-degree (number of outgoing edges)
      /// Initialize with zeroes
      void init(void);
    };
    /// %Edge defined by in-state and out-state
    class Edge {
    public:
      StateIdx i_state; ///< Number of in-state
      StateIdx o_state; ///< Number of out-state
    };
    /// %Support information for a value
    class Support {
    public:
      Val val; ///< Supported value
      Degree n_edges; ///< Number of supporting edges
      Edge* edges; ///< Supporting edges in layered graph
    };
    /// Type for support size
    typedef typename Gecode::Support::IntTypeTraits<Val>::utype ValSize;
    /// %Layer for a view in the layered graph
    class Layer {
    public:
      View x; ///< Integer view
      StateIdx n_states; ///< Number of states used by outgoing edges
      ValSize size; ///< Number of supported values
      State* states; ///< States used by outgoing edges
      Support* support; ///< Supported values
    };
    /// Iterator for telling variable domains by scanning support
    class LayerValues {
    private:
      const Support* s1; ///< Current support
      const Support* s2; ///< End of support
    public:
      /// Default constructor
      LayerValues(void);
      /// Initialize for support of layer \a l
      LayerValues(const Layer& l);
      /// Initialize for support of layer \a l
      void init(const Layer& l);
      /// Test whether more values supported
      bool operator ()(void) const;
      /// Move to next supported value
      void operator ++(void);
      /// Return supported value
      int val(void) const;
    };
    /// %Advisors for views (by position in array)
    class Index : public Advisor {
    public:
      /// The position of the view in the view array
      int i;
      /// Create index advisor
      Index(Space& home, Propagator& p, Council<Index>& c, int i);
      /// Clone index advisor \a a
      Index(Space& home, bool share, Index& a);
    };
    /// Range approximation of which positions have changed
    class IndexRange {
    private:
      int _fst; ///< First index
      int _lst; ///< Last index
    public:
      /// Initialize range as empty
      IndexRange(void);
      /// Reset range to be empty
      void reset(void);
      /// Add index \a i to range
      void add(int i);
      /// Add index range \a ir to range
      void add(const IndexRange& ir);
      /// Shift index range by \a n elements to the left
      void lshift(int n);
      /// Test whether range is empty
      bool empty(void) const;
      /// Return first position
      int fst(void) const;
      /// Return last position
      int lst(void) const;
    };
    /// The advisor council
    Council<Index> c;
    /// Number of layers (and views)
    int n;
    /// The layers of the graph
    Layer* layers;
    /// Maximal number of states per layer
    StateIdx max_states;
    /// Total number of states
    unsigned int n_states;
    /// Total number of edges
    unsigned int n_edges;
    /// Index range with in-degree modifications
    IndexRange i_ch;
    /// Index range with out-degree modifications
    IndexRange o_ch;
    /// Index range for any change (for compression)
    IndexRange a_ch;
    /// Return in state for layer \a i and state index \a is
    State& i_state(int i, StateIdx is);
    /// Return in state for layer \a i and in state of edge \a e
    State& i_state(int i, const Edge& e);
    /// Decrement out degree for in state of edge \a e for layer \a i
    bool i_dec(int i, const Edge& e);
    /// Return out state for layer \a i and state index \a os
    State& o_state(int i, StateIdx os);
    /// Return state for layer \a i and out state of edge \a e
    State& o_state(int i, const Edge& e);
    /// Decrement in degree for out state of edge \a e for layer \a i
    bool o_dec(int i, const Edge& e);
    /// Perform consistency check on data structures
    void audit(void);
    /// Initialize layered graph
    template<class Var>
    ExecStatus initialize(Space& home, 
                          const VarArgArray<Var>& x, const DFA& dfa);
    /// Constructor for cloning \a p
    LayeredGraph(Space& home, bool share,
                 LayeredGraph<View,Val,Degree,StateIdx>& p);
  public:
    /// Constructor for posting
    template<class Var>
    LayeredGraph(Home home, 
                 const VarArgArray<Var>& x, const DFA& dfa);
    /// Copy propagator during cloning
    virtual Actor* copy(Space& home, bool share);
    /// Cost function (defined as high linear)
    virtual PropCost cost(const Space& home, const ModEventDelta& med) const;
    /// Give advice to propagator
    virtual ExecStatus advise(Space& home, Advisor& a, const Delta& d);
    /// Perform propagation
    virtual ExecStatus propagate(Space& home, const ModEventDelta& med);
    /// Delete propagator and return its size
    virtual size_t dispose(Space& home);
    /// Post propagator on views \a x and DFA \a dfa
    template<class Var>
    static ExecStatus post(Home home, 
                           const VarArgArray<Var>& x, const DFA& dfa);
  };

  /// Select small types for the layered graph propagator
  template<class Var>
  ExecStatus post_lgp(Home home, 
                      const VarArgArray<Var>& x, const DFA& dfa);

}}}

#include <gecode/int/extensional/layered-graph.hpp>


namespace Gecode { namespace Int { namespace Extensional {

  typedef TupleSet::Tuple Tuple;
  typedef Support::BitSetBase BitSet;
  typedef Support::BitSetBase* Domain;

  /**
   * \brief %Base for domain consistent extensional propagation
   *
   * This class contains support for implementing domain consistent
   * extensional propagation algorithms that use positive tuple sets and
   * a \a last data structure.
   *
   * Requires \code #include <gecode/int/extensional.hh> \endcode
   * \ingroup FuncIntProp
   */
  template<class View, bool subscribe = true>
  class Base : public Propagator {
  protected:
    ViewArray<View> x; ///< Variables
    TupleSet tupleSet; ///< Definition of constraint
    Tuple** last_data; ///< Last tuple looked at
    /// Access real tuple-set
    TupleSet::TupleSetI* ts(void);

    /// Constructor for cloning \a p
    Base(Space& home, bool share, Base<View,subscribe>& p);
    /// Constructor for posting
    Base(Home home, ViewArray<View>& x, const TupleSet& t);
    /// Initialize last support
    void init_last(Space& home, Tuple** source);
    /// Find last support for view at position \a i and value \a n
    Tuple last(int i, int n);
    /// Find last support for view at position \a i and value \a n
    Tuple last_next(int i, int n);
    /// Initialize domain information
    void init_dom(Space& home, Domain dom);
    /// Check wether tuple is valid for domain
    bool valid(Tuple t, Domain dom);
    /// Find support for view at position \a i and value \a n
    Tuple find_support(Domain dom, int i, int n);
  public:
    /// Cost function (defined as high quadratic)
    virtual PropCost cost(const Space& home, const ModEventDelta& med) const;
    /// Delete propagator and return its size
    virtual size_t dispose(Space& home);
  protected:
    /// Unused destructor (to avoid warnings)
    virtual ~Base(void) {}
  };
}}}

#include <gecode/int/extensional/base.hpp>


namespace Gecode { namespace Int { namespace Extensional {

  /**
   * \brief Domain consistent extensional propagator
   *
   * This propagator implements a basic extensional propagation
   * algorithm. It is based on GAC2001, and as such it does not fully
   * take into account multidirectionality.
   *
   * If \a shared is true, the same view can occur multiply.
   *
   * Requires \code #include <gecode/int/extensional.hh> \endcode
   * \ingroup FuncIntProp
   */
  template<class View, bool shared>
  class Basic : public Base<View> {
  protected:
    using Base<View>::x;
    using Base<View>::tupleSet;
    using Base<View>::ts;
    using Base<View>::last;
    using Base<View>::last_next;
    using Base<View>::init_last;
    using Base<View>::init_dom;
    using Base<View>::find_support;

    /// Constructor for cloning \a p
    Basic(Space& home, bool share, Basic<View,shared>& p);
    /// Constructor for posting
    Basic(Home home, ViewArray<View>& x, const TupleSet& t);

  public:
    /// Perform propagation
    virtual ExecStatus propagate(Space& home, const ModEventDelta& med);
    /**
     * \brief Cost function
     *
     * If in stage for naive value propagation, the cost is
     * high quadratic. Otherwise it is high cubic.
     */
    virtual PropCost cost(const Space& home, const ModEventDelta& med) const;
    /// Copy propagator during cloning
    virtual Actor* copy(Space& home, bool share);
    /// Post propagator for views \a x
    static ExecStatus post(Home home, ViewArray<View>& x, const TupleSet& t);
  };

}}}

#include <gecode/int/extensional/basic.hpp>


namespace Gecode { namespace Int { namespace Extensional {
  /**
   * \brief Domain consistent extensional propagator
   *
   * This propagator implements an incremental propagation algorithm
   * where supports are maintained explicitly.
   *
   * Requires \code #include <gecode/int/extensional.hh> \endcode
   * \ingroup FuncIntProp
   */
  template<class View>
  class Incremental : public Base<View, false> {
  protected:
    using Base<View, false>::x;
    using Base<View, false>::tupleSet;
    using Base<View, false>::ts;
    using Base<View, false>::last;
    using Base<View, false>::last_next;
    using Base<View, false>::init_last;
    using Base<View, false>::init_dom;
    /// Entry for storing support
    class SupportEntry : public FreeList {
    public:
      /// Supporting Tuple
      Tuple t;

      /// \name Linkage access
      //@{
      /// Return next support entry
      SupportEntry* next(void) const;
      /// Return reference to field for next support entry
      SupportEntry** nextRef(void);
      //@}

      /// \name Constructors
      //@{
      /// Initialize with Tuple \a t
      SupportEntry(Tuple t);
      /// Initialize with Tuple \a t and next entry \a n
      SupportEntry(Tuple t, SupportEntry* n);
      //@}

      /// \name Memory management
      //@{
      /// Free memory for all elements between this and \a l (inclusive)
      void dispose(Space& home, SupportEntry* l);
      /// Free memory for this element
      void dispose(Space& home);

      /// Allocate memory from space
      static void* operator new(size_t s, Space& home);
      /// No-op (for exceptions)
      static void operator delete(void* p);
      /// No-op (use dispose instead)
      static void operator delete(void* p, Space& home);
      //@}
    };
    /// Description of work to be done
    class WorkEntry : public FreeList {
    public:
      /// Position of view in view array
      int i;
      /// Value
      int n;

      /// \name Constructor
      //@{
      /// Initialize with position \a i, value \a n, and next entry \a ne
      WorkEntry(int i, int n, WorkEntry* ne);
      //@}

      /// \name Linkage access
      //@{
      /// Return next work entry
      WorkEntry* next(void) const;
      /// Set next work entry
      void next(WorkEntry* n);
      //@}

      /// \name Memory management
      //@{
      /// Free memory for this element
      void dispose(Space& home);

      /// Allocate memory from space
      static void* operator new(size_t s, Space& home);
      /// No-op (for exceptions)
      static void operator delete(void* p);
      /// No-op (use dispose instead)
      static void operator delete(void* p, Space& home);
      //@}
    };
    /// %Work stack
    class Work {
    private:
      /// Next work entry
      WorkEntry* we;
    public:
      /// Initialize as empty
      Work(void);
      /// Check whether work stack is empty
      bool empty(void) const;
      /// Push new work entry for position \a i and value \a n
      void push(Space& home, int i, int n);
      /// Pop current top entry and set position \a i and value \a n
      void pop(Space& home, int& i, int& n);
    };
    /// Work for finding support
    Work w_support;
    /// Work for removing values
    Work w_remove;

    /// Support information
    SupportEntry** support_data;
    /// Number of unassigned views
    int unassigned;

    /// Constructor for cloning \a p
    Incremental(Space& home, bool share, Incremental<View>& p);
    /// Constructor for posting
    Incremental(Home home, ViewArray<View>& x, const TupleSet& t);
    /// Initialize support
    void init_support(Space& home);
    /// Find a next support for view at position \a i and value \a n
    void find_support(Space& home, Domain dom, int i, int n);
    /// Add support
    void add_support(Space& home, Tuple l);
    /// Remove support for view at position \a i and value \a n
    void remove_support(Space& home, Tuple l, int i, int n);
    /// Creat support entry for view at position \a i and value \a n
    SupportEntry* support(int i, int n);
  public:
    /// Perform propagation
    virtual ExecStatus propagate(Space& home, const ModEventDelta& med);
    /**
     * \brief Cost function
     *
     * If in stage for naive value propagation, the cost is
     * high quadratic. Otherwise it is high cubic.
     */
    virtual PropCost cost(const Space& home, const ModEventDelta& med) const;
    /// Copy propagator during cloning
    virtual Actor* copy(Space& home, bool share);
    /// Post propagator for views \a x
    static ExecStatus post(Home home, ViewArray<View>& x, const TupleSet& t);
    /// Delete propagator and return its size
    size_t dispose(Space& home);
  private:
    /// Advisor for computing support
    class SupportAdvisor : public Advisor {
    public:
      /// Position of view
      int i;
      /// Create support advisor for view at position \a i
      SupportAdvisor(Space& home, Propagator& p, Council<SupportAdvisor>& c,
                     int i);
      /// Clone support advisor \a a
      SupportAdvisor(Space& home, bool share, SupportAdvisor& a);
      /// Dispose advisor
      void dispose(Space& home, Council<SupportAdvisor>& c);
    };
    /// The advisor council
    Council<SupportAdvisor> ac;
  public:
    /// Give advice to propagator
    virtual ExecStatus advise(Space& home, Advisor& a, const Delta& d);
  };

}}}

#include <gecode/int/extensional/incremental.hpp>


#endif

// STATISTICS: int-prop