pbs.hh

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/* -*- mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- */
/*
 *  Main authors:
 *     Christian Schulte <schulte@gecode.dev>
 *
 *  Contributing authors:
 *     Mikael Zayenz Lagerkvist <lagerkvist@gecode.dev>
 *
 *  Copyright:
 *     Christian Schulte, 2015
 *     Mikael Zayenz Lagerkvist, 2026
 *
 *  This file is part of Gecode, the generic constraint
 *  development environment:
 *     http://www.gecode.dev
 *
 *  Permission is hereby granted, free of charge, to any person obtaining
 *  a copy of this software and associated documentation files (the
 *  "Software"), to deal in the Software without restriction, including
 *  without limitation the rights to use, copy, modify, merge, publish,
 *  distribute, sublicense, and/or sell copies of the Software, and to
 *  permit persons to whom the Software is furnished to do so, subject to
 *  the following conditions:
 *
 *  The above copyright notice and this permission notice shall be
 *  included in all copies or substantial portions of the Software.
 *
 *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 *  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 *  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 *  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 *  LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 *  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 *  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 */
 
#ifndef GECODE_SEARCH_PAR_PBS_HH
#define GECODE_SEARCH_PAR_PBS_HH
 
#include <gecode/search.hh>
#include <atomic>
 
namespace Gecode { namespace Search { namespace Par {

  class GECODE_SEARCH_EXPORT PortfolioStop : public Stop {
  private:
    Stop* so;
    std::atomic<bool>* tostop;
  public:
    PortfolioStop(Stop* so);
    void share(std::atomic<bool>* ts);
    virtual bool stop(const Statistics& s, const Options& o);
    void stop(bool s);
    bool stop(void) const;
  };
 
  // Forward declaration
  template<class Collect>
  class PBS;

  template<class Collect>
  class GECODE_SEARCH_EXPORT Slave : public Support::Runnable {
  protected:
    class Completion : public Support::Terminator {
    protected:
      Support::Event done;
    public:
      Completion(void);
      virtual void terminated(void);
      void wait(void);
    } completion;

    PBS<Collect>* master;
    Engine* slave;
    Stop* stop;
  public:
    Slave(PBS<Collect>* m, Engine* s, Stop* so);
    Statistics statistics(void) const;
    bool stopped(void) const;
    virtual Support::Terminator* terminator(void) const;
    void wait(void);
    void constrain(const Space& b);
    virtual void run(void);
    virtual ~Slave(void);
  };

  class CollectAll {
  protected:
    Support::DynamicQueue<Space*,Heap> solutions;
  public:
    static const bool best = false;
    CollectAll(void);
    bool add(Space* s, Slave<CollectAll>* r);
    bool constrain(const Space& b);
    bool empty(void) const;
    Space* get(Slave<CollectAll>*& r);
    ~CollectAll(void);
  };

  class CollectBest {
  protected:
    Space* b;
    Slave<CollectBest>* reporter;
  public:
    static const bool best = true;
    CollectBest(void);
    bool add(Space* s, Slave<CollectBest>* r);
    bool constrain(const Space& b);
    bool empty(void) const;
    Space* get(Slave<CollectBest>*& r);
    ~CollectBest(void);
  };

  template<class Collect>
  class GECODE_SEARCH_EXPORT PBS : public Engine {
    friend class Slave<Collect>;
  protected:
    Statistics stat;
    Slave<Collect>** slaves;
    unsigned int n_slaves;
    unsigned int n_active;
    std::atomic<bool> slave_stop;
    std::atomic<bool> tostop;
    Collect solutions;
    Support::Mutex m;
    unsigned int n_busy;
    Support::Event idle;
    bool report(Slave<Collect>* slave, Space* s);
  public:
    PBS(Engine** s, Stop** so, unsigned int n, const Statistics& stat);
    virtual Space* next(void);
    virtual Statistics statistics(void) const;
    virtual bool stopped(void) const;
    virtual void constrain(const Space& b);
    virtual ~PBS(void);
  };
 
}}}
 
#include <gecode/search/par/pbs.hpp>
 
#endif
 
// STATISTICS: search-par