engine.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, 2009
 *     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_ENGINE_HH
#define GECODE_SEARCH_PAR_ENGINE_HH
 
#include <gecode/search.hh>
#include <gecode/search/support.hh>
#include <gecode/search/worker.hh>
#include <gecode/search/par/path.hh>
#include <atomic>
 
namespace Gecode { namespace Search { namespace Par {

  template<class Tracer>
  class Engine : public Search::Engine, public Support::Terminator {
  protected:
    class Worker : public Search::Worker, public Support::Runnable {
    public:
      Tracer tracer;
    protected:
      Engine& _engine;
      Support::Mutex m;
      Path<Tracer> path;
      Space* cur;
      unsigned int d;
      bool idle;
    public:
      Worker(Space* s, Engine& e);
      Space* steal(unsigned long int& d, Tracer& myt, Tracer& ot);
      Statistics statistics(void);
      Engine& engine(void) const;
      NoGoods& nogoods(void);
      virtual ~Worker(void);
      virtual Support::Terminator* terminator(void) const;
    };

    Options _opt;
  public:
    const Options& opt(void) const;
    unsigned int workers(void) const;



    enum Cmd {
      C_WORK,     
      C_WAIT,     
      C_RESET,    
      C_TERMINATE 
    };
  protected:
    std::atomic<Cmd> _cmd;
    Support::Mutex _m_wait;
  public:
    Cmd cmd(void) const;
    void block(void);
    void release(Cmd c);
    void wait(void);


  protected:
    Support::Mutex _m_term;
    volatile unsigned int _n_term_not_ack;
    Support::Event _e_term_ack;
    Support::Mutex _m_wait_terminate;
    volatile unsigned int _n_not_terminated;
    Support::Event _e_terminate;
  public:
    void ack_terminate(void);
    virtual void terminated(void);
    void wait_terminate(void);
    void terminate(void);


  protected:
    Support::Mutex _m_reset;
    volatile unsigned int _n_reset_not_ack;
    Support::Event e_reset_ack_start;
    Support::Event e_reset_ack_stop;
    Support::Mutex m_wait_reset;
  public:
    void ack_reset_start(void);
    void ack_reset_stop(void);
    void wait_reset(void);


  protected:
    Support::Mutex m_search;
    Support::Event e_search;
    Support::DynamicQueue<Space*,Heap> solutions;
    volatile unsigned int n_busy;
    std::atomic<bool> has_stopped;
    bool signal(void) const;
  public:
    void idle(void);
    void busy(void);
    void stop(void);



    Engine(const Options& o);
    virtual Space* next(void);
    virtual bool stopped(void) const;

    virtual ~Engine(void);
  };
 
}}}
 
#include <gecode/search/par/engine.hpp>
 
#endif
 
// STATISTICS: search-par