Subversion Repositories Games.Chess Giants

/*

  Stockfish, a UCI chess playing engine derived from Glaurung 2.1

  Copyright (C) 2004-2008 Tord Romstad (Glaurung author)

  Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad

  Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad

  Stockfish is free software: you can redistribute it and/or modify

  it under the terms of the GNU General Public License as published by

  the Free Software Foundation, either version 3 of the License, or

  (at your option) any later version.

  Stockfish is distributed in the hope that it will be useful,

  but WITHOUT ANY WARRANTY; without even the implied warranty of

  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License

  along with this program.  If not, see <http://www.gnu.org/licenses/>.

*/

#ifndef THREAD_H_INCLUDED

#define THREAD_H_INCLUDED

#include <atomic>

#include <condition_variable>

#include <mutex>

#include <thread>

#include <vector>

#include "material.h"

#include "movepick.h"

#include "pawns.h"

#include "position.h"

#include "search.h"

#include "thread_win32.h"

/// Thread class keeps together all the thread-related stuff. We use

/// per-thread pawn and material hash tables so that once we get a

/// pointer to an entry its life time is unlimited and we don't have

/// to care about someone changing the entry under our feet.

class Thread {

  Mutex mutex;

  ConditionVariable cv;

  size_t idx;

  bool exit = false, searching = true; // Set before starting std::thread

  std::thread stdThread;

public:

  explicit Thread(size_t);

  virtual ~Thread();

  virtual void search();

  void clear();

  void idle_loop();

  void start_searching();

  void wait_for_search_finished();

  Pawns::Table pawnsTable;

  Material::Table materialTable;

  Endgames endgames;

  size_t PVIdx;

  int selDepth, nmp_ply, nmp_odd;

  std::atomic<uint64_t> nodes, tbHits;

  Position rootPos;

  Search::RootMoves rootMoves;

  Depth rootDepth, completedDepth;

  CounterMoveHistory counterMoves;

  ButterflyHistory mainHistory;

  CapturePieceToHistory captureHistory;

  ContinuationHistory contHistory;

};

/// MainThread is a derived class specific for main thread

struct MainThread : public Thread {

  using Thread::Thread;

  void search() override;

  void check_time();

  bool failedLow;

  double bestMoveChanges, previousTimeReduction;

  Value previousScore;

  int callsCnt;

};

/// ThreadPool struct handles all the threads-related stuff like init, starting,

/// parking and, most importantly, launching a thread. All the access to threads

/// is done through this class.

struct ThreadPool : public std::vector<Thread*> {

  void start_thinking(Position&, StateListPtr&, const Search::LimitsType&, bool = false);

  void clear();

  void set(size_t);

  MainThread* main()        const { return static_cast<MainThread*>(front()); }

  uint64_t nodes_searched() const { return accumulate(&Thread::nodes); }

  uint64_t tb_hits()        const { return accumulate(&Thread::tbHits); }

  std::atomic_bool stop, ponder, stopOnPonderhit;

private:

  StateListPtr setupStates;

  uint64_t accumulate(std::atomic<uint64_t> Thread::* member) const {

    uint64_t sum = 0;

    for (Thread* th : *this)

        sum += (th->*member).load(std::memory_order_relaxed);

    return sum;

  }

};

extern ThreadPool Threads;

#endif // #ifndef THREAD_H_INCLUDED