2 Stockfish, a UCI chess playing engine derived from Glaurung 2.1
3 Copyright (C) 2004-2023 The Stockfish developers (see AUTHORS file)
5 Stockfish is free software: you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation, either version 3 of the License, or
8 (at your option) any later version.
10 Stockfish is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with this program. If not, see <http://www.gnu.org/licenses/>.
19 #ifndef THREAD_H_INCLUDED
20 #define THREAD_H_INCLUDED
23 #include <condition_variable>
32 #include "thread_win32_osx.h"
37 // Thread class keeps together all the thread-related stuff.
41 std::condition_variable cv;
43 bool exit = false, searching = true; // Set before starting std::thread
44 NativeThread stdThread;
47 explicit Thread(size_t);
49 virtual void search();
52 void start_searching();
53 void wait_for_search_finished();
54 size_t id() const { return idx; }
57 std::atomic<uint64_t> nodes, tbHits, bestMoveChanges;
58 int selDepth, nmpMinPly;
59 Value bestValue, optimism[COLOR_NB];
63 Search::RootMoves rootMoves;
64 Depth rootDepth, completedDepth;
67 CounterMoveHistory counterMoves;
68 ButterflyHistory mainHistory;
69 CapturePieceToHistory captureHistory;
70 ContinuationHistory continuationHistory[2][2];
71 PawnHistory pawnHistory;
75 // MainThread is a derived class specific for main thread
76 struct MainThread: public Thread {
80 void search() override;
83 double previousTimeReduction;
84 Value bestPreviousScore;
85 Value bestPreviousAverageScore;
89 std::atomic_bool ponder;
93 // ThreadPool struct handles all the threads-related stuff like init, starting,
94 // parking and, most importantly, launching a thread. All the access to threads
95 // is done through this class.
98 void start_thinking(Position&, StateListPtr&, const Search::LimitsType&, bool = false);
102 MainThread* main() const { return static_cast<MainThread*>(threads.front()); }
103 uint64_t nodes_searched() const { return accumulate(&Thread::nodes); }
104 uint64_t tb_hits() const { return accumulate(&Thread::tbHits); }
105 Thread* get_best_thread() const;
106 void start_searching();
107 void wait_for_search_finished() const;
109 std::atomic_bool stop, increaseDepth;
111 auto cbegin() const noexcept { return threads.cbegin(); }
112 auto begin() noexcept { return threads.begin(); }
113 auto end() noexcept { return threads.end(); }
114 auto cend() const noexcept { return threads.cend(); }
115 auto size() const noexcept { return threads.size(); }
116 auto empty() const noexcept { return threads.empty(); }
119 StateListPtr setupStates;
120 std::vector<Thread*> threads;
122 uint64_t accumulate(std::atomic<uint64_t> Thread::*member) const {
125 for (Thread* th : threads)
126 sum += (th->*member).load(std::memory_order_relaxed);
131 extern ThreadPool Threads;
133 } // namespace Stockfish
135 #endif // #ifndef THREAD_H_INCLUDED