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stockfish/src/search.h

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/*
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) 2015-2016 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 SEARCH_H_INCLUDED
#define SEARCH_H_INCLUDED
#include <atomic>
#include <vector>
#include "misc.h"
#include "position.h"
#include "types.h"
template<typename T, bool CM> struct Stats;
typedef Stats<Value, true> CounterMoveStats;
namespace Search {
/// Stack struct keeps track of the information we need to remember from nodes
/// shallower and deeper in the tree during the search. Each search thread has
/// its own array of Stack objects, indexed by the current ply.
struct Stack {
Move* pv;
int ply;
Move currentMove;
Move excludedMove;
Move killers[2];
Value staticEval;
bool skipEarlyPruning;
int moveCount;
CounterMoveStats* counterMoves;
};
/// RootMove struct is used for moves at the root of the tree. For each root move
/// we store a score and a PV (really a refutation in the case of moves which
/// fail low). Score is normally set at -VALUE_INFINITE for all non-pv moves.
struct RootMove {
explicit RootMove(Move m) : pv(1, m) {}
bool operator<(const RootMove& m) const { return m.score < score; } // Descending sort
bool operator==(const Move& m) const { return pv[0] == m; }
void insert_pv_in_tt(Position& pos);
bool extract_ponder_from_tt(Position& pos);
Value score = -VALUE_INFINITE;
Value previousScore = -VALUE_INFINITE;
std::vector<Move> pv;
};
typedef std::vector<RootMove> RootMoves;
/// LimitsType struct stores information sent by GUI about available time to
/// search the current move, maximum depth/time, if we are in analysis mode or
/// if we have to ponder while it's our opponent's turn to move.
struct LimitsType {
LimitsType() { // Init explicitly due to broken value-initialization of non POD in MSVC
nodes = time[WHITE] = time[BLACK] = inc[WHITE] = inc[BLACK] =
npmsec = movestogo = depth = movetime = mate = infinite = ponder = 0;
}
bool use_time_management() const {
return !(mate | movetime | depth | nodes | infinite);
}
std::vector<Move> searchmoves;
int time[COLOR_NB], inc[COLOR_NB], npmsec, movestogo, depth, movetime, mate, infinite, ponder;
int64_t nodes;
TimePoint startTime;
};
/// The SignalsType struct stores atomic flags updated during the search
/// typically in an async fashion e.g. to stop the search by the GUI.
struct SignalsType {
std::atomic_bool stop, stopOnPonderhit;
};
extern SignalsType Signals;
extern LimitsType Limits;
void init();
void clear();
template<bool Root = true> uint64_t perft(Position& pos, Depth depth);
} // namespace Search
#endif // #ifndef SEARCH_H_INCLUDED