/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
- Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2013 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2004-2021 The Stockfish developers (see AUTHORS file)
Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
-#if !defined(SEARCH_H_INCLUDED)
+#ifndef SEARCH_H_INCLUDED
#define SEARCH_H_INCLUDED
-#include <cstring>
-#include <memory>
-#include <stack>
#include <vector>
#include "misc.h"
-#include "position.h"
+#include "movepick.h"
#include "types.h"
-struct SplitPoint;
+namespace Stockfish {
+
+class Position;
namespace Search {
-/// The 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.
+/// Threshold used for countermoves based pruning
+constexpr int CounterMovePruneThreshold = 0;
+
+
+/// 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 {
- SplitPoint* splitPoint;
+ Move* pv;
+ PieceToHistory* continuationHistory;
int ply;
Move currentMove;
Move excludedMove;
Move killers[2];
- Depth reduction;
Value staticEval;
- Value evalMargin;
- int skipNullMove;
- int futilityMoveCount;
+ int statScore;
+ int moveCount;
+ bool inCheck;
+ bool ttPv;
+ bool ttHit;
+ int doubleExtensions;
};
-/// RootMove struct is used for moves at the root of the tree. For each root
-/// move we store a score, a node count, 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 {
+/// 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.
- RootMove(Move m) : score(-VALUE_INFINITE), prevScore(-VALUE_INFINITE) {
- pv.push_back(m); pv.push_back(MOVE_NONE);
- }
+struct RootMove {
- bool operator<(const RootMove& m) const { return score > m.score; } // Ascending sort
+ explicit RootMove(Move m) : pv(1, m) {}
+ bool extract_ponder_from_tt(Position& pos);
bool operator==(const Move& m) const { return pv[0] == m; }
+ bool operator<(const RootMove& m) const { // Sort in descending order
+ return m.score != score ? m.score < score
+ : m.previousScore < previousScore;
+ }
- void extract_pv_from_tt(Position& pos);
- void insert_pv_in_tt(Position& pos);
-
- Value score;
- Value prevScore;
+ Value score = -VALUE_INFINITE;
+ Value previousScore = -VALUE_INFINITE;
+ int selDepth = 0;
+ int tbRank = 0;
+ Value tbScore;
std::vector<Move> pv;
};
+typedef std::vector<RootMove> RootMoves;
-/// The 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 is our opponent's side to move.
-struct LimitsType {
-
- LimitsType() { memset(this, 0, sizeof(LimitsType)); }
- bool use_time_management() const { return !(mate | movetime | depth | nodes | infinite); }
+/// LimitsType struct stores information sent by GUI about available time to
+/// search the current move, maximum depth/time, or if we are in analysis mode.
- int time[COLOR_NB], inc[COLOR_NB], movestogo, depth, nodes, movetime, mate, infinite, ponder;
-};
+struct LimitsType {
+ LimitsType() { // Init explicitly due to broken value-initialization of non POD in MSVC
+ time[WHITE] = time[BLACK] = inc[WHITE] = inc[BLACK] = npmsec = movetime = TimePoint(0);
+ movestogo = depth = mate = perft = infinite = 0;
+ nodes = 0;
+ }
-/// The SignalsType struct stores volatile flags updated during the search
-/// typically in an async fashion, for instance to stop the search by the GUI.
+ bool use_time_management() const {
+ return time[WHITE] || time[BLACK];
+ }
-struct SignalsType {
- bool stopOnPonderhit, firstRootMove, stop, failedLowAtRoot;
+ std::vector<Move> searchmoves;
+ TimePoint time[COLOR_NB], inc[COLOR_NB], npmsec, movetime, startTime;
+ int movestogo, depth, mate, perft, infinite;
+ int64_t nodes;
};
-typedef std::auto_ptr<std::stack<StateInfo> > StateStackPtr;
-
-extern volatile SignalsType Signals;
extern LimitsType Limits;
-extern std::vector<RootMove> RootMoves;
-extern Position RootPos;
-extern Color RootColor;
-extern Time::point SearchTime;
-extern StateStackPtr SetupStates;
-extern void init();
-extern size_t perft(Position& pos, Depth depth);
-extern void think();
+void init();
+void clear();
} // namespace Search
-#endif // !defined(SEARCH_H_INCLUDED)
+} // namespace Stockfish
+
+#endif // #ifndef SEARCH_H_INCLUDED