/*
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) 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
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
-#if !defined MOVEPICK_H_INCLUDED
+#ifndef MOVEPICK_H_INCLUDED
#define MOVEPICK_H_INCLUDED
#include <algorithm> // For std::max
-#include <cstring> // For memset
+#include <cstring> // For std::memset
#include "movegen.h"
#include "position.h"
/// The Stats struct stores moves statistics. According to the template parameter
-/// the class can store both History and Gains type statistics. History records
-/// how often different moves have been successful or unsuccessful during the
-/// current search and is used for reduction and move ordering decisions. Gains
-/// records the move's best evaluation gain from one ply to the next and is used
-/// for pruning decisions. Entries are stored according only to moving piece and
-/// destination square, in particular two moves with different origin but same
-/// destination and same piece will be considered identical.
-template<bool Gain>
+/// the class can store History and Countermoves. History records how often
+/// different moves have been successful or unsuccessful during the current search
+/// and is used for reduction and move ordering decisions.
+/// Countermoves store the move that refute a previous one. Entries are stored
+/// using only the moving piece and destination square, hence two moves with
+/// different origin but same destination and piece will be considered identical.
+template<typename T, bool CM = false>
struct Stats {
- static const Value Max = Value(2000);
+ static const Value Max = Value(1 << 28);
- const Value* operator[](Piece p) const { return &table[p][0]; }
- void clear() { memset(table, 0, sizeof(table)); }
+ const T* operator[](Piece pc) const { return table[pc]; }
+ T* operator[](Piece pc) { return table[pc]; }
+ void clear() { std::memset(table, 0, sizeof(table)); }
- void update(Piece p, Square to, Value v) {
+ void update(Piece pc, Square to, Move m) { table[pc][to] = m; }
- if (Gain)
- table[p][to] = std::max(v, table[p][to] - 1);
+ void update(Piece pc, Square to, Value v) {
- else if (abs(table[p][to] + v) < Max)
- table[p][to] += v;
+ if (abs(int(v)) >= 324)
+ return;
+
+ table[pc][to] -= table[pc][to] * abs(int(v)) / (CM ? 936 : 324);
+ table[pc][to] += int(v) * 32;
}
private:
- Value table[PIECE_NB][SQUARE_NB];
+ T table[PIECE_NB][SQUARE_NB];
};
-typedef Stats<false> History;
-typedef Stats<true> Gains;
+typedef Stats<Move> MoveStats;
+typedef Stats<Value, false> HistoryStats;
+typedef Stats<Value, true> CounterMoveStats;
+typedef Stats<CounterMoveStats> CounterMoveHistoryStats;
-// FIXME: Document me
-struct RefutationTable {
+struct FromToStats {
- void clear() { memset(table, 0, sizeof(table)); }
- void update(Piece p, Square to, Move m) { table[p][to] = m; }
- Move get(Piece p, Square to) const { return table[p][to]; }
+ Value get(Color c, Move m) const { return table[c][from_sq(m)][to_sq(m)]; }
+ void clear() { std::memset(table, 0, sizeof(table)); }
-private:
- Move table[PIECE_NB][SQUARE_NB]; // Mapping: "move A" -> "move B which refutes move A"
+ void update(Color c, Move m, Value v)
+ {
+ if (abs(int(v)) >= 324)
+ return;
+
+ Square f = from_sq(m);
+ Square t = to_sq(m);
+
+ table[c][f][t] -= table[c][f][t] * abs(int(v)) / 324;
+ table[c][f][t] += int(v) * 32;
+ }
+private:
+ Value table[COLOR_NB][SQUARE_NB][SQUARE_NB];
};
/// MovePicker class is used to pick one pseudo legal move at a time from the
/// to get a cut-off first.
class MovePicker {
+public:
+ MovePicker(const MovePicker&) = delete;
+ MovePicker& operator=(const MovePicker&) = delete;
- MovePicker& operator=(const MovePicker&); // Silence a warning under MSVC
+ MovePicker(const Position&, Move, Value);
+ MovePicker(const Position&, Move, Depth, Square);
+ MovePicker(const Position&, Move, Depth, Search::Stack*);
-public:
- MovePicker(const Position&, Move, Depth, const History&, Search::Stack*, Move, Value);
- MovePicker(const Position&, Move, Depth, const History&, Square);
- MovePicker(const Position&, Move, const History&, PieceType);
- template<bool SpNode> Move next_move();
+ Move next_move();
+ int see_sign() const;
private:
template<GenType> void score();
- void generate_next();
+ void generate_next_stage();
+ ExtMove* begin() { return moves; }
+ ExtMove* end() { return endMoves; }
const Position& pos;
- const History& Hist;
- Search::Stack* ss;
+ const Search::Stack* ss;
+ Move countermove;
Depth depth;
Move ttMove;
- MoveStack killers[3];
+ ExtMove killers[3];
Square recaptureSquare;
- int captureThreshold, phase;
- MoveStack *cur, *end, *endQuiets, *endBadCaptures;
- MoveStack moves[MAX_MOVES];
+ Value threshold;
+ int stage;
+ ExtMove* endBadCaptures = moves + MAX_MOVES - 1;
+ ExtMove moves[MAX_MOVES], *cur = moves, *endMoves = moves;
};
-#endif // !defined(MOVEPICK_H_INCLUDED)
+#endif // #ifndef MOVEPICK_H_INCLUDED