/*
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
#include "movegen.h"
#include "position.h"
-#include "search.h"
#include "types.h"
/// The Stats struct stores moves statistics. According to the template parameter
-/// the class can store History, Gains and Countermoves. History records how often
+/// 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. Gains records the move's
-/// best evaluation gain from one ply to the next and is used for pruning decisions.
+/// and is used for reduction and move ordering decisions.
/// Countermoves store the move that refute a previous one. Entries are stored
-/// according only to moving piece and destination square, hence two moves with
+/// using only the moving piece and destination square, hence two moves with
/// different origin but same destination and piece will be considered identical.
-template<bool Gain, typename T>
+template<typename T, bool CM = false>
struct Stats {
- static const Value Max = Value(2000);
+ static const Value Max = Value(1 << 28);
- const T* operator[](Piece p) const { return table[p]; }
+ 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 pc, Square to, Move m) { table[pc][to] = m; }
+ void update(Piece pc, Square to, Value v) {
- void update(Piece p, Square to, Move m) {
-
- if (m == table[p][to].first)
+ if (abs(int(v)) >= 324)
return;
- table[p][to].second = table[p][to].first;
- table[p][to].first = m;
+ table[pc][to] -= table[pc][to] * abs(int(v)) / (CM ? 936 : 324);
+ table[pc][to] += int(v) * 32;
}
- void update(Piece p, Square to, Value v) {
+private:
+ T table[PIECE_NB][SQUARE_NB];
+};
+
+typedef Stats<Move> MoveStats;
+typedef Stats<Value, false> HistoryStats;
+typedef Stats<Value, true> CounterMoveStats;
+typedef Stats<CounterMoveStats> CounterMoveHistoryStats;
+
+struct FromToStats {
- if (Gain)
- table[p][to] = std::max(v, table[p][to] - 1);
+ Value get(Color c, Move m) const { return table[c][from_sq(m)][to_sq(m)]; }
+ void clear() { std::memset(table, 0, sizeof(table)); }
+ void update(Color c, Move m, Value v) {
- else if (abs(table[p][to] + v) < Max)
- table[p][to] += v;
+ if (abs(int(v)) >= 324)
+ return;
+
+ Square from = from_sq(m);
+ Square to = to_sq(m);
+
+ table[c][from][to] -= table[c][from][to] * abs(int(v)) / 324;
+ table[c][from][to] += int(v) * 32;
}
private:
- T table[PIECE_NB][SQUARE_NB];
+ Value table[COLOR_NB][SQUARE_NB][SQUARE_NB];
};
-typedef Stats< true, Value> GainsStats;
-typedef Stats<false, Value> HistoryStats;
-typedef Stats<false, std::pair<Move, Move> > CountermovesStats;
-
/// MovePicker class is used to pick one pseudo legal move at a time from the
/// current position. The most important method is next_move(), which returns a
/// when MOVE_NONE is returned. In order to improve the efficiency of the alpha
/// beta algorithm, MovePicker attempts to return the moves which are most likely
/// to get a cut-off first.
+namespace Search { struct Stack; }
class MovePicker {
-
- MovePicker& operator=(const MovePicker&); // Silence a warning under MSVC
-
public:
- MovePicker(const Position&, Move, Depth, const HistoryStats&, Square);
- MovePicker(const Position&, Move, const HistoryStats&, PieceType);
- MovePicker(const Position&, Move, Depth, const HistoryStats&, Move*, Search::Stack*);
+ MovePicker(const MovePicker&) = delete;
+ MovePicker& operator=(const MovePicker&) = delete;
+
+ MovePicker(const Position&, Move, Value);
+ MovePicker(const Position&, Move, Depth, Square);
+ MovePicker(const Position&, Move, Depth, Search::Stack*);
- template<bool SpNode> Move next_move();
+ Move next_move();
private:
template<GenType> void score();
- void generate_next();
+ ExtMove* begin() { return cur; }
+ ExtMove* end() { return endMoves; }
const Position& pos;
- const HistoryStats& history;
- Search::Stack* ss;
- Move* countermoves;
+ const Search::Stack* ss;
+ Move countermove;
Depth depth;
Move ttMove;
- ExtMove killers[4];
Square recaptureSquare;
- int captureThreshold, stage;
- ExtMove *cur, *end, *endQuiets, *endBadCaptures;
+ Value threshold;
+ int stage;
+ ExtMove *cur, *endMoves, *endBadCaptures;
ExtMove moves[MAX_MOVES];
};