X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmovepick.h;h=d6451f6bf0ad4575212802a1708c4792a2ce5887;hp=6fbd8be1387fc46ce277a03f29a1f2442171ac19;hb=9001f55147fa304223623a6de0025ffe79f5fcc3;hpb=3ab3e55bb5faf57aec864f3bb7268601c11d72be diff --git a/src/movepick.h b/src/movepick.h index 6fbd8be1..d6451f6b 100644 --- a/src/movepick.h +++ b/src/movepick.h @@ -2,7 +2,7 @@ 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 + Copyright (C) 2015-2017 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 @@ -21,68 +21,70 @@ #ifndef MOVEPICK_H_INCLUDED #define MOVEPICK_H_INCLUDED -#include // For std::max -#include // For std::memset +#include #include "movegen.h" #include "position.h" #include "types.h" +/// StatBoards is a generic 2-dimensional array used to store various statistics +template +struct StatBoards : public std::array, Size1> { -/// The Stats struct stores moves statistics. According to the template parameter -/// 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 -struct Stats { + void fill(const T& v) { + T* p = &(*this)[0][0]; + std::fill(p, p + sizeof(*this) / sizeof(*p), v); + } - static const Value Max = Value(1 << 28); + void update(T& entry, int bonus, const int D) { - 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) { + assert([&]{ + int v = entry + bonus * 32 - entry * abs(bonus) / D; + return INT16_MIN < v && v < INT16_MAX; + }()); - if (abs(int(v)) >= 324) - return; + assert(abs(bonus) <= D); // Consistency check for below formula - table[pc][to] -= table[pc][to] * abs(int(v)) / (CM ? 936 : 324); - table[pc][to] += int(v) * 32; - } + entry += bonus * 32 - entry * abs(bonus) / D; -private: - T table[PIECE_NB][SQUARE_NB]; + assert(abs(entry) <= 32 * D); + } }; -typedef Stats MoveStats; -typedef Stats HistoryStats; -typedef Stats CounterMoveStats; -typedef Stats CounterMoveHistoryStats; +/// ButterflyBoards are 2 tables (one for each color) indexed by the move's from +/// and to squares, see chessprogramming.wikispaces.com/Butterfly+Boards +typedef StatBoards ButterflyBoards; -struct FromToStats { +/// PieceToBoards are addressed by a move's [piece][to] information +typedef StatBoards PieceToBoards; - 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) { +/// ButterflyHistory records how often quiet moves have been successful or +/// unsuccessful during the current search, and is used for reduction and move +/// ordering decisions. It uses ButterflyBoards as backing store. +struct ButterflyHistory : public ButterflyBoards { - if (abs(int(v)) >= 324) - return; + void update(Color c, Move m, int bonus) { + StatBoards::update((*this)[c][from_to(m)], bonus, 324); + } +}; - Square from = from_sq(m); - Square to = to_sq(m); +/// PieceToHistory is like ButterflyHistory, but is based on PieceToBoards +struct PieceToHistory : public PieceToBoards { - table[c][from][to] -= table[c][from][to] * abs(int(v)) / 324; - table[c][from][to] += int(v) * 32; + void update(Piece pc, Square to, int bonus) { + StatBoards::update((*this)[pc][to], bonus, 936); } - -private: - Value table[COLOR_NB][SQUARE_NB][SQUARE_NB]; }; +/// CounterMoveHistory stores counter moves indexed by [piece][to] of the previous +/// move, see chessprogramming.wikispaces.com/Countermove+Heuristic +typedef StatBoards CounterMoveHistory; + +/// ContinuationHistory is the history of a given pair of moves, usually the +/// current one given a previous one. History table is based on PieceToBoards +/// instead of ButterflyBoards. +typedef StatBoards ContinuationHistory; + /// 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 @@ -90,18 +92,15 @@ private: /// 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 { public: 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*); - - Move next_move(); + MovePicker(const Position&, Move, Depth, const ButterflyHistory*, const PieceToHistory**, Square); + MovePicker(const Position&, Move, Depth, const ButterflyHistory*, const PieceToHistory**, Move, Move*); + Move next_move(bool skipQuiets = false); private: template void score(); @@ -109,14 +108,14 @@ private: ExtMove* end() { return endMoves; } const Position& pos; - const Search::Stack* ss; - Move countermove; - Depth depth; - Move ttMove; + const ButterflyHistory* mainHistory; + const PieceToHistory** contHistory; + Move ttMove, countermove, killers[2]; + ExtMove *cur, *endMoves, *endBadCaptures; + int stage; Square recaptureSquare; Value threshold; - int stage; - ExtMove *cur, *endMoves, *endBadCaptures; + Depth depth; ExtMove moves[MAX_MOVES]; };