X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmovepick.h;h=d9ecba99d8e3043f47c7c7981b69d37de9b386dc;hp=a5ecb0662015edf7cb01d98dd506327e2031405b;hb=5446e6f408f2ed7fa281dbe0097c46674d193260;hpb=595a90dfd0cd393a8805f4f51cf5c5d8b264c121 diff --git a/src/movepick.h b/src/movepick.h index a5ecb066..d9ecba99 100644 --- a/src/movepick.h +++ b/src/movepick.h @@ -1,7 +1,8 @@ /* Stockfish, a UCI chess playing engine derived from Glaurung 2.1 Copyright (C) 2004-2008 Tord Romstad (Glaurung author) - Copyright (C) 2008-2009 Marco Costalba + Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2015-2019 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 @@ -17,95 +18,135 @@ along with this program. If not, see . */ - -#if !defined MOVEPICK_H_INCLUDED +#ifndef MOVEPICK_H_INCLUDED #define MOVEPICK_H_INCLUDED -//// -//// Includes -//// +#include +#include +#include -#include "depth.h" -#include "history.h" -#include "lock.h" +#include "movegen.h" #include "position.h" +#include "types.h" + +/// StatsEntry stores the stat table value. It is usually a number but could +/// be a move or even a nested history. We use a class instead of naked value +/// to directly call history update operator<<() on the entry so to use stats +/// tables at caller sites as simple multi-dim arrays. +template +class StatsEntry { + T entry; -//// -//// Types -//// +public: + void operator=(const T& v) { entry = v; } + T* operator&() { return &entry; } + T* operator->() { return &entry; } + operator const T&() const { return entry; } -struct SearchStack; + void operator<<(int bonus) { + assert(abs(bonus) <= D); // Ensure range is [-D, D] + static_assert(D <= std::numeric_limits::max(), "D overflows T"); -enum MovegenPhase { - PH_TT_MOVES, // Transposition table move and mate killer - PH_GOOD_CAPTURES, // Queen promotions and captures with SEE values >= 0 - PH_KILLERS, // Killer moves from the current ply - PH_NONCAPTURES, // Non-captures and underpromotions - PH_BAD_CAPTURES, // Queen promotions and captures with SEE values < 0 - PH_EVASIONS, // Check evasions - PH_QCAPTURES, // Captures in quiescence search - PH_QCHECKS, // Non-capture checks in quiescence search - PH_STOP + entry += bonus - entry * abs(bonus) / D; + + assert(abs(entry) <= D); + } }; -typedef uint8_t MovegenPhaseT; +/// Stats is a generic N-dimensional array used to store various statistics. +/// The first template parameter T is the base type of the array, the second +/// template parameter D limits the range of updates in [-D, D] when we update +/// values with the << operator, while the last parameters (Size and Sizes) +/// encode the dimensions of the array. +template +struct Stats : public std::array, Size> +{ + typedef Stats stats; + + void fill(const T& v) { + + // For standard-layout 'this' points to first struct member + assert(std::is_standard_layout::value); + + typedef StatsEntry entry; + entry* p = reinterpret_cast(this); + std::fill(p, p + sizeof(*this) / sizeof(entry), v); + } +}; -/// MovePicker is a class which is used to pick one legal move at a time from -/// the current position. It is initialized with a Position object and a few -/// moves we have reason to believe are good. The most important method is -/// MovePicker::pick_next_move(), which returns a new legal move each time it -/// is called, until there are no legal moves left, 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 be strongest first. +template +struct Stats : public std::array, Size> {}; -class MovePicker { +/// In stats table, D=0 means that the template parameter is not used +enum StatsParams { NOT_USED = 0 }; - MovePicker& operator=(const MovePicker&); // silence a warning under MSVC -public: - MovePicker(const Position& p, Move ttm, Depth d, const History& h, SearchStack* ss = NULL); - Move get_next_move(); - Move get_next_move(Lock& lock); - int number_of_moves() const; - Bitboard discovered_check_candidates() const; +/// 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 2 tables (one for each color) indexed by +/// the move's from and to squares, see www.chessprogramming.org/Butterfly_Boards +typedef Stats ButterflyHistory; -private: - void score_captures(); - void score_noncaptures(); - void score_evasions(); - Move pick_move_from_list(); +/// CounterMoveHistory stores counter moves indexed by [piece][to] of the previous +/// move, see www.chessprogramming.org/Countermove_Heuristic +typedef Stats CounterMoveHistory; - const Position& pos; - const History& H; - Move ttMoves[2], killers[2]; - const MovegenPhaseT* phasePtr; - int movesPicked, numOfMoves, numOfBadCaptures; - bool finished; - Bitboard dc, pinned; - MoveStack moves[256], badCaptures[64]; -}; +/// CapturePieceToHistory is addressed by a move's [piece][to][captured piece type] +typedef Stats CapturePieceToHistory; + +/// PieceToHistory is like ButterflyHistory but is addressed by a move's [piece][to] +typedef Stats PieceToHistory; +/// ContinuationHistory is the combined history of a given pair of moves, usually +/// the current one given a previous one. The nested history table is based on +/// PieceToHistory instead of ButterflyBoards. +typedef Stats ContinuationHistory; -//// -//// Inline functions -//// -/// MovePicker::number_of_moves() simply returns the numOfMoves member -/// variable. It is intended to be used in positions where the side to move -/// is in check, for detecting checkmates or situations where there is only -/// a single reply to check. +/// 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 +/// new pseudo legal move each time it is called, until there are no moves left, +/// 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. +class MovePicker { + + enum PickType { Next, Best }; -inline int MovePicker::number_of_moves() const { - return numOfMoves; -} +public: + MovePicker(const MovePicker&) = delete; + MovePicker& operator=(const MovePicker&) = delete; + MovePicker(const Position&, Move, Value, const CapturePieceToHistory*); + MovePicker(const Position&, Move, Depth, const ButterflyHistory*, + const CapturePieceToHistory*, + const PieceToHistory**, + Square); + MovePicker(const Position&, Move, Depth, const ButterflyHistory*, + const CapturePieceToHistory*, + const PieceToHistory**, + Move, + Move*); + Move next_move(bool skipQuiets = false); -/// MovePicker::discovered_check_candidates() returns a bitboard containing -/// all pieces which can possibly give discovered check. This bitboard is -/// computed by the constructor function. +private: + template Move select(Pred); + template void score(); + ExtMove* begin() { return cur; } + ExtMove* end() { return endMoves; } -inline Bitboard MovePicker::discovered_check_candidates() const { - return dc; -} + const Position& pos; + const ButterflyHistory* mainHistory; + const CapturePieceToHistory* captureHistory; + const PieceToHistory** continuationHistory; + Move ttMove; + ExtMove refutations[3], *cur, *endMoves, *endBadCaptures; + int stage; + Move move; + Square recaptureSquare; + Value threshold; + Depth depth; + ExtMove moves[MAX_MOVES]; +}; -#endif // !defined(MOVEPICK_H_INCLUDED) +#endif // #ifndef MOVEPICK_H_INCLUDED