X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmovepick.h;h=33c4b08602bbd78ecdfd1a978ef287a43f713ec5;hp=db9439f715ed1860718f712d9afb855987117fd9;hb=b8c00efa2767ebf74545d2ba4bd344ef7c963319;hpb=4bc11984fc5a148ee8f1b55d6ac47c4a397cc8b8 diff --git a/src/movepick.h b/src/movepick.h index db9439f7..33c4b086 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) 2015-2017 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + Copyright (C) 2015-2020 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 @@ -23,95 +23,91 @@ #include #include +#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> { +/// 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 { - void fill(const T& v) { - T* p = &(*this)[0][0]; - std::fill(p, p + sizeof(*this) / sizeof(*p), v); - } + T entry; - void update(T& entry, int bonus, const int D) { +public: + void operator=(const T& v) { entry = v; } + T* operator&() { return &entry; } + T* operator->() { return &entry; } + operator const T&() const { return entry; } - assert(abs(bonus) <= D); // Ensure range is [-32 * D, 32 * D] - assert(abs(32 * D) < (std::numeric_limits::max)()); // Ensure we don't overflow + void operator<<(int bonus) { + assert(abs(bonus) <= D); // Ensure range is [-D, D] + static_assert(D <= std::numeric_limits::max(), "D overflows T"); - entry += bonus * 32 - entry * abs(bonus) / D; + entry += bonus - entry * abs(bonus) / D; - assert(abs(entry) <= 32 * D); + assert(abs(entry) <= D); } }; -/// StatCubes is a generic 3-dimensional array used to store various statistics -template -struct StatCubes : public std::array, Size2>, Size1> { +/// 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) { - T* p = &(*this)[0][0][0]; - std::fill(p, p + sizeof(*this) / sizeof(*p), v); - } - - void update(T& entry, int bonus, const int D, const int W) { - assert(abs(bonus) <= D); // Ensure range is [-W * D, W * D] - assert(abs(W * D) < (std::numeric_limits::max)()); // Ensure we don't overflow + // For standard-layout 'this' points to first struct member + assert(std::is_standard_layout::value); - entry += bonus * W - entry * abs(bonus) / D; - - assert(abs(entry) <= W * D); + typedef StatsEntry entry; + entry* p = reinterpret_cast(this); + std::fill(p, p + sizeof(*this) / sizeof(entry), v); } }; -/// 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; - -/// PieceToBoards are addressed by a move's [piece][to] information -typedef StatBoards PieceToBoards; +template +struct Stats : public std::array, Size> {}; -/// CapturePieceToBoards are addressed by a move's [piece][to][captured piece type] information -typedef StatCubes CapturePieceToBoards; +/// In stats table, D=0 means that the template parameter is not used +enum StatsParams { NOT_USED = 0 }; +enum StatsType { NoCaptures, Captures }; /// 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 { - - void update(Color c, Move m, int bonus) { - StatBoards::update((*this)[c][from_to(m)], bonus, 324); - } -}; +/// 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; -/// PieceToHistory is like ButterflyHistory, but is based on PieceToBoards -struct PieceToHistory : public PieceToBoards { +/// LowPlyHistory at higher depths records successful quiet moves on plies 0 to 3 +/// and quiet moves which are/were in the PV (ttPv) +/// It get cleared with each new search and get filled during iterative deepening +constexpr int MAX_LPH = 4; +typedef Stats LowPlyHistory; - void update(Piece pc, Square to, int bonus) { - StatBoards::update((*this)[pc][to], bonus, 936); - } -}; - -/// CapturePieceToHistory is like PieceToHistory, but is based on CapturePieceToBoards -struct CapturePieceToHistory : public CapturePieceToBoards { +/// CounterMoveHistory stores counter moves indexed by [piece][to] of the previous +/// move, see www.chessprogramming.org/Countermove_Heuristic +typedef Stats CounterMoveHistory; - void update(Piece pc, Square to, PieceType captured, int bonus) { - StatCubes::update((*this)[pc][to][captured], bonus, 324, 2); - } -}; +/// CapturePieceToHistory is addressed by a move's [piece][to][captured piece type] +typedef Stats CapturePieceToHistory; -/// CounterMoveHistory stores counter moves indexed by [piece][to] of the previous -/// move, see chessprogramming.wikispaces.com/Countermove+Heuristic -typedef StatBoards CounterMoveHistory; +/// PieceToHistory is like ButterflyHistory but is addressed by a move's [piece][to] +typedef Stats PieceToHistory; -/// 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; +/// 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; /// MovePicker class is used to pick one pseudo legal move at a time from the @@ -120,31 +116,45 @@ typedef StatBoards ContinuationHistory; /// 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 }; + 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*, Square); - MovePicker(const Position&, Move, Depth, const ButterflyHistory*, const CapturePieceToHistory*, const PieceToHistory**, Move, Move*); + MovePicker(const Position&, Move, Depth, const ButterflyHistory*, + const CapturePieceToHistory*, + const PieceToHistory**, + Square); + MovePicker(const Position&, Move, Depth, const ButterflyHistory*, + const LowPlyHistory*, + const CapturePieceToHistory*, + const PieceToHistory**, + Move, + Move*, + int); Move next_move(bool skipQuiets = false); private: + template Move select(Pred); template void score(); ExtMove* begin() { return cur; } ExtMove* end() { return endMoves; } const Position& pos; const ButterflyHistory* mainHistory; + const LowPlyHistory* lowPlyHistory; const CapturePieceToHistory* captureHistory; - const PieceToHistory** contHistory; - Move ttMove, countermove, killers[2]; - ExtMove *cur, *endMoves, *endBadCaptures; + const PieceToHistory** continuationHistory; + Move ttMove; + ExtMove refutations[3], *cur, *endMoves, *endBadCaptures; int stage; Square recaptureSquare; Value threshold; Depth depth; + int ply; ExtMove moves[MAX_MOVES]; };