X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmovepick.h;h=33c4b08602bbd78ecdfd1a978ef287a43f713ec5;hp=d9f0457a122fad9a6c9206cf79f371371d107594;hb=b8c00efa2767ebf74545d2ba4bd344ef7c963319;hpb=f35e52f030af837ed8a89eecd67a6f746ee2e897 diff --git a/src/movepick.h b/src/movepick.h index d9f0457a..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) 2015-2018 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 @@ -33,74 +33,81 @@ /// 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 +template class StatsEntry { - static const bool IsInt = std::is_integral::value; - typedef typename std::conditional::type TT; - T entry; public: - T* get() { return &entry; } void operator=(const T& v) { entry = v; } - operator TT() const { return entry; } + T* operator&() { return &entry; } + T* operator->() { return &entry; } + operator const T&() const { return entry; } void operator<<(int bonus) { + assert(abs(bonus) <= D); // Ensure range is [-D, D] + static_assert(D <= std::numeric_limits::max(), "D overflows T"); - assert(abs(bonus) <= D); // Ensure range is [-W * D, W * D] - assert(abs(W * D) < std::numeric_limits::max()); // Ensure we don't overflow - - entry += bonus * W - entry * abs(bonus) / D; + entry += bonus - entry * abs(bonus) / D; - assert(abs(entry) <= W * D); + assert(abs(entry) <= D); } }; /// Stats is a generic N-dimensional array used to store various statistics. -/// The first template T parameter is the base type of the array, the W parameter -/// is the weight applied to the bonuses when we update values with the << operator, -/// the D parameter limits the range of updates (range is [-W * D, W * D]), and -/// the last parameters (Size and Sizes) encode the dimensions of the array. -template -struct Stats : public std::array, Size> +/// 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> { - T* get() { return this->at(0).get(); } + typedef Stats stats; void fill(const T& v) { - T* p = get(); - std::fill(p, p + sizeof(*this) / sizeof(*p), 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); } }; -template -struct Stats : public std::array, Size> { - T* get() { return this->at(0).get(); } -}; +template +struct Stats : public std::array, Size> {}; -/// Different tables use different W/D parameter, name them to ease readibility -enum StatsParams { W2 = 2, W32 = 32, D324 = 324, D936 = 936, NOT_USED = 0 }; +/// 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 2 tables (one for each color) indexed by -/// the move's from and to squares, see chessprogramming.wikispaces.com/Butterfly+Boards -typedef Stats ButterflyHistory; +/// the move's from and to squares, see www.chessprogramming.org/Butterfly_Boards +typedef Stats ButterflyHistory; + +/// 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; /// CounterMoveHistory stores counter moves indexed by [piece][to] of the previous -/// move, see chessprogramming.wikispaces.com/Countermove+Heuristic -typedef Stats CounterMoveHistory; +/// move, see www.chessprogramming.org/Countermove_Heuristic +typedef Stats CounterMoveHistory; /// CapturePieceToHistory is addressed by a move's [piece][to][captured piece type] -typedef Stats CapturePieceToHistory; +typedef Stats CapturePieceToHistory; /// PieceToHistory is like ButterflyHistory but is addressed by a move's [piece][to] -typedef Stats PieceToHistory; +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; +typedef Stats ContinuationHistory; /// MovePicker class is used to pick one pseudo legal move at a time from the @@ -109,31 +116,45 @@ typedef Stats ContinuationHi /// 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]; };