WebSVN – Games.Chess Giants – Diff – /engine-stockfish/movepick.h

   Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
-  Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+  Copyright (C) 2015-2019 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
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.
 #ifndef MOVEPICK_H_INCLUDED
 #define MOVEPICK_H_INCLUDED
 #include <array>
 #include <limits>
+#include <type_traits>
 #include "movegen.h"
 #include "position.h"
 #include "types.h"
-/// StatBoards is a generic 2-dimensional array used to store various statistics
+/// 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
-template<int Size1, int Size2, typename T = int16_t>
+/// to directly call history update operator<<() on the entry so to use stats
-struct StatBoards : public std::array<std::array<T, Size2>, Size1> {
+/// tables at caller sites as simple multi-dim arrays.
+template<typename T, int D>
+class StatsEntry {
-  void fill(const T& v) {
-    T* p = &(*this)[0][0];
-    std::fill(p, p + sizeof(*this) / sizeof(*p), v);
-  }
+  T entry;
+public:
-  void update(T& entry, int bonus, const int D) {
+  void operator=(const T& v) { entry = v; }
+  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 [-32 * D, 32 * D]
+    assert(abs(bonus) <= D); // Ensure range is [-D, D]
-    assert(abs(32 * D) < (std::numeric_limits<T>::max)()); // Ensure we don't overflow
+    static_assert(D <= std::numeric_limits<T>::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
+/// 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<int Size1, int Size2, int Size3, typename T = int16_t>
+template <typename T, int D, int Size, int... Sizes>
-struct StatCubes : public std::array<std::array<std::array<T, Size3>, Size2>, Size1> {
+struct Stats : public std::array<Stats<T, D, Sizes...>, Size>
+{
+  typedef Stats<T, D, Size, Sizes...> 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<T>::max)()); // Ensure we don't overflow
+    // For standard-layout 'this' points to first struct member
-    entry += bonus * W - entry * abs(bonus) / D;
+    assert(std::is_standard_layout<stats>::value);
-    assert(abs(entry) <= W * D);
+    typedef StatsEntry<T, D> entry;
+    entry* p = reinterpret_cast<entry*>(this);
+    std::fill(p, p + sizeof(*this) / sizeof(entry), v);
+  }
 };
-/// ButterflyBoards are 2 tables (one for each color) indexed by the move's from
+template <typename T, int D, int Size>
-/// and to squares, see chessprogramming.wikispaces.com/Butterfly+Boards
-typedef StatBoards<COLOR_NB, int(SQUARE_NB) * int(SQUARE_NB)> ButterflyBoards;
+struct Stats<T, D, Size> : public std::array<StatsEntry<T, D>, Size> {};
-/// PieceToBoards are addressed by a move's [piece][to] information
+/// In stats table, D=0 means that the template parameter is not used
-typedef StatBoards<PIECE_NB, SQUARE_NB> PieceToBoards;
+enum StatsParams { NOT_USED = 0 };
-/// CapturePieceToBoards are addressed by a move's [piece][to][captured piece type] information
-typedef StatCubes<PIECE_NB, SQUARE_NB, PIECE_TYPE_NB> CapturePieceToBoards;
 /// 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.
+/// ordering decisions. It uses 2 tables (one for each color) indexed by
-struct ButterflyHistory : public ButterflyBoards {
+/// the move's from and to squares, see chessprogramming.wikispaces.com/Butterfly+Boards
+typedef Stats<int16_t, 10692, COLOR_NB, int(SQUARE_NB) * int(SQUARE_NB)> ButterflyHistory;
+/// CounterMoveHistory stores counter moves indexed by [piece][to] of the previous
-  void update(Color c, Move m, int bonus) {
+/// move, see chessprogramming.wikispaces.com/Countermove+Heuristic
-    StatBoards::update((*this)[c][from_to(m)], bonus, 324);
+typedef Stats<Move, NOT_USED, PIECE_NB, SQUARE_NB> CounterMoveHistory;
-  }
-};
-/// PieceToHistory is like ButterflyHistory, but is based on PieceToBoards
+/// CapturePieceToHistory is addressed by a move's [piece][to][captured piece type]
-struct PieceToHistory : public PieceToBoards {
+typedef Stats<int16_t, 10692, PIECE_NB, SQUARE_NB, PIECE_TYPE_NB> CapturePieceToHistory;
-  void update(Piece pc, Square to, int bonus) {
+/// PieceToHistory is like ButterflyHistory but is addressed by a move's [piece][to]
-    StatBoards::update((*this)[pc][to], bonus, 936);
+typedef Stats<int16_t, 29952, PIECE_NB, SQUARE_NB> PieceToHistory;
-  }
-};
-/// CapturePieceToHistory is like PieceToHistory, but is based on CapturePieceToBoards
-struct CapturePieceToHistory : public CapturePieceToBoards {
-  void update(Piece pc, Square to, PieceType captured, int bonus) {
-    StatCubes::update((*this)[pc][to][captured], bonus, 324, 2);
-  }
-};
-/// CounterMoveHistory stores counter moves indexed by [piece][to] of the previous
-/// move, see chessprogramming.wikispaces.com/Countermove+Heuristic
-typedef StatBoards<PIECE_NB, SQUARE_NB, Move> CounterMoveHistory;
-/// ContinuationHistory is the history of a given pair of moves, usually the
+/// ContinuationHistory is the combined history of a given pair of moves, usually
-/// current one given a previous one. History table is based on PieceToBoards
+/// the current one given a previous one. The nested history table is based on
-/// instead of ButterflyBoards.
+/// PieceToHistory instead of ButterflyBoards.
-typedef StatBoards<PIECE_NB, SQUARE_NB, PieceToHistory> ContinuationHistory;
+typedef Stats<PieceToHistory, NOT_USED, PIECE_NB, SQUARE_NB> 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
 /// 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 };
 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**,
+                                           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**,
+                                           Move,
+                                           Move*);
   Move next_move(bool skipQuiets = false);
 private:
+  template<PickType T, typename Pred> Move select(Pred);
   template<GenType> void score();
   ExtMove* begin() { return cur; }
   ExtMove* end() { return endMoves; }
   const Position& pos;
   const ButterflyHistory* mainHistory;
   const CapturePieceToHistory* captureHistory;
-  const PieceToHistory** contHistory;
+  const PieceToHistory** continuationHistory;
-  Move ttMove, countermove, killers[2];
+  Move ttMove;
-  ExtMove *cur, *endMoves, *endBadCaptures;
+  ExtMove refutations[3], *cur, *endMoves, *endBadCaptures;
   int stage;
+  Move move;
   Square recaptureSquare;
   Value threshold;
   Depth depth;
   ExtMove moves[MAX_MOVES];
 };

Subversion Repositories Games.Chess Giants

Games.Chess Giants/engine-stockfish/movepick.h – Rev 169 → 185