refactor history code to history.h

bench 1283457

src/Makefile

@@ -57,7 +57,7 @@ SRCS = benchmark.cpp bitboard.cpp evaluate.cpp main.cpp \
 	search.cpp thread.cpp timeman.cpp tt.cpp uci.cpp ucioption.cpp tune.cpp syzygy/tbprobe.cpp \
 	nnue/nnue_misc.cpp nnue/features/half_ka_v2_hm.cpp nnue/network.cpp engine.cpp score.cpp memory.cpp
 
-HEADERS = benchmark.h bitboard.h evaluate.h misc.h movegen.h movepick.h \
+HEADERS = benchmark.h bitboard.h evaluate.h misc.h movegen.h movepick.h history.h \
 		nnue/nnue_misc.h nnue/features/half_ka_v2_hm.h nnue/layers/affine_transform.h \
 		nnue/layers/affine_transform_sparse_input.h nnue/layers/clipped_relu.h nnue/layers/simd.h \
 		nnue/layers/sqr_clipped_relu.h nnue/nnue_accumulator.h nnue/nnue_architecture.h \

src/history.h

@@ -0,0 +1,190 @@
+/*
+  Stockfish, a UCI chess playing engine derived from Glaurung 2.1
+  Copyright (C) 2004-2024 The Stockfish developers (see AUTHORS file)
+
+  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.
+
+  Stockfish is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef HISTORY_H_INCLUDED
+#define HISTORY_H_INCLUDED
+
+#include <algorithm>
+#include <array>
+#include <cassert>
+#include <cmath>
+#include <cstdint>
+#include <cstdlib>
+#include <limits>
+#include <type_traits>  // IWYU pragma: keep
+
+#include "position.h"
+
+namespace Stockfish {
+
+constexpr int PAWN_HISTORY_SIZE        = 512;    // has to be a power of 2
+constexpr int CORRECTION_HISTORY_SIZE  = 32768;  // has to be a power of 2
+constexpr int CORRECTION_HISTORY_LIMIT = 1024;
+constexpr int LOW_PLY_HISTORY_SIZE     = 4;
+
+static_assert((PAWN_HISTORY_SIZE & (PAWN_HISTORY_SIZE - 1)) == 0,
+              "PAWN_HISTORY_SIZE has to be a power of 2");
+
+static_assert((CORRECTION_HISTORY_SIZE & (CORRECTION_HISTORY_SIZE - 1)) == 0,
+              "CORRECTION_HISTORY_SIZE has to be a power of 2");
+
+enum PawnHistoryType {
+    Normal,
+    Correction
+};
+
+template<PawnHistoryType T = Normal>
+inline int pawn_structure_index(const Position& pos) {
+    return pos.pawn_key() & ((T == Normal ? PAWN_HISTORY_SIZE : CORRECTION_HISTORY_SIZE) - 1);
+}
+
+inline int material_index(const Position& pos) {
+    return pos.material_key() & (CORRECTION_HISTORY_SIZE - 1);
+}
+
+inline int major_piece_index(const Position& pos) {
+    return pos.major_piece_key() & (CORRECTION_HISTORY_SIZE - 1);
+}
+
+inline int minor_piece_index(const Position& pos) {
+    return pos.minor_piece_key() & (CORRECTION_HISTORY_SIZE - 1);
+}
+
+template<Color c>
+inline int non_pawn_index(const Position& pos) {
+    return pos.non_pawn_key(c) & (CORRECTION_HISTORY_SIZE - 1);
+}
+
+// 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 a 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<typename T, int D>
+class StatsEntry {
+
+    T entry;
+
+   public:
+    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) {
+        static_assert(D <= std::numeric_limits<T>::max(), "D overflows T");
+
+        // Make sure that bonus is in range [-D, D]
+        int clampedBonus = std::clamp(bonus, -D, D);
+        entry += clampedBonus - entry * std::abs(clampedBonus) / D;
+
+        assert(std::abs(entry) <= D);
+    }
+};
+
+// Stats is a generic N-dimensional array used to store various statistics.
+// The first template parameter T is the base type of the array, and 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<typename T, int D, int Size, int... Sizes>
+struct Stats: public std::array<Stats<T, D, Sizes...>, Size> {
+    using stats = Stats<T, D, Size, Sizes...>;
+
+    void fill(const T& v) {
+
+        // For standard-layout 'this' points to the first struct member
+        assert(std::is_standard_layout_v<stats>);
+
+        using entry = StatsEntry<T, D>;
+        entry* p    = reinterpret_cast<entry*>(this);
+        std::fill(p, p + sizeof(*this) / sizeof(entry), v);
+    }
+};
+
+template<typename T, int D, int Size>
+struct Stats<T, D, Size>: public std::array<StatsEntry<T, D>, Size> {};
+
+// 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 https://www.chessprogramming.org/Butterfly_Boards (~11 elo)
+using ButterflyHistory = Stats<int16_t, 7183, COLOR_NB, int(SQUARE_NB) * int(SQUARE_NB)>;
+
+// LowPlyHistory is adressed by play and move's from and to squares, used
+// to improve move ordering near the root
+using LowPlyHistory = Stats<int16_t, 7183, LOW_PLY_HISTORY_SIZE, int(SQUARE_NB) * int(SQUARE_NB)>;
+
+// CapturePieceToHistory is addressed by a move's [piece][to][captured piece type]
+using CapturePieceToHistory = Stats<int16_t, 10692, PIECE_NB, SQUARE_NB, PIECE_TYPE_NB>;
+
+// PieceToHistory is like ButterflyHistory but is addressed by a move's [piece][to]
+using PieceToHistory = Stats<int16_t, 29952, PIECE_NB, SQUARE_NB>;
+
+// 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.
+// (~63 elo)
+using ContinuationHistory = Stats<PieceToHistory, NOT_USED, PIECE_NB, SQUARE_NB>;
+
+// PawnHistory is addressed by the pawn structure and a move's [piece][to]
+using PawnHistory = Stats<int16_t, 8192, PAWN_HISTORY_SIZE, PIECE_NB, SQUARE_NB>;
+
+// Correction histories record differences between the static evaluation of
+// positions and their search score. It is used to improve the static evaluation
+// used by some search heuristics.
+// see https://www.chessprogramming.org/Static_Evaluation_Correction_History
+enum CorrHistType {
+    Pawn,          // By color and pawn structure
+    Material,      // By color and material configuration
+    Major,         // By color and positions of major pieces (Queen, Rook) and King
+    Minor,         // By color and positions of minor pieces (Knight, Bishop) and King
+    NonPawn,       // By color and non-pawn material positions
+    PieceTo,       // By [piece][to] move
+    Continuation,  // Combined history of move pairs
+};
+
+template<CorrHistType _>
+struct CorrHistTypedef {
+    using type = Stats<int16_t, CORRECTION_HISTORY_LIMIT, COLOR_NB, CORRECTION_HISTORY_SIZE>;
+};
+
+template<>
+struct CorrHistTypedef<PieceTo> {
+    using type = Stats<int16_t, CORRECTION_HISTORY_LIMIT, PIECE_NB, SQUARE_NB>;
+};
+
+template<>
+struct CorrHistTypedef<Continuation> {
+    using type = Stats<CorrHistTypedef<PieceTo>::type, NOT_USED, PIECE_NB, SQUARE_NB>;
+};
+
+template<CorrHistType T>
+using CorrectionHistory = typename CorrHistTypedef<T>::type;
+
+}  // namespace Stockfish
+
+#endif  // #ifndef HISTORY_H_INCLUDED

src/movepick.cpp

@@ -19,7 +19,9 @@
 #include "movepick.h"
 
 #include <algorithm>
+#include <array>
 #include <cassert>
+#include <limits>
 #include <utility>
 
 #include "bitboard.h"

src/movepick.h

@@ -19,173 +19,13 @@
 #ifndef MOVEPICK_H_INCLUDED
 #define MOVEPICK_H_INCLUDED
 
-#include <algorithm>
-#include <array>
-#include <cassert>
-#include <cmath>
-#include <cstdint>
-#include <cstdlib>
-#include <limits>
-#include <type_traits>  // IWYU pragma: keep
-
+#include "history.h"
 #include "movegen.h"
-#include "position.h"
 #include "types.h"
 
 namespace Stockfish {
 
-constexpr int PAWN_HISTORY_SIZE        = 512;    // has to be a power of 2
-constexpr int CORRECTION_HISTORY_SIZE  = 32768;  // has to be a power of 2
-constexpr int CORRECTION_HISTORY_LIMIT = 1024;
-constexpr int LOW_PLY_HISTORY_SIZE     = 4;
-
-static_assert((PAWN_HISTORY_SIZE & (PAWN_HISTORY_SIZE - 1)) == 0,
-              "PAWN_HISTORY_SIZE has to be a power of 2");
-
-static_assert((CORRECTION_HISTORY_SIZE & (CORRECTION_HISTORY_SIZE - 1)) == 0,
-              "CORRECTION_HISTORY_SIZE has to be a power of 2");
-
-enum PawnHistoryType {
-    Normal,
-    Correction
-};
-
-template<PawnHistoryType T = Normal>
-inline int pawn_structure_index(const Position& pos) {
-    return pos.pawn_key() & ((T == Normal ? PAWN_HISTORY_SIZE : CORRECTION_HISTORY_SIZE) - 1);
-}
-
-inline int material_index(const Position& pos) {
-    return pos.material_key() & (CORRECTION_HISTORY_SIZE - 1);
-}
-
-inline int major_piece_index(const Position& pos) {
-    return pos.major_piece_key() & (CORRECTION_HISTORY_SIZE - 1);
-}
-
-inline int minor_piece_index(const Position& pos) {
-    return pos.minor_piece_key() & (CORRECTION_HISTORY_SIZE - 1);
-}
-
-template<Color c>
-inline int non_pawn_index(const Position& pos) {
-    return pos.non_pawn_key(c) & (CORRECTION_HISTORY_SIZE - 1);
-}
-
-// 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 a 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<typename T, int D>
-class StatsEntry {
-
-    T entry;
-
-   public:
-    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) {
-        static_assert(D <= std::numeric_limits<T>::max(), "D overflows T");
-
-        // Make sure that bonus is in range [-D, D]
-        int clampedBonus = std::clamp(bonus, -D, D);
-        entry += clampedBonus - entry * std::abs(clampedBonus) / D;
-
-        assert(std::abs(entry) <= D);
-    }
-};
-
-// Stats is a generic N-dimensional array used to store various statistics.
-// The first template parameter T is the base type of the array, and 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<typename T, int D, int Size, int... Sizes>
-struct Stats: public std::array<Stats<T, D, Sizes...>, Size> {
-    using stats = Stats<T, D, Size, Sizes...>;
-
-    void fill(const T& v) {
-
-        // For standard-layout 'this' points to the first struct member
-        assert(std::is_standard_layout_v<stats>);
-
-        using entry = StatsEntry<T, D>;
-        entry* p    = reinterpret_cast<entry*>(this);
-        std::fill(p, p + sizeof(*this) / sizeof(entry), v);
-    }
-};
-
-template<typename T, int D, int Size>
-struct Stats<T, D, Size>: public std::array<StatsEntry<T, D>, Size> {};
-
-// 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 https://www.chessprogramming.org/Butterfly_Boards (~11 elo)
-using ButterflyHistory = Stats<int16_t, 7183, COLOR_NB, int(SQUARE_NB) * int(SQUARE_NB)>;
-
-// LowPlyHistory is adressed by play and move's from and to squares, used
-// to improve move ordering near the root
-using LowPlyHistory = Stats<int16_t, 7183, LOW_PLY_HISTORY_SIZE, int(SQUARE_NB) * int(SQUARE_NB)>;
-
-// CapturePieceToHistory is addressed by a move's [piece][to][captured piece type]
-using CapturePieceToHistory = Stats<int16_t, 10692, PIECE_NB, SQUARE_NB, PIECE_TYPE_NB>;
-
-// PieceToHistory is like ButterflyHistory but is addressed by a move's [piece][to]
-using PieceToHistory = Stats<int16_t, 29952, PIECE_NB, SQUARE_NB>;
-
-// 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.
-// (~63 elo)
-using ContinuationHistory = Stats<PieceToHistory, NOT_USED, PIECE_NB, SQUARE_NB>;
-
-// PawnHistory is addressed by the pawn structure and a move's [piece][to]
-using PawnHistory = Stats<int16_t, 8192, PAWN_HISTORY_SIZE, PIECE_NB, SQUARE_NB>;
-
-// Correction histories record differences between the static evaluation of
-// positions and their search score. It is used to improve the static evaluation
-// used by some search heuristics.
-// see https://www.chessprogramming.org/Static_Evaluation_Correction_History
-enum CorrHistType {
-    Pawn,          // By color and pawn structure
-    Material,      // By color and material configuration
-    Major,         // By color and positions of major pieces (Queen, Rook) and King
-    Minor,         // By color and positions of minor pieces (Knight, Bishop) and King
-    NonPawn,       // By color and non-pawn material positions
-    PieceTo,       // By [piece][to] move
-    Continuation,  // Combined history of move pairs
-};
-
-template<CorrHistType _>
-struct CorrHistTypedef {
-    using type = Stats<int16_t, CORRECTION_HISTORY_LIMIT, COLOR_NB, CORRECTION_HISTORY_SIZE>;
-};
-
-template<>
-struct CorrHistTypedef<PieceTo> {
-    using type = Stats<int16_t, CORRECTION_HISTORY_LIMIT, PIECE_NB, SQUARE_NB>;
-};
-
-template<>
-struct CorrHistTypedef<Continuation> {
-    using type = Stats<CorrHistTypedef<PieceTo>::type, NOT_USED, PIECE_NB, SQUARE_NB>;
-};
-
-template<CorrHistType T>
-using CorrectionHistory = typename CorrHistTypedef<T>::type;
+class Position;
 
 // The 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 emits one