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Merge Stats tables

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Use a recursive std::array with variadic template
parameters to get rid of the last redundacy.

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.

This allows greater flexibility because we can now tweak
the range [-W * D, W * D] for each table.

Patch removes more lines than what adds and streamlines
the Stats soup in movepick.h

Closes PR#1422 and PR#1421

No functional change.
This commit is contained in:
Marco Costalba
2018-03-03 11:29:29 +01:00
committed by Stéphane Nicolet
parent 94b3cdd908
commit f35e52f030
4 changed files with 65 additions and 76 deletions
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113
src/movepick.h
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@@ -23,44 +23,33 @@
#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
template<int Size1, int Size2, typename T = int16_t>
struct StatBoards : public std::array<std::array<T, Size2>, 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<typename T, int W, int D>
class StatsEntry {
void fill(const T& v) {
T* p = &(*this)[0][0];
std::fill(p, p + sizeof(*this) / sizeof(*p), v);
}
static const bool IsInt = std::is_integral<T>::value;
typedef typename std::conditional<IsInt, int, T>::type TT;
void update(T& entry, int bonus, const int D) {
T entry;
assert(abs(bonus) <= D); // Ensure range is [-32 * D, 32 * D]
assert(abs(32 * D) < (std::numeric_limits<T>::max)()); // Ensure we don't overflow
public:
T* get() { return &entry; }
void operator=(const T& v) { entry = v; }
operator TT() const { return entry; }
entry += bonus * 32 - entry * abs(bonus) / D;
assert(abs(entry) <= 32 * D);
}
};
/// StatCubes is a generic 3-dimensional array used to store various statistics
template<int Size1, int Size2, int Size3, typename T = int16_t>
struct StatCubes : public std::array<std::array<std::array<T, Size3>, Size2>, Size1> {
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) {
void operator<<(int bonus) {
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
assert(abs(W * D) < std::numeric_limits<T>::max()); // Ensure we don't overflow
entry += bonus * W - entry * abs(bonus) / D;
@@ -68,50 +57,50 @@ struct StatCubes : public std::array<std::array<std::array<T, Size3>, Size2>, Si
}
};
/// 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<COLOR_NB, int(SQUARE_NB) * int(SQUARE_NB)> ButterflyBoards;
/// 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 <typename T, int W, int D, int Size, int... Sizes>
struct Stats : public std::array<Stats<T, W, D, Sizes...>, Size>
{
T* get() { return this->at(0).get(); }
/// PieceToBoards are addressed by a move's [piece][to] information
typedef StatBoards<PIECE_NB, SQUARE_NB> PieceToBoards;
void fill(const T& v) {
T* p = get();
std::fill(p, p + sizeof(*this) / sizeof(*p), v);
}
};
/// CapturePieceToBoards are addressed by a move's [piece][to][captured piece type] information
typedef StatCubes<PIECE_NB, SQUARE_NB, PIECE_TYPE_NB> CapturePieceToBoards;
template <typename T, int W, int D, int Size>
struct Stats<T, W, D, Size> : public std::array<StatsEntry<T, W, D>, Size> {
T* get() { return this->at(0).get(); }
};
/// 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 };
/// 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);
}
};
/// PieceToHistory is like ButterflyHistory, but is based on PieceToBoards
struct PieceToHistory : public PieceToBoards {
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 {
void update(Piece pc, Square to, PieceType captured, int bonus) {
StatCubes::update((*this)[pc][to][captured], bonus, 324, 2);
}
};
/// 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<int16_t, W32, D324, COLOR_NB, int(SQUARE_NB) * int(SQUARE_NB)> ButterflyHistory;
/// 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;
typedef Stats<Move, NOT_USED, NOT_USED, PIECE_NB, SQUARE_NB> CounterMoveHistory;
/// 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<PIECE_NB, SQUARE_NB, PieceToHistory> ContinuationHistory;
/// CapturePieceToHistory is addressed by a move's [piece][to][captured piece type]
typedef Stats<int16_t, W2, D324, PIECE_NB, SQUARE_NB, PIECE_TYPE_NB> CapturePieceToHistory;
/// PieceToHistory is like ButterflyHistory but is addressed by a move's [piece][to]
typedef Stats<int16_t, W32, D936, PIECE_NB, SQUARE_NB> 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<PieceToHistory, W32, NOT_USED, PIECE_NB, SQUARE_NB> ContinuationHistory;
/// MovePicker class is used to pick one pseudo legal move at a time from the