History code rewrite (#1122)
Rearrange and rename all history heuristic code. Naming is now based on chessprogramming.wikispaces.com conventions and the relations among the various heuristics are now more clear and consistent. No functional change.pull/1096/merge
Marco Costalba
GitHub
parent
24df0f72c0
commit
ecd3218b6b
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@ -143,11 +143,11 @@ void MovePicker::score<CAPTURES>() {
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template<>
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void MovePicker::score<QUIETS>() {
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const HistoryStats& history = pos.this_thread()->history;
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const ButterflyHistory& history = pos.this_thread()->history;
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const CounterMoveStats& cmh = *(ss-1)->counterMoves;
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const CounterMoveStats& fmh = *(ss-2)->counterMoves;
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const CounterMoveStats& fm2 = *(ss-4)->counterMoves;
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const PieceToHistory& cmh = *(ss-1)->history;
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const PieceToHistory& fmh = *(ss-2)->history;
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const PieceToHistory& fm2 = *(ss-4)->history;
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Color c = pos.side_to_move();
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@ -155,21 +155,21 @@ void MovePicker::score<QUIETS>() {
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m.value = cmh[pos.moved_piece(m)][to_sq(m)]
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+ fmh[pos.moved_piece(m)][to_sq(m)]
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+ fm2[pos.moved_piece(m)][to_sq(m)]
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+ history.get(c, m);
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+ history[c][from_to(m)];
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}
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template<>
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void MovePicker::score<EVASIONS>() {
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// Try captures ordered by MVV/LVA, then non-captures ordered by stats heuristics
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const HistoryStats& history = pos.this_thread()->history;
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const ButterflyHistory& history = pos.this_thread()->history;
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Color c = pos.side_to_move();
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for (auto& m : *this)
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if (pos.capture(m))
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m.value = PieceValue[MG][pos.piece_on(to_sq(m))]
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- Value(type_of(pos.moved_piece(m))) + HistoryStats::Max;
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- Value(type_of(pos.moved_piece(m))) + (1 << 28);
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else
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m.value = history.get(c, m);
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m.value = history[c][from_to(m)];
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}
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@ -21,68 +21,70 @@
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#ifndef MOVEPICK_H_INCLUDED
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#define MOVEPICK_H_INCLUDED
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#include <cstring> // For std::memset
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#include <array>
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#include "movegen.h"
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#include "position.h"
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#include "types.h"
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/// StatBoards is a generic 2-dimensional array used to store various statistics
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template<int Size1, int Size2, typename T = int>
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struct StatBoards : public std::array<std::array<T, Size2>, Size1> {
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/// HistoryStats records how often quiet moves have been successful or unsuccessful
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/// during the current search, and is used for reduction and move ordering decisions.
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struct HistoryStats {
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void fill(const T& v) {
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T* p = &(*this)[0][0];
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std::fill(p, p + sizeof(*this) / sizeof(*p), v);
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}
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};
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static const int Max = 1 << 28;
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/// ButterflyBoards are 2 tables (one for each color) indexed by the move's from
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/// and to squares, see chessprogramming.wikispaces.com/Butterfly+Boards
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typedef StatBoards<COLOR_NB, int(SQUARE_NB) * int(SQUARE_NB)> ButterflyBoards;
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/// PieceToBoards are addressed by a move's [piece][to] information
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typedef StatBoards<PIECE_NB, SQUARE_NB> PieceToBoards;
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/// ButterflyHistory records how often quiet moves have been successful or
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/// unsuccessful during the current search, and is used for reduction and move
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/// ordering decisions. It uses ButterflyBoards as backing store.
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struct ButterflyHistory : public ButterflyBoards {
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int get(Color c, Move m) const { return table[c][from_sq(m)][to_sq(m)]; }
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void clear() { std::memset(table, 0, sizeof(table)); }
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void update(Color c, Move m, int v) {
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Square from = from_sq(m);
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Square to = to_sq(m);
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const int D = 324;
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int& entry = (*this)[c][from_to(m)];
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assert(abs(v) <= D); // Consistency check for below formula
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table[c][from][to] -= table[c][from][to] * abs(v) / D;
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table[c][from][to] += v * 32;
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}
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entry += v * 32 - entry * abs(v) / D;
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private:
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int table[COLOR_NB][SQUARE_NB][SQUARE_NB];
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assert(abs(entry) <= 32 * D);
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}
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};
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/// PieceToHistory is like ButterflyHistory, but is based on PieceToBoards
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struct PieceToHistory : public PieceToBoards {
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/// A template struct, used to generate MoveStats and CounterMoveHistoryStats:
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/// MoveStats store the move that refute a previous one.
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/// CounterMoveHistoryStats is like HistoryStats, but with two consecutive moves.
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/// Entries are stored using only the moving piece and destination square, hence
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/// two moves with different origin but same destination and piece will be
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/// considered identical.
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template<typename T>
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struct Stats {
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const T* operator[](Piece pc) const { return table[pc]; }
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T* operator[](Piece pc) { return table[pc]; }
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void clear() { std::memset(table, 0, sizeof(table)); }
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void update(Piece pc, Square to, Move m) { table[pc][to] = m; }
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void update(Piece pc, Square to, int v) {
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const int D = 936;
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int& entry = (*this)[pc][to];
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assert(abs(v) <= D); // Consistency check for below formula
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table[pc][to] -= table[pc][to] * abs(v) / D;
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table[pc][to] += v * 32;
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}
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entry += v * 32 - entry * abs(v) / D;
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private:
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T table[PIECE_NB][SQUARE_NB];
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assert(abs(entry) <= 32 * D);
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}
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};
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typedef Stats<Move> MoveStats;
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typedef Stats<int> CounterMoveStats;
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typedef Stats<CounterMoveStats> CounterMoveHistoryStats;
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/// CounterMoveStat stores counter moves indexed by [piece][to] of the previous
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/// move, see chessprogramming.wikispaces.com/Countermove+Heuristic
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typedef StatBoards<PIECE_NB, SQUARE_NB, Move> CounterMoveStat;
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/// CounterMoveHistoryStat is like CounterMoveStat but instead of a move it
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/// stores a full history (based on PieceTo boards instead of ButterflyBoards).
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typedef StatBoards<PIECE_NB, SQUARE_NB, PieceToHistory> CounterMoveHistoryStat;
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/// MovePicker class is used to pick one pseudo legal move at a time from the
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@ -193,14 +193,15 @@ void Search::clear() {
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for (Thread* th : Threads)
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{
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th->counterMoves.clear();
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th->history.clear();
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th->counterMoveHistory.clear();
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th->resetCalls = true;
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th->counterMoves.fill(MOVE_NONE);
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th->history.fill(0);
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CounterMoveStats& cm = th->counterMoveHistory[NO_PIECE][0];
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auto* t = &cm[NO_PIECE][0];
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std::fill(t, t + sizeof(cm)/sizeof(*t), CounterMovePruneThreshold - 1);
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for (auto& to : th->counterMoveHistory)
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for (auto& h : to)
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h.fill(0);
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th->counterMoveHistory[NO_PIECE][0].fill(CounterMovePruneThreshold - 1);
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}
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Threads.main()->previousScore = VALUE_INFINITE;
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@ -334,7 +335,7 @@ void Thread::search() {
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std::memset(ss-4, 0, 7 * sizeof(Stack));
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for(int i = 4; i > 0; i--)
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(ss-i)->counterMoves = &this->counterMoveHistory[NO_PIECE][0]; // Use as sentinel
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(ss-i)->history = &this->counterMoveHistory[NO_PIECE][0]; // Use as sentinel
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bestValue = delta = alpha = -VALUE_INFINITE;
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beta = VALUE_INFINITE;
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@ -558,7 +559,7 @@ namespace {
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Thread* thisThread = pos.this_thread();
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inCheck = pos.checkers();
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moveCount = quietCount = ss->moveCount = 0;
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ss->history = 0;
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ss->statScore = 0;
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bestValue = -VALUE_INFINITE;
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ss->ply = (ss-1)->ply + 1;
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@ -607,7 +608,7 @@ namespace {
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assert(0 <= ss->ply && ss->ply < MAX_PLY);
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ss->currentMove = (ss+1)->excludedMove = bestMove = MOVE_NONE;
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ss->counterMoves = &thisThread->counterMoveHistory[NO_PIECE][0];
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ss->history = &thisThread->counterMoveHistory[NO_PIECE][0];
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(ss+2)->killers[0] = (ss+2)->killers[1] = MOVE_NONE;
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Square prevSq = to_sq((ss-1)->currentMove);
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@ -750,7 +751,7 @@ namespace {
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Depth R = ((823 + 67 * depth / ONE_PLY) / 256 + std::min((eval - beta) / PawnValueMg, 3)) * ONE_PLY;
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ss->currentMove = MOVE_NULL;
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ss->counterMoves = &thisThread->counterMoveHistory[NO_PIECE][0];
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ss->history = &thisThread->counterMoveHistory[NO_PIECE][0];
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pos.do_null_move(st);
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Value nullValue = depth-R < ONE_PLY ? -qsearch<NonPV, false>(pos, ss+1, -beta, -beta+1)
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@ -794,7 +795,7 @@ namespace {
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if (pos.legal(move))
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{
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ss->currentMove = move;
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ss->counterMoves = &thisThread->counterMoveHistory[pos.moved_piece(move)][to_sq(move)];
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ss->history = &thisThread->counterMoveHistory[pos.moved_piece(move)][to_sq(move)];
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pos.do_move(move, st);
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value = -search<NonPV>(pos, ss+1, -rbeta, -rbeta+1, rdepth, !cutNode, false);
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@ -818,9 +819,9 @@ namespace {
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moves_loop: // When in check search starts from here
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const CounterMoveStats& cmh = *(ss-1)->counterMoves;
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const CounterMoveStats& fmh = *(ss-2)->counterMoves;
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const CounterMoveStats& fm2 = *(ss-4)->counterMoves;
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const PieceToHistory& cmh = *(ss-1)->history;
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const PieceToHistory& fmh = *(ss-2)->history;
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const PieceToHistory& fm2 = *(ss-4)->history;
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MovePicker mp(pos, ttMove, depth, ss);
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value = bestValue; // Workaround a bogus 'uninitialized' warning under gcc
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@ -956,7 +957,7 @@ moves_loop: // When in check search starts from here
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// Update the current move (this must be done after singular extension search)
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ss->currentMove = move;
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ss->counterMoves = &thisThread->counterMoveHistory[moved_piece][to_sq(move)];
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ss->history = &thisThread->counterMoveHistory[moved_piece][to_sq(move)];
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// Step 14. Make the move
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pos.do_move(move, st, givesCheck);
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@ -984,21 +985,21 @@ moves_loop: // When in check search starts from here
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&& !pos.see_ge(make_move(to_sq(move), from_sq(move))))
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r -= 2 * ONE_PLY;
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ss->history = cmh[moved_piece][to_sq(move)]
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+ fmh[moved_piece][to_sq(move)]
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+ fm2[moved_piece][to_sq(move)]
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+ thisThread->history.get(~pos.side_to_move(), move)
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- 4000; // Correction factor
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ss->statScore = cmh[moved_piece][to_sq(move)]
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+ fmh[moved_piece][to_sq(move)]
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+ fm2[moved_piece][to_sq(move)]
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+ thisThread->history[~pos.side_to_move()][from_to(move)]
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- 4000; // Correction factor
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// Decrease/increase reduction by comparing opponent's stat score
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if (ss->history > 0 && (ss-1)->history < 0)
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if (ss->statScore > 0 && (ss-1)->statScore < 0)
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r -= ONE_PLY;
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else if (ss->history < 0 && (ss-1)->history > 0)
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else if (ss->statScore < 0 && (ss-1)->statScore > 0)
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r += ONE_PLY;
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// Decrease/increase reduction for moves with a good/bad history
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r = std::max(DEPTH_ZERO, (r / ONE_PLY - ss->history / 20000) * ONE_PLY);
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r = std::max(DEPTH_ZERO, (r / ONE_PLY - ss->statScore / 20000) * ONE_PLY);
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}
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Depth d = std::max(newDepth - r, ONE_PLY);
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@ -1399,7 +1400,7 @@ moves_loop: // When in check search starts from here
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for (int i : {1, 2, 4})
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if (is_ok((ss-i)->currentMove))
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(ss-i)->counterMoves->update(pc, s, bonus);
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(ss-i)->history->update(pc, s, bonus);
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}
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@ -1422,7 +1423,7 @@ moves_loop: // When in check search starts from here
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if (is_ok((ss-1)->currentMove))
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{
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Square prevSq = to_sq((ss-1)->currentMove);
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thisThread->counterMoves.update(pos.piece_on(prevSq), prevSq, move);
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thisThread->counterMoves[pos.piece_on(prevSq)][prevSq]=move;
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}
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// Decrease all the other played quiet moves
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@ -38,13 +38,13 @@ namespace Search {
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struct Stack {
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Move* pv;
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CounterMoveStats* counterMoves;
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PieceToHistory* history;
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int ply;
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Move currentMove;
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Move excludedMove;
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Move killers[2];
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Value staticEval;
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int history;
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int statScore;
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int moveCount;
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};
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@ -68,9 +68,9 @@ public:
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Depth rootDepth;
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Depth completedDepth;
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std::atomic_bool resetCalls;
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MoveStats counterMoves;
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HistoryStats history;
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CounterMoveHistoryStats counterMoveHistory;
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CounterMoveStat counterMoves;
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ButterflyHistory history;
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CounterMoveHistoryStat counterMoveHistory;
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};
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@ -421,6 +421,10 @@ inline Square to_sq(Move m) {
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return Square(m & 0x3F);
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}
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inline int from_to(Move m) {
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return m & 0xFFF;
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}
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inline MoveType type_of(Move m) {
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return MoveType(m & (3 << 14));
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}
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