diff --git a/src/movepick.cpp b/src/movepick.cpp index 025f5b82..575c9022 100644 --- a/src/movepick.cpp +++ b/src/movepick.cpp @@ -56,10 +56,10 @@ namespace { /// ordering is at the current node. /// MovePicker constructor for the main search -MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const ButterflyHistory* mh, - const CapturePieceToHistory* cph, const PieceToHistory** ch, Move cm, Move* killers) - : pos(p), mainHistory(mh), captureHistory(cph), continuationHistory(ch), - refutations{{killers[0], 0}, {killers[1], 0}, {cm, 0}}, depth(d) { +MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const ButterflyHistory* mh, const LowPlyHistory* lp, + const CapturePieceToHistory* cph, const PieceToHistory** ch, Move cm, Move* killers, int pl) + : pos(p), mainHistory(mh), lowPlyHistory(lp), captureHistory(cph), continuationHistory(ch), + refutations{{killers[0], 0}, {killers[1], 0}, {cm, 0}}, depth(d) , ply(pl) { assert(d > 0); @@ -115,7 +115,8 @@ void MovePicker::score() { + 2 * (*continuationHistory[0])[pos.moved_piece(m)][to_sq(m)] + 2 * (*continuationHistory[1])[pos.moved_piece(m)][to_sq(m)] + 2 * (*continuationHistory[3])[pos.moved_piece(m)][to_sq(m)] - + (*continuationHistory[5])[pos.moved_piece(m)][to_sq(m)]; + + (*continuationHistory[5])[pos.moved_piece(m)][to_sq(m)] + + (ply < MAX_LPH ? 4 * (*lowPlyHistory)[ply][from_to(m)] : 0); else // Type == EVASIONS { diff --git a/src/movepick.h b/src/movepick.h index cdedc9b6..33c4b086 100644 --- a/src/movepick.h +++ b/src/movepick.h @@ -88,6 +88,12 @@ enum StatsType { NoCaptures, Captures }; /// 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 www.chessprogramming.org/Countermove_Heuristic typedef Stats CounterMoveHistory; @@ -123,10 +129,12 @@ public: const PieceToHistory**, Square); MovePicker(const Position&, Move, Depth, const ButterflyHistory*, + const LowPlyHistory*, const CapturePieceToHistory*, const PieceToHistory**, Move, - Move*); + Move*, + int); Move next_move(bool skipQuiets = false); private: @@ -137,6 +145,7 @@ private: const Position& pos; const ButterflyHistory* mainHistory; + const LowPlyHistory* lowPlyHistory; const CapturePieceToHistory* captureHistory; const PieceToHistory** continuationHistory; Move ttMove; @@ -145,6 +154,7 @@ private: Square recaptureSquare; Value threshold; Depth depth; + int ply; ExtMove moves[MAX_MOVES]; }; diff --git a/src/search.cpp b/src/search.cpp index c3ebf9ab..3f860ac5 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -156,7 +156,7 @@ namespace { Value value_from_tt(Value v, int ply, int r50c); void update_pv(Move* pv, Move move, Move* childPv); void update_continuation_histories(Stack* ss, Piece pc, Square to, int bonus); - void update_quiet_stats(const Position& pos, Stack* ss, Move move, int bonus); + void update_quiet_stats(const Position& pos, Stack* ss, Move move, int bonus, int depth); void update_all_stats(const Position& pos, Stack* ss, Move bestMove, Value bestValue, Value beta, Square prevSq, Move* quietsSearched, int quietCount, Move* capturesSearched, int captureCount, Depth depth); @@ -695,6 +695,10 @@ namespace { ttMove = rootNode ? thisThread->rootMoves[thisThread->pvIdx].pv[0] : ttHit ? tte->move() : MOVE_NONE; ttPv = PvNode || (ttHit && tte->is_pv()); + + if (ttPv && depth > 12 && ss->ply - 1 < MAX_LPH && !pos.captured_piece() && is_ok((ss-1)->currentMove)) + thisThread->lowPlyHistory[ss->ply - 1][from_to((ss-1)->currentMove)] << stat_bonus(depth - 5); + // thisThread->ttHitAverage can be used to approximate the running average of ttHit thisThread->ttHitAverage = (ttHitAverageWindow - 1) * thisThread->ttHitAverage / ttHitAverageWindow + ttHitAverageResolution * ttHit; @@ -713,7 +717,7 @@ namespace { if (ttValue >= beta) { if (!pos.capture_or_promotion(ttMove)) - update_quiet_stats(pos, ss, ttMove, stat_bonus(depth)); + update_quiet_stats(pos, ss, ttMove, stat_bonus(depth), depth); // Extra penalty for early quiet moves of the previous ply if ((ss-1)->moveCount <= 2 && !priorCapture) @@ -948,10 +952,12 @@ moves_loop: // When in check, search starts from here Move countermove = thisThread->counterMoves[pos.piece_on(prevSq)][prevSq]; MovePicker mp(pos, ttMove, depth, &thisThread->mainHistory, + &thisThread->lowPlyHistory, &thisThread->captureHistory, contHist, countermove, - ss->killers); + ss->killers, + depth > 12 && ttPv ? ss->ply : MAX_PLY); value = bestValue; singularLMR = moveCountPruning = false; @@ -1633,7 +1639,7 @@ moves_loop: // When in check, search starts from here if (!pos.capture_or_promotion(bestMove)) { - update_quiet_stats(pos, ss, bestMove, bonus2); + update_quiet_stats(pos, ss, bestMove, bonus2, depth); // Decrease all the non-best quiet moves for (int i = 0; i < quietCount; ++i) @@ -1673,7 +1679,7 @@ moves_loop: // When in check, search starts from here // update_quiet_stats() updates move sorting heuristics - void update_quiet_stats(const Position& pos, Stack* ss, Move move, int bonus) { + void update_quiet_stats(const Position& pos, Stack* ss, Move move, int bonus, int depth) { if (ss->killers[0] != move) { @@ -1694,6 +1700,9 @@ moves_loop: // When in check, search starts from here Square prevSq = to_sq((ss-1)->currentMove); thisThread->counterMoves[pos.piece_on(prevSq)][prevSq] = move; } + + if (depth > 12 && ss->ply < MAX_LPH) + thisThread->lowPlyHistory[ss->ply][from_to(move)] << stat_bonus(depth - 7); } // When playing with strength handicap, choose best move among a set of RootMoves diff --git a/src/thread.cpp b/src/thread.cpp index 10ec96dd..b5cb87d9 100644 --- a/src/thread.cpp +++ b/src/thread.cpp @@ -68,6 +68,7 @@ void Thread::clear() { counterMoves.fill(MOVE_NONE); mainHistory.fill(0); + lowPlyHistory.fill(0); captureHistory.fill(0); for (bool inCheck : { false, true }) @@ -211,6 +212,7 @@ void ThreadPool::start_thinking(Position& pos, StateListPtr& states, th->rootDepth = th->completedDepth = 0; th->rootMoves = rootMoves; th->rootPos.set(pos.fen(), pos.is_chess960(), &setupStates->back(), th); + th->lowPlyHistory.fill(0); } setupStates->back() = tmp; diff --git a/src/thread.h b/src/thread.h index 63629e33..41d2b8f6 100644 --- a/src/thread.h +++ b/src/thread.h @@ -71,6 +71,7 @@ public: Depth rootDepth, completedDepth; CounterMoveHistory counterMoves; ButterflyHistory mainHistory; + LowPlyHistory lowPlyHistory; CapturePieceToHistory captureHistory; ContinuationHistory continuationHistory[2][2]; Score contempt;