X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=9165468ae0590e82740f53c7296f7aef9f7ce643;hp=d3f1335bdb06292e2fff341a98ba1ee9c8edafad;hb=4d0981fef37c85edfd7a0e713d68a4542d7a6784;hpb=82ff04b992a53c757519a6ff61576ebd267c0cee diff --git a/src/search.cpp b/src/search.cpp index d3f1335b..9165468a 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -71,12 +71,16 @@ namespace { return Value((175 - 50 * improving) * d / ONE_PLY); } - // Futility and reductions lookup tables, initialized at startup - int FutilityMoveCounts[2][16]; // [improving][depth] - int Reductions[2][64][64]; // [improving][depth][moveNumber] + // Reductions lookup table, initialized at startup + int Reductions[64]; // [depth or moveNumber] template Depth reduction(bool i, Depth d, int mn) { - return (Reductions[i][std::min(d / ONE_PLY, 63)][std::min(mn, 63)] - PvNode) * ONE_PLY; + int r = Reductions[std::min(d / ONE_PLY, 63)] * Reductions[std::min(mn, 63)] / 1024; + return ((r + 512) / 1024 + (!i && r > 1024) - PvNode) * ONE_PLY; + } + + constexpr int futility_move_count(bool improving, int depth) { + return (5 + depth * depth) * (1 + improving) / 2; } // History and stats update bonus, based on depth @@ -156,24 +160,8 @@ namespace { void Search::init() { - for (int imp = 0; imp <= 1; ++imp) - for (int d = 1; d < 64; ++d) - for (int mc = 1; mc < 64; ++mc) - { - double r = log(d) * log(mc) / 1.95; - - Reductions[imp][d][mc] = std::round(r); - - // Increase reduction for non-PV nodes when eval is not improving - if (!imp && r > 1.0) - Reductions[imp][d][mc]++; - } - - for (int d = 0; d < 16; ++d) - { - FutilityMoveCounts[0][d] = int(2.4 + 0.74 * pow(d, 1.78)); - FutilityMoveCounts[1][d] = int(5.0 + 1.00 * pow(d, 2.00)); - } + for (int i = 1; i < 64; ++i) + Reductions[i] = int(1024 * std::log(i) / std::sqrt(1.95)); } @@ -301,7 +289,7 @@ void Thread::search() { // The former is needed to allow update_continuation_histories(ss-1, ...), // which accesses its argument at ss-4, also near the root. // The latter is needed for statScores and killer initialization. - Stack stack[MAX_PLY+8], *ss = stack+5; + Stack stack[MAX_PLY+10], *ss = stack+7; Move pv[MAX_PLY+1]; Value bestValue, alpha, beta, delta; Move lastBestMove = MOVE_NONE; @@ -311,8 +299,8 @@ void Thread::search() { Color us = rootPos.side_to_move(); bool failedLow; - std::memset(ss-5, 0, 8 * sizeof(Stack)); - for (int i = 5; i > 0; i--) + std::memset(ss-7, 0, 10 * sizeof(Stack)); + for (int i = 7; i > 0; i--) (ss-i)->continuationHistory = &this->continuationHistory[NO_PIECE][0]; // Use as sentinel ss->pv = pv; @@ -845,7 +833,7 @@ namespace { // Perform a preliminary qsearch to verify that the move holds value = -qsearch(pos, ss+1, -raisedBeta, -raisedBeta+1); - // If the qsearch held perform the regular search + // If the qsearch held, perform the regular search if (value >= raisedBeta) value = -search(pos, ss+1, -raisedBeta, -raisedBeta+1, depth - 4 * ONE_PLY, !cutNode); @@ -869,7 +857,9 @@ namespace { moves_loop: // When in check, search starts from here - const PieceToHistory* contHist[] = { (ss-1)->continuationHistory, (ss-2)->continuationHistory, nullptr, (ss-4)->continuationHistory }; + const PieceToHistory* contHist[] = { (ss-1)->continuationHistory, (ss-2)->continuationHistory, + nullptr, (ss-4)->continuationHistory, + nullptr, (ss-6)->continuationHistory }; Move countermove = thisThread->counterMoves[pos.piece_on(prevSq)][prevSq]; MovePicker mp(pos, ttMove, depth, &thisThread->mainHistory, @@ -924,12 +914,13 @@ moves_loop: // When in check, search starts from here && move == ttMove && !rootNode && !excludedMove // Avoid recursive singular search - && ttValue != VALUE_NONE + /* && ttValue != VALUE_NONE Already implicit in the next condition */ + && abs(ttValue) < VALUE_KNOWN_WIN && (tte->bound() & BOUND_LOWER) && tte->depth() >= depth - 3 * ONE_PLY && pos.legal(move)) { - Value singularBeta = std::max(ttValue - 2 * depth / ONE_PLY, -VALUE_MATE); + Value singularBeta = ttValue - 2 * depth / ONE_PLY; ss->excludedMove = move; value = search(pos, ss, singularBeta - 1, singularBeta, depth / 2, cutNode); ss->excludedMove = MOVE_NONE; @@ -964,8 +955,7 @@ moves_loop: // When in check, search starts from here && bestValue > VALUE_MATED_IN_MAX_PLY) { // Skip quiet moves if movecount exceeds our FutilityMoveCount threshold - moveCountPruning = depth < 16 * ONE_PLY - && moveCount >= FutilityMoveCounts[improving][depth / ONE_PLY]; + moveCountPruning = moveCount >= futility_move_count(improving,depth / ONE_PLY); if ( !captureOrPromotion && !givesCheck @@ -1320,7 +1310,9 @@ moves_loop: // When in check, search starts from here futilityBase = bestValue + 128; } - const PieceToHistory* contHist[] = { (ss-1)->continuationHistory, (ss-2)->continuationHistory, nullptr, (ss-4)->continuationHistory }; + const PieceToHistory* contHist[] = { (ss-1)->continuationHistory, (ss-2)->continuationHistory, + nullptr, (ss-4)->continuationHistory, + nullptr, (ss-6)->continuationHistory }; // Initialize a MovePicker object for the current position, and prepare // to search the moves. Because the depth is <= 0 here, only captures, @@ -1470,7 +1462,7 @@ moves_loop: // When in check, search starts from here void update_continuation_histories(Stack* ss, Piece pc, Square to, int bonus) { - for (int i : {1, 2, 4}) + for (int i : {1, 2, 4, 6}) if (is_ok((ss-i)->currentMove)) (*(ss-i)->continuationHistory)[pc][to] << bonus; }