X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Fsearch.cpp;h=3136046d2f52f6e82ec9cc70ced94eb70b73edb1;hb=38a80c0b47397dbdd9167ec1476dfd3c033020d6;hp=fcdb8d67545fd302ed782f743bc41b9cc6d53912;hpb=5c75c1c2fbb7bb4f0bf7c44fb855c415b788cbf7;p=stockfish diff --git a/src/search.cpp b/src/search.cpp index fcdb8d67..3136046d 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -34,6 +34,7 @@ #include "tt.h" #include "uci.h" #include "syzygy/tbprobe.h" +#include "nnue/evaluate_nnue.h" namespace Stockfish { @@ -292,6 +293,15 @@ void Thread::search() { if (mainThread) { + + int rootComplexity; + if (Eval::useNNUE) + Eval::NNUE::evaluate(rootPos, true, &rootComplexity); + else + Eval::evaluate(rootPos, &rootComplexity); + + mainThread->complexity = std::min(1.03 + (rootComplexity - 241) / 1552.0, 1.45); + if (mainThread->bestPreviousScore == VALUE_INFINITE) for (int i = 0; i < 4; ++i) mainThread->iterValue[i] = VALUE_ZERO; @@ -310,8 +320,6 @@ void Thread::search() { multiPV = std::min(multiPV, rootMoves.size()); - complexityAverage.set(153, 1); - optimism[us] = optimism[~us] = VALUE_ZERO; int searchAgainCounter = 0; @@ -471,10 +479,8 @@ void Thread::search() { timeReduction = lastBestMoveDepth + 8 < completedDepth ? 1.57 : 0.65; double reduction = (1.4 + mainThread->previousTimeReduction) / (2.08 * timeReduction); double bestMoveInstability = 1 + 1.8 * totBestMoveChanges / Threads.size(); - int complexity = mainThread->complexityAverage.value(); - double complexPosition = std::min(1.03 + (complexity - 241) / 1552.0, 1.45); - double totalTime = Time.optimum() * fallingEval * reduction * bestMoveInstability * complexPosition; + double totalTime = Time.optimum() * fallingEval * reduction * bestMoveInstability * mainThread->complexity; // Cap used time in case of a single legal move for a better viewer experience in tournaments // yielding correct scores and sufficiently fast moves. @@ -601,20 +607,12 @@ namespace { assert(0 <= ss->ply && ss->ply < MAX_PLY); - (ss+1)->ttPv = false; (ss+1)->excludedMove = bestMove = MOVE_NONE; (ss+2)->killers[0] = (ss+2)->killers[1] = MOVE_NONE; (ss+2)->cutoffCnt = 0; ss->doubleExtensions = (ss-1)->doubleExtensions; - Square prevSq = to_sq((ss-1)->currentMove); - - // Initialize statScore to zero for the grandchildren of the current position. - // So statScore is shared between all grandchildren and only the first grandchild - // starts with statScore = 0. Later grandchildren start with the last calculated - // statScore of the previous grandchild. This influences the reduction rules in - // LMR which are based on the statScore of parent position. - if (!rootNode) - (ss+2)->statScore = 0; + Square prevSq = is_ok((ss-1)->currentMove) ? to_sq((ss-1)->currentMove) : SQ_NONE; + ss->statScore = 0; // Step 4. Transposition table lookup. excludedMove = ss->excludedMove; @@ -648,7 +646,7 @@ namespace { update_quiet_stats(pos, ss, ttMove, stat_bonus(depth)); // Extra penalty for early quiet moves of the previous ply (~0 Elo on STC, ~2 Elo on LTC) - if ((ss-1)->moveCount <= 2 && !priorCapture) + if (prevSq != SQ_NONE && (ss-1)->moveCount <= 2 && !priorCapture) update_continuation_histories(ss-1, pos.piece_on(prevSq), prevSq, -stat_bonus(depth + 1)); } // Penalty for a quiet ttMove that fails low (~1 Elo) @@ -732,7 +730,7 @@ namespace { } else if (excludedMove) { - // Providing the hint that this node's accumulator will be used often brings significant Elo gain (13 elo) + // Providing the hint that this node's accumulator will be used often brings significant Elo gain (13 Elo) Eval::NNUE::hint_common_parent_position(pos); eval = ss->staticEval; complexity = abs(ss->staticEval - pos.psq_eg_stm()); @@ -762,8 +760,6 @@ namespace { tte->save(posKey, VALUE_NONE, ss->ttPv, BOUND_NONE, DEPTH_NONE, MOVE_NONE, eval); } - thisThread->complexityAverage.update(complexity); - // Use static evaluation difference to improve quiet move ordering (~4 Elo) if (is_ok((ss-1)->currentMove) && !(ss-1)->inCheck && !priorCapture) { @@ -936,7 +932,7 @@ moves_loop: // When in check, search starts here nullptr , (ss-4)->continuationHistory, nullptr , (ss-6)->continuationHistory }; - Move countermove = thisThread->counterMoves[pos.piece_on(prevSq)][prevSq]; + Move countermove = prevSq != SQ_NONE ? thisThread->counterMoves[pos.piece_on(prevSq)][prevSq] : MOVE_NONE; MovePicker mp(pos, ttMove, depth, &thisThread->mainHistory, &captureHistory, @@ -1012,16 +1008,33 @@ moves_loop: // When in check, search starts here { // Futility pruning for captures (~2 Elo) if ( !givesCheck - && !PvNode && lmrDepth < 6 && !ss->inCheck && ss->staticEval + 182 + 230 * lmrDepth + PieceValue[EG][pos.piece_on(to_sq(move))] + captureHistory[movedPiece][to_sq(move)][type_of(pos.piece_on(to_sq(move)))] / 7 < alpha) continue; + Bitboard occupied; // SEE based pruning (~11 Elo) - if (!pos.see_ge(move, Value(-206) * depth)) - continue; + if (!pos.see_ge(move, occupied, Value(-206) * depth)) + { + if (depth < 2 - capture) + continue; + // don't prune move if a heavy enemy piece (KQR) is under attack after the exchanges + Bitboard leftEnemies = (pos.pieces(~us, QUEEN, ROOK) | pos.pieces(~us, KING)) & occupied; + Bitboard attacks = 0; + occupied |= to_sq(move); + while (leftEnemies && !attacks) + { + Square sq = pop_lsb(leftEnemies); + attacks |= pos.attackers_to(sq, occupied) & pos.pieces(us) & occupied; + // exclude Queen/Rook(s) which were already threatened before SEE + if (attacks && (sq != pos.square(~us) && (pos.attackers_to(sq, pos.pieces()) & pos.pieces(us)))) + attacks = 0; + } + if (!attacks) + continue; + } } else { @@ -1071,11 +1084,10 @@ moves_loop: // When in check, search starts here && (tte->bound() & BOUND_LOWER) && tte->depth() >= depth - 3) { - Value singularBeta = ttValue - (2 + (ss->ttPv && !PvNode)) * depth; + Value singularBeta = ttValue - (3 + 2 * (ss->ttPv && !PvNode)) * depth / 2; Depth singularDepth = (depth - 1) / 2; ss->excludedMove = move; - // the search with excludedMove will update ss->staticEval value = search(pos, ss, singularBeta - 1, singularBeta, singularDepth, cutNode); ss->excludedMove = MOVE_NONE; @@ -1102,13 +1114,17 @@ moves_loop: // When in check, search starts here else if (singularBeta >= beta) return singularBeta; - // If the eval of ttMove is greater than beta, we reduce it (negative extension) + // If the eval of ttMove is greater than beta, we reduce it (negative extension) (~7 Elo) else if (ttValue >= beta) - extension = -2; + extension = -2 - !PvNode; - // If the eval of ttMove is less than value, we reduce it (negative extension) + // If the eval of ttMove is less than value, we reduce it (negative extension) (~1 Elo) else if (ttValue <= value) extension = -1; + + // If the eval of ttMove is less than alpha, we reduce it (negative extension) (~1 Elo) + else if (ttValue <= alpha) + extension = -1; } // Check extensions (~1 Elo) @@ -1160,7 +1176,7 @@ moves_loop: // When in check, search starts here if (ttCapture) r++; - // Decrease reduction for PvNodes based on depth + // Decrease reduction for PvNodes based on depth (~2 Elo) if (PvNode) r -= 1 + 12 / (3 + depth); @@ -1168,16 +1184,11 @@ moves_loop: // When in check, search starts here if (singularQuietLMR) r--; - // Decrease reduction if we move a threatened piece (~1 Elo) - if ( depth > 9 - && (mp.threatenedPieces & from_sq(move))) - r--; - - // Increase reduction if next ply has a lot of fail high + // Increase reduction if next ply has a lot of fail high (~5 Elo) if ((ss+1)->cutoffCnt > 3) r++; - // Decrease reduction if move is a killer and we have a good history + // Decrease reduction if move is a killer and we have a good history (~1 Elo) if (move == ss->killers[0] && (*contHist[0])[movedPiece][to_sq(move)] >= 3722) r--; @@ -1188,7 +1199,7 @@ moves_loop: // When in check, search starts here + (*contHist[3])[movedPiece][to_sq(move)] - 4182; - // Decrease/increase reduction for moves with a good/bad history (~30 Elo) + // Decrease/increase reduction for moves with a good/bad history (~25 Elo) r -= ss->statScore / (11791 + 3992 * (depth > 6 && depth < 19)); // Step 17. Late moves reduction / extension (LMR, ~117 Elo) @@ -1325,7 +1336,7 @@ moves_loop: // When in check, search starts here { alpha = value; - // Reduce other moves if we have found at least one score improvement + // Reduce other moves if we have found at least one score improvement (~1 Elo) if ( depth > 1 && depth < 6 && beta < 10534 @@ -1381,7 +1392,7 @@ moves_loop: // When in check, search starts here quietsSearched, quietCount, capturesSearched, captureCount, depth); // Bonus for prior countermove that caused the fail low - else if (!priorCapture) + else if (!priorCapture && prevSq != SQ_NONE) { int bonus = (depth > 5) + (PvNode || cutNode) + (bestValue < alpha - 97 * depth) + ((ss-1)->moveCount > 10); update_continuation_histories(ss-1, pos.piece_on(prevSq), prevSq, stat_bonus(depth) * bonus); @@ -1391,7 +1402,7 @@ moves_loop: // When in check, search starts here bestValue = std::min(bestValue, maxValue); // If no good move is found and the previous position was ttPv, then the previous - // opponent move is probably good and the new position is added to the search tree. + // opponent move is probably good and the new position is added to the search tree. (~7 Elo) if (bestValue <= alpha) ss->ttPv = ss->ttPv || ((ss-1)->ttPv && depth > 3); @@ -1410,7 +1421,7 @@ moves_loop: // When in check, search starts here // qsearch() is the quiescence search function, which is called by the main search // function with zero depth, or recursively with further decreasing depth per call. - // (~155 elo) + // (~155 Elo) template Value qsearch(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth) { @@ -1523,7 +1534,7 @@ moves_loop: // When in check, search starts here // to search the moves. Because the depth is <= 0 here, only captures, // queen promotions, and other checks (only if depth >= DEPTH_QS_CHECKS) // will be generated. - Square prevSq = to_sq((ss-1)->currentMove); + Square prevSq = (ss-1)->currentMove != MOVE_NULL ? to_sq((ss-1)->currentMove) : SQ_NONE; MovePicker mp(pos, ttMove, depth, &thisThread->mainHistory, &thisThread->captureHistory, contHist, @@ -1712,7 +1723,8 @@ moves_loop: // When in check, search starts here Thread* thisThread = pos.this_thread(); CapturePieceToHistory& captureHistory = thisThread->captureHistory; Piece moved_piece = pos.moved_piece(bestMove); - PieceType captured = type_of(pos.piece_on(to_sq(bestMove))); + PieceType captured; + int bonus1 = stat_bonus(depth + 1); if (!pos.capture_stage(bestMove)) @@ -1731,12 +1743,16 @@ moves_loop: // When in check, search starts here } } else + { // Increase stats for the best move in case it was a capture move + captured = type_of(pos.piece_on(to_sq(bestMove))); captureHistory[moved_piece][to_sq(bestMove)][captured] << bonus1; + } // Extra penalty for a quiet early move that was not a TT move or // main killer move in previous ply when it gets refuted. - if ( ((ss-1)->moveCount == 1 + (ss-1)->ttHit || ((ss-1)->currentMove == (ss-1)->killers[0])) + if ( prevSq != SQ_NONE + && ((ss-1)->moveCount == 1 + (ss-1)->ttHit || ((ss-1)->currentMove == (ss-1)->killers[0])) && !pos.captured_piece()) update_continuation_histories(ss-1, pos.piece_on(prevSq), prevSq, -bonus1);