X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=5ad650d2dabf25e7c809c1d967e97fa6f37fbf14;hp=a7e90a08552f7ac09f8f093b9da0907284c095f9;hb=42b7dbcb5e20ae9015122601522be8b455787a4a;hpb=221893bf679f70098e6f751fded2fe843471c6be diff --git a/src/search.cpp b/src/search.cpp index a7e90a08..5ad650d2 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -61,13 +61,13 @@ namespace { // Different node types, used as a template parameter enum NodeType { NonPV, PV }; - constexpr uint64_t ttHitAverageWindow = 4096; - constexpr uint64_t ttHitAverageResolution = 1024; + constexpr uint64_t TtHitAverageWindow = 4096; + constexpr uint64_t TtHitAverageResolution = 1024; // Razor and futility margins - constexpr int RazorMargin = 531; + constexpr int RazorMargin = 516; Value futility_margin(Depth d, bool improving) { - return Value(217 * (d - improving)); + return Value(224 * (d - improving)); } // Reductions lookup table, initialized at startup @@ -75,16 +75,16 @@ namespace { Depth reduction(bool i, Depth d, int mn) { int r = Reductions[d] * Reductions[mn]; - return (r + 511) / 1024 + (!i && r > 1007); + return (r + 529) / 1024 + (!i && r > 1050); } constexpr int futility_move_count(bool improving, Depth depth) { - return (4 + depth * depth) / (2 - improving); + return (3 + depth * depth) / (2 - improving); } // History and stats update bonus, based on depth int stat_bonus(Depth d) { - return d > 15 ? -8 : 19 * d * d + 155 * d - 132; + return d > 15 ? 28 : 19 * d * d + 135 * d - 136; } // Add a small random component to draw evaluations to avoid 3fold-blindness @@ -194,7 +194,7 @@ namespace { void Search::init() { for (int i = 1; i < MAX_MOVES; ++i) - Reductions[i] = int((24.8 + std::log(Threads.size())) * std::log(i)); + Reductions[i] = int((24.9 + std::log(Threads.size())) * std::log(i)); } @@ -236,14 +236,8 @@ void MainThread::search() { } else { - for (Thread* th : Threads) - { - th->bestMoveChanges = 0; - if (th != this) - th->start_searching(); - } - - Thread::search(); // Let's start searching! + Threads.start_searching(); // start non-main threads + Thread::search(); // main thread start searching } // When we reach the maximum depth, we can arrive here without a raise of @@ -260,9 +254,7 @@ void MainThread::search() { Threads.stop = true; // Wait until all threads have finished - for (Thread* th : Threads) - if (th != this) - th->wait_for_search_finished(); + Threads.wait_for_search_finished(); // When playing in 'nodes as time' mode, subtract the searched nodes from // the available ones before exiting. @@ -271,37 +263,11 @@ void MainThread::search() { Thread* bestThread = this; - // Check if there are threads with a better score than main thread - if ( Options["MultiPV"] == 1 - && !Limits.depth - && !(Skill(Options["Skill Level"]).enabled() || Options["UCI_LimitStrength"]) - && rootMoves[0].pv[0] != MOVE_NONE) - { - std::map votes; - Value minScore = this->rootMoves[0].score; - - // Find minimum score - for (Thread* th: Threads) - minScore = std::min(minScore, th->rootMoves[0].score); - - // Vote according to score and depth, and select the best thread - for (Thread* th : Threads) - { - votes[th->rootMoves[0].pv[0]] += - (th->rootMoves[0].score - minScore + 14) * int(th->completedDepth); - - if (abs(bestThread->rootMoves[0].score) >= VALUE_TB_WIN_IN_MAX_PLY) - { - // Make sure we pick the shortest mate / TB conversion or stave off mate the longest - if (th->rootMoves[0].score > bestThread->rootMoves[0].score) - bestThread = th; - } - else if ( th->rootMoves[0].score >= VALUE_TB_WIN_IN_MAX_PLY - || ( th->rootMoves[0].score > VALUE_TB_LOSS_IN_MAX_PLY - && votes[th->rootMoves[0].pv[0]] > votes[bestThread->rootMoves[0].pv[0]])) - bestThread = th; - } - } + if (int(Options["MultiPV"]) == 1 && + !Limits.depth && + !(Skill(Options["Skill Level"]).enabled() || int(Options["UCI_LimitStrength"])) && + rootMoves[0].pv[0] != MOVE_NONE) + bestThread = Threads.get_best_thread(); bestPreviousScore = bestThread->rootMoves[0].score; @@ -350,14 +316,17 @@ void Thread::search() { if (mainThread) { if (mainThread->bestPreviousScore == VALUE_INFINITE) - for (int i=0; i<4; ++i) + for (int i = 0; i < 4; ++i) mainThread->iterValue[i] = VALUE_ZERO; else - for (int i=0; i<4; ++i) + for (int i = 0; i < 4; ++i) mainThread->iterValue[i] = mainThread->bestPreviousScore; } - size_t multiPV = Options["MultiPV"]; + std::copy(&lowPlyHistory[2][0], &lowPlyHistory.back().back() + 1, &lowPlyHistory[0][0]); + std::fill(&lowPlyHistory[MAX_LPH - 2][0], &lowPlyHistory.back().back() + 1, 0); + + size_t multiPV = size_t(Options["MultiPV"]); // Pick integer skill levels, but non-deterministically round up or down // such that the average integer skill corresponds to the input floating point one. @@ -378,7 +347,7 @@ void Thread::search() { multiPV = std::max(multiPV, (size_t)4); multiPV = std::min(multiPV, rootMoves.size()); - ttHitAverage = ttHitAverageWindow * ttHitAverageResolution / 2; + ttHitAverage = TtHitAverageWindow * TtHitAverageResolution / 2; int ct = int(Options["Contempt"]) * PawnValueEg / 100; // From centipawns @@ -439,7 +408,7 @@ void Thread::search() { beta = std::min(prev + delta, VALUE_INFINITE); // Adjust contempt based on root move's previousScore (dynamic contempt) - int dct = ct + (102 - ct / 2) * prev / (abs(prev) + 157); + int dct = ct + (104 - ct / 2) * prev / (abs(prev) + 143); contempt = (us == WHITE ? make_score(dct, dct / 2) : -make_score(dct, dct / 2)); @@ -537,13 +506,13 @@ void Thread::search() { && !Threads.stop && !mainThread->stopOnPonderhit) { - double fallingEval = (332 + 6 * (mainThread->bestPreviousScore - bestValue) - + 6 * (mainThread->iterValue[iterIdx] - bestValue)) / 704.0; + double fallingEval = (293 + 6 * (mainThread->bestPreviousScore - bestValue) + + 6 * (mainThread->iterValue[iterIdx] - bestValue)) / 742.0; fallingEval = Utility::clamp(fallingEval, 0.5, 1.5); // If the bestMove is stable over several iterations, reduce time accordingly - timeReduction = lastBestMoveDepth + 9 < completedDepth ? 1.94 : 0.91; - double reduction = (1.41 + mainThread->previousTimeReduction) / (2.27 * timeReduction); + timeReduction = lastBestMoveDepth + 10 < completedDepth ? 1.93 : 0.96; + double reduction = (1.36 + mainThread->previousTimeReduction) / (2.21 * timeReduction); // Use part of the gained time from a previous stable move for the current move for (Thread* th : Threads) @@ -553,9 +522,11 @@ void Thread::search() { } double bestMoveInstability = 1 + totBestMoveChanges / Threads.size(); - // Stop the search if we have only one legal move, or if available time elapsed - if ( rootMoves.size() == 1 - || Time.elapsed() > Time.optimum() * fallingEval * reduction * bestMoveInstability) + double totalTime = rootMoves.size() == 1 ? 0 : + Time.optimum() * fallingEval * reduction * bestMoveInstability; + + // Stop the search if we have exceeded the totalTime, at least 1ms search. + if (Time.elapsed() > totalTime) { // If we are allowed to ponder do not stop the search now but // keep pondering until the GUI sends "ponderhit" or "stop". @@ -566,7 +537,7 @@ void Thread::search() { } else if ( Threads.increaseDepth && !mainThread->ponder - && Time.elapsed() > Time.optimum() * fallingEval * reduction * bestMoveInstability * 0.6) + && Time.elapsed() > totalTime * 0.57) Threads.increaseDepth = false; else Threads.increaseDepth = true; @@ -626,14 +597,15 @@ namespace { Move ttMove, move, excludedMove, bestMove; Depth extension, newDepth; Value bestValue, value, ttValue, eval, maxValue; - bool ttHit, ttPv, formerPv, inCheck, givesCheck, improving, didLMR, priorCapture; - bool captureOrPromotion, doFullDepthSearch, moveCountPruning, ttCapture, singularLMR; + bool ttHit, ttPv, formerPv, givesCheck, improving, didLMR, priorCapture; + bool captureOrPromotion, doFullDepthSearch, moveCountPruning, + ttCapture, singularQuietLMR; Piece movedPiece; int moveCount, captureCount, quietCount; // Step 1. Initialize node Thread* thisThread = pos.this_thread(); - inCheck = pos.checkers(); + ss->inCheck = pos.checkers(); priorCapture = pos.captured_piece(); Color us = pos.side_to_move(); moveCount = captureCount = quietCount = ss->moveCount = 0; @@ -654,7 +626,7 @@ namespace { if ( Threads.stop.load(std::memory_order_relaxed) || pos.is_draw(ss->ply) || ss->ply >= MAX_PLY) - return (ss->ply >= MAX_PLY && !inCheck) ? evaluate(pos) + return (ss->ply >= MAX_PLY && !ss->inCheck) ? evaluate(pos) : value_draw(pos.this_thread()); // Step 3. Mate distance pruning. Even if we mate at the next move our score @@ -702,8 +674,8 @@ namespace { 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; + thisThread->ttHitAverage = (TtHitAverageWindow - 1) * thisThread->ttHitAverage / TtHitAverageWindow + + TtHitAverageResolution * ttHit; // At non-PV nodes we check for an early TT cutoff if ( !PvNode @@ -793,7 +765,7 @@ namespace { CapturePieceToHistory& captureHistory = thisThread->captureHistory; // Step 6. Static evaluation of the position - if (inCheck) + if (ss->inCheck) { ss->staticEval = eval = VALUE_NONE; improving = false; @@ -847,10 +819,10 @@ namespace { // Step 9. Null move search with verification search (~40 Elo) if ( !PvNode && (ss-1)->currentMove != MOVE_NULL - && (ss-1)->statScore < 23397 + && (ss-1)->statScore < 24714 && eval >= beta && eval >= ss->staticEval - && ss->staticEval >= beta - 32 * depth - 30 * improving + 120 * ttPv + 292 + && ss->staticEval >= beta - 29 * depth - 31 * improving + 119 * ttPv + 299 && !excludedMove && pos.non_pawn_material(us) && (ss->ply >= thisThread->nmpMinPly || us != thisThread->nmpColor)) @@ -858,7 +830,7 @@ namespace { assert(eval - beta >= 0); // Null move dynamic reduction based on depth and value - Depth R = (854 + 68 * depth) / 258 + std::min(int(eval - beta) / 192, 3); + Depth R = (793 + 70 * depth) / 252 + std::min(int(eval - beta) / 192, 3); ss->currentMove = MOVE_NULL; ss->continuationHistory = &thisThread->continuationHistory[0][0][NO_PIECE][0]; @@ -898,10 +870,10 @@ namespace { // If we have a good enough capture and a reduced search returns a value // much above beta, we can (almost) safely prune the previous move. if ( !PvNode - && depth >= 5 + && depth > 5 && abs(beta) < VALUE_TB_WIN_IN_MAX_PLY) { - Value raisedBeta = beta + 189 - 45 * improving; + Value raisedBeta = beta + 182 - 48 * improving; assert(raisedBeta < VALUE_INFINITE); MovePicker mp(pos, ttMove, raisedBeta - ss->staticEval, &captureHistory); int probCutCount = 0; @@ -920,7 +892,7 @@ namespace { probCutCount++; ss->currentMove = move; - ss->continuationHistory = &thisThread->continuationHistory[inCheck] + ss->continuationHistory = &thisThread->continuationHistory[ss->inCheck] [captureOrPromotion] [pos.moved_piece(move)] [to_sq(move)]; @@ -932,7 +904,7 @@ namespace { // If the qsearch held, perform the regular search if (value >= raisedBeta) - value = -search(pos, ss+1, -raisedBeta, -raisedBeta+1, depth - 4, !cutNode); + value = -search(pos, ss+1, -raisedBeta, -raisedBeta+1, depth - 5, !cutNode); pos.undo_move(move); @@ -965,10 +937,10 @@ moves_loop: // When in check, search starts from here contHist, countermove, ss->killers, - depth > 12 ? ss->ply : MAX_PLY); + ss->ply); value = bestValue; - singularLMR = moveCountPruning = false; + singularQuietLMR = moveCountPruning = false; ttCapture = ttMove && pos.capture_or_promotion(ttMove); // Mark this node as being searched @@ -1030,15 +1002,16 @@ moves_loop: // When in check, search starts from here // Futility pruning: parent node (~5 Elo) if ( lmrDepth < 6 - && !inCheck - && ss->staticEval + 235 + 172 * lmrDepth <= alpha + && !ss->inCheck + && ss->staticEval + 252 + 176 * lmrDepth <= alpha && (*contHist[0])[movedPiece][to_sq(move)] + (*contHist[1])[movedPiece][to_sq(move)] - + (*contHist[3])[movedPiece][to_sq(move)] < 27400) + + (*contHist[3])[movedPiece][to_sq(move)] + + (*contHist[5])[movedPiece][to_sq(move)] / 2 < 30251) continue; // Prune moves with negative SEE (~20 Elo) - if (!pos.see_ge(move, Value(-(32 - std::min(lmrDepth, 18)) * lmrDepth * lmrDepth))) + if (!pos.see_ge(move, Value(-(31 - std::min(lmrDepth, 18)) * lmrDepth * lmrDepth))) continue; } else @@ -1049,8 +1022,16 @@ moves_loop: // When in check, search starts from here && captureHistory[movedPiece][to_sq(move)][type_of(pos.piece_on(to_sq(move)))] < 0) continue; + // Futility pruning for captures + if ( !givesCheck + && lmrDepth < 6 + && !(PvNode && abs(bestValue) < 2) + && !ss->inCheck + && ss->staticEval + 264 + 397 * lmrDepth + PieceValue[MG][type_of(pos.piece_on(to_sq(move)))] <= alpha) + continue; + // See based pruning - if (!pos.see_ge(move, Value(-194) * depth)) // (~25 Elo) + if (!pos.see_ge(move, Value(-192) * depth)) // (~25 Elo) continue; } } @@ -1081,7 +1062,7 @@ moves_loop: // When in check, search starts from here if (value < singularBeta) { extension = 1; - singularLMR = true; + singularQuietLMR = !ttCapture; } // Multi-cut pruning @@ -1146,7 +1127,7 @@ moves_loop: // When in check, search starts from here // Update the current move (this must be done after singular extension search) ss->currentMove = move; - ss->continuationHistory = &thisThread->continuationHistory[inCheck] + ss->continuationHistory = &thisThread->continuationHistory[ss->inCheck] [captureOrPromotion] [movedPiece] [to_sq(move)]; @@ -1163,12 +1144,12 @@ moves_loop: // When in check, search starts from here || moveCountPruning || ss->staticEval + PieceValue[EG][pos.captured_piece()] <= alpha || cutNode - || thisThread->ttHitAverage < 375 * ttHitAverageResolution * ttHitAverageWindow / 1024)) + || thisThread->ttHitAverage < 399 * TtHitAverageResolution * TtHitAverageWindow / 1024)) { Depth r = reduction(improving, depth, moveCount); // Decrease reduction if the ttHit running average is large - if (thisThread->ttHitAverage > 500 * ttHitAverageResolution * ttHitAverageWindow / 1024) + if (thisThread->ttHitAverage > 492 * TtHitAverageResolution * TtHitAverageWindow / 1024) r--; // Reduction if other threads are searching this position. @@ -1187,7 +1168,7 @@ moves_loop: // When in check, search starts from here r--; // Decrease reduction if ttMove has been singularly extended (~3 Elo) - if (singularLMR) + if (singularQuietLMR) r -= 1 + formerPv; if (!captureOrPromotion) @@ -1214,14 +1195,14 @@ moves_loop: // When in check, search starts from here - 4926; // Decrease/increase reduction by comparing opponent's stat score (~10 Elo) - if (ss->statScore >= -102 && (ss-1)->statScore < -114) + if (ss->statScore >= -99 && (ss-1)->statScore < -116) r--; - else if ((ss-1)->statScore >= -116 && ss->statScore < -154) + else if ((ss-1)->statScore >= -117 && ss->statScore < -150) r++; // Decrease/increase reduction for moves with a good/bad history (~30 Elo) - r -= ss->statScore / 16434; + r -= ss->statScore / 15896; } else { @@ -1365,11 +1346,11 @@ moves_loop: // When in check, search starts from here // must be a mate or a stalemate. If we are in a singular extension search then // return a fail low score. - assert(moveCount || !inCheck || excludedMove || !MoveList(pos).size()); + assert(moveCount || !ss->inCheck || excludedMove || !MoveList(pos).size()); if (!moveCount) bestValue = excludedMove ? alpha - : inCheck ? mated_in(ss->ply) : VALUE_DRAW; + : ss->inCheck ? mated_in(ss->ply) : VALUE_DRAW; else if (bestMove) update_all_stats(pos, ss, bestMove, bestValue, beta, prevSq, @@ -1413,7 +1394,7 @@ moves_loop: // When in check, search starts from here Move ttMove, move, bestMove; Depth ttDepth; Value bestValue, value, ttValue, futilityValue, futilityBase, oldAlpha; - bool ttHit, pvHit, inCheck, givesCheck, captureOrPromotion; + bool ttHit, pvHit, givesCheck, captureOrPromotion; int moveCount; if (PvNode) @@ -1426,20 +1407,20 @@ moves_loop: // When in check, search starts from here Thread* thisThread = pos.this_thread(); (ss+1)->ply = ss->ply + 1; bestMove = MOVE_NONE; - inCheck = pos.checkers(); + ss->inCheck = pos.checkers(); moveCount = 0; // Check for an immediate draw or maximum ply reached if ( pos.is_draw(ss->ply) || ss->ply >= MAX_PLY) - return (ss->ply >= MAX_PLY && !inCheck) ? evaluate(pos) : VALUE_DRAW; + return (ss->ply >= MAX_PLY && !ss->inCheck) ? evaluate(pos) : VALUE_DRAW; assert(0 <= ss->ply && ss->ply < MAX_PLY); // Decide whether or not to include checks: this fixes also the type of // TT entry depth that we are going to use. Note that in qsearch we use // only two types of depth in TT: DEPTH_QS_CHECKS or DEPTH_QS_NO_CHECKS. - ttDepth = inCheck || depth >= DEPTH_QS_CHECKS ? DEPTH_QS_CHECKS + ttDepth = ss->inCheck || depth >= DEPTH_QS_CHECKS ? DEPTH_QS_CHECKS : DEPTH_QS_NO_CHECKS; // Transposition table lookup posKey = pos.key(); @@ -1457,7 +1438,7 @@ moves_loop: // When in check, search starts from here return ttValue; // Evaluate the position statically - if (inCheck) + if (ss->inCheck) { ss->staticEval = VALUE_NONE; bestValue = futilityBase = -VALUE_INFINITE; @@ -1493,7 +1474,7 @@ moves_loop: // When in check, search starts from here if (PvNode && bestValue > alpha) alpha = bestValue; - futilityBase = bestValue + 154; + futilityBase = bestValue + 138; } const PieceToHistory* contHist[] = { (ss-1)->continuationHistory, (ss-2)->continuationHistory, @@ -1520,7 +1501,7 @@ moves_loop: // When in check, search starts from here moveCount++; // Futility pruning - if ( !inCheck + if ( !ss->inCheck && !givesCheck && futilityBase > -VALUE_KNOWN_WIN && !pos.advanced_pawn_push(move)) @@ -1543,7 +1524,7 @@ moves_loop: // When in check, search starts from here } // Don't search moves with negative SEE values - if ( !inCheck && !pos.see_ge(move)) + if ( !ss->inCheck && !pos.see_ge(move)) continue; // Speculative prefetch as early as possible @@ -1557,7 +1538,7 @@ moves_loop: // When in check, search starts from here } ss->currentMove = move; - ss->continuationHistory = &thisThread->continuationHistory[inCheck] + ss->continuationHistory = &thisThread->continuationHistory[ss->inCheck] [captureOrPromotion] [pos.moved_piece(move)] [to_sq(move)]; @@ -1591,7 +1572,7 @@ moves_loop: // When in check, search starts from here // All legal moves have been searched. A special case: If we're in check // and no legal moves were found, it is checkmate. - if (inCheck && bestValue == -VALUE_INFINITE) + if (ss->inCheck && bestValue == -VALUE_INFINITE) return mated_in(ss->ply); // Plies to mate from the root tte->save(posKey, value_to_tt(bestValue, ss->ply), pvHit, @@ -1710,8 +1691,12 @@ 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, 6}) + { + if (ss->inCheck && i > 2) + break; if (is_ok((ss-i)->currentMove)) (*(ss-i)->continuationHistory)[pc][to] << bonus; + } }