X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=671ac489e82ff595230697eba689f6c77546f08f;hp=a3d4a329a1f7c4075f68e7e5261104d679cbbffc;hb=208c53df0fc289466def7deae58f687957efb734;hpb=bb5589b829b79d7c60a820d4b1634dccbc4bbb3f diff --git a/src/search.cpp b/src/search.cpp index a3d4a329..671ac489 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 = 527; Value futility_margin(Depth d, bool improving) { - return Value(217 * (d - improving)); + return Value(227 * (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 + 570) / 1024 + (!i && r > 1018); } 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 ? 27 : 17 * d * d + 133 * d - 134; } // Add a small random component to draw evaluations to avoid 3fold-blindness @@ -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 @@ -434,12 +403,12 @@ void Thread::search() { if (rootDepth >= 4) { Value prev = rootMoves[pvIdx].previousScore; - delta = Value(21); + delta = Value(19); alpha = std::max(prev - delta,-VALUE_INFINITE); 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 + (110 - ct / 2) * prev / (abs(prev) + 140); 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 = (296 + 6 * (mainThread->bestPreviousScore - bestValue) + + 6 * (mainThread->iterValue[iterIdx] - bestValue)) / 725.0; 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 ? 1.92 : 0.95; + double reduction = (1.47 + mainThread->previousTimeReduction) / (2.22 * 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 * 0.56) Threads.increaseDepth = false; else Threads.increaseDepth = true; @@ -627,7 +598,8 @@ namespace { Depth extension, newDepth; Value bestValue, value, ttValue, eval, maxValue; bool ttHit, ttPv, formerPv, givesCheck, improving, didLMR, priorCapture; - bool captureOrPromotion, doFullDepthSearch, moveCountPruning, ttCapture, singularLMR; + bool captureOrPromotion, doFullDepthSearch, moveCountPruning, + ttCapture, singularQuietLMR; Piece movedPiece; int moveCount, captureCount, quietCount; @@ -690,7 +662,7 @@ namespace { // search to overwrite a previous full search TT value, so we use a different // position key in case of an excluded move. excludedMove = ss->excludedMove; - posKey = pos.key() ^ Key(excludedMove << 16); // Isn't a very good hash + posKey = pos.key() ^ (Key(excludedMove) << 48); // Isn't a very good hash tte = TT.probe(posKey, ttHit); ttValue = ttHit ? value_from_tt(tte->value(), ss->ply, pos.rule50_count()) : VALUE_NONE; ttMove = rootNode ? thisThread->rootMoves[thisThread->pvIdx].pv[0] @@ -698,12 +670,12 @@ namespace { ttPv = PvNode || (ttHit && tte->is_pv()); formerPv = ttPv && !PvNode; - if (ttPv && depth > 12 && ss->ply - 1 < MAX_LPH && !pos.captured_piece() && is_ok((ss-1)->currentMove)) + if (ttPv && depth > 12 && ss->ply - 1 < MAX_LPH && !priorCapture && 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; + thisThread->ttHitAverage = (TtHitAverageWindow - 1) * thisThread->ttHitAverage / TtHitAverageWindow + + TtHitAverageResolution * ttHit; // At non-PV nodes we check for an early TT cutoff if ( !PvNode @@ -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 < 23824 && eval >= beta && eval >= ss->staticEval - && ss->staticEval >= beta - 32 * depth - 30 * improving + 120 * ttPv + 292 + && ss->staticEval >= beta - 33 * depth - 33 * improving + 112 * ttPv + 311 && !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 = (737 + 77 * depth) / 246 + 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 > 4 && abs(beta) < VALUE_TB_WIN_IN_MAX_PLY) { - Value raisedBeta = beta + 189 - 45 * improving; + Value raisedBeta = beta + 176 - 49 * improving; assert(raisedBeta < VALUE_INFINITE); MovePicker mp(pos, ttMove, raisedBeta - ss->staticEval, &captureHistory); int probCutCount = 0; @@ -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 @@ -1031,14 +1003,15 @@ moves_loop: // When in check, search starts from here // Futility pruning: parent node (~5 Elo) if ( lmrDepth < 6 && !ss->inCheck - && ss->staticEval + 235 + 172 * lmrDepth <= alpha + && ss->staticEval + 284 + 188 * 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 < 28388) 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(-(29 - std::min(lmrDepth, 17)) * lmrDepth * lmrDepth))) continue; } else @@ -1049,8 +1022,17 @@ 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) + && PieceValue[MG][type_of(movedPiece)] >= PieceValue[MG][type_of(pos.piece_on(to_sq(move)))] + && !ss->inCheck + && ss->staticEval + 267 + 391 * 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(-202) * depth)) // (~25 Elo) continue; } } @@ -1081,7 +1063,7 @@ moves_loop: // When in check, search starts from here if (value < singularBeta) { extension = 1; - singularLMR = true; + singularQuietLMR = !ttCapture; } // Multi-cut pruning @@ -1163,12 +1145,12 @@ 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 < 415 * 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 > 473 * TtHitAverageResolution * TtHitAverageWindow / 1024) r--; // Reduction if other threads are searching this position. @@ -1183,11 +1165,11 @@ moves_loop: // When in check, search starts from here r++; // Decrease reduction if opponent's move count is high (~5 Elo) - if ((ss-1)->moveCount > 14) + if ((ss-1)->moveCount > 13) r--; // Decrease reduction if ttMove has been singularly extended (~3 Elo) - if (singularLMR) + if (singularQuietLMR) r -= 1 + formerPv; if (!captureOrPromotion) @@ -1205,23 +1187,23 @@ moves_loop: // When in check, search starts from here // hence break make_move(). (~2 Elo) else if ( type_of(move) == NORMAL && !pos.see_ge(reverse_move(move))) - r -= 2 + ttPv; + r -= 2 + ttPv - (type_of(movedPiece) == PAWN); ss->statScore = thisThread->mainHistory[us][from_to(move)] + (*contHist[0])[movedPiece][to_sq(move)] + (*contHist[1])[movedPiece][to_sq(move)] + (*contHist[3])[movedPiece][to_sq(move)] - - 4926; + - 4826; // Decrease/increase reduction by comparing opponent's stat score (~10 Elo) - if (ss->statScore >= -102 && (ss-1)->statScore < -114) + if (ss->statScore >= -100 && (ss-1)->statScore < -112) r--; - else if ((ss-1)->statScore >= -116 && ss->statScore < -154) + else if ((ss-1)->statScore >= -125 && ss->statScore < -138) r++; // Decrease/increase reduction for moves with a good/bad history (~30 Elo) - r -= ss->statScore / 16434; + r -= ss->statScore / 14615; } else { @@ -1231,7 +1213,7 @@ moves_loop: // When in check, search starts from here // Unless giving check, this capture is likely bad if ( !givesCheck - && ss->staticEval + PieceValue[EG][pos.captured_piece()] + 200 * depth <= alpha) + && ss->staticEval + PieceValue[EG][pos.captured_piece()] + 211 * depth <= alpha) r++; } @@ -1493,7 +1475,7 @@ moves_loop: // When in check, search starts from here if (PvNode && bestValue > alpha) alpha = bestValue; - futilityBase = bestValue + 154; + futilityBase = bestValue + 141; } const PieceToHistory* contHist[] = { (ss-1)->continuationHistory, (ss-2)->continuationHistory, @@ -1743,8 +1725,8 @@ moves_loop: // When in check, search starts from here 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); + if (depth > 11 && ss->ply < MAX_LPH) + thisThread->lowPlyHistory[ss->ply][from_to(move)] << stat_bonus(depth - 6); } // When playing with strength handicap, choose best move among a set of RootMoves