From f030a1c592eabfa602ff8560d365e516298363ce Mon Sep 17 00:00:00 2001 From: Muzhen Gaming <61100393+XInTheDark@users.noreply.github.com> Date: Tue, 16 May 2023 21:30:53 +0800 Subject: [PATCH] Search tuning at very long time control Many search parameter changes, tuned (https://tests.stockfishchess.org/tests/view/645e4c67d55cccb2e64220ff) at ~300k games @ VLTC (120+1.2). Failed STC: https://tests.stockfishchess.org/tests/view/6465fcd77968ca827c1410c2 LLR: -2.95 (-2.94,2.94) <0.00,2.00> Total: 33824 W: 8863 L: 9067 D: 15894 Ptnml(0-2): 89, 3833, 9266, 3641, 83 Neutral LTC: https://tests.stockfishchess.org/tests/view/646385ce87f6567dd4df4e37 Elo: -0.48 +-1.2 (95%) LOS: 22.2% Total: 60000 W: 16235 L: 16318 D: 27447 Ptnml(0-2): 27, 5831, 18366, 5750, 26 nElo: -1.08 +-2.8 (95%) PairsRatio: 0.99 Passed VLTC 180+1.8: https://tests.stockfishchess.org/tests/view/646385f787f6567dd4df4e3e LLR: 2.95 (-2.94,2.94) <0.50,2.50> Total: 126448 W: 34704 L: 34258 D: 57486 Ptnml(0-2): 9, 10970, 40825, 11406, 14 Passed VLTC SMP 60+0.6 8thread: https://tests.stockfishchess.org/tests/view/646628de884ce93b65df2ac9 LLR: 2.95 (-2.94,2.94) <0.50,2.50> Total: 59456 W: 16791 L: 16487 D: 26178 Ptnml(0-2): 5, 4473, 20467, 4779, 4 closes https://github.com/official-stockfish/Stockfish/pull/4574 Bench: 3347573 --- src/search.cpp | 94 +++++++++++++++++++++++++------------------------- 1 file changed, 47 insertions(+), 47 deletions(-) diff --git a/src/search.cpp b/src/search.cpp index bc495c0e..429db9a5 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -64,7 +64,7 @@ namespace { // Futility margin Value futility_margin(Depth d, bool improving) { - return Value(154 * (d - improving)); + return Value(148 * (d - improving)); } // Reductions lookup table, initialized at startup @@ -72,7 +72,7 @@ namespace { Depth reduction(bool i, Depth d, int mn, Value delta, Value rootDelta) { int r = Reductions[d] * Reductions[mn]; - return (r + 1449 - int(delta) * 937 / int(rootDelta)) / 1024 + (!i && r > 941); + return (r + 1356 - int(delta) * 983 / int(rootDelta)) / 1024 + (!i && r > 901); } constexpr int futility_move_count(bool improving, Depth depth) { @@ -82,7 +82,7 @@ namespace { // History and stats update bonus, based on depth int stat_bonus(Depth d) { - return std::min(341 * d - 470, 1710); + return std::min(337 * d - 497, 1632); } // Add a small random component to draw evaluations to avoid 3-fold blindness @@ -162,7 +162,7 @@ namespace { void Search::init() { for (int i = 1; i < MAX_MOVES; ++i) - Reductions[i] = int((19.47 + std::log(Threads.size()) / 2) * std::log(i)); + Reductions[i] = int((20.89 + std::log(Threads.size()) / 2) * std::log(i)); } @@ -348,12 +348,12 @@ void Thread::search() { // Reset aspiration window starting size Value prev = rootMoves[pvIdx].averageScore; - delta = Value(10) + int(prev) * prev / 16502; + delta = Value(11) + int(prev) * prev / 15368; alpha = std::max(prev - delta,-VALUE_INFINITE); beta = std::min(prev + delta, VALUE_INFINITE); // Adjust optimism based on root move's previousScore - int opt = 102 * prev / (std::abs(prev) + 147); + int opt = 116 * prev / (std::abs(prev) + 143); optimism[ us] = Value(opt); optimism[~us] = -optimism[us]; @@ -742,7 +742,7 @@ namespace { // Use static evaluation difference to improve quiet move ordering (~4 Elo) if (is_ok((ss-1)->currentMove) && !(ss-1)->inCheck && !priorCapture) { - int bonus = std::clamp(-19 * int((ss-1)->staticEval + ss->staticEval), -1920, 1920); + int bonus = std::clamp(-19 * int((ss-1)->staticEval + ss->staticEval), -1717, 1717); thisThread->mainHistory[~us][from_to((ss-1)->currentMove)] << bonus; } @@ -752,13 +752,13 @@ namespace { // margin and the improving flag are used in various pruning heuristics. improvement = (ss-2)->staticEval != VALUE_NONE ? ss->staticEval - (ss-2)->staticEval : (ss-4)->staticEval != VALUE_NONE ? ss->staticEval - (ss-4)->staticEval - : 156; + : 163; improving = improvement > 0; // Step 7. Razoring (~1 Elo). // If eval is really low check with qsearch if it can exceed alpha, if it can't, // return a fail low. - if (eval < alpha - 426 - 256 * depth * depth) + if (eval < alpha - 467 - 266 * depth * depth) { value = qsearch(pos, ss, alpha - 1, alpha); if (value < alpha) @@ -769,18 +769,18 @@ namespace { // The depth condition is important for mate finding. if ( !ss->ttPv && depth < 9 - && eval - futility_margin(depth, improving) - (ss-1)->statScore / 280 >= beta + && eval - futility_margin(depth, improving) - (ss-1)->statScore / 306 >= beta && eval >= beta - && eval < 25128) // larger than VALUE_KNOWN_WIN, but smaller than TB wins + && eval < 22761) // larger than VALUE_KNOWN_WIN, but smaller than TB wins return eval; // Step 9. Null move search with verification search (~35 Elo) if ( !PvNode && (ss-1)->currentMove != MOVE_NULL - && (ss-1)->statScore < 18755 + && (ss-1)->statScore < 18404 && eval >= beta && eval >= ss->staticEval - && ss->staticEval >= beta - 20 * depth - improvement / 13 + 253 + && ss->staticEval >= beta - 19 * depth - improvement / 13 + 257 && !excludedMove && pos.non_pawn_material(us) && (ss->ply >= thisThread->nmpMinPly)) @@ -823,13 +823,13 @@ namespace { } } - probCutBeta = beta + 186 - 54 * improving; + probCutBeta = beta + 174 - 60 * improving; // Step 10. ProbCut (~10 Elo) // If we have a good enough capture (or queen promotion) and a reduced search returns a value // much above beta, we can (almost) safely prune the previous move. if ( !PvNode - && depth > 4 + && depth > 3 && abs(beta) < VALUE_TB_WIN_IN_MAX_PLY // if value from transposition table is lower than probCutBeta, don't attempt probCut // there and in further interactions with transposition table cutoff depth is set to depth - 3 @@ -887,20 +887,20 @@ namespace { return qsearch(pos, ss, alpha, beta); if ( cutNode - && depth >= 7 + && depth >= 8 && !ttMove) depth -= 2; moves_loop: // When in check, search starts here // Step 12. A small Probcut idea, when we are in check (~4 Elo) - probCutBeta = beta + 391; + probCutBeta = beta + 430; if ( ss->inCheck && !PvNode && depth >= 2 && ttCapture && (tte->bound() & BOUND_LOWER) - && tte->depth() >= depth - 3 + && tte->depth() >= depth - 4 && ttValue >= probCutBeta && abs(ttValue) <= VALUE_KNOWN_WIN && abs(beta) <= VALUE_KNOWN_WIN) @@ -986,15 +986,15 @@ moves_loop: // When in check, search starts here { // Futility pruning for captures (~2 Elo) if ( !givesCheck - && lmrDepth < 6 + && lmrDepth < 7 && !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) + && ss->staticEval + 207 + 223 * lmrDepth + PieceValue[EG][pos.piece_on(to_sq(move))] + + captureHistory[movedPiece][to_sq(move)][type_of(pos.piece_on(to_sq(move)))] * 1078 / 7000 < alpha) continue; Bitboard occupied; // SEE based pruning (~11 Elo) - if (!pos.see_ge(move, occupied, Value(-206) * depth)) + if (!pos.see_ge(move, occupied, Value(-205) * depth)) { if (depth < 2 - capture) continue; @@ -1022,24 +1022,24 @@ moves_loop: // When in check, search starts here // Continuation history based pruning (~2 Elo) if ( lmrDepth < 5 - && history < -4405 * (depth - 1)) + && history < -3792 * (depth - 1)) continue; history += 2 * thisThread->mainHistory[us][from_to(move)]; - lmrDepth += history / 7278; + lmrDepth += history / 7019; lmrDepth = std::max(lmrDepth, -2); // Futility pruning: parent node (~13 Elo) if ( !ss->inCheck - && lmrDepth < 13 - && ss->staticEval + 103 + 138 * lmrDepth <= alpha) + && lmrDepth < 12 + && ss->staticEval + 111 + 136 * lmrDepth <= alpha) continue; lmrDepth = std::max(lmrDepth, 0); // Prune moves with negative SEE (~4 Elo) - if (!pos.see_ge(move, Value(-24 * lmrDepth * lmrDepth - 16 * lmrDepth))) + if (!pos.see_ge(move, Value(-27 * lmrDepth * lmrDepth - 33 * lmrDepth / 2))) continue; } } @@ -1054,7 +1054,7 @@ moves_loop: // When in check, search starts here // a reduced search on all the other moves but the ttMove and if the // result is lower than ttValue minus a margin, then we will extend the ttMove. if ( !rootNode - && depth >= 4 - (thisThread->completedDepth > 21) + 2 * (PvNode && tte->is_pv()) + && depth >= 4 - (thisThread->completedDepth > 22) + 2 * (PvNode && tte->is_pv()) && move == ttMove && !excludedMove // Avoid recursive singular search /* && ttValue != VALUE_NONE Already implicit in the next condition */ @@ -1062,7 +1062,7 @@ moves_loop: // When in check, search starts here && (tte->bound() & BOUND_LOWER) && tte->depth() >= depth - 3) { - Value singularBeta = ttValue - (3 + 2 * (ss->ttPv && !PvNode)) * depth / 2; + Value singularBeta = ttValue - (99 + 65 * (ss->ttPv && !PvNode)) * depth / 64; Depth singularDepth = (depth - 1) / 2; ss->excludedMove = move; @@ -1076,8 +1076,8 @@ moves_loop: // When in check, search starts here // Avoid search explosion by limiting the number of double extensions if ( !PvNode - && value < singularBeta - 25 - && ss->doubleExtensions <= 10) + && value < singularBeta - 22 + && ss->doubleExtensions <= 11) { extension = 2; depth += depth < 13; @@ -1107,15 +1107,15 @@ moves_loop: // When in check, search starts here // Check extensions (~1 Elo) else if ( givesCheck - && depth > 10 - && abs(ss->staticEval) > 88) + && depth > 9 + && abs(ss->staticEval) > 87) extension = 1; // Quiet ttMove extensions (~1 Elo) else if ( PvNode && move == ttMove && move == ss->killers[0] - && (*contHist[0])[movedPiece][to_sq(move)] >= 5705) + && (*contHist[0])[movedPiece][to_sq(move)] >= 5480) extension = 1; } @@ -1144,7 +1144,7 @@ moves_loop: // When in check, search starts here r -= cutNode && tte->depth() >= depth + 3 ? 3 : 2; // Decrease reduction if opponent's move count is high (~1 Elo) - if ((ss-1)->moveCount > 7) + if ((ss-1)->moveCount > 8) r--; // Increase reduction for cut nodes (~3 Elo) @@ -1157,7 +1157,7 @@ moves_loop: // When in check, search starts here // Decrease reduction for PvNodes based on depth (~2 Elo) if (PvNode) - r -= 1 + 12 / (3 + depth); + r -= 1 + 11 / (3 + depth); // Decrease reduction if ttMove has been singularly extended (~1 Elo) if (singularQuietLMR) @@ -1174,10 +1174,10 @@ moves_loop: // When in check, search starts here + (*contHist[0])[movedPiece][to_sq(move)] + (*contHist[1])[movedPiece][to_sq(move)] + (*contHist[3])[movedPiece][to_sq(move)] - - 4082; + - 3755; // Decrease/increase reduction for moves with a good/bad history (~25 Elo) - r -= ss->statScore / (11079 + 4626 * (depth > 6 && depth < 19)); + r -= ss->statScore / (10445 + 4762 * (depth > 6 && depth < 21)); // Step 17. Late moves reduction / extension (LMR, ~117 Elo) // We use various heuristics for the sons of a node after the first son has @@ -1201,8 +1201,8 @@ moves_loop: // When in check, search starts here { // Adjust full depth search based on LMR results - if result // was good enough search deeper, if it was bad enough search shallower - const bool doDeeperSearch = value > (bestValue + 68 + 12 * (newDepth - d)); - const bool doEvenDeeperSearch = value > alpha + 588 && ss->doubleExtensions <= 5; + const bool doDeeperSearch = value > (bestValue + 63 + 11 * (newDepth - d)); + const bool doEvenDeeperSearch = value > alpha + 662 && ss->doubleExtensions <= 6; const bool doShallowerSearch = value < bestValue + newDepth; ss->doubleExtensions = ss->doubleExtensions + doEvenDeeperSearch; @@ -1227,7 +1227,7 @@ moves_loop: // When in check, search starts here if (!ttMove && cutNode) r += 2; - value = -search(pos, ss+1, -(alpha+1), -alpha, newDepth - (r > 4), !cutNode); + value = -search(pos, ss+1, -(alpha+1), -alpha, newDepth - (r > 3), !cutNode); } // For PV nodes only, do a full PV search on the first move or after a fail @@ -1320,8 +1320,8 @@ moves_loop: // When in check, search starts here { // Reduce other moves if we have found at least one score improvement (~1 Elo) if ( depth > 1 - && beta < 12535 - && value > -12535) + && beta < 14001 + && value > -12754) depth -= 1; assert(depth > 0); @@ -1370,7 +1370,7 @@ moves_loop: // When in check, search starts here // Bonus for prior countermove that caused the fail low else if (!priorCapture && prevSq != SQ_NONE) { - int bonus = (depth > 5) + (PvNode || cutNode) + (bestValue < alpha - 97 * depth) + ((ss-1)->moveCount > 10); + int bonus = (depth > 5) + (PvNode || cutNode) + (bestValue < alpha - 100 * depth) + ((ss-1)->moveCount > 11); update_continuation_histories(ss-1, pos.piece_on(prevSq), prevSq, stat_bonus(depth) * bonus); } @@ -1499,7 +1499,7 @@ moves_loop: // When in check, search starts here if (PvNode && bestValue > alpha) alpha = bestValue; - futilityBase = bestValue + 168; + futilityBase = bestValue + 190; } const PieceToHistory* contHist[] = { (ss-1)->continuationHistory, (ss-2)->continuationHistory, @@ -1572,7 +1572,7 @@ moves_loop: // When in check, search starts here continue; // Do not search moves with bad enough SEE values (~5 Elo) - if (!pos.see_ge(move, Value(-110))) + if (!pos.see_ge(move, Value(-94))) continue; } @@ -1705,7 +1705,7 @@ moves_loop: // When in check, search starts here if (!pos.capture_stage(bestMove)) { - int bonus2 = bestValue > beta + 153 ? bonus1 // larger bonus + int bonus2 = bestValue > beta + 143 ? bonus1 // larger bonus : stat_bonus(depth); // smaller bonus // Increase stats for the best move in case it was a quiet move -- 2.39.2