X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Fsearch.cpp;h=d0ed44fa16a8c34ebc5e1648bd93ff6b580f558c;hb=fc5b59b88bae00b7e74bbad0de7c3c33136937cf;hp=cd7369c862338c956d9b10471083efd055ec4d37;hpb=5eeb96d0e7d54686376305029c477c42478aa1d5;p=stockfish diff --git a/src/search.cpp b/src/search.cpp index cd7369c8..d0ed44fa 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -1,6 +1,6 @@ /* Stockfish, a UCI chess playing engine derived from Glaurung 2.1 - Copyright (C) 2004-2022 The Stockfish developers (see AUTHORS file) + Copyright (C) 2004-2023 The Stockfish developers (see AUTHORS file) Stockfish is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -63,7 +63,7 @@ namespace { // Futility margin Value futility_margin(Depth d, bool improving) { - return Value(174 * (d - improving)); + return Value(158 * (d - improving)); } // Reductions lookup table, initialized at startup @@ -71,7 +71,7 @@ namespace { Depth reduction(bool i, Depth d, int mn, Value delta, Value rootDelta) { int r = Reductions[d] * Reductions[mn]; - return (r + 1463 - int(delta) * 1024 / int(rootDelta)) / 1024 + (!i && r > 1010); + return (r + 1460 - int(delta) * 1024 / int(rootDelta)) / 1024 + (!i && r > 937); } constexpr int futility_move_count(bool improving, Depth depth) { @@ -81,7 +81,7 @@ namespace { // History and stats update bonus, based on depth int stat_bonus(Depth d) { - return std::min((8 * d + 240) * d - 276 , 1907); + return std::min((11 * d + 284) * d - 363 , 1650); } // Add a small random component to draw evaluations to avoid 3-fold blindness @@ -158,7 +158,7 @@ namespace { void Search::init() { for (int i = 1; i < MAX_MOVES; ++i) - Reductions[i] = int((20.81 + std::log(Threads.size()) / 2) * std::log(i)); + Reductions[i] = int((20.26 + std::log(Threads.size()) / 2) * std::log(i)); } @@ -244,7 +244,7 @@ void MainThread::search() { // Send again PV info if we have a new best thread if (bestThread != this) - sync_cout << UCI::pv(bestThread->rootPos, bestThread->completedDepth, -VALUE_INFINITE, VALUE_INFINITE) << sync_endl; + sync_cout << UCI::pv(bestThread->rootPos, bestThread->completedDepth) << sync_endl; sync_cout << "bestmove " << UCI::move(bestThread->rootMoves[0].pv[0], rootPos.is_chess960()); @@ -307,11 +307,9 @@ void Thread::search() { multiPV = std::min(multiPV, rootMoves.size()); - complexityAverage.set(174, 1); + complexityAverage.set(153, 1); - trend = SCORE_ZERO; - optimism[ us] = Value(39); - optimism[~us] = -optimism[us]; + optimism[us] = optimism[~us] = VALUE_ZERO; int searchAgainCounter = 0; @@ -353,16 +351,12 @@ void Thread::search() { if (rootDepth >= 4) { Value prev = rootMoves[pvIdx].averageScore; - delta = Value(16) + int(prev) * prev / 19178; + delta = Value(10) + int(prev) * prev / 15400; alpha = std::max(prev - delta,-VALUE_INFINITE); beta = std::min(prev + delta, VALUE_INFINITE); - // Adjust trend and optimism based on root move's previousScore - int tr = sigmoid(prev, 3, 8, 90, 125, 1); - trend = (us == WHITE ? make_score(tr, tr / 2) - : -make_score(tr, tr / 2)); - - int opt = sigmoid(prev, 8, 17, 144, 15012, 183); + // Adjust optimism based on root move's previousScore + int opt = 116 * prev / (std::abs(prev) + 170); optimism[ us] = Value(opt); optimism[~us] = -optimism[us]; } @@ -398,7 +392,7 @@ void Thread::search() { && multiPV == 1 && (bestValue <= alpha || bestValue >= beta) && Time.elapsed() > 3000) - sync_cout << UCI::pv(rootPos, rootDepth, alpha, beta) << sync_endl; + sync_cout << UCI::pv(rootPos, rootDepth) << sync_endl; // In case of failing low/high increase aspiration window and // re-search, otherwise exit the loop. @@ -429,7 +423,7 @@ void Thread::search() { if ( mainThread && (Threads.stop || pvIdx + 1 == multiPV || Time.elapsed() > 3000)) - sync_cout << UCI::pv(rootPos, rootDepth, alpha, beta) << sync_endl; + sync_cout << UCI::pv(rootPos, rootDepth) << sync_endl; } if (!Threads.stop) @@ -465,16 +459,16 @@ void Thread::search() { && !Threads.stop && !mainThread->stopOnPonderhit) { - double fallingEval = (69 + 12 * (mainThread->bestPreviousAverageScore - bestValue) - + 6 * (mainThread->iterValue[iterIdx] - bestValue)) / 781.4; + double fallingEval = (71 + 12 * (mainThread->bestPreviousAverageScore - bestValue) + + 6 * (mainThread->iterValue[iterIdx] - bestValue)) / 656.7; fallingEval = std::clamp(fallingEval, 0.5, 1.5); // If the bestMove is stable over several iterations, reduce time accordingly - timeReduction = lastBestMoveDepth + 10 < completedDepth ? 1.63 : 0.73; - double reduction = (1.56 + mainThread->previousTimeReduction) / (2.20 * timeReduction); + timeReduction = lastBestMoveDepth + 9 < completedDepth ? 1.37 : 0.65; + double reduction = (1.4 + mainThread->previousTimeReduction) / (2.15 * timeReduction); double bestMoveInstability = 1 + 1.7 * totBestMoveChanges / Threads.size(); int complexity = mainThread->complexityAverage.value(); - double complexPosition = std::min(1.0 + (complexity - 277) / 1819.1, 1.5); + double complexPosition = std::min(1.0 + (complexity - 261) / 1738.7, 1.5); double totalTime = Time.optimum() * fallingEval * reduction * bestMoveInstability * complexPosition; @@ -493,12 +487,11 @@ void Thread::search() { else Threads.stop = true; } - else if ( Threads.increaseDepth - && !mainThread->ponder - && Time.elapsed() > totalTime * 0.43) - Threads.increaseDepth = false; + else if ( !mainThread->ponder + && Time.elapsed() > totalTime * 0.53) + Threads.increaseDepth = false; else - Threads.increaseDepth = true; + Threads.increaseDepth = true; } mainThread->iterValue[iterIdx] = bestValue; @@ -640,16 +633,16 @@ namespace { && ttValue != VALUE_NONE // Possible in case of TT access race && (tte->bound() & (ttValue >= beta ? BOUND_LOWER : BOUND_UPPER))) { - // If ttMove is quiet, update move sorting heuristics on TT hit (~1 Elo) + // If ttMove is quiet, update move sorting heuristics on TT hit (~2 Elo) if (ttMove) { if (ttValue >= beta) { - // Bonus for a quiet ttMove that fails high (~3 Elo) + // Bonus for a quiet ttMove that fails high (~2 Elo) if (!ttCapture) update_quiet_stats(pos, ss, ttMove, stat_bonus(depth)); - // Extra penalty for early quiet moves of the previous ply (~0 Elo) + // Extra penalty for early quiet moves of the previous ply (~0 Elo on STC, ~2 Elo on LTC) if ((ss-1)->moveCount <= 2 && !priorCapture) update_continuation_histories(ss-1, pos.piece_on(prevSq), prevSq, -stat_bonus(depth + 1)); } @@ -741,7 +734,7 @@ namespace { else // Fall back to (semi)classical complexity for TT hits, the NNUE complexity is lost complexity = abs(ss->staticEval - pos.psq_eg_stm()); - // ttValue can be used as a better position evaluation (~4 Elo) + // ttValue can be used as a better position evaluation (~7 Elo) if ( ttValue != VALUE_NONE && (tte->bound() & (ttValue > eval ? BOUND_LOWER : BOUND_UPPER))) eval = ttValue; @@ -757,10 +750,10 @@ namespace { thisThread->complexityAverage.update(complexity); - // Use static evaluation difference to improve quiet move ordering (~3 Elo) + // 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(-16 * int((ss-1)->staticEval + ss->staticEval), -2000, 2000); + int bonus = std::clamp(-19 * int((ss-1)->staticEval + ss->staticEval), -1940, 1940); thisThread->mainHistory[~us][from_to((ss-1)->currentMove)] << bonus; } @@ -770,37 +763,35 @@ 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 - : 175; + : 172; improving = improvement > 0; - // Step 7. Razoring. + // 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 ( !PvNode - && depth <= 7 - && eval < alpha - 341 - 267 * depth * depth) + if (eval < alpha - 394 - 255 * depth * depth) { value = qsearch(pos, ss, alpha - 1, alpha); if (value < alpha) return value; } - // Step 8. Futility pruning: child node (~25 Elo). + // Step 8. Futility pruning: child node (~40 Elo). // The depth condition is important for mate finding. if ( !ss->ttPv && depth < 8 - && eval - futility_margin(depth, improving) - (ss-1)->statScore / 256 >= beta + && eval - futility_margin(depth, improving) - (ss-1)->statScore / 304 >= beta && eval >= beta - && eval < 26305) // larger than VALUE_KNOWN_WIN, but smaller than TB wins. + && eval < 28580) // larger than VALUE_KNOWN_WIN, but smaller than TB wins return eval; - // Step 9. Null move search with verification search (~22 Elo) + // Step 9. Null move search with verification search (~35 Elo) if ( !PvNode && (ss-1)->currentMove != MOVE_NULL - && (ss-1)->statScore < 15344 + && (ss-1)->statScore < 18200 && eval >= beta && eval >= ss->staticEval - && ss->staticEval >= beta - 15 * depth - improvement / 15 + 201 + complexity / 24 + && ss->staticEval >= beta - 20 * depth - improvement / 14 + 235 + complexity / 24 && !excludedMove && pos.non_pawn_material(us) && (ss->ply >= thisThread->nmpMinPly || us != thisThread->nmpColor)) @@ -808,7 +799,7 @@ namespace { assert(eval - beta >= 0); // Null move dynamic reduction based on depth, eval and complexity of position - Depth R = std::min(int(eval - beta) / 152, 5) + depth / 3 + 4 - (complexity > 650); + Depth R = std::min(int(eval - beta) / 165, 6) + depth / 3 + 4 - (complexity > 800); ss->currentMove = MOVE_NULL; ss->continuationHistory = &thisThread->continuationHistory[0][0][NO_PIECE][0]; @@ -844,9 +835,9 @@ namespace { } } - probCutBeta = beta + 173 - 46 * improving; + probCutBeta = beta + 180 - 54 * improving; - // Step 10. ProbCut (~4 Elo) + // Step 10. ProbCut (~10 Elo) // 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 @@ -863,7 +854,7 @@ namespace { { assert(probCutBeta < VALUE_INFINITE); - MovePicker mp(pos, ttMove, probCutBeta - ss->staticEval, depth - 3, &captureHistory); + MovePicker mp(pos, ttMove, probCutBeta - ss->staticEval, &captureHistory); while ((move = mp.next_move()) != MOVE_NONE) if (move != excludedMove && pos.legal(move)) @@ -897,7 +888,7 @@ namespace { } // Step 11. If the position is not in TT, decrease depth by 3. - // Use qsearch if depth is equal or below zero (~4 Elo) + // Use qsearch if depth is equal or below zero (~9 Elo) if ( PvNode && !ttMove) depth -= 3; @@ -912,8 +903,8 @@ namespace { moves_loop: // When in check, search starts here - // Step 12. A small Probcut idea, when we are in check (~0 Elo) - probCutBeta = beta + 481; + // Step 12. A small Probcut idea, when we are in check (~4 Elo) + probCutBeta = beta + 402; if ( ss->inCheck && !PvNode && depth >= 2 @@ -989,12 +980,12 @@ moves_loop: // When in check, search starts here Value delta = beta - alpha; - // Step 14. Pruning at shallow depth (~98 Elo). Depth conditions are important for mate finding. + // Step 14. Pruning at shallow depth (~120 Elo). Depth conditions are important for mate finding. if ( !rootNode && pos.non_pawn_material(us) && bestValue > VALUE_TB_LOSS_IN_MAX_PLY) { - // Skip quiet moves if movecount exceeds our FutilityMoveCount threshold (~7 Elo) + // Skip quiet moves if movecount exceeds our FutilityMoveCount threshold (~8 Elo) moveCountPruning = moveCount >= futility_move_count(improving, depth); // Reduced depth of the next LMR search @@ -1003,18 +994,17 @@ moves_loop: // When in check, search starts here if ( capture || givesCheck) { - // Futility pruning for captures (~0 Elo) - if ( !pos.empty(to_sq(move)) - && !givesCheck + // Futility pruning for captures (~2 Elo) + if ( !givesCheck && !PvNode - && lmrDepth < 6 + && lmrDepth < 7 && !ss->inCheck - && ss->staticEval + 277 + 187 * lmrDepth + PieceValue[EG][pos.piece_on(to_sq(move))] + && ss->staticEval + 185 + 203 * lmrDepth + PieceValue[EG][pos.piece_on(to_sq(move))] + captureHistory[movedPiece][to_sq(move)][type_of(pos.piece_on(to_sq(move)))] / 6 < alpha) continue; - // SEE based pruning (~9 Elo) - if (!pos.see_ge(move, Value(-203) * depth)) + // SEE based pruning (~11 Elo) + if (!pos.see_ge(move, Value(-220) * depth)) continue; } else @@ -1025,34 +1015,34 @@ moves_loop: // When in check, search starts here // Continuation history based pruning (~2 Elo) if ( lmrDepth < 5 - && history < -3875 * (depth - 1)) + && history < -4180 * (depth - 1)) continue; history += 2 * thisThread->mainHistory[us][from_to(move)]; - // Futility pruning: parent node (~9 Elo) + // Futility pruning: parent node (~13 Elo) if ( !ss->inCheck - && lmrDepth < 11 - && ss->staticEval + 122 + 138 * lmrDepth + history / 60 <= alpha) + && lmrDepth < 13 + && ss->staticEval + 103 + 136 * lmrDepth + history / 53 <= alpha) continue; - // Prune moves with negative SEE (~3 Elo) - if (!pos.see_ge(move, Value(-25 * lmrDepth * lmrDepth - 20 * lmrDepth))) + // Prune moves with negative SEE (~4 Elo) + if (!pos.see_ge(move, Value(-25 * lmrDepth * lmrDepth - 16 * lmrDepth))) continue; } } - // Step 15. Extensions (~66 Elo) + // Step 15. Extensions (~100 Elo) // We take care to not overdo to avoid search getting stuck. if (ss->ply < thisThread->rootDepth * 2) { - // Singular extension search (~58 Elo). If all moves but one fail low on a + // Singular extension search (~94 Elo). If all moves but one fail low on a // search of (alpha-s, beta-s), and just one fails high on (alpha, beta), // then that move is singular and should be extended. To verify this we do // 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->previousDepth > 27) + 2 * (PvNode && tte->is_pv()) + && depth >= 4 - (thisThread->previousDepth > 24) + 2 * (PvNode && tte->is_pv()) && move == ttMove && !excludedMove // Avoid recursive singular search /* && ttValue != VALUE_NONE Already implicit in the next condition */ @@ -1060,7 +1050,7 @@ moves_loop: // When in check, search starts here && (tte->bound() & BOUND_LOWER) && tte->depth() >= depth - 3) { - Value singularBeta = ttValue - 3 * depth; + Value singularBeta = ttValue - (3 + (ss->ttPv && !PvNode)) * depth; Depth singularDepth = (depth - 1) / 2; ss->excludedMove = move; @@ -1074,9 +1064,12 @@ moves_loop: // When in check, search starts here // Avoid search explosion by limiting the number of double extensions if ( !PvNode - && value < singularBeta - 26 - && ss->doubleExtensions <= 8) + && value < singularBeta - 25 + && ss->doubleExtensions <= 10) + { extension = 2; + depth += depth < 12; + } } // Multi-cut pruning @@ -1099,14 +1092,14 @@ moves_loop: // When in check, search starts here // Check extensions (~1 Elo) else if ( givesCheck && depth > 9 - && abs(ss->staticEval) > 71) + && abs(ss->staticEval) > 78) extension = 1; - // Quiet ttMove extensions (~0 Elo) + // Quiet ttMove extensions (~1 Elo) else if ( PvNode && move == ttMove && move == ss->killers[0] - && (*contHist[0])[movedPiece][to_sq(move)] >= 5491) + && (*contHist[0])[movedPiece][to_sq(move)] >= 5600) extension = 1; } @@ -1127,57 +1120,62 @@ moves_loop: // When in check, search starts here // Step 16. Make the move pos.do_move(move, st, givesCheck); - // Step 17. Late moves reduction / extension (LMR, ~98 Elo) - // We use various heuristics for the sons of a node after the first son has - // been searched. In general we would like to reduce them, but there are many - // cases where we extend a son if it has good chances to be "interesting". - if ( depth >= 2 - && moveCount > 1 + (PvNode && ss->ply <= 1) - && ( !ss->ttPv - || !capture - || (cutNode && (ss-1)->moveCount > 1))) - { - Depth r = reduction(improving, depth, moveCount, delta, thisThread->rootDelta); + Depth r = reduction(improving, depth, moveCount, delta, thisThread->rootDelta); - // Decrease reduction if position is or has been on the PV - // and node is not likely to fail low. (~3 Elo) - if ( ss->ttPv - && !likelyFailLow) - r -= 2; + // Decrease reduction if position is or has been on the PV + // and node is not likely to fail low. (~3 Elo) + if ( ss->ttPv + && !likelyFailLow) + r -= 2; - // Decrease reduction if opponent's move count is high (~1 Elo) - if ((ss-1)->moveCount > 7) - r--; + // Decrease reduction if opponent's move count is high (~1 Elo) + if ((ss-1)->moveCount > 7) + r--; - // Increase reduction for cut nodes (~3 Elo) - if (cutNode) - r += 2; + // Increase reduction for cut nodes (~3 Elo) + if (cutNode) + r += 2; - // Increase reduction if ttMove is a capture (~3 Elo) - if (ttCapture) - r++; + // Increase reduction if ttMove is a capture (~3 Elo) + if (ttCapture) + r++; + + // Decrease reduction for PvNodes based on depth + if (PvNode) + r -= 1 + 11 / (3 + depth); - // Decrease reduction for PvNodes based on depth - if (PvNode) - r -= 1 + 15 / (3 + depth); + // Decrease reduction if ttMove has been singularly extended (~1 Elo) + if (singularQuietLMR) + r--; - // Decrease reduction if ttMove has been singularly extended (~1 Elo) - 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 else reset count to 0 - if ((ss+1)->cutoffCnt > 3 && !PvNode) - r++; + // Increase reduction if next ply has a lot of fail high + if ((ss+1)->cutoffCnt > 3) + r++; - ss->statScore = 2 * thisThread->mainHistory[us][from_to(move)] - + (*contHist[0])[movedPiece][to_sq(move)] - + (*contHist[1])[movedPiece][to_sq(move)] - + (*contHist[3])[movedPiece][to_sq(move)] - - 4560; + ss->statScore = 2 * thisThread->mainHistory[us][from_to(move)] + + (*contHist[0])[movedPiece][to_sq(move)] + + (*contHist[1])[movedPiece][to_sq(move)] + + (*contHist[3])[movedPiece][to_sq(move)] + - 4467; - // Decrease/increase reduction for moves with a good/bad history (~30 Elo) - r -= ss->statScore / 15914; + // Decrease/increase reduction for moves with a good/bad history (~30 Elo) + r -= ss->statScore / (12800 + 4410 * (depth > 7 && depth < 19)); + // Step 17. Late moves reduction / extension (LMR, ~117 Elo) + // We use various heuristics for the sons of a node after the first son has + // been searched. In general we would like to reduce them, but there are many + // cases where we extend a son if it has good chances to be "interesting". + if ( depth >= 2 + && moveCount > 1 + (PvNode && ss->ply <= 1) + && ( !ss->ttPv + || !capture + || (cutNode && (ss-1)->moveCount > 1))) + { // In general we want to cap the LMR depth search at newDepth, but when // reduction is negative, we allow this move a limited search extension // beyond the first move depth. This may lead to hidden double extensions. @@ -1188,8 +1186,18 @@ moves_loop: // When in check, search starts here // Do full depth search when reduced LMR search fails high if (value > alpha && d < newDepth) { - const bool doDeeperSearch = value > (alpha + 73 + 12 * (newDepth - d)); - value = -search(pos, ss+1, -(alpha+1), -alpha, newDepth + doDeeperSearch, !cutNode); + // 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 > (alpha + 66 + 11 * (newDepth - d)); + const bool doEvenDeeperSearch = value > alpha + 582 && ss->doubleExtensions <= 5; + const bool doShallowerSearch = value < bestValue + newDepth; + + ss->doubleExtensions = ss->doubleExtensions + doEvenDeeperSearch; + + newDepth += doDeeperSearch - doShallowerSearch + doEvenDeeperSearch; + + if (newDepth > d) + value = -search(pos, ss+1, -(alpha+1), -alpha, newDepth, !cutNode); int bonus = value > alpha ? stat_bonus(newDepth) : -stat_bonus(newDepth); @@ -1201,10 +1209,10 @@ moves_loop: // When in check, search starts here } } - // Step 18. Full depth search when LMR is skipped + // Step 18. Full depth search when LMR is skipped. If expected reduction is high, reduce its depth by 1. else if (!PvNode || moveCount > 1) { - value = -search(pos, ss+1, -(alpha+1), -alpha, newDepth, !cutNode); + value = -search(pos, ss+1, -(alpha+1), -alpha, newDepth - (r > 4), !cutNode); } // For PV nodes only, do a full PV search on the first move or after a fail @@ -1241,8 +1249,18 @@ moves_loop: // When in check, search starts here // PV move or new best move? if (moveCount == 1 || value > alpha) { - rm.score = value; + rm.score = rm.uciScore = value; rm.selDepth = thisThread->selDepth; + rm.scoreLowerbound = rm.scoreUpperbound = false; + + if (value >= beta) { + rm.scoreLowerbound = true; + rm.uciScore = beta; + } + else if (value <= alpha) { + rm.scoreUpperbound = true; + rm.uciScore = alpha; + } rm.pv.resize(1); assert((ss+1)->pv); @@ -1280,11 +1298,11 @@ moves_loop: // When in check, search starts here alpha = value; // Reduce other moves if we have found at least one score improvement - if ( depth > 2 - && depth < 7 + if ( depth > 1 + && depth < 6 && beta < VALUE_KNOWN_WIN && alpha > -VALUE_KNOWN_WIN) - depth -= 1; + depth -= 1; assert(depth > 0); } @@ -1296,8 +1314,6 @@ moves_loop: // When in check, search starts here } } } - else - ss->cutoffCnt = 0; // If the move is worse than some previously searched move, remember it to update its stats later @@ -1337,16 +1353,17 @@ moves_loop: // When in check, search starts here quietsSearched, quietCount, capturesSearched, captureCount, depth); // Bonus for prior countermove that caused the fail low - else if ( (depth >= 5 || PvNode) + else if ( (depth >= 5 || PvNode || bestValue < alpha - 65 * depth) && !priorCapture) { //Assign extra bonus if current node is PvNode or cutNode //or fail low was really bad bool extraBonus = PvNode - || cutNode - || bestValue < alpha - 66 * depth; + || cutNode; + + bool doubleExtraBonus = extraBonus && bestValue < alpha - 88 * depth; - update_continuation_histories(ss-1, pos.piece_on(prevSq), prevSq, stat_bonus(depth) * (1 + extraBonus)); + update_continuation_histories(ss-1, pos.piece_on(prevSq), prevSq, stat_bonus(depth) * (1 + extraBonus + doubleExtraBonus)); } if (PvNode) @@ -1446,7 +1463,7 @@ moves_loop: // When in check, search starts here if ((ss->staticEval = bestValue = tte->eval()) == VALUE_NONE) ss->staticEval = bestValue = evaluate(pos); - // ttValue can be used as a better position evaluation (~7 Elo) + // ttValue can be used as a better position evaluation (~13 Elo) if ( ttValue != VALUE_NONE && (tte->bound() & (ttValue > bestValue ? BOUND_LOWER : BOUND_UPPER))) bestValue = ttValue; @@ -1471,7 +1488,7 @@ moves_loop: // When in check, search starts here if (PvNode && bestValue > alpha) alpha = bestValue; - futilityBase = bestValue + 118; + futilityBase = bestValue + 158; } const PieceToHistory* contHist[] = { (ss-1)->continuationHistory, (ss-2)->continuationHistory, @@ -1504,14 +1521,13 @@ moves_loop: // When in check, search starts here moveCount++; - // Futility pruning and moveCount pruning (~5 Elo) + // Futility pruning and moveCount pruning (~10 Elo) if ( bestValue > VALUE_TB_LOSS_IN_MAX_PLY && !givesCheck && to_sq(move) != prevSq && futilityBase > -VALUE_KNOWN_WIN && type_of(move) != PROMOTION) { - if (moveCount > 2) continue; @@ -1544,19 +1560,18 @@ moves_loop: // When in check, search starts here [pos.moved_piece(move)] [to_sq(move)]; - // Continuation history based pruning (~2 Elo) + // Continuation history based pruning (~3 Elo) if ( !capture && bestValue > VALUE_TB_LOSS_IN_MAX_PLY - && (*contHist[0])[pos.moved_piece(move)][to_sq(move)] < CounterMovePruneThreshold - && (*contHist[1])[pos.moved_piece(move)][to_sq(move)] < CounterMovePruneThreshold) + && (*contHist[0])[pos.moved_piece(move)][to_sq(move)] < 0 + && (*contHist[1])[pos.moved_piece(move)][to_sq(move)] < 0) continue; - // movecount pruning for quiet check evasions + // We prune after 2nd quiet check evasion where being 'in check' is implicitly checked through the counter + // and being a 'quiet' apart from being a tt move is assumed after an increment because captures are pushed ahead. if ( bestValue > VALUE_TB_LOSS_IN_MAX_PLY - && quietCheckEvasions > 1 - && !capture - && ss->inCheck) - continue; + && quietCheckEvasions > 1) + break; quietCheckEvasions += !capture && ss->inCheck; @@ -1675,8 +1690,8 @@ moves_loop: // When in check, search starts here if (!pos.capture(bestMove)) { - int bonus2 = bestValue > beta + PawnValueMg ? bonus1 // larger bonus - : stat_bonus(depth); // smaller bonus + int bonus2 = bestValue > beta + 146 ? bonus1 // larger bonus + : stat_bonus(depth); // smaller bonus // Increase stats for the best move in case it was a quiet move update_quiet_stats(pos, ss, bestMove, bonus2); @@ -1820,7 +1835,7 @@ void MainThread::check_time() { /// UCI::pv() formats PV information according to the UCI protocol. UCI requires /// that all (if any) unsearched PV lines are sent using a previous search score. -string UCI::pv(const Position& pos, Depth depth, Value alpha, Value beta) { +string UCI::pv(const Position& pos, Depth depth) { std::stringstream ss; TimePoint elapsed = Time.elapsed() + 1; @@ -1838,7 +1853,7 @@ string UCI::pv(const Position& pos, Depth depth, Value alpha, Value beta) { continue; Depth d = updated ? depth : std::max(1, depth - 1); - Value v = updated ? rootMoves[i].score : rootMoves[i].previousScore; + Value v = updated ? rootMoves[i].uciScore : rootMoves[i].previousScore; if (v == -VALUE_INFINITE) v = VALUE_ZERO; @@ -1858,16 +1873,13 @@ string UCI::pv(const Position& pos, Depth depth, Value alpha, Value beta) { if (Options["UCI_ShowWDL"]) ss << UCI::wdl(v, pos.game_ply()); - if (!tb && i == pvIdx) - ss << (v >= beta ? " lowerbound" : v <= alpha ? " upperbound" : ""); + if (i == pvIdx && !tb && updated) // tablebase- and previous-scores are exact + ss << (rootMoves[i].scoreLowerbound ? " lowerbound" : (rootMoves[i].scoreUpperbound ? " upperbound" : "")); ss << " nodes " << nodesSearched - << " nps " << nodesSearched * 1000 / elapsed; - - if (elapsed > 1000) // Earlier makes little sense - ss << " hashfull " << TT.hashfull(); - - ss << " tbhits " << tbHits + << " nps " << nodesSearched * 1000 / elapsed + << " hashfull " << TT.hashfull() + << " tbhits " << tbHits << " time " << elapsed << " pv";