X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Fsearch.cpp;h=4a41a8b0b09e275284424c37bed3d8f2edcb69d3;hb=5372f81cc81d5be3040db6f2dbfff108c460baf9;hp=426f7937220936592a530fe88ca030ce55ad1cec;hpb=08ac4e9db5d763edb788f3b01ea5c3bac494defa;p=stockfish diff --git a/src/search.cpp b/src/search.cpp index 426f7937..4a41a8b0 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -63,7 +63,7 @@ namespace { // Futility margin Value futility_margin(Depth d, bool improving) { - return Value(214 * (d - improving)); + return Value(168 * (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 + 1358 - int(delta) * 1024 / int(rootDelta)) / 1024 + (!i && r > 904); + return (r + 1463 - int(delta) * 1024 / int(rootDelta)) / 1024 + (!i && r > 1010); } constexpr int futility_move_count(bool improving, Depth depth) { @@ -80,7 +80,7 @@ namespace { // History and stats update bonus, based on depth int stat_bonus(Depth d) { - return std::min((6 * d + 229) * d - 215 , 2000); + return std::min((9 * d + 270) * d - 311 , 2145); } // Add a small random component to draw evaluations to avoid 3-fold blindness @@ -157,7 +157,7 @@ namespace { void Search::init() { for (int i = 1; i < MAX_MOVES; ++i) - Reductions[i] = int((21.9 + std::log(Threads.size()) / 2) * std::log(i)); + Reductions[i] = int((20.81 + std::log(Threads.size()) / 2) * std::log(i)); } @@ -238,6 +238,9 @@ void MainThread::search() { bestPreviousScore = bestThread->rootMoves[0].score; bestPreviousAverageScore = bestThread->rootMoves[0].averageScore; + for (Thread* th : Threads) + th->previousDepth = bestThread->completedDepth; + // 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; @@ -303,10 +306,10 @@ void Thread::search() { multiPV = std::min(multiPV, rootMoves.size()); - complexityAverage.set(232, 1); + complexityAverage.set(202, 1); trend = SCORE_ZERO; - optimism[ us] = Value(25); + optimism[ us] = Value(39); optimism[~us] = -optimism[us]; int searchAgainCounter = 0; @@ -349,16 +352,16 @@ void Thread::search() { if (rootDepth >= 4) { Value prev = rootMoves[pvIdx].averageScore; - delta = Value(17) + int(prev) * prev / 16384; + delta = Value(16) + int(prev) * prev / 19178; 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, 0, 0, 147, 113, 1); + 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, 0, 25, 147, 14464, 256); + int opt = sigmoid(prev, 8, 17, 144, 13966, 183); optimism[ us] = Value(opt); optimism[~us] = -optimism[us]; } @@ -413,7 +416,7 @@ void Thread::search() { else break; - delta += delta / 4 + 5; + delta += delta / 4 + 2; assert(alpha >= -VALUE_INFINITE && beta <= VALUE_INFINITE); } @@ -459,17 +462,16 @@ void Thread::search() { && !Threads.stop && !mainThread->stopOnPonderhit) { - double fallingEval = (142 + 12 * (mainThread->bestPreviousAverageScore - bestValue) - + 6 * (mainThread->iterValue[iterIdx] - bestValue)) / 825.0; + double fallingEval = (69 + 12 * (mainThread->bestPreviousAverageScore - bestValue) + + 6 * (mainThread->iterValue[iterIdx] - bestValue)) / 781.4; fallingEval = std::clamp(fallingEval, 0.5, 1.5); // If the bestMove is stable over several iterations, reduce time accordingly - timeReduction = lastBestMoveDepth + 9 < completedDepth ? 1.92 : 0.95; - double reduction = (1.47 + mainThread->previousTimeReduction) / (2.32 * timeReduction); - double bestMoveInstability = 1.073 + std::max(1.0, 2.25 - 9.9 / rootDepth) - * totBestMoveChanges / Threads.size(); + timeReduction = lastBestMoveDepth + 10 < completedDepth ? 1.63 : 0.73; + double reduction = (1.56 + mainThread->previousTimeReduction) / (2.20 * timeReduction); + double bestMoveInstability = 1 + 1.7 * totBestMoveChanges / Threads.size(); int complexity = mainThread->complexityAverage.value(); - double complexPosition = std::clamp(1.0 + (complexity - 232) / 1750.0, 0.5, 1.5); + double complexPosition = std::clamp(1.0 + (complexity - 326) / 1618.1, 0.5, 1.5); double totalTime = Time.optimum() * fallingEval * reduction * bestMoveInstability * complexPosition; @@ -490,7 +492,7 @@ void Thread::search() { } else if ( Threads.increaseDepth && !mainThread->ponder - && Time.elapsed() > totalTime * 0.58) + && Time.elapsed() > totalTime * 0.43) Threads.increaseDepth = false; else Threads.increaseDepth = true; @@ -554,16 +556,17 @@ namespace { Depth extension, newDepth; Value bestValue, value, ttValue, eval, maxValue, probCutBeta; bool givesCheck, improving, didLMR, priorCapture; - bool captureOrPromotion, doFullDepthSearch, moveCountPruning, ttCapture; + bool capture, doFullDepthSearch, moveCountPruning, ttCapture; Piece movedPiece; - int moveCount, captureCount, quietCount, bestMoveCount, improvement, complexity; + int moveCount, captureCount, quietCount, improvement, complexity; // Step 1. Initialize node Thread* thisThread = pos.this_thread(); + thisThread->depth = depth; ss->inCheck = pos.checkers(); priorCapture = pos.captured_piece(); Color us = pos.side_to_move(); - moveCount = bestMoveCount = captureCount = quietCount = ss->moveCount = 0; + moveCount = captureCount = quietCount = ss->moveCount = 0; bestValue = -VALUE_INFINITE; maxValue = VALUE_INFINITE; @@ -603,6 +606,7 @@ namespace { (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; ss->depth = depth; Square prevSq = to_sq((ss-1)->currentMove); @@ -624,7 +628,7 @@ namespace { ttValue = ss->ttHit ? value_from_tt(tte->value(), ss->ply, pos.rule50_count()) : VALUE_NONE; ttMove = rootNode ? thisThread->rootMoves[thisThread->pvIdx].pv[0] : ss->ttHit ? tte->move() : MOVE_NONE; - ttCapture = ttMove && pos.capture_or_promotion(ttMove); + ttCapture = ttMove && pos.capture(ttMove); if (!excludedMove) ss->ttPv = PvNode || (ss->ttHit && tte->is_pv()); @@ -766,7 +770,7 @@ 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 - : 200; + : 175; improving = improvement > 0; complexity = abs(ss->staticEval - (us == WHITE ? eg_value(pos.psq_score()) : -eg_value(pos.psq_score()))); @@ -777,8 +781,8 @@ namespace { // If eval is really low check with qsearch if it can exceed alpha, if it can't, // return a fail low. if ( !PvNode - && depth <= 6 - && eval < alpha - 400 - 300 * depth * depth) + && depth <= 7 + && eval < alpha - 348 - 258 * depth * depth) { value = qsearch(pos, ss, alpha - 1, alpha); if (value < alpha) @@ -788,19 +792,19 @@ namespace { // Step 8. Futility pruning: child node (~25 Elo). // The depth condition is important for mate finding. if ( !ss->ttPv - && depth < 9 + && depth < 8 && eval - futility_margin(depth, improving) - (ss-1)->statScore / 256 >= beta && eval >= beta - && eval < 15000) // 50% larger than VALUE_KNOWN_WIN, but smaller than TB wins. + && eval < 26305) // larger than VALUE_KNOWN_WIN, but smaller than TB wins. return eval; // Step 9. Null move search with verification search (~22 Elo) if ( !PvNode && (ss-1)->currentMove != MOVE_NULL - && (ss-1)->statScore < 23767 + && (ss-1)->statScore < 14695 && eval >= beta && eval >= ss->staticEval - && ss->staticEval >= beta - 20 * depth - improvement / 15 + 204 + complexity / 25 + && ss->staticEval >= beta - 15 * depth - improvement / 15 + 198 + complexity / 28 && !excludedMove && pos.non_pawn_material(us) && (ss->ply >= thisThread->nmpMinPly || us != thisThread->nmpColor)) @@ -808,7 +812,7 @@ namespace { assert(eval - beta >= 0); // Null move dynamic reduction based on depth, eval and complexity of position - Depth R = std::min(int(eval - beta) / 205, 3) + depth / 3 + 4 - (complexity > 500); + Depth R = std::min(int(eval - beta) / 147, 5) + depth / 3 + 4 - (complexity > 753); ss->currentMove = MOVE_NULL; ss->continuationHistory = &thisThread->continuationHistory[0][0][NO_PIECE][0]; @@ -844,7 +848,7 @@ namespace { } } - probCutBeta = beta + 209 - 44 * improving; + probCutBeta = beta + 179 - 46 * improving; // Step 10. ProbCut (~4 Elo) // If we have a good enough capture and a reduced search returns a value @@ -863,15 +867,15 @@ namespace { { assert(probCutBeta < VALUE_INFINITE); - MovePicker mp(pos, ttMove, probCutBeta - ss->staticEval, &captureHistory); + MovePicker mp(pos, ttMove, probCutBeta - ss->staticEval, depth - 3, &captureHistory); bool ttPv = ss->ttPv; + bool captureOrPromotion; ss->ttPv = false; while ((move = mp.next_move()) != MOVE_NONE) if (move != excludedMove && pos.legal(move)) { - assert(pos.capture_or_promotion(move)); - assert(depth >= 5); + assert(pos.capture(move) || promotion_type(move) == QUEEN); captureOrPromotion = true; @@ -909,22 +913,22 @@ namespace { // Step 11. If the position is not in TT, decrease depth by 2 or 1 depending on node type (~3 Elo) if ( PvNode - && depth >= 6 + && depth >= 3 && !ttMove) depth -= 2; if ( cutNode - && depth >= 9 + && depth >= 8 && !ttMove) depth--; moves_loop: // When in check, search starts here // Step 12. A small Probcut idea, when we are in check (~0 Elo) - probCutBeta = beta + 409; + probCutBeta = beta + 481; if ( ss->inCheck && !PvNode - && depth >= 4 + && depth >= 2 && ttCapture && (tte->bound() & BOUND_LOWER) && tte->depth() >= depth - 3 @@ -988,7 +992,7 @@ moves_loop: // When in check, search starts here (ss+1)->pv = nullptr; extension = 0; - captureOrPromotion = pos.capture_or_promotion(move); + capture = pos.capture(move); movedPiece = pos.moved_piece(move); givesCheck = pos.gives_check(move); @@ -1008,7 +1012,7 @@ moves_loop: // When in check, search starts here // Reduced depth of the next LMR search int lmrDepth = std::max(newDepth - reduction(improving, depth, moveCount, delta, thisThread->rootDelta), 0); - if ( captureOrPromotion + if ( capture || givesCheck) { // Futility pruning for captures (~0 Elo) @@ -1017,12 +1021,12 @@ moves_loop: // When in check, search starts here && !PvNode && lmrDepth < 6 && !ss->inCheck - && ss->staticEval + 342 + 238 * lmrDepth + PieceValue[EG][pos.piece_on(to_sq(move))] - + captureHistory[movedPiece][to_sq(move)][type_of(pos.piece_on(to_sq(move)))] / 8 < alpha) + && ss->staticEval + 281 + 179 * 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(-217) * depth)) + if (!pos.see_ge(move, Value(-203) * depth)) continue; } else @@ -1040,12 +1044,12 @@ moves_loop: // When in check, search starts here // Futility pruning: parent node (~9 Elo) if ( !ss->inCheck - && lmrDepth < 8 - && ss->staticEval + 138 + 137 * lmrDepth + history / 64 <= alpha) + && lmrDepth < 11 + && ss->staticEval + 122 + 138 * lmrDepth + history / 60 <= alpha) continue; // Prune moves with negative SEE (~3 Elo) - if (!pos.see_ge(move, Value(-21 * lmrDepth * lmrDepth - 21 * lmrDepth))) + if (!pos.see_ge(move, Value(-25 * lmrDepth * lmrDepth - 20 * lmrDepth))) continue; } } @@ -1060,7 +1064,7 @@ 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 >= 6 + 2 * (PvNode && tte->is_pv()) + && depth >= 4 - (thisThread->previousDepth > 27) + 2 * (PvNode && tte->is_pv()) && move == ttMove && !excludedMove // Avoid recursive singular search /* && ttValue != VALUE_NONE Already implicit in the next condition */ @@ -1081,8 +1085,8 @@ moves_loop: // When in check, search starts here // Avoid search explosion by limiting the number of double extensions if ( !PvNode - && value < singularBeta - 75 - && ss->doubleExtensions <= 6) + && value < singularBeta - 26 + && ss->doubleExtensions <= 8) extension = 2; } @@ -1097,19 +1101,23 @@ moves_loop: // When in check, search starts here // If the eval of ttMove is greater than beta, we reduce it (negative extension) else if (ttValue >= beta) extension = -2; + + // If the eval of ttMove is less than alpha and value, we reduce it (negative extension) + else if (ttValue <= alpha && ttValue <= value) + extension = -1; } // Check extensions (~1 Elo) else if ( givesCheck - && depth > 6 - && abs(ss->staticEval) > 100) + && depth > 9 + && abs(ss->staticEval) > 71) extension = 1; // Quiet ttMove extensions (~0 Elo) else if ( PvNode && move == ttMove && move == ss->killers[0] - && (*contHist[0])[movedPiece][to_sq(move)] >= 10000) + && (*contHist[0])[movedPiece][to_sq(move)] >= 5491) extension = 1; } @@ -1123,7 +1131,7 @@ moves_loop: // When in check, search starts here // Update the current move (this must be done after singular extension search) ss->currentMove = move; ss->continuationHistory = &thisThread->continuationHistory[ss->inCheck] - [captureOrPromotion] + [capture] [movedPiece] [to_sq(move)]; @@ -1136,19 +1144,14 @@ moves_loop: // When in check, search starts here // 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 >= 3 - && moveCount > 1 + 2 * rootNode + if ( depth >= 2 + && moveCount > 1 + (PvNode && ss->ply <= 1) && ( !ss->ttPv - || !captureOrPromotion + || !capture || (cutNode && (ss-1)->moveCount > 1))) { Depth r = reduction(improving, depth, moveCount, delta, thisThread->rootDelta); - // Decrease reduction at some PvNodes (~2 Elo) - if ( PvNode - && bestMoveCount <= 3) - r--; - // Decrease reduction if position is or has been on the PV // and node is not likely to fail low. (~3 Elo) if ( ss->ttPv @@ -1156,7 +1159,7 @@ moves_loop: // When in check, search starts here r -= 2; // Decrease reduction if opponent's move count is high (~1 Elo) - if ((ss-1)->moveCount > 13) + if ((ss-1)->moveCount > 7) r--; // Increase reduction for cut nodes (~3 Elo) @@ -1167,22 +1170,35 @@ moves_loop: // When in check, search starts here if (ttCapture) r++; + // Decrease reduction at PvNodes if bestvalue + // is vastly different from static evaluation + if (PvNode && !ss->inCheck && abs(ss->staticEval - bestValue) > 250) + r--; + + // Decrease reduction for PvNodes based on depth + if (PvNode) + r -= 1 + 15 / ( 3 + depth ); + + // Increase reduction if next ply has a lot of fail high else reset count to 0 + if ((ss+1)->cutoffCnt > 3 && !PvNode) + r++; + 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)] - - 4923; + - 4334; // Decrease/increase reduction for moves with a good/bad history (~30 Elo) - r -= ss->statScore / 14721; + r -= ss->statScore / 15914; // In general we want to cap the LMR depth search at newDepth. But if reductions // are really negative and movecount is low, we allow this move to be searched // deeper than the first move (this may lead to hidden double extensions). int deeper = r >= -1 ? 0 - : moveCount <= 5 ? 2 - : PvNode && depth > 6 ? 1 - : cutNode && moveCount <= 7 ? 1 + : moveCount <= 4 ? 2 + : PvNode && depth > 4 ? 1 + : cutNode && moveCount <= 8 ? 1 : 0; Depth d = std::clamp(newDepth - r, 1, newDepth + deeper); @@ -1191,7 +1207,7 @@ moves_loop: // When in check, search starts here // If the son is reduced and fails high it will be re-searched at full depth doFullDepthSearch = value > alpha && d < newDepth; - doDeeperSearch = value > (alpha + 62 + 20 * (newDepth - d)); + doDeeperSearch = value > (alpha + 78 + 11 * (newDepth - d)); didLMR = true; } else @@ -1211,8 +1227,8 @@ moves_loop: // When in check, search starts here int bonus = value > alpha ? stat_bonus(newDepth) : -stat_bonus(newDepth); - if (captureOrPromotion) - bonus /= 4; + if (capture) + bonus /= 6; update_continuation_histories(ss, movedPiece, to_sq(move), bonus); } @@ -1289,23 +1305,35 @@ moves_loop: // When in check, search starts here if (PvNode && value < beta) // Update alpha! Always alpha < beta { alpha = value; - bestMoveCount++; + + // Reduce other moves if we have found at least one score improvement + if ( depth > 2 + && depth < 7 + && beta < VALUE_KNOWN_WIN + && alpha > -VALUE_KNOWN_WIN) + depth -= 1; + + assert(depth > 0); } else { + ss->cutoffCnt++; assert(value >= beta); // Fail high break; } } } + else + ss->cutoffCnt = 0; + // If the move is worse than some previously searched move, remember it to update its stats later if (move != bestMove) { - if (captureOrPromotion && captureCount < 32) + if (capture && captureCount < 32) capturesSearched[captureCount++] = move; - else if (!captureOrPromotion && quietCount < 64) + else if (!capture && quietCount < 64) quietsSearched[quietCount++] = move; } } @@ -1336,14 +1364,14 @@ 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 >= 3 || PvNode) + else if ( (depth >= 4 || PvNode) && !priorCapture) { //Assign extra bonus if current node is PvNode or cutNode //or fail low was really bad bool extraBonus = PvNode || cutNode - || bestValue < alpha - 94 * depth; + || bestValue < alpha - 70 * depth; update_continuation_histories(ss-1, pos.piece_on(prevSq), prevSq, stat_bonus(depth) * (1 + extraBonus)); } @@ -1355,10 +1383,6 @@ moves_loop: // When in check, search starts here // opponent move is probably good and the new position is added to the search tree. if (bestValue <= alpha) ss->ttPv = ss->ttPv || ((ss-1)->ttPv && depth > 3); - // Otherwise, a counter move has been found and if the position is the last leaf - // in the search tree, remove the position from the search tree. - else if (depth > 3) - ss->ttPv = ss->ttPv && (ss+1)->ttPv; // Write gathered information in transposition table if (!excludedMove && !(rootNode && thisThread->pvIdx)) @@ -1394,7 +1418,7 @@ moves_loop: // When in check, search starts here Move ttMove, move, bestMove; Depth ttDepth; Value bestValue, value, ttValue, futilityValue, futilityBase; - bool pvHit, givesCheck, captureOrPromotion; + bool pvHit, givesCheck, capture; int moveCount; if (PvNode) @@ -1474,7 +1498,7 @@ moves_loop: // When in check, search starts here if (PvNode && bestValue > alpha) alpha = bestValue; - futilityBase = bestValue + 155; + futilityBase = bestValue + 118; } const PieceToHistory* contHist[] = { (ss-1)->continuationHistory, (ss-2)->continuationHistory, @@ -1503,7 +1527,7 @@ moves_loop: // When in check, search starts here continue; givesCheck = pos.gives_check(move); - captureOrPromotion = pos.capture_or_promotion(move); + capture = pos.capture(move); moveCount++; @@ -1543,12 +1567,12 @@ moves_loop: // When in check, search starts here ss->currentMove = move; ss->continuationHistory = &thisThread->continuationHistory[ss->inCheck] - [captureOrPromotion] + [capture] [pos.moved_piece(move)] [to_sq(move)]; // Continuation history based pruning (~2 Elo) - if ( !captureOrPromotion + 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) @@ -1557,11 +1581,11 @@ moves_loop: // When in check, search starts here // movecount pruning for quiet check evasions if ( bestValue > VALUE_TB_LOSS_IN_MAX_PLY && quietCheckEvasions > 1 - && !captureOrPromotion + && !capture && ss->inCheck) continue; - quietCheckEvasions += !captureOrPromotion && ss->inCheck; + quietCheckEvasions += !capture && ss->inCheck; // Make and search the move pos.do_move(move, st, givesCheck); @@ -1680,7 +1704,7 @@ moves_loop: // When in check, search starts here bonus2 = bestValue > beta + PawnValueMg ? bonus1 // larger bonus : stat_bonus(depth); // smaller bonus - if (!pos.capture_or_promotion(bestMove)) + if (!pos.capture(bestMove)) { // Increase stats for the best move in case it was a quiet move update_quiet_stats(pos, ss, bestMove, bonus2);