X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=ab34a8451cceda529f7996faf4df0500d6715f0c;hp=13affe1b2f06e0a30fd95b5ea5548aad61c3c524;hb=58452de86d120ca7894917c656ecbb56a6273f22;hpb=f0b0a3b1358e5ae4b20ec973634288cfc802828b diff --git a/src/search.cpp b/src/search.cpp index 13affe1b..ab34a845 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -172,10 +172,16 @@ namespace { const bool PruneDefendingMoves = false; const bool PruneBlockingMoves = false; + // Only move margin + const Value OnlyMoveMargin = Value(100); + // Margins for futility pruning in the quiescence search, and at frontier // and near frontier nodes. const Value FutilityMarginQS = Value(0x80); + // Each move futility margin is decreased + const Value IncrementalFutilityMargin = Value(0x8); + // Remaining depth: 1 ply 1.5 ply 2 ply 2.5 ply 3 ply 3.5 ply const Value FutilityMargins[12] = { Value(0x100), Value(0x120), Value(0x200), Value(0x220), Value(0x250), Value(0x270), // 4 ply 4.5 ply 5 ply 5.5 ply 6 ply 6.5 ply @@ -274,7 +280,7 @@ namespace { Value id_loop(const Position& pos, Move searchMoves[]); Value root_search(Position& pos, SearchStack ss[], RootMoveList& rml, Value alpha, Value beta); Value search_pv(Position& pos, SearchStack ss[], Value alpha, Value beta, Depth depth, int ply, int threadID); - Value search(Position& pos, SearchStack ss[], Value beta, Depth depth, int ply, bool allowNullmove, int threadID); + Value search(Position& pos, SearchStack ss[], Value beta, Depth depth, int ply, bool allowNullmove, int threadID, Move forbiddenMove = MOVE_NONE); Value qsearch(Position& pos, SearchStack ss[], Value alpha, Value beta, Depth depth, int ply, int threadID); void sp_search(SplitPoint* sp, int threadID); void sp_search_pv(SplitPoint* sp, int threadID); @@ -288,7 +294,6 @@ namespace { bool ok_to_do_nullmove(const Position& pos); bool ok_to_prune(const Position& pos, Move m, Move threat, Depth d); bool ok_to_use_TT(const TTEntry* tte, Depth depth, Value beta, int ply); - bool ok_to_history(const Position& pos, Move m); void update_history(const Position& pos, Move m, Depth depth, Move movesSearched[], int moveCount); void update_killers(Move m, SearchStack& ss); @@ -311,7 +316,7 @@ namespace { Value *alpha, Value *beta, Value *bestValue, const Value futilityValue, const Value approximateValue, Depth depth, int *moves, - MovePicker *mp, Bitboard dcCandidates, int master, bool pvNode); + MovePicker *mp, int master, bool pvNode); void wake_sleeping_threads(); #if !defined(_MSC_VER) @@ -327,6 +332,37 @@ namespace { //// Functions //// + +/// perft() is our utility to verify move generation is bug free. All the +/// legal moves up to given depth are generated and counted and the sum returned. + +int perft(Position& pos, Depth depth) +{ + Move move; + int sum = 0; + MovePicker mp = MovePicker(pos, MOVE_NONE, depth, H); + + // If we are at the last ply we don't need to do and undo + // the moves, just to count them. + if (depth <= OnePly) // Replace with '<' to test also qsearch + { + while (mp.get_next_move()) sum++; + return sum; + } + + // Loop through all legal moves + CheckInfo ci(pos); + while ((move = mp.get_next_move()) != MOVE_NONE) + { + StateInfo st; + pos.do_move(move, st, ci, pos.move_is_check(move, ci)); + sum += perft(pos, depth - OnePly); + pos.undo_move(move); + } + return sum; +} + + /// think() is the external interface to Stockfish's search, and is called when /// the program receives the UCI 'go' command. It initializes various /// search-related global variables, and calls root_search(). It returns false @@ -448,7 +484,7 @@ bool think(const Position& pos, bool infinite, bool ponder, int side_to_move, if (movesToGo == 1) { MaxSearchTime = myTime / 2; - AbsoluteMaxSearchTime = + AbsoluteMaxSearchTime = (myTime > 3000)? (myTime - 500) : ((myTime * 3) / 4); } else { MaxSearchTime = myTime / Min(movesToGo, 20); @@ -832,7 +868,7 @@ namespace { Value oldAlpha = alpha; Value value; - Bitboard dcCandidates = pos.discovered_check_candidates(pos.side_to_move()); + CheckInfo ci(pos); // Loop through all the moves in the root move list for (int i = 0; i < rml.move_count() && !AbortSearch; i++) @@ -868,13 +904,14 @@ namespace { << " currmovenumber " << i + 1 << std::endl; // Decide search depth for this move - bool moveIsCapture = pos.move_is_capture(move); + bool moveIsCheck = pos.move_is_check(move); + bool captureOrPromotion = pos.move_is_capture_or_promotion(move); bool dangerous; - ext = extension(pos, move, true, moveIsCapture, pos.move_is_check(move), false, false, &dangerous); + ext = extension(pos, move, true, captureOrPromotion, moveIsCheck, false, false, &dangerous); newDepth = (Iteration - 2) * OnePly + ext + InitialDepth; // Make the move, and search it - pos.do_move(move, st, dcCandidates); + pos.do_move(move, st, ci, moveIsCheck); if (i < MultiPV) { @@ -897,8 +934,7 @@ namespace { if ( newDepth >= 3*OnePly && i >= MultiPV + LMRPVMoves && !dangerous - && !moveIsCapture - && !move_is_promotion(move) + && !captureOrPromotion && !move_is_castle(move)) { ss[0].reduction = OnePly; @@ -978,7 +1014,7 @@ namespace { std::cout << std::endl; if (UseLogFile) - LogFile << pretty_pv(pos, current_search_time(), Iteration, nodes_searched(), value, + LogFile << pretty_pv(pos, current_search_time(), Iteration, nodes_searched(), value, ((value >= beta)? VALUE_TYPE_LOWER : ((value <= alpha)? VALUE_TYPE_UPPER : VALUE_TYPE_EXACT)), ss[0].pv) @@ -1033,6 +1069,17 @@ namespace { assert(ply >= 0 && ply < PLY_MAX); assert(threadID >= 0 && threadID < ActiveThreads); + Move movesSearched[256]; + EvalInfo ei; + StateInfo st; + const TTEntry* tte; + Move ttMove, move; + Depth ext, newDepth; + Value oldAlpha, value; + bool isCheck, mateThreat, singleReply, moveIsCheck, captureOrPromotion, dangerous; + int moveCount = 0; + Value bestValue = -VALUE_INFINITE; + if (depth < OnePly) return qsearch(pos, ss, alpha, beta, Depth(0), ply, threadID); @@ -1047,13 +1094,11 @@ namespace { if (pos.is_draw()) return VALUE_DRAW; - EvalInfo ei; - if (ply >= PLY_MAX - 1) return pos.is_check() ? quick_evaluate(pos) : evaluate(pos, ei, threadID); // Mate distance pruning - Value oldAlpha = alpha; + oldAlpha = alpha; alpha = Max(value_mated_in(ply), alpha); beta = Min(value_mate_in(ply+1), beta); if (alpha >= beta) @@ -1061,8 +1106,8 @@ namespace { // Transposition table lookup. At PV nodes, we don't use the TT for // pruning, but only for move ordering. - const TTEntry* tte = TT.retrieve(pos.get_key()); - Move ttMove = (tte ? tte->move() : MOVE_NONE); + tte = TT.retrieve(pos.get_key()); + ttMove = (tte ? tte->move() : MOVE_NONE); // Go with internal iterative deepening if we don't have a TT move if (UseIIDAtPVNodes && ttMove == MOVE_NONE && depth >= 5*OnePly) @@ -1073,15 +1118,10 @@ namespace { // Initialize a MovePicker object for the current position, and prepare // to search all moves - Move move, movesSearched[256]; - int moveCount = 0; - Value value, bestValue = -VALUE_INFINITE; - Color us = pos.side_to_move(); - bool isCheck = pos.is_check(); - bool mateThreat = pos.has_mate_threat(opposite_color(us)); - + isCheck = pos.is_check(); + mateThreat = pos.has_mate_threat(opposite_color(pos.side_to_move())); + CheckInfo ci(pos); MovePicker mp = MovePicker(pos, ttMove, depth, H, &ss[ply]); - Bitboard dcCandidates = mp.discovered_check_candidates(); // Loop through all legal moves until no moves remain or a beta cutoff // occurs. @@ -1091,20 +1131,40 @@ namespace { { assert(move_is_ok(move)); - bool singleReply = (isCheck && mp.number_of_evasions() == 1); - bool moveIsCheck = pos.move_is_check(move, dcCandidates); - bool moveIsCapture = pos.move_is_capture(move); + singleReply = (isCheck && mp.number_of_evasions() == 1); + moveIsCheck = pos.move_is_check(move, ci); + captureOrPromotion = pos.move_is_capture_or_promotion(move); - movesSearched[moveCount++] = ss[ply].currentMove = move; + movesSearched[moveCount++] = move; // Decide the new search depth - bool dangerous; - Depth ext = extension(pos, move, true, moveIsCapture, moveIsCheck, singleReply, mateThreat, &dangerous); - Depth newDepth = depth - OnePly + ext; + ext = extension(pos, move, true, captureOrPromotion, moveIsCheck, singleReply, mateThreat, &dangerous); + + // Only move extension + if ( moveCount == 1 + && ext < OnePly + && depth >= 4 * OnePly + && tte + && (tte->type() & VALUE_TYPE_LOWER) + && tte->move() != MOVE_NONE + && tte->depth() >= depth - 3 * OnePly) + { + Value ttValue = value_from_tt(tte->value(), ply); + if (abs(ttValue) < VALUE_KNOWN_WIN) + { + Value excValue = search(pos, ss, ttValue - OnlyMoveMargin, Max(Min(depth / 2, depth - 4 * OnePly), OnePly), ply, false, threadID, tte->move()); + if (excValue < ttValue - OnlyMoveMargin) + ext = (depth >= 8 * OnePly)? OnePly : ext + OnePly / 2; + } + } + + newDepth = depth - OnePly + ext; + + // Update current move + ss[ply].currentMove = move; // Make and search the move - StateInfo st; - pos.do_move(move, st, dcCandidates); + pos.do_move(move, st, ci, moveIsCheck); if (moveCount == 1) // The first move in list is the PV value = -search_pv(pos, ss, -beta, -alpha, newDepth, ply+1, threadID); @@ -1115,8 +1175,7 @@ namespace { if ( depth >= 3*OnePly && moveCount >= LMRPVMoves && !dangerous - && !moveIsCapture - && !move_is_promotion(move) + && !captureOrPromotion && !move_is_castle(move) && !move_is_killer(move, ss[ply])) { @@ -1178,8 +1237,8 @@ namespace { && idle_thread_exists(threadID) && !AbortSearch && !thread_should_stop(threadID) - && split(pos, ss, ply, &alpha, &beta, &bestValue, VALUE_NONE, VALUE_NONE, depth, - &moveCount, &mp, dcCandidates, threadID, true)) + && split(pos, ss, ply, &alpha, &beta, &bestValue, VALUE_NONE, VALUE_NONE, + depth, &moveCount, &mp, threadID, true)) break; } @@ -1199,13 +1258,13 @@ namespace { else if (bestValue >= beta) { BetaCounter.add(pos.side_to_move(), depth, threadID); - Move m = ss[ply].pv[ply]; - if (ok_to_history(pos, m)) // Only non capture moves are considered + move = ss[ply].pv[ply]; + if (!pos.move_is_capture_or_promotion(move)) { - update_history(pos, m, depth, movesSearched, moveCount); - update_killers(m, ss[ply]); + update_history(pos, move, depth, movesSearched, moveCount); + update_killers(move, ss[ply]); } - TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, depth, m); + TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, depth, move); } else TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_EXACT, depth, ss[ply].pv[ply]); @@ -1217,12 +1276,24 @@ namespace { // search() is the search function for zero-width nodes. Value search(Position& pos, SearchStack ss[], Value beta, Depth depth, - int ply, bool allowNullmove, int threadID) { + int ply, bool allowNullmove, int threadID, Move forbiddenMove) { assert(beta >= -VALUE_INFINITE && beta <= VALUE_INFINITE); assert(ply >= 0 && ply < PLY_MAX); assert(threadID >= 0 && threadID < ActiveThreads); + Move movesSearched[256]; + EvalInfo ei; + StateInfo st; + const TTEntry* tte; + Move ttMove, move; + Depth ext, newDepth; + Value approximateEval, nullValue, value, futilityValue, futilityValueScaled; + bool isCheck, useFutilityPruning, singleReply, moveIsCheck, captureOrPromotion, dangerous; + bool mateThreat = false; + int moveCount = 0; + Value bestValue = -VALUE_INFINITE; + if (depth < OnePly) return qsearch(pos, ss, beta-1, beta, Depth(0), ply, threadID); @@ -1237,8 +1308,6 @@ namespace { if (pos.is_draw()) return VALUE_DRAW; - EvalInfo ei; - if (ply >= PLY_MAX - 1) return pos.is_check() ? quick_evaluate(pos) : evaluate(pos, ei, threadID); @@ -1249,9 +1318,15 @@ namespace { if (value_mate_in(ply + 1) < beta) return beta - 1; + // Position key calculation + Key posKey = pos.get_key(); + + if (forbiddenMove != MOVE_NONE) + posKey ^= Position::zobExclusion; + // Transposition table lookup - const TTEntry* tte = TT.retrieve(pos.get_key()); - Move ttMove = (tte ? tte->move() : MOVE_NONE); + tte = TT.retrieve(posKey); + ttMove = (tte ? tte->move() : MOVE_NONE); if (tte && ok_to_use_TT(tte, depth, beta, ply)) { @@ -1259,9 +1334,8 @@ namespace { return value_from_tt(tte->value(), ply); } - Value approximateEval = quick_evaluate(pos); - bool mateThreat = false; - bool isCheck = pos.is_check(); + approximateEval = quick_evaluate(pos); + isCheck = pos.is_check(); // Null move search if ( allowNullmove @@ -1273,11 +1347,16 @@ namespace { { ss[ply].currentMove = MOVE_NULL; - StateInfo st; pos.do_null_move(st); - int R = (depth >= 5 * OnePly ? 4 : 3); // Null move dynamic reduction - Value nullValue = -search(pos, ss, -(beta-1), depth-R*OnePly, ply+1, false, threadID); + // Null move dynamic reduction based on depth + int R = (depth >= 5 * OnePly ? 4 : 3); + + // Null move dynamic reduction based on value + if (approximateEval - beta > PawnValueMidgame) + R++; + + nullValue = -search(pos, ss, -(beta-1), depth-R*OnePly, ply+1, false, threadID); pos.undo_null_move(); @@ -1315,8 +1394,9 @@ namespace { && ttMove == MOVE_NONE && !pos.has_pawn_on_7th(pos.side_to_move())) { - Value v = qsearch(pos, ss, beta-1, beta, Depth(0), ply, threadID); - if (v < beta - RazorMargins[int(depth) - 2]) + Value rbeta = beta - RazorMargins[int(depth) - 2]; + Value v = qsearch(pos, ss, rbeta-1, rbeta, Depth(0), ply, threadID); + if (v < rbeta) return v; } @@ -1331,19 +1411,17 @@ namespace { // Initialize a MovePicker object for the current position, and prepare // to search all moves. MovePicker mp = MovePicker(pos, ttMove, depth, H, &ss[ply]); - - Move move, movesSearched[256]; - int moveCount = 0; - Value value, bestValue = -VALUE_INFINITE; - Bitboard dcCandidates = mp.discovered_check_candidates(); - Value futilityValue = VALUE_NONE; - bool useFutilityPruning = depth < SelectiveDepth - && !isCheck; + CheckInfo ci(pos); + futilityValue = VALUE_NONE; + useFutilityPruning = depth < SelectiveDepth && !isCheck; // Avoid calling evaluate() if we already have the score in TT if (tte && (tte->type() & VALUE_TYPE_EVAL)) futilityValue = value_from_tt(tte->value(), ply) + FutilityMargins[int(depth) - 2]; + // Move count pruning limit + const int MCLimit = 3 + (1 << (3*int(depth)/8)); + // Loop through all legal moves until no moves remain or a beta cutoff // occurs. while ( bestValue < beta @@ -1352,25 +1430,97 @@ namespace { { assert(move_is_ok(move)); - bool singleReply = (isCheck && mp.number_of_evasions() == 1); - bool moveIsCheck = pos.move_is_check(move, dcCandidates); - bool moveIsCapture = pos.move_is_capture(move); + if (move == forbiddenMove) + continue; + + singleReply = (isCheck && mp.number_of_evasions() == 1); + moveIsCheck = pos.move_is_check(move, ci); + captureOrPromotion = pos.move_is_capture_or_promotion(move); - movesSearched[moveCount++] = ss[ply].currentMove = move; + movesSearched[moveCount++] = move; // Decide the new search depth - bool dangerous; - Depth ext = extension(pos, move, false, moveIsCapture, moveIsCheck, singleReply, mateThreat, &dangerous); - Depth newDepth = depth - OnePly + ext; + ext = extension(pos, move, false, captureOrPromotion, moveIsCheck, singleReply, mateThreat, &dangerous); + + // Only move extension + if ( forbiddenMove == MOVE_NONE + && moveCount == 1 + && ext < OnePly + && depth >= 4 * OnePly + && tte + && (tte->type() & VALUE_TYPE_LOWER) + && tte->move() != MOVE_NONE + && tte->depth() >= depth - 3 * OnePly) + { + Value ttValue = value_from_tt(tte->value(), ply); + if (abs(ttValue) < VALUE_KNOWN_WIN) + { + Value excValue = search(pos, ss, ttValue - OnlyMoveMargin, Max(Min(depth / 2, depth - 4 * OnePly), OnePly), ply, false, threadID, tte->move()); + if (excValue < ttValue - OnlyMoveMargin) + ext = (depth >= 8 * OnePly)? OnePly : ext + OnePly / 2; + } + } + + newDepth = depth - OnePly + ext; + + // Update current move + ss[ply].currentMove = move; // Futility pruning if ( useFutilityPruning && !dangerous - && !moveIsCapture - && !move_is_promotion(move)) + && !captureOrPromotion + && move != ttMove) { + //std::cout << std::endl; + //for (int d = 2; d < 14; d++) + // std::cout << d << ", " << 64*(1+bitScanReverse32(d*d)) << std::endl; + + //std::cout << std::endl; +/* + 64*(1+bitScanReverse32(d*d)) + + 2 -> 256 - 256 + 3 -> 288 - 320 + 4 -> 512 - 384 + 5 -> 544 - 384 + 6 -> 592 - 448 + 7 -> 624 - 448 + 8 -> 672 - 512 + 9 -> 704 - 512 + 10 -> 832 - 512 + 11 -> 864 - 512 + 12 -> 928 - 576 + 13 -> 960 - 576 + + 300 + 2*(1 << (3*d/4)) + + 2 -> 256 - 304 + 3 -> 288 - 308 + 4 -> 512 - 316 + 5 -> 544 - 316 + 6 -> 592 - 332 + 7 -> 624 - 364 + 8 -> 672 - 428 + 9 -> 704 - 428 + 10 -> 832 - 556 + 11 -> 864 - 812 + 12 -> 928 - 1324 + 13 -> 960 - 1324 + + + 3 + (1 << (3*int(depth)/8)) + + 1 * onePly - > moveCount >= 4 + 2 * onePly - > moveCount >= 5 + 3 * onePly - > moveCount >= 7 + 4 * onePly - > moveCount >= 11 + 5 * onePly - > moveCount >= 11 + 6 * onePly - > moveCount >= 19 + 7 * onePly - > moveCount >= 35 +*/ // History pruning. See ok_to_prune() definition - if ( moveCount >= 2 + int(depth) + if ( moveCount >= MCLimit && ok_to_prune(pos, move, ss[ply].threatMove, depth) && bestValue > value_mated_in(PLY_MAX)) continue; @@ -1380,28 +1530,28 @@ namespace { { if (futilityValue == VALUE_NONE) futilityValue = evaluate(pos, ei, threadID) - + FutilityMargins[int(depth) - 2]; + + 64*(2+bitScanReverse32(int(depth) * int(depth))); - if (futilityValue < beta) + futilityValueScaled = futilityValue - moveCount * IncrementalFutilityMargin; + + if (futilityValueScaled < beta) { - if (futilityValue > bestValue) - bestValue = futilityValue; + if (futilityValueScaled > bestValue) + bestValue = futilityValueScaled; continue; } } } // Make and search the move - StateInfo st; - pos.do_move(move, st, dcCandidates); + pos.do_move(move, st, ci, moveIsCheck); // Try to reduce non-pv search depth by one ply if move seems not problematic, // if the move fails high will be re-searched at full depth. if ( depth >= 3*OnePly && moveCount >= LMRNonPVMoves && !dangerous - && !moveIsCapture - && !move_is_promotion(move) + && !captureOrPromotion && !move_is_castle(move) && !move_is_killer(move, ss[ply])) { @@ -1439,15 +1589,15 @@ namespace { && idle_thread_exists(threadID) && !AbortSearch && !thread_should_stop(threadID) - && split(pos, ss, ply, &beta, &beta, &bestValue, futilityValue, approximateEval, depth, &moveCount, - &mp, dcCandidates, threadID, false)) + && split(pos, ss, ply, &beta, &beta, &bestValue, futilityValue, approximateEval, + depth, &moveCount, &mp, threadID, false)) break; } // All legal moves have been searched. A special case: If there were // no legal moves, it must be mate or stalemate. if (moveCount == 0) - return (pos.is_check() ? value_mated_in(ply) : VALUE_DRAW); + return (forbiddenMove == MOVE_NONE ? (pos.is_check() ? value_mated_in(ply) : VALUE_DRAW) : beta - 1); // If the search is not aborted, update the transposition table, // history counters, and killer moves. @@ -1455,17 +1605,17 @@ namespace { return bestValue; if (bestValue < beta) - TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_UPPER, depth, MOVE_NONE); + TT.store(posKey, value_to_tt(bestValue, ply), VALUE_TYPE_UPPER, depth, MOVE_NONE); else { BetaCounter.add(pos.side_to_move(), depth, threadID); - Move m = ss[ply].pv[ply]; - if (ok_to_history(pos, m)) // Only non capture moves are considered + move = ss[ply].pv[ply]; + if (!pos.move_is_capture_or_promotion(move)) { - update_history(pos, m, depth, movesSearched, moveCount); - update_killers(m, ss[ply]); + update_history(pos, move, depth, movesSearched, moveCount); + update_killers(move, ss[ply]); } - TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, depth, m); + TT.store(posKey, value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, depth, move); } assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE); @@ -1487,6 +1637,15 @@ namespace { assert(ply >= 0 && ply < PLY_MAX); assert(threadID >= 0 && threadID < ActiveThreads); + EvalInfo ei; + StateInfo st; + Move ttMove, move; + Value staticValue, bestValue, value, futilityValue; + bool isCheck, enoughMaterial, moveIsCheck; + const TTEntry* tte = NULL; + int moveCount = 0; + bool pvNode = (beta - alpha != 1); + // Initialize, and make an early exit in case of an aborted search, // an instant draw, maximum ply reached, etc. init_node(ss, ply, threadID); @@ -1499,8 +1658,6 @@ namespace { return VALUE_DRAW; // Transposition table lookup, only when not in PV - TTEntry* tte = NULL; - bool pvNode = (beta - alpha != 1); if (!pvNode) { tte = TT.retrieve(pos.get_key()); @@ -1511,12 +1668,10 @@ namespace { return value_from_tt(tte->value(), ply); } } - Move ttMove = (tte ? tte->move() : MOVE_NONE); + ttMove = (tte ? tte->move() : MOVE_NONE); // Evaluate the position statically - EvalInfo ei; - Value staticValue; - bool isCheck = pos.is_check(); + isCheck = pos.is_check(); ei.futilityMargin = Value(0); // Manually initialize futilityMargin if (isCheck) @@ -1537,7 +1692,7 @@ namespace { // Initialize "stand pat score", and return it immediately if it is // at least beta. - Value bestValue = staticValue; + bestValue = staticValue; if (bestValue >= beta) { @@ -1555,11 +1710,8 @@ namespace { // to search the moves. Because the depth is <= 0 here, only captures, // queen promotions and checks (only if depth == 0) will be generated. MovePicker mp = MovePicker(pos, ttMove, depth, H); - Move move; - int moveCount = 0; - Bitboard dcCandidates = mp.discovered_check_candidates(); - Color us = pos.side_to_move(); - bool enoughMaterial = pos.non_pawn_material(us) > RookValueMidgame; + CheckInfo ci(pos); + enoughMaterial = pos.non_pawn_material(pos.side_to_move()) > RookValueMidgame; // Loop through the moves until no moves remain or a beta cutoff // occurs. @@ -1571,20 +1723,23 @@ namespace { moveCount++; ss[ply].currentMove = move; + moveIsCheck = pos.move_is_check(move, ci); + // Futility pruning if ( enoughMaterial && !isCheck && !pvNode + && !moveIsCheck + && move != ttMove && !move_is_promotion(move) - && !pos.move_is_check(move, dcCandidates) && !pos.move_is_passed_pawn_push(move)) { - Value futilityValue = staticValue - + Max(pos.midgame_value_of_piece_on(move_to(move)), - pos.endgame_value_of_piece_on(move_to(move))) - + (move_is_ep(move) ? PawnValueEndgame : Value(0)) - + FutilityMarginQS - + ei.futilityMargin; + futilityValue = staticValue + + Max(pos.midgame_value_of_piece_on(move_to(move)), + pos.endgame_value_of_piece_on(move_to(move))) + + (move_is_ep(move) ? PawnValueEndgame : Value(0)) + + FutilityMarginQS + + ei.futilityMargin; if (futilityValue < alpha) { @@ -1596,14 +1751,14 @@ namespace { // Don't search captures and checks with negative SEE values if ( !isCheck + && move != ttMove && !move_is_promotion(move) && pos.see_sign(move) < 0) continue; - // Make and search the move. - StateInfo st; - pos.do_move(move, st, dcCandidates); - Value value = -qsearch(pos, ss, -beta, -alpha, depth-OnePly, ply+1, threadID); + // Make and search the move + pos.do_move(move, st, ci, moveIsCheck); + value = -qsearch(pos, ss, -beta, -alpha, depth-OnePly, ply+1, threadID); pos.undo_move(move); assert(value > -VALUE_INFINITE && value < VALUE_INFINITE); @@ -1622,13 +1777,13 @@ namespace { // All legal moves have been searched. A special case: If we're in check // and no legal moves were found, it is checkmate. - if (pos.is_check() && moveCount == 0) // Mate! + if (!moveCount && pos.is_check()) // Mate! return value_mated_in(ply); assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE); // Update transposition table - Move m = ss[ply].pv[ply]; + move = ss[ply].pv[ply]; if (!pvNode) { // If bestValue isn't changed it means it is still the static evaluation of @@ -1639,12 +1794,12 @@ namespace { if (bestValue < beta) TT.store(pos.get_key(), value_to_tt(bestValue, ply), type, d, MOVE_NONE); else - TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, d, m); + TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, d, move); } // Update killers only for good check moves - if (alpha >= beta && ok_to_history(pos, m)) // Only non capture moves are considered - update_killers(m, ss[ply]); + if (alpha >= beta && !pos.move_is_capture_or_promotion(move)) + update_killers(move, ss[ply]); return bestValue; } @@ -1664,6 +1819,7 @@ namespace { assert(ActiveThreads > 1); Position pos = Position(sp->pos); + CheckInfo ci(pos); SearchStack* ss = sp->sstack[threadID]; Value value; Move move; @@ -1677,8 +1833,8 @@ namespace { { assert(move_is_ok(move)); - bool moveIsCheck = pos.move_is_check(move, sp->dcCandidates); - bool moveIsCapture = pos.move_is_capture(move); + bool moveIsCheck = pos.move_is_check(move, ci); + bool captureOrPromotion = pos.move_is_capture_or_promotion(move); lock_grab(&(sp->lock)); int moveCount = ++sp->moves; @@ -1688,14 +1844,13 @@ namespace { // Decide the new search depth. bool dangerous; - Depth ext = extension(pos, move, false, moveIsCapture, moveIsCheck, false, false, &dangerous); + Depth ext = extension(pos, move, false, captureOrPromotion, moveIsCheck, false, false, &dangerous); Depth newDepth = sp->depth - OnePly + ext; // Prune? if ( useFutilityPruning && !dangerous - && !moveIsCapture - && !move_is_promotion(move)) + && !captureOrPromotion) { // History pruning. See ok_to_prune() definition if ( moveCount >= 2 + int(sp->depth) @@ -1729,14 +1884,13 @@ namespace { // Make and search the move. StateInfo st; - pos.do_move(move, st, sp->dcCandidates); + pos.do_move(move, st, ci, moveIsCheck); // Try to reduce non-pv search depth by one ply if move seems not problematic, // if the move fails high will be re-searched at full depth. if ( !dangerous && moveCount >= LMRNonPVMoves - && !moveIsCapture - && !move_is_promotion(move) + && !captureOrPromotion && !move_is_castle(move) && !move_is_killer(move, ss[sp->ply])) { @@ -1759,21 +1913,24 @@ namespace { break; // New best move? - lock_grab(&(sp->lock)); - if (value > sp->bestValue && !thread_should_stop(threadID)) + if (value > sp->bestValue) // Less then 2% of cases { - sp->bestValue = value; - if (sp->bestValue >= sp->beta) + lock_grab(&(sp->lock)); + if (value > sp->bestValue && !thread_should_stop(threadID)) { - sp_update_pv(sp->parentSstack, ss, sp->ply); - for (int i = 0; i < ActiveThreads; i++) - if (i != threadID && (i == sp->master || sp->slaves[i])) - Threads[i].stop = true; + sp->bestValue = value; + if (sp->bestValue >= sp->beta) + { + sp_update_pv(sp->parentSstack, ss, sp->ply); + for (int i = 0; i < ActiveThreads; i++) + if (i != threadID && (i == sp->master || sp->slaves[i])) + Threads[i].stop = true; - sp->finished = true; - } + sp->finished = true; + } + } + lock_release(&(sp->lock)); } - lock_release(&(sp->lock)); } lock_grab(&(sp->lock)); @@ -1806,6 +1963,7 @@ namespace { assert(ActiveThreads > 1); Position pos = Position(sp->pos); + CheckInfo ci(pos); SearchStack* ss = sp->sstack[threadID]; Value value; Move move; @@ -1814,8 +1972,8 @@ namespace { && !thread_should_stop(threadID) && (move = sp->mp->get_next_move(sp->lock)) != MOVE_NONE) { - bool moveIsCheck = pos.move_is_check(move, sp->dcCandidates); - bool moveIsCapture = pos.move_is_capture(move); + bool moveIsCheck = pos.move_is_check(move, ci); + bool captureOrPromotion = pos.move_is_capture_or_promotion(move); assert(move_is_ok(move)); @@ -1827,19 +1985,18 @@ namespace { // Decide the new search depth. bool dangerous; - Depth ext = extension(pos, move, true, moveIsCapture, moveIsCheck, false, false, &dangerous); + Depth ext = extension(pos, move, true, captureOrPromotion, moveIsCheck, false, false, &dangerous); Depth newDepth = sp->depth - OnePly + ext; // Make and search the move. StateInfo st; - pos.do_move(move, st, sp->dcCandidates); + pos.do_move(move, st, ci, moveIsCheck); // Try to reduce non-pv search depth by one ply if move seems not problematic, // if the move fails high will be re-searched at full depth. if ( !dangerous && moveCount >= LMRPVMoves - && !moveIsCapture - && !move_is_promotion(move) + && !captureOrPromotion && !move_is_castle(move) && !move_is_killer(move, ss[sp->ply])) { @@ -2264,8 +2421,8 @@ namespace { // extended, as example because the corresponding UCI option is set to zero, // the move is marked as 'dangerous' so, at least, we avoid to prune it. - Depth extension(const Position& pos, Move m, bool pvNode, bool capture, bool check, - bool singleReply, bool mateThreat, bool* dangerous) { + Depth extension(const Position& pos, Move m, bool pvNode, bool captureOrPromotion, + bool check, bool singleReply, bool mateThreat, bool* dangerous) { assert(m != MOVE_NONE); @@ -2299,7 +2456,7 @@ namespace { } } - if ( capture + if ( captureOrPromotion && pos.type_of_piece_on(move_to(m)) != PAWN && ( pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK) - pos.midgame_value_of_piece_on(move_to(m)) == Value(0)) @@ -2311,7 +2468,7 @@ namespace { } if ( pvNode - && capture + && captureOrPromotion && pos.type_of_piece_on(move_to(m)) != PAWN && pos.see_sign(m) >= 0) { @@ -2345,9 +2502,8 @@ namespace { assert(move_is_ok(m)); assert(threat == MOVE_NONE || move_is_ok(threat)); - assert(!move_is_promotion(m)); assert(!pos.move_is_check(m)); - assert(!pos.move_is_capture(m)); + assert(!pos.move_is_capture_or_promotion(m)); assert(!pos.move_is_passed_pawn_push(m)); assert(d >= OnePly); @@ -2409,15 +2565,6 @@ namespace { } - // ok_to_history() returns true if a move m can be stored - // in history. Should be a non capturing move nor a promotion. - - bool ok_to_history(const Position& pos, Move m) { - - return !pos.move_is_capture(m) && !move_is_promotion(m); - } - - // update_history() registers a good move that produced a beta-cutoff // in history and marks as failures all the other moves of that ply. @@ -2429,7 +2576,7 @@ namespace { for (int i = 0; i < moveCount - 1; i++) { assert(m != movesSearched[i]); - if (ok_to_history(pos, movesSearched[i])) + if (!pos.move_is_capture_or_promotion(movesSearched[i])) H.failure(pos.piece_on(move_from(movesSearched[i])), move_to(movesSearched[i])); } } @@ -2787,7 +2934,7 @@ namespace { bool split(const Position& p, SearchStack* sstck, int ply, Value* alpha, Value* beta, Value* bestValue, const Value futilityValue, const Value approximateEval, Depth depth, int* moves, - MovePicker* mp, Bitboard dcCandidates, int master, bool pvNode) { + MovePicker* mp, int master, bool pvNode) { assert(p.is_ok()); assert(sstck != NULL); @@ -2824,7 +2971,6 @@ namespace { splitPoint->alpha = pvNode? *alpha : (*beta - 1); splitPoint->beta = *beta; splitPoint->pvNode = pvNode; - splitPoint->dcCandidates = dcCandidates; splitPoint->bestValue = *bestValue; splitPoint->futilityValue = futilityValue; splitPoint->approximateEval = approximateEval;