X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=037c44ddfe37a483a373c34c8b9eed1f3246c4e5;hp=25a3984d69331cb8a927e4424c6d0734e8440f29;hb=bb3427ca85bdb20b4c8af12b63f635d03c5e9146;hpb=08abe8b4a33ab409f5b61ebcb9216ddf8a605e95 diff --git a/src/search.cpp b/src/search.cpp index 25a3984d..037c44dd 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -24,6 +24,7 @@ #include #include #include +#include #include "book.h" #include "evaluate.h" @@ -41,6 +42,16 @@ using std::cout; using std::endl; using std::string; +using Search::Signals; +using Search::Limits; + +namespace Search { + + volatile SignalsType Signals; + LimitsType Limits; + std::vector RootMoves; + Position RootPosition; +} namespace { @@ -73,7 +84,7 @@ namespace { // RootMoveList struct is mainly a std::vector of RootMove objects struct RootMoveList : public std::vector { - void init(Position& pos, Move searchMoves[]); + void init(Position& pos, Move rootMoves[]); RootMove* find(const Move& m, int startIndex = 0); int bestMoveChanges; @@ -128,7 +139,7 @@ namespace { inline Value futility_margin(Depth d, int mn) { - return d < 7 * ONE_PLY ? FutilityMargins[Max(d, 1)][Min(mn, 63)] + return d < 7 * ONE_PLY ? FutilityMargins[std::max(int(d), 1)][std::min(mn, 63)] : 2 * VALUE_INFINITE; } @@ -144,12 +155,12 @@ namespace { template inline Depth reduction(Depth d, int mn) { - return (Depth) Reductions[PvNode][Min(d / ONE_PLY, 63)][Min(mn, 63)]; + return (Depth) Reductions[PvNode][std::min(int(d) / ONE_PLY, 63)][std::min(mn, 63)]; } // Easy move margin. An easy move candidate must be at least this much // better than the second best move. - const Value EasyMoveMargin = Value(0x200); + const Value EasyMoveMargin = Value(0x150); /// Namespace variables @@ -161,26 +172,19 @@ namespace { int MultiPV, UCIMultiPV, MultiPVIdx; // Time management variables - bool StopOnPonderhit, FirstRootMove, StopRequest, QuitRequest, AspirationFailLow; TimeManager TimeMgr; - SearchLimits Limits; // Skill level adjustment int SkillLevel; bool SkillLevelEnabled; - // Node counters, used only by thread[0] but try to keep in different cache - // lines (64 bytes each) from the heavy multi-thread read accessed variables. - int NodesSincePoll; - int NodesBetweenPolls = 30000; - // History table History H; /// Local functions - Move id_loop(Position& pos, Move searchMoves[], Move* ponderMove); + Move id_loop(Position& pos, Move rootMoves[], Move* ponderMove); template Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth); @@ -196,17 +200,14 @@ namespace { bool connected_threat(const Position& pos, Move m, Move threat); Value refine_eval(const TTEntry* tte, Value defaultEval, int ply); void update_history(const Position& pos, Move move, Depth depth, Move movesSearched[], int moveCount); - void update_gains(const Position& pos, Move move, Value before, Value after); void do_skill_level(Move* best, Move* ponder); - int current_search_time(int set = 0); + int elapsed_search_time(int set = 0); string score_to_uci(Value v, Value alpha = -VALUE_INFINITE, Value beta = VALUE_INFINITE); string speed_to_uci(int64_t nodes); string pv_to_uci(const Move pv[], int pvNum, bool chess960); string pretty_pv(Position& pos, int depth, Value score, int time, Move pv[]); string depth_to_uci(Depth depth); - void poll(const Position& pos); - void wait_for_stop_or_ponderhit(); // MovePickerExt template class extends MovePicker and allows to choose at compile // time the proper moves source according to the type of node. In the default case @@ -291,7 +292,7 @@ namespace { *dangerous = true; } - return Min(result, ONE_PLY); + return std::min(result, ONE_PLY); } } // namespace @@ -299,7 +300,7 @@ namespace { /// init_search() is called during startup to initialize various lookup tables -void init_search() { +void Search::init() { int d; // depth (ONE_PLY == 2) int hd; // half depth (ONE_PLY == 1) @@ -327,7 +328,7 @@ void init_search() { /// perft() is our utility to verify move generation. All the leaf nodes up to /// the given depth are generated and counted and the sum returned. -int64_t perft(Position& pos, Depth depth) { +int64_t Search::perft(Position& pos, Depth depth) { StateInfo st; int64_t sum = 0; @@ -357,29 +358,17 @@ int64_t perft(Position& pos, Depth depth) { /// variables, and calls id_loop(). It returns false when a "quit" command is /// received during the search. -bool think(Position& pos, const SearchLimits& limits, Move searchMoves[]) { +void Search::think() { - static Book book; // Define static to initialize the PRNG only once + static Book book; // Defined static to initialize the PRNG only once - // Initialize global search-related variables - StopOnPonderhit = StopRequest = QuitRequest = AspirationFailLow = false; - NodesSincePoll = 0; - current_search_time(get_system_time()); - Limits = limits; - TimeMgr.init(Limits, pos.startpos_ply_counter()); + Position& pos = RootPosition; - // Set output steram in normal or chess960 mode - cout << set960(pos.is_chess960()); + // Save "search start" time and reset elapsed time to zero + elapsed_search_time(get_system_time()); - // Set best NodesBetweenPolls interval to avoid lagging under time pressure - if (Limits.maxNodes) - NodesBetweenPolls = Min(Limits.maxNodes, 30000); - else if (Limits.time && Limits.time < 1000) - NodesBetweenPolls = 1000; - else if (Limits.time && Limits.time < 5000) - NodesBetweenPolls = 5000; - else - NodesBetweenPolls = 30000; + // Set output stream mode: normal or chess960. Castling notation is different + cout << set960(pos.is_chess960()); // Look for a book move if (Options["OwnBook"].value()) @@ -390,18 +379,15 @@ bool think(Position& pos, const SearchLimits& limits, Move searchMoves[]) { Move bookMove = book.probe(pos, Options["Best Book Move"].value()); if (bookMove != MOVE_NONE) { - if (Limits.ponder) - wait_for_stop_or_ponderhit(); + if (!Signals.stop && (Limits.ponder || Limits.infinite)) + Threads.wait_for_stop_or_ponderhit(); cout << "bestmove " << bookMove << endl; - return !QuitRequest; + return; } } - // Read UCI options - UCIMultiPV = Options["MultiPV"].value(); - SkillLevel = Options["Skill Level"].value(); - + // Read UCI options: GUI could change UCI parameters during the game read_evaluation_uci_options(pos.side_to_move()); Threads.read_uci_options(); @@ -414,19 +400,15 @@ bool think(Position& pos, const SearchLimits& limits, Move searchMoves[]) { TT.clear(); } + UCIMultiPV = Options["MultiPV"].value(); + SkillLevel = Options["Skill Level"].value(); + // Do we have to play with skill handicap? In this case enable MultiPV that // we will use behind the scenes to retrieve a set of possible moves. SkillLevelEnabled = (SkillLevel < 20); - MultiPV = (SkillLevelEnabled ? Max(UCIMultiPV, 4) : UCIMultiPV); - - // Wake up needed threads and reset maxPly counter - for (int i = 0; i < Threads.size(); i++) - { - Threads[i].wake_up(); - Threads[i].maxPly = 0; - } + MultiPV = (SkillLevelEnabled ? std::max(UCIMultiPV, 4) : UCIMultiPV); - // Write to log file and keep it open to be accessed during the search + // Write current search header to log file if (Options["Use Search Log"].value()) { Log log(Options["Search Log Filename"].value()); @@ -439,18 +421,40 @@ bool think(Position& pos, const SearchLimits& limits, Move searchMoves[]) { << endl; } + // Wake up needed threads and reset maxPly counter + for (int i = 0; i < Threads.size(); i++) + { + Threads[i].maxPly = 0; + Threads[i].wake_up(); + } + + // Set best timer interval to avoid lagging under time pressure. Timer is + // used to check for remaining available thinking time. + TimeMgr.init(Limits, pos.startpos_ply_counter()); + + if (TimeMgr.available_time()) + Threads.set_timer(std::min(100, std::max(TimeMgr.available_time() / 8, 20))); + else + Threads.set_timer(100); + // We're ready to start thinking. Call the iterative deepening loop function Move ponderMove = MOVE_NONE; - Move bestMove = id_loop(pos, searchMoves, &ponderMove); + Move bestMove = id_loop(pos, &RootMoves[0], &ponderMove); + + // Stop timer, no need to check for available time any more + Threads.set_timer(0); - // Write final search statistics and close log file + // This makes all the slave threads to go to sleep, if not already sleeping + Threads.set_size(1); + + // Write current search final statistics to log file if (Options["Use Search Log"].value()) { - int t = current_search_time(); + int e = elapsed_search_time(); Log log(Options["Search Log Filename"].value()); log << "Nodes: " << pos.nodes_searched() - << "\nNodes/second: " << (t > 0 ? pos.nodes_searched() * 1000 / t : 0) + << "\nNodes/second: " << (e > 0 ? pos.nodes_searched() * 1000 / e : 0) << "\nBest move: " << move_to_san(pos, bestMove); StateInfo st; @@ -459,13 +463,11 @@ bool think(Position& pos, const SearchLimits& limits, Move searchMoves[]) { pos.undo_move(bestMove); // Return from think() with unchanged position } - // This makes all the threads to go to sleep - Threads.set_size(1); - - // If we are pondering or in infinite search, we shouldn't print the - // best move before we are told to do so. - if (!StopRequest && (Limits.ponder || Limits.infinite)) - wait_for_stop_or_ponderhit(); + // When we reach max depth we arrive here even without a StopRequest, but if + // we are pondering or in infinite search, we shouldn't print the best move + // before we are told to do so. + if (!Signals.stop && (Limits.ponder || Limits.infinite)) + Threads.wait_for_stop_or_ponderhit(); // Could be MOVE_NONE when searching on a stalemate position cout << "bestmove " << bestMove; @@ -476,8 +478,6 @@ bool think(Position& pos, const SearchLimits& limits, Move searchMoves[]) { cout << " ponder " << ponderMove; cout << endl; - - return !QuitRequest; } @@ -487,26 +487,27 @@ namespace { // with increasing depth until the allocated thinking time has been consumed, // user stops the search, or the maximum search depth is reached. - Move id_loop(Position& pos, Move searchMoves[], Move* ponderMove) { + Move id_loop(Position& pos, Move rootMoves[], Move* ponderMove) { SearchStack ss[PLY_MAX_PLUS_2]; Value bestValues[PLY_MAX_PLUS_2]; int bestMoveChanges[PLY_MAX_PLUS_2]; int depth, aspirationDelta; - Value value, alpha, beta; - Move bestMove, easyMove, skillBest, skillPonder; + Value bestValue, alpha, beta; + Move bestMove, skillBest, skillPonder; + bool bestMoveNeverChanged = true; // Initialize stuff before a new search memset(ss, 0, 4 * sizeof(SearchStack)); TT.new_search(); H.clear(); - *ponderMove = bestMove = easyMove = skillBest = skillPonder = MOVE_NONE; + *ponderMove = bestMove = skillBest = skillPonder = MOVE_NONE; depth = aspirationDelta = 0; - value = alpha = -VALUE_INFINITE, beta = VALUE_INFINITE; - ss->currentMove = MOVE_NULL; // Hack to skip update_gains() + bestValue = alpha = -VALUE_INFINITE, beta = VALUE_INFINITE; + ss->currentMove = MOVE_NULL; // Hack to skip update gains // Moves to search are verified and copied - Rml.init(pos, searchMoves); + Rml.init(pos, rootMoves); // Handle special case of searching on a mate/stalemate position if (!Rml.size()) @@ -518,7 +519,7 @@ namespace { } // Iterative deepening loop until requested to stop or target depth reached - while (!StopRequest && ++depth <= PLY_MAX && (!Limits.maxDepth || depth <= Limits.maxDepth)) + while (!Signals.stop && ++depth <= PLY_MAX && (!Limits.maxDepth || depth <= Limits.maxDepth)) { // Save now last iteration's scores, before Rml moves are reordered for (size_t i = 0; i < Rml.size(); i++) @@ -527,7 +528,7 @@ namespace { Rml.bestMoveChanges = 0; // MultiPV loop. We perform a full root search for each PV line - for (MultiPVIdx = 0; MultiPVIdx < Min(MultiPV, (int)Rml.size()); MultiPVIdx++) + for (MultiPVIdx = 0; MultiPVIdx < std::min(MultiPV, (int)Rml.size()); MultiPVIdx++) { // Calculate dynamic aspiration window based on previous iterations if (depth >= 5 && abs(Rml[MultiPVIdx].prevScore) < VALUE_KNOWN_WIN) @@ -535,11 +536,11 @@ namespace { int prevDelta1 = bestValues[depth - 1] - bestValues[depth - 2]; int prevDelta2 = bestValues[depth - 2] - bestValues[depth - 3]; - aspirationDelta = Min(Max(abs(prevDelta1) + abs(prevDelta2) / 2, 16), 24); + aspirationDelta = std::min(std::max(abs(prevDelta1) + abs(prevDelta2) / 2, 16), 24); aspirationDelta = (aspirationDelta + 7) / 8 * 8; // Round to match grainSize - alpha = Max(Rml[MultiPVIdx].prevScore - aspirationDelta, -VALUE_INFINITE); - beta = Min(Rml[MultiPVIdx].prevScore + aspirationDelta, VALUE_INFINITE); + alpha = std::max(Rml[MultiPVIdx].prevScore - aspirationDelta, -VALUE_INFINITE); + beta = std::min(Rml[MultiPVIdx].prevScore + aspirationDelta, VALUE_INFINITE); } else { @@ -551,8 +552,8 @@ namespace { // research with bigger window until not failing high/low anymore. do { // Search starts from ss+1 to allow referencing (ss-1). This is - // needed by update_gains() and ss copy when splitting at Root. - value = search(pos, ss+1, alpha, beta, depth * ONE_PLY); + // needed by update gains and ss copy when splitting at Root. + bestValue = search(pos, ss+1, alpha, beta, depth * ONE_PLY); // Bring to front the best move. It is critical that sorting is // done with a stable algorithm because all the values but the first @@ -566,7 +567,7 @@ namespace { // the fail high/low loop then reorder the PV moves, otherwise // leave the last PV move in its position so to be searched again. // Of course this is needed only in MultiPV search. - if (MultiPVIdx && value > alpha && value < beta) + if (MultiPVIdx && bestValue > alpha && bestValue < beta) sort(Rml.begin(), Rml.begin() + MultiPVIdx); // Write PV back to transposition table in case the relevant entries @@ -577,15 +578,15 @@ namespace { // If search has been stopped exit the aspiration window loop, // note that sorting and writing PV back to TT is safe becuase // Rml is still valid, although refers to the previous iteration. - if (StopRequest) + if (Signals.stop) break; // Send full PV info to GUI if we are going to leave the loop or // if we have a fail high/low and we are deep in the search. UCI // protocol requires to send all the PV lines also if are still // to be searched and so refer to the previous search's score. - if ((value > alpha && value < beta) || current_search_time() > 2000) - for (int i = 0; i < Min(UCIMultiPV, (int)Rml.size()); i++) + if ((bestValue > alpha && bestValue < beta) || elapsed_search_time() > 2000) + for (int i = 0; i < std::min(UCIMultiPV, (int)Rml.size()); i++) { bool updated = (i <= MultiPVIdx); @@ -605,29 +606,29 @@ namespace { // In case of failing high/low increase aspiration window and // research, otherwise exit the fail high/low loop. - if (value >= beta) + if (bestValue >= beta) { - beta = Min(beta + aspirationDelta, VALUE_INFINITE); + beta = std::min(beta + aspirationDelta, VALUE_INFINITE); aspirationDelta += aspirationDelta / 2; } - else if (value <= alpha) + else if (bestValue <= alpha) { - AspirationFailLow = true; - StopOnPonderhit = false; + Signals.failedLowAtRoot = true; + Signals.stopOnPonderhit = false; - alpha = Max(alpha - aspirationDelta, -VALUE_INFINITE); + alpha = std::max(alpha - aspirationDelta, -VALUE_INFINITE); aspirationDelta += aspirationDelta / 2; } else break; - } while (abs(value) < VALUE_KNOWN_WIN); + } while (abs(bestValue) < VALUE_KNOWN_WIN); } // Collect info about search result bestMove = Rml[0].pv[0]; *ponderMove = Rml[0].pv[1]; - bestValues[depth] = value; + bestValues[depth] = bestValue; bestMoveChanges[depth] = Rml.bestMoveChanges; // Skills: Do we need to pick now the best and the ponder moves ? @@ -637,29 +638,17 @@ namespace { if (Options["Use Search Log"].value()) { Log log(Options["Search Log Filename"].value()); - log << pretty_pv(pos, depth, value, current_search_time(), &Rml[0].pv[0]) << endl; + log << pretty_pv(pos, depth, bestValue, elapsed_search_time(), &Rml[0].pv[0]) << endl; } - // Init easyMove at first iteration or drop it if differs from the best move - if (depth == 1 && (Rml.size() == 1 || Rml[0].score > Rml[1].score + EasyMoveMargin)) - easyMove = bestMove; - else if (bestMove != easyMove) - easyMove = MOVE_NONE; + // Filter out startup noise when monitoring best move stability + if (depth > 2 && bestMoveChanges[depth]) + bestMoveNeverChanged = false; - // Check for some early stop condition - if (!StopRequest && Limits.useTimeManagement()) + // Do we have time for the next iteration? Can we stop searching now? + if (!Signals.stop && !Signals.stopOnPonderhit && Limits.useTimeManagement()) { - // Easy move: Stop search early if one move seems to be much better - // than the others or if there is only a single legal move. Also in - // the latter case search to some depth anyway to get a proper score. - if ( depth >= 7 - && easyMove == bestMove - && ( Rml.size() == 1 - ||( Rml[0].nodes > (pos.nodes_searched() * 85) / 100 - && current_search_time() > TimeMgr.available_time() / 16) - ||( Rml[0].nodes > (pos.nodes_searched() * 98) / 100 - && current_search_time() > TimeMgr.available_time() / 32))) - StopRequest = true; + bool stop = false; // Local variable instead of the volatile Signals.stop // Take in account some extra time if the best move has changed if (depth > 4 && depth < 50) @@ -667,14 +656,34 @@ namespace { // Stop search if most of available time is already consumed. We probably don't // have enough time to search the first move at the next iteration anyway. - if (current_search_time() > (TimeMgr.available_time() * 62) / 100) - StopRequest = true; + if (elapsed_search_time() > (TimeMgr.available_time() * 62) / 100) + stop = true; + + // Stop search early if one move seems to be much better than others + if ( depth >= 10 + && !stop + && ( bestMoveNeverChanged + || elapsed_search_time() > (TimeMgr.available_time() * 40) / 100)) + { + Value rBeta = bestValue - EasyMoveMargin; + (ss+1)->excludedMove = bestMove; + (ss+1)->skipNullMove = true; + Value v = search(pos, ss+1, rBeta - 1, rBeta, (depth * ONE_PLY) / 2); + (ss+1)->skipNullMove = false; + (ss+1)->excludedMove = MOVE_NONE; + + if (v < rBeta) + stop = true; + } - // If we are allowed to ponder do not stop the search now but keep pondering - if (StopRequest && Limits.ponder) + if (stop) { - StopRequest = false; - StopOnPonderhit = true; + // If we are allowed to ponder do not stop the search now but + // keep pondering until GUI sends "ponderhit" or "stop". + if (Limits.ponder) // FIXME racing + Signals.stopOnPonderhit = true; + else + Signals.stop = true; } } } @@ -722,7 +731,8 @@ namespace { ValueType vt; Value bestValue, value, oldAlpha; Value refinedValue, nullValue, futilityBase, futilityValue; - bool isPvMove, inCheck, singularExtensionNode, givesCheck, captureOrPromotion, dangerous; + bool isPvMove, inCheck, singularExtensionNode, givesCheck; + bool captureOrPromotion, dangerous, doFullDepthSearch; int moveCount = 0, playedMoveCount = 0; Thread& thread = Threads[pos.thread()]; SplitPoint* sp = NULL; @@ -736,7 +746,7 @@ namespace { if (PvNode && thread.maxPly < ss->ply) thread.maxPly = ss->ply; - // Step 1. Initialize node and poll. Polling can abort search + // Step 1. Initialize node if (!SpNode) { ss->currentMove = ss->bestMove = threatMove = (ss+1)->excludedMove = MOVE_NONE; @@ -752,14 +762,8 @@ namespace { goto split_point_start; } - if (pos.thread() == 0 && ++NodesSincePoll > NodesBetweenPolls) - { - NodesSincePoll = 0; - poll(pos); - } - // Step 2. Check for aborted search and immediate draw - if (( StopRequest + if (( Signals.stop || pos.is_draw() || ss->ply > PLY_MAX) && !RootNode) return VALUE_DRAW; @@ -767,8 +771,8 @@ namespace { // Step 3. Mate distance pruning if (!RootNode) { - alpha = Max(value_mated_in(ss->ply), alpha); - beta = Min(value_mate_in(ss->ply+1), beta); + alpha = std::max(value_mated_in(ss->ply), alpha); + beta = std::min(value_mate_in(ss->ply+1), beta); if (alpha >= beta) return alpha; } @@ -820,8 +824,17 @@ namespace { TT.store(posKey, VALUE_NONE, VALUE_TYPE_NONE, DEPTH_NONE, MOVE_NONE, ss->eval, ss->evalMargin); } - // Save gain for the parent non-capture move - update_gains(pos, (ss-1)->currentMove, (ss-1)->eval, ss->eval); + // Update gain for the parent non-capture move given the static position + // evaluation before and after the move. + if ( (move = (ss-1)->currentMove) != MOVE_NULL + && (ss-1)->eval != VALUE_NONE + && ss->eval != VALUE_NONE + && pos.captured_piece_type() == PIECE_TYPE_NONE + && !is_special(move)) + { + Square to = move_to(move); + H.update_gain(pos.piece_on(to), to, -(ss-1)->eval - ss->eval); + } // Step 6. Razoring (is omitted in PV nodes) if ( !PvNode @@ -1009,20 +1022,19 @@ split_point_start: // At split points actual search starts from here if (RootNode) { // This is used by time management - FirstRootMove = (moveCount == 1); + Signals.firstRootMove = (moveCount == 1); // Save the current node count before the move is searched nodes = pos.nodes_searched(); // For long searches send current move info to GUI - if (pos.thread() == 0 && current_search_time() > 2000) + if (pos.thread() == 0 && elapsed_search_time() > 2000) cout << "info" << depth_to_uci(depth) << " currmove " << move << " currmovenumber " << moveCount + MultiPVIdx << endl; } - // At Root and at first iteration do a PV search on all the moves to score root moves - isPvMove = (PvNode && moveCount <= (RootNode && depth <= ONE_PLY ? MAX_MOVES : 1)); + isPvMove = (PvNode && moveCount <= 1); givesCheck = pos.move_gives_check(move, ci); captureOrPromotion = pos.is_capture_or_promotion(move); @@ -1046,11 +1058,11 @@ split_point_start: // At split points actual search starts from here Value rBeta = ttValue - int(depth); ss->excludedMove = move; ss->skipNullMove = true; - Value v = search(pos, ss, rBeta - 1, rBeta, depth / 2); + value = search(pos, ss, rBeta - 1, rBeta, depth / 2); ss->skipNullMove = false; ss->excludedMove = MOVE_NONE; ss->bestMove = MOVE_NONE; - if (v < rBeta) + if (value < rBeta) ext = ONE_PLY; } } @@ -1124,51 +1136,44 @@ split_point_start: // At split points actual search starts from here // Step 14. Make the move pos.do_move(move, st, ci, givesCheck); - // Step extra. pv search (only in PV nodes) - // The first move in list is the expected PV - if (isPvMove) - value = newDepth < ONE_PLY ? -qsearch(pos, ss+1, -beta, -alpha, DEPTH_ZERO) - : - search(pos, ss+1, -beta, -alpha, newDepth); - else + // Step 15. Reduced depth search (LMR). If the move fails high will be + // re-searched at full depth. + if ( depth > 3 * ONE_PLY + && !isPvMove + && !captureOrPromotion + && !dangerous + && !is_castle(move) + && ss->killers[0] != move + && ss->killers[1] != move) { - // Step 15. Reduced depth search - // If the move fails high will be re-searched at full depth. - bool doFullDepthSearch = true; - - if ( depth > 3 * ONE_PLY - && !captureOrPromotion - && !dangerous - && !is_castle(move) - && ss->killers[0] != move - && ss->killers[1] != move - && (ss->reduction = reduction(depth, moveCount)) != DEPTH_ZERO) - { - Depth d = newDepth - ss->reduction; - alpha = SpNode ? sp->alpha : alpha; + ss->reduction = reduction(depth, moveCount); + Depth d = newDepth - ss->reduction; + alpha = SpNode ? sp->alpha : alpha; - value = d < ONE_PLY ? -qsearch(pos, ss+1, -(alpha+1), -alpha, DEPTH_ZERO) - : - search(pos, ss+1, -(alpha+1), -alpha, d); + value = d < ONE_PLY ? -qsearch(pos, ss+1, -(alpha+1), -alpha, DEPTH_ZERO) + : - search(pos, ss+1, -(alpha+1), -alpha, d); - ss->reduction = DEPTH_ZERO; - doFullDepthSearch = (value > alpha); - } + doFullDepthSearch = (value > alpha && ss->reduction != DEPTH_ZERO); + ss->reduction = DEPTH_ZERO; + } + else + doFullDepthSearch = !isPvMove; - // Step 16. Full depth search - if (doFullDepthSearch) - { - alpha = SpNode ? sp->alpha : alpha; - value = newDepth < ONE_PLY ? -qsearch(pos, ss+1, -(alpha+1), -alpha, DEPTH_ZERO) - : - search(pos, ss+1, -(alpha+1), -alpha, newDepth); - - // Step extra. pv search (only in PV nodes) - // Search only for possible new PV nodes, if instead value >= beta then - // parent node fails low with value <= alpha and tries another move. - if (PvNode && value > alpha && (RootNode || value < beta)) - value = newDepth < ONE_PLY ? -qsearch(pos, ss+1, -beta, -alpha, DEPTH_ZERO) - : - search(pos, ss+1, -beta, -alpha, newDepth); - } + // Step 16. Full depth search, when LMR is skipped or fails high + if (doFullDepthSearch) + { + alpha = SpNode ? sp->alpha : alpha; + value = newDepth < ONE_PLY ? -qsearch(pos, ss+1, -(alpha+1), -alpha, DEPTH_ZERO) + : - search(pos, ss+1, -(alpha+1), -alpha, newDepth); } + // Only for PV nodes do a full PV search on the first move or after a fail + // high, in the latter case search only if value < beta, otherwise let the + // parent node to fail low with value <= alpha and to try another move. + if (PvNode && (isPvMove || (value > alpha && (RootNode || value < beta)))) + value = newDepth < ONE_PLY ? -qsearch(pos, ss+1, -beta, -alpha, DEPTH_ZERO) + : - search(pos, ss+1, -beta, -alpha, newDepth); + // Step 17. Undo move pos.undo_move(move); @@ -1186,7 +1191,7 @@ split_point_start: // At split points actual search starts from here // was aborted because the user interrupted the search or because we // ran out of time. In this case, the return value of the search cannot // be trusted, and we don't update the best move and/or PV. - if (RootNode && !StopRequest) + if (RootNode && !Signals.stop) { // Remember searched nodes counts for this move RootMove* rm = Rml.find(move); @@ -1237,7 +1242,7 @@ split_point_start: // At split points actual search starts from here && depth >= Threads.min_split_depth() && bestValue < beta && Threads.available_slave_exists(pos.thread()) - && !StopRequest + && !Signals.stop && !thread.cutoff_occurred()) bestValue = Threads.split(pos, ss, alpha, beta, bestValue, depth, threatMove, moveCount, &mp, NT); @@ -1255,7 +1260,7 @@ split_point_start: // At split points actual search starts from here // Step 21. Update tables // If the search is not aborted, update the transposition table, // history counters, and killer moves. - if (!SpNode && !StopRequest && !thread.cutoff_occurred()) + if (!SpNode && !Signals.stop && !thread.cutoff_occurred()) { move = bestValue <= oldAlpha ? MOVE_NONE : ss->bestMove; vt = bestValue <= oldAlpha ? VALUE_TYPE_UPPER @@ -1680,8 +1685,8 @@ split_point_start: // At split points actual search starts from here Value v = value_from_tt(tte->value(), ply); return ( tte->depth() >= depth - || v >= Max(VALUE_MATE_IN_PLY_MAX, beta) - || v < Min(VALUE_MATED_IN_PLY_MAX, beta)) + || v >= std::max(VALUE_MATE_IN_PLY_MAX, beta) + || v < std::min(VALUE_MATED_IN_PLY_MAX, beta)) && ( ((tte->type() & VALUE_TYPE_LOWER) && v >= beta) || ((tte->type() & VALUE_TYPE_UPPER) && v < beta)); @@ -1726,24 +1731,10 @@ split_point_start: // At split points actual search starts from here } - // update_gains() updates the gains table of a non-capture move given - // the static position evaluation before and after the move. - - void update_gains(const Position& pos, Move m, Value before, Value after) { - - if ( m != MOVE_NULL - && before != VALUE_NONE - && after != VALUE_NONE - && pos.captured_piece_type() == PIECE_TYPE_NONE - && !is_special(m)) - H.update_gain(pos.piece_on(move_to(m)), move_to(m), -(before + after)); - } - - // current_search_time() returns the number of milliseconds which have passed // since the beginning of the current search. - int current_search_time(int set) { + int elapsed_search_time(int set) { static int searchStartTime; @@ -1782,7 +1773,7 @@ split_point_start: // At split points actual search starts from here string speed_to_uci(int64_t nodes) { std::stringstream s; - int t = current_search_time(); + int t = elapsed_search_time(); s << " nodes " << nodes << " nps " << (t > 0 ? int(nodes * 1000 / t) : 0) @@ -1791,6 +1782,7 @@ split_point_start: // At split points actual search starts from here return s.str(); } + // pv_to_uci() returns a string with information on the current PV line // formatted according to UCI specification. @@ -1806,6 +1798,7 @@ split_point_start: // At split points actual search starts from here return s.str(); } + // depth_to_uci() returns a string with information on the current depth and // seldepth formatted according to UCI specification. @@ -1856,6 +1849,7 @@ split_point_start: // At split points actual search starts from here return s.str(); } + // pretty_pv() creates a human-readable string from a position and a PV. // It is used to write search information to the log file (which is created // when the UCI parameter "Use Search Log" is "true"). @@ -1908,104 +1902,10 @@ split_point_start: // At split points actual search starts from here return s.str(); } - // poll() performs two different functions: It polls for user input, and it - // looks at the time consumed so far and decides if it's time to abort the - // search. - - void poll(const Position& pos) { - - static int lastInfoTime; - int t = current_search_time(); - - // Poll for input - if (input_available()) - { - // We are line oriented, don't read single chars - string command; - - if (!std::getline(std::cin, command) || command == "quit") - { - // Quit the program as soon as possible - Limits.ponder = false; - QuitRequest = StopRequest = true; - return; - } - else if (command == "stop") - { - // Stop calculating as soon as possible, but still send the "bestmove" - // and possibly the "ponder" token when finishing the search. - Limits.ponder = false; - StopRequest = true; - } - else if (command == "ponderhit") - { - // The opponent has played the expected move. GUI sends "ponderhit" if - // we were told to ponder on the same move the opponent has played. We - // should continue searching but switching from pondering to normal search. - Limits.ponder = false; - - if (StopOnPonderhit) - StopRequest = true; - } - } - - // Print search information - if (t < 1000) - lastInfoTime = 0; - - else if (lastInfoTime > t) - // HACK: Must be a new search where we searched less than - // NodesBetweenPolls nodes during the first second of search. - lastInfoTime = 0; - - else if (t - lastInfoTime >= 1000) - { - lastInfoTime = t; - - dbg_print_mean(); - dbg_print_hit_rate(); - } - - // Should we stop the search? - if (Limits.ponder) - return; - - bool stillAtFirstMove = FirstRootMove - && !AspirationFailLow - && t > TimeMgr.available_time(); - - bool noMoreTime = t > TimeMgr.maximum_time() - || stillAtFirstMove; - - if ( (Limits.useTimeManagement() && noMoreTime) - || (Limits.maxTime && t >= Limits.maxTime) - || (Limits.maxNodes && pos.nodes_searched() >= Limits.maxNodes)) // FIXME - StopRequest = true; - } - - - // wait_for_stop_or_ponderhit() is called when the maximum depth is reached - // while the program is pondering. The point is to work around a wrinkle in - // the UCI protocol: When pondering, the engine is not allowed to give a - // "bestmove" before the GUI sends it a "stop" or "ponderhit" command. - // We simply wait here until one of these commands is sent, and return, - // after which the bestmove and pondermove will be printed. - - void wait_for_stop_or_ponderhit() { - - string command; - - // Wait for a command from stdin - while ( std::getline(std::cin, command) - && command != "ponderhit" && command != "stop" && command != "quit") {}; - - if (command != "ponderhit" && command != "stop") - QuitRequest = true; // Must be "quit" or getline() returned false - } - // When playing with strength handicap choose best move among the MultiPV set // using a statistical rule dependent on SkillLevel. Idea by Heinz van Saanen. + void do_skill_level(Move* best, Move* ponder) { assert(MultiPV > 1); @@ -2015,9 +1915,9 @@ split_point_start: // At split points actual search starts from here // Rml list is already sorted by score in descending order int s; int max_s = -VALUE_INFINITE; - int size = Min(MultiPV, (int)Rml.size()); + int size = std::min(MultiPV, (int)Rml.size()); int max = Rml[0].score; - int var = Min(max - Rml[size - 1].score, PawnValueMidgame); + int var = std::min(max - Rml[size - 1].score, int(PawnValueMidgame)); int wk = 120 - 2 * SkillLevel; // PRNG sequence should be non deterministic @@ -2050,7 +1950,7 @@ split_point_start: // At split points actual search starts from here /// RootMove and RootMoveList method's definitions - void RootMoveList::init(Position& pos, Move searchMoves[]) { + void RootMoveList::init(Position& pos, Move rootMoves[]) { Move* sm; bestMoveChanges = 0; @@ -2059,11 +1959,11 @@ split_point_start: // At split points actual search starts from here // Generate all legal moves and add them to RootMoveList for (MoveList ml(pos); !ml.end(); ++ml) { - // If we have a searchMoves[] list then verify the move + // If we have a rootMoves[] list then verify the move // is in the list before to add it. - for (sm = searchMoves; *sm && *sm != ml.move(); sm++) {} + for (sm = rootMoves; *sm && *sm != ml.move(); sm++) {} - if (sm != searchMoves && *sm != ml.move()) + if (sm != rootMoves && *sm != ml.move()) continue; RootMove rm; @@ -2084,6 +1984,7 @@ split_point_start: // At split points actual search starts from here return NULL; } + // extract_pv_from_tt() builds a PV by adding moves from the transposition table. // We consider also failing high nodes and not only VALUE_TYPE_EXACT nodes. This // allow to always have a ponder move even when we fail high at root and also a @@ -2118,6 +2019,7 @@ split_point_start: // At split points actual search starts from here do pos.undo_move(pv[--ply]); while (ply); } + // insert_pv_in_tt() is called at the end of a search iteration, and inserts // the PV back into the TT. This makes sure the old PV moves are searched // first, even if the old TT entries have been overwritten. @@ -2148,20 +2050,8 @@ split_point_start: // At split points actual search starts from here do pos.undo_move(pv[--ply]); while (ply); } -} // namespace - - -// Little helper used by idle_loop() to check that all the slave threads of a -// split point have finished searching. - -static bool all_slaves_finished(SplitPoint* sp) { - - for (int i = 0; i < Threads.size(); i++) - if (sp->is_slave[i]) - return false; - return true; -} +} // namespace // Thread::idle_loop() is where the thread is parked when it has no work to do. @@ -2191,7 +2081,7 @@ void Thread::idle_loop(SplitPoint* sp) { lock_grab(&sleepLock); // If we are master and all slaves have finished don't go to sleep - if (sp && all_slaves_finished(sp)) + if (sp && Threads.split_point_finished(sp)) { lock_release(&sleepLock); break; @@ -2243,7 +2133,7 @@ void Thread::idle_loop(SplitPoint* sp) { // If this thread is the master of a split point and all slaves have // finished their work at this split point, return from the idle loop. - if (sp && all_slaves_finished(sp)) + if (sp && Threads.split_point_finished(sp)) { // Because sp->is_slave[] is reset under lock protection, // be sure sp->lock has been released before to return. @@ -2253,3 +2143,37 @@ void Thread::idle_loop(SplitPoint* sp) { } } } + + +// do_timer_event() is called by the timer thread when the timer triggers + +void do_timer_event() { + + static int lastInfoTime; + int e = elapsed_search_time(); + + // Print debug information every one second + if (!lastInfoTime || get_system_time() - lastInfoTime >= 1000) + { + lastInfoTime = get_system_time(); + + dbg_print_mean(); + dbg_print_hit_rate(); + } + + // Should we stop the search? + if (Limits.ponder) + return; + + bool stillAtFirstMove = Signals.firstRootMove + && !Signals.failedLowAtRoot + && e > TimeMgr.available_time(); + + bool noMoreTime = e > TimeMgr.maximum_time() + || stillAtFirstMove; + + if ( (Limits.useTimeManagement() && noMoreTime) + || (Limits.maxTime && e >= Limits.maxTime) + /* missing nodes limit */ ) // FIXME + Signals.stop = true; +}