X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=0ca539ae235797afa29867368938a3a948f0aaab;hp=b781bb770864aa63d52f1050b316f9c052ec86c2;hb=d543a64cc7fc06daed275b332b10ea06ba738001;hpb=da6e53a436abcd4ac747c89d4496e4195109d908 diff --git a/src/search.cpp b/src/search.cpp index b781bb77..0ca539ae 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -17,14 +17,14 @@ along with this program. If not, see . */ +#include #include #include +#include #include #include -#include #include #include -#include #include "book.h" #include "evaluate.h" @@ -42,12 +42,10 @@ namespace Search { volatile SignalsType Signals; LimitsType Limits; - std::vector RootMoves; + std::vector SearchMoves; Position RootPosition; } -using std::cout; -using std::endl; using std::string; using namespace Search; @@ -60,15 +58,21 @@ namespace { enum NodeType { Root, PV, NonPV, SplitPointRoot, SplitPointPV, SplitPointNonPV }; // RootMove struct is used for moves at the root of the tree. For each root - // move, we store a score, a node count, and a PV (really a refutation - // in the case of moves which fail low). Score is normally set at - // -VALUE_INFINITE for all non-pv moves. + // move we store a score, a node count, and a PV (really a refutation in the + // case of moves which fail low). Score is normally set at -VALUE_INFINITE for + // all non-pv moves. struct RootMove { - // RootMove::operator<() is the comparison function used when - // sorting the moves. A move m1 is considered to be better - // than a move m2 if it has an higher score + RootMove(){} + RootMove(Move m) { + nodes = 0; + score = prevScore = -VALUE_INFINITE; + pv.push_back(m); + pv.push_back(MOVE_NONE); + } + bool operator<(const RootMove& m) const { return score < m.score; } + bool operator==(const Move& m) const { return pv[0] == m; } void extract_pv_from_tt(Position& pos); void insert_pv_in_tt(Position& pos); @@ -79,15 +83,6 @@ namespace { std::vector pv; }; - // RootMoveList struct is mainly a std::vector of RootMove objects - struct RootMoveList : public std::vector { - - void init(Position& pos, Move rootMoves[]); - RootMove* find(const Move& m, int startIndex = 0); - - int bestMoveChanges; - }; - /// Constants @@ -147,33 +142,24 @@ namespace { /// Namespace variables - // Root move list - RootMoveList Rml; - - // MultiPV mode - size_t MultiPV, UCIMultiPV, MultiPVIdx; - - // Time management variables + std::vector RootMoves; + size_t MultiPV, UCIMultiPV, PVIdx; TimeManager TimeMgr; - - // Skill level adjustment + int BestMoveChanges; int SkillLevel; - bool SkillLevelEnabled; - - // History table + bool SkillLevelEnabled, Chess960; History H; /// Local functions - Move id_loop(Position& pos, Move rootMoves[], Move* ponderMove); - template Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth); template Value qsearch(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth); + void id_loop(Position& pos); bool check_is_dangerous(Position &pos, Move move, Value futilityBase, Value beta, Value *bValue); bool connected_moves(const Position& pos, Move m1, Move m2); Value value_to_tt(Value v, int ply); @@ -181,19 +167,15 @@ namespace { bool can_return_tt(const TTEntry* tte, Depth depth, Value beta, int ply); 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 do_skill_level(Move* best, Move* ponder); - + Move do_skill_level(); int elapsed_time(bool reset = false); 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); - - // 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 - // we simply create and use a standard MovePicker object. + void pv_info_to_log(Position& pos, int depth, Value score, int time, Move pv[]); + void pv_info_to_uci(const Position& pos, int depth, Value alpha, Value beta); + + // MovePickerExt class template extends MovePicker and allows to choose at + // compile time the proper moves source according to the type of node. In the + // default case we simply create and use a standard MovePicker object. template struct MovePickerExt : public MovePicker { MovePickerExt(const Position& p, Move ttm, Depth d, const History& h, Stack* ss, Value b) @@ -210,28 +192,6 @@ namespace { MovePicker* mp; }; - // Overload operator<<() to make it easier to print moves in a coordinate - // notation compatible with UCI protocol. - std::ostream& operator<<(std::ostream& os, Move m) { - - bool chess960 = (os.iword(0) != 0); // See set960() - return os << move_to_uci(m, chess960); - } - - // When formatting a move for std::cout we must know if we are in Chess960 - // or not. To keep using the handy operator<<() on the move the trick is to - // embed this flag in the stream itself. Function-like named enum set960 is - // used as a custom manipulator and the stream internal general-purpose array, - // accessed through ios_base::iword(), is used to pass the flag to the move's - // operator<<() that will read it to properly format castling moves. - enum set960 {}; - - std::ostream& operator<< (std::ostream& os, const set960& f) { - - os.iword(0) = int(f); - return os; - } - // is_dangerous() checks whether a move belongs to some classes of known // 'dangerous' moves so that we avoid to prune it. FORCE_INLINE bool is_dangerous(const Position& pos, Move m, bool captureOrPromotion) { @@ -259,7 +219,7 @@ namespace { } // namespace -/// init_search() is called during startup to initialize various lookup tables +/// Search::init() is called during startup to initialize various lookup tables void Search::init() { @@ -286,23 +246,20 @@ void Search::init() { } -/// 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. +/// 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 Search::perft(Position& pos, Depth depth) { StateInfo st; int64_t sum = 0; - // Generate all legal moves MoveList ml(pos); - // If we are at the last ply we don't need to do and undo - // the moves, just to count them. + // At the last ply just return the number of moves (leaf nodes) if (depth <= ONE_PLY) return ml.size(); - // Loop through all legal moves CheckInfo ci(pos); for ( ; !ml.end(); ++ml) { @@ -314,36 +271,41 @@ int64_t Search::perft(Position& pos, Depth depth) { } -/// think() is the external interface to Stockfish's search, and is called by the -/// main thread when the program receives the UCI 'go' command. It searches from -/// RootPosition and at the end prints the "bestmove" to output. +/// Search::think() is the external interface to Stockfish's search, and is +/// called by the main thread when the program receives the UCI 'go' command. It +/// searches from RootPosition and at the end prints the "bestmove" to output. void Search::think() { static Book book; // Defined static to initialize the PRNG only once Position& pos = RootPosition; - - // Reset elapsed search time + Chess960 = pos.is_chess960(); elapsed_time(true); + TimeMgr.init(Limits, pos.startpos_ply_counter()); + TT.new_search(); + H.clear(); + RootMoves.clear(); + + // Populate RootMoves with all the legal moves (default) or, if a SearchMoves + // is given, with the subset of legal moves to search. + for (MoveList ml(pos); !ml.end(); ++ml) + if ( SearchMoves.empty() + || count(SearchMoves.begin(), SearchMoves.end(), ml.move())) + RootMoves.push_back(RootMove(ml.move())); - // 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()) { if (Options["Book File"].value() != book.name()) book.open(Options["Book File"].value()); Move bookMove = book.probe(pos, Options["Best Book Move"].value()); - if (bookMove != MOVE_NONE) - { - if (!Signals.stop && (Limits.ponder || Limits.infinite)) - Threads.wait_for_stop_or_ponderhit(); - cout << "bestmove " << bookMove << endl; - return; + if ( bookMove != MOVE_NONE + && count(RootMoves.begin(), RootMoves.end(), bookMove)) + { + std::swap(RootMoves[0], *find(RootMoves.begin(), RootMoves.end(), bookMove)); + goto finish; } } @@ -351,9 +313,7 @@ void Search::think() { read_evaluation_uci_options(pos.side_to_move()); Threads.read_uci_options(); - // Set a new TT size if changed TT.set_size(Options["Hash"].value()); - if (Options["Clear Hash"].value()) { Options["Clear Hash"].set_value("false"); @@ -361,14 +321,13 @@ void Search::think() { } UCIMultiPV = Options["MultiPV"].value(); - SkillLevel = Options["Skill Level"].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 ? std::max(UCIMultiPV, 4U) : UCIMultiPV); + MultiPV = (SkillLevelEnabled ? std::max(UCIMultiPV, (size_t)4) : UCIMultiPV); - // Write current search header to log file if (Options["Use Search Log"].value()) { Log log(Options["Search Log Filename"].value()); @@ -378,10 +337,9 @@ void Search::think() { << " time: " << Limits.time << " increment: " << Limits.increment << " moves to go: " << Limits.movesToGo - << endl; + << std::endl; } - // Wake up needed threads and reset maxPly counter for (int i = 0; i < Threads.size(); i++) { Threads[i].maxPly = 0; @@ -390,24 +348,18 @@ void Search::think() { // 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, &RootMoves[0], &ponderMove); + // We're ready to start searching. Call the iterative deepening loop function + id_loop(pos); - // Stop timer, no need to check for available time any more + // Stop timer and send all the slaves to sleep, if not already sleeping Threads.set_timer(0); - - // 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 e = elapsed_time(); @@ -415,29 +367,26 @@ void Search::think() { Log log(Options["Search Log Filename"].value()); log << "Nodes: " << pos.nodes_searched() << "\nNodes/second: " << (e > 0 ? pos.nodes_searched() * 1000 / e : 0) - << "\nBest move: " << move_to_san(pos, bestMove); + << "\nBest move: " << move_to_san(pos, RootMoves[0].pv[0]); StateInfo st; - pos.do_move(bestMove, st); - log << "\nPonder move: " << move_to_san(pos, ponderMove) << endl; - pos.undo_move(bestMove); // Return from think() with unchanged position + pos.do_move(RootMoves[0].pv[0], st); + log << "\nPonder move: " << move_to_san(pos, RootMoves[0].pv[1]) << std::endl; + pos.undo_move(RootMoves[0].pv[0]); } +finish: + // 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; - - // UCI protol is not clear on allowing sending an empty ponder move, instead - // it is clear that ponder move is optional. So skip it if empty. - if (ponderMove != MOVE_NONE) - cout << " ponder " << ponderMove; - - cout << endl; + // Best move could be MOVE_NONE when searching on a stalemate position + printf("bestmove %s ponder %s\n", + move_to_uci(RootMoves[0].pv[0], Chess960).c_str(), + move_to_uci(RootMoves[0].pv[1], Chess960).c_str()); } @@ -447,60 +396,49 @@ 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 rootMoves[], Move* ponderMove) { + void id_loop(Position& pos) { Stack ss[PLY_MAX_PLUS_2]; - Value bestValues[PLY_MAX_PLUS_2]; - int bestMoveChanges[PLY_MAX_PLUS_2]; - int depth, aspirationDelta; - Value bestValue, alpha, beta; - Move bestMove, skillBest, skillPonder; + int depth, prevBestMoveChanges; + Value bestValue, alpha, beta, delta; bool bestMoveNeverChanged = true; + Move skillBest = MOVE_NONE; - // Initialize stuff before a new search memset(ss, 0, 4 * sizeof(Stack)); - TT.new_search(); - H.clear(); - *ponderMove = bestMove = skillBest = skillPonder = MOVE_NONE; - depth = aspirationDelta = 0; - bestValue = alpha = -VALUE_INFINITE, beta = VALUE_INFINITE; + depth = BestMoveChanges = 0; + bestValue = delta = -VALUE_INFINITE; ss->currentMove = MOVE_NULL; // Hack to skip update gains - // Moves to search are verified and copied - Rml.init(pos, rootMoves); - - // Handle special case of searching on a mate/stalemate position - if (Rml.empty()) + // Handle the special case of a mate/stalemate position + if (RootMoves.empty()) { - cout << "info" << depth_to_uci(DEPTH_ZERO) - << score_to_uci(pos.in_check() ? -VALUE_MATE : VALUE_DRAW, alpha, beta) << endl; + printf("info depth 0%s\n", + score_to_uci(pos.in_check() ? -VALUE_MATE : VALUE_DRAW).c_str()); - return MOVE_NONE; + RootMoves.push_back(MOVE_NONE); + return; } // Iterative deepening loop until requested to stop or target depth reached 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++) - Rml[i].prevScore = Rml[i].score; + // Save last iteration's scores before first PV line is searched and all + // the move scores but the (new) PV are set to -VALUE_INFINITE. + for (size_t i = 0; i < RootMoves.size(); i++) + RootMoves[i].prevScore = RootMoves[i].score; - Rml.bestMoveChanges = 0; + prevBestMoveChanges = BestMoveChanges; + BestMoveChanges = 0; // MultiPV loop. We perform a full root search for each PV line - for (MultiPVIdx = 0; MultiPVIdx < std::min(MultiPV, Rml.size()); MultiPVIdx++) + for (PVIdx = 0; PVIdx < std::min(MultiPV, RootMoves.size()); PVIdx++) { - // Calculate dynamic aspiration window based on previous iterations - if (depth >= 5 && abs(Rml[MultiPVIdx].prevScore) < VALUE_KNOWN_WIN) + // Set aspiration window default width + if (depth >= 5 && abs(RootMoves[PVIdx].prevScore) < VALUE_KNOWN_WIN) { - int prevDelta1 = bestValues[depth - 1] - bestValues[depth - 2]; - int prevDelta2 = bestValues[depth - 2] - bestValues[depth - 3]; - - aspirationDelta = std::min(std::max(abs(prevDelta1) + abs(prevDelta2) / 2, 16), 24); - aspirationDelta = (aspirationDelta + 7) / 8 * 8; // Round to match grainSize - - alpha = std::max(Rml[MultiPVIdx].prevScore - aspirationDelta, -VALUE_INFINITE); - beta = std::min(Rml[MultiPVIdx].prevScore + aspirationDelta, VALUE_INFINITE); + delta = Value(16); + alpha = RootMoves[PVIdx].prevScore - delta; + beta = RootMoves[PVIdx].prevScore + delta; } else { @@ -521,101 +459,77 @@ namespace { // we want to keep the same order for all the moves but the new // PV that goes to the front. Note that in case of MultiPV search // the already searched PV lines are preserved. - sort(Rml.begin() + MultiPVIdx, Rml.end()); + sort(RootMoves.begin() + PVIdx, RootMoves.end()); // In case we have found an exact score and we are going to leave // 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 && bestValue > alpha && bestValue < beta) - sort(Rml.begin(), Rml.begin() + MultiPVIdx); + if (PVIdx && bestValue > alpha && bestValue < beta) + sort(RootMoves.begin(), RootMoves.begin() + PVIdx); - // Write PV back to transposition table in case the relevant entries - // have been overwritten during the search. - for (size_t i = 0; i <= MultiPVIdx; i++) - Rml[i].insert_pv_in_tt(pos); + // Write PV back to transposition table in case the relevant + // entries have been overwritten during the search. + for (size_t i = 0; i <= PVIdx; i++) + RootMoves[i].insert_pv_in_tt(pos); - // 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 search has been stopped exit the aspiration window loop. + // Sorting and writing PV back to TT is safe becuase RootMoves + // is still valid, although refers to previous iteration. 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 we have a fail high/low and we are deep in the search. if ((bestValue > alpha && bestValue < beta) || elapsed_time() > 2000) - for (size_t i = 0; i < std::min(UCIMultiPV, Rml.size()); i++) - { - bool updated = (i <= MultiPVIdx); - - if (depth == 1 && !updated) - continue; - - Depth d = (updated ? depth : depth - 1) * ONE_PLY; - Value s = (updated ? Rml[i].score : Rml[i].prevScore); - - cout << "info" - << depth_to_uci(d) - << (i == MultiPVIdx ? score_to_uci(s, alpha, beta) : score_to_uci(s)) - << speed_to_uci(pos.nodes_searched()) - << pv_to_uci(&Rml[i].pv[0], i + 1, pos.is_chess960()) - << endl; - } + pv_info_to_uci(pos, depth, alpha, beta); // In case of failing high/low increase aspiration window and // research, otherwise exit the fail high/low loop. if (bestValue >= beta) { - beta = std::min(beta + aspirationDelta, VALUE_INFINITE); - aspirationDelta += aspirationDelta / 2; + beta += delta; + delta += delta / 2; } else if (bestValue <= alpha) { Signals.failedLowAtRoot = true; Signals.stopOnPonderhit = false; - alpha = std::max(alpha - aspirationDelta, -VALUE_INFINITE); - aspirationDelta += aspirationDelta / 2; + alpha -= delta; + delta += delta / 2; } else break; + assert(alpha >= -VALUE_INFINITE && beta <= VALUE_INFINITE); + } while (abs(bestValue) < VALUE_KNOWN_WIN); } - // Collect info about search result - bestMove = Rml[0].pv[0]; - *ponderMove = Rml[0].pv[1]; - bestValues[depth] = bestValue; - bestMoveChanges[depth] = Rml.bestMoveChanges; - - // Skills: Do we need to pick now the best and the ponder moves ? + // Skills: Do we need to pick now the best move ? if (SkillLevelEnabled && depth == 1 + SkillLevel) - do_skill_level(&skillBest, &skillPonder); + skillBest = do_skill_level(); if (Options["Use Search Log"].value()) - { - Log log(Options["Search Log Filename"].value()); - log << pretty_pv(pos, depth, bestValue, elapsed_time(), &Rml[0].pv[0]) << endl; - } + pv_info_to_log(pos, depth, bestValue, elapsed_time(), &RootMoves[0].pv[0]); // Filter out startup noise when monitoring best move stability - if (depth > 2 && bestMoveChanges[depth]) + if (depth > 2 && BestMoveChanges) bestMoveNeverChanged = false; // Do we have time for the next iteration? Can we stop searching now? if (!Signals.stop && !Signals.stopOnPonderhit && Limits.useTimeManagement()) { - bool stop = false; // Local variable instead of the volatile Signals.stop + bool stop = false; // Local variable, not the volatile Signals.stop // Take in account some extra time if the best move has changed if (depth > 4 && depth < 50) - TimeMgr.pv_instability(bestMoveChanges[depth], bestMoveChanges[depth - 1]); + TimeMgr.pv_instability(BestMoveChanges, prevBestMoveChanges); - // 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. + // 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 (elapsed_time() > (TimeMgr.available_time() * 62) / 100) stop = true; @@ -626,7 +540,7 @@ namespace { || elapsed_time() > (TimeMgr.available_time() * 40) / 100)) { Value rBeta = bestValue - EasyMoveMargin; - (ss+1)->excludedMove = bestMove; + (ss+1)->excludedMove = RootMoves[0].pv[0]; (ss+1)->skipNullMove = true; Value v = search(pos, ss+1, rBeta - 1, rBeta, (depth * ONE_PLY) / 2); (ss+1)->skipNullMove = false; @@ -648,17 +562,14 @@ namespace { } } - // When using skills overwrite best and ponder moves with the sub-optimal ones + // When using skills swap best PV line with the sub-optimal one if (SkillLevelEnabled) { if (skillBest == MOVE_NONE) // Still unassigned ? - do_skill_level(&skillBest, &skillPonder); + skillBest = do_skill_level(); - bestMove = skillBest; - *ponderMove = skillPonder; + std::swap(RootMoves[0], *find(RootMoves.begin(), RootMoves.end(), skillBest)); } - - return bestMove; } @@ -743,7 +654,7 @@ namespace { excludedMove = ss->excludedMove; posKey = excludedMove ? pos.get_exclusion_key() : pos.get_key(); tte = TT.probe(posKey); - ttMove = RootNode ? Rml[MultiPVIdx].pv[0] : tte ? tte->move() : MOVE_NONE; + ttMove = RootNode ? RootMoves[PVIdx].pv[0] : tte ? tte->move() : MOVE_NONE; // At PV nodes we check for exact scores, while at non-PV nodes we check for // a fail high/low. Biggest advantage at probing at PV nodes is to have a @@ -932,7 +843,6 @@ namespace { split_point_start: // At split points actual search starts from here - // Initialize a MovePicker object for the current position MovePickerExt mp(pos, ttMove, depth, H, ss, PvNode ? -VALUE_INFINITE : beta); CheckInfo ci(pos); ss->bestMove = MOVE_NONE; @@ -941,13 +851,16 @@ split_point_start: // At split points actual search starts from here && !SpNode && depth >= SingularExtensionDepth[PvNode] && ttMove != MOVE_NONE - && !excludedMove // Do not allow recursive singular extension search + && !excludedMove // Recursive singular search is not allowed && (tte->type() & VALUE_TYPE_LOWER) && tte->depth() >= depth - 3 * ONE_PLY; if (SpNode) { lock_grab(&(sp->lock)); bestValue = sp->bestValue; + moveCount = sp->moveCount; + + assert(bestValue > -VALUE_INFINITE && moveCount > 0); } // Step 11. Loop through moves @@ -964,7 +877,7 @@ split_point_start: // At split points actual search starts from here // At root obey the "searchmoves" option and skip moves not listed in Root // Move List, as a consequence any illegal move is also skipped. In MultiPV // mode we also skip PV moves which have been already searched. - if (RootNode && !Rml.find(move, MultiPVIdx)) + if (RootNode && !count(RootMoves.begin() + PVIdx, RootMoves.end(), move)) continue; // At PV and SpNode nodes we want all moves to be legal since the beginning @@ -981,17 +894,12 @@ split_point_start: // At split points actual search starts from here if (RootNode) { - // This is used by time management 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 && elapsed_time() > 2000) - cout << "info" << depth_to_uci(depth) - << " currmove " << move - << " currmovenumber " << moveCount + MultiPVIdx << endl; + printf("info depth %i currmove %s currmovenumber %i\n", depth / ONE_PLY, + move_to_uci(move, Chess960).c_str(), moveCount + PVIdx); } isPvMove = (PvNode && moveCount <= 1); @@ -1042,12 +950,12 @@ split_point_start: // At split points actual search starts from here && !inCheck && !dangerous && move != ttMove - && !is_castle(move)) + && !is_castle(move) + && (bestValue > VALUE_MATED_IN_PLY_MAX || bestValue == -VALUE_INFINITE)) { // Move count based pruning if ( moveCount >= futility_move_count(depth) - && (!threatMove || !connected_threat(pos, move, threatMove)) - && bestValue > VALUE_MATED_IN_PLY_MAX) // FIXME bestValue is racy + && (!threatMove || !connected_threat(pos, move, threatMove))) { if (SpNode) lock_grab(&(sp->lock)); @@ -1065,20 +973,13 @@ split_point_start: // At split points actual search starts from here if (futilityValue < beta) { if (SpNode) - { lock_grab(&(sp->lock)); - if (futilityValue > sp->bestValue) - sp->bestValue = bestValue = futilityValue; - } - else if (futilityValue > bestValue) - bestValue = futilityValue; continue; } // Prune moves with negative SEE at low depths if ( predictedDepth < 2 * ONE_PLY - && bestValue > VALUE_MATED_IN_PLY_MAX && pos.see_sign(move) < 0) { if (SpNode) @@ -1159,30 +1060,28 @@ split_point_start: // At split points actual search starts from here // be trusted, and we don't update the best move and/or PV. if (RootNode && !Signals.stop) { - // Remember searched nodes counts for this move - RootMove* rm = Rml.find(move); - rm->nodes += pos.nodes_searched() - nodes; + RootMove& rm = *find(RootMoves.begin(), RootMoves.end(), move); + rm.nodes += pos.nodes_searched() - nodes; // PV move or new best move ? if (isPvMove || value > alpha) { - // Update PV - rm->score = value; - rm->extract_pv_from_tt(pos); + rm.score = value; + rm.extract_pv_from_tt(pos); // We record how often the best move has been changed in each // iteration. This information is used for time management: When // the best move changes frequently, we allocate some more time. if (!isPvMove && MultiPV == 1) - Rml.bestMoveChanges++; + BestMoveChanges++; } else // All other moves but the PV are set to the lowest value, this // is not a problem when sorting becuase sort is stable and move // position in the list is preserved, just the PV is pushed up. - rm->score = -VALUE_INFINITE; + rm.score = -VALUE_INFINITE; - } // RootNode + } if (value > bestValue) { @@ -1220,12 +1119,19 @@ split_point_start: // At split points actual search starts from here // case of StopRequest or thread.cutoff_occurred() are set, but this is // harmless because return value is discarded anyhow in the parent nodes. // If we are in a singular extension search then return a fail low score. - if (!SpNode && !moveCount) + if (!moveCount) return excludedMove ? oldAlpha : inCheck ? value_mated_in(ss->ply) : VALUE_DRAW; + // If we have pruned all the moves without searching return a fail-low score + if (bestValue == -VALUE_INFINITE) + { + assert(!playedMoveCount); + + bestValue = alpha; + } + // Step 21. Update tables - // If the search is not aborted, update the transposition table, - // history counters, and killer moves. + // Update transposition table entry, killers and history if (!SpNode && !Signals.stop && !thread.cutoff_occurred()) { move = bestValue <= oldAlpha ? MOVE_NONE : ss->bestMove; @@ -1234,16 +1140,27 @@ split_point_start: // At split points actual search starts from here TT.store(posKey, value_to_tt(bestValue, ss->ply), vt, depth, move, ss->eval, ss->evalMargin); - // Update killers and history only for non capture moves that fails high + // Update killers and history for non capture cut-off moves if ( bestValue >= beta - && !pos.is_capture_or_promotion(move)) + && !pos.is_capture_or_promotion(move) + && !inCheck) { if (move != ss->killers[0]) { ss->killers[1] = ss->killers[0]; ss->killers[0] = move; } - update_history(pos, move, depth, movesSearched, playedMoveCount); + + // Increase history value of the cut-off move + Value bonus = Value(int(depth) * int(depth)); + H.add(pos.piece_on(move_from(move)), move_to(move), bonus); + + // Decrease history of all the other played non-capture moves + for (int i = 0; i < playedMoveCount - 1; i++) + { + Move m = movesSearched[i]; + H.add(pos.piece_on(move_from(m)), move_to(m), -bonus); + } } } @@ -1260,6 +1177,7 @@ split_point_start: // At split points actual search starts from here return bestValue; } + // qsearch() is the quiescence search function, which is called by the main // search function when the remaining depth is zero (or, to be more precise, // less than ONE_PLY). @@ -1340,7 +1258,6 @@ split_point_start: // At split points actual search starts from here if (PvNode && bestValue > alpha) alpha = bestValue; - // Futility pruning parameters, not needed when in check futilityBase = ss->eval + evalMargin + FutilityMarginQS; enoughMaterial = pos.non_pawn_material(pos.side_to_move()) > RookValueMidgame; } @@ -1422,7 +1339,6 @@ split_point_start: // At split points actual search starts from here if (!pos.pl_move_is_legal(move, ci.pinned)) continue; - // Update current move ss->currentMove = move; // Make and search the move @@ -1643,8 +1559,8 @@ split_point_start: // At split points actual search starts from here } - // can_return_tt() returns true if a transposition table score - // can be used to cut-off at a given point in search. + // can_return_tt() returns true if a transposition table score can be used to + // cut-off at a given point in search. bool can_return_tt(const TTEntry* tte, Depth depth, Value beta, int ply) { @@ -1659,8 +1575,8 @@ split_point_start: // At split points actual search starts from here } - // refine_eval() returns the transposition table score if - // possible otherwise falls back on static position evaluation. + // refine_eval() returns the transposition table score if possible, otherwise + // falls back on static position evaluation. Value refine_eval(const TTEntry* tte, Value defaultEval, int ply) { @@ -1676,27 +1592,6 @@ split_point_start: // At split points actual search starts from here } - // update_history() registers a good move that produced a beta-cutoff - // in history and marks as failures all the other moves of that ply. - - void update_history(const Position& pos, Move move, Depth depth, - Move movesSearched[], int moveCount) { - Move m; - Value bonus = Value(int(depth) * int(depth)); - - H.update(pos.piece_on(move_from(move)), move_to(move), bonus); - - for (int i = 0; i < moveCount - 1; i++) - { - m = movesSearched[i]; - - assert(m != move); - - H.update(pos.piece_on(move_from(m)), move_to(m), -bonus); - } - } - - // current_search_time() returns the number of milliseconds which have passed // since the beginning of the current search. @@ -1733,55 +1628,49 @@ split_point_start: // At split points actual search starts from here } - // speed_to_uci() returns a string with time stats of current search suitable - // to be sent to UCI gui. + // pv_info_to_uci() sends search info to GUI. UCI protocol requires to send all + // the PV lines also if are still to be searched and so refer to the previous + // search score. - string speed_to_uci(int64_t nodes) { + void pv_info_to_uci(const Position& pos, int depth, Value alpha, Value beta) { - std::stringstream s; int t = elapsed_time(); - - s << " nodes " << nodes - << " nps " << (t > 0 ? int(nodes * 1000 / t) : 0) - << " time " << t; - - return s.str(); - } - - - // pv_to_uci() returns a string with information on the current PV line - // formatted according to UCI specification. - - string pv_to_uci(const Move pv[], int pvNum, bool chess960) { - + int selDepth = 0; std::stringstream s; - s << " multipv " << pvNum << " pv " << set960(chess960); - - for ( ; *pv != MOVE_NONE; pv++) - s << *pv << " "; + for (int i = 0; i < Threads.size(); i++) + if (Threads[i].maxPly > selDepth) + selDepth = Threads[i].maxPly; - return s.str(); - } + for (size_t i = 0; i < std::min(UCIMultiPV, RootMoves.size()); i++) + { + bool updated = (i <= PVIdx); + if (depth == 1 && !updated) + continue; - // depth_to_uci() returns a string with information on the current depth and - // seldepth formatted according to UCI specification. + int d = (updated ? depth : depth - 1); + Value v = (updated ? RootMoves[i].score : RootMoves[i].prevScore); - string depth_to_uci(Depth depth) { + s << "info depth " << d + << " seldepth " << selDepth + << (i == PVIdx ? score_to_uci(v, alpha, beta) : score_to_uci(v)) + << " nodes " << pos.nodes_searched() + << " nps " << (t > 0 ? pos.nodes_searched() * 1000 / t : 0) + << " time " << t + << " multipv " << i + 1 << " pv"; - std::stringstream s; + for (int j = 0; RootMoves[i].pv[j] != MOVE_NONE; j++) + s << " " << move_to_uci(RootMoves[i].pv[j], Chess960); - // Retrieve max searched depth among threads - int selDepth = 0; - for (int i = 0; i < Threads.size(); i++) - if (Threads[i].maxPly > selDepth) - selDepth = Threads[i].maxPly; + printf("%s\n", s.str().c_str()); // Much faster than std::cout + } + } - s << " depth " << depth / ONE_PLY << " seldepth " << selDepth; - return s.str(); - } + // pv_info_to_log() writes human-readable search information to the log file + // (which is created when the UCI parameter "Use Search Log" is "true"). It + // uses the two below helpers to pretty format time and score respectively. string time_to_string(int millisecs) { @@ -1797,7 +1686,8 @@ split_point_start: // At split points actual search starts from here if (hours) s << hours << ':'; - s << std::setfill('0') << std::setw(2) << minutes << ':' << std::setw(2) << seconds; + s << std::setfill('0') << std::setw(2) << minutes << ':' + << std::setw(2) << seconds; return s.str(); } @@ -1810,144 +1700,105 @@ split_point_start: // At split points actual search starts from here else if (v <= VALUE_MATED_IN_PLY_MAX) s << "-#" << (VALUE_MATE + v) / 2; else - s << std::setprecision(2) << std::fixed << std::showpos << float(v) / PawnValueMidgame; + s << std::setprecision(2) << std::fixed << std::showpos + << float(v) / PawnValueMidgame; 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"). - - string pretty_pv(Position& pos, int depth, Value value, int time, Move pv[]) { + void pv_info_to_log(Position& pos, int depth, Value value, int time, Move pv[]) { const int64_t K = 1000; const int64_t M = 1000000; - const int startColumn = 28; - const size_t maxLength = 80 - startColumn; StateInfo state[PLY_MAX_PLUS_2], *st = state; Move* m = pv; - string san; + string san, padding; + size_t length; std::stringstream s; - size_t length = 0; - // First print depth, score, time and searched nodes... - s << set960(pos.is_chess960()) - << std::setw(2) << depth + s << std::setw(2) << depth << std::setw(8) << score_to_string(value) << std::setw(8) << time_to_string(time); if (pos.nodes_searched() < M) s << std::setw(8) << pos.nodes_searched() / 1 << " "; + else if (pos.nodes_searched() < K * M) s << std::setw(7) << pos.nodes_searched() / K << "K "; + else s << std::setw(7) << pos.nodes_searched() / M << "M "; - // ...then print the full PV line in short algebraic notation + padding = string(s.str().length(), ' '); + length = padding.length(); + while (*m != MOVE_NONE) { san = move_to_san(pos, *m); - length += san.length() + 1; - if (length > maxLength) + if (length + san.length() > 80) { - length = san.length() + 1; - s << "\n" + string(startColumn, ' '); + s << "\n" + padding; + length = padding.length(); } + s << san << ' '; + length += san.length() + 1; pos.do_move(*m++, *st++); } - // Restore original position before to leave - while (m != pv) pos.undo_move(*--m); + while (m != pv) + pos.undo_move(*--m); - return s.str(); + Log l(Options["Search Log Filename"].value()); + l << s.str() << std::endl; } // 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) { + Move do_skill_level() { assert(MultiPV > 1); static RKISS rk; - // Rml list is already sorted by score in descending order - int s; - size_t size = std::min(MultiPV, Rml.size()); - int max_s = -VALUE_INFINITE; - int max = Rml[0].score; - int var = std::min(max - Rml[size - 1].score, int(PawnValueMidgame)); - int wk = 120 - 2 * SkillLevel; - - // PRNG sequence should be non deterministic + // PRNG sequence should be not deterministic for (int i = abs(get_system_time() % 50); i > 0; i--) rk.rand(); - // Choose best move. For each move's score we add two terms both dependent - // on wk, one deterministic and bigger for weaker moves, and one random, + // RootMoves are already sorted by score in descending order + size_t size = std::min(MultiPV, RootMoves.size()); + int variance = std::min(RootMoves[0].score - RootMoves[size - 1].score, PawnValueMidgame); + int weakness = 120 - 2 * SkillLevel; + int max_s = -VALUE_INFINITE; + Move best = MOVE_NONE; + + // Choose best move. For each move score we add two terms both dependent on + // weakness, one deterministic and bigger for weaker moves, and one random, // then we choose the move with the resulting highest score. for (size_t i = 0; i < size; i++) { - s = Rml[i].score; + int s = RootMoves[i].score; // Don't allow crazy blunders even at very low skills - if (i > 0 && Rml[i-1].score > s + EasyMoveMargin) + if (i > 0 && RootMoves[i-1].score > s + EasyMoveMargin) break; - // This is our magical formula - s += ((max - s) * wk + var * (rk.rand() % wk)) / 128; + // This is our magic formula + s += ( weakness * int(RootMoves[0].score - s) + + variance * (rk.rand() % weakness)) / 128; if (s > max_s) { max_s = s; - *best = Rml[i].pv[0]; - *ponder = Rml[i].pv[1]; + best = RootMoves[i].pv[0]; } } - } - - - /// RootMove and RootMoveList method's definitions - - void RootMoveList::init(Position& pos, Move rootMoves[]) { - - Move* sm; - bestMoveChanges = 0; - clear(); - - // Generate all legal moves and add them to RootMoveList - for (MoveList ml(pos); !ml.end(); ++ml) - { - // If we have a rootMoves[] list then verify the move - // is in the list before to add it. - for (sm = rootMoves; *sm && *sm != ml.move(); sm++) {} - - if (sm != rootMoves && *sm != ml.move()) - continue; - - RootMove rm; - rm.pv.push_back(ml.move()); - rm.pv.push_back(MOVE_NONE); - rm.score = rm.prevScore = -VALUE_INFINITE; - rm.nodes = 0; - push_back(rm); - } - } - - RootMove* RootMoveList::find(const Move& m, int startIndex) { - - for (size_t i = startIndex; i < size(); i++) - if ((*this)[i].pv[0] == m) - return &(*this)[i]; - - return NULL; + return best; } @@ -1998,7 +1849,7 @@ split_point_start: // At split points actual search starts from here Value v, m = VALUE_NONE; int ply = 0; - assert(pv[0] != MOVE_NONE && pos.is_pseudo_legal(pv[0])); + assert(pv[ply] != MOVE_NONE && pos.is_pseudo_legal(pv[ply])); do { k = pos.get_key(); @@ -2020,9 +1871,9 @@ split_point_start: // At split points actual search starts from here } // namespace -// Thread::idle_loop() is where the thread is parked when it has no work to do. -// The parameter 'sp', if non-NULL, is a pointer to an active SplitPoint object -// for which the thread is the master. +/// Thread::idle_loop() is where the thread is parked when it has no work to do. +/// The parameter 'sp', if non-NULL, is a pointer to an active SplitPoint object +/// for which the thread is the master. void Thread::idle_loop(SplitPoint* sp) { @@ -2036,7 +1887,6 @@ void Thread::idle_loop(SplitPoint* sp) { { assert((!sp && threadID) || Threads.use_sleeping_threads()); - // Slave thread should exit as soon as do_terminate flag raises if (do_terminate) { assert(!sp); @@ -2111,15 +1961,16 @@ void Thread::idle_loop(SplitPoint* sp) { } -// do_timer_event() is called by the timer thread when the timer triggers +/// do_timer_event() is called by the timer thread when the timer triggers. It +/// is used to print debug info and, more important, to detect when we are out of +/// available time and so stop the search. void do_timer_event() { static int lastInfoTime; int e = elapsed_time(); - // Print debug information every one second - if (!lastInfoTime || get_system_time() - lastInfoTime >= 1000) + if (get_system_time() - lastInfoTime >= 1000 || !lastInfoTime) { lastInfoTime = get_system_time(); @@ -2127,7 +1978,6 @@ void do_timer_event() { dbg_print_hit_rate(); } - // Should we stop the search? if (Limits.ponder) return;