X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=092f7d73ed084be2a4a6881890d23a429e072523;hp=677455ec05b0c26bb3722df69f6645a86f0c14d9;hb=c2d42ea8339b49e52a116e488214a14fda09d413;hpb=1d368bbbdc50bbb4e10933c4986abc07a08010fd diff --git a/src/search.cpp b/src/search.cpp index 677455ec..4cf8f471 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -17,10 +17,11 @@ along with this program. If not, see . */ +#include #include #include #include -#include +#include #include #include #include @@ -29,144 +30,67 @@ #include "evaluate.h" #include "history.h" #include "misc.h" -#include "move.h" #include "movegen.h" #include "movepick.h" -#include "lock.h" #include "search.h" #include "timeman.h" #include "thread.h" #include "tt.h" #include "ucioption.h" +namespace Search { + + volatile SignalsType Signals; + LimitsType Limits; + std::vector SearchMoves; + Position RootPosition; +} + +using std::string; using std::cout; using std::endl; +using namespace Search; namespace { - // Different node types, used as template parameter - enum NodeType { NonPV, PV }; - - // Set to true to force running with one thread. Used for debugging. + // Set to true to force running with one thread. Used for debugging const bool FakeSplit = false; - // Lookup table to check if a Piece is a slider and its access function - const bool Slidings[18] = { 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 1 }; - inline bool piece_is_slider(Piece p) { return Slidings[p]; } - - // ThreadsManager class is used to handle all the threads related stuff like init, - // starting, parking and, the most important, launching a slave thread at a split - // point. All the access to shared thread data is done through this class. - - class ThreadsManager { - /* As long as the single ThreadsManager object is defined as a global we don't - need to explicitly initialize to zero its data members because variables with - static storage duration are automatically set to zero before enter main() - */ - public: - Thread& operator[](int threadID) { return threads[threadID]; } - void init_threads(); - void exit_threads(); - - int min_split_depth() const { return minimumSplitDepth; } - int active_threads() const { return activeThreads; } - void set_active_threads(int cnt) { activeThreads = cnt; } - - void read_uci_options(); - bool available_thread_exists(int master) const; - bool thread_is_available(int slave, int master) const; - bool cutoff_at_splitpoint(int threadID) const; - void idle_loop(int threadID, SplitPoint* sp); - - template - void split(Position& pos, SearchStack* ss, Value* alpha, const Value beta, Value* bestValue, - Depth depth, Move threatMove, int moveCount, MovePicker* mp, bool pvNode); - private: - Lock mpLock; - Depth minimumSplitDepth; - int maxThreadsPerSplitPoint; - bool useSleepingThreads; - int activeThreads; - volatile bool allThreadsShouldExit; - Thread threads[MAX_THREADS]; - }; - + // Different node types, used as template parameter + 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 two scores, a node count, and a PV (really a refutation - // in the case of moves which fail low). Value pv_score is normally set at - // -VALUE_INFINITE for all non-pv moves, while non_pv_score is computed - // according to the order in which moves are returned by MovePicker. - + // 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(); - RootMove(const RootMove& rm) { *this = rm; } - RootMove& operator=(const RootMove& rm); - - // 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 pv_score, or if it has - // equal pv_score but m1 has the higher non_pv_score. In this way - // we are guaranteed that PV moves are always sorted as first. - bool operator<(const RootMove& m) const { - return pv_score != m.pv_score ? pv_score < m.pv_score - : non_pv_score < m.non_pv_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); - std::string pv_info_to_uci(Position& pos, int depth, int selDepth, - Value alpha, Value beta, int pvIdx); - int64_t nodes; - Value pv_score; - Value non_pv_score; - Move pv[PLY_MAX_PLUS_2]; - }; - - - // RootMoveList struct is just a vector of RootMove objects, - // with an handful of methods above the standard ones. - - struct RootMoveList : public std::vector { - typedef std::vector Base; - - void init(Position& pos, Move searchMoves[]); - void sort() { insertion_sort(begin(), end()); } - void sort_multipv(int n) { insertion_sort(begin(), begin() + n); } - - int bestMoveChanges; + int64_t nodes; + Value score; + Value prevScore; + std::vector pv; }; - // 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; - } - - - /// Adjustments + /// Constants - // Step 6. Razoring + // Lookup table to check if a Piece is a slider and its access function + const bool Slidings[18] = { 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 1 }; + inline bool piece_is_slider(Piece p) { return Slidings[p]; } // Maximum depth for razoring const Depth RazorDepth = 4 * ONE_PLY; @@ -177,203 +101,129 @@ namespace { // Maximum depth for use of dynamic threat detection when null move fails low const Depth ThreatDepth = 5 * ONE_PLY; - // Step 9. Internal iterative deepening - // Minimum depth for use of internal iterative deepening - const Depth IIDDepth[2] = { 8 * ONE_PLY /* non-PV */, 5 * ONE_PLY /* PV */}; + const Depth IIDDepth[] = { 8 * ONE_PLY, 5 * ONE_PLY }; // At Non-PV nodes we do an internal iterative deepening search // when the static evaluation is bigger then beta - IIDMargin. const Value IIDMargin = Value(0x100); - // Step 11. Decide the new search depth - - // Extensions. Configurable UCI options. Array index 0 is used at - // non-PV nodes, index 1 at PV nodes. - Depth CheckExtension[2], PawnPushTo7thExtension[2]; - Depth PassedPawnExtension[2], PawnEndgameExtension[2]; - // Minimum depth for use of singular extension - const Depth SingularExtensionDepth[2] = { 8 * ONE_PLY /* non-PV */, 6 * ONE_PLY /* PV */}; - - // Step 12. Futility pruning + const Depth SingularExtensionDepth[] = { 8 * ONE_PLY, 6 * ONE_PLY }; // Futility margin for quiescence search const Value FutilityMarginQS = Value(0x80); // Futility lookup tables (initialized at startup) and their access functions - Value FutilityMarginsMatrix[16][64]; // [depth][moveNumber] - int FutilityMoveCountArray[32]; // [depth] + Value FutilityMargins[16][64]; // [depth][moveNumber] + int FutilityMoveCounts[32]; // [depth] - inline Value futility_margin(Depth d, int mn) { return d < 7 * ONE_PLY ? FutilityMarginsMatrix[Max(d, 1)][Min(mn, 63)] : 2 * VALUE_INFINITE; } - inline int futility_move_count(Depth d) { return d < 16 * ONE_PLY ? FutilityMoveCountArray[d] : 512; } + inline Value futility_margin(Depth d, int mn) { - // Step 14. Reduced search + return d < 7 * ONE_PLY ? FutilityMargins[std::max(int(d), 1)][std::min(mn, 63)] + : 2 * VALUE_INFINITE; + } + + inline int futility_move_count(Depth d) { + + return d < 16 * ONE_PLY ? FutilityMoveCounts[d] : MAX_MOVES; + } // Reduction lookup tables (initialized at startup) and their access function - int8_t ReductionMatrix[2][64][64]; // [pv][depth][moveNumber] + int8_t Reductions[2][64][64]; // [pv][depth][moveNumber] - template - inline Depth reduction(Depth d, int mn) { return (Depth) ReductionMatrix[PV][Min(d / ONE_PLY, 63)][Min(mn, 63)]; } + template inline Depth reduction(Depth d, int mn) { + + 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 - // Book - Book OpeningBook; - - // Root move list - RootMoveList Rml; - - // MultiPV mode - int MultiPV, UCIMultiPV; - - // Time management variables - bool StopOnPonderhit, FirstRootMove, StopRequest, QuitRequest, AspirationFailLow; + std::vector RootMoves; + size_t MultiPV, UCIMultiPV, PVIdx; TimeManager TimeMgr; - SearchLimits Limits; - - // Log file - bool UseLogFile; - std::ofstream LogFile; - - // Skill level adjustment + int BestMoveChanges; int SkillLevel; - bool SkillLevelEnabled; - RKISS RK; - - // Multi-threads manager - ThreadsManager ThreadsMgr; - - // 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. - bool SendSearchedNodes; - int NodesSincePoll; - int NodesBetweenPolls = 30000; - - // History table + bool SkillLevelEnabled, Chess960; History H; /// Local functions - Move id_loop(Position& pos, Move searchMoves[], Move* ponderMove); - - template - Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth); + template + Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth); - template - Value qsearch(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth); - - template - inline Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth) { - - return depth < ONE_PLY ? qsearch(pos, ss, alpha, beta, DEPTH_ZERO) - : search(pos, ss, alpha, beta, depth); - } - - template - Depth extension(const Position& pos, Move m, bool captureOrPromotion, bool moveIsCheck, bool* dangerous); + 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); Value value_from_tt(Value v, int ply); - bool ok_to_use_TT(const TTEntry* tte, Depth depth, Value beta, int ply); + 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 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); - std::string value_to_uci(Value v); - std::string speed_to_uci(int64_t nodes); - void poll(const Position& pos); - void wait_for_stop_or_ponderhit(); - -#if !defined(_MSC_VER) - void* init_thread(void* threadID); -#else - DWORD WINAPI init_thread(LPVOID threadID); -#endif - - - // MovePickerExt is an extended MovePicker class used to choose at compile time - // the proper move source according to the type of node. - template struct MovePickerExt; - - // In Root nodes use RootMoveList as source. Score and sort the root moves - // before to search them. - template<> struct MovePickerExt : public MovePicker { - - MovePickerExt(const Position& p, Move ttm, Depth d, const History& h, SearchStack* ss, Value b) - : MovePicker(p, ttm, d, h, ss, b), firstCall(true) { - Move move; - Value score = VALUE_ZERO; - - // Score root moves using standard ordering used in main search, the moves - // are scored according to the order in which they are returned by MovePicker. - // This is the second order score that is used to compare the moves when - // the first orders pv_score of both moves are equal. - while ((move = MovePicker::get_next_move()) != MOVE_NONE) - for (rm = Rml.begin(); rm != Rml.end(); ++rm) - if (rm->pv[0] == move) - { - rm->non_pv_score = score--; - break; - } - - Rml.sort(); - rm = Rml.begin(); - } - - Move get_next_move() { - - if (!firstCall) - ++rm; - else - firstCall = false; - - return rm != Rml.end() ? rm->pv[0] : MOVE_NONE; - } - - RootMoveList::iterator rm; - bool firstCall; + Move do_skill_level(); + int elapsed_time(bool reset = false); + string score_to_uci(Value v, Value alpha = -VALUE_INFINITE, Value beta = VALUE_INFINITE); + 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) + : MovePicker(p, ttm, d, h, ss, b) {} }; - // In SpNodes use split point's shared MovePicker object as move source - template<> struct MovePickerExt : public MovePicker { + // In case of a SpNode we use split point's shared MovePicker object as moves source + template<> struct MovePickerExt : public MovePicker { - MovePickerExt(const Position& p, Move ttm, Depth d, const History& h, SearchStack* ss, Value b) + MovePickerExt(const Position& p, Move ttm, Depth d, const History& h, Stack* ss, Value b) : MovePicker(p, ttm, d, h, ss, b), mp(ss->sp->mp) {} - Move get_next_move() { return mp->get_next_move(); } - - RootMoveList::iterator rm; // Dummy, needed to compile + Move next_move() { return mp->next_move(); } MovePicker* mp; }; - // Default case, create and use a MovePicker object as source - template<> struct MovePickerExt : public MovePicker { + // 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) { - MovePickerExt(const Position& p, Move ttm, Depth d, const History& h, SearchStack* ss, Value b) - : MovePicker(p, ttm, d, h, ss, b) {} + // Test for a pawn pushed to 7th or a passed pawn move + if (type_of(pos.piece_on(move_from(m))) == PAWN) + { + Color c = pos.side_to_move(); + if ( relative_rank(c, move_to(m)) == RANK_7 + || pos.pawn_is_passed(c, move_to(m))) + return true; + } - RootMoveList::iterator rm; // Dummy, needed to compile - }; + // Test for a capture that triggers a pawn endgame + if ( captureOrPromotion + && type_of(pos.piece_on(move_to(m))) != PAWN + && ( pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK) + - PieceValueMidgame[pos.piece_on(move_to(m))] == VALUE_ZERO) + && !is_special(m)) + return true; + + return false; + } } // namespace -/// init_threads() is called during startup. It initializes various lookup tables -/// and creates and launches search threads. +/// Search::init() is called during startup to initialize various lookup tables -void init_threads() { +void Search::init() { int d; // depth (ONE_PLY == 2) int hd; // half depth (ONE_PLY == 1) @@ -384,193 +234,160 @@ void init_threads() { { double pvRed = log(double(hd)) * log(double(mc)) / 3.0; double nonPVRed = 0.33 + log(double(hd)) * log(double(mc)) / 2.25; - ReductionMatrix[PV][hd][mc] = (int8_t) ( pvRed >= 1.0 ? floor( pvRed * int(ONE_PLY)) : 0); - ReductionMatrix[NonPV][hd][mc] = (int8_t) (nonPVRed >= 1.0 ? floor(nonPVRed * int(ONE_PLY)) : 0); + Reductions[1][hd][mc] = (int8_t) ( pvRed >= 1.0 ? floor( pvRed * int(ONE_PLY)) : 0); + Reductions[0][hd][mc] = (int8_t) (nonPVRed >= 1.0 ? floor(nonPVRed * int(ONE_PLY)) : 0); } // Init futility margins array for (d = 1; d < 16; d++) for (mc = 0; mc < 64; mc++) - FutilityMarginsMatrix[d][mc] = Value(112 * int(log(double(d * d) / 2) / log(2.0) + 1.001) - 8 * mc + 45); + FutilityMargins[d][mc] = Value(112 * int(log(double(d * d) / 2) / log(2.0) + 1.001) - 8 * mc + 45); // Init futility move count array for (d = 0; d < 32; d++) - FutilityMoveCountArray[d] = int(3.001 + 0.25 * pow(d, 2.0)); - - // Create and startup threads - ThreadsMgr.init_threads(); + FutilityMoveCounts[d] = int(3.001 + 0.25 * pow(d, 2.0)); } -/// exit_threads() is a trampoline to access ThreadsMgr from outside of current file -void exit_threads() { ThreadsMgr.exit_threads(); } +/// 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) { -/// perft() is our utility to verify move generation. All the legal moves up to -/// given depth are generated and counted and the sum returned. - -int64_t perft(Position& pos, Depth depth) { - - MoveStack mlist[MOVES_MAX]; StateInfo st; - Move m; int64_t sum = 0; - // Generate all legal moves - MoveStack* last = generate(pos, mlist); + 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 int(last - mlist); + return ml.size(); - // Loop through all legal moves CheckInfo ci(pos); - for (MoveStack* cur = mlist; cur != last; cur++) + for ( ; !ml.end(); ++ml) { - m = cur->move; - pos.do_move(m, st, ci, pos.move_is_check(m, ci)); + pos.do_move(ml.move(), st, ci, pos.move_gives_check(ml.move(), ci)); sum += perft(pos, depth - ONE_PLY); - pos.undo_move(m); + pos.undo_move(ml.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 global -/// variables, and calls id_loop(). It returns false when a "quit" command is -/// received during the search. +/// 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. -bool think(Position& pos, const SearchLimits& limits, Move searchMoves[]) { +void Search::think() { - // Initialize global search-related variables - StopOnPonderhit = StopRequest = QuitRequest = AspirationFailLow = SendSearchedNodes = false; - NodesSincePoll = 0; - current_search_time(get_system_time()); - Limits = limits; - TimeMgr.init(Limits, pos.startpos_ply_counter()); + static Book book; // Defined static to initialize the PRNG only once - // 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; - - // Look for a book move, only during games, not tests - if (Limits.useTimeManagement() && Options["OwnBook"].value()) + Position& pos = RootPosition; + 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())); + + if (Options["OwnBook"].value()) { - if (Options["Book File"].value() != OpeningBook.name()) - OpeningBook.open(Options["Book File"].value()); + if (Options["Book File"].value() != book.name()) + book.open(Options["Book File"].value()); - Move bookMove = OpeningBook.get_move(pos, Options["Best Book Move"].value()); - if (bookMove != MOVE_NONE) - { - if (Limits.ponder) - wait_for_stop_or_ponderhit(); + Move bookMove = book.probe(pos, Options["Best Book Move"].value()); - cout << "bestmove " << bookMove << endl; - return !QuitRequest; + if ( bookMove != MOVE_NONE + && count(RootMoves.begin(), RootMoves.end(), bookMove)) + { + std::swap(RootMoves[0], *find(RootMoves.begin(), RootMoves.end(), bookMove)); + goto finish; } } - // Read UCI options - CheckExtension[1] = Options["Check Extension (PV nodes)"].value(); - CheckExtension[0] = Options["Check Extension (non-PV nodes)"].value(); - PawnPushTo7thExtension[1] = Options["Pawn Push to 7th Extension (PV nodes)"].value(); - PawnPushTo7thExtension[0] = Options["Pawn Push to 7th Extension (non-PV nodes)"].value(); - PassedPawnExtension[1] = Options["Passed Pawn Extension (PV nodes)"].value(); - PassedPawnExtension[0] = Options["Passed Pawn Extension (non-PV nodes)"].value(); - PawnEndgameExtension[1] = Options["Pawn Endgame Extension (PV nodes)"].value(); - PawnEndgameExtension[0] = Options["Pawn Endgame Extension (non-PV nodes)"].value(); - UCIMultiPV = Options["MultiPV"].value(); - SkillLevel = Options["Skill level"].value(); - UseLogFile = Options["Use Search Log"].value(); - + // Read UCI options: GUI could change UCI parameters during the game read_evaluation_uci_options(pos.side_to_move()); + Threads.read_uci_options(); + TT.set_size(Options["Hash"].value()); if (Options["Clear Hash"].value()) { Options["Clear Hash"].set_value("false"); TT.clear(); } - TT.set_size(Options["Hash"].value()); + + 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); - - // Set the number of active threads - ThreadsMgr.read_uci_options(); - init_eval(ThreadsMgr.active_threads()); + MultiPV = (SkillLevelEnabled ? std::max(UCIMultiPV, (size_t)4) : UCIMultiPV); - // Wake up needed threads and reset maxPly counter - for (int i = 0; i < ThreadsMgr.active_threads(); i++) + if (Options["Use Search Log"].value()) { - ThreadsMgr[i].wake_up(); - ThreadsMgr[i].maxPly = 0; + Log log(Options["Search Log Filename"].value()); + log << "\nSearching: " << pos.to_fen() + << "\ninfinite: " << Limits.infinite + << " ponder: " << Limits.ponder + << " time: " << Limits.time + << " increment: " << Limits.increment + << " moves to go: " << Limits.movesToGo + << endl; } - // Write to log file and keep it open to be accessed during the search - if (UseLogFile) + for (int i = 0; i < Threads.size(); i++) { - std::string name = Options["Search Log Filename"].value(); - LogFile.open(name.c_str(), std::ios::out | std::ios::app); - - LogFile << "\nSearching: " << pos.to_fen() - << "\ninfinite: " << Limits.infinite - << " ponder: " << Limits.ponder - << " time: " << Limits.time - << " increment: " << Limits.increment - << " moves to go: " << Limits.movesToGo - << endl; + Threads[i].maxPly = 0; + Threads[i].wake_up(); } - // We're ready to start thinking. Call the iterative deepening loop function - Move ponderMove = MOVE_NONE; - Move bestMove = id_loop(pos, searchMoves, &ponderMove); + // Set best timer interval to avoid lagging under time pressure. Timer is + // used to check for remaining available thinking time. + 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 searching. Call the iterative deepening loop function + id_loop(pos); - cout << "info" << speed_to_uci(pos.nodes_searched()) << endl; + // Stop timer and send all the slaves to sleep, if not already sleeping + Threads.set_timer(0); + Threads.set_size(1); - // Write final search statistics and close log file - if (UseLogFile) + if (Options["Use Search Log"].value()) { - int t = current_search_time(); + int e = elapsed_time(); - LogFile << "Nodes: " << pos.nodes_searched() - << "\nNodes/second: " << (t > 0 ? pos.nodes_searched() * 1000 / t : 0) - << "\nBest move: " << move_to_san(pos, bestMove); + 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, RootMoves[0].pv[0]); StateInfo st; - pos.do_move(bestMove, st); - LogFile << "\nPonder move: " << move_to_san(pos, ponderMove) << endl; - pos.undo_move(bestMove); // Return from think() with unchanged position - LogFile.close(); + pos.do_move(RootMoves[0].pv[0], st); + log << "\nPonder move: " << move_to_san(pos, RootMoves[0].pv[1]) << endl; + pos.undo_move(RootMoves[0].pv[0]); } - // This makes all the threads to go to sleep - ThreadsMgr.set_active_threads(1); +finish: - // 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; - - // 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; - - return !QuitRequest; + // Best move could be MOVE_NONE when searching on a stalemate position + cout << "bestmove " << move_to_uci(RootMoves[0].pv[0], Chess960) + << " ponder " << move_to_uci(RootMoves[0].pv[1], Chess960) << endl; } @@ -580,176 +397,180 @@ 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) { - - SearchStack ss[PLY_MAX_PLUS_2]; - Value bestValues[PLY_MAX_PLUS_2]; - int bestMoveChanges[PLY_MAX_PLUS_2]; - int depth, selDepth, aspirationDelta; - Value value, alpha, beta; - Move bestMove, easyMove, skillBest, skillPonder; - - // Initialize stuff before a new search - memset(ss, 0, 4 * sizeof(SearchStack)); - TT.new_search(); - H.clear(); - *ponderMove = bestMove = easyMove = skillBest = skillPonder = MOVE_NONE; - depth = aspirationDelta = 0; - 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); - - // Handle special case of searching on a mate/stalemate position - if (Rml.size() == 0) - { - cout << "info depth 0 score " - << value_to_uci(pos.is_check() ? -VALUE_MATE : VALUE_DRAW) - << endl; + void id_loop(Position& pos) { - return MOVE_NONE; - } - - // Iterative deepening loop - while (++depth <= PLY_MAX && (!Limits.maxDepth || depth <= Limits.maxDepth) && !StopRequest) - { - Rml.bestMoveChanges = 0; - cout << set960(pos.is_chess960()) << "info depth " << depth << endl; + Stack ss[PLY_MAX_PLUS_2]; + int depth, prevBestMoveChanges; + Value bestValue, alpha, beta, delta; + bool bestMoveNeverChanged = true; + Move skillBest = MOVE_NONE; - // Calculate dynamic aspiration window based on previous iterations - if (MultiPV == 1 && depth >= 5 && abs(bestValues[depth - 1]) < VALUE_KNOWN_WIN) - { - 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 = (aspirationDelta + 7) / 8 * 8; // Round to match grainSize - - alpha = Max(bestValues[depth - 1] - aspirationDelta, -VALUE_INFINITE); - beta = Min(bestValues[depth - 1] + aspirationDelta, VALUE_INFINITE); - } + memset(ss, 0, 4 * sizeof(Stack)); + depth = BestMoveChanges = 0; + bestValue = delta = -VALUE_INFINITE; + ss->currentMove = MOVE_NULL; // Hack to skip update gains - // Start with a small aspiration window and, in case of fail high/low, - // research with bigger window until not failing high/low anymore. - do { - // Search starting from ss+1 to allow calling update_gains() - value = search(pos, ss+1, alpha, beta, depth * ONE_PLY); + // Handle the special case of a mate/stalemate position + if (RootMoves.empty()) + { + cout << "info depth 0" + << score_to_uci(pos.in_check() ? -VALUE_MATE : VALUE_DRAW) << endl; - // Write PV back to transposition table in case the relevant entries - // have been overwritten during the search. - for (int i = 0; i < Min(MultiPV, (int)Rml.size()); i++) - Rml[i].insert_pv_in_tt(pos); + RootMoves.push_back(MOVE_NONE); + return; + } - // Value cannot be trusted. Break out immediately! - if (StopRequest) - break; + // Iterative deepening loop until requested to stop or target depth reached + while (!Signals.stop && ++depth <= PLY_MAX && (!Limits.maxDepth || depth <= Limits.maxDepth)) + { + // 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; - assert(value >= alpha); + prevBestMoveChanges = BestMoveChanges; + BestMoveChanges = 0; - // In case of failing high/low increase aspiration window and research, - // otherwise exit the fail high/low loop. - if (value >= beta) + // MultiPV loop. We perform a full root search for each PV line + for (PVIdx = 0; PVIdx < std::min(MultiPV, RootMoves.size()); PVIdx++) + { + // Set aspiration window default width + if (depth >= 5 && abs(RootMoves[PVIdx].prevScore) < VALUE_KNOWN_WIN) { - beta = Min(beta + aspirationDelta, VALUE_INFINITE); - aspirationDelta += aspirationDelta / 2; + delta = Value(16); + alpha = RootMoves[PVIdx].prevScore - delta; + beta = RootMoves[PVIdx].prevScore + delta; } - else if (value <= alpha) + else { - AspirationFailLow = true; - StopOnPonderhit = false; - - alpha = Max(alpha - aspirationDelta, -VALUE_INFINITE); - aspirationDelta += aspirationDelta / 2; + alpha = -VALUE_INFINITE; + beta = VALUE_INFINITE; } - else - break; - } while (abs(value) < VALUE_KNOWN_WIN); + // Start with a small aspiration window and, in case of fail high/low, + // 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. + 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 + // and eventually the new best one are set to -VALUE_INFINITE and + // 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(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 (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 <= PVIdx; i++) + RootMoves[i].insert_pv_in_tt(pos); + + // 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; - // Collect info about search result - bestMove = Rml[0].pv[0]; - *ponderMove = Rml[0].pv[1]; - bestValues[depth] = value; - bestMoveChanges[depth] = Rml.bestMoveChanges; + // 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. + if ((bestValue > alpha && bestValue < beta) || elapsed_time() > 2000) + 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 += delta; + delta += delta / 2; + } + else if (bestValue <= alpha) + { + Signals.failedLowAtRoot = true; + Signals.stopOnPonderhit = false; + + alpha -= delta; + delta += delta / 2; + } + else + break; - // Do we need to pick now the best and the ponder moves ? - if (SkillLevelEnabled && depth == 1 + SkillLevel) - do_skill_level(&skillBest, &skillPonder); + assert(alpha >= -VALUE_INFINITE && beta <= VALUE_INFINITE); - // Retrieve max searched depth among threads - selDepth = 0; - for (int i = 0; i < ThreadsMgr.active_threads(); i++) - if (ThreadsMgr[i].maxPly > selDepth) - selDepth = ThreadsMgr[i].maxPly; + } while (abs(bestValue) < VALUE_KNOWN_WIN); + } - // Send PV line to GUI and to log file - for (int i = 0; i < Min(UCIMultiPV, (int)Rml.size()); i++) - cout << Rml[i].pv_info_to_uci(pos, depth, selDepth, alpha, beta, i) << endl; + // Skills: Do we need to pick now the best move ? + if (SkillLevelEnabled && depth == 1 + SkillLevel) + skillBest = do_skill_level(); - if (UseLogFile) - LogFile << pretty_pv(pos, depth, value, current_search_time(), Rml[0].pv) << endl; + if (Options["Use Search Log"].value()) + pv_info_to_log(pos, depth, bestValue, elapsed_time(), &RootMoves[0].pv[0]); - // Init easyMove after first iteration or drop if differs from the best move - if (depth == 1 && (Rml.size() == 1 || Rml[0].pv_score > Rml[1].pv_score + EasyMoveMargin)) - easyMove = bestMove; - else if (bestMove != easyMove) - easyMove = MOVE_NONE; + // Filter out startup noise when monitoring best move stability + if (depth > 2 && BestMoveChanges) + bestMoveNeverChanged = false; - if (Limits.useTimeManagement() && !StopRequest) + // Do we have time for the next iteration? Can we stop searching now? + if (!Signals.stop && !Signals.stopOnPonderhit && Limits.useTimeManagement()) { - // Time to stop? - bool noMoreTime = false; - - // Stop search early when the last two iterations returned a mate score - if ( depth >= 5 - && abs(bestValues[depth]) >= abs(VALUE_MATE) - 100 - && abs(bestValues[depth - 1]) >= abs(VALUE_MATE) - 100) - noMoreTime = true; - - // Stop search early if one move seems to be much better than the - // others or if there is only a single legal move. In this latter - // case we search up to Iteration 8 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))) - noMoreTime = true; - - // Add some extra time if the best move has changed during the last two iterations - if (depth > 4 && depth < 50) - TimeMgr.pv_instability(bestMoveChanges[depth], bestMoveChanges[depth-1]); + bool stop = false; // Local variable, not the volatile Signals.stop - // Stop search if most of MaxSearchTime is consumed at the end of the - // iteration. We probably don't have enough time to search the first - // move at the next iteration anyway. - if (current_search_time() > (TimeMgr.available_time() * 80) / 128) - noMoreTime = true; + // Take in account some extra time if the best move has changed + if (depth > 4 && depth < 50) + 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. + if (elapsed_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_time() > (TimeMgr.available_time() * 40) / 100)) + { + Value rBeta = bestValue - EasyMoveMargin; + (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; + (ss+1)->excludedMove = MOVE_NONE; + + if (v < rBeta) + stop = true; + } - if (noMoreTime) + if (stop) { + // If we are allowed to ponder do not stop the search now but + // keep pondering until GUI sends "ponderhit" or "stop". if (Limits.ponder) - StopOnPonderhit = true; + Signals.stopOnPonderhit = true; else - break; + Signals.stop = true; } } } - // When using skills fake 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; } @@ -760,15 +581,19 @@ namespace { // all this work again. We also don't need to store anything to the hash table // here: This is taken care of after we return from the split point. - template - Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth) { + template + Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth) { + + const bool PvNode = (NT == PV || NT == Root || NT == SplitPointPV || NT == SplitPointRoot); + const bool SpNode = (NT == SplitPointPV || NT == SplitPointNonPV || NT == SplitPointRoot); + const bool RootNode = (NT == Root || NT == SplitPointRoot); assert(alpha >= -VALUE_INFINITE && alpha <= VALUE_INFINITE); assert(beta > alpha && beta <= VALUE_INFINITE); assert(PvNode || alpha == beta - 1); - assert(pos.thread() >= 0 && pos.thread() < ThreadsMgr.active_threads()); + assert(pos.thread() >= 0 && pos.thread() < Threads.size()); - Move movesSearched[MOVES_MAX]; + Move movesSearched[MAX_MOVES]; int64_t nodes; StateInfo st; const TTEntry *tte; @@ -777,22 +602,30 @@ namespace { Depth ext, newDepth; ValueType vt; Value bestValue, value, oldAlpha; - Value refinedValue, nullValue, futilityBase, futilityValueScaled; // Non-PV specific - bool isPvMove, isCheck, singularExtensionNode, moveIsCheck, captureOrPromotion, dangerous, isBadCap; + Value refinedValue, nullValue, futilityBase, futilityValue; + bool isPvMove, inCheck, singularExtensionNode, givesCheck; + bool captureOrPromotion, dangerous, doFullDepthSearch; int moveCount = 0, playedMoveCount = 0; - int threadID = pos.thread(); + Thread& thread = Threads[pos.thread()]; SplitPoint* sp = NULL; refinedValue = bestValue = value = -VALUE_INFINITE; oldAlpha = alpha; - isCheck = pos.is_check(); + inCheck = pos.in_check(); ss->ply = (ss-1)->ply + 1; // Used to send selDepth info to GUI - if (PvNode && ThreadsMgr[threadID].maxPly < ss->ply) - ThreadsMgr[threadID].maxPly = ss->ply; + if (PvNode && thread.maxPly < ss->ply) + thread.maxPly = ss->ply; - if (SpNode) + // Step 1. Initialize node + if (!SpNode) + { + ss->currentMove = ss->bestMove = threatMove = (ss+1)->excludedMove = MOVE_NONE; + (ss+1)->skipNullMove = false; (ss+1)->reduction = DEPTH_ZERO; + (ss+2)->killers[0] = (ss+2)->killers[1] = MOVE_NONE; + } + else { sp = ss->sp; tte = NULL; @@ -800,57 +633,54 @@ namespace { threatMove = sp->threatMove; goto split_point_start; } - else if (Root) - bestValue = alpha; - - // Step 1. Initialize node and poll. Polling can abort search - ss->currentMove = ss->bestMove = threatMove = (ss+1)->excludedMove = MOVE_NONE; - (ss+1)->skipNullMove = false; (ss+1)->reduction = DEPTH_ZERO; - (ss+2)->killers[0] = (ss+2)->killers[1] = (ss+2)->mateKiller = MOVE_NONE; - - if (threadID == 0 && ++NodesSincePoll > NodesBetweenPolls) - { - NodesSincePoll = 0; - poll(pos); - } // Step 2. Check for aborted search and immediate draw - if (( StopRequest - || ThreadsMgr.cutoff_at_splitpoint(threadID) - || pos.is_draw() - || ss->ply > PLY_MAX) && !Root) + if (( Signals.stop + || pos.is_draw() + || ss->ply > PLY_MAX) && !RootNode) return VALUE_DRAW; // Step 3. Mate distance pruning - alpha = Max(value_mated_in(ss->ply), alpha); - beta = Min(value_mate_in(ss->ply+1), beta); - if (alpha >= beta) - return alpha; + if (!RootNode) + { + alpha = std::max(value_mated_in(ss->ply), alpha); + beta = std::min(value_mate_in(ss->ply+1), beta); + if (alpha >= beta) + return alpha; + } // Step 4. Transposition table lookup // We don't want the score of a partial search to overwrite a previous full search // TT value, so we use a different position key in case of an excluded move. excludedMove = ss->excludedMove; - posKey = excludedMove ? pos.get_exclusion_key() : pos.get_key(); - - tte = TT.retrieve(posKey); - ttMove = tte ? tte->move() : MOVE_NONE; + posKey = excludedMove ? pos.exclusion_key() : pos.key(); + tte = TT.probe(posKey); + 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 - // smooth experience in analysis mode. - if ( !Root - && tte - && (PvNode ? tte->depth() >= depth && tte->type() == VALUE_TYPE_EXACT - : ok_to_use_TT(tte, depth, beta, ss->ply))) + // smooth experience in analysis mode. We don't probe at Root nodes otherwise + // we should also update RootMoveList to avoid bogus output. + if (!RootNode && tte && (PvNode ? tte->depth() >= depth && tte->type() == VALUE_TYPE_EXACT + : can_return_tt(tte, depth, beta, ss->ply))) { TT.refresh(tte); - ss->bestMove = ttMove; // Can be MOVE_NONE - return value_from_tt(tte->value(), ss->ply); + ss->bestMove = move = ttMove; // Can be MOVE_NONE + value = value_from_tt(tte->value(), ss->ply); + + if ( value >= beta + && move + && !pos.is_capture_or_promotion(move) + && move != ss->killers[0]) + { + ss->killers[1] = ss->killers[0]; + ss->killers[0] = move; + } + return value; } // Step 5. Evaluate the position statically and update parent's gain statistics - if (isCheck) + if (inCheck) ss->eval = ss->evalMargin = VALUE_NONE; else if (tte) { @@ -866,13 +696,22 @@ 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 && depth < RazorDepth - && !isCheck + && !inCheck && refinedValue + razor_margin(depth) < beta && ttMove == MOVE_NONE && abs(beta) < VALUE_MATE_IN_PLY_MAX @@ -892,7 +731,7 @@ namespace { if ( !PvNode && !ss->skipNullMove && depth < RazorDepth - && !isCheck + && !inCheck && refinedValue - futility_margin(depth, 0) >= beta && abs(beta) < VALUE_MATE_IN_PLY_MAX && pos.non_pawn_material(pos.side_to_move())) @@ -902,7 +741,7 @@ namespace { if ( !PvNode && !ss->skipNullMove && depth > ONE_PLY - && !isCheck + && !inCheck && refinedValue >= beta && abs(beta) < VALUE_MATE_IN_PLY_MAX && pos.non_pawn_material(pos.side_to_move())) @@ -916,11 +755,12 @@ namespace { if (refinedValue - PawnValueMidgame > beta) R++; - pos.do_null_move(st); + pos.do_null_move(st); (ss+1)->skipNullMove = true; - nullValue = -search(pos, ss+1, -beta, -alpha, depth-R*ONE_PLY); + nullValue = depth-R*ONE_PLY < ONE_PLY ? -qsearch(pos, ss+1, -beta, -alpha, DEPTH_ZERO) + : - search(pos, ss+1, -beta, -alpha, depth-R*ONE_PLY); (ss+1)->skipNullMove = false; - pos.undo_null_move(); + pos.do_null_move(st); if (nullValue >= beta) { @@ -957,88 +797,125 @@ namespace { } } - // Step 9. Internal iterative deepening + // Step 9. ProbCut (is omitted in PV nodes) + // If we have a very good capture (i.e. SEE > seeValues[captured_piece_type]) + // and a reduced search returns a value much above beta, we can (almost) safely + // prune the previous move. + if ( !PvNode + && depth >= RazorDepth + ONE_PLY + && !inCheck + && !ss->skipNullMove + && excludedMove == MOVE_NONE + && abs(beta) < VALUE_MATE_IN_PLY_MAX) + { + Value rbeta = beta + 200; + Depth rdepth = depth - ONE_PLY - 3 * ONE_PLY; + + assert(rdepth >= ONE_PLY); + + MovePicker mp(pos, ttMove, H, pos.captured_piece_type()); + CheckInfo ci(pos); + + while ((move = mp.next_move()) != MOVE_NONE) + if (pos.pl_move_is_legal(move, ci.pinned)) + { + pos.do_move(move, st, ci, pos.move_gives_check(move, ci)); + value = -search(pos, ss+1, -rbeta, -rbeta+1, rdepth); + pos.undo_move(move); + if (value >= rbeta) + return value; + } + } + + // Step 10. Internal iterative deepening if ( depth >= IIDDepth[PvNode] && ttMove == MOVE_NONE - && (PvNode || (!isCheck && ss->eval + IIDMargin >= beta))) + && (PvNode || (!inCheck && ss->eval + IIDMargin >= beta))) { Depth d = (PvNode ? depth - 2 * ONE_PLY : depth / 2); ss->skipNullMove = true; - search(pos, ss, alpha, beta, d); + search(pos, ss, alpha, beta, d); ss->skipNullMove = false; - ttMove = ss->bestMove; - tte = TT.retrieve(posKey); + tte = TT.probe(posKey); + ttMove = tte ? tte->move() : MOVE_NONE; } 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)); + MovePickerExt mp(pos, ttMove, depth, H, ss, PvNode ? -VALUE_INFINITE : beta); CheckInfo ci(pos); ss->bestMove = MOVE_NONE; futilityBase = ss->eval + ss->evalMargin; - singularExtensionNode = !Root + singularExtensionNode = !RootNode && !SpNode && depth >= SingularExtensionDepth[PvNode] - && tte - && tte->move() - && !excludedMove // Do not allow recursive singular extension search + && ttMove != MOVE_NONE + && !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 10. Loop through moves - // Loop through all legal moves until no moves remain or a beta cutoff occurs + // Step 11. Loop through moves + // Loop through all pseudo-legal moves until no moves remain or a beta cutoff occurs while ( bestValue < beta - && (move = mp.get_next_move()) != MOVE_NONE - && !ThreadsMgr.cutoff_at_splitpoint(threadID)) + && (move = mp.next_move()) != MOVE_NONE + && !thread.cutoff_occurred()) { - assert(move_is_ok(move)); + assert(is_ok(move)); + + if (move == excludedMove) + continue; + + // 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 && !count(RootMoves.begin() + PVIdx, RootMoves.end(), move)) + continue; + + // At PV and SpNode nodes we want all moves to be legal since the beginning + if ((PvNode || SpNode) && !pos.pl_move_is_legal(move, ci.pinned)) + continue; if (SpNode) { moveCount = ++sp->moveCount; lock_release(&(sp->lock)); } - else if (move == excludedMove) - continue; else moveCount++; - if (Root) + if (RootNode) { - // This is used by time management - FirstRootMove = (moveCount == 1); - - // Save the current node count before the move is searched + Signals.firstRootMove = (moveCount == 1); nodes = pos.nodes_searched(); - // If it's time to send nodes info, do it here where we have the - // correct accumulated node counts searched by each thread. - if (SendSearchedNodes) - { - SendSearchedNodes = false; - cout << "info" << speed_to_uci(pos.nodes_searched()) << endl; - } - - if (current_search_time() > 2000) - cout << "info currmove " << move - << " currmovenumber " << moveCount << endl; + if (pos.thread() == 0 && elapsed_time() > 2000) + cout << "info depth " << depth / ONE_PLY + << " currmove " << move_to_uci(move, Chess960) + << " currmovenumber " << moveCount + PVIdx << endl; } - // At Root and at first iteration do a PV search on all the moves to score root moves - isPvMove = (PvNode && moveCount <= (Root ? depth <= ONE_PLY ? 1000 : MultiPV : 1)); - moveIsCheck = pos.move_is_check(move, ci); - captureOrPromotion = pos.move_is_capture_or_promotion(move); + isPvMove = (PvNode && moveCount <= 1); + captureOrPromotion = pos.is_capture_or_promotion(move); + givesCheck = pos.move_gives_check(move, ci); + dangerous = givesCheck || is_dangerous(pos, move, captureOrPromotion); + ext = DEPTH_ZERO; - // Step 11. Decide the new search depth - ext = extension(pos, move, captureOrPromotion, moveIsCheck, &dangerous); + // Step 12. Extend checks and, in PV nodes, also dangerous moves + if (PvNode && dangerous) + ext = ONE_PLY; + + else if (givesCheck && pos.see_sign(move) >= 0) + ext = PvNode ? ONE_PLY : ONE_PLY / 2; // Singular extension search. If all moves but one fail low on a search of // (alpha-s, beta-s), and just one fails high on (alpha, beta), then that move @@ -1046,8 +923,9 @@ split_point_start: // At split points actual search starts from here // on all the other moves but the ttMove, if result is lower than ttValue minus // a margin then we extend ttMove. if ( singularExtensionNode - && move == tte->move() - && ext < ONE_PLY) + && !ext + && move == ttMove + && pos.pl_move_is_legal(move, ci.pinned)) { Value ttValue = value_from_tt(tte->value(), ss->ply); @@ -1056,31 +934,30 @@ 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; } } // Update current move (this must be done after singular extension search) - ss->currentMove = move; newDepth = depth - ONE_PLY + ext; - // Step 12. Futility pruning (is omitted in PV nodes) + // Step 13. Futility pruning (is omitted in PV nodes) if ( !PvNode && !captureOrPromotion - && !isCheck + && !inCheck && !dangerous && move != ttMove - && !move_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)); @@ -1091,27 +968,20 @@ split_point_start: // At split points actual search starts from here // Value based pruning // We illogically ignore reduction condition depth >= 3*ONE_PLY for predicted depth, // but fixing this made program slightly weaker. - Depth predictedDepth = newDepth - reduction(depth, moveCount); - futilityValueScaled = futilityBase + futility_margin(predictedDepth, moveCount) - + H.gain(pos.piece_on(move_from(move)), move_to(move)); + Depth predictedDepth = newDepth - reduction(depth, moveCount); + futilityValue = futilityBase + futility_margin(predictedDepth, moveCount) + + H.gain(pos.piece_on(move_from(move)), move_to(move)); - if (futilityValueScaled < beta) + if (futilityValue < beta) { if (SpNode) - { lock_grab(&(sp->lock)); - if (futilityValueScaled > sp->bestValue) - sp->bestValue = bestValue = futilityValueScaled; - } - else if (futilityValueScaled > bestValue) - bestValue = futilityValueScaled; 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) @@ -1121,90 +991,64 @@ split_point_start: // At split points actual search starts from here } } - // Bad capture detection. Will be used by prob-cut search - isBadCap = depth >= 3 * ONE_PLY - && depth < 8 * ONE_PLY - && captureOrPromotion - && move != ttMove - && !dangerous - && !move_is_promotion(move) - && abs(alpha) < VALUE_MATE_IN_PLY_MAX - && pos.see_sign(move) < 0; - - // Step 13. Make the move - pos.do_move(move, st, ci, moveIsCheck); + // Check for legality only before to do the move + if (!pos.pl_move_is_legal(move, ci.pinned)) + { + moveCount--; + continue; + } + ss->currentMove = move; if (!SpNode && !captureOrPromotion) movesSearched[playedMoveCount++] = move; - // Step extra. pv search (only in PV nodes) - // The first move in list is the expected PV - if (isPvMove) - { - // Aspiration window is disabled in multi-pv case - if (Root && MultiPV > 1) - alpha = -VALUE_INFINITE; + // Step 14. Make the move + pos.do_move(move, st, ci, givesCheck); - value = -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 14. Reduced depth search - // If the move fails high will be re-searched at full depth. - bool doFullDepthSearch = true; + ss->reduction = reduction(depth, moveCount); + Depth d = newDepth - ss->reduction; alpha = SpNode ? sp->alpha : alpha; - if ( depth >= 3 * ONE_PLY - && !captureOrPromotion - && !dangerous - && !move_is_castle(move) - && ss->killers[0] != move - && ss->killers[1] != move) - { - ss->reduction = reduction(depth, moveCount); - if (ss->reduction) - { - alpha = SpNode ? sp->alpha : alpha; - Depth d = newDepth - ss->reduction; - value = -search(pos, ss+1, -(alpha+1), -alpha, d); - - doFullDepthSearch = (value > alpha); - } - ss->reduction = DEPTH_ZERO; // Restore original reduction - } + value = d < ONE_PLY ? -qsearch(pos, ss+1, -(alpha+1), -alpha, DEPTH_ZERO) + : - search(pos, ss+1, -(alpha+1), -alpha, d); - // Probcut search for bad captures. If a reduced search returns a value - // very below beta then we can (almost) safely prune the bad capture. - if (isBadCap) - { - ss->reduction = 3 * ONE_PLY; - Value rAlpha = alpha - 300; - Depth d = newDepth - ss->reduction; - value = -search(pos, ss+1, -(rAlpha+1), -rAlpha, d); - doFullDepthSearch = (value > rAlpha); - ss->reduction = DEPTH_ZERO; // Restore original reduction - } + doFullDepthSearch = (value > alpha && ss->reduction != DEPTH_ZERO); + ss->reduction = DEPTH_ZERO; + } + else + doFullDepthSearch = !isPvMove; - // Step 15. Full depth search - if (doFullDepthSearch) - { - alpha = SpNode ? sp->alpha : alpha; - value = -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 && (Root || value < beta)) - value = -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); } - // Step 16. Undo move + // 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); assert(value > -VALUE_INFINITE && value < VALUE_INFINITE); - // Step 17. Check for new best move + // Step 18. Check for new best move if (SpNode) { lock_grab(&(sp->lock)); @@ -1212,100 +1056,85 @@ split_point_start: // At split points actual search starts from here alpha = sp->alpha; } - if (value > bestValue && !(SpNode && ThreadsMgr.cutoff_at_splitpoint(threadID))) - { - bestValue = value; - - if (SpNode) - sp->bestValue = value; - - if (!Root && value > alpha) - { - if (PvNode && value < beta) // We want always alpha < beta - { - alpha = value; - - if (SpNode) - sp->alpha = value; - } - else if (SpNode) - sp->betaCutoff = true; - - if (value == value_mate_in(ss->ply + 1)) - ss->mateKiller = move; - - ss->bestMove = move; - - if (SpNode) - sp->ss->bestMove = move; - } - } - - if (Root) + // Finished searching the move. If StopRequest is true, the search + // 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 && !Signals.stop) { - // Finished searching the move. If StopRequest is true, the search - // 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 break out of the loop without updating the best - // move and/or PV. - if (StopRequest) - break; - - // Remember searched nodes counts for this move - mp.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 - ss->bestMove = move; - mp.rm->pv_score = value; - mp.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++; - - Rml.sort_multipv(moveCount); - - // Update alpha. In multi-pv we don't use aspiration window, so - // set alpha equal to minimum score among the PV lines. - if (MultiPV > 1) - alpha = Rml[Min(moveCount, MultiPV) - 1].pv_score; // FIXME why moveCount? - else if (value > alpha) - alpha = value; + BestMoveChanges++; } else - mp.rm->pv_score = -VALUE_INFINITE; + // 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; - } // Root + } + + if (value > bestValue) + { + bestValue = value; + ss->bestMove = move; + + if ( PvNode + && value > alpha + && value < beta) // We want always alpha < beta + alpha = value; - // Step 18. Check for split - if ( !Root - && !SpNode - && depth >= ThreadsMgr.min_split_depth() - && ThreadsMgr.active_threads() > 1 + if (SpNode && !thread.cutoff_occurred()) + { + sp->bestValue = value; + sp->ss->bestMove = move; + sp->alpha = alpha; + sp->is_betaCutoff = (value >= beta); + } + } + + // Step 19. Check for split + if ( !SpNode + && depth >= Threads.min_split_depth() && bestValue < beta - && ThreadsMgr.available_thread_exists(threadID) - && !StopRequest - && !ThreadsMgr.cutoff_at_splitpoint(threadID)) - ThreadsMgr.split(pos, ss, &alpha, beta, &bestValue, depth, - threatMove, moveCount, &mp, PvNode); + && Threads.available_slave_exists(pos.thread()) + && !Signals.stop + && !thread.cutoff_occurred()) + bestValue = Threads.split(pos, ss, alpha, beta, bestValue, depth, + threatMove, moveCount, &mp, NT); } - // Step 19. Check for mate and stalemate - // All legal moves have been searched and if there are - // no legal moves, it must be mate or stalemate. - // If one move was excluded return fail low score. - if (!SpNode && !moveCount) - return excludedMove ? oldAlpha : isCheck ? value_mated_in(ss->ply) : VALUE_DRAW; - - // Step 20. Update tables - // If the search is not aborted, update the transposition table, - // history counters, and killer moves. - if (!SpNode && !StopRequest && !ThreadsMgr.cutoff_at_splitpoint(threadID)) + // Step 20. Check for mate and stalemate + // All legal moves have been searched and if there are no legal moves, it + // must be mate or stalemate. Note that we can have a false positive in + // 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 (!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 + // Update transposition table entry, killers and history + if (!SpNode && !Signals.stop && !thread.cutoff_occurred()) { move = bestValue <= oldAlpha ? MOVE_NONE : ss->bestMove; vt = bestValue <= oldAlpha ? VALUE_TYPE_UPPER @@ -1313,23 +1142,34 @@ 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.move_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); + } } } if (SpNode) { // Here we have the lock still grabbed - sp->slaves[threadID] = 0; + sp->is_slave[pos.thread()] = false; sp->nodes += pos.nodes_searched(); lock_release(&(sp->lock)); } @@ -1339,53 +1179,58 @@ 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). - template - Value qsearch(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth) { + template + Value qsearch(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth) { + const bool PvNode = (NT == PV); + + assert(NT == PV || NT == NonPV); assert(alpha >= -VALUE_INFINITE && alpha <= VALUE_INFINITE); assert(beta >= -VALUE_INFINITE && beta <= VALUE_INFINITE); assert(PvNode || alpha == beta - 1); assert(depth <= 0); - assert(pos.thread() >= 0 && pos.thread() < ThreadsMgr.active_threads()); + assert(pos.thread() >= 0 && pos.thread() < Threads.size()); StateInfo st; Move ttMove, move; Value bestValue, value, evalMargin, futilityValue, futilityBase; - bool isCheck, enoughMaterial, moveIsCheck, evasionPrunable; + bool inCheck, enoughMaterial, givesCheck, evasionPrunable; const TTEntry* tte; Depth ttDepth; + ValueType vt; Value oldAlpha = alpha; ss->bestMove = ss->currentMove = MOVE_NONE; ss->ply = (ss-1)->ply + 1; // Check for an instant draw or maximum ply reached - if (ss->ply > PLY_MAX || pos.is_draw()) + if (pos.is_draw() || ss->ply > PLY_MAX) return VALUE_DRAW; // Decide whether or not to include checks, this fixes also the type of // TT entry depth that we are going to use. Note that in qsearch we use // only two types of depth in TT: DEPTH_QS_CHECKS or DEPTH_QS_NO_CHECKS. - isCheck = pos.is_check(); - ttDepth = (isCheck || depth >= DEPTH_QS_CHECKS ? DEPTH_QS_CHECKS : DEPTH_QS_NO_CHECKS); + inCheck = pos.in_check(); + ttDepth = (inCheck || depth >= DEPTH_QS_CHECKS ? DEPTH_QS_CHECKS : DEPTH_QS_NO_CHECKS); // Transposition table lookup. At PV nodes, we don't use the TT for // pruning, but only for move ordering. - tte = TT.retrieve(pos.get_key()); + tte = TT.probe(pos.key()); ttMove = (tte ? tte->move() : MOVE_NONE); - if (!PvNode && tte && ok_to_use_TT(tte, ttDepth, beta, ss->ply)) + if (!PvNode && tte && can_return_tt(tte, ttDepth, beta, ss->ply)) { ss->bestMove = ttMove; // Can be MOVE_NONE return value_from_tt(tte->value(), ss->ply); } // Evaluate the position statically - if (isCheck) + if (inCheck) { bestValue = futilityBase = -VALUE_INFINITE; ss->eval = evalMargin = VALUE_NONE; @@ -1403,13 +1248,11 @@ split_point_start: // At split points actual search starts from here else ss->eval = bestValue = evaluate(pos, evalMargin); - update_gains(pos, (ss-1)->currentMove, (ss-1)->eval, ss->eval); - // Stand pat. Return immediately if static value is at least beta if (bestValue >= beta) { if (!tte) - TT.store(pos.get_key(), value_to_tt(bestValue, ss->ply), VALUE_TYPE_LOWER, DEPTH_NONE, MOVE_NONE, ss->eval, evalMargin); + TT.store(pos.key(), value_to_tt(bestValue, ss->ply), VALUE_TYPE_LOWER, DEPTH_NONE, MOVE_NONE, ss->eval, evalMargin); return bestValue; } @@ -1417,7 +1260,6 @@ 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; } @@ -1426,34 +1268,35 @@ split_point_start: // At split points actual search starts from here // to search the moves. Because the depth is <= 0 here, only captures, // queen promotions and checks (only if depth >= DEPTH_QS_CHECKS) will // be generated. - MovePicker mp(pos, ttMove, depth, H); + MovePicker mp(pos, ttMove, depth, H, move_to((ss-1)->currentMove)); CheckInfo ci(pos); // Loop through the moves until no moves remain or a beta cutoff occurs - while ( alpha < beta - && (move = mp.get_next_move()) != MOVE_NONE) + while ( bestValue < beta + && (move = mp.next_move()) != MOVE_NONE) { - assert(move_is_ok(move)); + assert(is_ok(move)); - moveIsCheck = pos.move_is_check(move, ci); + givesCheck = pos.move_gives_check(move, ci); // Futility pruning if ( !PvNode - && !isCheck - && !moveIsCheck + && !inCheck + && !givesCheck && move != ttMove && enoughMaterial - && !move_is_promotion(move) - && !pos.move_is_passed_pawn_push(move)) + && !is_promotion(move) + && !pos.is_passed_pawn_push(move)) { futilityValue = futilityBase - + pos.endgame_value_of_piece_on(move_to(move)) - + (move_is_ep(move) ? PawnValueEndgame : VALUE_ZERO); + + PieceValueEndgame[pos.piece_on(move_to(move))] + + (is_enpassant(move) ? PawnValueEndgame : VALUE_ZERO); - if (futilityValue < alpha) + if (futilityValue < beta) { if (futilityValue > bestValue) bestValue = futilityValue; + continue; } @@ -1465,25 +1308,26 @@ split_point_start: // At split points actual search starts from here } // Detect non-capture evasions that are candidate to be pruned - evasionPrunable = isCheck + evasionPrunable = !PvNode + && inCheck && bestValue > VALUE_MATED_IN_PLY_MAX - && !pos.move_is_capture(move) + && !pos.is_capture(move) && !pos.can_castle(pos.side_to_move()); // Don't search moves with negative SEE values if ( !PvNode - && (!isCheck || evasionPrunable) + && (!inCheck || evasionPrunable) && move != ttMove - && !move_is_promotion(move) + && !is_promotion(move) && pos.see_sign(move) < 0) continue; // Don't search useless checks if ( !PvNode - && !isCheck - && moveIsCheck + && !inCheck + && givesCheck && move != ttMove - && !pos.move_is_capture_or_promotion(move) + && !pos.is_capture_or_promotion(move) && ss->eval + PawnValueMidgame / 4 < beta && !check_is_dangerous(pos, move, futilityBase, beta, &bestValue)) { @@ -1493,12 +1337,15 @@ split_point_start: // At split points actual search starts from here continue; } - // Update current move + // Check for legality only before to do the move + if (!pos.pl_move_is_legal(move, ci.pinned)) + continue; + ss->currentMove = move; // Make and search the move - pos.do_move(move, st, ci, moveIsCheck); - value = -qsearch(pos, ss+1, -beta, -alpha, depth-ONE_PLY); + pos.do_move(move, st, ci, givesCheck); + value = -qsearch(pos, ss+1, -beta, -alpha, depth-ONE_PLY); pos.undo_move(move); assert(value > -VALUE_INFINITE && value < VALUE_INFINITE); @@ -1507,22 +1354,26 @@ split_point_start: // At split points actual search starts from here if (value > bestValue) { bestValue = value; - if (value > alpha) - { + ss->bestMove = move; + + if ( PvNode + && value > alpha + && value < beta) // We want always alpha < beta alpha = value; - ss->bestMove = move; - } } } // All legal moves have been searched. A special case: If we're in check // and no legal moves were found, it is checkmate. - if (isCheck && bestValue == -VALUE_INFINITE) + if (inCheck && bestValue == -VALUE_INFINITE) return value_mated_in(ss->ply); // Update transposition table - ValueType vt = (bestValue <= oldAlpha ? VALUE_TYPE_UPPER : bestValue >= beta ? VALUE_TYPE_LOWER : VALUE_TYPE_EXACT); - TT.store(pos.get_key(), value_to_tt(bestValue, ss->ply), vt, ttDepth, ss->bestMove, ss->eval, evalMargin); + move = bestValue <= oldAlpha ? MOVE_NONE : ss->bestMove; + vt = bestValue <= oldAlpha ? VALUE_TYPE_UPPER + : bestValue >= beta ? VALUE_TYPE_LOWER : VALUE_TYPE_EXACT; + + TT.store(pos.key(), value_to_tt(bestValue, ss->ply), vt, ttDepth, move, ss->eval, evalMargin); assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE); @@ -1544,7 +1395,7 @@ split_point_start: // At split points actual search starts from here from = move_from(move); to = move_to(move); - them = opposite_color(pos.side_to_move()); + them = flip(pos.side_to_move()); ksq = pos.king_square(them); kingAtt = pos.attacks_from(ksq); pc = pos.piece_on(from); @@ -1554,23 +1405,23 @@ split_point_start: // At split points actual search starts from here newAtt = pos.attacks_from(pc, to, occ); // Rule 1. Checks which give opponent's king at most one escape square are dangerous - b = kingAtt & ~pos.pieces_of_color(them) & ~newAtt & ~(1ULL << to); + b = kingAtt & ~pos.pieces(them) & ~newAtt & ~(1ULL << to); if (!(b && (b & (b - 1)))) return true; // Rule 2. Queen contact check is very dangerous - if ( type_of_piece(pc) == QUEEN + if ( type_of(pc) == QUEEN && bit_is_set(kingAtt, to)) return true; // Rule 3. Creating new double threats with checks - b = pos.pieces_of_color(them) & newAtt & ~oldAtt & ~(1ULL << ksq); + b = pos.pieces(them) & newAtt & ~oldAtt & ~(1ULL << ksq); while (b) { victimSq = pop_1st_bit(&b); - futilityValue = futilityBase + pos.endgame_value_of_piece_on(victimSq); + futilityValue = futilityBase + PieceValueEndgame[pos.piece_on(victimSq)]; // Note that here we generate illegal "double move"! if ( futilityValue >= beta @@ -1596,10 +1447,11 @@ split_point_start: // At split points actual search starts from here bool connected_moves(const Position& pos, Move m1, Move m2) { Square f1, t1, f2, t2; - Piece p; + Piece p1, p2; + Square ksq; - assert(m1 && move_is_ok(m1)); - assert(m2 && move_is_ok(m2)); + assert(is_ok(m1)); + assert(is_ok(m2)); // Case 1: The moving piece is the same in both moves f2 = move_from(m2); @@ -1614,26 +1466,24 @@ split_point_start: // At split points actual search starts from here return true; // Case 3: Moving through the vacated square - if ( piece_is_slider(pos.piece_on(f2)) + p2 = pos.piece_on(f2); + if ( piece_is_slider(p2) && bit_is_set(squares_between(f2, t2), f1)) return true; // Case 4: The destination square for m2 is defended by the moving piece in m1 - p = pos.piece_on(t1); - if (bit_is_set(pos.attacks_from(p, t1), t2)) + p1 = pos.piece_on(t1); + if (bit_is_set(pos.attacks_from(p1, t1), t2)) return true; // Case 5: Discovered check, checking piece is the piece moved in m1 - if ( piece_is_slider(p) - && bit_is_set(squares_between(t1, pos.king_square(pos.side_to_move())), f2) - && !bit_is_set(squares_between(t1, pos.king_square(pos.side_to_move())), t2)) + ksq = pos.king_square(pos.side_to_move()); + if ( piece_is_slider(p1) + && bit_is_set(squares_between(t1, ksq), f2)) { - // discovered_check_candidates() works also if the Position's side to - // move is the opposite of the checking piece. - Color them = opposite_color(pos.side_to_move()); - Bitboard dcCandidates = pos.discovered_check_candidates(them); - - if (bit_is_set(dcCandidates, f2)) + Bitboard occ = pos.occupied_squares(); + clear_bit(&occ, f2); + if (bit_is_set(pos.attacks_from(p1, t1, occ), ksq)) return true; } return false; @@ -1641,8 +1491,8 @@ split_point_start: // At split points actual search starts from here // value_to_tt() adjusts a mate score from "plies to mate from the root" to - // "plies to mate from the current ply". Non-mate scores are unchanged. - // The function is called before storing a value to the transposition table. + // "plies to mate from the current ply". Non-mate scores are unchanged. The + // function is called before storing a value to the transposition table. Value value_to_tt(Value v, int ply) { @@ -1671,63 +1521,15 @@ split_point_start: // At split points actual search starts from here } - // extension() decides whether a move should be searched with normal depth, - // or with extended depth. Certain classes of moves (checking moves, in - // particular) are searched with bigger depth than ordinary moves and in - // any case are marked as 'dangerous'. Note that also if a move is not - // 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. - template - Depth extension(const Position& pos, Move m, bool captureOrPromotion, - bool moveIsCheck, bool* dangerous) { - - assert(m != MOVE_NONE); - - Depth result = DEPTH_ZERO; - *dangerous = moveIsCheck; - - if (moveIsCheck && pos.see_sign(m) >= 0) - result += CheckExtension[PvNode]; - - if (pos.type_of_piece_on(move_from(m)) == PAWN) - { - Color c = pos.side_to_move(); - if (relative_rank(c, move_to(m)) == RANK_7) - { - result += PawnPushTo7thExtension[PvNode]; - *dangerous = true; - } - if (pos.pawn_is_passed(c, move_to(m))) - { - result += PassedPawnExtension[PvNode]; - *dangerous = true; - } - } - - 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_ZERO) - && !move_is_special(m)) - { - result += PawnEndgameExtension[PvNode]; - *dangerous = true; - } - - return Min(result, ONE_PLY); - } - - // connected_threat() tests whether it is safe to forward prune a move or if // is somehow connected to the threat move returned by null search. bool connected_threat(const Position& pos, Move m, Move threat) { - assert(move_is_ok(m)); - assert(threat && move_is_ok(threat)); - assert(!pos.move_is_check(m)); - assert(!pos.move_is_capture_or_promotion(m)); - assert(!pos.move_is_passed_pawn_push(m)); + assert(is_ok(m)); + assert(is_ok(threat)); + assert(!pos.is_capture_or_promotion(m)); + assert(!pos.is_passed_pawn_push(m)); Square mfrom, mto, tfrom, tto; @@ -1742,9 +1544,9 @@ split_point_start: // At split points actual search starts from here // Case 2: If the threatened piece has value less than or equal to the // value of the threatening piece, don't prune moves which defend it. - if ( pos.move_is_capture(threat) - && ( pos.midgame_value_of_piece_on(tfrom) >= pos.midgame_value_of_piece_on(tto) - || pos.type_of_piece_on(tfrom) == KING) + if ( pos.is_capture(threat) + && ( PieceValueMidgame[pos.piece_on(tfrom)] >= PieceValueMidgame[pos.piece_on(tto)] + || type_of(pos.piece_on(tfrom)) == KING) && pos.move_attacks_square(m, tto)) return true; @@ -1759,24 +1561,24 @@ split_point_start: // At split points actual search starts from here } - // ok_to_use_TT() returns true if a transposition table score - // can be used 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 ok_to_use_TT(const TTEntry* tte, Depth depth, Value beta, int ply) { + bool can_return_tt(const TTEntry* tte, Depth depth, Value beta, int ply) { 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)); } - // 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) { @@ -1792,623 +1594,214 @@ 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); - } - } - - - // 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 - && !move_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_time(bool reset) { static int searchStartTime; - if (set) - searchStartTime = set; + if (reset) + searchStartTime = system_time(); - return get_system_time() - searchStartTime; + return system_time() - searchStartTime; } - // value_to_uci() converts a value to a string suitable for use with the UCI + // score_to_uci() converts a value to a string suitable for use with the UCI // protocol specifications: // // cp The score from the engine's point of view in centipawns. // mate Mate in y moves, not plies. If the engine is getting mated // use negative values for y. - std::string value_to_uci(Value v) { + string score_to_uci(Value v, Value alpha, Value beta) { std::stringstream s; if (abs(v) < VALUE_MATE - PLY_MAX * ONE_PLY) - s << "cp " << int(v) * 100 / int(PawnValueMidgame); // Scale to centipawns + s << " score cp " << int(v) * 100 / int(PawnValueMidgame); // Scale to centipawns else - s << "mate " << (v > 0 ? VALUE_MATE - v + 1 : -VALUE_MATE - v) / 2; - - return s.str(); - } - + s << " score mate " << (v > 0 ? VALUE_MATE - v + 1 : -VALUE_MATE - v) / 2; - // speed_to_uci() returns a string with time stats of current search suitable - // to be sent to UCI gui. - - std::string speed_to_uci(int64_t nodes) { - - std::stringstream s; - int t = current_search_time(); - - s << " nodes " << nodes - << " nps " << (t > 0 ? int(nodes * 1000 / t) : 0) - << " time " << t; + s << (v >= beta ? " lowerbound" : v <= alpha ? " upperbound" : ""); 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. + // 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. - void poll(const Position& pos) { + void pv_info_to_uci(const Position& pos, int depth, Value alpha, Value beta) { - static int lastInfoTime; - int t = current_search_time(); - - // Poll for input - if (input_available()) - { - // We are line oriented, don't read single chars - std::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; - } - } + int t = elapsed_time(); + int selDepth = 0; - // Print search information - if (t < 1000) - lastInfoTime = 0; + for (int i = 0; i < Threads.size(); i++) + if (Threads[i].maxPly > selDepth) + selDepth = Threads[i].maxPly; - 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) + for (size_t i = 0; i < std::min(UCIMultiPV, RootMoves.size()); i++) { - lastInfoTime = t; + bool updated = (i <= PVIdx); - dbg_print_mean(); - dbg_print_hit_rate(); + if (depth == 1 && !updated) + continue; - // Send info on searched nodes as soon as we return to root - SendSearchedNodes = true; + int d = (updated ? depth : depth - 1); + Value v = (updated ? RootMoves[i].score : RootMoves[i].prevScore); + std::stringstream s; + + for (int j = 0; RootMoves[i].pv[j] != MOVE_NONE; j++) + s << " " << move_to_uci(RootMoves[i].pv[j], Chess960); + + cout << "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" << s.str() << endl; } - - // 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() { - - std::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 - } - - - // init_thread() is the function which is called when a new thread is - // launched. It simply calls the idle_loop() function with the supplied - // threadID. There are two versions of this function; one for POSIX - // threads and one for Windows threads. - -#if !defined(_MSC_VER) - - void* init_thread(void* threadID) { - - ThreadsMgr.idle_loop(*(int*)threadID, NULL); - return NULL; } -#else - - DWORD WINAPI init_thread(LPVOID threadID) { - - ThreadsMgr.idle_loop(*(int*)threadID, NULL); - return 0; - } -#endif + // 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) { - /// The ThreadsManager class + const int MSecMinute = 1000 * 60; + const int MSecHour = 1000 * 60 * 60; + int hours = millisecs / MSecHour; + int minutes = (millisecs % MSecHour) / MSecMinute; + int seconds = ((millisecs % MSecHour) % MSecMinute) / 1000; - // read_uci_options() updates number of active threads and other internal - // parameters according to the UCI options values. It is called before - // to start a new search. + std::stringstream s; - void ThreadsManager::read_uci_options() { + if (hours) + s << hours << ':'; - maxThreadsPerSplitPoint = Options["Maximum Number of Threads per Split Point"].value(); - minimumSplitDepth = Options["Minimum Split Depth"].value() * ONE_PLY; - useSleepingThreads = Options["Use Sleeping Threads"].value(); - activeThreads = Options["Threads"].value(); + s << std::setfill('0') << std::setw(2) << minutes << ':' + << std::setw(2) << seconds; + return s.str(); } + string score_to_string(Value v) { - // idle_loop() is where the threads are parked when they have no work to do. - // The parameter 'sp', if non-NULL, is a pointer to an active SplitPoint - // object for which the current thread is the master. - - void ThreadsManager::idle_loop(int threadID, SplitPoint* sp) { - - assert(threadID >= 0 && threadID < MAX_THREADS); - - int i; - bool allFinished; - - while (true) - { - // Slave threads can exit as soon as AllThreadsShouldExit raises, - // master should exit as last one. - if (allThreadsShouldExit) - { - assert(!sp); - threads[threadID].state = THREAD_TERMINATED; - return; - } - - // If we are not thinking, wait for a condition to be signaled - // instead of wasting CPU time polling for work. - while ( threadID >= activeThreads - || threads[threadID].state == THREAD_INITIALIZING - || (useSleepingThreads && threads[threadID].state == THREAD_AVAILABLE)) - { - assert(!sp || useSleepingThreads); - assert(threadID != 0 || useSleepingThreads); - - if (threads[threadID].state == THREAD_INITIALIZING) - threads[threadID].state = THREAD_AVAILABLE; - - // Grab the lock to avoid races with Thread::wake_up() - lock_grab(&threads[threadID].sleepLock); - - // If we are master and all slaves have finished do not go to sleep - for (i = 0; sp && i < activeThreads && !sp->slaves[i]; i++) {} - allFinished = (i == activeThreads); - - if (allFinished || allThreadsShouldExit) - { - lock_release(&threads[threadID].sleepLock); - break; - } - - // Do sleep here after retesting sleep conditions - if (threadID >= activeThreads || threads[threadID].state == THREAD_AVAILABLE) - cond_wait(&threads[threadID].sleepCond, &threads[threadID].sleepLock); - - lock_release(&threads[threadID].sleepLock); - } - - // If this thread has been assigned work, launch a search - if (threads[threadID].state == THREAD_WORKISWAITING) - { - assert(!allThreadsShouldExit); - - threads[threadID].state = THREAD_SEARCHING; - - // Copy split point position and search stack and call search() - // with SplitPoint template parameter set to true. - SearchStack ss[PLY_MAX_PLUS_2]; - SplitPoint* tsp = threads[threadID].splitPoint; - Position pos(*tsp->pos, threadID); - - memcpy(ss, tsp->ss - 1, 4 * sizeof(SearchStack)); - (ss+1)->sp = tsp; - - if (tsp->pvNode) - search(pos, ss+1, tsp->alpha, tsp->beta, tsp->depth); - else - search(pos, ss+1, tsp->alpha, tsp->beta, tsp->depth); - - assert(threads[threadID].state == THREAD_SEARCHING); - - threads[threadID].state = THREAD_AVAILABLE; - - // Wake up master thread so to allow it to return from the idle loop in - // case we are the last slave of the split point. - if ( useSleepingThreads - && threadID != tsp->master - && threads[tsp->master].state == THREAD_AVAILABLE) - threads[tsp->master].wake_up(); - } - - // 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. - for (i = 0; sp && i < activeThreads && !sp->slaves[i]; i++) {} - allFinished = (i == activeThreads); - - if (allFinished) - { - // Because sp->slaves[] is reset under lock protection, - // be sure sp->lock has been released before to return. - lock_grab(&(sp->lock)); - lock_release(&(sp->lock)); + std::stringstream s; - // In helpful master concept a master can help only a sub-tree, and - // because here is all finished is not possible master is booked. - assert(threads[threadID].state == THREAD_AVAILABLE); + if (v >= VALUE_MATE_IN_PLY_MAX) + s << "#" << (VALUE_MATE - v + 1) / 2; + 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; - threads[threadID].state = THREAD_SEARCHING; - return; - } - } + return s.str(); } + void pv_info_to_log(Position& pos, int depth, Value value, int time, Move pv[]) { - // init_threads() is called during startup. Initializes locks and condition - // variables and launches all threads sending them immediately to sleep. + const int64_t K = 1000; + const int64_t M = 1000000; - void ThreadsManager::init_threads() { - - int i, arg[MAX_THREADS]; - bool ok; + StateInfo state[PLY_MAX_PLUS_2], *st = state; + Move* m = pv; + string san, padding; + size_t length; + std::stringstream s; - // This flag is needed to properly end the threads when program exits - allThreadsShouldExit = false; + s << std::setw(2) << depth + << std::setw(8) << score_to_string(value) + << std::setw(8) << time_to_string(time); - // Threads will sent to sleep as soon as created, only main thread is kept alive - activeThreads = 1; + if (pos.nodes_searched() < M) + s << std::setw(8) << pos.nodes_searched() / 1 << " "; - lock_init(&mpLock); + else if (pos.nodes_searched() < K * M) + s << std::setw(7) << pos.nodes_searched() / K << "K "; - for (i = 0; i < MAX_THREADS; i++) - { - // Initialize thread and split point locks - lock_init(&threads[i].sleepLock); - cond_init(&threads[i].sleepCond); - - for (int j = 0; j < MAX_ACTIVE_SPLIT_POINTS; j++) - lock_init(&(threads[i].splitPoints[j].lock)); + else + s << std::setw(7) << pos.nodes_searched() / M << "M "; - // All threads but first should be set to THREAD_INITIALIZING - threads[i].state = (i == 0 ? THREAD_SEARCHING : THREAD_INITIALIZING); - } + padding = string(s.str().length(), ' '); + length = padding.length(); - // Create and startup the threads - for (i = 1; i < MAX_THREADS; i++) + while (*m != MOVE_NONE) { - arg[i] = i; - -#if !defined(_MSC_VER) - pthread_t pthread[1]; - ok = (pthread_create(pthread, NULL, init_thread, (void*)(&arg[i])) == 0); - pthread_detach(pthread[0]); -#else - ok = (CreateThread(NULL, 0, init_thread, (LPVOID)(&arg[i]), 0, NULL) != NULL); -#endif - if (!ok) - { - cout << "Failed to create thread number " << i << endl; - exit(EXIT_FAILURE); - } - - // Wait until the thread has finished launching and is gone to sleep - while (threads[i].state == THREAD_INITIALIZING) {} - } - } - - - // exit_threads() is called when the program exits. It makes all the - // helper threads exit cleanly. - - void ThreadsManager::exit_threads() { + san = move_to_san(pos, *m); - // Force the woken up threads to exit idle_loop() and hence terminate - allThreadsShouldExit = true; - - for (int i = 0; i < MAX_THREADS; i++) - { - // Wake up all the threads and waits for termination - if (i != 0) + if (length + san.length() > 80) { - threads[i].wake_up(); - while (threads[i].state != THREAD_TERMINATED) {} + s << "\n" + padding; + length = padding.length(); } - // Now we can safely destroy the locks and wait conditions - lock_destroy(&threads[i].sleepLock); - cond_destroy(&threads[i].sleepCond); + s << san << ' '; + length += san.length() + 1; - for (int j = 0; j < MAX_ACTIVE_SPLIT_POINTS; j++) - lock_destroy(&(threads[i].splitPoints[j].lock)); + pos.do_move(*m++, *st++); } - lock_destroy(&mpLock); - } - + while (m != pv) + pos.undo_move(*--m); - // cutoff_at_splitpoint() checks whether a beta cutoff has occurred in - // the thread's currently active split point, or in some ancestor of - // the current split point. - - bool ThreadsManager::cutoff_at_splitpoint(int threadID) const { - - assert(threadID >= 0 && threadID < activeThreads); - - SplitPoint* sp = threads[threadID].splitPoint; - - for ( ; sp && !sp->betaCutoff; sp = sp->parent) {} - return sp != NULL; + Log l(Options["Search Log Filename"].value()); + l << s.str() << endl; } - // thread_is_available() checks whether the thread with threadID "slave" is - // available to help the thread with threadID "master" at a split point. An - // obvious requirement is that "slave" must be idle. With more than two - // threads, this is not by itself sufficient: If "slave" is the master of - // some active split point, it is only available as a slave to the other - // threads which are busy searching the split point at the top of "slave"'s - // split point stack (the "helpful master concept" in YBWC terminology). - - bool ThreadsManager::thread_is_available(int slave, int master) const { - - assert(slave >= 0 && slave < activeThreads); - assert(master >= 0 && master < activeThreads); - assert(activeThreads > 1); - - if (threads[slave].state != THREAD_AVAILABLE || slave == master) - return false; - - // Make a local copy to be sure doesn't change under our feet - int localActiveSplitPoints = threads[slave].activeSplitPoints; - - // No active split points means that the thread is available as - // a slave for any other thread. - if (localActiveSplitPoints == 0 || activeThreads == 2) - return true; - - // Apply the "helpful master" concept if possible. Use localActiveSplitPoints - // that is known to be > 0, instead of threads[slave].activeSplitPoints that - // could have been set to 0 by another thread leading to an out of bound access. - if (threads[slave].splitPoints[localActiveSplitPoints - 1].slaves[master]) - return true; - - return 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. + Move do_skill_level() { - // available_thread_exists() tries to find an idle thread which is available as - // a slave for the thread with threadID "master". + assert(MultiPV > 1); - bool ThreadsManager::available_thread_exists(int master) const { + static RKISS rk; - assert(master >= 0 && master < activeThreads); - assert(activeThreads > 1); - - for (int i = 0; i < activeThreads; i++) - if (thread_is_available(i, master)) - return true; - - return false; - } + // PRNG sequence should be not deterministic + for (int i = abs(system_time() % 50); i > 0; i--) + rk.rand(); + // 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; - // split() does the actual work of distributing the work at a node between - // several available threads. If it does not succeed in splitting the - // node (because no idle threads are available, or because we have no unused - // split point objects), the function immediately returns. If splitting is - // possible, a SplitPoint object is initialized with all the data that must be - // copied to the helper threads and we tell our helper threads that they have - // been assigned work. This will cause them to instantly leave their idle loops and - // call search().When all threads have returned from search() then split() returns. - - template - void ThreadsManager::split(Position& pos, SearchStack* ss, Value* alpha, const Value beta, - Value* bestValue, Depth depth, Move threatMove, - int moveCount, MovePicker* mp, bool pvNode) { - assert(pos.is_ok()); - assert(*bestValue >= -VALUE_INFINITE); - assert(*bestValue <= *alpha); - assert(*alpha < beta); - assert(beta <= VALUE_INFINITE); - assert(depth > DEPTH_ZERO); - assert(pos.thread() >= 0 && pos.thread() < activeThreads); - assert(activeThreads > 1); - - int i, master = pos.thread(); - Thread& masterThread = threads[master]; - - lock_grab(&mpLock); - - // If no other thread is available to help us, or if we have too many - // active split points, don't split. - if ( !available_thread_exists(master) - || masterThread.activeSplitPoints >= MAX_ACTIVE_SPLIT_POINTS) + // 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++) { - lock_release(&mpLock); - return; - } - - // Pick the next available split point object from the split point stack - SplitPoint& splitPoint = masterThread.splitPoints[masterThread.activeSplitPoints++]; - - // Initialize the split point object - splitPoint.parent = masterThread.splitPoint; - splitPoint.master = master; - splitPoint.betaCutoff = false; - splitPoint.depth = depth; - splitPoint.threatMove = threatMove; - splitPoint.alpha = *alpha; - splitPoint.beta = beta; - splitPoint.pvNode = pvNode; - splitPoint.bestValue = *bestValue; - splitPoint.mp = mp; - splitPoint.moveCount = moveCount; - splitPoint.pos = &pos; - splitPoint.nodes = 0; - splitPoint.ss = ss; - for (i = 0; i < activeThreads; i++) - splitPoint.slaves[i] = 0; - - masterThread.splitPoint = &splitPoint; - - // If we are here it means we are not available - assert(masterThread.state != THREAD_AVAILABLE); - - int workersCnt = 1; // At least the master is included - - // Allocate available threads setting state to THREAD_BOOKED - for (i = 0; !Fake && i < activeThreads && workersCnt < maxThreadsPerSplitPoint; i++) - if (thread_is_available(i, master)) - { - threads[i].state = THREAD_BOOKED; - threads[i].splitPoint = &splitPoint; - splitPoint.slaves[i] = 1; - workersCnt++; - } + int s = RootMoves[i].score; - assert(Fake || workersCnt > 1); + // Don't allow crazy blunders even at very low skills + if (i > 0 && RootMoves[i-1].score > s + EasyMoveMargin) + break; - // We can release the lock because slave threads are already booked and master is not available - lock_release(&mpLock); + // This is our magic formula + s += ( weakness * int(RootMoves[0].score - s) + + variance * (rk.rand() % weakness)) / 128; - // Tell the threads that they have work to do. This will make them leave - // their idle loop. - for (i = 0; i < activeThreads; i++) - if (i == master || splitPoint.slaves[i]) + if (s > max_s) { - assert(i == master || threads[i].state == THREAD_BOOKED); - - threads[i].state = THREAD_WORKISWAITING; // This makes the slave to exit from idle_loop() - - if (useSleepingThreads && i != master) - threads[i].wake_up(); + max_s = s; + best = RootMoves[i].pv[0]; } - - // Everything is set up. The master thread enters the idle loop, from - // which it will instantly launch a search, because its state is - // THREAD_WORKISWAITING. We send the split point as a second parameter to the - // idle loop, which means that the main thread will return from the idle - // loop when all threads have finished their work at this split point. - idle_loop(master, &splitPoint); - - // We have returned from the idle loop, which means that all threads are - // finished. Update alpha and bestValue, and return. - lock_grab(&mpLock); - - *alpha = splitPoint.alpha; - *bestValue = splitPoint.bestValue; - masterThread.activeSplitPoints--; - masterThread.splitPoint = splitPoint.parent; - pos.set_nodes_searched(pos.nodes_searched() + splitPoint.nodes); - - lock_release(&mpLock); - } - - - /// RootMove and RootMoveList method's definitions - - RootMove::RootMove() { - - nodes = 0; - pv_score = non_pv_score = -VALUE_INFINITE; - pv[0] = MOVE_NONE; + } + return best; } - RootMove& RootMove::operator=(const RootMove& rm) { - - const Move* src = rm.pv; - Move* dst = pv; - - // Avoid a costly full rm.pv[] copy - do *dst++ = *src; while (*src++ != MOVE_NONE); - - nodes = rm.nodes; - pv_score = rm.pv_score; - non_pv_score = rm.non_pv_score; - return *this; - } // 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 @@ -2420,25 +1813,31 @@ split_point_start: // At split points actual search starts from here StateInfo state[PLY_MAX_PLUS_2], *st = state; TTEntry* tte; int ply = 1; + Move m = pv[0]; - assert(pv[0] != MOVE_NONE && pos.move_is_legal(pv[0])); + assert(m != MOVE_NONE && pos.is_pseudo_legal(m)); - pos.do_move(pv[0], *st++); + pv.clear(); + pv.push_back(m); + pos.do_move(m, *st++); - while ( (tte = TT.retrieve(pos.get_key())) != NULL + while ( (tte = TT.probe(pos.key())) != NULL && tte->move() != MOVE_NONE - && pos.move_is_legal(tte->move()) + && pos.is_pseudo_legal(tte->move()) + && pos.pl_move_is_legal(tte->move(), pos.pinned_pieces()) && ply < PLY_MAX - && (!pos.is_draw() || ply < 2)) + && (!pos.is_draw() || ply < 2)) { - pv[ply] = tte->move(); - pos.do_move(pv[ply++], *st++); + pv.push_back(tte->move()); + pos.do_move(tte->move(), *st++); + ply++; } - pv[ply] = MOVE_NONE; + pv.push_back(MOVE_NONE); 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. @@ -2451,16 +1850,16 @@ 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.move_is_legal(pv[0])); + assert(pv[ply] != MOVE_NONE && pos.is_pseudo_legal(pv[ply])); do { - k = pos.get_key(); - tte = TT.retrieve(k); + k = pos.key(); + tte = TT.probe(k); // Don't overwrite existing correct entries if (!tte || tte->move() != pv[ply]) { - v = (pos.is_check() ? VALUE_NONE : evaluate(pos, m)); + v = (pos.in_check() ? VALUE_NONE : evaluate(pos, m)); TT.store(k, VALUE_NONE, VALUE_TYPE_NONE, DEPTH_NONE, pv[ply], v, m); } pos.do_move(pv[ply], *st++); @@ -2470,95 +1869,128 @@ split_point_start: // At split points actual search starts from here do pos.undo_move(pv[--ply]); while (ply); } - // pv_info_to_uci() returns a string with information on the current PV line - // formatted according to UCI specification. +} // namespace - std::string RootMove::pv_info_to_uci(Position& pos, int depth, int selDepth, Value alpha, - Value beta, int pvIdx) { - std::stringstream s; - s << "info depth " << depth - << " seldepth " << selDepth - << " multipv " << pvIdx + 1 - << " score " << value_to_uci(pv_score) - << (pv_score >= beta ? " lowerbound" : pv_score <= alpha ? " upperbound" : "") - << speed_to_uci(pos.nodes_searched()) - << " pv "; +/// 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. - for (Move* m = pv; *m != MOVE_NONE; m++) - s << *m << " "; +void Thread::idle_loop(SplitPoint* sp) { - return s.str(); - } + while (true) + { + // If we are not searching, wait for a condition to be signaled + // instead of wasting CPU time polling for work. + while ( do_sleep + || do_terminate + || (Threads.use_sleeping_threads() && !is_searching)) + { + assert((!sp && threadID) || Threads.use_sleeping_threads()); + if (do_terminate) + { + assert(!sp); + return; + } - void RootMoveList::init(Position& pos, Move searchMoves[]) { + // Grab the lock to avoid races with Thread::wake_up() + lock_grab(&sleepLock); - MoveStack mlist[MOVES_MAX]; - Move* sm; + // If we are master and all slaves have finished don't go to sleep + if (sp && Threads.split_point_finished(sp)) + { + lock_release(&sleepLock); + break; + } - clear(); - bestMoveChanges = 0; + // Do sleep after retesting sleep conditions under lock protection, in + // particular we need to avoid a deadlock in case a master thread has, + // in the meanwhile, allocated us and sent the wake_up() call before we + // had the chance to grab the lock. + if (do_sleep || !is_searching) + cond_wait(&sleepCond, &sleepLock); - // Generate all legal moves and add them to RootMoveList - MoveStack* last = generate(pos, mlist); - for (MoveStack* cur = mlist; cur != last; cur++) - { - // If we have a searchMoves[] list then verify cur->move - // is in the list before to add it. - for (sm = searchMoves; *sm && *sm != cur->move; sm++) {} + lock_release(&sleepLock); + } - if (searchMoves[0] && *sm != cur->move) - continue; + // If this thread has been assigned work, launch a search + if (is_searching) + { + assert(!do_terminate); + + // Copy split point position and search stack and call search() + Stack ss[PLY_MAX_PLUS_2]; + SplitPoint* tsp = splitPoint; + Position pos(*tsp->pos, threadID); + + memcpy(ss, tsp->ss - 1, 4 * sizeof(Stack)); + (ss+1)->sp = tsp; + + if (tsp->nodeType == Root) + search(pos, ss+1, tsp->alpha, tsp->beta, tsp->depth); + else if (tsp->nodeType == PV) + search(pos, ss+1, tsp->alpha, tsp->beta, tsp->depth); + else if (tsp->nodeType == NonPV) + search(pos, ss+1, tsp->alpha, tsp->beta, tsp->depth); + else + assert(false); - RootMove rm; - rm.pv[0] = cur->move; - rm.pv[1] = MOVE_NONE; - rm.pv_score = -VALUE_INFINITE; - push_back(rm); - } - } + assert(is_searching); + is_searching = 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) { + // Wake up master thread so to allow it to return from the idle loop in + // case we are the last slave of the split point. + if ( Threads.use_sleeping_threads() + && threadID != tsp->master + && !Threads[tsp->master].is_searching) + Threads[tsp->master].wake_up(); + } - assert(MultiPV > 1); + // 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 && Threads.split_point_finished(sp)) + { + // Because sp->is_slave[] is reset under lock protection, + // be sure sp->lock has been released before to return. + lock_grab(&(sp->lock)); + lock_release(&(sp->lock)); + return; + } + } +} - // Rml list is already sorted by pv_score in descending order - int s; - int max_s = -VALUE_INFINITE; - int size = Min(MultiPV, (int)Rml.size()); - int max = Rml[0].pv_score; - int var = Min(max - Rml[size - 1].pv_score, PawnValueMidgame); - int wk = 120 - 2 * SkillLevel; - // PRNG sequence should be non deterministic - for (int i = abs(get_system_time() % 50); i > 0; i--) - RK.rand(); +/// 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. - // 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, - // then we choose the move with the resulting highest score. - for (int i = 0; i < size; i++) - { - s = Rml[i].pv_score; +void do_timer_event() { - // Don't allow crazy blunders even at very low skills - if (i > 0 && Rml[i-1].pv_score > s + EasyMoveMargin) - break; + static int lastInfoTime; + int e = elapsed_time(); - // This is our magical formula - s += ((max - s) * wk + var * (RK.rand() % wk)) / 128; + if (system_time() - lastInfoTime >= 1000 || !lastInfoTime) + { + lastInfoTime = system_time(); - if (s > max_s) - { - max_s = s; - *best = Rml[i].pv[0]; - *ponder = Rml[i].pv[1]; - } - } + dbg_print_mean(); + dbg_print_hit_rate(); } -} // namespace + 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; +}