X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=0318d63138ea41dd9913808c221e2540d617f8b0;hp=1b6cf365b427ca10e38252896666bb8f302879ea;hb=ca9d40c1455ee721d84b234f60afcdc5a2e5b0fa;hpb=5405efabcbd1b60f64a5d88b596178dcf92e98e4 diff --git a/src/search.cpp b/src/search.cpp index 1b6cf365..0318d631 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -17,11 +17,6 @@ along with this program. If not, see . */ - -//// -//// Includes -//// - #include #include #include @@ -34,10 +29,9 @@ #include "evaluate.h" #include "history.h" #include "misc.h" +#include "move.h" #include "movegen.h" #include "movepick.h" -#include "lock.h" -#include "san.h" #include "search.h" #include "timeman.h" #include "thread.h" @@ -47,70 +41,19 @@ using std::cout; using std::endl; -//// -//// Local definitions -//// - namespace { - // Types - enum NodeType { NonPV, PV }; - - // Set to true to force running with one thread. - // Used for debugging SMP code. + // Set to true to force running with one thread. Used for debugging const bool FakeSplit = false; - // Fast lookup table of sliding pieces indexed by Piece - 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 in search, - // init, starting, parking and, the most important, launching a slave thread at a - // split point are what this class does. All the access to shared thread data is - // done through this class, so that we avoid using global variables instead. - - 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: - 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 wake_sleeping_thread(int threadID); - void idle_loop(int threadID, SplitPoint* sp); - - template - void split(Position& pos, SearchStack* ss, int ply, Value* alpha, const Value beta, Value* bestValue, - Depth depth, Move threatMove, bool mateThreat, int moveCount, MovePicker* mp, bool pvNode); - - private: - Depth minimumSplitDepth; - int maxThreadsPerSplitPoint; - bool useSleepingThreads; - int activeThreads; - volatile bool allThreadsShouldExit; - Thread threads[MAX_THREADS]; - Lock mpLock, sleepLock[MAX_THREADS]; - WaitCondition sleepCond[MAX_THREADS]; - }; - + // Different node types, used as template parameter + enum NodeType { NonPV, PV }; - // RootMove struct is used for moves at the root at the tree. For each root + // 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. - struct RootMove { RootMove(); @@ -120,8 +63,8 @@ namespace { // 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. + // 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; @@ -129,46 +72,66 @@ namespace { void extract_pv_from_tt(Position& pos); void insert_pv_in_tt(Position& pos); - std::string pv_info_to_uci(const Position& pos, Value alpha, Value beta, int pvLine = 0); - + 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 essentially a std::vector<> of RootMove objects, + // 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; - RootMoveList(Position& pos, Move searchMoves[]); - void set_non_pv_scores(const Position& pos); - + void init(Position& pos, Move searchMoves[]); void sort() { insertion_sort(begin(), end()); } void sort_multipv(int n) { insertion_sort(begin(), begin() + n); } + + int bestMoveChanges; }; + // MovePickerExt template class extends MovePicker and allows to choose at compile + // time the proper moves source according to the type of node. In the default case + // we simply create and use a standard MovePicker object. + template struct MovePickerExt : public MovePicker { - // 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 use it to properly format castling moves. - enum set960 {}; + MovePickerExt(const Position& p, Move ttm, Depth d, const History& h, SearchStack* ss, Value b) + : MovePicker(p, ttm, d, h, ss, b) {} - std::ostream& operator<< (std::ostream& os, const set960& m) { + RootMoveList::iterator rm; // Dummy, needed to compile + }; - os.iword(0) = int(m); - return os; - } + // 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) + : 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 + MovePicker* mp; + }; + // In case of a Root node we use RootMoveList as moves source + template<> struct MovePickerExt : public MovePicker { - /// Adjustments + MovePickerExt(const Position&, Move, Depth, const History&, SearchStack*, Value); + Move get_next_move(); + + RootMoveList::iterator rm; + bool firstCall; + }; + + + /// Constants + + // 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]; } // Step 6. Razoring @@ -184,7 +147,7 @@ namespace { // 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. @@ -192,42 +155,44 @@ namespace { // 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], SingleEvasionExtension[2], PawnPushTo7thExtension[2]; - Depth PassedPawnExtension[2], PawnEndgameExtension[2], MateThreatExtension[2]; + // Extensions. Array index 0 is used for non-PV nodes, index 1 for PV nodes + const Depth CheckExtension[] = { ONE_PLY / 2, ONE_PLY / 1 }; + const Depth PawnEndgameExtension[] = { ONE_PLY / 1, ONE_PLY / 1 }; + const Depth PawnPushTo7thExtension[] = { ONE_PLY / 2, ONE_PLY / 2 }; + const Depth PassedPawnExtension[] = { DEPTH_ZERO, ONE_PLY / 2 }; // Minimum depth for use of singular extension - const Depth SingularExtensionDepth[2] = { 8 * ONE_PLY /* non-PV */, 6 * ONE_PLY /* PV */}; - - // If the TT move is at least SingularExtensionMargin better then the - // remaining ones we will extend it. - const Value SingularExtensionMargin = Value(0x20); + const Depth SingularExtensionDepth[] = { 8 * ONE_PLY, 6 * ONE_PLY }; // Step 12. Futility pruning // Futility margin for quiescence search const Value FutilityMarginQS = Value(0x80); - // Futility lookup tables (initialized at startup) and their getter functions - Value FutilityMarginsMatrix[16][64]; // [depth][moveNumber] - int FutilityMoveCountArray[32]; // [depth] + // Futility lookup tables (initialized at startup) and their access functions + 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[Max(d, 1)][Min(mn, 63)] + : 2 * VALUE_INFINITE; + } - // Reduction lookup tables (initialized at startup) and their getter functions - int8_t ReductionMatrix[2][64][64]; // [pv][depth][moveNumber] + inline int futility_move_count(Depth d) { - template - inline Depth reduction(Depth d, int mn) { return (Depth) ReductionMatrix[PV][Min(d / 2, 63)][Min(mn, 63)]; } + return d < 16 * ONE_PLY ? FutilityMoveCounts[d] : MAX_MOVES; + } - // Common adjustments + // Step 14. Reduced search - // Search depth at iteration 1 - const Depth InitialDepth = ONE_PLY; + // Reduction lookup tables (initialized at startup) and their access function + int8_t Reductions[2][64][64]; // [pv][depth][moveNumber] + + template inline Depth reduction(Depth d, int mn) { + + return (Depth) Reductions[PV][Min(d / ONE_PLY, 63)][Min(mn, 63)]; + } // Easy move margin. An easy move candidate must be at least this much // better than the second best move. @@ -236,34 +201,23 @@ namespace { /// Namespace variables - // Book object - Book OpeningBook; - - // Iteration counter - int Iteration; - - // Scores and number of times the best move changed for each iteration - Value ValueByIteration[PLY_MAX_PLUS_2]; - int BestMoveChangesByIteration[PLY_MAX_PLUS_2]; - - // Search window management - int AspirationDelta; + // Root move list + RootMoveList Rml; // MultiPV mode - int MultiPV; + int MultiPV, UCIMultiPV; - // Time managment variables - int SearchStartTime, MaxNodes, MaxDepth, ExactMaxTime; - bool UseTimeManagement, InfiniteSearch, Pondering, StopOnPonderhit; - bool FirstRootMove, StopRequest, QuitRequest, AspirationFailLow; + // Time management variables + bool StopOnPonderhit, FirstRootMove, StopRequest, QuitRequest, AspirationFailLow; TimeManager TimeMgr; + SearchLimits Limits; // Log file - bool UseLogFile; std::ofstream LogFile; - // Multi-threads manager object - ThreadsManager ThreadsMgr; + // Skill level adjustment + int SkillLevel; + bool SkillLevelEnabled; // Node counters, used only by thread[0] but try to keep in different cache // lines (64 bytes each) from the heavy multi-thread read accessed variables. @@ -274,67 +228,70 @@ namespace { // History table History H; + /// Local functions Move id_loop(Position& pos, Move searchMoves[], Move* ponderMove); - Value root_search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth, RootMoveList& rml); - template - Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth, int ply); + template + Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth); template - Value qsearch(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth, int ply); + 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, int ply) { + inline Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth) { - return depth < ONE_PLY ? qsearch(pos, ss, alpha, beta, DEPTH_ZERO, ply) - : search(pos, ss, alpha, beta, depth, ply); + 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 singleEvasion, bool mateThreat, bool* dangerous); + Depth extension(const Position& pos, Move m, bool captureOrPromotion, bool moveIsCheck, bool* dangerous); bool check_is_dangerous(Position &pos, Move move, Value futilityBase, Value beta, Value *bValue); bool connected_moves(const Position& pos, Move m1, Move m2); - bool value_is_mate(Value value); 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 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_killers(Move m, SearchStack* ss); 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 current_search_time(int set = 0); std::string value_to_uci(Value v); - int nps(const Position& pos); + std::string speed_to_uci(int64_t nodes); void poll(const Position& pos); void wait_for_stop_or_ponderhit(); - void init_ss_array(SearchStack* ss, int size); -#if !defined(_MSC_VER) - void* init_thread(void* threadID); -#else - DWORD WINAPI init_thread(LPVOID threadID); -#endif + // 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 {}; -//// -//// Functions -//// + std::ostream& operator<< (std::ostream& os, const set960& f) { -/// init_threads(), exit_threads() and nodes_searched() are helpers to -/// give accessibility to some TM methods from outside of current file. + os.iword(0) = int(f); + return os; + } -void init_threads() { ThreadsMgr.init_threads(); } -void exit_threads() { ThreadsMgr.exit_threads(); } +} // namespace -/// init_search() is called during startup. It initializes various lookup tables +/// init_search() is called during startup to initialize various lookup tables void init_search() { @@ -347,80 +304,87 @@ void init_search() { { 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[PV][hd][mc] = (int8_t) ( pvRed >= 1.0 ? floor( pvRed * int(ONE_PLY)) : 0); + Reductions[NonPV][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)); + FutilityMoveCounts[d] = int(3.001 + 0.25 * pow(d, 2.0)); } -/// perft() is our utility to verify move generation is bug free. All the legal -/// moves up to given depth are generated and counted and the sum returned. +/// perft() is our utility to verify move generation. All the legal moves up to +/// given depth are generated and counted and the sum returned. -int perft(Position& pos, Depth depth) -{ - MoveStack mlist[MOVES_MAX]; - StateInfo st; - Move m; - int sum = 0; +int64_t perft(Position& pos, Depth depth) { - // Generate all legal moves - MoveStack* last = generate_moves(pos, mlist); + MoveStack mlist[MAX_MOVES]; + StateInfo st; + Move m; + int64_t sum = 0; - // If we are at the last ply we don't need to do and undo - // the moves, just to count them. - if (depth <= ONE_PLY) - return int(last - mlist); + // Generate all legal moves + MoveStack* last = generate(pos, mlist); - // Loop through all legal moves - CheckInfo ci(pos); - for (MoveStack* cur = mlist; cur != last; cur++) - { - m = cur->move; - pos.do_move(m, st, ci, pos.move_is_check(m, ci)); - sum += perft(pos, depth - ONE_PLY); - pos.undo_move(m); - } - return sum; + // If we are at the last ply we don't need to do and undo + // the moves, just to count them. + if (depth <= ONE_PLY) + return int(last - mlist); + + // Loop through all legal moves + CheckInfo ci(pos); + for (MoveStack* cur = mlist; cur != last; cur++) + { + m = cur->move; + pos.do_move(m, st, ci, pos.move_is_check(m, ci)); + sum += perft(pos, depth - ONE_PLY); + pos.undo_move(m); + } + return sum; } /// think() is the external interface to Stockfish's search, and is called when -/// the program receives the UCI 'go' command. It initializes various -/// search-related global variables, and calls root_search(). It returns false -/// when a quit command is received during the search. +/// 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. -bool think(Position& pos, bool infinite, bool ponder, int time[], int increment[], - int movesToGo, int maxDepth, int maxNodes, int maxTime, Move searchMoves[]) { +bool think(Position& pos, const SearchLimits& limits, Move searchMoves[]) { - // Initialize global search variables + static Book book; + + // Initialize global search-related variables StopOnPonderhit = StopRequest = QuitRequest = AspirationFailLow = SendSearchedNodes = false; NodesSincePoll = 0; - SearchStartTime = get_system_time(); - ExactMaxTime = maxTime; - MaxDepth = maxDepth; - MaxNodes = maxNodes; - InfiniteSearch = infinite; - Pondering = ponder; - UseTimeManagement = !ExactMaxTime && !MaxDepth && !MaxNodes && !InfiniteSearch; - - // Look for a book move, only during games, not tests - if (UseTimeManagement && Options["OwnBook"].value()) + current_search_time(get_system_time()); + Limits = limits; + TimeMgr.init(Limits, pos.startpos_ply_counter()); + + // 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 + if (Options["OwnBook"].value()) { - if (Options["Book File"].value() != OpeningBook.file_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()); + Move bookMove = book.get_move(pos, Options["Best Book Move"].value()); if (bookMove != MOVE_NONE) { - if (Pondering) + if (Limits.ponder) wait_for_stop_or_ponderhit(); cout << "bestmove " << bookMove << endl; @@ -428,104 +392,90 @@ bool think(Position& pos, bool infinite, bool ponder, int time[], int increment[ } } - // Read UCI option values + // Read UCI options + UCIMultiPV = Options["MultiPV"].value(); + SkillLevel = Options["Skill level"].value(); + + read_evaluation_uci_options(pos.side_to_move()); + Threads.read_uci_options(); + + // If needed allocate pawn and material hash tables and adjust TT size + Threads.init_hash_tables(); TT.set_size(Options["Hash"].value()); + if (Options["Clear Hash"].value()) { Options["Clear Hash"].set_value("false"); TT.clear(); } - CheckExtension[1] = Options["Check Extension (PV nodes)"].value(); - CheckExtension[0] = Options["Check Extension (non-PV nodes)"].value(); - SingleEvasionExtension[1] = Options["Single Evasion Extension (PV nodes)"].value(); - SingleEvasionExtension[0] = Options["Single Evasion 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(); - MateThreatExtension[1] = Options["Mate Threat Extension (PV nodes)"].value(); - MateThreatExtension[0] = Options["Mate Threat Extension (non-PV nodes)"].value(); - MultiPV = Options["MultiPV"].value(); - UseLogFile = Options["Use Search Log"].value(); - - read_evaluation_uci_options(pos.side_to_move()); + // 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()); - - // Wake up needed threads - for (int i = 1; i < ThreadsMgr.active_threads(); i++) - ThreadsMgr.wake_sleeping_thread(i); - - // Set thinking time - int myTime = time[pos.side_to_move()]; - int myIncrement = increment[pos.side_to_move()]; - if (UseTimeManagement) - TimeMgr.init(myTime, myIncrement, movesToGo, pos.startpos_ply_counter()); - - // Set best NodesBetweenPolls interval to avoid lagging under - // heavy time pressure. - if (MaxNodes) - NodesBetweenPolls = Min(MaxNodes, 30000); - else if (myTime && myTime < 1000) - NodesBetweenPolls = 1000; - else if (myTime && myTime < 5000) - NodesBetweenPolls = 5000; - else - NodesBetweenPolls = 30000; + // Wake up needed threads and reset maxPly counter + for (int i = 0; i < Threads.size(); i++) + { + Threads[i].wake_up(); + Threads[i].maxPly = 0; + } - // Write search information to log file - if (UseLogFile) + // Write to log file and keep it open to be accessed during the search + if (Options["Use Search Log"].value()) { std::string name = Options["Search Log Filename"].value(); LogFile.open(name.c_str(), std::ios::out | std::ios::app); - LogFile << "Searching: " << pos.to_fen() - << "\ninfinite: " << infinite - << " ponder: " << ponder - << " time: " << myTime - << " increment: " << myIncrement - << " moves to go: " << movesToGo << endl; + if (LogFile.is_open()) + LogFile << "\nSearching: " << pos.to_fen() + << "\ninfinite: " << Limits.infinite + << " ponder: " << Limits.ponder + << " time: " << Limits.time + << " increment: " << Limits.increment + << " moves to go: " << Limits.movesToGo + << endl; } // We're ready to start thinking. Call the iterative deepening loop function Move ponderMove = MOVE_NONE; Move bestMove = id_loop(pos, searchMoves, &ponderMove); - // Print final search statistics - cout << "info nodes " << pos.nodes_searched() - << " nps " << nps(pos) - << " time " << current_search_time() << endl; + cout << "info" << speed_to_uci(pos.nodes_searched()) << endl; - if (UseLogFile) + // Write final search statistics and close log file + if (LogFile.is_open()) { - LogFile << "\nNodes: " << pos.nodes_searched() - << "\nNodes/second: " << nps(pos) - << "\nBest move: " << move_to_san(pos, bestMove); + int t = current_search_time(); + + LogFile << "Nodes: " << pos.nodes_searched() + << "\nNodes/second: " << (t > 0 ? pos.nodes_searched() * 1000 / t : 0) + << "\nBest move: " << move_to_san(pos, bestMove); StateInfo st; pos.do_move(bestMove, st); - LogFile << "\nPonder move: " - << move_to_san(pos, ponderMove) // Works also with MOVE_NONE - << endl; - + LogFile << "\nPonder move: " << move_to_san(pos, ponderMove) << endl; + pos.undo_move(bestMove); // Return from think() with unchanged position LogFile.close(); } // This makes all the threads to go to sleep - ThreadsMgr.set_active_threads(1); + Threads.set_size(1); // If we are pondering or in infinite search, we shouldn't print the // best move before we are told to do so. - if (!StopRequest && (Pondering || InfiniteSearch)) + if (!StopRequest && (Limits.ponder || Limits.infinite)) wait_for_stop_or_ponderhit(); - // Could be both MOVE_NONE when searching on a stalemate position - cout << "bestmove " << bestMove << " ponder " << ponderMove << endl; + // 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; } @@ -533,380 +483,176 @@ bool think(Position& pos, bool infinite, bool ponder, int time[], int increment[ namespace { - // id_loop() is the main iterative deepening loop. It calls root_search - // repeatedly with increasing depth until the allocated thinking time has - // been consumed, the user stops the search, or the maximum search depth is - // reached. + // id_loop() is the main iterative deepening loop. It calls search() repeatedly + // 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]; - Depth depth; - Move EasyMove = MOVE_NONE; - Value value, alpha = -VALUE_INFINITE, beta = VALUE_INFINITE; + 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, scored and sorted - RootMoveList rml(pos, searchMoves); + // Moves to search are verified and copied + Rml.init(pos, searchMoves); - // Handle special case of searching on a mate/stale position - if (rml.size() == 0) + // Handle special case of searching on a mate/stalemate position + if (Rml.size() == 0) { - Value s = (pos.is_check() ? -VALUE_MATE : VALUE_DRAW); - - cout << "info depth " << 1 - << " score " << value_to_uci(s) << endl; + cout << "info depth 0 score " + << value_to_uci(pos.is_check() ? -VALUE_MATE : VALUE_DRAW) + << endl; return MOVE_NONE; } - // Initialize - TT.new_search(); - H.clear(); - init_ss_array(ss, PLY_MAX_PLUS_2); - ValueByIteration[1] = rml[0].pv_score; - Iteration = 1; - - // Send initial RootMoveList scoring (iteration 1) - cout << set960(pos.is_chess960()) // Is enough to set once at the beginning - << "info depth " << Iteration - << "\n" << rml[0].pv_info_to_uci(pos, alpha, beta) << endl; - - // Is one move significantly better than others after initial scoring ? - if ( rml.size() == 1 - || rml[0].pv_score > rml[1].pv_score + EasyMoveMargin) - EasyMove = rml[0].pv[0]; - - // Iterative deepening loop - while (Iteration < PLY_MAX) + // Iterative deepening loop until requested to stop or target depth reached + while (!StopRequest && ++depth <= PLY_MAX && (!Limits.maxDepth || depth <= Limits.maxDepth)) { - // Initialize iteration - Iteration++; - BestMoveChangesByIteration[Iteration] = 0; - - cout << "info depth " << Iteration << endl; + Rml.bestMoveChanges = 0; + cout << set960(pos.is_chess960()) << "info depth " << depth << endl; // Calculate dynamic aspiration window based on previous iterations - if (MultiPV == 1 && Iteration >= 6 && abs(ValueByIteration[Iteration - 1]) < VALUE_KNOWN_WIN) + if (MultiPV == 1 && depth >= 5 && abs(bestValues[depth - 1]) < VALUE_KNOWN_WIN) { - int prevDelta1 = ValueByIteration[Iteration - 1] - ValueByIteration[Iteration - 2]; - int prevDelta2 = ValueByIteration[Iteration - 2] - ValueByIteration[Iteration - 3]; + int prevDelta1 = bestValues[depth - 1] - bestValues[depth - 2]; + int prevDelta2 = bestValues[depth - 2] - bestValues[depth - 3]; - AspirationDelta = Max(abs(prevDelta1) + abs(prevDelta2) / 2, 16); - AspirationDelta = (AspirationDelta + 7) / 8 * 8; // Round to match grainSize + aspirationDelta = Min(Max(abs(prevDelta1) + abs(prevDelta2) / 2, 16), 24); + aspirationDelta = (aspirationDelta + 7) / 8 * 8; // Round to match grainSize - alpha = Max(ValueByIteration[Iteration - 1] - AspirationDelta, -VALUE_INFINITE); - beta = Min(ValueByIteration[Iteration - 1] + AspirationDelta, VALUE_INFINITE); + alpha = Max(bestValues[depth - 1] - aspirationDelta, -VALUE_INFINITE); + beta = Min(bestValues[depth - 1] + aspirationDelta, VALUE_INFINITE); } - depth = (Iteration - 2) * ONE_PLY + InitialDepth; - - // Search to the current depth, rml is updated and sorted - value = root_search(pos, ss, alpha, beta, depth, rml); - - if (StopRequest) - break; // Value cannot be trusted. Break out immediately! - - //Save info about search result - ValueByIteration[Iteration] = value; - - // Drop the easy move if differs from the new best move - if (rml[0].pv[0] != EasyMove) - EasyMove = MOVE_NONE; - - if (UseTimeManagement) - { - // Time to stop? - bool stopSearch = false; - - // Stop search early if there is only a single legal move, - // we search up to Iteration 6 anyway to get a proper score. - if (Iteration >= 6 && rml.size() == 1) - stopSearch = true; - - // Stop search early when the last two iterations returned a mate score - if ( Iteration >= 6 - && abs(ValueByIteration[Iteration]) >= abs(VALUE_MATE) - 100 - && abs(ValueByIteration[Iteration-1]) >= abs(VALUE_MATE) - 100) - stopSearch = true; - - // Stop search early if one move seems to be much better than the others - if ( Iteration >= 8 - && EasyMove == rml[0].pv[0] - && ( ( 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))) - stopSearch = true; - - // Add some extra time if the best move has changed during the last two iterations - if (Iteration > 5 && Iteration <= 50) - TimeMgr.pv_instability(BestMoveChangesByIteration[Iteration], - BestMoveChangesByIteration[Iteration-1]); - - // 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) - stopSearch = true; - - if (stopSearch) - { - if (Pondering) - StopOnPonderhit = true; - else - break; - } - } - - if (MaxDepth && Iteration >= MaxDepth) - break; - } - - *ponderMove = rml[0].pv[1]; - return rml[0].pv[0]; - } - - - // root_search() is the function which searches the root node. It is - // similar to search_pv except that it prints some information to the - // standard output and handles the fail low/high loops. - - Value root_search(Position& pos, SearchStack* ss, Value alpha, - Value beta, Depth depth, RootMoveList& rml) { - StateInfo st; - CheckInfo ci(pos); - int64_t nodes; - Move move; - Depth ext, newDepth; - Value value, oldAlpha; - bool isCheck, moveIsCheck, captureOrPromotion, dangerous; - int researchCountFH, researchCountFL; - - researchCountFH = researchCountFL = 0; - oldAlpha = alpha; - isCheck = pos.is_check(); - - // Step 1. Initialize node (polling is omitted at root) - ss->currentMove = ss->bestMove = MOVE_NONE; - - // Step 2. Check for aborted search (omitted at root) - // Step 3. Mate distance pruning (omitted at root) - // Step 4. Transposition table lookup (omitted at root) + // 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); - // Step 5. Evaluate the position statically - // At root we do this only to get reference value for child nodes - ss->evalMargin = VALUE_NONE; - ss->eval = isCheck ? VALUE_NONE : evaluate(pos, ss->evalMargin); + // 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); - // Step 6. Razoring (omitted at root) - // Step 7. Static null move pruning (omitted at root) - // Step 8. Null move search with verification search (omitted at root) - // Step 9. Internal iterative deepening (omitted at root) - - // Step extra. Fail low loop - // We start with small aspiration window and in case of fail low, we research - // with bigger window until we are not failing low anymore. - while (1) - { - // Sort the moves before to (re)search - rml.set_non_pv_scores(pos); - rml.sort(); - - // Step 10. Loop through all moves in the root move list - for (int i = 0; i < (int)rml.size() && !StopRequest; i++) - { - // This is used by time management - FirstRootMove = (i == 0); + // Value cannot be trusted. Break out immediately! + if (StopRequest) + break; - // Save the current node count before the move is searched - nodes = pos.nodes_searched(); + assert(value >= alpha); - // 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) + // In case of failing high/low increase aspiration window and research, + // otherwise exit the fail high/low loop. + if (value >= beta) { - SendSearchedNodes = false; - cout << "info nodes " << nodes - << " nps " << nps(pos) - << " time " << current_search_time() << endl; + beta = Min(beta + aspirationDelta, VALUE_INFINITE); + aspirationDelta += aspirationDelta / 2; } - - // Pick the next root move, and print the move and the move number to - // the standard output. - move = ss->currentMove = rml[i].pv[0]; - - if (current_search_time() >= 1000) - cout << "info currmove " << move - << " currmovenumber " << i + 1 << endl; - - moveIsCheck = pos.move_is_check(move); - captureOrPromotion = pos.move_is_capture_or_promotion(move); - - // Step 11. Decide the new search depth - ext = extension(pos, move, captureOrPromotion, moveIsCheck, false, false, &dangerous); - newDepth = depth + ext; - - // Step 12. Futility pruning (omitted at root) - - // Step extra. Fail high loop - // If move fails high, we research with bigger window until we are not failing - // high anymore. - value = -VALUE_INFINITE; - - while (1) + else if (value <= alpha) { - // Step 13. Make the move - pos.do_move(move, st, ci, moveIsCheck); - - // Step extra. pv search - // We do pv search for first moves (i < MultiPV) - // and for fail high research (value > alpha) - if (i < MultiPV || value > alpha) - { - // Aspiration window is disabled in multi-pv case - if (MultiPV > 1) - alpha = -VALUE_INFINITE; - - // Full depth PV search, done on first move or after a fail high - value = -search(pos, ss+1, -beta, -alpha, newDepth, 1); - } - else - { - // Step 14. Reduced search - // if the move fails high will be re-searched at full depth - bool doFullDepthSearch = true; - - if ( depth >= 3 * ONE_PLY - && !dangerous - && !captureOrPromotion - && !move_is_castle(move)) - { - ss->reduction = reduction(depth, i - MultiPV + 2); - if (ss->reduction) - { - assert(newDepth-ss->reduction >= ONE_PLY); - - // Reduced depth non-pv search using alpha as upperbound - value = -search(pos, ss+1, -(alpha+1), -alpha, newDepth-ss->reduction, 1); - doFullDepthSearch = (value > alpha); - } - ss->reduction = DEPTH_ZERO; // Restore original reduction - } - - // Step 15. Full depth search - if (doFullDepthSearch) - { - // Full depth non-pv search using alpha as upperbound - value = -search(pos, ss+1, -(alpha+1), -alpha, newDepth, 1); - - // If we are above alpha then research at same depth but as PV - // to get a correct score or eventually a fail high above beta. - if (value > alpha) - value = -search(pos, ss+1, -beta, -alpha, newDepth, 1); - } - } - - // Step 16. Undo move - pos.undo_move(move); - - // Can we exit fail high loop ? - if (StopRequest || value < beta) - break; - - // We are failing high and going to do a research. It's important to update - // the score before research in case we run out of time while researching. - ss->bestMove = move; - rml[i].pv_score = value; - rml[i].extract_pv_from_tt(pos); - - // Inform GUI that PV has changed - cout << rml[i].pv_info_to_uci(pos, alpha, beta) << endl; - - // Prepare for a research after a fail high, each time with a wider window - beta = Min(beta + AspirationDelta * (1 << researchCountFH), VALUE_INFINITE); - researchCountFH++; - - } // End of fail high loop - - // Finished searching the move. If AbortSearch 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 - rml[i].nodes += pos.nodes_searched() - nodes; - - assert(value >= -VALUE_INFINITE && value <= VALUE_INFINITE); - assert(value < beta); + AspirationFailLow = true; + StopOnPonderhit = false; - // Step 17. Check for new best move - if (value <= alpha && i >= MultiPV) - rml[i].pv_score = -VALUE_INFINITE; + alpha = Max(alpha - aspirationDelta, -VALUE_INFINITE); + aspirationDelta += aspirationDelta / 2; + } else - { - // PV move or new best move! - - // Update PV - ss->bestMove = move; - rml[i].pv_score = value; - rml[i].extract_pv_from_tt(pos); + break; - // We record how often the best move has been changed in each - // iteration. This information is used for time managment: When - // the best move changes frequently, we allocate some more time. - if (MultiPV == 1 && i > 0) - BestMoveChangesByIteration[Iteration]++; + } while (abs(value) < VALUE_KNOWN_WIN); - // Inform GUI that PV has changed, in case of multi-pv UCI protocol - // requires we send all the PV lines properly sorted. - rml.sort_multipv(i); + // Collect info about search result + bestMove = Rml[0].pv[0]; + *ponderMove = Rml[0].pv[1]; + bestValues[depth] = value; + bestMoveChanges[depth] = Rml.bestMoveChanges; - for (int j = 0; j < Min(MultiPV, (int)rml.size()); j++) - cout << rml[j].pv_info_to_uci(pos, alpha, beta, j) << endl; + // Do we need to pick now the best and the ponder moves ? + if (SkillLevelEnabled && depth == 1 + SkillLevel) + do_skill_level(&skillBest, &skillPonder); - // Update alpha. In multi-pv we don't use aspiration window - if (MultiPV == 1) - { - // Raise alpha to setup proper non-pv search upper bound - if (value > alpha) - alpha = value; - } - else // Set alpha equal to minimum score among the PV lines - alpha = rml[Min(i, MultiPV - 1)].pv_score; + // Retrieve max searched depth among threads + selDepth = 0; + for (int i = 0; i < Threads.size(); i++) + if (Threads[i].maxPly > selDepth) + selDepth = Threads[i].maxPly; - } // PV move or new best move + // 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; - assert(alpha >= oldAlpha); + if (LogFile.is_open()) + LogFile << pretty_pv(pos, depth, value, current_search_time(), Rml[0].pv) << endl; - AspirationFailLow = (alpha == oldAlpha); + // 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; - if (AspirationFailLow && StopOnPonderhit) - StopOnPonderhit = false; + // Check for some early stop condition + if (!StopRequest && Limits.useTimeManagement()) + { + // Stop search early when the last two iterations returned a mate score + if ( depth >= 5 + && abs(bestValues[depth]) >= VALUE_MATE_IN_PLY_MAX + && abs(bestValues[depth - 1]) >= VALUE_MATE_IN_PLY_MAX) + StopRequest = true; - } // Root moves loop + // Stop search early if one move seems to be much better than the + // others or if there is only a single legal move. Also in the latter + // case we search up to some depth anyway to get a proper score. + if ( depth >= 7 + && easyMove == bestMove + && ( Rml.size() == 1 + ||( Rml[0].nodes > (pos.nodes_searched() * 85) / 100 + && current_search_time() > TimeMgr.available_time() / 16) + ||( Rml[0].nodes > (pos.nodes_searched() * 98) / 100 + && current_search_time() > TimeMgr.available_time() / 32))) + StopRequest = true; - // Can we exit fail low loop ? - if (StopRequest || !AspirationFailLow) - break; + // Take in account some extra time if the best move has changed + if (depth > 4 && depth < 50) + TimeMgr.pv_instability(bestMoveChanges[depth], bestMoveChanges[depth - 1]); - // Prepare for a research after a fail low, each time with a wider window - oldAlpha = alpha = Max(alpha - AspirationDelta * (1 << researchCountFL), -VALUE_INFINITE); - researchCountFL++; + // Stop search if most of available time is already consumed. We probably don't + // have enough time to search the first move at the next iteration anyway. + if (current_search_time() > (TimeMgr.available_time() * 62) / 100) + StopRequest = true; - } // Fail low loop + // If we are allowed to ponder do not stop the search now but keep pondering + if (StopRequest && Limits.ponder) + { + StopRequest = false; + StopOnPonderhit = true; + } + } + } - // Sort the moves before to return - rml.sort(); + // When using skills overwrite best and ponder moves with the sub-optimal ones + if (SkillLevelEnabled) + { + if (skillBest == MOVE_NONE) // Still unassigned ? + do_skill_level(&skillBest, &skillPonder); - // Write PV lines to transposition table, in case the relevant entries - // have been overwritten during the search. - for (int i = 0; i < MultiPV; i++) - rml[i].insert_pv_in_tt(pos); + bestMove = skillBest; + *ponderMove = skillPonder; + } - return alpha; + return bestMove; } @@ -917,16 +663,16 @@ 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, int ply) { + template + Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth) { assert(alpha >= -VALUE_INFINITE && alpha <= VALUE_INFINITE); assert(beta > alpha && beta <= VALUE_INFINITE); assert(PvNode || alpha == beta - 1); - assert(ply > 0 && ply < PLY_MAX); - 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; Key posKey; @@ -935,14 +681,19 @@ namespace { ValueType vt; Value bestValue, value, oldAlpha; Value refinedValue, nullValue, futilityBase, futilityValueScaled; // Non-PV specific - bool isCheck, singleEvasion, singularExtensionNode, moveIsCheck, captureOrPromotion, dangerous; - bool mateThreat = false; - int moveCount = 0; + bool isPvMove, isCheck, singularExtensionNode, moveIsCheck, captureOrPromotion, dangerous, isBadCap; + int moveCount = 0, playedMoveCount = 0; int threadID = pos.thread(); SplitPoint* sp = NULL; + refinedValue = bestValue = value = -VALUE_INFINITE; oldAlpha = alpha; isCheck = pos.is_check(); + ss->ply = (ss-1)->ply + 1; + + // Used to send selDepth info to GUI + if (PvNode && Threads[threadID].maxPly < ss->ply) + Threads[threadID].maxPly = ss->ply; if (SpNode) { @@ -950,13 +701,14 @@ namespace { tte = NULL; ttMove = excludedMove = MOVE_NONE; threatMove = sp->threatMove; - mateThreat = sp->mateThreat; goto split_point_start; } - else {} // Hack to fix icc's "statement is unreachable" warning + else if (Root) + bestValue = alpha; // Step 1. Initialize node and poll. Polling can abort search - ss->currentMove = ss->bestMove = threatMove = MOVE_NONE; + 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) @@ -966,44 +718,41 @@ namespace { } // Step 2. Check for aborted search and immediate draw - if ( StopRequest - || ThreadsMgr.cutoff_at_splitpoint(threadID) - || pos.is_draw() - || ply >= PLY_MAX - 1) + if (( StopRequest + || Threads[threadID].cutoff_occurred() + || pos.is_draw() + || ss->ply > PLY_MAX) && !Root) return VALUE_DRAW; // Step 3. Mate distance pruning - alpha = Max(value_mated_in(ply), alpha); - beta = Min(value_mate_in(ply+1), beta); + alpha = Max(value_mated_in(ss->ply), alpha); + beta = 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 exists. + // 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; - // At PV nodes, we don't use the TT for pruning, but only for move ordering. - // This is to avoid problems in the following areas: - // - // * Repetition draw detection - // * Fifty move rule detection - // * Searching for a mate - // * Printing of full PV line - if (!PvNode && tte && ok_to_use_TT(tte, depth, beta, ply)) + // 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))) { TT.refresh(tte); ss->bestMove = ttMove; // Can be MOVE_NONE - return value_from_tt(tte->value(), ply); + return value_from_tt(tte->value(), ss->ply); } - // Step 5. Evaluate the position statically and - // update gain statistics of parent move. + // Step 5. Evaluate the position statically and update parent's gain statistics if (isCheck) ss->eval = ss->evalMargin = VALUE_NONE; else if (tte) @@ -1012,7 +761,7 @@ namespace { ss->eval = tte->static_value(); ss->evalMargin = tte->static_value_margin(); - refinedValue = refine_eval(tte, ss->eval, ply); + refinedValue = refine_eval(tte, ss->eval, ss->ply); } else { @@ -1027,13 +776,13 @@ namespace { if ( !PvNode && depth < RazorDepth && !isCheck - && refinedValue < beta - razor_margin(depth) + && refinedValue + razor_margin(depth) < beta && ttMove == MOVE_NONE - && !value_is_mate(beta) + && abs(beta) < VALUE_MATE_IN_PLY_MAX && !pos.has_pawn_on_7th(pos.side_to_move())) { Value rbeta = beta - razor_margin(depth); - Value v = qsearch(pos, ss, rbeta-1, rbeta, DEPTH_ZERO, ply); + Value v = qsearch(pos, ss, rbeta-1, rbeta, DEPTH_ZERO); if (v < rbeta) // Logically we should return (v + razor_margin(depth)), but // surprisingly this did slightly weaker in tests. @@ -1047,8 +796,8 @@ namespace { && !ss->skipNullMove && depth < RazorDepth && !isCheck - && refinedValue >= beta + futility_margin(depth, 0) - && !value_is_mate(beta) + && refinedValue - futility_margin(depth, 0) >= beta + && abs(beta) < VALUE_MATE_IN_PLY_MAX && pos.non_pawn_material(pos.side_to_move())) return refinedValue - futility_margin(depth, 0); @@ -1058,7 +807,7 @@ namespace { && depth > ONE_PLY && !isCheck && refinedValue >= beta - && !value_is_mate(beta) + && abs(beta) < VALUE_MATE_IN_PLY_MAX && pos.non_pawn_material(pos.side_to_move())) { ss->currentMove = MOVE_NULL; @@ -1067,19 +816,19 @@ namespace { int R = 3 + (depth >= 5 * ONE_PLY ? depth / 8 : 0); // Null move dynamic reduction based on value - if (refinedValue - beta > PawnValueMidgame) + if (refinedValue - PawnValueMidgame > beta) R++; pos.do_null_move(st); (ss+1)->skipNullMove = true; - nullValue = -search(pos, ss+1, -beta, -alpha, depth-R*ONE_PLY, ply+1); + nullValue = -search(pos, ss+1, -beta, -alpha, depth-R*ONE_PLY); (ss+1)->skipNullMove = false; pos.undo_null_move(); if (nullValue >= beta) { // Do not return unproven mate scores - if (nullValue >= value_mate_in(PLY_MAX)) + if (nullValue >= VALUE_MATE_IN_PLY_MAX) nullValue = beta; if (depth < 6 * ONE_PLY) @@ -1087,7 +836,7 @@ namespace { // Do verification search at high depths ss->skipNullMove = true; - Value v = search(pos, ss, alpha, beta, depth-R*ONE_PLY, ply); + Value v = search(pos, ss, alpha, beta, depth-R*ONE_PLY); ss->skipNullMove = false; if (v >= beta) @@ -1101,10 +850,8 @@ namespace { // move which was reduced. If a connection is found, return a fail // low score (which will cause the reduced move to fail high in the // parent node, which will trigger a re-search with full depth). - if (nullValue == value_mated_in(ply + 2)) - mateThreat = true; - threatMove = (ss+1)->bestMove; + if ( depth < ThreatDepth && (ss-1)->reduction && threatMove != MOVE_NONE @@ -1114,35 +861,29 @@ namespace { } // Step 9. Internal iterative deepening - if ( depth >= IIDDepth[PvNode] - && ttMove == MOVE_NONE - && (PvNode || (!isCheck && ss->eval >= beta - IIDMargin))) + if ( depth >= IIDDepth[PvNode] + && ttMove == MOVE_NONE + && (PvNode || (!isCheck && ss->eval + IIDMargin >= beta))) { Depth d = (PvNode ? depth - 2 * ONE_PLY : depth / 2); ss->skipNullMove = true; - search(pos, ss, alpha, beta, d, ply); + search(pos, ss, alpha, beta, d); ss->skipNullMove = false; ttMove = ss->bestMove; tte = TT.retrieve(posKey); } - // Expensive mate threat detection (only for PV nodes) - if (PvNode) - mateThreat = pos.has_mate_threat(); - split_point_start: // At split points actual search starts from here // Initialize a MovePicker object for the current position - // FIXME currently MovePicker() c'tor is needless called also in SplitPoint - MovePicker mpBase(pos, ttMove, depth, H, ss, (PvNode ? -VALUE_INFINITE : beta)); - MovePicker& mp = SpNode ? *sp->mp : mpBase; + MovePickerExt mp(pos, ttMove, depth, H, ss, (PvNode ? -VALUE_INFINITE : beta)); CheckInfo ci(pos); ss->bestMove = MOVE_NONE; - singleEvasion = !SpNode && isCheck && mp.number_of_evasions() == 1; futilityBase = ss->eval + ss->evalMargin; - singularExtensionNode = !SpNode + singularExtensionNode = !Root + && !SpNode && depth >= SingularExtensionDepth[PvNode] && tte && tte->move() @@ -1159,7 +900,7 @@ split_point_start: // At split points actual search starts from here // Loop through all 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)) + && !Threads[threadID].cutoff_occurred()) { assert(move_is_ok(move)); @@ -1171,34 +912,58 @@ split_point_start: // At split points actual search starts from here else if (move == excludedMove) continue; else - movesSearched[moveCount++] = move; + moveCount++; + + if (Root) + { + // This is used by time management + FirstRootMove = (moveCount == 1); + + // Save the current node count before the move is searched + 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; + } + + // 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); // Step 11. Decide the new search depth - ext = extension(pos, move, captureOrPromotion, moveIsCheck, singleEvasion, mateThreat, &dangerous); + ext = extension(pos, move, captureOrPromotion, moveIsCheck, &dangerous); - // 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 is singular and should be extended. - // To verify this we do a reduced search on all the other moves but the ttMove, if result is - // lower then ttValue minus a margin then we extend ttMove. + // 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 + // is singular and should be extended. To verify this we do a reduced search + // 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) { - Value ttValue = value_from_tt(tte->value(), ply); + Value ttValue = value_from_tt(tte->value(), ss->ply); if (abs(ttValue) < VALUE_KNOWN_WIN) { - Value b = ttValue - SingularExtensionMargin; + Value rBeta = ttValue - int(depth); ss->excludedMove = move; ss->skipNullMove = true; - Value v = search(pos, ss, b - 1, b, depth / 2, ply); + Value v = search(pos, ss, rBeta - 1, rBeta, depth / 2); ss->skipNullMove = false; ss->excludedMove = MOVE_NONE; ss->bestMove = MOVE_NONE; - if (v < b) + if (v < rBeta) ext = ONE_PLY; } } @@ -1217,8 +982,8 @@ split_point_start: // At split points actual search starts from here { // 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)) + && bestValue > VALUE_MATED_IN_PLY_MAX) // FIXME bestValue is racy { if (SpNode) lock_grab(&(sp->lock)); @@ -1249,7 +1014,7 @@ split_point_start: // At split points actual search starts from here // Prune moves with negative SEE at low depths if ( predictedDepth < 2 * ONE_PLY - && bestValue > value_mated_in(PLY_MAX) + && bestValue > VALUE_MATED_IN_PLY_MAX && pos.see_sign(move) < 0) { if (SpNode) @@ -1259,18 +1024,38 @@ 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); + if (!SpNode && !captureOrPromotion) + movesSearched[playedMoveCount++] = move; + // Step extra. pv search (only in PV nodes) // The first move in list is the expected PV - if (PvNode && moveCount == 1) - value = -search(pos, ss+1, -beta, -alpha, newDepth, ply+1); + if (isPvMove) + { + // Aspiration window is disabled in multi-pv case + if (Root && MultiPV > 1) + alpha = -VALUE_INFINITE; + + value = -search(pos, ss+1, -beta, -alpha, newDepth); + } else { // Step 14. Reduced depth search // If the move fails high will be re-searched at full depth. bool doFullDepthSearch = true; + alpha = SpNode ? sp->alpha : alpha; if ( depth >= 3 * ONE_PLY && !captureOrPromotion @@ -1280,29 +1065,40 @@ split_point_start: // At split points actual search starts from here && 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, ply+1); + value = -search(pos, ss+1, -(alpha+1), -alpha, d); doFullDepthSearch = (value > alpha); } ss->reduction = DEPTH_ZERO; // Restore original reduction } + // 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 + } + // Step 15. Full depth search if (doFullDepthSearch) { alpha = SpNode ? sp->alpha : alpha; - value = -search(pos, ss+1, -(alpha+1), -alpha, newDepth, ply+1); + 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 && value < beta) - value = -search(pos, ss+1, -beta, -alpha, newDepth, ply+1); + if (PvNode && value > alpha && (Root || value < beta)) + value = -search(pos, ss+1, -beta, -alpha, newDepth); } } @@ -1319,14 +1115,14 @@ split_point_start: // At split points actual search starts from here alpha = sp->alpha; } - if (value > bestValue && !(SpNode && ThreadsMgr.cutoff_at_splitpoint(threadID))) + if (value > bestValue && !(SpNode && Threads[threadID].cutoff_occurred())) { bestValue = value; if (SpNode) sp->bestValue = value; - if (value > alpha) + if (!Root && value > alpha) { if (PvNode && value < beta) // We want always alpha < beta { @@ -1336,29 +1132,69 @@ split_point_start: // At split points actual search starts from here sp->alpha = value; } else if (SpNode) - sp->betaCutoff = true; + sp->is_betaCutoff = true; - if (value == value_mate_in(ply + 1)) + if (value == value_mate_in(ss->ply + 1)) ss->mateKiller = move; ss->bestMove = move; if (SpNode) - sp->parentSstack->bestMove = move; + 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 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; + + // 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); + + // 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; + } + else + mp.rm->pv_score = -VALUE_INFINITE; + + } // Root + // Step 18. Check for split - if ( !SpNode - && depth >= ThreadsMgr.min_split_depth() - && ThreadsMgr.active_threads() > 1 + if ( !Root + && !SpNode + && depth >= Threads.min_split_depth() && bestValue < beta - && ThreadsMgr.available_thread_exists(threadID) + && Threads.available_slave_exists(threadID) && !StopRequest - && !ThreadsMgr.cutoff_at_splitpoint(threadID) - && Iteration <= 99) - ThreadsMgr.split(pos, ss, ply, &alpha, beta, &bestValue, depth, - threatMove, mateThreat, moveCount, &mp, PvNode); + && !Threads[threadID].cutoff_occurred()) + Threads.split(pos, ss, &alpha, beta, &bestValue, depth, + threatMove, moveCount, &mp, PvNode); } // Step 19. Check for mate and stalemate @@ -1366,32 +1202,36 @@ split_point_start: // At split points actual search starts from here // 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(ply) : VALUE_DRAW; + 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)) + if (!SpNode && !StopRequest && !Threads[threadID].cutoff_occurred()) { move = bestValue <= oldAlpha ? MOVE_NONE : ss->bestMove; vt = bestValue <= oldAlpha ? VALUE_TYPE_UPPER : bestValue >= beta ? VALUE_TYPE_LOWER : VALUE_TYPE_EXACT; - TT.store(posKey, value_to_tt(bestValue, ply), vt, depth, move, ss->eval, ss->evalMargin); + 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 if ( bestValue >= beta && !pos.move_is_capture_or_promotion(move)) { - update_history(pos, move, depth, movesSearched, moveCount); - update_killers(move, ss); + if (move != ss->killers[0]) + { + ss->killers[1] = ss->killers[0]; + ss->killers[0] = move; + } + update_history(pos, move, depth, movesSearched, playedMoveCount); } } if (SpNode) { // Here we have the lock still grabbed - sp->slaves[threadID] = 0; + sp->is_slave[threadID] = false; sp->nodes += pos.nodes_searched(); lock_release(&(sp->lock)); } @@ -1406,14 +1246,13 @@ split_point_start: // At split points actual search starts from here // less than ONE_PLY). template - Value qsearch(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth, int ply) { + Value qsearch(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth) { assert(alpha >= -VALUE_INFINITE && alpha <= VALUE_INFINITE); assert(beta >= -VALUE_INFINITE && beta <= VALUE_INFINITE); assert(PvNode || alpha == beta - 1); assert(depth <= 0); - assert(ply > 0 && ply < PLY_MAX); - assert(pos.thread() >= 0 && pos.thread() < ThreadsMgr.active_threads()); + assert(pos.thread() >= 0 && pos.thread() < Threads.size()); StateInfo st; Move ttMove, move; @@ -1424,9 +1263,10 @@ split_point_start: // At split points actual search starts from here 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 (pos.is_draw() || ply >= PLY_MAX - 1) + if (ss->ply > PLY_MAX || pos.is_draw()) return VALUE_DRAW; // Decide whether or not to include checks, this fixes also the type of @@ -1440,10 +1280,10 @@ split_point_start: // At split points actual search starts from here tte = TT.retrieve(pos.get_key()); ttMove = (tte ? tte->move() : MOVE_NONE); - if (!PvNode && tte && ok_to_use_TT(tte, ttDepth, beta, ply)) + if (!PvNode && tte && ok_to_use_TT(tte, ttDepth, beta, ss->ply)) { ss->bestMove = ttMove; // Can be MOVE_NONE - return value_from_tt(tte->value(), ply); + return value_from_tt(tte->value(), ss->ply); } // Evaluate the position statically @@ -1471,7 +1311,7 @@ split_point_start: // At split points actual search starts from here if (bestValue >= beta) { if (!tte) - TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, DEPTH_NONE, MOVE_NONE, ss->eval, evalMargin); + TT.store(pos.get_key(), value_to_tt(bestValue, ss->ply), VALUE_TYPE_LOWER, DEPTH_NONE, MOVE_NONE, ss->eval, evalMargin); return bestValue; } @@ -1518,11 +1358,17 @@ split_point_start: // At split points actual search starts from here bestValue = futilityValue; continue; } + + // Prune moves with negative or equal SEE + if ( futilityBase < beta + && depth < DEPTH_ZERO + && pos.see(move) <= 0) + continue; } // Detect non-capture evasions that are candidate to be pruned evasionPrunable = isCheck - && bestValue > value_mated_in(PLY_MAX) + && bestValue > VALUE_MATED_IN_PLY_MAX && !pos.move_is_capture(move) && !pos.can_castle(pos.side_to_move()); @@ -1554,7 +1400,7 @@ split_point_start: // At split points actual search starts from here // Make and search the move pos.do_move(move, st, ci, moveIsCheck); - value = -qsearch(pos, ss+1, -beta, -alpha, depth-ONE_PLY, ply+1); + value = -qsearch(pos, ss+1, -beta, -alpha, depth-ONE_PLY); pos.undo_move(move); assert(value > -VALUE_INFINITE && value < VALUE_INFINITE); @@ -1574,11 +1420,11 @@ split_point_start: // At split points actual search starts from here // 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) - return value_mated_in(ply); + 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, ply), vt, ttDepth, ss->bestMove, ss->eval, evalMargin); + TT.store(pos.get_key(), value_to_tt(bestValue, ss->ply), vt, ttDepth, ss->bestMove, ss->eval, evalMargin); assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE); @@ -1696,28 +1542,16 @@ split_point_start: // At split points actual search starts from here } - // value_is_mate() checks if the given value is a mate one eventually - // compensated for the ply. - - bool value_is_mate(Value value) { - - assert(abs(value) <= VALUE_INFINITE); - - return value <= value_mated_in(PLY_MAX) - || value >= value_mate_in(PLY_MAX); - } - - // 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. Value value_to_tt(Value v, int ply) { - if (v >= value_mate_in(PLY_MAX)) + if (v >= VALUE_MATE_IN_PLY_MAX) return v + ply; - if (v <= value_mated_in(PLY_MAX)) + if (v <= VALUE_MATED_IN_PLY_MAX) return v - ply; return v; @@ -1729,10 +1563,10 @@ split_point_start: // At split points actual search starts from here Value value_from_tt(Value v, int ply) { - if (v >= value_mate_in(PLY_MAX)) + if (v >= VALUE_MATE_IN_PLY_MAX) return v - ply; - if (v <= value_mated_in(PLY_MAX)) + if (v <= VALUE_MATED_IN_PLY_MAX) return v + ply; return v; @@ -1746,25 +1580,16 @@ split_point_start: // At split points actual search starts from here // 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 singleEvasion, bool mateThreat, bool* dangerous) { + Depth extension(const Position& pos, Move m, bool captureOrPromotion, + bool moveIsCheck, bool* dangerous) { assert(m != MOVE_NONE); Depth result = DEPTH_ZERO; - *dangerous = moveIsCheck | singleEvasion | mateThreat; + *dangerous = moveIsCheck; - if (*dangerous) - { - if (moveIsCheck && pos.see_sign(m) >= 0) - result += CheckExtension[PvNode]; - - if (singleEvasion) - result += SingleEvasionExtension[PvNode]; - - if (mateThreat) - result += MateThreatExtension[PvNode]; - } + if (moveIsCheck && pos.see_sign(m) >= 0) + result += CheckExtension[PvNode]; if (pos.type_of_piece_on(move_from(m)) == PAWN) { @@ -1785,28 +1610,18 @@ split_point_start: // At split points actual search starts from here && 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_promotion(m) - && !move_is_ep(m)) + && !move_is_special(m)) { result += PawnEndgameExtension[PvNode]; *dangerous = true; } - if ( PvNode - && captureOrPromotion - && pos.type_of_piece_on(move_to(m)) != PAWN - && pos.see_sign(m) >= 0) - { - result += ONE_PLY / 2; - *dangerous = true; - } - return Min(result, ONE_PLY); } // connected_threat() tests whether it is safe to forward prune a move or if - // is somehow coonected to the threat move returned by null search. + // is somehow connected to the threat move returned by null search. bool connected_threat(const Position& pos, Move m, Move threat) { @@ -1828,7 +1643,7 @@ split_point_start: // At split points actual search starts from here return true; // Case 2: If the threatened piece has value less than or equal to the - // value of the threatening piece, don't prune move which defend it. + // 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) @@ -1854,8 +1669,8 @@ split_point_start: // At split points actual search starts from here Value v = value_from_tt(tte->value(), ply); return ( tte->depth() >= depth - || v >= Max(value_mate_in(PLY_MAX), beta) - || v < Min(value_mated_in(PLY_MAX), beta)) + || v >= Max(VALUE_MATE_IN_PLY_MAX, beta) + || v < Min(VALUE_MATED_IN_PLY_MAX, beta)) && ( ((tte->type() & VALUE_TYPE_LOWER) && v >= beta) || ((tte->type() & VALUE_TYPE_UPPER) && v < beta)); @@ -1885,8 +1700,9 @@ split_point_start: // At split points actual search starts from here void update_history(const Position& pos, Move move, Depth depth, Move movesSearched[], int moveCount) { Move m; + Value bonus = Value(int(depth) * int(depth)); - H.success(pos.piece_on(move_from(move)), move_to(move), depth); + H.update(pos.piece_on(move_from(move)), move_to(move), bonus); for (int i = 0; i < moveCount - 1; i++) { @@ -1894,25 +1710,11 @@ split_point_start: // At split points actual search starts from here assert(m != move); - if (!pos.move_is_capture_or_promotion(m)) - H.failure(pos.piece_on(move_from(m)), move_to(m), depth); + H.update(pos.piece_on(move_from(m)), move_to(m), -bonus); } } - // update_killers() add a good move that produced a beta-cutoff - // among the killer moves of that ply. - - void update_killers(Move m, SearchStack* ss) { - - if (m == ss->killers[0]) - return; - - ss->killers[1] = ss->killers[0]; - ss->killers[0] = m; - } - - // update_gains() updates the gains table of a non-capture move given // the static position evaluation before and after the move. @@ -1923,25 +1725,21 @@ split_point_start: // At split points actual search starts from here && after != VALUE_NONE && pos.captured_piece_type() == PIECE_TYPE_NONE && !move_is_special(m)) - H.set_gain(pos.piece_on(move_to(m)), move_to(m), -(before + after)); + H.update_gain(pos.piece_on(move_to(m)), move_to(m), -(before + after)); } - // init_ss_array() does a fast reset of the first entries of a SearchStack - // array and of all the excludedMove and skipNullMove entries. + // current_search_time() returns the number of milliseconds which have passed + // since the beginning of the current search. - void init_ss_array(SearchStack* ss, int size) { + int current_search_time(int set) { - for (int i = 0; i < size; i++, ss++) - { - ss->excludedMove = MOVE_NONE; - ss->skipNullMove = false; - ss->reduction = DEPTH_ZERO; - ss->sp = NULL; + static int searchStartTime; - if (i < 3) - ss->killers[0] = ss->killers[1] = ss->mateKiller = MOVE_NONE; - } + if (set) + searchStartTime = set; + + return get_system_time() - searchStartTime; } @@ -1957,29 +1755,27 @@ split_point_start: // At split points actual search starts from here std::stringstream s; if (abs(v) < VALUE_MATE - PLY_MAX * ONE_PLY) - s << "cp " << int(v) * 100 / int(PawnValueMidgame); // Scale to centipawns + s << "cp " << int(v) * 100 / int(PawnValueMidgame); // Scale to centipawns else - s << "mate " << (v > 0 ? (VALUE_MATE - v + 1) / 2 : -(VALUE_MATE + v) / 2 ); + s << "mate " << (v > 0 ? VALUE_MATE - v + 1 : -VALUE_MATE - v) / 2; return s.str(); } - // current_search_time() returns the number of milliseconds which have passed - // since the beginning of the current search. - - int current_search_time() { - - return get_system_time() - SearchStartTime; - } + // 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) { - // nps() computes the current nodes/second count + std::stringstream s; + int t = current_search_time(); - int nps(const Position& pos) { + s << " nodes " << nodes + << " nps " << (t > 0 ? int(nodes * 1000 / t) : 0) + << " time " << t; - int t = current_search_time(); - return (t > 0 ? int((pos.nodes_searched() * 1000) / t) : 0); + return s.str(); } @@ -1993,18 +1789,15 @@ split_point_start: // At split points actual search starts from here int t = current_search_time(); // Poll for input - if (data_available()) + if (input_available()) { // We are line oriented, don't read single chars std::string command; - if (!std::getline(std::cin, command)) - command = "quit"; - - if (command == "quit") + if (!std::getline(std::cin, command) || command == "quit") { // Quit the program as soon as possible - Pondering = false; + Limits.ponder = false; QuitRequest = StopRequest = true; return; } @@ -2012,7 +1805,7 @@ split_point_start: // At split points actual search starts from here { // Stop calculating as soon as possible, but still send the "bestmove" // and possibly the "ponder" token when finishing the search. - Pondering = false; + Limits.ponder = false; StopRequest = true; } else if (command == "ponderhit") @@ -2020,7 +1813,7 @@ split_point_start: // At split points actual search starts from here // 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. - Pondering = false; + Limits.ponder = false; if (StopOnPonderhit) StopRequest = true; @@ -2040,18 +1833,15 @@ split_point_start: // At split points actual search starts from here { lastInfoTime = t; - if (dbg_show_mean) - dbg_print_mean(); - - if (dbg_show_hit_rate) - dbg_print_hit_rate(); + dbg_print_mean(); + dbg_print_hit_rate(); // Send info on searched nodes as soon as we return to root SendSearchedNodes = true; } // Should we stop the search? - if (Pondering) + if (Limits.ponder) return; bool stillAtFirstMove = FirstRootMove @@ -2061,9 +1851,9 @@ split_point_start: // At split points actual search starts from here bool noMoreTime = t > TimeMgr.maximum_time() || stillAtFirstMove; - if ( (UseTimeManagement && noMoreTime) - || (ExactMaxTime && t >= ExactMaxTime) - || (MaxNodes && pos.nodes_searched() >= MaxNodes)) // FIXME + if ( (Limits.useTimeManagement() && noMoreTime) + || (Limits.maxTime && t >= Limits.maxTime) + || (Limits.maxNodes && pos.nodes_searched() >= Limits.maxNodes)) // FIXME StopRequest = true; } @@ -2079,447 +1869,56 @@ split_point_start: // At split points actual search starts from here std::string command; - while (true) - { - // Wait for a command from stdin - if (!std::getline(std::cin, command)) - command = "quit"; - - if (command == "quit") - { - QuitRequest = true; - break; - } - else if (command == "ponderhit" || command == "stop") - break; - } - } - - - // 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) { + // Wait for a command from stdin + while ( std::getline(std::cin, command) + && command != "ponderhit" && command != "stop" && command != "quit") {}; - ThreadsMgr.idle_loop(*(int*)threadID, NULL); - return 0; + if (command != "ponderhit" && command != "stop") + QuitRequest = true; // Must be "quit" or getline() returned false } -#endif + // 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) { - /// The ThreadsManager class + assert(MultiPV > 1); + static RKISS rk; - // 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. + // 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; - void ThreadsManager::read_uci_options() { + // PRNG sequence should be non deterministic + for (int i = abs(get_system_time() % 50); i > 0; i--) + rk.rand(); - 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(); - } - - - // 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 = false; - - while (true) + // 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++) { - // 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 wake_sleeping_thread() - lock_grab(&sleepLock[threadID]); - - // 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(&sleepLock[threadID]); - break; - } - - // Do sleep here after retesting sleep conditions - if (threadID >= activeThreads || threads[threadID].state == THREAD_AVAILABLE) - cond_wait(&sleepCond[threadID], &sleepLock[threadID]); - - lock_release(&sleepLock[threadID]); - } - - // If this thread has been assigned work, launch a search - if (threads[threadID].state == THREAD_WORKISWAITING) - { - assert(!allThreadsShouldExit); - - threads[threadID].state = THREAD_SEARCHING; - - // Here we call search() with SplitPoint template parameter set to true - SplitPoint* tsp = threads[threadID].splitPoint; - Position pos(*tsp->pos, threadID); - SearchStack* ss = tsp->sstack[threadID] + 1; - ss->sp = tsp; - - if (tsp->pvNode) - search(pos, ss, tsp->alpha, tsp->beta, tsp->depth, tsp->ply); - else - search(pos, ss, tsp->alpha, tsp->beta, tsp->depth, tsp->ply); - - assert(threads[threadID].state == THREAD_SEARCHING); + s = Rml[i].pv_score; - 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) - wake_sleeping_thread(tsp->master); - } - - // 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)); - - // 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); - - threads[threadID].state = THREAD_SEARCHING; - return; - } - } - } - - - // init_threads() is called during startup. It launches all helper threads, - // and initializes the split point stack and the global locks and condition - // objects. - - void ThreadsManager::init_threads() { - - int i, arg[MAX_THREADS]; - bool ok; - - // Initialize global locks - lock_init(&mpLock); - - for (i = 0; i < MAX_THREADS; i++) - { - lock_init(&sleepLock[i]); - cond_init(&sleepCond[i]); - } - - // Initialize splitPoints[] locks - for (i = 0; i < MAX_THREADS; i++) - for (int j = 0; j < MAX_ACTIVE_SPLIT_POINTS; j++) - lock_init(&(threads[i].splitPoints[j].lock)); - - // Will be set just before program exits to properly end the threads - allThreadsShouldExit = false; - - // Threads will be put all threads to sleep as soon as created - activeThreads = 1; + // Don't allow crazy blunders even at very low skills + if (i > 0 && Rml[i-1].pv_score > s + EasyMoveMargin) + break; - // All threads except the main thread should be initialized to THREAD_INITIALIZING - threads[0].state = THREAD_SEARCHING; - for (i = 1; i < MAX_THREADS; i++) - threads[i].state = THREAD_INITIALIZING; + // This is our magical formula + s += ((max - s) * wk + var * (rk.rand() % wk)) / 128; - // Launch the helper threads - for (i = 1; i < MAX_THREADS; i++) - { - 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) + if (s > max_s) { - cout << "Failed to create thread number " << i << endl; - exit(EXIT_FAILURE); + max_s = s; + *best = Rml[i].pv[0]; + *ponder = Rml[i].pv[1]; } - - // 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() { - - allThreadsShouldExit = true; // Let the woken up threads to exit idle_loop() - - // Wake up all the threads and waits for termination - for (int i = 1; i < MAX_THREADS; i++) - { - wake_sleeping_thread(i); - while (threads[i].state != THREAD_TERMINATED) {} - } - - // Now we can safely destroy the locks - for (int i = 0; i < MAX_THREADS; i++) - for (int j = 0; j < MAX_ACTIVE_SPLIT_POINTS; j++) - lock_destroy(&(threads[i].splitPoints[j].lock)); - - lock_destroy(&mpLock); - - // Now we can safely destroy the wait conditions - for (int i = 0; i < MAX_THREADS; i++) - { - lock_destroy(&sleepLock[i]); - cond_destroy(&sleepCond[i]); - } - } - - - // 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; - } - - - // 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; - } - - - // available_thread_exists() tries to find an idle thread which is available as - // a slave for the thread with threadID "master". - - bool ThreadsManager::available_thread_exists(int master) const { - - 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; - } - - - // 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, int ply, Value* alpha, - const Value beta, Value* bestValue, Depth depth, Move threatMove, - bool mateThreat, int moveCount, MovePicker* mp, bool pvNode) { - assert(pos.is_ok()); - assert(ply > 0 && ply < PLY_MAX); - 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) - { - 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.ply = ply; - splitPoint.depth = depth; - splitPoint.threatMove = threatMove; - splitPoint.mateThreat = mateThreat; - 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.parentSstack = 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++; - } - - assert(Fake || workersCnt > 1); - - // We can release the lock because slave threads are already booked and master is not available - lock_release(&mpLock); - - // Tell the threads that they have work to do. This will make them leave - // their idle loop. But before copy search stack tail for each thread. - for (i = 0; i < activeThreads; i++) - if (i == master || splitPoint.slaves[i]) - { - memcpy(splitPoint.sstack[i], ss - 1, 4 * sizeof(SearchStack)); - - 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) - wake_sleeping_thread(i); - } - - // 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); - } - - - // wake_sleeping_thread() wakes up the thread with the given threadID - // when it is time to start a new search. - - void ThreadsManager::wake_sleeping_thread(int threadID) { - - lock_grab(&sleepLock[threadID]); - cond_signal(&sleepCond[threadID]); - lock_release(&sleepLock[threadID]); } @@ -2546,6 +1945,33 @@ split_point_start: // At split points actual search starts from here return *this; } + void RootMoveList::init(Position& pos, Move searchMoves[]) { + + MoveStack mlist[MAX_MOVES]; + Move* sm; + + clear(); + bestMoveChanges = 0; + + // 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++) {} + + if (searchMoves[0] && *sm != cur->move) + continue; + + RootMove rm; + rm.pv[0] = cur->move; + rm.pv[1] = MOVE_NONE; + rm.pv_score = -VALUE_INFINITE; + push_back(rm); + } + } + // extract_pv_from_tt() builds a PV by adding moves from the transposition table. // We consider also failing high nodes and not only VALUE_TYPE_EXACT nodes. This // allow to always have a ponder move even when we fail high at root and also a @@ -2557,13 +1983,13 @@ split_point_start: // At split points actual search starts from here TTEntry* tte; int ply = 1; - assert(pv[0] != MOVE_NONE && move_is_legal(pos, pv[0])); + assert(pv[0] != MOVE_NONE && pos.move_is_legal(pv[0])); pos.do_move(pv[0], *st++); while ( (tte = TT.retrieve(pos.get_key())) != NULL && tte->move() != MOVE_NONE - && move_is_legal(pos, tte->move()) + && pos.move_is_legal(tte->move()) && ply < PLY_MAX && (!pos.is_draw() || ply < 2)) { @@ -2587,13 +2013,13 @@ split_point_start: // At split points actual search starts from here Value v, m = VALUE_NONE; int ply = 0; - assert(pv[0] != MOVE_NONE && move_is_legal(pos, pv[0])); + assert(pv[0] != MOVE_NONE && pos.move_is_legal(pv[0])); do { k = pos.get_key(); tte = TT.retrieve(k); - // Don't overwrite exsisting correct entries + // Don't overwrite existing correct entries if (!tte || tte->move() != pv[ply]) { v = (pos.is_check() ? VALUE_NONE : evaluate(pos, m)); @@ -2607,94 +2033,167 @@ split_point_start: // At split points actual search starts from here } // pv_info_to_uci() returns a string with information on the current PV line - // formatted according to UCI specification and eventually writes the info - // to a log file. It is called at each iteration or after a new pv is found. - - std::string RootMove::pv_info_to_uci(const Position& pos, Value alpha, Value beta, int pvLine) { - - std::stringstream s, l; - Move* m = pv; + // formatted according to UCI specification. - while (*m != MOVE_NONE) - l << *m++ << " "; + 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 " << Iteration // FIXME - << " seldepth " << int(m - pv) - << " multipv " << pvLine + 1 + s << "info depth " << depth + << " seldepth " << selDepth + << " multipv " << pvIdx + 1 << " score " << value_to_uci(pv_score) << (pv_score >= beta ? " lowerbound" : pv_score <= alpha ? " upperbound" : "") - << " time " << current_search_time() - << " nodes " << pos.nodes_searched() - << " nps " << nps(pos) - << " pv " << l.str(); + << speed_to_uci(pos.nodes_searched()) + << " pv "; - if (UseLogFile && pvLine == 0) - { - ValueType t = pv_score >= beta ? VALUE_TYPE_LOWER : - pv_score <= alpha ? VALUE_TYPE_UPPER : VALUE_TYPE_EXACT; + for (Move* m = pv; *m != MOVE_NONE; m++) + s << *m << " "; - LogFile << pretty_pv(pos, current_search_time(), Iteration, pv_score, t, pv) << endl; - } return s.str(); } + // Specializations for MovePickerExt in case of Root node + MovePickerExt::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; + } - RootMoveList::RootMoveList(Position& pos, Move searchMoves[]) { + Rml.sort(); + rm = Rml.begin(); + } - SearchStack ss[PLY_MAX_PLUS_2]; - MoveStack mlist[MOVES_MAX]; - StateInfo st; - Move* sm; + Move MovePickerExt::get_next_move() { - // Initialize search stack - init_ss_array(ss, PLY_MAX_PLUS_2); - ss[0].eval = ss[0].evalMargin = VALUE_NONE; + if (!firstCall) + ++rm; + else + firstCall = false; - // Generate all legal moves - MoveStack* last = generate_moves(pos, mlist); + return rm != Rml.end() ? rm->pv[0] : MOVE_NONE; + } - // Add each move to the RootMoveList's vector - 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++) {} +} // namespace - if (searchMoves[0] && *sm != cur->move) - continue; - // Find a quick score for the move and add to the list - pos.do_move(cur->move, st); +// ThreadsManager::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. - RootMove rm; - rm.pv[0] = ss[0].currentMove = cur->move; - rm.pv[1] = MOVE_NONE; - rm.pv_score = -qsearch(pos, ss+1, -VALUE_INFINITE, VALUE_INFINITE, DEPTH_ZERO, 1); - push_back(rm); +void ThreadsManager::idle_loop(int threadID, SplitPoint* sp) { - pos.undo_move(cur->move); - } - sort(); - } + assert(threadID >= 0 && threadID < MAX_THREADS); - // Score root moves using the standard way used in main search, the moves - // are scored according to the order in which are returned by MovePicker. - // This is the second order score that is used to compare the moves when - // the first order pv scores of both moves are equal. + int i; + bool allFinished; - void RootMoveList::set_non_pv_scores(const Position& pos) + while (true) { - Move move; - Value score = VALUE_ZERO; - MovePicker mp(pos, MOVE_NONE, ONE_PLY, H); + // 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; + } - while ((move = mp.get_next_move()) != MOVE_NONE) - for (Base::iterator it = begin(); it != end(); ++it) - if (it->pv[0] == move) - { - it->non_pv_score = score--; - break; - } - } + // 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); -} // namespace + 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->is_slave[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->is_slave[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)); + + // 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); + + threads[threadID].state = Thread::SEARCHING; + return; + } + } +}