X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=f259ab707fe7983a271bdd6b05093490d6fe404a;hp=dd9e45b92e33b3ad606b6c10a40294fa77349058;hb=6247f27a0548562c122f658082d31f535208d603;hpb=aa86d81f79a92a5a050f73e1443190e53aa9f2ed diff --git a/src/search.cpp b/src/search.cpp index dd9e45b9..f259ab70 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -23,6 +23,7 @@ //// #include +#include #include #include #include @@ -31,6 +32,7 @@ #include "book.h" #include "evaluate.h" #include "history.h" +#include "maxgain.h" #include "misc.h" #include "movegen.h" #include "movepick.h" @@ -41,6 +43,8 @@ #include "tt.h" #include "ucioption.h" +using std::cout; +using std::endl; //// //// Local definitions @@ -86,20 +90,27 @@ namespace { }; - // The RootMove class is used for moves at the root at the tree. For each + // The RootMove class is used for moves at the root at the tree. For each // root move, we store a score, a node count, and a PV (really a refutation // in the case of moves which fail low). struct RootMove { - RootMove(); - bool operator<(const RootMove&); // used to sort + RootMove() { nodes = cumulativeNodes = ourBeta = theirBeta = 0ULL; } + + // 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 a higher score, or if the moves + // have equal score but m1 has the higher node count. + bool operator<(const RootMove& m) const { + + return score != m.score ? score < m.score : theirBeta <= m.theirBeta; + } Move move; Value score; - int64_t nodes, cumulativeNodes; + int64_t nodes, cumulativeNodes, ourBeta, theirBeta; Move pv[PLY_MAX_PLUS_2]; - int64_t ourBeta, theirBeta; }; @@ -110,16 +121,18 @@ namespace { public: RootMoveList(Position& pos, Move searchMoves[]); - inline Move get_move(int moveNum) const; - inline Value get_move_score(int moveNum) const; - inline void set_move_score(int moveNum, Value score); - inline void set_move_nodes(int moveNum, int64_t nodes); - inline void set_beta_counters(int moveNum, int64_t our, int64_t their); + + int move_count() const { return count; } + Move get_move(int moveNum) const { return moves[moveNum].move; } + Value get_move_score(int moveNum) const { return moves[moveNum].score; } + void set_move_score(int moveNum, Value score) { moves[moveNum].score = score; } + Move get_move_pv(int moveNum, int i) const { return moves[moveNum].pv[i]; } + int64_t get_move_cumulative_nodes(int moveNum) const { return moves[moveNum].cumulativeNodes; } + + void set_move_nodes(int moveNum, int64_t nodes); + void set_beta_counters(int moveNum, int64_t our, int64_t their); void set_move_pv(int moveNum, const Move pv[]); - inline Move get_move_pv(int moveNum, int i) const; - inline int64_t get_move_cumulative_nodes(int moveNum) const; - inline int move_count() const; - inline void sort(); + void sort(); void sort_multipv(int n); private: @@ -132,7 +145,7 @@ namespace { /// Constants // Search depth at iteration 1 - const Depth InitialDepth = OnePly /*+ OnePly/2*/; + const Depth InitialDepth = OnePly; // Depth limit for selective search const Depth SelectiveDepth = 7 * OnePly; @@ -161,15 +174,9 @@ namespace { // best move from the previous iteration, Problem is set back to false. const Value NoProblemMargin = Value(0x14); - // Null move margin. A null move search will not be done if the approximate + // Null move margin. A null move search will not be done if the static // evaluation of the position is more than NullMoveMargin below beta. - const Value NullMoveMargin = Value(0x300); - - // Pruning criterions. See the code and comments in ok_to_prune() to - // understand their precise meaning. - const bool PruneEscapeMoves = false; - const bool PruneDefendingMoves = false; - const bool PruneBlockingMoves = false; + const Value NullMoveMargin = Value(0x200); // If the TT move is at least SingleReplyMargin better then the // remaining ones we will extend it. @@ -182,23 +189,13 @@ namespace { // Each move futility margin is decreased const Value IncrementalFutilityMargin = Value(0x8); - // Razoring - const Depth RazorDepth = 4*OnePly; - - // Remaining depth: 1 ply 1.5 ply 2 ply 2.5 ply 3 ply 3.5 ply - const Value RazorMargins[6] = { Value(0x180), Value(0x300), Value(0x300), Value(0x3C0), Value(0x3C0), Value(0x3C0) }; - - // Remaining depth: 1 ply 1.5 ply 2 ply 2.5 ply 3 ply 3.5 ply - const Value RazorApprMargins[6] = { Value(0x520), Value(0x300), Value(0x300), Value(0x300), Value(0x300), Value(0x300) }; - + // Depth limit for razoring + const Depth RazorDepth = 4 * OnePly; /// Variables initialized by UCI options - // Minimum number of full depth (i.e. non-reduced) moves at PV and non-PV nodes - int LMRPVMoves, LMRNonPVMoves; // heavy SMP read access for the latter - // Depth limit for use of dynamic threat detection - Depth ThreatDepth; // heavy SMP read access + Depth ThreatDepth; // Last seconds noise filtering (LSN) const bool UseLSNFiltering = true; @@ -207,13 +204,12 @@ namespace { bool loseOnTime = false; // Extensions. Array index 0 is used at non-PV nodes, index 1 at PV nodes. - // There is heavy SMP read access on these arrays - Depth CheckExtension[2], SingleReplyExtension[2], PawnPushTo7thExtension[2]; + Depth CheckExtension[2], SingleEvasionExtension[2], PawnPushTo7thExtension[2]; Depth PassedPawnExtension[2], PawnEndgameExtension[2], MateThreatExtension[2]; // Iteration counters int Iteration; - BetaCounterType BetaCounter; // has per-thread internal data + BetaCounterType BetaCounter; // Scores and number of times the best move changed for each iteration IterationInfoType IterationInfo[PLY_MAX_PLUS_2]; @@ -223,18 +219,13 @@ namespace { int MultiPV; // Time managment variables + int RootMoveNumber; int SearchStartTime; int MaxNodes, MaxDepth; int MaxSearchTime, AbsoluteMaxSearchTime, ExtraSearchTime, ExactMaxTime; - int RootMoveNumber; - bool InfiniteSearch; - bool PonderSearch; - bool StopOnPonderhit; - bool AbortSearch; // heavy SMP read access - bool Quit; - bool FailHigh; - bool FailLow; - bool Problem; + bool UseTimeManagement, InfiniteSearch, PonderSearch, StopOnPonderhit; + bool AbortSearch, Quit; + bool FailHigh, FailLow, Problem; // Show current line? bool ShowCurrentLine; @@ -243,6 +234,10 @@ namespace { bool UseLogFile; std::ofstream LogFile; + // Natural logarithmic lookup table and its getter function + double lnArray[512]; + inline double ln(int i) { return lnArray[i]; } + // MP related variables int ActiveThreads = 1; Depth MinimumSplitDepth; @@ -251,8 +246,7 @@ namespace { Lock MPLock; Lock IOLock; bool AllThreadsShouldExit = false; - const int MaxActiveSplitPoints = 8; - SplitPoint SplitPointStack[THREAD_MAX][MaxActiveSplitPoints]; + SplitPoint SplitPointStack[THREAD_MAX][ACTIVE_SPLIT_POINTS_MAX]; bool Idle = true; #if !defined(_MSC_VER) @@ -270,6 +264,8 @@ namespace { // History table History H; + // MaxGain table + MaxGain MG; /// Functions @@ -286,11 +282,12 @@ namespace { bool connected_moves(const Position& pos, Move m1, Move m2); bool value_is_mate(Value value); bool move_is_killer(Move m, const SearchStack& ss); - Depth extension(const Position& pos, Move m, bool pvNode, bool capture, bool check, bool singleReply, bool mateThreat, bool* dangerous); + Depth extension(const Position&, Move, bool, bool, bool, bool, bool, bool*); bool ok_to_do_nullmove(const Position& pos); bool ok_to_prune(const Position& pos, Move m, Move threat); bool ok_to_use_TT(const TTEntry* tte, Depth depth, Value beta, int ply); - void update_history(const Position& pos, Move m, Depth depth, Move movesSearched[], int moveCount); + 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); bool fail_high_ply_1(); @@ -310,8 +307,7 @@ namespace { bool idle_thread_exists(int master); bool split(const Position& pos, SearchStack* ss, int ply, Value *alpha, Value *beta, Value *bestValue, - const Value futilityValue, const Value approximateValue, - Depth depth, int *moves, + const Value futilityValue, Depth depth, int *moves, MovePicker *mp, int master, bool pvNode); void wake_sleeping_threads(); @@ -329,8 +325,8 @@ namespace { //// -/// 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 is bug free. All the legal +/// moves up to given depth are generated and counted and the sum returned. int perft(Position& pos, Depth depth) { @@ -368,8 +364,20 @@ bool think(const Position& pos, bool infinite, bool ponder, int side_to_move, int time[], int increment[], int movesToGo, int maxDepth, int maxNodes, int maxTime, Move searchMoves[]) { - // Look for a book move - if (!infinite && !ponder && get_option_value_bool("OwnBook")) + // Initialize global search variables + Idle = StopOnPonderhit = AbortSearch = Quit = false; + FailHigh = FailLow = Problem = false; + NodesSincePoll = 0; + SearchStartTime = get_system_time(); + ExactMaxTime = maxTime; + MaxDepth = maxDepth; + MaxNodes = maxNodes; + InfiniteSearch = infinite; + PonderSearch = ponder; + UseTimeManagement = !ExactMaxTime && !MaxDepth && !MaxNodes && !InfiniteSearch; + + // Look for a book move, only during games, not tests + if (UseTimeManagement && !ponder && get_option_value_bool("OwnBook")) { Move bookMove; if (get_option_value_string("Book File") != OpeningBook.file_name()) @@ -378,32 +386,19 @@ bool think(const Position& pos, bool infinite, bool ponder, int side_to_move, bookMove = OpeningBook.get_move(pos); if (bookMove != MOVE_NONE) { - std::cout << "bestmove " << bookMove << std::endl; + cout << "bestmove " << bookMove << endl; return true; } } - // Initialize global search variables - Idle = false; - SearchStartTime = get_system_time(); for (int i = 0; i < THREAD_MAX; i++) { Threads[i].nodes = 0ULL; Threads[i].failHighPly1 = false; } - NodesSincePoll = 0; - InfiniteSearch = infinite; - PonderSearch = ponder; - StopOnPonderhit = false; - AbortSearch = false; - Quit = false; - FailHigh = false; - FailLow = false; - Problem = false; - ExactMaxTime = maxTime; if (button_was_pressed("New Game")) - loseOnTime = false; // reset at the beginning of a new game + loseOnTime = false; // Reset at the beginning of a new game // Read UCI option values TT.set_size(get_option_value_int("Hash")); @@ -416,8 +411,8 @@ bool think(const Position& pos, bool infinite, bool ponder, int side_to_move, CheckExtension[1] = Depth(get_option_value_int("Check Extension (PV nodes)")); CheckExtension[0] = Depth(get_option_value_int("Check Extension (non-PV nodes)")); - SingleReplyExtension[1] = Depth(get_option_value_int("Single Reply Extension (PV nodes)")); - SingleReplyExtension[0] = Depth(get_option_value_int("Single Reply Extension (non-PV nodes)")); + SingleEvasionExtension[1] = Depth(get_option_value_int("Single Evasion Extension (PV nodes)")); + SingleEvasionExtension[0] = Depth(get_option_value_int("Single Evasion Extension (non-PV nodes)")); PawnPushTo7thExtension[1] = Depth(get_option_value_int("Pawn Push to 7th Extension (PV nodes)")); PawnPushTo7thExtension[0] = Depth(get_option_value_int("Pawn Push to 7th Extension (non-PV nodes)")); @@ -431,8 +426,6 @@ bool think(const Position& pos, bool infinite, bool ponder, int side_to_move, MateThreatExtension[1] = Depth(get_option_value_int("Mate Threat Extension (PV nodes)")); MateThreatExtension[0] = Depth(get_option_value_int("Mate Threat Extension (non-PV nodes)")); - LMRPVMoves = get_option_value_int("Full Depth Moves (PV nodes)") + 1; - LMRNonPVMoves = get_option_value_int("Full Depth Moves (non-PV nodes)") + 1; ThreatDepth = get_option_value_int("Threat Depth") * OnePly; Chess960 = get_option_value_bool("UCI_Chess960"); @@ -452,6 +445,10 @@ bool think(const Position& pos, bool infinite, bool ponder, int side_to_move, { ActiveThreads = newActiveThreads; init_eval(ActiveThreads); + // HACK: init_eval() destroys the static castleRightsMask[] array in the + // Position class. The below line repairs the damage. + Position p(pos.to_fen()); + assert(pos.is_ok()); } // Wake up sleeping threads @@ -463,48 +460,45 @@ bool think(const Position& pos, bool infinite, bool ponder, int side_to_move, // Set thinking time int myTime = time[side_to_move]; int myIncrement = increment[side_to_move]; - - if (!movesToGo) // Sudden death time control + if (UseTimeManagement) { - if (myIncrement) + if (!movesToGo) // Sudden death time control { - MaxSearchTime = myTime / 30 + myIncrement; - AbsoluteMaxSearchTime = Max(myTime / 4, myIncrement - 100); - } else { // Blitz game without increment - MaxSearchTime = myTime / 30; - AbsoluteMaxSearchTime = myTime / 8; + if (myIncrement) + { + MaxSearchTime = myTime / 30 + myIncrement; + AbsoluteMaxSearchTime = Max(myTime / 4, myIncrement - 100); + } + else // Blitz game without increment + { + MaxSearchTime = myTime / 30; + AbsoluteMaxSearchTime = myTime / 8; + } } - } - else // (x moves) / (y minutes) - { - if (movesToGo == 1) + else // (x moves) / (y minutes) { - MaxSearchTime = myTime / 2; - AbsoluteMaxSearchTime = - (myTime > 3000)? (myTime - 500) : ((myTime * 3) / 4); - } else { - MaxSearchTime = myTime / Min(movesToGo, 20); - AbsoluteMaxSearchTime = Min((4 * myTime) / movesToGo, myTime / 3); + if (movesToGo == 1) + { + MaxSearchTime = myTime / 2; + AbsoluteMaxSearchTime = (myTime > 3000)? (myTime - 500) : ((myTime * 3) / 4); + } + else + { + MaxSearchTime = myTime / Min(movesToGo, 20); + AbsoluteMaxSearchTime = Min((4 * myTime) / movesToGo, myTime / 3); + } } - } - if (PonderingEnabled) - { - MaxSearchTime += MaxSearchTime / 4; - MaxSearchTime = Min(MaxSearchTime, AbsoluteMaxSearchTime); + if (PonderingEnabled) + { + MaxSearchTime += MaxSearchTime / 4; + MaxSearchTime = Min(MaxSearchTime, AbsoluteMaxSearchTime); + } } - // Fixed depth or fixed number of nodes? - MaxDepth = maxDepth; - if (MaxDepth) - InfiniteSearch = true; // HACK - - MaxNodes = maxNodes; + // Set best NodesBetweenPolls interval if (MaxNodes) - { NodesBetweenPolls = Min(MaxNodes, 30000); - InfiniteSearch = true; // HACK - } else if (myTime && myTime < 1000) NodesBetweenPolls = 1000; else if (myTime && myTime < 5000) @@ -514,13 +508,12 @@ bool think(const Position& pos, bool infinite, bool ponder, int side_to_move, // Write information to search log file if (UseLogFile) - LogFile << "Searching: " << pos.to_fen() << std::endl + LogFile << "Searching: " << pos.to_fen() << endl << "infinite: " << infinite << " ponder: " << ponder << " time: " << myTime << " increment: " << myIncrement - << " moves to go: " << movesToGo << std::endl; - + << " moves to go: " << movesToGo << endl; // LSN filtering. Used only for developing purpose. Disabled by default. if ( UseLSNFiltering @@ -528,13 +521,13 @@ bool think(const Position& pos, bool infinite, bool ponder, int side_to_move, { // Step 2. If after last move we decided to lose on time, do it now! while (SearchStartTime + myTime + 1000 > get_system_time()) - ; // wait here + /* wait here */; } // We're ready to start thinking. Call the iterative deepening loop function Value v = id_loop(pos, searchMoves); - // LSN filtering. Used only for developing purpose. Disabled by default. + if (UseLSNFiltering) { // Step 1. If this is sudden death game and our position is hopeless, @@ -562,18 +555,23 @@ bool think(const Position& pos, bool infinite, bool ponder, int side_to_move, } -/// init_threads() is called during startup. It launches all helper threads, +/// 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 init_threads() { volatile int i; + bool ok; #if !defined(_MSC_VER) pthread_t pthread[1]; #endif + // Init our logarithmic lookup table + for (i = 0; i < 512; i++) + lnArray[i] = log(double(i)); // log() returns base-e logarithm + for (i = 0; i < THREAD_MAX; i++) Threads[i].activeSplitPoints = 0; @@ -601,22 +599,28 @@ void init_threads() { } // Launch the helper threads - for(i = 1; i < THREAD_MAX; i++) + for (i = 1; i < THREAD_MAX; i++) { #if !defined(_MSC_VER) - pthread_create(pthread, NULL, init_thread, (void*)(&i)); + ok = (pthread_create(pthread, NULL, init_thread, (void*)(&i)) == 0); #else DWORD iID[1]; - CreateThread(NULL, 0, init_thread, (LPVOID)(&i), 0, iID); + ok = (CreateThread(NULL, 0, init_thread, (LPVOID)(&i), 0, iID) != NULL); #endif + if (!ok) + { + cout << "Failed to create thread number " << i << endl; + Application::exit_with_failure(); + } + // Wait until the thread has finished launching while (!Threads[i].running); } } -/// stop_threads() is called when the program exits. It makes all the +/// stop_threads() is called when the program exits. It makes all the /// helper threads exit cleanly. void stop_threads() { @@ -628,7 +632,7 @@ void stop_threads() { for (int i = 1; i < THREAD_MAX; i++) { Threads[i].stop = true; - while(Threads[i].running); + while (Threads[i].running); } destroy_split_point_stack(); } @@ -653,6 +657,8 @@ void SearchStack::init(int ply) { pv[ply] = pv[ply + 1] = MOVE_NONE; currentMove = threatMove = MOVE_NONE; reduction = Depth(0); + eval = VALUE_NONE; + evalInfo = NULL; } void SearchStack::initKillers() { @@ -664,7 +670,7 @@ void SearchStack::initKillers() { namespace { - // id_loop() is the main iterative deepening loop. It calls root_search + // 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. @@ -687,16 +693,17 @@ namespace { // Print RootMoveList c'tor startup scoring to the standard output, // so that we print information also for iteration 1. - std::cout << "info depth " << 1 << "\ninfo depth " << 1 - << " score " << value_to_string(rml.get_move_score(0)) - << " time " << current_search_time() - << " nodes " << nodes_searched() - << " nps " << nps() - << " pv " << rml.get_move(0) << "\n"; + cout << "info depth " << 1 << "\ninfo depth " << 1 + << " score " << value_to_string(rml.get_move_score(0)) + << " time " << current_search_time() + << " nodes " << nodes_searched() + << " nps " << nps() + << " pv " << rml.get_move(0) << "\n"; // Initialize TT.new_search(); H.clear(); + MG.clear(); init_ss_array(ss); IterationInfo[1] = IterationInfoType(rml.get_move_score(0), rml.get_move_score(0)); Iteration = 1; @@ -717,7 +724,7 @@ namespace { if (Iteration <= 5) ExtraSearchTime = 0; - std::cout << "info depth " << Iteration << std::endl; + cout << "info depth " << Iteration << endl; // Calculate dynamic search window based on previous iterations Value alpha, beta; @@ -776,18 +783,19 @@ namespace { speculatedValue = Min(Max(speculatedValue, -VALUE_INFINITE), VALUE_INFINITE); IterationInfo[Iteration] = IterationInfoType(value, speculatedValue); - // Erase the easy move if it differs from the new best move + // Drop the easy move if it differs from the new best move if (ss[0].pv[0] != EasyMove) EasyMove = MOVE_NONE; Problem = false; - if (!InfiniteSearch) + if (UseTimeManagement) { // Time to stop? bool stopSearch = false; - // Stop search early if there is only a single legal move + // 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.move_count() == 1) stopSearch = true; @@ -815,9 +823,9 @@ namespace { + BestMoveChangesByIteration[Iteration-1] * (MaxSearchTime / 3); // 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 + // iteration. We probably don't have enough time to search the first // move at the next iteration anyway. - if (current_search_time() > ((MaxSearchTime + ExtraSearchTime)*80) / 128) + if (current_search_time() > ((MaxSearchTime + ExtraSearchTime) * 80) / 128) stopSearch = true; if (stopSearch) @@ -835,16 +843,16 @@ namespace { rml.sort(); - // If we are pondering, we shouldn't print the best move before we - // are told to do so - if (PonderSearch) + // If we are pondering or in infinite search, we shouldn't print the + // best move before we are told to do so. + if (!AbortSearch && (PonderSearch || InfiniteSearch)) wait_for_stop_or_ponderhit(); else // Print final search statistics - std::cout << "info nodes " << nodes_searched() - << " nps " << nps() - << " time " << current_search_time() - << " hashfull " << TT.full() << std::endl; + cout << "info nodes " << nodes_searched() + << " nps " << nps() + << " time " << current_search_time() + << " hashfull " << TT.full() << endl; // Print the best move and the ponder move to the standard output if (ss[0].pv[0] == MOVE_NONE) @@ -852,11 +860,11 @@ namespace { ss[0].pv[0] = rml.get_move(0); ss[0].pv[1] = MOVE_NONE; } - std::cout << "bestmove " << ss[0].pv[0]; + cout << "bestmove " << ss[0].pv[0]; if (ss[0].pv[1] != MOVE_NONE) - std::cout << " ponder " << ss[0].pv[1]; + cout << " ponder " << ss[0].pv[1]; - std::cout << std::endl; + cout << endl; if (UseLogFile) { @@ -866,29 +874,35 @@ namespace { if (dbg_show_hit_rate) dbg_print_hit_rate(LogFile); - StateInfo st; - LogFile << "Nodes: " << nodes_searched() << std::endl - << "Nodes/second: " << nps() << std::endl - << "Best move: " << move_to_san(p, ss[0].pv[0]) << std::endl; + LogFile << "\nNodes: " << nodes_searched() + << "\nNodes/second: " << nps() + << "\nBest move: " << move_to_san(p, ss[0].pv[0]); + StateInfo st; p.do_move(ss[0].pv[0], st); - LogFile << "Ponder move: " << move_to_san(p, ss[0].pv[1]) - << std::endl << std::endl; + LogFile << "\nPonder move: " << move_to_san(p, ss[0].pv[1]) << endl; } return rml.get_move_score(0); } - // root_search() is the function which searches the root node. It is + // root_search() is the function which searches the root node. It is // similar to search_pv except that it uses a different move ordering - // scheme (perhaps we should try to use this at internal PV nodes, too?) - // and prints some information to the standard output. + // scheme and prints some information to the standard output. - Value root_search(Position& pos, SearchStack ss[], RootMoveList &rml, Value alpha, Value beta) { + Value root_search(Position& pos, SearchStack ss[], RootMoveList& rml, Value alpha, Value beta) { Value oldAlpha = alpha; - Value value; + Value value = -VALUE_INFINITE; CheckInfo ci(pos); + bool isCheck = pos.is_check(); + + // Evaluate the position statically + EvalInfo ei; + if (!isCheck) + ss[0].eval = evaluate(pos, ei, 0); + else + ss[0].eval = VALUE_NONE; // Loop through all the moves in the root move list for (int i = 0; i < rml.move_count() && !AbortSearch; i++) @@ -904,13 +918,12 @@ namespace { int64_t nodes; Move move; StateInfo st; - Depth ext, newDepth; + Depth depth, ext, newDepth; RootMoveNumber = i + 1; FailHigh = false; - // Remember the node count before the move is searched. The node counts - // are used to sort the root moves at the next iteration. + // Save the current node count before the move is searched nodes = nodes_searched(); // Reset beta cut-off counters @@ -919,16 +932,18 @@ namespace { // Pick the next root move, and print the move and the move number to // the standard output. move = ss[0].currentMove = rml.get_move(i); + if (current_search_time() >= 1000) - std::cout << "info currmove " << move - << " currmovenumber " << i + 1 << std::endl; + cout << "info currmove " << move + << " currmovenumber " << RootMoveNumber << endl; // Decide search depth for this move bool moveIsCheck = pos.move_is_check(move); bool captureOrPromotion = pos.move_is_capture_or_promotion(move); bool dangerous; + depth = (Iteration - 2) * OnePly + InitialDepth; ext = extension(pos, move, true, captureOrPromotion, moveIsCheck, false, false, &dangerous); - newDepth = (Iteration - 2) * OnePly + ext + InitialDepth; + newDepth = depth + ext; // Make the move, and search it pos.do_move(move, st, ci, moveIsCheck); @@ -940,37 +955,47 @@ namespace { alpha = -VALUE_INFINITE; value = -search_pv(pos, ss, -beta, -alpha, newDepth, 1, 0); + // If the value has dropped a lot compared to the last iteration, // set the boolean variable Problem to true. This variable is used // for time managment: When Problem is true, we try to complete the // current iteration before playing a move. - Problem = (Iteration >= 2 && value <= IterationInfo[Iteration-1].value - ProblemMargin); + Problem = ( Iteration >= 2 + && value <= IterationInfo[Iteration - 1].value - ProblemMargin); if (Problem && StopOnPonderhit) StopOnPonderhit = false; } else { - if ( newDepth >= 3*OnePly - && i >= MultiPV + LMRPVMoves + // Try to reduce non-pv search depth by one ply if move seems not problematic, + // if the move fails high will be re-searched at full depth. + bool doFullDepthSearch = true; + + if ( depth >= 3*OnePly // FIXME was newDepth && !dangerous && !captureOrPromotion && !move_is_castle(move)) { - ss[0].reduction = OnePly; - value = -search(pos, ss, -alpha, newDepth-OnePly, 1, true, 0); - } else - value = alpha + 1; // Just to trigger next condition + double red = 0.5 + ln(RootMoveNumber - MultiPV + 1) * ln(depth / 2) / 6.0; + if (red >= 1.0) + { + ss[0].reduction = Depth(int(floor(red * int(OnePly)))); + value = -search(pos, ss, -alpha, newDepth-ss[0].reduction, 1, true, 0); + doFullDepthSearch = (value > alpha); + } + } - if (value > alpha) + if (doFullDepthSearch) { value = -search(pos, ss, -alpha, newDepth, 1, true, 0); + if (value > alpha) { // Fail high! Set the boolean variable FailHigh to true, and - // re-search the move with a big window. The variable FailHigh is - // used for time managment: We try to avoid aborting the search - // prematurely during a fail high research. + // re-search the move using a PV search. The variable FailHigh + // is used for time managment: We try to avoid aborting the + // search prematurely during a fail high research. FailHigh = true; value = -search_pv(pos, ss, -beta, -alpha, newDepth, 1, 0); } @@ -987,14 +1012,12 @@ namespace { if (AbortSearch) break; - // Remember the node count for this move. The node counts are used to - // sort the root moves at the next iteration. - rml.set_move_nodes(i, nodes_searched() - nodes); - - // Remember the beta-cutoff statistics + // Remember beta-cutoff and searched nodes counts for this move. The + // info is used to sort the root moves at the next iteration. int64_t our, their; BetaCounter.read(pos.side_to_move(), our, their); rml.set_beta_counters(i, our, their); + rml.set_move_nodes(i, nodes_searched() - nodes); assert(value >= -VALUE_INFINITE && value <= VALUE_INFINITE); @@ -1019,27 +1042,28 @@ namespace { BestMoveChangesByIteration[Iteration]++; // Print search information to the standard output - std::cout << "info depth " << Iteration - << " score " << value_to_string(value) - << ((value >= beta)? - " lowerbound" : ((value <= alpha)? " upperbound" : "")) - << " time " << current_search_time() - << " nodes " << nodes_searched() - << " nps " << nps() - << " pv "; + cout << "info depth " << Iteration + << " score " << value_to_string(value) + << ((value >= beta) ? " lowerbound" : + ((value <= alpha)? " upperbound" : "")) + << " time " << current_search_time() + << " nodes " << nodes_searched() + << " nps " << nps() + << " pv "; for (int j = 0; ss[0].pv[j] != MOVE_NONE && j < PLY_MAX; j++) - std::cout << ss[0].pv[j] << " "; + cout << ss[0].pv[j] << " "; - std::cout << std::endl; + cout << endl; if (UseLogFile) - LogFile << pretty_pv(pos, current_search_time(), Iteration, nodes_searched(), value, - ((value >= beta)? VALUE_TYPE_LOWER - : ((value <= alpha)? VALUE_TYPE_UPPER : VALUE_TYPE_EXACT)), - ss[0].pv) - << std::endl; + { + ValueType type = (value >= beta ? VALUE_TYPE_LOWER + : (value <= alpha ? VALUE_TYPE_UPPER : VALUE_TYPE_EXACT)); + LogFile << pretty_pv(pos, current_search_time(), Iteration, + nodes_searched(), value, type, ss[0].pv) << endl; + } if (value > alpha) alpha = value; @@ -1053,23 +1077,22 @@ namespace { rml.sort_multipv(i); for (int j = 0; j < Min(MultiPV, rml.move_count()); j++) { - int k; - std::cout << "info multipv " << j + 1 - << " score " << value_to_string(rml.get_move_score(j)) - << " depth " << ((j <= i)? Iteration : Iteration - 1) - << " time " << current_search_time() - << " nodes " << nodes_searched() - << " nps " << nps() - << " pv "; - - for (k = 0; rml.get_move_pv(j, k) != MOVE_NONE && k < PLY_MAX; k++) - std::cout << rml.get_move_pv(j, k) << " "; - - std::cout << std::endl; + cout << "info multipv " << j + 1 + << " score " << value_to_string(rml.get_move_score(j)) + << " depth " << ((j <= i)? Iteration : Iteration - 1) + << " time " << current_search_time() + << " nodes " << nodes_searched() + << " nps " << nps() + << " pv "; + + for (int k = 0; rml.get_move_pv(j, k) != MOVE_NONE && k < PLY_MAX; k++) + cout << rml.get_move_pv(j, k) << " "; + + cout << endl; } alpha = rml.get_move_score(Min(i, MultiPV-1)); } - } // New best move case + } // PV move or new best move assert(alpha >= oldAlpha); @@ -1090,15 +1113,14 @@ namespace { assert(threadID >= 0 && threadID < ActiveThreads); Move movesSearched[256]; - EvalInfo ei; StateInfo st; const TTEntry* tte; Move ttMove, move; Depth ext, newDepth; Value oldAlpha, value; - bool isCheck, mateThreat, singleReply, moveIsCheck, captureOrPromotion, dangerous; + bool isCheck, mateThreat, singleEvasion, moveIsCheck, captureOrPromotion, dangerous; int moveCount = 0; - Value bestValue = -VALUE_INFINITE; + Value bestValue = value = -VALUE_INFINITE; if (depth < OnePly) return qsearch(pos, ss, alpha, beta, Depth(0), ply, threadID); @@ -1111,12 +1133,9 @@ namespace { if (AbortSearch || thread_should_stop(threadID)) return Value(0); - if (pos.is_draw()) + if (pos.is_draw() || ply >= PLY_MAX - 1) return VALUE_DRAW; - if (ply >= PLY_MAX - 1) - return pos.is_check() ? quick_evaluate(pos) : evaluate(pos, ei, threadID); - // Mate distance pruning oldAlpha = alpha; alpha = Max(value_mated_in(ply), alpha); @@ -1137,16 +1156,34 @@ namespace { ttMove = (tte ? tte->move() : MOVE_NONE); // Go with internal iterative deepening if we don't have a TT move - if (UseIIDAtPVNodes && ttMove == MOVE_NONE && depth >= 5*OnePly) + if ( UseIIDAtPVNodes + && depth >= 5*OnePly + && ttMove == MOVE_NONE) { search_pv(pos, ss, alpha, beta, depth-2*OnePly, ply, threadID); ttMove = ss[ply].pv[ply]; tte = TT.retrieve(pos.get_key()); } + // Evaluate the position statically + isCheck = pos.is_check(); + EvalInfo ei; + if (!isCheck) + { + ss[ply].eval = evaluate(pos, ei, threadID); + + // Store gain statistics + Move m = ss[ply - 1].currentMove; + if ( m != MOVE_NULL + && pos.captured_piece() == NO_PIECE_TYPE + && !move_is_castle(m) + && !move_is_promotion(m)) + MG.store(pos.piece_on(move_to(m)), move_from(m), move_to(m), ss[ply - 1].eval, -ss[ply].eval); + + } + // Initialize a MovePicker object for the current position, and prepare // to search all moves - isCheck = pos.is_check(); mateThreat = pos.has_mate_threat(opposite_color(pos.side_to_move())); CheckInfo ci(pos); MovePicker mp = MovePicker(pos, ttMove, depth, H, &ss[ply]); @@ -1159,17 +1196,16 @@ namespace { { assert(move_is_ok(move)); - singleReply = (isCheck && mp.number_of_evasions() == 1); + singleEvasion = (isCheck && mp.number_of_evasions() == 1); moveIsCheck = pos.move_is_check(move, ci); captureOrPromotion = pos.move_is_capture_or_promotion(move); // Decide the new search depth - ext = extension(pos, move, true, captureOrPromotion, moveIsCheck, singleReply, mateThreat, &dangerous); + ext = extension(pos, move, true, captureOrPromotion, moveIsCheck, singleEvasion, mateThreat, &dangerous); - // We want to extend the TT move if it is much better then remaining ones. - // To verify this we do a reduced search on all the other moves but the ttMove, - // if result is lower then TT value minus a margin then we assume ttMove is the - // only one playable. It is a kind of relaxed single reply extension. + // Singular extension search. We extend the TT move if its value is much better than + // its siblings. 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. if ( depth >= 6 * OnePly && tte && move == tte->move() @@ -1183,8 +1219,6 @@ namespace { { Value excValue = search(pos, ss, ttValue - SingleReplyMargin, depth / 2, ply, false, threadID, move); - // If search result is well below the foreseen score of the ttMove then we - // assume ttMove is the only one realistically playable and we extend it. if (excValue < ttValue - SingleReplyMargin) ext = OnePly; } @@ -1204,20 +1238,24 @@ namespace { { // Try to reduce non-pv search depth by one ply if move seems not problematic, // if the move fails high will be re-searched at full depth. + bool doFullDepthSearch = true; + if ( depth >= 3*OnePly - && moveCount >= LMRPVMoves && !dangerous && !captureOrPromotion && !move_is_castle(move) && !move_is_killer(move, ss[ply])) { - ss[ply].reduction = OnePly; - value = -search(pos, ss, -alpha, newDepth-OnePly, ply+1, true, threadID); + double red = 0.5 + ln(moveCount) * ln(depth / 2) / 6.0; + if (red >= 1.0) + { + ss[ply].reduction = Depth(int(floor(red * int(OnePly)))); + value = -search(pos, ss, -alpha, newDepth-ss[ply].reduction, ply+1, true, threadID); + doFullDepthSearch = (value > alpha); + } } - else - value = alpha + 1; // Just to trigger next condition - if (value > alpha) // Go with full depth non-pv search + if (doFullDepthSearch) // Go with full depth non-pv search { ss[ply].reduction = Depth(0); value = -search(pos, ss, -alpha, newDepth, ply+1, true, threadID); @@ -1269,7 +1307,7 @@ namespace { && idle_thread_exists(threadID) && !AbortSearch && !thread_should_stop(threadID) - && split(pos, ss, ply, &alpha, &beta, &bestValue, VALUE_NONE, VALUE_NONE, + && split(pos, ss, ply, &alpha, &beta, &bestValue, VALUE_NONE, depth, &moveCount, &mp, threadID, true)) break; } @@ -1320,11 +1358,11 @@ namespace { const TTEntry* tte; Move ttMove, move; Depth ext, newDepth; - Value approximateEval, nullValue, value, futilityValue, futilityValueScaled; - bool isCheck, useFutilityPruning, singleReply, moveIsCheck, captureOrPromotion, dangerous; + Value bestValue, staticValue, nullValue, value, futilityValue, futilityValueScaled; + bool isCheck, useFutilityPruning, singleEvasion, moveIsCheck, captureOrPromotion, dangerous; bool mateThreat = false; int moveCount = 0; - Value bestValue = -VALUE_INFINITE; + futilityValue = staticValue = bestValue = value = -VALUE_INFINITE; if (depth < OnePly) return qsearch(pos, ss, beta-1, beta, Depth(0), ply, threadID); @@ -1337,12 +1375,9 @@ namespace { if (AbortSearch || thread_should_stop(threadID)) return Value(0); - if (pos.is_draw()) + if (pos.is_draw() || ply >= PLY_MAX - 1) return VALUE_DRAW; - if (ply >= PLY_MAX - 1) - return pos.is_check() ? quick_evaluate(pos) : evaluate(pos, ei, threadID); - // Mate distance pruning if (value_mated_in(ply) >= beta) return beta; @@ -1364,26 +1399,57 @@ namespace { return value_from_tt(tte->value(), ply); } - approximateEval = quick_evaluate(pos); isCheck = pos.is_check(); + // Calculate depth dependant futility pruning parameters + const int FutilityMoveCountMargin = 3 + (1 << (3 * int(depth) / 8)); + const int PostFutilityValueMargin = 112 * bitScanReverse32(int(depth) * int(depth) / 2); + + // Evaluate the position statically + if (!isCheck) + { + if (tte && (tte->type() & VALUE_TYPE_EVAL)) + staticValue = value_from_tt(tte->value(), ply); + else + { + staticValue = evaluate(pos, ei, threadID); + ss[ply].evalInfo = &ei; + } + + ss[ply].eval = staticValue; + futilityValue = staticValue + PostFutilityValueMargin; //FIXME: Remove me, only for split + staticValue = refine_eval(tte, staticValue, ply); // Enhance accuracy with TT value if possible + + // Store gain statistics + Move m = ss[ply - 1].currentMove; + if ( m != MOVE_NULL + && pos.captured_piece() == NO_PIECE_TYPE + && !move_is_castle(m) + && !move_is_promotion(m)) + MG.store(pos.piece_on(move_to(m)), move_from(m), move_to(m), ss[ply - 1].eval, -ss[ply].eval); + } + + // Post futility pruning + if (staticValue - PostFutilityValueMargin >= beta) + return (staticValue - PostFutilityValueMargin); + // Null move search if ( allowNullmove && depth > OnePly && !isCheck && !value_is_mate(beta) && ok_to_do_nullmove(pos) - && approximateEval >= beta - NullMoveMargin) + && staticValue >= beta - NullMoveMargin) { ss[ply].currentMove = MOVE_NULL; pos.do_null_move(st); // Null move dynamic reduction based on depth - int R = (depth >= 5 * OnePly ? 4 : 3); + int R = 3 + (depth >= 5 * OnePly ? depth / 8 : 0); // Null move dynamic reduction based on value - if (approximateEval - beta > PawnValueMidgame) + if (staticValue - beta > PawnValueMidgame) R++; nullValue = -search(pos, ss, -(beta-1), depth-R*OnePly, ply+1, false, threadID); @@ -1418,13 +1484,14 @@ namespace { } // Null move search not allowed, try razoring else if ( !value_is_mate(beta) + && !isCheck && depth < RazorDepth - && approximateEval < beta - RazorApprMargins[int(depth) - 2] + && staticValue < beta - (NullMoveMargin + 16 * depth) && ss[ply - 1].currentMove != MOVE_NULL && ttMove == MOVE_NONE && !pos.has_pawn_on_7th(pos.side_to_move())) { - Value rbeta = beta - RazorMargins[int(depth) - 2]; + Value rbeta = beta - (NullMoveMargin + 16 * depth); Value v = qsearch(pos, ss, rbeta-1, rbeta, Depth(0), ply, threadID); if (v < rbeta) return v; @@ -1432,7 +1499,7 @@ namespace { // Go with internal iterative deepening if we don't have a TT move if (UseIIDAtNonPVNodes && ttMove == MOVE_NONE && depth >= 8*OnePly && - !isCheck && evaluate(pos, ei, threadID) >= beta - IIDMargin) + !isCheck && ss[ply].eval >= beta - IIDMargin) { search(pos, ss, beta, Min(depth/2, depth-2*OnePly), ply, false, threadID); ttMove = ss[ply].pv[ply]; @@ -1443,17 +1510,8 @@ namespace { // to search all moves. MovePicker mp = MovePicker(pos, ttMove, depth, H, &ss[ply]); CheckInfo ci(pos); - futilityValue = VALUE_NONE; useFutilityPruning = depth < SelectiveDepth && !isCheck; - // Calculate depth dependant futility pruning parameters - const int FutilityMoveCountMargin = 3 + (1 << (3 * int(depth) / 8)); - const int FutilityValueMargin = 112 * bitScanReverse32(int(depth) * int(depth) / 2); - - // Avoid calling evaluate() if we already have the score in TT - if (tte && (tte->type() & VALUE_TYPE_EVAL)) - futilityValue = value_from_tt(tte->value(), ply) + FutilityValueMargin; - // Loop through all legal moves until no moves remain or a beta cutoff occurs while ( bestValue < beta && (move = mp.get_next_move()) != MOVE_NONE @@ -1464,17 +1522,16 @@ namespace { if (move == excludedMove) continue; - singleReply = (isCheck && mp.number_of_evasions() == 1); moveIsCheck = pos.move_is_check(move, ci); + singleEvasion = (isCheck && mp.number_of_evasions() == 1); captureOrPromotion = pos.move_is_capture_or_promotion(move); // Decide the new search depth - ext = extension(pos, move, false, captureOrPromotion, moveIsCheck, singleReply, mateThreat, &dangerous); + ext = extension(pos, move, false, captureOrPromotion, moveIsCheck, singleEvasion, mateThreat, &dangerous); - // We want to extend the TT move if it is much better then remaining ones. - // To verify this we do a reduced search on all the other moves but the ttMove, - // if result is lower then TT value minus a margin then we assume ttMove is the - // only one playable. It is a kind of relaxed single reply extension. + // Singular extension search. We extend the TT move if its value is much better than + // its siblings. 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. if ( depth >= 8 * OnePly && tte && move == tte->move() @@ -1489,8 +1546,6 @@ namespace { { Value excValue = search(pos, ss, ttValue - SingleReplyMargin, depth / 2, ply, false, threadID, move); - // If search result is well below the foreseen score of the ttMove then we - // assume ttMove is the only one realistically playable and we extend it. if (excValue < ttValue - SingleReplyMargin) ext = OnePly; } @@ -1501,10 +1556,33 @@ namespace { // Update current move movesSearched[moveCount++] = ss[ply].currentMove = move; + // Futility pruning for captures + Color them = opposite_color(pos.side_to_move()); + + if ( useFutilityPruning + && !dangerous + && pos.move_is_capture(move) + && !pos.move_is_check(move, ci) + && !move_is_promotion(move) + && move != ttMove + && !move_is_ep(move) + && (pos.type_of_piece_on(move_to(move)) != PAWN || !pos.pawn_is_passed(them, move_to(move)))) // Do not prune passed pawn captures + { + int preFutilityValueMargin = 0; + + if (newDepth >= OnePly) + preFutilityValueMargin = 112 * bitScanReverse32(int(newDepth) * int(newDepth) / 2); + + if (ss[ply].eval + pos.endgame_value_of_piece_on(move_to(move)) + preFutilityValueMargin + ei.futilityMargin + 90 < beta) + continue; + } + + // Futility pruning if ( useFutilityPruning && !dangerous && !captureOrPromotion + && !move_is_castle(move) && move != ttMove) { // Move count based pruning @@ -1514,10 +1592,20 @@ namespace { continue; // Value based pruning - if (futilityValue == VALUE_NONE) - futilityValue = evaluate(pos, ei, threadID) + FutilityValueMargin; + Depth predictedDepth = newDepth; + + //FIXME HACK: awful code duplication + double red = 0.5 + ln(moveCount) * ln(depth / 2) / 3.0; + if (red >= 1.0) + predictedDepth -= int(floor(red * int(OnePly))); + + int preFutilityValueMargin = 0; + if (predictedDepth >= OnePly) + preFutilityValueMargin = 112 * bitScanReverse32(int(predictedDepth) * int(predictedDepth) / 2); - futilityValueScaled = futilityValue - moveCount * IncrementalFutilityMargin; + preFutilityValueMargin += MG.retrieve(pos.piece_on(move_from(move)), move_from(move), move_to(move)) + 45; + + futilityValueScaled = ss[ply].eval + preFutilityValueMargin - moveCount * IncrementalFutilityMargin; if (futilityValueScaled < beta) { @@ -1532,20 +1620,25 @@ namespace { // Try to reduce non-pv search depth by one ply if move seems not problematic, // if the move fails high will be re-searched at full depth. + bool doFullDepthSearch = true; + if ( depth >= 3*OnePly - && moveCount >= LMRNonPVMoves && !dangerous && !captureOrPromotion && !move_is_castle(move) - && !move_is_killer(move, ss[ply])) + && !move_is_killer(move, ss[ply]) + /* && move != ttMove*/) { - ss[ply].reduction = OnePly; - value = -search(pos, ss, -(beta-1), newDepth-OnePly, ply+1, true, threadID); + double red = 0.5 + ln(moveCount) * ln(depth / 2) / 3.0; + if (red >= 1.0) + { + ss[ply].reduction = Depth(int(floor(red * int(OnePly)))); + value = -search(pos, ss, -(beta-1), newDepth-ss[ply].reduction, ply+1, true, threadID); + doFullDepthSearch = (value >= beta); + } } - else - value = beta; // Just to trigger next condition - if (value >= beta) // Go with full depth non-pv search + if (doFullDepthSearch) // Go with full depth non-pv search { ss[ply].reduction = Depth(0); value = -search(pos, ss, -(beta-1), newDepth, ply+1, true, threadID); @@ -1573,14 +1666,14 @@ namespace { && idle_thread_exists(threadID) && !AbortSearch && !thread_should_stop(threadID) - && split(pos, ss, ply, &beta, &beta, &bestValue, futilityValue, approximateEval, + && split(pos, ss, ply, &beta, &beta, &bestValue, futilityValue, //FIXME: SMP & futilityValue depth, &moveCount, &mp, threadID, false)) break; } - // All legal moves have been searched. A special case: If there were + // All legal moves have been searched. A special case: If there were // no legal moves, it must be mate or stalemate. - if (moveCount == 0) + if (!moveCount) return excludedMove ? beta - 1 : (pos.is_check() ? value_mated_in(ply) : VALUE_DRAW); // If the search is not aborted, update the transposition table, @@ -1594,12 +1687,13 @@ namespace { { BetaCounter.add(pos.side_to_move(), depth, threadID); move = ss[ply].pv[ply]; + TT.store(posKey, value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, depth, move); if (!pos.move_is_capture_or_promotion(move)) { update_history(pos, move, depth, movesSearched, moveCount); update_killers(move, ss[ply]); } - TT.store(posKey, value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, depth, move); + } assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE); @@ -1624,8 +1718,8 @@ namespace { EvalInfo ei; StateInfo st; Move ttMove, move; - Value staticValue, bestValue, value, futilityValue; - bool isCheck, enoughMaterial, moveIsCheck; + Value staticValue, bestValue, value, futilityBase, futilityValue; + bool isCheck, enoughMaterial, moveIsCheck, evasionPrunable; const TTEntry* tte = NULL; int moveCount = 0; bool pvNode = (beta - alpha != 1); @@ -1638,41 +1732,44 @@ namespace { if (AbortSearch || thread_should_stop(threadID)) return Value(0); - if (pos.is_draw()) + if (pos.is_draw() || ply >= PLY_MAX - 1) return VALUE_DRAW; - // Transposition table lookup, only when not in PV - if (!pvNode) + // Transposition table lookup. At PV nodes, we don't use the TT for + // pruning, but only for move ordering. + tte = TT.retrieve(pos.get_key()); + ttMove = (tte ? tte->move() : MOVE_NONE); + + if (!pvNode && tte && ok_to_use_TT(tte, depth, beta, ply)) { - tte = TT.retrieve(pos.get_key()); - if (tte && ok_to_use_TT(tte, depth, beta, ply)) - { - assert(tte->type() != VALUE_TYPE_EVAL); + assert(tte->type() != VALUE_TYPE_EVAL); - return value_from_tt(tte->value(), ply); - } + ss[ply].currentMove = ttMove; // Can be MOVE_NONE + return value_from_tt(tte->value(), ply); } - ttMove = (tte ? tte->move() : MOVE_NONE); isCheck = pos.is_check(); - ei.futilityMargin = Value(0); // Manually initialize futilityMargin // Evaluate the position statically if (isCheck) staticValue = -VALUE_INFINITE; - else if (tte && (tte->type() & VALUE_TYPE_EVAL)) - { - // Use the cached evaluation score if possible - assert(ei.futilityMargin == Value(0)); - staticValue = value_from_tt(tte->value(), ply); - } else staticValue = evaluate(pos, ei, threadID); - if (ply >= PLY_MAX - 1) - return pos.is_check() ? quick_evaluate(pos) : evaluate(pos, ei, threadID); + if (!isCheck) + { + ss[ply].eval = staticValue; + // Store gain statistics + Move m = ss[ply - 1].currentMove; + if ( m != MOVE_NULL + && pos.captured_piece() == NO_PIECE_TYPE + && !move_is_castle(m) + && !move_is_promotion(m)) + MG.store(pos.piece_on(move_to(m)), move_from(m), move_to(m), ss[ply - 1].eval, -ss[ply].eval); + } + // Initialize "stand pat score", and return it immediately if it is // at least beta. @@ -1690,12 +1787,17 @@ namespace { if (bestValue > alpha) alpha = bestValue; + // If we are near beta then try to get a cutoff pushing checks a bit further + bool deepChecks = depth == -OnePly && staticValue >= beta - PawnValueMidgame / 8; + // Initialize a MovePicker object for the current position, and prepare - // to search the moves. Because the depth is <= 0 here, only captures, - // queen promotions and checks (only if depth == 0) will be generated. - MovePicker mp = MovePicker(pos, ttMove, depth, H); + // to search the moves. Because the depth is <= 0 here, only captures, + // queen promotions and checks (only if depth == 0 or depth == -OnePly + // and we are near beta) will be generated. + MovePicker mp = MovePicker(pos, ttMove, deepChecks ? Depth(0) : depth, H); CheckInfo ci(pos); enoughMaterial = pos.non_pawn_material(pos.side_to_move()) > RookValueMidgame; + futilityBase = staticValue + FutilityMarginQS + ei.futilityMargin; // Loop through the moves until no moves remain or a beta cutoff // occurs. @@ -1704,11 +1806,12 @@ namespace { { assert(move_is_ok(move)); + moveIsCheck = pos.move_is_check(move, ci); + + // Update current move moveCount++; ss[ply].currentMove = move; - moveIsCheck = pos.move_is_check(move, ci); - // Futility pruning if ( enoughMaterial && !isCheck @@ -1718,12 +1821,9 @@ namespace { && !move_is_promotion(move) && !pos.move_is_passed_pawn_push(move)) { - futilityValue = staticValue - + Max(pos.midgame_value_of_piece_on(move_to(move)), - pos.endgame_value_of_piece_on(move_to(move))) - + (move_is_ep(move) ? PawnValueEndgame : Value(0)) - + FutilityMarginQS - + ei.futilityMargin; + futilityValue = futilityBase + + pos.endgame_value_of_piece_on(move_to(move)) + + (move_is_ep(move) ? PawnValueEndgame : Value(0)); if (futilityValue < alpha) { @@ -1733,8 +1833,15 @@ namespace { } } - // Don't search captures and checks with negative SEE values - if ( !isCheck + // Detect blocking evasions that are candidate to be pruned + evasionPrunable = isCheck + && bestValue != -VALUE_INFINITE + && !pos.move_is_capture(move) + && pos.type_of_piece_on(move_from(move)) != KING + && !pos.can_castle(pos.side_to_move()); + + // Don't search moves with negative SEE values + if ( (!isCheck || evasionPrunable) && move != ttMove && !move_is_promotion(move) && pos.see_sign(move) < 0) @@ -1759,31 +1866,31 @@ namespace { } } - // All legal moves have been searched. A special case: If we're in check + // All legal moves have been searched. A special case: If we're in check // and no legal moves were found, it is checkmate. if (!moveCount && pos.is_check()) // Mate! return value_mated_in(ply); - assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE); - // Update transposition table - move = ss[ply].pv[ply]; - if (!pvNode) + Depth d = (depth == Depth(0) ? Depth(0) : Depth(-1)); + if (bestValue < beta) { - // If bestValue isn't changed it means it is still the static evaluation of - // the node, so keep this info to avoid a future costly evaluation() call. + // If bestValue isn't changed it means it is still the static evaluation + // of the node, so keep this info to avoid a future evaluation() call. ValueType type = (bestValue == staticValue && !ei.futilityMargin ? VALUE_TYPE_EV_UP : VALUE_TYPE_UPPER); - Depth d = (depth == Depth(0) ? Depth(0) : Depth(-1)); + TT.store(pos.get_key(), value_to_tt(bestValue, ply), type, d, MOVE_NONE); + } + else + { + move = ss[ply].pv[ply]; + TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, d, move); - if (bestValue < beta) - TT.store(pos.get_key(), value_to_tt(bestValue, ply), type, d, MOVE_NONE); - else - TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, d, move); + // Update killers only for good checking moves + if (!pos.move_is_capture_or_promotion(move)) + update_killers(move, ss[ply]); } - // Update killers only for good check moves - if (alpha >= beta && !pos.move_is_capture_or_promotion(move)) - update_killers(move, ss[ply]); + assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE); return bestValue; } @@ -1802,17 +1909,16 @@ namespace { assert(threadID >= 0 && threadID < ActiveThreads); assert(ActiveThreads > 1); - Position pos = Position(sp->pos); + Position pos(*sp->pos); CheckInfo ci(pos); SearchStack* ss = sp->sstack[threadID]; - Value value; + Value value = -VALUE_INFINITE; Move move; bool isCheck = pos.is_check(); bool useFutilityPruning = sp->depth < SelectiveDepth && !isCheck; const int FutilityMoveCountMargin = 3 + (1 << (3 * int(sp->depth) / 8)); - const int FutilityValueMargin = 112 * bitScanReverse32(int(sp->depth) * int(sp->depth) / 2); while ( sp->bestValue < sp->beta && !thread_should_stop(threadID) @@ -1846,12 +1952,6 @@ namespace { continue; // Value based pruning - if (sp->futilityValue == VALUE_NONE) - { - EvalInfo ei; - sp->futilityValue = evaluate(pos, ei, threadID) + FutilityValueMargin; - } - Value futilityValueScaled = sp->futilityValue - moveCount * IncrementalFutilityMargin; if (futilityValueScaled < sp->beta) @@ -1873,19 +1973,23 @@ namespace { // Try to reduce non-pv search depth by one ply if move seems not problematic, // if the move fails high will be re-searched at full depth. + bool doFullDepthSearch = true; + if ( !dangerous - && moveCount >= LMRNonPVMoves && !captureOrPromotion && !move_is_castle(move) && !move_is_killer(move, ss[sp->ply])) { - ss[sp->ply].reduction = OnePly; - value = -search(pos, ss, -(sp->beta-1), newDepth - OnePly, sp->ply+1, true, threadID); + double red = 0.5 + ln(moveCount) * ln(sp->depth / 2) / 3.0; + if (red >= 1.0) + { + ss[sp->ply].reduction = Depth(int(floor(red * int(OnePly)))); + value = -search(pos, ss, -(sp->beta-1), newDepth-ss[sp->ply].reduction, sp->ply+1, true, threadID); + doFullDepthSearch = (value >= sp->beta); + } } - else - value = sp->beta; // Just to trigger next condition - if (value >= sp->beta) // Go with full depth non-pv search + if (doFullDepthSearch) // Go with full depth non-pv search { ss[sp->ply].reduction = Depth(0); value = -search(pos, ss, -(sp->beta - 1), newDepth, sp->ply+1, true, threadID); @@ -1947,10 +2051,10 @@ namespace { assert(threadID >= 0 && threadID < ActiveThreads); assert(ActiveThreads > 1); - Position pos = Position(sp->pos); + Position pos(*sp->pos); CheckInfo ci(pos); SearchStack* ss = sp->sstack[threadID]; - Value value; + Value value = -VALUE_INFINITE; Move move; while ( sp->alpha < sp->beta @@ -1979,34 +2083,47 @@ namespace { // Try to reduce non-pv search depth by one ply if move seems not problematic, // if the move fails high will be re-searched at full depth. + bool doFullDepthSearch = true; + if ( !dangerous - && moveCount >= LMRPVMoves && !captureOrPromotion && !move_is_castle(move) && !move_is_killer(move, ss[sp->ply])) { - ss[sp->ply].reduction = OnePly; - value = -search(pos, ss, -sp->alpha, newDepth - OnePly, sp->ply+1, true, threadID); + double red = 0.5 + ln(moveCount) * ln(sp->depth / 2) / 6.0; + if (red >= 1.0) + { + Value localAlpha = sp->alpha; + ss[sp->ply].reduction = Depth(int(floor(red * int(OnePly)))); + value = -search(pos, ss, -localAlpha, newDepth-ss[sp->ply].reduction, sp->ply+1, true, threadID); + doFullDepthSearch = (value > localAlpha); + } } - else - value = sp->alpha + 1; // Just to trigger next condition - if (value > sp->alpha) // Go with full depth non-pv search + if (doFullDepthSearch) // Go with full depth non-pv search { + Value localAlpha = sp->alpha; ss[sp->ply].reduction = Depth(0); - value = -search(pos, ss, -sp->alpha, newDepth, sp->ply+1, true, threadID); + value = -search(pos, ss, -localAlpha, newDepth, sp->ply+1, true, threadID); - if (value > sp->alpha && value < sp->beta) + if (value > localAlpha && value < sp->beta) { // When the search fails high at ply 1 while searching the first - // move at the root, set the flag failHighPly1. This is used for + // move at the root, set the flag failHighPly1. This is used for // time managment: We don't want to stop the search early in // such cases, because resolving the fail high at ply 1 could // result in a big drop in score at the root. if (sp->ply == 1 && RootMoveNumber == 1) Threads[threadID].failHighPly1 = true; - value = -search_pv(pos, ss, -sp->beta, -sp->alpha, newDepth, sp->ply+1, threadID); + // If another thread has failed high then sp->alpha has been increased + // to be higher or equal then beta, if so, avoid to start a PV search. + localAlpha = sp->alpha; + if (localAlpha < sp->beta) + value = -search_pv(pos, ss, -sp->beta, -localAlpha, newDepth, sp->ply+1, threadID); + else + assert(thread_should_stop(threadID)); + Threads[threadID].failHighPly1 = false; } } @@ -2018,35 +2135,40 @@ namespace { break; // New best move? - lock_grab(&(sp->lock)); - if (value > sp->bestValue && !thread_should_stop(threadID)) + if (value > sp->bestValue) // Less then 2% of cases { - sp->bestValue = value; - if (value > sp->alpha) + lock_grab(&(sp->lock)); + if (value > sp->bestValue && !thread_should_stop(threadID)) { - sp->alpha = value; - sp_update_pv(sp->parentSstack, ss, sp->ply); - if (value == value_mate_in(sp->ply + 1)) - ss[sp->ply].mateKiller = move; - - if (value >= sp->beta) + sp->bestValue = value; + if (value > sp->alpha) { - for (int i = 0; i < ActiveThreads; i++) - if (i != threadID && (i == sp->master || sp->slaves[i])) - Threads[i].stop = true; + // Ask threads to stop before to modify sp->alpha + if (value >= sp->beta) + { + for (int i = 0; i < ActiveThreads; i++) + if (i != threadID && (i == sp->master || sp->slaves[i])) + Threads[i].stop = true; - sp->finished = true; + sp->finished = true; + } + + sp->alpha = value; + + sp_update_pv(sp->parentSstack, ss, sp->ply); + if (value == value_mate_in(sp->ply + 1)) + ss[sp->ply].mateKiller = move; } - } - // If we are at ply 1, and we are searching the first root move at - // ply 0, set the 'Problem' variable if the score has dropped a lot - // (from the computer's point of view) since the previous iteration. - if ( sp->ply == 1 - && Iteration >= 2 - && -value <= IterationInfo[Iteration-1].value - ProblemMargin) - Problem = true; + // If we are at ply 1, and we are searching the first root move at + // ply 0, set the 'Problem' variable if the score has dropped a lot + // (from the computer's point of view) since the previous iteration. + if ( sp->ply == 1 + && Iteration >= 2 + && -value <= IterationInfo[Iteration-1].value - ProblemMargin) + Problem = true; + } + lock_release(&(sp->lock)); } - lock_release(&(sp->lock)); } lock_grab(&(sp->lock)); @@ -2091,30 +2213,9 @@ namespace { } - /// The RootMove class - - // Constructor - - RootMove::RootMove() { - nodes = cumulativeNodes = ourBeta = theirBeta = 0ULL; - } - - // 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 a higher score, or if the moves - // have equal score but m1 has the higher node count. - - bool RootMove::operator<(const RootMove& m) { - - if (score != m.score) - return (score < m.score); - - return theirBeta <= m.theirBeta; - } - /// The RootMoveList class - // Constructor + // RootMoveList c'tor RootMoveList::RootMoveList(Position& pos, Move searchMoves[]) : count(0) { @@ -2152,56 +2253,37 @@ namespace { } - // Simple accessor methods for the RootMoveList class - - inline Move RootMoveList::get_move(int moveNum) const { - return moves[moveNum].move; - } - - inline Value RootMoveList::get_move_score(int moveNum) const { - return moves[moveNum].score; - } + // RootMoveList simple methods definitions - inline void RootMoveList::set_move_score(int moveNum, Value score) { - moves[moveNum].score = score; - } + void RootMoveList::set_move_nodes(int moveNum, int64_t nodes) { - inline void RootMoveList::set_move_nodes(int moveNum, int64_t nodes) { moves[moveNum].nodes = nodes; moves[moveNum].cumulativeNodes += nodes; } - inline void RootMoveList::set_beta_counters(int moveNum, int64_t our, int64_t their) { + void RootMoveList::set_beta_counters(int moveNum, int64_t our, int64_t their) { + moves[moveNum].ourBeta = our; moves[moveNum].theirBeta = their; } void RootMoveList::set_move_pv(int moveNum, const Move pv[]) { - int j; - for(j = 0; pv[j] != MOVE_NONE; j++) - moves[moveNum].pv[j] = pv[j]; - moves[moveNum].pv[j] = MOVE_NONE; - } - inline Move RootMoveList::get_move_pv(int moveNum, int i) const { - return moves[moveNum].pv[i]; - } + int j; - inline int64_t RootMoveList::get_move_cumulative_nodes(int moveNum) const { - return moves[moveNum].cumulativeNodes; - } + for (j = 0; pv[j] != MOVE_NONE; j++) + moves[moveNum].pv[j] = pv[j]; - inline int RootMoveList::move_count() const { - return count; + moves[moveNum].pv[j] = MOVE_NONE; } // RootMoveList::sort() sorts the root move list at the beginning of a new // iteration. - inline void RootMoveList::sort() { + void RootMoveList::sort() { - sort_multipv(count - 1); // all items + sort_multipv(count - 1); // Sort all items } @@ -2211,20 +2293,22 @@ namespace { void RootMoveList::sort_multipv(int n) { - for (int i = 1; i <= n; i++) + int i,j; + + for (i = 1; i <= n; i++) { - RootMove rm = moves[i]; - int j; - for (j = i; j > 0 && moves[j-1] < rm; j--) - moves[j] = moves[j-1]; - moves[j] = rm; + RootMove rm = moves[i]; + for (j = i; j > 0 && moves[j - 1] < rm; j--) + moves[j] = moves[j - 1]; + + moves[j] = rm; } } // init_node() is called at the beginning of all the search functions - // (search(), search_pv(), qsearch(), and so on) and initializes the search - // stack object corresponding to the current node. Once every + // (search(), search_pv(), qsearch(), and so on) and initializes the + // search stack object corresponding to the current node. Once every // NodesBetweenPolls nodes, init_node() also calls poll(), which polls // for user input and checks whether it is time to stop the search. @@ -2245,48 +2329,56 @@ namespace { } } ss[ply].init(ply); - ss[ply+2].initKillers(); + ss[ply + 2].initKillers(); if (Threads[threadID].printCurrentLine) print_current_line(ss, ply, threadID); } - // update_pv() is called whenever a search returns a value > alpha. It - // updates the PV in the SearchStack object corresponding to the current - // node. + // update_pv() is called whenever a search returns a value > alpha. + // It updates the PV in the SearchStack object corresponding to the + // current node. void update_pv(SearchStack ss[], int ply) { + assert(ply >= 0 && ply < PLY_MAX); - ss[ply].pv[ply] = ss[ply].currentMove; int p; - for(p = ply + 1; ss[ply+1].pv[p] != MOVE_NONE; p++) - ss[ply].pv[p] = ss[ply+1].pv[p]; + + ss[ply].pv[ply] = ss[ply].currentMove; + + for (p = ply + 1; ss[ply + 1].pv[p] != MOVE_NONE; p++) + ss[ply].pv[p] = ss[ply + 1].pv[p]; + ss[ply].pv[p] = MOVE_NONE; } - // sp_update_pv() is a variant of update_pv for use at split points. The + // sp_update_pv() is a variant of update_pv for use at split points. The // difference between the two functions is that sp_update_pv also updates // the PV at the parent node. void sp_update_pv(SearchStack* pss, SearchStack ss[], int ply) { + assert(ply >= 0 && ply < PLY_MAX); - ss[ply].pv[ply] = pss[ply].pv[ply] = ss[ply].currentMove; int p; - for(p = ply + 1; ss[ply+1].pv[p] != MOVE_NONE; p++) - ss[ply].pv[p] = pss[ply].pv[p] = ss[ply+1].pv[p]; + + ss[ply].pv[ply] = pss[ply].pv[ply] = ss[ply].currentMove; + + for (p = ply + 1; ss[ply + 1].pv[p] != MOVE_NONE; p++) + ss[ply].pv[p] = pss[ply].pv[p] = ss[ply + 1].pv[p]; + ss[ply].pv[p] = pss[ply].pv[p] = MOVE_NONE; } // connected_moves() tests whether two moves are 'connected' in the sense // that the first move somehow made the second move possible (for instance - // if the moving piece is the same in both moves). The first move is - // assumed to be the move that was made to reach the current position, while - // the second move is assumed to be a move from the current position. + // if the moving piece is the same in both moves). The first move is assumed + // to be the move that was made to reach the current position, while the + // second move is assumed to be a move from the current position. bool connected_moves(const Position& pos, Move m1, Move m2) { @@ -2316,36 +2408,23 @@ namespace { && bit_is_set(squares_between(f2, t2), f1)) return true; - // Case 4: The destination square for m2 is attacked by the moving piece in m1 + // Case 4: The destination square for m2 is defended by the moving piece in m1 p = pos.piece_on(t1); if (bit_is_set(pos.attacks_from(p, t1), t2)) return true; // Case 5: Discovered check, checking piece is the piece moved in m1 - if ( piece_is_slider(p) - && bit_is_set(squares_between(t1, pos.king_square(pos.side_to_move())), f2) + if ( piece_is_slider(p) + && bit_is_set(squares_between(t1, pos.king_square(pos.side_to_move())), f2) && !bit_is_set(squares_between(t1, pos.king_square(pos.side_to_move())), t2)) { - Bitboard occ = pos.occupied_squares(); - Color us = pos.side_to_move(); - Square ksq = pos.king_square(us); - clear_bit(&occ, f2); - if (type_of_piece(p) == BISHOP) - { - if (bit_is_set(bishop_attacks_bb(ksq, occ), t1)) - return true; - } - else if (type_of_piece(p) == ROOK) - { - if (bit_is_set(rook_attacks_bb(ksq, occ), t1)) - return true; - } - else - { - assert(type_of_piece(p) == QUEEN); - if (bit_is_set(queen_attacks_bb(ksq, occ), t1)) - return true; - } + // discovered_check_candidates() works also if the Position's side to + // move is the opposite of the checking piece. + Color them = opposite_color(pos.side_to_move()); + Bitboard dcCandidates = pos.discovered_check_candidates(them); + + if (bit_is_set(dcCandidates, f2)) + return true; } return false; } @@ -2378,27 +2457,27 @@ namespace { // extension() decides whether a move should be searched with normal depth, - // or with extended depth. Certain classes of moves (checking moves, in + // or with extended depth. Certain classes of moves (checking moves, in // particular) are searched with bigger depth than ordinary moves and in // any case are marked as 'dangerous'. Note that also if a move is not // extended, as example because the corresponding UCI option is set to zero, // the move is marked as 'dangerous' so, at least, we avoid to prune it. Depth extension(const Position& pos, Move m, bool pvNode, bool captureOrPromotion, - bool check, bool singleReply, bool mateThreat, bool* dangerous) { + bool moveIsCheck, bool singleEvasion, bool mateThreat, bool* dangerous) { assert(m != MOVE_NONE); Depth result = Depth(0); - *dangerous = check | singleReply | mateThreat; + *dangerous = moveIsCheck | singleEvasion | mateThreat; if (*dangerous) { - if (check) + if (moveIsCheck) result += CheckExtension[pvNode]; - if (singleReply) - result += SingleReplyExtension[pvNode]; + if (singleEvasion) + result += SingleEvasionExtension[pvNode]; if (mateThreat) result += MateThreatExtension[pvNode]; @@ -2444,11 +2523,11 @@ namespace { // ok_to_do_nullmove() looks at the current position and decides whether - // doing a 'null move' should be allowed. In order to avoid zugzwang + // doing a 'null move' should be allowed. In order to avoid zugzwang // problems, null moves are not allowed when the side to move has very - // little material left. Currently, the test is a bit too simple: Null - // moves are avoided only when the side to move has only pawns left. It's - // probably a good idea to avoid null moves in at least some more + // little material left. Currently, the test is a bit too simple: Null + // moves are avoided only when the side to move has only pawns left. + // It's probably a good idea to avoid null moves in at least some more // complicated endgames, e.g. KQ vs KR. FIXME bool ok_to_do_nullmove(const Position& pos) { @@ -2457,7 +2536,7 @@ namespace { } - // ok_to_prune() tests whether it is safe to forward prune a move. Only + // ok_to_prune() tests whether it is safe to forward prune a move. Only // non-tactical moves late in the move list close to the leaves are // candidates for pruning. @@ -2471,34 +2550,30 @@ namespace { Square mfrom, mto, tfrom, tto; + // Prune if there isn't any threat move + if (threat == MOVE_NONE) + return true; + mfrom = move_from(m); mto = move_to(m); tfrom = move_from(threat); tto = move_to(threat); - // Case 1: Castling moves are never pruned - if (move_is_castle(m)) + // Case 1: Don't prune moves which move the threatened piece + if (mfrom == tto) return false; - // Case 2: Don't prune moves which move the threatened piece - if (!PruneEscapeMoves && threat != MOVE_NONE && mfrom == tto) - return false; - - // Case 3: If the threatened piece has value less than or equal to the + // 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. - if ( !PruneDefendingMoves - && threat != MOVE_NONE - && pos.move_is_capture(threat) + 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) && pos.move_attacks_square(m, tto)) return false; - // Case 4: If the moving piece in the threatened move is a slider, don't + // Case 3: If the moving piece in the threatened move is a slider, don't // prune safe moves which block its ray. - if ( !PruneBlockingMoves - && threat != MOVE_NONE - && piece_is_slider(pos.piece_on(tfrom)) + if ( piece_is_slider(pos.piece_on(tfrom)) && bit_is_set(squares_between(tfrom, tto), mto) && pos.see_sign(m) >= 0) return false; @@ -2523,19 +2598,41 @@ namespace { } + // refine_eval() returns the transposition table score if + // possible otherwise falls back on static position evaluation. + + Value refine_eval(const TTEntry* tte, Value defaultEval, int ply) { + + if (!tte) + return defaultEval; + + Value v = value_from_tt(tte->value(), ply); + + if ( (is_lower_bound(tte->type()) && v >= defaultEval) + || (is_upper_bound(tte->type()) && v < defaultEval)) + return v; + + return defaultEval; + } + // update_history() registers a good move that produced a beta-cutoff // in history and marks as failures all the other moves of that ply. - void update_history(const Position& pos, Move m, Depth depth, + void update_history(const Position& pos, Move move, Depth depth, Move movesSearched[], int moveCount) { - H.success(pos.piece_on(move_from(m)), move_to(m), depth); + Move m; + + H.success(pos.piece_on(move_from(move)), move_to(move), depth); for (int i = 0; i < moveCount - 1; i++) { - assert(m != movesSearched[i]); - if (!pos.move_is_capture_or_promotion(movesSearched[i])) - H.failure(pos.piece_on(move_from(movesSearched[i])), move_to(movesSearched[i]), depth); + m = movesSearched[i]; + + assert(m != move); + + if (!pos.move_is_capture_or_promotion(m)) + H.failure(pos.piece_on(move_from(m)), move_to(m), depth); } } @@ -2557,11 +2654,11 @@ namespace { // fail_high_ply_1() checks if some thread is currently resolving a fail // high at ply 1 at the node below the first root node. This information - // is used for time managment. + // is used for time management. bool fail_high_ply_1() { - for(int i = 0; i < ActiveThreads; i++) + for (int i = 0; i < ActiveThreads; i++) if (Threads[i].failHighPly1) return true; @@ -2573,6 +2670,7 @@ namespace { // since the beginning of the current search. int current_search_time() { + return get_system_time() - SearchStartTime; } @@ -2580,12 +2678,13 @@ namespace { // nps() computes the current nodes/second count. int nps() { + int t = current_search_time(); - return (t > 0)? int((nodes_searched() * 1000) / t) : 0; + return (t > 0 ? int((nodes_searched() * 1000) / t) : 0); } - // poll() performs two different functions: It polls for user input, and it + // poll() performs two different functions: It polls for user input, and it // looks at the time consumed so far and decides if it's time to abort the // search. @@ -2599,6 +2698,7 @@ namespace { { // We are line oriented, don't read single chars std::string command; + if (!std::getline(std::cin, command)) command = "quit"; @@ -2617,6 +2717,7 @@ namespace { else if (command == "ponderhit") ponderhit(); } + // Print search information if (t < 1000) lastInfoTime = 0; @@ -2630,28 +2731,41 @@ namespace { { lastInfoTime = t; lock_grab(&IOLock); + if (dbg_show_mean) dbg_print_mean(); if (dbg_show_hit_rate) dbg_print_hit_rate(); - std::cout << "info nodes " << nodes_searched() << " nps " << nps() - << " time " << t << " hashfull " << TT.full() << std::endl; + cout << "info nodes " << nodes_searched() << " nps " << nps() + << " time " << t << " hashfull " << TT.full() << endl; + lock_release(&IOLock); + if (ShowCurrentLine) Threads[0].printCurrentLine = true; } + // Should we stop the search? if (PonderSearch) return; - bool overTime = t > AbsoluteMaxSearchTime - || (RootMoveNumber == 1 && t > MaxSearchTime + ExtraSearchTime && !FailLow) //FIXME: We are not checking any problem flags, BUG? - || ( !FailHigh && !FailLow && !fail_high_ply_1() && !Problem - && t > 6*(MaxSearchTime + ExtraSearchTime)); + bool stillAtFirstMove = RootMoveNumber == 1 + && !FailLow + && t > MaxSearchTime + ExtraSearchTime; + + bool noProblemFound = !FailHigh + && !FailLow + && !fail_high_ply_1() + && !Problem + && t > 6 * (MaxSearchTime + ExtraSearchTime); - if ( (Iteration >= 3 && (!InfiniteSearch && overTime)) + bool noMoreTime = t > AbsoluteMaxSearchTime + || stillAtFirstMove //FIXME: We are not checking any problem flags, BUG? + || noProblemFound; + + if ( (Iteration >= 3 && UseTimeManagement && noMoreTime) || (ExactMaxTime && t >= ExactMaxTime) || (Iteration >= 3 && MaxNodes && nodes_searched() >= MaxNodes)) AbortSearch = true; @@ -2666,19 +2780,28 @@ namespace { int t = current_search_time(); PonderSearch = false; - if (Iteration >= 3 && - (!InfiniteSearch && (StopOnPonderhit || - t > AbsoluteMaxSearchTime || - (RootMoveNumber == 1 && - t > MaxSearchTime + ExtraSearchTime && !FailLow) || - (!FailHigh && !FailLow && !fail_high_ply_1() && !Problem && - t > 6*(MaxSearchTime + ExtraSearchTime))))) - AbortSearch = true; + + bool stillAtFirstMove = RootMoveNumber == 1 + && !FailLow + && t > MaxSearchTime + ExtraSearchTime; + + bool noProblemFound = !FailHigh + && !FailLow + && !fail_high_ply_1() + && !Problem + && t > 6 * (MaxSearchTime + ExtraSearchTime); + + bool noMoreTime = t > AbsoluteMaxSearchTime + || stillAtFirstMove + || noProblemFound; + + if (Iteration >= 3 && UseTimeManagement && (noMoreTime || StopOnPonderhit)) + AbortSearch = true; } // print_current_line() prints the current line of search for a given - // thread. Called when the UCI option UCI_ShowCurrLine is 'true'. + // thread. Called when the UCI option UCI_ShowCurrLine is 'true'. void print_current_line(SearchStack ss[], int ply, int threadID) { @@ -2688,11 +2811,11 @@ namespace { if (!Threads[threadID].idle) { lock_grab(&IOLock); - std::cout << "info currline " << (threadID + 1); + cout << "info currline " << (threadID + 1); for (int p = 0; p < ply; p++) - std::cout << " " << ss[p].currentMove; + cout << " " << ss[p].currentMove; - std::cout << std::endl; + cout << endl; lock_release(&IOLock); } Threads[threadID].printCurrentLine = false; @@ -2714,8 +2837,8 @@ namespace { // wait_for_stop_or_ponderhit() is called when the maximum depth is reached - // while the program is pondering. The point is to work around a wrinkle in - // the UCI protocol: When pondering, the engine is not allowed to give a + // while the program is pondering. The point is to work around a wrinkle in + // the UCI protocol: When pondering, the engine is not allowed to give a // "bestmove" before the GUI sends it a "stop" or "ponderhit" command. // We simply wait here until one of these commands is sent, and return, // after which the bestmove and pondermove will be printed (in id_loop()). @@ -2745,41 +2868,50 @@ namespace { // object for which the current thread is the master. void idle_loop(int threadID, SplitPoint* waitSp) { + assert(threadID >= 0 && threadID < THREAD_MAX); Threads[threadID].running = true; - while(true) { - if(AllThreadsShouldExit && threadID != 0) - break; + while (true) + { + if (AllThreadsShouldExit && threadID != 0) + break; + + // If we are not thinking, wait for a condition to be signaled + // instead of wasting CPU time polling for work. + while (threadID != 0 && (Idle || threadID >= ActiveThreads)) + { - // If we are not thinking, wait for a condition to be signaled instead - // of wasting CPU time polling for work: - while(threadID != 0 && (Idle || threadID >= ActiveThreads)) { #if !defined(_MSC_VER) - pthread_mutex_lock(&WaitLock); - if(Idle || threadID >= ActiveThreads) - pthread_cond_wait(&WaitCond, &WaitLock); - pthread_mutex_unlock(&WaitLock); + pthread_mutex_lock(&WaitLock); + if (Idle || threadID >= ActiveThreads) + pthread_cond_wait(&WaitCond, &WaitLock); + + pthread_mutex_unlock(&WaitLock); #else - WaitForSingleObject(SitIdleEvent[threadID], INFINITE); + WaitForSingleObject(SitIdleEvent[threadID], INFINITE); #endif - } + } // If this thread has been assigned work, launch a search - if(Threads[threadID].workIsWaiting) { - Threads[threadID].workIsWaiting = false; - if(Threads[threadID].splitPoint->pvNode) - sp_search_pv(Threads[threadID].splitPoint, threadID); - else - sp_search(Threads[threadID].splitPoint, threadID); - Threads[threadID].idle = true; + if (Threads[threadID].workIsWaiting) + { + assert(!Threads[threadID].idle); + + Threads[threadID].workIsWaiting = false; + if (Threads[threadID].splitPoint->pvNode) + sp_search_pv(Threads[threadID].splitPoint, threadID); + else + sp_search(Threads[threadID].splitPoint, threadID); + + Threads[threadID].idle = true; } // If this thread is the master of a split point and all threads have // finished their work at this split point, return from the idle loop. - if(waitSp != NULL && waitSp->cpus == 0) - return; + if (waitSp != NULL && waitSp->cpus == 0) + return; } Threads[threadID].running = false; @@ -2790,11 +2922,13 @@ namespace { // initializes all split point objects. void init_split_point_stack() { - for(int i = 0; i < THREAD_MAX; i++) - for(int j = 0; j < MaxActiveSplitPoints; j++) { - SplitPointStack[i][j].parent = NULL; - lock_init(&(SplitPointStack[i][j].lock), NULL); - } + + for (int i = 0; i < THREAD_MAX; i++) + for (int j = 0; j < ACTIVE_SPLIT_POINTS_MAX; j++) + { + SplitPointStack[i][j].parent = NULL; + lock_init(&(SplitPointStack[i][j].lock), NULL); + } } @@ -2802,62 +2936,71 @@ namespace { // destroys all locks in the precomputed split point objects. void destroy_split_point_stack() { - for(int i = 0; i < THREAD_MAX; i++) - for(int j = 0; j < MaxActiveSplitPoints; j++) - lock_destroy(&(SplitPointStack[i][j].lock)); + + for (int i = 0; i < THREAD_MAX; i++) + for (int j = 0; j < ACTIVE_SPLIT_POINTS_MAX; j++) + lock_destroy(&(SplitPointStack[i][j].lock)); } // thread_should_stop() checks whether the thread with a given threadID has - // been asked to stop, directly or indirectly. This can happen if a beta - // cutoff has occured in thre thread's currently active split point, or in + // been asked to stop, directly or indirectly. This can happen if a beta + // cutoff has occurred in the thread's currently active split point, or in // some ancestor of the current split point. bool thread_should_stop(int threadID) { + assert(threadID >= 0 && threadID < ActiveThreads); SplitPoint* sp; - if(Threads[threadID].stop) - return true; - if(ActiveThreads <= 2) - return false; - for(sp = Threads[threadID].splitPoint; sp != NULL; sp = sp->parent) - if(sp->finished) { - Threads[threadID].stop = true; + if (Threads[threadID].stop) return true; - } + if (ActiveThreads <= 2) + return false; + for (sp = Threads[threadID].splitPoint; sp != NULL; sp = sp->parent) + if (sp->finished) + { + Threads[threadID].stop = true; + return true; + } return false; } // 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 + // 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 thread_is_available(int slave, int master) { + assert(slave >= 0 && slave < ActiveThreads); assert(master >= 0 && master < ActiveThreads); assert(ActiveThreads > 1); - if(!Threads[slave].idle || slave == master) - return false; + if (!Threads[slave].idle || slave == master) + return false; - if(Threads[slave].activeSplitPoints == 0) - // No active split points means that the thread is available as a slave - // for any other thread. - return true; + // Make a local copy to be sure doesn't change under our feet + int localActiveSplitPoints = Threads[slave].activeSplitPoints; - if(ActiveThreads == 2) - return true; + if (localActiveSplitPoints == 0) + // No active split points means that the thread is available as + // a slave for any other thread. + return true; - // Apply the "helpful master" concept if possible. - if(SplitPointStack[slave][Threads[slave].activeSplitPoints-1].slaves[master]) - return true; + if (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 (SplitPointStack[slave][localActiveSplitPoints - 1].slaves[master]) + return true; return false; } @@ -2867,32 +3010,33 @@ namespace { // a slave for the thread with threadID "master". bool idle_thread_exists(int master) { + assert(master >= 0 && master < ActiveThreads); assert(ActiveThreads > 1); - for(int i = 0; i < ActiveThreads; i++) - if(thread_is_available(i, master)) - return true; + 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 threads at PV nodes. If it does not succeed in splitting the + // several threads at PV nodes. 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 false. If + // split point objects), the function immediately returns false. If // splitting is possible, a SplitPoint object is initialized with all the // data that must be copied to the helper threads (the current position and // search stack, alpha, beta, the search depth, etc.), and we tell our - // helper threads that they have been assigned work. This will cause them - // to instantly leave their idle loops and call sp_search_pv(). When all + // helper threads that they have been assigned work. This will cause them + // to instantly leave their idle loops and call sp_search_pv(). When all // threads have returned from sp_search_pv (or, equivalently, when // splitPoint->cpus becomes 0), split() returns true. bool split(const Position& p, SearchStack* sstck, int ply, Value* alpha, Value* beta, Value* bestValue, const Value futilityValue, - const Value approximateEval, Depth depth, int* moves, - MovePicker* mp, int master, bool pvNode) { + Depth depth, int* moves, MovePicker* mp, int master, bool pvNode) { assert(p.is_ok()); assert(sstck != NULL); @@ -2905,16 +3049,16 @@ namespace { assert(ActiveThreads > 1); SplitPoint* splitPoint; - int i; 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(!idle_thread_exists(master) || - Threads[master].activeSplitPoints >= MaxActiveSplitPoints) { - lock_release(&MPLock); - return false; + if ( !idle_thread_exists(master) + || Threads[master].activeSplitPoints >= ACTIVE_SPLIT_POINTS_MAX) + { + lock_release(&MPLock); + return false; } // Pick the next available split point object from the split point stack @@ -2926,66 +3070,72 @@ namespace { splitPoint->finished = false; splitPoint->ply = ply; splitPoint->depth = depth; - splitPoint->alpha = pvNode? *alpha : (*beta - 1); + splitPoint->alpha = pvNode ? *alpha : (*beta - 1); splitPoint->beta = *beta; splitPoint->pvNode = pvNode; splitPoint->bestValue = *bestValue; splitPoint->futilityValue = futilityValue; - splitPoint->approximateEval = approximateEval; splitPoint->master = master; splitPoint->mp = mp; splitPoint->moves = *moves; splitPoint->cpus = 1; - splitPoint->pos.copy(p); + splitPoint->pos = &p; splitPoint->parentSstack = sstck; - for(i = 0; i < ActiveThreads; i++) - splitPoint->slaves[i] = 0; + for (int i = 0; i < ActiveThreads; i++) + splitPoint->slaves[i] = 0; - // Copy the current position and the search stack to the master thread - memcpy(splitPoint->sstack[master], sstck, (ply+1)*sizeof(SearchStack)); + Threads[master].idle = false; + Threads[master].stop = false; Threads[master].splitPoint = splitPoint; - // Make copies of the current position and search stack for each thread - for(i = 0; i < ActiveThreads && splitPoint->cpus < MaxThreadsPerSplitPoint; - i++) - if(thread_is_available(i, master)) { - memcpy(splitPoint->sstack[i], sstck, (ply+1)*sizeof(SearchStack)); - Threads[i].splitPoint = splitPoint; - splitPoint->slaves[i] = 1; - splitPoint->cpus++; - } + // Allocate available threads setting idle flag to false + for (int i = 0; i < ActiveThreads && splitPoint->cpus < MaxThreadsPerSplitPoint; i++) + if (thread_is_available(i, master)) + { + Threads[i].idle = false; + Threads[i].stop = false; + Threads[i].splitPoint = splitPoint; + splitPoint->slaves[i] = 1; + splitPoint->cpus++; + } - // Tell the threads that they have work to do. This will make them leave - // their idle loop. - for(i = 0; i < ActiveThreads; i++) - if(i == master || splitPoint->slaves[i]) { - Threads[i].workIsWaiting = true; - Threads[i].idle = false; - Threads[i].stop = false; - } + assert(splitPoint->cpus > 1); + // We can release the lock because master and slave threads are already booked lock_release(&MPLock); - // Everything is set up. The master thread enters the idle loop, from + // 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 (int i = 0; i < ActiveThreads; i++) + if (i == master || splitPoint->slaves[i]) + { + memcpy(splitPoint->sstack[i] + ply - 1, sstck + ply - 1, 3 * sizeof(SearchStack)); + Threads[i].workIsWaiting = true; // This makes the slave to exit from idle_loop() + } + + // Everything is set up. The master thread enters the idle loop, from // which it will instantly launch a search, because its workIsWaiting // slot is 'true'. 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 - // (i.e. when // splitPoint->cpus == 0). + // (i.e. when splitPoint->cpus == 0). idle_loop(master, splitPoint); // We have returned from the idle loop, which means that all threads are - // finished. Update alpha, beta and bestvalue, and return. + // finished. Update alpha, beta and bestValue, and return. lock_grab(&MPLock); - if(pvNode) *alpha = splitPoint->alpha; + + if (pvNode) + *alpha = splitPoint->alpha; + *beta = splitPoint->beta; *bestValue = splitPoint->bestValue; Threads[master].stop = false; Threads[master].idle = false; Threads[master].activeSplitPoints--; Threads[master].splitPoint = splitPoint->parent; - lock_release(&MPLock); + lock_release(&MPLock); return true; } @@ -2994,39 +3144,45 @@ namespace { // to start a new search from the root. void wake_sleeping_threads() { - if(ActiveThreads > 1) { - for(int i = 1; i < ActiveThreads; i++) { - Threads[i].idle = true; - Threads[i].workIsWaiting = false; - } + + if (ActiveThreads > 1) + { + for (int i = 1; i < ActiveThreads; i++) + { + Threads[i].idle = true; + Threads[i].workIsWaiting = false; + } + #if !defined(_MSC_VER) pthread_mutex_lock(&WaitLock); pthread_cond_broadcast(&WaitCond); pthread_mutex_unlock(&WaitLock); #else - for(int i = 1; i < THREAD_MAX; i++) - SetEvent(SitIdleEvent[i]); + for (int i = 1; i < THREAD_MAX; i++) + SetEvent(SitIdleEvent[i]); #endif } } // 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. + // 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) { - idle_loop(*(int *)threadID, NULL); + void* init_thread(void *threadID) { + + idle_loop(*(int*)threadID, NULL); return NULL; } #else DWORD WINAPI init_thread(LPVOID threadID) { - idle_loop(*(int *)threadID, NULL); + + idle_loop(*(int*)threadID, NULL); return NULL; }