X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=0f937ed029d1fd749378c64e7326dc4edb4e44cc;hp=53a8bec9b15751981c22354e4a02525274c79887;hb=29fa6f3c5f8a700567a20c0dd2caf18876f736a0;hpb=22ede4442cd285d7365b9497c3be65fb2c66b4be diff --git a/src/search.cpp b/src/search.cpp index 53a8bec9..0f937ed0 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -34,10 +34,10 @@ #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" @@ -129,7 +129,7 @@ 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, Value alpha, Value beta, int pvLine); int64_t nodes; Value pv_score; @@ -145,11 +145,11 @@ namespace { 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 + 1); } + void sort_multipv(int n) { insertion_sort(begin(), begin() + n); } + + int bestMoveChanges; }; @@ -161,13 +161,22 @@ namespace { // operator<<() that will use it to properly format castling moves. enum set960 {}; - std::ostream& operator<< (std::ostream& os, const set960& m) { + std::ostream& operator<< (std::ostream& os, const set960& f) { - os.iword(0) = int(m); + os.iword(0) = int(f); return os; } + // Overload operator << for moves to make it easier to print moves in + // 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); + } + + /// Adjustments // Step 6. Razoring @@ -194,13 +203,13 @@ namespace { // 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]; + Depth CheckExtension[2], PawnPushTo7thExtension[2], PassedPawnExtension[2]; + Depth PawnEndgameExtension[2], MateThreatExtension[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 + // If the TT move is at least SingularExtensionMargin better than the // remaining ones we will extend it. const Value SingularExtensionMargin = Value(0x20); @@ -224,11 +233,6 @@ namespace { template inline Depth reduction(Depth d, int mn) { return (Depth) ReductionMatrix[PV][Min(d / 2, 63)][Min(mn, 63)]; } - // Common adjustments - - // Search depth at iteration 1 - const Depth InitialDepth = ONE_PLY; - // Easy move margin. An easy move candidate must be at least this much // better than the second best move. const Value EasyMoveMargin = Value(0x200); @@ -239,20 +243,13 @@ namespace { // 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; - // Time managment variables + // Time management variables int SearchStartTime, MaxNodes, MaxDepth, ExactMaxTime; bool UseTimeManagement, InfiniteSearch, Pondering, StopOnPonderhit; bool FirstRootMove, StopRequest, QuitRequest, AspirationFailLow; @@ -277,9 +274,8 @@ namespace { /// 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 + template Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth, int ply); template @@ -289,11 +285,11 @@ namespace { inline Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth, int ply) { return depth < ONE_PLY ? qsearch(pos, ss, alpha, beta, DEPTH_ZERO, ply) - : search(pos, ss, alpha, beta, depth, ply); + : search(pos, ss, alpha, beta, depth, ply); } 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 mateThreat, 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); @@ -304,15 +300,15 @@ namespace { bool connected_threat(const Position& pos, Move m, Move threat); Value refine_eval(const TTEntry* tte, Value defaultEval, int ply); void update_history(const Position& pos, Move move, Depth depth, Move movesSearched[], int moveCount); - void update_killers(Move m, SearchStack* ss); + void update_killers(Move m, Move killers[]); void update_gains(const Position& pos, Move move, Value before, Value after); + void qsearch_scoring(Position& pos, MoveStack* mlist, MoveStack* last); int current_search_time(); std::string value_to_uci(Value v); int nps(const Position& pos); 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); @@ -320,7 +316,73 @@ namespace { DWORD WINAPI init_thread(LPVOID threadID); #endif -} + + // MovePickerExt is an extended MovePicker used to choose at compile time + // the proper move source according to the type of node. + template struct MovePickerExt; + + // In Root nodes use RootMoveList Rml as source. Score and sort the root moves + // before to search them. + template<> struct MovePickerExt : public MovePicker { + + MovePickerExt(const Position& p, Move ttm, Depth d, const History& h, SearchStack* ss, Value b) + : MovePicker(p, ttm, d, h, ss, b), firstCall(true) { + Move move; + Value score = VALUE_ZERO; + + // Score root moves using the standard way 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 order pv scores of both moves are equal. + while ((move = MovePicker::get_next_move()) != MOVE_NONE) + for (rm = Rml.begin(); rm != Rml.end(); ++rm) + if (rm->pv[0] == move) + { + rm->non_pv_score = score--; + break; + } + + Rml.sort(); + rm = Rml.begin(); + } + + Move get_next_move() { + + if (!firstCall) + ++rm; + else + firstCall = false; + + return rm != Rml.end() ? rm->pv[0] : MOVE_NONE; + } + + RootMoveList::iterator rm; + bool firstCall; + }; + + // In SpNodes use split point's shared MovePicker object as move 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; + }; + + // Default case, create and use a MovePicker object as 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) {} + + RootMoveList::iterator rm; // Dummy, needed to compile + }; + +} // namespace //// @@ -364,15 +426,15 @@ void init_search() { /// 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) +int64_t perft(Position& pos, Depth depth) { MoveStack mlist[MOVES_MAX]; StateInfo st; Move m; - int sum = 0; + int64_t sum = 0; // Generate all legal moves - MoveStack* last = generate_moves(pos, mlist); + MoveStack* last = generate(pos, mlist); // If we are at the last ply we don't need to do and undo // the moves, just to count them. @@ -394,7 +456,7 @@ int perft(Position& pos, Depth depth) /// 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 +/// search-related 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[], @@ -414,7 +476,7 @@ bool think(Position& pos, bool infinite, bool ponder, int time[], int increment[ // Look for a book move, only during games, not tests if (UseTimeManagement && Options["OwnBook"].value()) { - if (Options["Book File"].value() != OpeningBook.file_name()) + if (Options["Book File"].value() != OpeningBook.name()) OpeningBook.open(Options["Book File"].value()); Move bookMove = OpeningBook.get_move(pos, Options["Best Book Move"].value()); @@ -438,8 +500,6 @@ bool think(Position& pos, bool infinite, bool ponder, int time[], int increment[ 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(); @@ -484,12 +544,13 @@ bool think(Position& pos, bool infinite, bool ponder, int time[], int increment[ std::string name = Options["Search Log Filename"].value(); LogFile.open(name.c_str(), std::ios::out | std::ios::app); - LogFile << "Searching: " << pos.to_fen(Options["UCI_Chess960"].value()) - << "\ninfinite: " << infinite - << " ponder: " << ponder - << " time: " << myTime - << " increment: " << myIncrement - << " moves to go: " << movesToGo << endl; + LogFile << "\nSearching: " << pos.to_fen() + << "\ninfinite: " << infinite + << " ponder: " << ponder + << " time: " << myTime + << " increment: " << myIncrement + << " moves to go: " << movesToGo + << endl; } // We're ready to start thinking. Call the iterative deepening loop function @@ -503,19 +564,14 @@ bool think(Position& pos, bool infinite, bool ponder, int time[], int increment[ if (UseLogFile) { - LogFile << "\nNodes: " << pos.nodes_searched() + LogFile << "Nodes: " << pos.nodes_searched() << "\nNodes/second: " << nps(pos) - << "\nBest move: " << move_to_san(pos, bestMove); + << "\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; - - // Return from think() with unchanged position - pos.undo_move(bestMove); - + LogFile << "\nPonder move: " << move_to_san(pos, ponderMove) << endl; + pos.undo_move(bestMove); // Return from think() with unchanged position LogFile.close(); } @@ -536,123 +592,152 @@ 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, researchCountFL, researchCountFH, aspirationDelta; + Value value, alpha, beta; + Move bestMove, easyMove; // Moves to search are verified, scored and sorted - RootMoveList rml(pos, searchMoves); + Rml.init(pos, searchMoves); - // Handle special case of searching on a mate/stale position - if (rml.size() == 0) + // Initialize FIXME move before Rml.init() + TT.new_search(); + H.clear(); + memset(ss, 0, PLY_MAX_PLUS_2 * sizeof(SearchStack)); + *ponderMove = bestMove = easyMove = MOVE_NONE; + depth = aspirationDelta = 0; + ss->currentMove = MOVE_NULL; // Hack to skip update_gains() + alpha = -VALUE_INFINITE, beta = VALUE_INFINITE; + + // 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(Options["UCI_Chess960"].value()) // 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]; + 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) + while (++depth <= PLY_MAX && (!MaxDepth || depth <= MaxDepth) && !StopRequest) { - // Initialize iteration - Iteration++; - BestMoveChangesByIteration[Iteration] = 0; - - cout << "info depth " << Iteration << endl; + Rml.bestMoveChanges = researchCountFL = researchCountFH = 0; + cout << "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; + // Start with a small aspiration window and, in case of fail high/low, + // research with bigger window until not failing high/low anymore. + while (true) + { + // Search starting from ss+1 to allow calling update_gains() + value = search(pos, ss+1, alpha, beta, depth * ONE_PLY, 0); + + // Send PV line to GUI and write 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); + cout << set960(pos.is_chess960()) + << Rml[i].pv_info_to_uci(pos, depth, alpha, beta, i) << endl; + } - // Search to the current depth, rml is updated and sorted - value = root_search(pos, ss, alpha, beta, depth, rml); + // Value cannot be trusted. Break out immediately! + if (StopRequest) + break; - if (StopRequest) - break; // Value cannot be trusted. Break out immediately! + assert(value >= alpha); - //Save info about search result - ValueByIteration[Iteration] = value; + // In case of failing high/low increase aspiration window and research, + // otherwise exit the fail high/low loop. + if (value >= beta) + { + beta = Min(beta + aspirationDelta * (1 << researchCountFH), VALUE_INFINITE); + researchCountFH++; + } + else if (value <= alpha) + { + AspirationFailLow = true; + StopOnPonderhit = false; + + alpha = Max(alpha - aspirationDelta * (1 << researchCountFL), -VALUE_INFINITE); + researchCountFL++; + } + else + break; + } + + // Collect info about search result + bestMove = Rml[0].pv[0]; + bestValues[depth] = value; + bestMoveChanges[depth] = Rml.bestMoveChanges; + + if (UseLogFile) + LogFile << pretty_pv(pos, depth, value, current_search_time(), Rml[0].pv) << endl; // Drop the easy move if differs from the new best move - if (rml[0].pv[0] != EasyMove) - EasyMove = MOVE_NONE; + if (bestMove != easyMove) + easyMove = MOVE_NONE; - if (UseTimeManagement) + if (UseTimeManagement && !StopRequest) { // 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; + bool noMoreTime = false; // 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 + if ( depth >= 5 + && abs(bestValues[depth]) >= abs(VALUE_MATE) - 100 + && abs(bestValues[depth - 1]) >= abs(VALUE_MATE) - 100) + noMoreTime = true; + + // Stop search early if one move seems to be much better than the + // others or if there is only a single legal move. In this latter + // case we search up to Iteration 8 anyway to get a proper score. + if ( depth >= 7 + && easyMove == bestMove + && ( Rml.size() == 1 + ||( Rml[0].nodes > (pos.nodes_searched() * 85) / 100 && current_search_time() > TimeMgr.available_time() / 16) - ||( rml[0].nodes > (pos.nodes_searched() * 98) / 100 + ||( Rml[0].nodes > (pos.nodes_searched() * 98) / 100 && current_search_time() > TimeMgr.available_time() / 32))) - stopSearch = true; + noMoreTime = 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]); + if (depth > 4 && depth < 50) + TimeMgr.pv_instability(bestMoveChanges[depth], bestMoveChanges[depth-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; + noMoreTime = true; - if (stopSearch) + if (noMoreTime) { if (Pondering) StopOnPonderhit = true; @@ -660,256 +745,10 @@ namespace { 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) - - // 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); - - // 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); - - // 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 nodes " << nodes - << " nps " << nps(pos) - << " time " << current_search_time() << endl; - } - - // 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) - { - // 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); - - // Step 17. Check for new best move - if (value <= alpha && i >= MultiPV) - rml[i].pv_score = -VALUE_INFINITE; - else - { - // PV move or new best move! - - // Update PV - ss->bestMove = move; - rml[i].pv_score = value; - rml[i].extract_pv_from_tt(pos); - - // 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]++; - - // 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); - - for (int j = 0; j < Min(MultiPV, (int)rml.size()); j++) - cout << rml[j].pv_info_to_uci(pos, alpha, beta, j) << endl; - - // 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; - - } // PV move or new best move - - assert(alpha >= oldAlpha); - - AspirationFailLow = (alpha == oldAlpha); - - if (AspirationFailLow && StopOnPonderhit) - StopOnPonderhit = false; - - } // Root moves loop - - // Can we exit fail low loop ? - if (StopRequest || !AspirationFailLow) - break; - - // Prepare for a research after a fail low, each time with a wider window - oldAlpha = alpha = Max(alpha - AspirationDelta * (1 << researchCountFL), -VALUE_INFINITE); - researchCountFL++; - - } // Fail low loop - - // Sort the moves before to return - rml.sort(); - - // Write PV lines 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); - - return alpha; + *ponderMove = Rml[0].pv[1]; + return bestMove; } @@ -920,16 +759,17 @@ 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 + template Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth, int ply) { 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((Root || ply > 0) && ply < PLY_MAX); assert(pos.thread() >= 0 && pos.thread() < ThreadsMgr.active_threads()); Move movesSearched[MOVES_MAX]; + int64_t nodes; StateInfo st; const TTEntry *tte; Key posKey; @@ -938,11 +778,12 @@ namespace { ValueType vt; Value bestValue, value, oldAlpha; Value refinedValue, nullValue, futilityBase, futilityValueScaled; // Non-PV specific - bool isCheck, singleEvasion, singularExtensionNode, moveIsCheck, captureOrPromotion, dangerous; + bool isPvMove, isCheck, singularExtensionNode, moveIsCheck, captureOrPromotion, dangerous; bool mateThreat = false; - int moveCount = 0; + int moveCount = 0, playedMoveCount = 0; int threadID = pos.thread(); SplitPoint* sp = NULL; + refinedValue = bestValue = value = -VALUE_INFINITE; oldAlpha = alpha; isCheck = pos.is_check(); @@ -956,7 +797,8 @@ namespace { 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; @@ -969,10 +811,10 @@ 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 + || ThreadsMgr.cutoff_at_splitpoint(threadID) + || pos.is_draw() + || ply >= PLY_MAX - 1) && !Root) return VALUE_DRAW; // Step 3. Mate distance pruning @@ -982,23 +824,21 @@ namespace { 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 + // and return 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, ply))) { TT.refresh(tte); ss->bestMove = ttMove; // Can be MOVE_NONE @@ -1117,8 +957,8 @@ namespace { } // Step 9. Internal iterative deepening - if ( depth >= IIDDepth[PvNode] - && ttMove == MOVE_NONE + if ( depth >= IIDDepth[PvNode] + && ttMove == MOVE_NONE && (PvNode || (!isCheck && ss->eval >= beta - IIDMargin))) { Depth d = (PvNode ? depth - 2 * ONE_PLY : depth / 2); @@ -1138,14 +978,12 @@ namespace { 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() @@ -1174,18 +1012,42 @@ 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 nodes " << nodes + << " nps " << nps(pos) + << " time " << current_search_time() << endl; + } + + if (current_search_time() >= 1000) + cout << "info currmove " << move + << " currmovenumber " << moveCount << endl; + } + isPvMove = (PvNode && moveCount <= (Root ? 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, mateThreat, &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. + // lower than ttValue minus a margin then we extend ttMove. if ( singularExtensionNode && move == tte->move() && ext < ONE_PLY) @@ -1208,7 +1070,7 @@ split_point_start: // At split points actual search starts from here // Update current move (this must be done after singular extension search) ss->currentMove = move; - newDepth = depth - ONE_PLY + ext; + newDepth = depth - (!Root ? ONE_PLY : DEPTH_ZERO) + ext; // Step 12. Futility pruning (is omitted in PV nodes) if ( !PvNode @@ -1265,10 +1127,19 @@ split_point_start: // At split points actual search starts from here // 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) + 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, ply+1); + } else { // Step 14. Reduced depth search @@ -1283,7 +1154,6 @@ 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; @@ -1304,7 +1174,7 @@ split_point_start: // At split points actual search starts from here // 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) + if (PvNode && value > alpha && (Root || value < beta)) value = -search(pos, ss+1, -beta, -alpha, newDepth, ply+1); } } @@ -1329,7 +1199,7 @@ split_point_start: // At split points actual search starts from here if (SpNode) sp->bestValue = value; - if (value > alpha) + if (!Root && value > alpha) { if (PvNode && value < beta) // We want always alpha < beta { @@ -1351,15 +1221,56 @@ split_point_start: // At split points actual search starts from here } } + 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 + if ( !Root + && !SpNode && depth >= ThreadsMgr.min_split_depth() && ThreadsMgr.active_threads() > 1 && bestValue < beta && ThreadsMgr.available_thread_exists(threadID) && !StopRequest - && !ThreadsMgr.cutoff_at_splitpoint(threadID) - && Iteration <= 99) + && !ThreadsMgr.cutoff_at_splitpoint(threadID)) ThreadsMgr.split(pos, ss, ply, &alpha, beta, &bestValue, depth, threatMove, mateThreat, moveCount, &mp, PvNode); } @@ -1386,8 +1297,8 @@ split_point_start: // At split points actual search starts from here if ( bestValue >= beta && !pos.move_is_capture_or_promotion(move)) { - update_history(pos, move, depth, movesSearched, moveCount); - update_killers(move, ss); + update_history(pos, move, depth, movesSearched, playedMoveCount); + update_killers(move, ss->killers); } } @@ -1589,6 +1500,26 @@ split_point_start: // At split points actual search starts from here } + // qsearch_scoring() scores each move of a list using a qsearch() evaluation, + // it is used in RootMoveList to get an initial scoring. + void qsearch_scoring(Position& pos, MoveStack* mlist, MoveStack* last) { + + SearchStack ss[PLY_MAX_PLUS_2]; + StateInfo st; + + memset(ss, 0, 4 * sizeof(SearchStack)); + ss[0].eval = ss[0].evalMargin = VALUE_NONE; + + for (MoveStack* cur = mlist; cur != last; cur++) + { + ss[0].currentMove = cur->move; + pos.do_move(cur->move, st); + cur->score = -qsearch(pos, ss+1, -VALUE_INFINITE, VALUE_INFINITE, DEPTH_ZERO, 1); + pos.undo_move(cur->move); + } + } + + // check_is_dangerous() tests if a checking move can be pruned in qsearch(). // bestValue is updated only when returning false because in that case move // will be pruned. @@ -1749,22 +1680,19 @@ 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 mateThreat, bool* dangerous) { assert(m != MOVE_NONE); Depth result = DEPTH_ZERO; - *dangerous = moveIsCheck | singleEvasion | mateThreat; + *dangerous = moveIsCheck | mateThreat; if (*dangerous) { if (moveIsCheck && pos.see_sign(m) >= 0) result += CheckExtension[PvNode]; - if (singleEvasion) - result += SingleEvasionExtension[PvNode]; - if (mateThreat) result += MateThreatExtension[PvNode]; } @@ -1809,7 +1737,7 @@ split_point_start: // At split points actual search starts from here // 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) { @@ -1831,7 +1759,7 @@ 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) @@ -1888,8 +1816,9 @@ 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++) { @@ -1897,8 +1826,7 @@ 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); } } @@ -1906,13 +1834,13 @@ split_point_start: // At split points actual search starts from here // 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; + void update_killers(Move m, Move killers[]) { - ss->killers[1] = ss->killers[0]; - ss->killers[0] = m; + if (m != killers[0]) + { + killers[1] = killers[0]; + killers[0] = m; + } } @@ -1926,25 +1854,7 @@ 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)); - } - - - // init_ss_array() does a fast reset of the first entries of a SearchStack - // array and of all the excludedMove and skipNullMove entries. - - void init_ss_array(SearchStack* ss, int size) { - - for (int i = 0; i < size; i++, ss++) - { - ss->excludedMove = MOVE_NONE; - ss->skipNullMove = false; - ss->reduction = DEPTH_ZERO; - ss->sp = NULL; - - if (i < 3) - ss->killers[0] = ss->killers[1] = ss->mateKiller = MOVE_NONE; - } + H.update_gain(pos.piece_on(move_to(m)), move_to(m), -(before + after)); } @@ -1962,7 +1872,7 @@ split_point_start: // At split points actual search starts from here if (abs(v) < VALUE_MATE - PLY_MAX * ONE_PLY) 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) / 2 : -(VALUE_MATE + v) / 2); return s.str(); } @@ -1996,7 +1906,7 @@ 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; @@ -2206,9 +2116,9 @@ split_point_start: // At split points actual search starts from here ss->sp = tsp; if (tsp->pvNode) - search(pos, ss, tsp->alpha, tsp->beta, tsp->depth, tsp->ply); + search(pos, ss, tsp->alpha, tsp->beta, tsp->depth, tsp->ply); else - search(pos, ss, tsp->alpha, tsp->beta, tsp->depth, tsp->ply); + search(pos, ss, tsp->alpha, tsp->beta, tsp->depth, tsp->ply); assert(threads[threadID].state == THREAD_SEARCHING); @@ -2596,7 +2506,7 @@ split_point_start: // At split points actual search starts from here 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)); @@ -2610,10 +2520,10 @@ 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. + // formatted according to UCI specification. 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::string RootMove::pv_info_to_uci(Position& pos, int depth, Value alpha, Value beta, int pvLine) { std::stringstream s, l; Move* m = pv; @@ -2621,7 +2531,7 @@ split_point_start: // At split points actual search starts from here while (*m != MOVE_NONE) l << *m++ << " "; - s << "info depth " << Iteration // FIXME + s << "info depth " << depth << " seldepth " << int(m - pv) << " multipv " << pvLine + 1 << " score " << value_to_uci(pv_score) @@ -2631,30 +2541,21 @@ split_point_start: // At split points actual search starts from here << " nps " << nps(pos) << " pv " << l.str(); - if (UseLogFile && pvLine == 0) - { - ValueType t = pv_score >= beta ? VALUE_TYPE_LOWER : - pv_score <= alpha ? VALUE_TYPE_UPPER : VALUE_TYPE_EXACT; - - LogFile << pretty_pv(pos, current_search_time(), Iteration, pv_score, t, pv) << endl; - } return s.str(); } - RootMoveList::RootMoveList(Position& pos, Move searchMoves[]) { + void RootMoveList::init(Position& pos, Move searchMoves[]) { - SearchStack ss[PLY_MAX_PLUS_2]; MoveStack mlist[MOVES_MAX]; - StateInfo st; Move* sm; - // Initialize search stack - init_ss_array(ss, PLY_MAX_PLUS_2); - ss[0].eval = ss[0].evalMargin = VALUE_NONE; + clear(); + bestMoveChanges = 0; - // Generate all legal moves - MoveStack* last = generate_moves(pos, mlist); + // Generate all legal moves and score them + MoveStack* last = generate(pos, mlist); + qsearch_scoring(pos, mlist, last); // Add each move to the RootMoveList's vector for (MoveStack* cur = mlist; cur != last; cur++) @@ -2666,38 +2567,13 @@ split_point_start: // At split points actual search starts from here 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); - RootMove rm; - rm.pv[0] = ss[0].currentMove = cur->move; + rm.pv[0] = cur->move; rm.pv[1] = MOVE_NONE; - rm.pv_score = -qsearch(pos, ss+1, -VALUE_INFINITE, VALUE_INFINITE, DEPTH_ZERO, 1); + rm.pv_score = Value(cur->score); push_back(rm); - - pos.undo_move(cur->move); } sort(); } - // 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. - - void RootMoveList::set_non_pv_scores(const Position& pos) - { - Move move; - Value score = VALUE_ZERO; - MovePicker mp(pos, MOVE_NONE, ONE_PLY, H); - - 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; - } - } - } // namespace