X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=eb9f63f15bca317f4fa148bf304472f7eb204edf;hp=037c44ddfe37a483a373c34c8b9eed1f3246c4e5;hb=04ac1bcabefaa5b6895b8c20c3c6e3ba7e3a5a61;hpb=bb3427ca85bdb20b4c8af12b63f635d03c5e9146 diff --git a/src/search.cpp b/src/search.cpp index 037c44dd..eb9f63f1 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -1,7 +1,7 @@ /* Stockfish, a UCI chess playing engine derived from Glaurung 2.1 Copyright (C) 2004-2008 Tord Romstad (Glaurung author) - Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2008-2012 Marco Costalba, Joona Kiiski, Tord Romstad Stockfish is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -17,20 +17,18 @@ along with this program. If not, see . */ +#include #include #include #include #include #include #include -#include -#include #include "book.h" #include "evaluate.h" #include "history.h" #include "misc.h" -#include "move.h" #include "movegen.h" #include "movepick.h" #include "search.h" @@ -39,20 +37,19 @@ #include "tt.h" #include "ucioption.h" -using std::cout; -using std::endl; -using std::string; -using Search::Signals; -using Search::Limits; - namespace Search { volatile SignalsType Signals; LimitsType Limits; - std::vector RootMoves; + std::vector RootMoves; Position RootPosition; } +using std::string; +using std::cout; +using std::endl; +using namespace Search; + namespace { // Set to true to force running with one thread. Used for debugging @@ -61,44 +58,10 @@ namespace { // Different node types, used as template parameter enum NodeType { Root, PV, NonPV, SplitPointRoot, SplitPointPV, SplitPointNonPV }; - // RootMove struct is used for moves at the root of the tree. For each root - // move, we store a score, a node count, and a PV (really a refutation - // in the case of moves which fail low). Score is normally set at - // -VALUE_INFINITE for all non-pv moves. - struct RootMove { - - // RootMove::operator<() is the comparison function used when - // sorting the moves. A move m1 is considered to be better - // than a move m2 if it has an higher score - bool operator<(const RootMove& m) const { return score < m.score; } - - void extract_pv_from_tt(Position& pos); - void insert_pv_in_tt(Position& pos); - - int64_t nodes; - Value score; - Value prevScore; - std::vector pv; - }; - - // RootMoveList struct is mainly a std::vector of RootMove objects - struct RootMoveList : public std::vector { - - void init(Position& pos, Move rootMoves[]); - RootMove* find(const Move& m, int startIndex = 0); - - int bestMoveChanges; - }; - - - /// Constants - // Lookup table to check if a Piece is a slider and its access function const bool Slidings[18] = { 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 1 }; inline bool piece_is_slider(Piece p) { return Slidings[p]; } - // Step 6. Razoring - // Maximum depth for razoring const Depth RazorDepth = 4 * ONE_PLY; @@ -108,8 +71,6 @@ namespace { // Maximum depth for use of dynamic threat detection when null move fails low const Depth ThreatDepth = 5 * ONE_PLY; - // Step 9. Internal iterative deepening - // Minimum depth for use of internal iterative deepening const Depth IIDDepth[] = { 8 * ONE_PLY, 5 * ONE_PLY }; @@ -117,19 +78,9 @@ namespace { // when the static evaluation is bigger then beta - IIDMargin. const Value IIDMargin = Value(0x100); - // Step 11. Decide the new search depth - - // Extensions. Array index 0 is used for non-PV nodes, index 1 for PV nodes - const Depth CheckExtension[] = { ONE_PLY / 2, ONE_PLY / 1 }; - const Depth PawnEndgameExtension[] = { ONE_PLY / 1, ONE_PLY / 1 }; - const Depth PawnPushTo7thExtension[] = { ONE_PLY / 2, ONE_PLY / 2 }; - const Depth PassedPawnExtension[] = { DEPTH_ZERO, ONE_PLY / 2 }; - // Minimum depth for use of singular extension const Depth SingularExtensionDepth[] = { 8 * ONE_PLY, 6 * ONE_PLY }; - // Step 12. Futility pruning - // Futility margin for quiescence search const Value FutilityMarginQS = Value(0x80); @@ -148,8 +99,6 @@ namespace { return d < 16 * ONE_PLY ? FutilityMoveCounts[d] : MAX_MOVES; } - // Step 14. Reduced search - // Reduction lookup tables (initialized at startup) and their access function int8_t Reductions[2][64][64]; // [pv][depth][moveNumber] @@ -158,40 +107,29 @@ namespace { return (Depth) Reductions[PvNode][std::min(int(d) / ONE_PLY, 63)][std::min(mn, 63)]; } - // Easy move margin. An easy move candidate must be at least this much - // better than the second best move. + // Easy move margin. An easy move candidate must be at least this much better + // than the second best move. const Value EasyMoveMargin = Value(0x150); + // This is the minimum interval in msec between two check_time() calls + const int TimerResolution = 5; - /// Namespace variables - - // Root move list - RootMoveList Rml; - // MultiPV mode - int MultiPV, UCIMultiPV, MultiPVIdx; - - // Time management variables + size_t MultiPV, UCIMultiPV, PVIdx; TimeManager TimeMgr; - - // Skill level adjustment + int BestMoveChanges; int SkillLevel; - bool SkillLevelEnabled; - - // History table + bool SkillLevelEnabled, Chess960; History H; - /// Local functions - - Move id_loop(Position& pos, Move rootMoves[], Move* ponderMove); - template - Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth); + Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth); template - Value qsearch(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth); + Value qsearch(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth); + void id_loop(Position& pos); bool check_is_dangerous(Position &pos, Move move, Value futilityBase, Value beta, Value *bValue); bool connected_moves(const Position& pos, Move m1, Move m2); Value value_to_tt(Value v, int ply); @@ -199,106 +137,59 @@ namespace { bool can_return_tt(const TTEntry* tte, Depth depth, Value beta, int ply); bool connected_threat(const Position& pos, Move m, Move threat); Value refine_eval(const TTEntry* tte, Value defaultEval, int ply); - void update_history(const Position& pos, Move move, Depth depth, Move movesSearched[], int moveCount); - void do_skill_level(Move* best, Move* ponder); - - int elapsed_search_time(int set = 0); + Move do_skill_level(); + int elapsed_time(bool reset = false); string score_to_uci(Value v, Value alpha = -VALUE_INFINITE, Value beta = VALUE_INFINITE); - string speed_to_uci(int64_t nodes); - string pv_to_uci(const Move pv[], int pvNum, bool chess960); - string pretty_pv(Position& pos, int depth, Value score, int time, Move pv[]); - string depth_to_uci(Depth depth); - - // MovePickerExt template class extends MovePicker and allows to choose at compile - // time the proper moves source according to the type of node. In the default case - // we simply create and use a standard MovePicker object. + void pv_info_to_log(Position& pos, int depth, Value score, int time, Move pv[]); + void pv_info_to_uci(const Position& pos, int depth, Value alpha, Value beta); + + // MovePickerExt class template extends MovePicker and allows to choose at + // compile time the proper moves source according to the type of node. In the + // default case we simply create and use a standard MovePicker object. template struct MovePickerExt : public MovePicker { - MovePickerExt(const Position& p, Move ttm, Depth d, const History& h, SearchStack* ss, Value b) + MovePickerExt(const Position& p, Move ttm, Depth d, const History& h, Stack* ss, Value b) : MovePicker(p, ttm, d, h, ss, b) {} }; // In case of a SpNode we use split point's shared MovePicker object as moves source template<> struct MovePickerExt : public MovePicker { - MovePickerExt(const Position& p, Move ttm, Depth d, const History& h, SearchStack* ss, Value b) + MovePickerExt(const Position& p, Move ttm, Depth d, const History& h, Stack* ss, Value b) : MovePicker(p, ttm, d, h, ss, b), mp(ss->sp->mp) {} - Move get_next_move() { return mp->get_next_move(); } + Move next_move() { return mp->next_move(); } MovePicker* mp; }; - // Overload operator<<() to make it easier to print moves in a coordinate - // notation compatible with UCI protocol. - std::ostream& operator<<(std::ostream& os, Move m) { - - bool chess960 = (os.iword(0) != 0); // See set960() - return os << move_to_uci(m, chess960); - } - - // When formatting a move for std::cout we must know if we are in Chess960 - // or not. To keep using the handy operator<<() on the move the trick is to - // embed this flag in the stream itself. Function-like named enum set960 is - // used as a custom manipulator and the stream internal general-purpose array, - // accessed through ios_base::iword(), is used to pass the flag to the move's - // operator<<() that will read it to properly format castling moves. - enum set960 {}; - - std::ostream& operator<< (std::ostream& os, const set960& f) { - - os.iword(0) = int(f); - return os; - } - - // extension() decides whether a move should be searched with normal depth, - // or with extended depth. Certain classes of moves (checking moves, in - // particular) are searched with bigger depth than ordinary moves and in - // any case are marked as 'dangerous'. Note that also if a move is not - // extended, as example because the corresponding UCI option is set to zero, - // the move is marked as 'dangerous' so, at least, we avoid to prune it. - template - FORCE_INLINE Depth extension(const Position& pos, Move m, bool captureOrPromotion, - bool moveIsCheck, bool* dangerous) { - assert(m != MOVE_NONE); - - Depth result = DEPTH_ZERO; - *dangerous = moveIsCheck; - - if (moveIsCheck && pos.see_sign(m) >= 0) - result += CheckExtension[PvNode]; + // is_dangerous() checks whether a move belongs to some classes of known + // 'dangerous' moves so that we avoid to prune it. + FORCE_INLINE bool is_dangerous(const Position& pos, Move m, bool captureOrPromotion) { - if (type_of(pos.piece_on(move_from(m))) == PAWN) + // Test for a pawn pushed to 7th or a passed pawn move + if (type_of(pos.piece_moved(m)) == PAWN) { Color c = pos.side_to_move(); - if (relative_rank(c, move_to(m)) == RANK_7) - { - result += PawnPushTo7thExtension[PvNode]; - *dangerous = true; - } - if (pos.pawn_is_passed(c, move_to(m))) - { - result += PassedPawnExtension[PvNode]; - *dangerous = true; - } + if ( relative_rank(c, to_sq(m)) == RANK_7 + || pos.pawn_is_passed(c, to_sq(m))) + return true; } + // Test for a capture that triggers a pawn endgame if ( captureOrPromotion - && type_of(pos.piece_on(move_to(m))) != PAWN + && type_of(pos.piece_on(to_sq(m))) != PAWN && ( pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK) - - PieceValueMidgame[pos.piece_on(move_to(m))] == VALUE_ZERO) + - PieceValueMidgame[pos.piece_on(to_sq(m))] == VALUE_ZERO) && !is_special(m)) - { - result += PawnEndgameExtension[PvNode]; - *dangerous = true; - } + return true; - return std::min(result, ONE_PLY); + return false; } } // namespace -/// init_search() is called during startup to initialize various lookup tables +/// Search::init() is called during startup to initialize various lookup tables void Search::init() { @@ -325,65 +216,63 @@ void Search::init() { } -/// perft() is our utility to verify move generation. All the leaf nodes up to -/// the given depth are generated and counted and the sum returned. +/// Search::perft() is our utility to verify move generation. All the leaf nodes +/// up to the given depth are generated and counted and the sum returned. int64_t Search::perft(Position& pos, Depth depth) { StateInfo st; - int64_t sum = 0; + int64_t cnt = 0; - // Generate all legal moves MoveList ml(pos); - // If we are at the last ply we don't need to do and undo - // the moves, just to count them. - if (depth <= ONE_PLY) + // At the last ply just return the number of moves (leaf nodes) + if (depth == ONE_PLY) return ml.size(); - // Loop through all legal moves CheckInfo ci(pos); for ( ; !ml.end(); ++ml) { pos.do_move(ml.move(), st, ci, pos.move_gives_check(ml.move(), ci)); - sum += perft(pos, depth - ONE_PLY); + cnt += perft(pos, depth - ONE_PLY); pos.undo_move(ml.move()); } - return sum; + return cnt; } -/// think() is the external interface to Stockfish's search, and is called when -/// the program receives the UCI 'go' command. It initializes various global -/// variables, and calls id_loop(). It returns false when a "quit" command is -/// received during the search. +/// Search::think() is the external interface to Stockfish's search, and is +/// called by the main thread when the program receives the UCI 'go' command. It +/// searches from RootPosition and at the end prints the "bestmove" to output. void Search::think() { static Book book; // Defined static to initialize the PRNG only once Position& pos = RootPosition; + Chess960 = pos.is_chess960(); + elapsed_time(true); + TimeMgr.init(Limits, pos.startpos_ply_counter()); + TT.new_search(); + H.clear(); - // Save "search start" time and reset elapsed time to zero - elapsed_search_time(get_system_time()); + if (RootMoves.empty()) + { + cout << "info depth 0 score " + << score_to_uci(pos.in_check() ? -VALUE_MATE : VALUE_DRAW) << endl; - // Set output stream mode: normal or chess960. Castling notation is different - cout << set960(pos.is_chess960()); + RootMoves.push_back(MOVE_NONE); + goto finalize; + } - // Look for a book move - if (Options["OwnBook"].value()) + if (Options["OwnBook"]) { - if (Options["Book File"].value() != book.name()) - book.open(Options["Book File"].value()); + Move bookMove = book.probe(pos, Options["Book File"], Options["Best Book Move"]); - Move bookMove = book.probe(pos, Options["Best Book Move"].value()); - if (bookMove != MOVE_NONE) + if (bookMove && count(RootMoves.begin(), RootMoves.end(), bookMove)) { - if (!Signals.stop && (Limits.ponder || Limits.infinite)) - Threads.wait_for_stop_or_ponderhit(); - - cout << "bestmove " << bookMove << endl; - return; + std::swap(RootMoves[0], *find(RootMoves.begin(), RootMoves.end(), bookMove)); + goto finalize; } } @@ -391,27 +280,24 @@ void Search::think() { read_evaluation_uci_options(pos.side_to_move()); Threads.read_uci_options(); - // Set a new TT size if changed - TT.set_size(Options["Hash"].value()); - - if (Options["Clear Hash"].value()) + TT.set_size(Options["Hash"]); + if (Options["Clear Hash"]) { - Options["Clear Hash"].set_value("false"); + Options["Clear Hash"] = false; TT.clear(); } - UCIMultiPV = Options["MultiPV"].value(); - SkillLevel = Options["Skill Level"].value(); + UCIMultiPV = Options["MultiPV"]; + SkillLevel = Options["Skill Level"]; // Do we have to play with skill handicap? In this case enable MultiPV that // we will use behind the scenes to retrieve a set of possible moves. SkillLevelEnabled = (SkillLevel < 20); - MultiPV = (SkillLevelEnabled ? std::max(UCIMultiPV, 4) : UCIMultiPV); + MultiPV = (SkillLevelEnabled ? std::max(UCIMultiPV, (size_t)4) : UCIMultiPV); - // Write current search header to log file - if (Options["Use Search Log"].value()) + if (Options["Use Search Log"]) { - Log log(Options["Search Log Filename"].value()); + Log log(Options["Search Log Filename"]); log << "\nSearching: " << pos.to_fen() << "\ninfinite: " << Limits.infinite << " ponder: " << Limits.ponder @@ -421,7 +307,6 @@ void Search::think() { << endl; } - // Wake up needed threads and reset maxPly counter for (int i = 0; i < Threads.size(); i++) { Threads[i].maxPly = 0; @@ -430,54 +315,44 @@ void Search::think() { // Set best timer interval to avoid lagging under time pressure. Timer is // used to check for remaining available thinking time. - TimeMgr.init(Limits, pos.startpos_ply_counter()); - - if (TimeMgr.available_time()) - Threads.set_timer(std::min(100, std::max(TimeMgr.available_time() / 8, 20))); + if (Limits.use_time_management()) + Threads.set_timer(std::min(100, std::max(TimeMgr.available_time() / 16, TimerResolution))); else Threads.set_timer(100); - // We're ready to start thinking. Call the iterative deepening loop function - Move ponderMove = MOVE_NONE; - Move bestMove = id_loop(pos, &RootMoves[0], &ponderMove); + // We're ready to start searching. Call the iterative deepening loop function + id_loop(pos); - // Stop timer, no need to check for available time any more + // Stop timer and send all the slaves to sleep, if not already sleeping Threads.set_timer(0); - - // This makes all the slave threads to go to sleep, if not already sleeping Threads.set_size(1); - // Write current search final statistics to log file - if (Options["Use Search Log"].value()) + if (Options["Use Search Log"]) { - int e = elapsed_search_time(); + int e = elapsed_time(); - Log log(Options["Search Log Filename"].value()); + Log log(Options["Search Log Filename"]); log << "Nodes: " << pos.nodes_searched() << "\nNodes/second: " << (e > 0 ? pos.nodes_searched() * 1000 / e : 0) - << "\nBest move: " << move_to_san(pos, bestMove); + << "\nBest move: " << move_to_san(pos, RootMoves[0].pv[0]); StateInfo st; - pos.do_move(bestMove, st); - log << "\nPonder move: " << move_to_san(pos, ponderMove) << endl; - pos.undo_move(bestMove); // Return from think() with unchanged position + pos.do_move(RootMoves[0].pv[0], st); + log << "\nPonder move: " << move_to_san(pos, RootMoves[0].pv[1]) << endl; + pos.undo_move(RootMoves[0].pv[0]); } - // When we reach max depth we arrive here even without a StopRequest, but if - // we are pondering or in infinite search, we shouldn't print the best move - // before we are told to do so. +finalize: + + // When we reach max depth we arrive here even without Signals.stop is raised, + // but if we are pondering or in infinite search, we shouldn't print the best + // move before we are told to do so. if (!Signals.stop && (Limits.ponder || Limits.infinite)) Threads.wait_for_stop_or_ponderhit(); - // Could be MOVE_NONE when searching on a stalemate position - cout << "bestmove " << bestMove; - - // UCI protol is not clear on allowing sending an empty ponder move, instead - // it is clear that ponder move is optional. So skip it if empty. - if (ponderMove != MOVE_NONE) - cout << " ponder " << ponderMove; - - cout << endl; + // Best move could be MOVE_NONE when searching on a stalemate position + cout << "bestmove " << move_to_uci(RootMoves[0].pv[0], Chess960) + << " ponder " << move_to_uci(RootMoves[0].pv[1], Chess960) << endl; } @@ -487,60 +362,39 @@ namespace { // with increasing depth until the allocated thinking time has been consumed, // user stops the search, or the maximum search depth is reached. - Move id_loop(Position& pos, Move rootMoves[], Move* ponderMove) { + void id_loop(Position& pos) { - SearchStack ss[PLY_MAX_PLUS_2]; - Value bestValues[PLY_MAX_PLUS_2]; - int bestMoveChanges[PLY_MAX_PLUS_2]; - int depth, aspirationDelta; - Value bestValue, alpha, beta; - Move bestMove, skillBest, skillPonder; + Stack ss[MAX_PLY_PLUS_2]; + int depth, prevBestMoveChanges; + Value bestValue, alpha, beta, delta; bool bestMoveNeverChanged = true; + Move skillBest = MOVE_NONE; - // Initialize stuff before a new search - memset(ss, 0, 4 * sizeof(SearchStack)); - TT.new_search(); - H.clear(); - *ponderMove = bestMove = skillBest = skillPonder = MOVE_NONE; - depth = aspirationDelta = 0; - bestValue = alpha = -VALUE_INFINITE, beta = VALUE_INFINITE; + memset(ss, 0, 4 * sizeof(Stack)); + depth = BestMoveChanges = 0; + bestValue = delta = -VALUE_INFINITE; ss->currentMove = MOVE_NULL; // Hack to skip update gains - // Moves to search are verified and copied - Rml.init(pos, rootMoves); - - // Handle special case of searching on a mate/stalemate position - if (!Rml.size()) - { - cout << "info" << depth_to_uci(DEPTH_ZERO) - << score_to_uci(pos.in_check() ? -VALUE_MATE : VALUE_DRAW, alpha, beta) << endl; - - return MOVE_NONE; - } - // Iterative deepening loop until requested to stop or target depth reached - while (!Signals.stop && ++depth <= PLY_MAX && (!Limits.maxDepth || depth <= Limits.maxDepth)) + while (!Signals.stop && ++depth <= MAX_PLY && (!Limits.maxDepth || depth <= Limits.maxDepth)) { - // Save now last iteration's scores, before Rml moves are reordered - for (size_t i = 0; i < Rml.size(); i++) - Rml[i].prevScore = Rml[i].score; + // Save last iteration's scores before first PV line is searched and all + // the move scores but the (new) PV are set to -VALUE_INFINITE. + for (size_t i = 0; i < RootMoves.size(); i++) + RootMoves[i].prevScore = RootMoves[i].score; - Rml.bestMoveChanges = 0; + prevBestMoveChanges = BestMoveChanges; + BestMoveChanges = 0; // MultiPV loop. We perform a full root search for each PV line - for (MultiPVIdx = 0; MultiPVIdx < std::min(MultiPV, (int)Rml.size()); MultiPVIdx++) + for (PVIdx = 0; PVIdx < std::min(MultiPV, RootMoves.size()); PVIdx++) { - // Calculate dynamic aspiration window based on previous iterations - if (depth >= 5 && abs(Rml[MultiPVIdx].prevScore) < VALUE_KNOWN_WIN) + // Set aspiration window default width + if (depth >= 5 && abs(RootMoves[PVIdx].prevScore) < VALUE_KNOWN_WIN) { - int prevDelta1 = bestValues[depth - 1] - bestValues[depth - 2]; - int prevDelta2 = bestValues[depth - 2] - bestValues[depth - 3]; - - aspirationDelta = std::min(std::max(abs(prevDelta1) + abs(prevDelta2) / 2, 16), 24); - aspirationDelta = (aspirationDelta + 7) / 8 * 8; // Round to match grainSize - - alpha = std::max(Rml[MultiPVIdx].prevScore - aspirationDelta, -VALUE_INFINITE); - beta = std::min(Rml[MultiPVIdx].prevScore + aspirationDelta, VALUE_INFINITE); + delta = Value(16); + alpha = RootMoves[PVIdx].prevScore - delta; + beta = RootMoves[PVIdx].prevScore + delta; } else { @@ -561,114 +415,90 @@ namespace { // we want to keep the same order for all the moves but the new // PV that goes to the front. Note that in case of MultiPV search // the already searched PV lines are preserved. - sort(Rml.begin() + MultiPVIdx, Rml.end()); + sort(RootMoves.begin() + PVIdx, RootMoves.end()); // In case we have found an exact score and we are going to leave // the fail high/low loop then reorder the PV moves, otherwise // leave the last PV move in its position so to be searched again. // Of course this is needed only in MultiPV search. - if (MultiPVIdx && bestValue > alpha && bestValue < beta) - sort(Rml.begin(), Rml.begin() + MultiPVIdx); + if (PVIdx && bestValue > alpha && bestValue < beta) + sort(RootMoves.begin(), RootMoves.begin() + PVIdx); - // Write PV back to transposition table in case the relevant entries - // have been overwritten during the search. - for (int i = 0; i <= MultiPVIdx; i++) - Rml[i].insert_pv_in_tt(pos); + // Write PV back to transposition table in case the relevant + // entries have been overwritten during the search. + for (size_t i = 0; i <= PVIdx; i++) + RootMoves[i].insert_pv_in_tt(pos); - // If search has been stopped exit the aspiration window loop, - // note that sorting and writing PV back to TT is safe becuase - // Rml is still valid, although refers to the previous iteration. + // If search has been stopped exit the aspiration window loop. + // Sorting and writing PV back to TT is safe becuase RootMoves + // is still valid, although refers to previous iteration. if (Signals.stop) break; // Send full PV info to GUI if we are going to leave the loop or - // if we have a fail high/low and we are deep in the search. UCI - // protocol requires to send all the PV lines also if are still - // to be searched and so refer to the previous search's score. - if ((bestValue > alpha && bestValue < beta) || elapsed_search_time() > 2000) - for (int i = 0; i < std::min(UCIMultiPV, (int)Rml.size()); i++) - { - bool updated = (i <= MultiPVIdx); - - if (depth == 1 && !updated) - continue; - - Depth d = (updated ? depth : depth - 1) * ONE_PLY; - Value s = (updated ? Rml[i].score : Rml[i].prevScore); - - cout << "info" - << depth_to_uci(d) - << (i == MultiPVIdx ? score_to_uci(s, alpha, beta) : score_to_uci(s)) - << speed_to_uci(pos.nodes_searched()) - << pv_to_uci(&Rml[i].pv[0], i + 1, pos.is_chess960()) - << endl; - } + // if we have a fail high/low and we are deep in the search. + if ((bestValue > alpha && bestValue < beta) || elapsed_time() > 2000) + pv_info_to_uci(pos, depth, alpha, beta); // In case of failing high/low increase aspiration window and // research, otherwise exit the fail high/low loop. if (bestValue >= beta) { - beta = std::min(beta + aspirationDelta, VALUE_INFINITE); - aspirationDelta += aspirationDelta / 2; + beta += delta; + delta += delta / 2; } else if (bestValue <= alpha) { Signals.failedLowAtRoot = true; Signals.stopOnPonderhit = false; - alpha = std::max(alpha - aspirationDelta, -VALUE_INFINITE); - aspirationDelta += aspirationDelta / 2; + alpha -= delta; + delta += delta / 2; } else break; + assert(alpha >= -VALUE_INFINITE && beta <= VALUE_INFINITE); + } while (abs(bestValue) < VALUE_KNOWN_WIN); } - // Collect info about search result - bestMove = Rml[0].pv[0]; - *ponderMove = Rml[0].pv[1]; - bestValues[depth] = bestValue; - bestMoveChanges[depth] = Rml.bestMoveChanges; - - // Skills: Do we need to pick now the best and the ponder moves ? + // Skills: Do we need to pick now the best move ? if (SkillLevelEnabled && depth == 1 + SkillLevel) - do_skill_level(&skillBest, &skillPonder); + skillBest = do_skill_level(); - if (Options["Use Search Log"].value()) - { - Log log(Options["Search Log Filename"].value()); - log << pretty_pv(pos, depth, bestValue, elapsed_search_time(), &Rml[0].pv[0]) << endl; - } + if (Options["Use Search Log"]) + pv_info_to_log(pos, depth, bestValue, elapsed_time(), &RootMoves[0].pv[0]); // Filter out startup noise when monitoring best move stability - if (depth > 2 && bestMoveChanges[depth]) + if (depth > 2 && BestMoveChanges) bestMoveNeverChanged = false; // Do we have time for the next iteration? Can we stop searching now? - if (!Signals.stop && !Signals.stopOnPonderhit && Limits.useTimeManagement()) + if (!Signals.stop && !Signals.stopOnPonderhit && Limits.use_time_management()) { - bool stop = false; // Local variable instead of the volatile Signals.stop + bool stop = false; // Local variable, not the volatile Signals.stop // Take in account some extra time if the best move has changed if (depth > 4 && depth < 50) - TimeMgr.pv_instability(bestMoveChanges[depth], bestMoveChanges[depth - 1]); + TimeMgr.pv_instability(BestMoveChanges, prevBestMoveChanges); - // Stop search if most of available time is already consumed. We probably don't - // have enough time to search the first move at the next iteration anyway. - if (elapsed_search_time() > (TimeMgr.available_time() * 62) / 100) + // Stop search if most of available time is already consumed. We + // probably don't have enough time to search the first move at the + // next iteration anyway. + if (elapsed_time() > (TimeMgr.available_time() * 62) / 100) stop = true; // Stop search early if one move seems to be much better than others - if ( depth >= 10 + if ( depth >= 12 && !stop - && ( bestMoveNeverChanged - || elapsed_search_time() > (TimeMgr.available_time() * 40) / 100)) + && ( (bestMoveNeverChanged && pos.captured_piece_type()) + || elapsed_time() > (TimeMgr.available_time() * 40) / 100)) { Value rBeta = bestValue - EasyMoveMargin; - (ss+1)->excludedMove = bestMove; + (ss+1)->excludedMove = RootMoves[0].pv[0]; (ss+1)->skipNullMove = true; - Value v = search(pos, ss+1, rBeta - 1, rBeta, (depth * ONE_PLY) / 2); + Value v = search(pos, ss+1, rBeta - 1, rBeta, (depth - 3) * ONE_PLY); (ss+1)->skipNullMove = false; (ss+1)->excludedMove = MOVE_NONE; @@ -680,7 +510,7 @@ namespace { { // If we are allowed to ponder do not stop the search now but // keep pondering until GUI sends "ponderhit" or "stop". - if (Limits.ponder) // FIXME racing + if (Limits.ponder) Signals.stopOnPonderhit = true; else Signals.stop = true; @@ -688,17 +518,14 @@ namespace { } } - // When using skills overwrite best and ponder moves with the sub-optimal ones + // When using skills swap best PV line with the sub-optimal one if (SkillLevelEnabled) { if (skillBest == MOVE_NONE) // Still unassigned ? - do_skill_level(&skillBest, &skillPonder); + skillBest = do_skill_level(); - bestMove = skillBest; - *ponderMove = skillPonder; + std::swap(RootMoves[0], *find(RootMoves.begin(), RootMoves.end(), skillBest)); } - - return bestMove; } @@ -710,19 +537,18 @@ namespace { // here: This is taken care of after we return from the split point. template - Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth) { + Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth) { const bool PvNode = (NT == PV || NT == Root || NT == SplitPointPV || NT == SplitPointRoot); const bool SpNode = (NT == SplitPointPV || NT == SplitPointNonPV || NT == SplitPointRoot); const bool RootNode = (NT == Root || NT == SplitPointRoot); - assert(alpha >= -VALUE_INFINITE && alpha <= VALUE_INFINITE); - assert(beta > alpha && beta <= VALUE_INFINITE); - assert(PvNode || alpha == beta - 1); + assert(alpha >= -VALUE_INFINITE && alpha < beta && beta <= VALUE_INFINITE); + assert((alpha == beta - 1) || PvNode); + assert(depth > DEPTH_ZERO); assert(pos.thread() >= 0 && pos.thread() < Threads.size()); Move movesSearched[MAX_MOVES]; - int64_t nodes; StateInfo st; const TTEntry *tte; Key posKey; @@ -763,16 +589,25 @@ namespace { } // Step 2. Check for aborted search and immediate draw + // Enforce node limit here. FIXME: This only works with 1 search thread. + if (Limits.maxNodes && pos.nodes_searched() >= Limits.maxNodes) + Signals.stop = true; + if (( Signals.stop || pos.is_draw() - || ss->ply > PLY_MAX) && !RootNode) + || ss->ply > MAX_PLY) && !RootNode) return VALUE_DRAW; - // Step 3. Mate distance pruning + // Step 3. Mate distance pruning. Even if we mate at the next move our score + // would be at best mate_in(ss->ply+1), but if alpha is already bigger because + // a shorter mate was found upward in the tree then there is no need to search + // further, we will never beat current alpha. Same logic but with reversed signs + // applies also in the opposite condition of being mated instead of giving mate, + // in this case return a fail-high score. if (!RootNode) { - alpha = std::max(value_mated_in(ss->ply), alpha); - beta = std::min(value_mate_in(ss->ply+1), beta); + alpha = std::max(mated_in(ss->ply), alpha); + beta = std::min(mate_in(ss->ply+1), beta); if (alpha >= beta) return alpha; } @@ -781,9 +616,9 @@ namespace { // We don't want the score of a partial search to overwrite a previous full search // TT value, so we use a different position key in case of an excluded move. excludedMove = ss->excludedMove; - posKey = excludedMove ? pos.get_exclusion_key() : pos.get_key(); + posKey = excludedMove ? pos.exclusion_key() : pos.key(); tte = TT.probe(posKey); - ttMove = RootNode ? Rml[MultiPVIdx].pv[0] : tte ? tte->move() : MOVE_NONE; + ttMove = RootNode ? RootMoves[PVIdx].pv[0] : tte ? tte->move() : MOVE_NONE; // At PV nodes we check for exact scores, while at non-PV nodes we check for // a fail high/low. Biggest advantage at probing at PV nodes is to have a @@ -829,10 +664,10 @@ namespace { if ( (move = (ss-1)->currentMove) != MOVE_NULL && (ss-1)->eval != VALUE_NONE && ss->eval != VALUE_NONE - && pos.captured_piece_type() == PIECE_TYPE_NONE + && !pos.captured_piece_type() && !is_special(move)) { - Square to = move_to(move); + Square to = to_sq(move); H.update_gain(pos.piece_on(to), to, -(ss-1)->eval - ss->eval); } @@ -842,7 +677,7 @@ namespace { && !inCheck && refinedValue + razor_margin(depth) < beta && ttMove == MOVE_NONE - && abs(beta) < VALUE_MATE_IN_PLY_MAX + && abs(beta) < VALUE_MATE_IN_MAX_PLY && !pos.has_pawn_on_7th(pos.side_to_move())) { Value rbeta = beta - razor_margin(depth); @@ -861,7 +696,7 @@ namespace { && depth < RazorDepth && !inCheck && refinedValue - futility_margin(depth, 0) >= beta - && abs(beta) < VALUE_MATE_IN_PLY_MAX + && abs(beta) < VALUE_MATE_IN_MAX_PLY && pos.non_pawn_material(pos.side_to_move())) return refinedValue - futility_margin(depth, 0); @@ -871,7 +706,7 @@ namespace { && depth > ONE_PLY && !inCheck && refinedValue >= beta - && abs(beta) < VALUE_MATE_IN_PLY_MAX + && abs(beta) < VALUE_MATE_IN_MAX_PLY && pos.non_pawn_material(pos.side_to_move())) { ss->currentMove = MOVE_NULL; @@ -893,7 +728,7 @@ namespace { if (nullValue >= beta) { // Do not return unproven mate scores - if (nullValue >= VALUE_MATE_IN_PLY_MAX) + if (nullValue >= VALUE_MATE_IN_MAX_PLY) nullValue = beta; if (depth < 6 * ONE_PLY) @@ -934,19 +769,21 @@ namespace { && !inCheck && !ss->skipNullMove && excludedMove == MOVE_NONE - && abs(beta) < VALUE_MATE_IN_PLY_MAX) + && abs(beta) < VALUE_MATE_IN_MAX_PLY) { Value rbeta = beta + 200; Depth rdepth = depth - ONE_PLY - 3 * ONE_PLY; assert(rdepth >= ONE_PLY); + assert((ss-1)->currentMove != MOVE_NONE); MovePicker mp(pos, ttMove, H, pos.captured_piece_type()); CheckInfo ci(pos); - while ((move = mp.get_next_move()) != MOVE_NONE) + while ((move = mp.next_move()) != MOVE_NONE) if (pos.pl_move_is_legal(move, ci.pinned)) { + ss->currentMove = move; pos.do_move(move, st, ci, pos.move_gives_check(move, ci)); value = -search(pos, ss+1, -rbeta, -rbeta+1, rdepth); pos.undo_move(move); @@ -972,7 +809,6 @@ namespace { split_point_start: // At split points actual search starts from here - // Initialize a MovePicker object for the current position MovePickerExt mp(pos, ttMove, depth, H, ss, PvNode ? -VALUE_INFINITE : beta); CheckInfo ci(pos); ss->bestMove = MOVE_NONE; @@ -981,20 +817,24 @@ split_point_start: // At split points actual search starts from here && !SpNode && depth >= SingularExtensionDepth[PvNode] && ttMove != MOVE_NONE - && !excludedMove // Do not allow recursive singular extension search + && !excludedMove // Recursive singular search is not allowed && (tte->type() & VALUE_TYPE_LOWER) && tte->depth() >= depth - 3 * ONE_PLY; if (SpNode) { lock_grab(&(sp->lock)); bestValue = sp->bestValue; + moveCount = sp->moveCount; + + assert(bestValue > -VALUE_INFINITE && moveCount > 0); } // Step 11. Loop through moves // Loop through all pseudo-legal moves until no moves remain or a beta cutoff occurs while ( bestValue < beta - && (move = mp.get_next_move()) != MOVE_NONE - && !thread.cutoff_occurred()) + && (move = mp.next_move()) != MOVE_NONE + && !thread.cutoff_occurred() + && !Signals.stop) { assert(is_ok(move)); @@ -1004,7 +844,7 @@ split_point_start: // At split points actual search starts from here // At root obey the "searchmoves" option and skip moves not listed in Root // Move List, as a consequence any illegal move is also skipped. In MultiPV // mode we also skip PV moves which have been already searched. - if (RootNode && !Rml.find(move, MultiPVIdx)) + if (RootNode && !count(RootMoves.begin() + PVIdx, RootMoves.end(), move)) continue; // At PV and SpNode nodes we want all moves to be legal since the beginning @@ -1021,25 +861,26 @@ split_point_start: // At split points actual search starts from here if (RootNode) { - // This is used by time management Signals.firstRootMove = (moveCount == 1); - // Save the current node count before the move is searched - nodes = pos.nodes_searched(); - - // For long searches send current move info to GUI - if (pos.thread() == 0 && elapsed_search_time() > 2000) - cout << "info" << depth_to_uci(depth) - << " currmove " << move - << " currmovenumber " << moveCount + MultiPVIdx << endl; + if (pos.thread() == 0 && elapsed_time() > 2000) + cout << "info depth " << depth / ONE_PLY + << " currmove " << move_to_uci(move, Chess960) + << " currmovenumber " << moveCount + PVIdx << endl; } isPvMove = (PvNode && moveCount <= 1); - givesCheck = pos.move_gives_check(move, ci); captureOrPromotion = pos.is_capture_or_promotion(move); + givesCheck = pos.move_gives_check(move, ci); + dangerous = givesCheck || is_dangerous(pos, move, captureOrPromotion); + ext = DEPTH_ZERO; - // Step 12. Decide the new search depth - ext = extension(pos, move, captureOrPromotion, givesCheck, &dangerous); + // Step 12. Extend checks and, in PV nodes, also dangerous moves + if (PvNode && dangerous) + ext = ONE_PLY; + + else if (givesCheck && pos.see_sign(move) >= 0) + ext = PvNode ? ONE_PLY : ONE_PLY / 2; // Singular extension search. If all moves but one fail low on a search of // (alpha-s, beta-s), and just one fails high on (alpha, beta), then that move @@ -1047,9 +888,9 @@ split_point_start: // At split points actual search starts from here // on all the other moves but the ttMove, if result is lower than ttValue minus // a margin then we extend ttMove. if ( singularExtensionNode + && !ext && move == ttMove - && pos.pl_move_is_legal(move, ci.pinned) - && ext < ONE_PLY) + && pos.pl_move_is_legal(move, ci.pinned)) { Value ttValue = value_from_tt(tte->value(), ss->ply); @@ -1076,12 +917,12 @@ split_point_start: // At split points actual search starts from here && !inCheck && !dangerous && move != ttMove - && !is_castle(move)) + && !is_castle(move) + && (bestValue > VALUE_MATED_IN_MAX_PLY || bestValue == -VALUE_INFINITE)) { // Move count based pruning if ( moveCount >= futility_move_count(depth) - && (!threatMove || !connected_threat(pos, move, threatMove)) - && bestValue > VALUE_MATED_IN_PLY_MAX) // FIXME bestValue is racy + && (!threatMove || !connected_threat(pos, move, threatMove))) { if (SpNode) lock_grab(&(sp->lock)); @@ -1094,25 +935,18 @@ split_point_start: // At split points actual search starts from here // but fixing this made program slightly weaker. Depth predictedDepth = newDepth - reduction(depth, moveCount); futilityValue = futilityBase + futility_margin(predictedDepth, moveCount) - + H.gain(pos.piece_on(move_from(move)), move_to(move)); + + H.gain(pos.piece_moved(move), to_sq(move)); if (futilityValue < beta) { if (SpNode) - { lock_grab(&(sp->lock)); - if (futilityValue > sp->bestValue) - sp->bestValue = bestValue = futilityValue; - } - else if (futilityValue > bestValue) - bestValue = futilityValue; continue; } // Prune moves with negative SEE at low depths if ( predictedDepth < 2 * ONE_PLY - && bestValue > VALUE_MATED_IN_PLY_MAX && pos.see_sign(move) < 0) { if (SpNode) @@ -1138,7 +972,7 @@ split_point_start: // At split points actual search starts from here // Step 15. Reduced depth search (LMR). If the move fails high will be // re-searched at full depth. - if ( depth > 3 * ONE_PLY + if ( depth > 4 * ONE_PLY && !isPvMove && !captureOrPromotion && !dangerous @@ -1147,11 +981,10 @@ split_point_start: // At split points actual search starts from here && ss->killers[1] != move) { ss->reduction = reduction(depth, moveCount); - Depth d = newDepth - ss->reduction; + Depth d = std::max(newDepth - ss->reduction, ONE_PLY); alpha = SpNode ? sp->alpha : alpha; - value = d < ONE_PLY ? -qsearch(pos, ss+1, -(alpha+1), -alpha, DEPTH_ZERO) - : - search(pos, ss+1, -(alpha+1), -alpha, d); + value = -search(pos, ss+1, -(alpha+1), -alpha, d); doFullDepthSearch = (value > alpha && ss->reduction != DEPTH_ZERO); ss->reduction = DEPTH_ZERO; @@ -1187,36 +1020,33 @@ split_point_start: // At split points actual search starts from here alpha = sp->alpha; } - // Finished searching the move. If StopRequest is true, the search + // Finished searching the move. If Signals.stop is true, the search // was aborted because the user interrupted the search or because we // ran out of time. In this case, the return value of the search cannot // be trusted, and we don't update the best move and/or PV. if (RootNode && !Signals.stop) { - // Remember searched nodes counts for this move - RootMove* rm = Rml.find(move); - rm->nodes += pos.nodes_searched() - nodes; + RootMove& rm = *find(RootMoves.begin(), RootMoves.end(), move); // PV move or new best move ? if (isPvMove || value > alpha) { - // Update PV - rm->score = value; - rm->extract_pv_from_tt(pos); + rm.score = value; + rm.extract_pv_from_tt(pos); // We record how often the best move has been changed in each // iteration. This information is used for time management: When // the best move changes frequently, we allocate some more time. if (!isPvMove && MultiPV == 1) - Rml.bestMoveChanges++; + BestMoveChanges++; } else // All other moves but the PV are set to the lowest value, this // is not a problem when sorting becuase sort is stable and move // position in the list is preserved, just the PV is pushed up. - rm->score = -VALUE_INFINITE; + rm.score = -VALUE_INFINITE; - } // RootNode + } if (value > bestValue) { @@ -1251,15 +1081,22 @@ split_point_start: // At split points actual search starts from here // Step 20. Check for mate and stalemate // All legal moves have been searched and if there are no legal moves, it // must be mate or stalemate. Note that we can have a false positive in - // case of StopRequest or thread.cutoff_occurred() are set, but this is + // case of Signals.stop or thread.cutoff_occurred() are set, but this is // harmless because return value is discarded anyhow in the parent nodes. // If we are in a singular extension search then return a fail low score. - if (!SpNode && !moveCount) - return excludedMove ? oldAlpha : inCheck ? value_mated_in(ss->ply) : VALUE_DRAW; + if (!moveCount) + return excludedMove ? oldAlpha : inCheck ? mated_in(ss->ply) : VALUE_DRAW; + + // If we have pruned all the moves without searching return a fail-low score + if (bestValue == -VALUE_INFINITE) + { + assert(!playedMoveCount); + + bestValue = alpha; + } // Step 21. Update tables - // If the search is not aborted, update the transposition table, - // history counters, and killer moves. + // Update transposition table entry, killers and history if (!SpNode && !Signals.stop && !thread.cutoff_occurred()) { move = bestValue <= oldAlpha ? MOVE_NONE : ss->bestMove; @@ -1268,16 +1105,27 @@ split_point_start: // At split points actual search starts from here TT.store(posKey, value_to_tt(bestValue, ss->ply), vt, depth, move, ss->eval, ss->evalMargin); - // Update killers and history only for non capture moves that fails high + // Update killers and history for non capture cut-off moves if ( bestValue >= beta - && !pos.is_capture_or_promotion(move)) + && !pos.is_capture_or_promotion(move) + && !inCheck) { if (move != ss->killers[0]) { ss->killers[1] = ss->killers[0]; ss->killers[0] = move; } - update_history(pos, move, depth, movesSearched, playedMoveCount); + + // Increase history value of the cut-off move + Value bonus = Value(int(depth) * int(depth)); + H.add(pos.piece_moved(move), to_sq(move), bonus); + + // Decrease history of all the other played non-capture moves + for (int i = 0; i < playedMoveCount - 1; i++) + { + Move m = movesSearched[i]; + H.add(pos.piece_moved(m), to_sq(m), -bonus); + } } } @@ -1294,20 +1142,20 @@ split_point_start: // At split points actual search starts from here return bestValue; } + // qsearch() is the quiescence search function, which is called by the main // search function when the remaining depth is zero (or, to be more precise, // less than ONE_PLY). template - Value qsearch(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth) { + Value qsearch(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth) { const bool PvNode = (NT == PV); assert(NT == PV || NT == NonPV); - assert(alpha >= -VALUE_INFINITE && alpha <= VALUE_INFINITE); - assert(beta >= -VALUE_INFINITE && beta <= VALUE_INFINITE); - assert(PvNode || alpha == beta - 1); - assert(depth <= 0); + assert(alpha >= -VALUE_INFINITE && alpha < beta && beta <= VALUE_INFINITE); + assert((alpha == beta - 1) || PvNode); + assert(depth <= DEPTH_ZERO); assert(pos.thread() >= 0 && pos.thread() < Threads.size()); StateInfo st; @@ -1323,7 +1171,7 @@ split_point_start: // At split points actual search starts from here ss->ply = (ss-1)->ply + 1; // Check for an instant draw or maximum ply reached - if (pos.is_draw() || ss->ply > PLY_MAX) + if (pos.is_draw() || ss->ply > MAX_PLY) return VALUE_DRAW; // Decide whether or not to include checks, this fixes also the type of @@ -1334,7 +1182,7 @@ split_point_start: // At split points actual search starts from here // Transposition table lookup. At PV nodes, we don't use the TT for // pruning, but only for move ordering. - tte = TT.probe(pos.get_key()); + tte = TT.probe(pos.key()); ttMove = (tte ? tte->move() : MOVE_NONE); if (!PvNode && tte && can_return_tt(tte, ttDepth, beta, ss->ply)) @@ -1366,7 +1214,7 @@ split_point_start: // At split points actual search starts from here if (bestValue >= beta) { if (!tte) - TT.store(pos.get_key(), value_to_tt(bestValue, ss->ply), VALUE_TYPE_LOWER, DEPTH_NONE, MOVE_NONE, ss->eval, evalMargin); + TT.store(pos.key(), value_to_tt(bestValue, ss->ply), VALUE_TYPE_LOWER, DEPTH_NONE, MOVE_NONE, ss->eval, evalMargin); return bestValue; } @@ -1374,7 +1222,6 @@ split_point_start: // At split points actual search starts from here if (PvNode && bestValue > alpha) alpha = bestValue; - // Futility pruning parameters, not needed when in check futilityBase = ss->eval + evalMargin + FutilityMarginQS; enoughMaterial = pos.non_pawn_material(pos.side_to_move()) > RookValueMidgame; } @@ -1383,12 +1230,12 @@ split_point_start: // At split points actual search starts from here // to search the moves. Because the depth is <= 0 here, only captures, // queen promotions and checks (only if depth >= DEPTH_QS_CHECKS) will // be generated. - MovePicker mp(pos, ttMove, depth, H, move_to((ss-1)->currentMove)); + MovePicker mp(pos, ttMove, depth, H, to_sq((ss-1)->currentMove)); CheckInfo ci(pos); // Loop through the moves until no moves remain or a beta cutoff occurs while ( bestValue < beta - && (move = mp.get_next_move()) != MOVE_NONE) + && (move = mp.next_move()) != MOVE_NONE) { assert(is_ok(move)); @@ -1404,7 +1251,7 @@ split_point_start: // At split points actual search starts from here && !pos.is_passed_pawn_push(move)) { futilityValue = futilityBase - + PieceValueEndgame[pos.piece_on(move_to(move))] + + PieceValueEndgame[pos.piece_on(to_sq(move))] + (is_enpassant(move) ? PawnValueEndgame : VALUE_ZERO); if (futilityValue < beta) @@ -1425,7 +1272,7 @@ split_point_start: // At split points actual search starts from here // Detect non-capture evasions that are candidate to be pruned evasionPrunable = !PvNode && inCheck - && bestValue > VALUE_MATED_IN_PLY_MAX + && bestValue > VALUE_MATED_IN_MAX_PLY && !pos.is_capture(move) && !pos.can_castle(pos.side_to_move()); @@ -1456,7 +1303,6 @@ split_point_start: // At split points actual search starts from here if (!pos.pl_move_is_legal(move, ci.pinned)) continue; - // Update current move ss->currentMove = move; // Make and search the move @@ -1482,14 +1328,14 @@ split_point_start: // At split points actual search starts from here // All legal moves have been searched. A special case: If we're in check // and no legal moves were found, it is checkmate. if (inCheck && bestValue == -VALUE_INFINITE) - return value_mated_in(ss->ply); + return mated_in(ss->ply); // Plies to mate from the root // Update transposition table move = bestValue <= oldAlpha ? MOVE_NONE : ss->bestMove; vt = bestValue <= oldAlpha ? VALUE_TYPE_UPPER : bestValue >= beta ? VALUE_TYPE_LOWER : VALUE_TYPE_EXACT; - TT.store(pos.get_key(), value_to_tt(bestValue, ss->ply), vt, ttDepth, move, ss->eval, evalMargin); + TT.store(pos.key(), value_to_tt(bestValue, ss->ply), vt, ttDepth, move, ss->eval, evalMargin); assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE); @@ -1509,9 +1355,9 @@ split_point_start: // At split points actual search starts from here Color them; Value futilityValue, bv = *bestValue; - from = move_from(move); - to = move_to(move); - them = flip(pos.side_to_move()); + from = from_sq(move); + to = to_sq(move); + them = ~pos.side_to_move(); ksq = pos.king_square(them); kingAtt = pos.attacks_from(ksq); pc = pos.piece_on(from); @@ -1570,14 +1416,14 @@ split_point_start: // At split points actual search starts from here assert(is_ok(m2)); // Case 1: The moving piece is the same in both moves - f2 = move_from(m2); - t1 = move_to(m1); + f2 = from_sq(m2); + t1 = to_sq(m1); if (f2 == t1) return true; // Case 2: The destination square for m2 was vacated by m1 - t2 = move_to(m2); - f1 = move_from(m1); + t2 = to_sq(m2); + f1 = from_sq(m1); if (t2 == f1) return true; @@ -1607,30 +1453,31 @@ split_point_start: // At split points actual search starts from here // value_to_tt() adjusts a mate score from "plies to mate from the root" to - // "plies to mate from the current ply". Non-mate scores are unchanged. + // "plies to mate from the current position". Non-mate scores are unchanged. // The function is called before storing a value to the transposition table. Value value_to_tt(Value v, int ply) { - if (v >= VALUE_MATE_IN_PLY_MAX) + if (v >= VALUE_MATE_IN_MAX_PLY) return v + ply; - if (v <= VALUE_MATED_IN_PLY_MAX) + if (v <= VALUE_MATED_IN_MAX_PLY) return v - ply; return v; } - // value_from_tt() is the inverse of value_to_tt(): It adjusts a mate score from - // the transposition table to a mate score corrected for the current ply. + // value_from_tt() is the inverse of value_to_tt(): It adjusts a mate score + // from the transposition table (where refers to the plies to mate/be mated + // from current position) to "plies to mate/be mated from the root". Value value_from_tt(Value v, int ply) { - if (v >= VALUE_MATE_IN_PLY_MAX) + if (v >= VALUE_MATE_IN_MAX_PLY) return v - ply; - if (v <= VALUE_MATED_IN_PLY_MAX) + if (v <= VALUE_MATED_IN_MAX_PLY) return v + ply; return v; @@ -1649,10 +1496,10 @@ split_point_start: // At split points actual search starts from here Square mfrom, mto, tfrom, tto; - mfrom = move_from(m); - mto = move_to(m); - tfrom = move_from(threat); - tto = move_to(threat); + mfrom = from_sq(m); + mto = to_sq(m); + tfrom = from_sq(threat); + tto = to_sq(threat); // Case 1: Don't prune moves which move the threatened piece if (mfrom == tto) @@ -1677,24 +1524,24 @@ split_point_start: // At split points actual search starts from here } - // can_return_tt() returns true if a transposition table score - // can be used to cut-off at a given point in search. + // can_return_tt() returns true if a transposition table score can be used to + // cut-off at a given point in search. bool can_return_tt(const TTEntry* tte, Depth depth, Value beta, int ply) { Value v = value_from_tt(tte->value(), ply); return ( tte->depth() >= depth - || v >= std::max(VALUE_MATE_IN_PLY_MAX, beta) - || v < std::min(VALUE_MATED_IN_PLY_MAX, beta)) + || v >= std::max(VALUE_MATE_IN_MAX_PLY, beta) + || v < std::min(VALUE_MATED_IN_MAX_PLY, beta)) && ( ((tte->type() & VALUE_TYPE_LOWER) && v >= beta) || ((tte->type() & VALUE_TYPE_UPPER) && v < beta)); } - // refine_eval() returns the transposition table score if - // possible otherwise falls back on static position evaluation. + // refine_eval() returns the transposition table score if possible, otherwise + // falls back on static position evaluation. Value refine_eval(const TTEntry* tte, Value defaultEval, int ply) { @@ -1710,38 +1557,17 @@ split_point_start: // At split points actual search starts from here } - // update_history() registers a good move that produced a beta-cutoff - // in history and marks as failures all the other moves of that ply. - - void update_history(const Position& pos, Move move, Depth depth, - Move movesSearched[], int moveCount) { - Move m; - Value bonus = Value(int(depth) * int(depth)); - - H.update(pos.piece_on(move_from(move)), move_to(move), bonus); - - for (int i = 0; i < moveCount - 1; i++) - { - m = movesSearched[i]; - - assert(m != move); - - H.update(pos.piece_on(move_from(m)), move_to(m), -bonus); - } - } - - // current_search_time() returns the number of milliseconds which have passed // since the beginning of the current search. - int elapsed_search_time(int set) { + int elapsed_time(bool reset) { static int searchStartTime; - if (set) - searchStartTime = set; + if (reset) + searchStartTime = system_time(); - return get_system_time() - searchStartTime; + return system_time() - searchStartTime; } @@ -1756,10 +1582,10 @@ split_point_start: // At split points actual search starts from here std::stringstream s; - if (abs(v) < VALUE_MATE - PLY_MAX * ONE_PLY) - s << " score cp " << int(v) * 100 / int(PawnValueMidgame); // Scale to centipawns + if (abs(v) < VALUE_MATE_IN_MAX_PLY) + s << "cp " << v * 100 / int(PawnValueMidgame); else - s << " score mate " << (v > 0 ? VALUE_MATE - v + 1 : -VALUE_MATE - v) / 2; + s << "mate " << (v > 0 ? VALUE_MATE - v + 1 : -VALUE_MATE - v) / 2; s << (v >= beta ? " lowerbound" : v <= alpha ? " upperbound" : ""); @@ -1767,56 +1593,49 @@ split_point_start: // At split points actual search starts from here } - // speed_to_uci() returns a string with time stats of current search suitable - // to be sent to UCI gui. - - string speed_to_uci(int64_t nodes) { - - std::stringstream s; - int t = elapsed_search_time(); - - s << " nodes " << nodes - << " nps " << (t > 0 ? int(nodes * 1000 / t) : 0) - << " time " << t; - - return s.str(); - } - - - // pv_to_uci() returns a string with information on the current PV line - // formatted according to UCI specification. - - string pv_to_uci(const Move pv[], int pvNum, bool chess960) { - - std::stringstream s; - - s << " multipv " << pvNum << " pv " << set960(chess960); - - for ( ; *pv != MOVE_NONE; pv++) - s << *pv << " "; - - return s.str(); - } - - - // depth_to_uci() returns a string with information on the current depth and - // seldepth formatted according to UCI specification. + // pv_info_to_uci() sends search info to GUI. UCI protocol requires to send all + // the PV lines also if are still to be searched and so refer to the previous + // search score. - string depth_to_uci(Depth depth) { + void pv_info_to_uci(const Position& pos, int depth, Value alpha, Value beta) { - std::stringstream s; - - // Retrieve max searched depth among threads + int t = elapsed_time(); int selDepth = 0; + for (int i = 0; i < Threads.size(); i++) if (Threads[i].maxPly > selDepth) selDepth = Threads[i].maxPly; - s << " depth " << depth / ONE_PLY << " seldepth " << selDepth; + for (size_t i = 0; i < std::min(UCIMultiPV, RootMoves.size()); i++) + { + bool updated = (i <= PVIdx); - return s.str(); + if (depth == 1 && !updated) + continue; + + int d = (updated ? depth : depth - 1); + Value v = (updated ? RootMoves[i].score : RootMoves[i].prevScore); + std::stringstream s; + + for (int j = 0; RootMoves[i].pv[j] != MOVE_NONE; j++) + s << " " << move_to_uci(RootMoves[i].pv[j], Chess960); + + cout << "info depth " << d + << " seldepth " << selDepth + << " score " << (i == PVIdx ? score_to_uci(v, alpha, beta) : score_to_uci(v)) + << " nodes " << pos.nodes_searched() + << " nps " << (t > 0 ? pos.nodes_searched() * 1000 / t : 0) + << " time " << t + << " multipv " << i + 1 + << " pv" << s.str() << endl; + } } + + // pv_info_to_log() writes human-readable search information to the log file + // (which is created when the UCI parameter "Use Search Log" is "true"). It + // uses the two below helpers to pretty format time and score respectively. + string time_to_string(int millisecs) { const int MSecMinute = 1000 * 60; @@ -1831,7 +1650,8 @@ split_point_start: // At split points actual search starts from here if (hours) s << hours << ':'; - s << std::setfill('0') << std::setw(2) << minutes << ':' << std::setw(2) << seconds; + s << std::setfill('0') << std::setw(2) << minutes << ':' + << std::setw(2) << seconds; return s.str(); } @@ -1839,224 +1659,185 @@ split_point_start: // At split points actual search starts from here std::stringstream s; - if (v >= VALUE_MATE_IN_PLY_MAX) + if (v >= VALUE_MATE_IN_MAX_PLY) s << "#" << (VALUE_MATE - v + 1) / 2; - else if (v <= VALUE_MATED_IN_PLY_MAX) + else if (v <= VALUE_MATED_IN_MAX_PLY) s << "-#" << (VALUE_MATE + v) / 2; else - s << std::setprecision(2) << std::fixed << std::showpos << float(v) / PawnValueMidgame; + s << std::setprecision(2) << std::fixed << std::showpos + << float(v) / PawnValueMidgame; return s.str(); } - - // pretty_pv() creates a human-readable string from a position and a PV. - // It is used to write search information to the log file (which is created - // when the UCI parameter "Use Search Log" is "true"). - - string pretty_pv(Position& pos, int depth, Value value, int time, Move pv[]) { + void pv_info_to_log(Position& pos, int depth, Value value, int time, Move pv[]) { const int64_t K = 1000; const int64_t M = 1000000; - const int startColumn = 28; - const size_t maxLength = 80 - startColumn; - StateInfo state[PLY_MAX_PLUS_2], *st = state; + StateInfo state[MAX_PLY_PLUS_2], *st = state; Move* m = pv; - string san; + string san, padding; + size_t length; std::stringstream s; - size_t length = 0; - // First print depth, score, time and searched nodes... - s << set960(pos.is_chess960()) - << std::setw(2) << depth + s << std::setw(2) << depth << std::setw(8) << score_to_string(value) << std::setw(8) << time_to_string(time); if (pos.nodes_searched() < M) s << std::setw(8) << pos.nodes_searched() / 1 << " "; + else if (pos.nodes_searched() < K * M) s << std::setw(7) << pos.nodes_searched() / K << "K "; + else s << std::setw(7) << pos.nodes_searched() / M << "M "; - // ...then print the full PV line in short algebraic notation + padding = string(s.str().length(), ' '); + length = padding.length(); + while (*m != MOVE_NONE) { san = move_to_san(pos, *m); - length += san.length() + 1; - if (length > maxLength) + if (length + san.length() > 80) { - length = san.length() + 1; - s << "\n" + string(startColumn, ' '); + s << "\n" + padding; + length = padding.length(); } + s << san << ' '; + length += san.length() + 1; pos.do_move(*m++, *st++); } - // Restore original position before to leave - while (m != pv) pos.undo_move(*--m); + while (m != pv) + pos.undo_move(*--m); - return s.str(); + Log l(Options["Search Log Filename"]); + l << s.str() << endl; } // When playing with strength handicap choose best move among the MultiPV set // using a statistical rule dependent on SkillLevel. Idea by Heinz van Saanen. - void do_skill_level(Move* best, Move* ponder) { + Move do_skill_level() { assert(MultiPV > 1); static RKISS rk; - // Rml list is already sorted by score in descending order - int s; - int max_s = -VALUE_INFINITE; - int size = std::min(MultiPV, (int)Rml.size()); - int max = Rml[0].score; - int var = std::min(max - Rml[size - 1].score, int(PawnValueMidgame)); - int wk = 120 - 2 * SkillLevel; - - // PRNG sequence should be non deterministic - for (int i = abs(get_system_time() % 50); i > 0; i--) + // PRNG sequence should be not deterministic + for (int i = abs(system_time() % 50); i > 0; i--) rk.rand(); - // Choose best move. For each move's score we add two terms both dependent - // on wk, one deterministic and bigger for weaker moves, and one random, + // RootMoves are already sorted by score in descending order + size_t size = std::min(MultiPV, RootMoves.size()); + int variance = std::min(RootMoves[0].score - RootMoves[size - 1].score, PawnValueMidgame); + int weakness = 120 - 2 * SkillLevel; + int max_s = -VALUE_INFINITE; + Move best = MOVE_NONE; + + // Choose best move. For each move score we add two terms both dependent on + // weakness, one deterministic and bigger for weaker moves, and one random, // then we choose the move with the resulting highest score. - for (int i = 0; i < size; i++) + for (size_t i = 0; i < size; i++) { - s = Rml[i].score; + int s = RootMoves[i].score; // Don't allow crazy blunders even at very low skills - if (i > 0 && Rml[i-1].score > s + EasyMoveMargin) + if (i > 0 && RootMoves[i-1].score > s + EasyMoveMargin) break; - // This is our magical formula - s += ((max - s) * wk + var * (rk.rand() % wk)) / 128; + // This is our magic formula + s += ( weakness * int(RootMoves[0].score - s) + + variance * (rk.rand() % weakness)) / 128; if (s > max_s) { max_s = s; - *best = Rml[i].pv[0]; - *ponder = Rml[i].pv[1]; + best = RootMoves[i].pv[0]; } } + return best; } +} // namespace - /// RootMove and RootMoveList method's definitions - - void RootMoveList::init(Position& pos, Move rootMoves[]) { - - Move* sm; - bestMoveChanges = 0; - clear(); - - // Generate all legal moves and add them to RootMoveList - for (MoveList ml(pos); !ml.end(); ++ml) - { - // If we have a rootMoves[] list then verify the move - // is in the list before to add it. - for (sm = rootMoves; *sm && *sm != ml.move(); sm++) {} - - if (sm != rootMoves && *sm != ml.move()) - continue; - - RootMove rm; - rm.pv.push_back(ml.move()); - rm.pv.push_back(MOVE_NONE); - rm.score = rm.prevScore = -VALUE_INFINITE; - rm.nodes = 0; - push_back(rm); - } - } - - RootMove* RootMoveList::find(const Move& m, int startIndex) { - - for (size_t i = startIndex; i < size(); i++) - if ((*this)[i].pv[0] == m) - return &(*this)[i]; - - return NULL; - } - - - // extract_pv_from_tt() builds a PV by adding moves from the transposition table. - // We consider also failing high nodes and not only VALUE_TYPE_EXACT nodes. This - // allow to always have a ponder move even when we fail high at root and also a - // long PV to print that is important for position analysis. - void RootMove::extract_pv_from_tt(Position& pos) { +/// RootMove::extract_pv_from_tt() builds a PV by adding moves from the TT table. +/// We consider also failing high nodes and not only VALUE_TYPE_EXACT nodes so +/// to allow to always have a ponder move even when we fail high at root, and +/// a long PV to print that is important for position analysis. - StateInfo state[PLY_MAX_PLUS_2], *st = state; - TTEntry* tte; - int ply = 1; - Move m = pv[0]; +void RootMove::extract_pv_from_tt(Position& pos) { - assert(m != MOVE_NONE && pos.is_pseudo_legal(m)); + StateInfo state[MAX_PLY_PLUS_2], *st = state; + TTEntry* tte; + int ply = 1; + Move m = pv[0]; - pv.clear(); - pv.push_back(m); - pos.do_move(m, *st++); + assert(m != MOVE_NONE && pos.is_pseudo_legal(m)); - while ( (tte = TT.probe(pos.get_key())) != NULL - && tte->move() != MOVE_NONE - && pos.is_pseudo_legal(tte->move()) - && pos.pl_move_is_legal(tte->move(), pos.pinned_pieces()) - && ply < PLY_MAX - && (!pos.is_draw() || ply < 2)) - { - pv.push_back(tte->move()); - pos.do_move(tte->move(), *st++); - ply++; - } - pv.push_back(MOVE_NONE); + pv.clear(); + pv.push_back(m); + pos.do_move(m, *st++); - do pos.undo_move(pv[--ply]); while (ply); + while ( (tte = TT.probe(pos.key())) != NULL + && tte->move() != MOVE_NONE + && pos.is_pseudo_legal(tte->move()) + && pos.pl_move_is_legal(tte->move(), pos.pinned_pieces()) + && ply < MAX_PLY + && (!pos.is_draw() || ply < 2)) + { + pv.push_back(tte->move()); + pos.do_move(tte->move(), *st++); + ply++; } + pv.push_back(MOVE_NONE); + do pos.undo_move(pv[--ply]); while (ply); +} - // insert_pv_in_tt() is called at the end of a search iteration, and inserts - // the PV back into the TT. This makes sure the old PV moves are searched - // first, even if the old TT entries have been overwritten. - void RootMove::insert_pv_in_tt(Position& pos) { +/// RootMove::insert_pv_in_tt() is called at the end of a search iteration, and +/// inserts the PV back into the TT. This makes sure the old PV moves are searched +/// first, even if the old TT entries have been overwritten. - StateInfo state[PLY_MAX_PLUS_2], *st = state; - TTEntry* tte; - Key k; - Value v, m = VALUE_NONE; - int ply = 0; +void RootMove::insert_pv_in_tt(Position& pos) { - assert(pv[0] != MOVE_NONE && pos.is_pseudo_legal(pv[0])); + StateInfo state[MAX_PLY_PLUS_2], *st = state; + TTEntry* tte; + Key k; + Value v, m = VALUE_NONE; + int ply = 0; - do { - k = pos.get_key(); - tte = TT.probe(k); + assert(pv[ply] != MOVE_NONE && pos.is_pseudo_legal(pv[ply])); - // Don't overwrite existing correct entries - if (!tte || tte->move() != pv[ply]) - { - v = (pos.in_check() ? VALUE_NONE : evaluate(pos, m)); - TT.store(k, VALUE_NONE, VALUE_TYPE_NONE, DEPTH_NONE, pv[ply], v, m); - } - pos.do_move(pv[ply], *st++); + do { + k = pos.key(); + tte = TT.probe(k); - } while (pv[++ply] != MOVE_NONE); + // Don't overwrite existing correct entries + if (!tte || tte->move() != pv[ply]) + { + v = (pos.in_check() ? VALUE_NONE : evaluate(pos, m)); + TT.store(k, VALUE_NONE, VALUE_TYPE_NONE, DEPTH_NONE, pv[ply], v, m); + } + pos.do_move(pv[ply], *st++); - do pos.undo_move(pv[--ply]); while (ply); - } + } while (pv[++ply] != MOVE_NONE); -} // namespace + do pos.undo_move(pv[--ply]); while (ply); +} -// Thread::idle_loop() is where the thread is parked when it has no work to do. -// The parameter 'sp', if non-NULL, is a pointer to an active SplitPoint object -// for which the thread is the master. +/// Thread::idle_loop() is where the thread is parked when it has no work to do. +/// The parameter 'sp', if non-NULL, is a pointer to an active SplitPoint object +/// for which the thread is the master. void Thread::idle_loop(SplitPoint* sp) { @@ -2070,7 +1851,6 @@ void Thread::idle_loop(SplitPoint* sp) { { assert((!sp && threadID) || Threads.use_sleeping_threads()); - // Slave thread should exit as soon as do_terminate flag raises if (do_terminate) { assert(!sp); @@ -2103,11 +1883,11 @@ void Thread::idle_loop(SplitPoint* sp) { assert(!do_terminate); // Copy split point position and search stack and call search() - SearchStack ss[PLY_MAX_PLUS_2]; + Stack ss[MAX_PLY_PLUS_2]; SplitPoint* tsp = splitPoint; Position pos(*tsp->pos, threadID); - memcpy(ss, tsp->ss - 1, 4 * sizeof(SearchStack)); + memcpy(ss, tsp->ss - 1, 4 * sizeof(Stack)); (ss+1)->sp = tsp; if (tsp->nodeType == Root) @@ -2145,23 +1925,21 @@ void Thread::idle_loop(SplitPoint* sp) { } -// do_timer_event() is called by the timer thread when the timer triggers +/// check_time() is called by the timer thread when the timer triggers. It is +/// used to print debug info and, more important, to detect when we are out of +/// available time and so stop the search. -void do_timer_event() { +void check_time() { static int lastInfoTime; - int e = elapsed_search_time(); + int e = elapsed_time(); - // Print debug information every one second - if (!lastInfoTime || get_system_time() - lastInfoTime >= 1000) + if (system_time() - lastInfoTime >= 1000 || !lastInfoTime) { - lastInfoTime = get_system_time(); - - dbg_print_mean(); - dbg_print_hit_rate(); + lastInfoTime = system_time(); + dbg_print(); } - // Should we stop the search? if (Limits.ponder) return; @@ -2169,11 +1947,10 @@ void do_timer_event() { && !Signals.failedLowAtRoot && e > TimeMgr.available_time(); - bool noMoreTime = e > TimeMgr.maximum_time() + bool noMoreTime = e > TimeMgr.maximum_time() - 2 * TimerResolution || stillAtFirstMove; - if ( (Limits.useTimeManagement() && noMoreTime) - || (Limits.maxTime && e >= Limits.maxTime) - /* missing nodes limit */ ) // FIXME + if ( (Limits.use_time_management() && noMoreTime) + || (Limits.maxTime && e >= Limits.maxTime)) Signals.stop = true; }