X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=970ed184d5ffc0a43c61c6ab9596e3ffd0315fee;hp=d93fbdf79635d3b14a854fa979e87babb802df7c;hb=842efefcad9c6100d0376e20c59264852d225920;hpb=f902ddaa89440cd2f3a981cc1dfbfad609a9e0fb diff --git a/src/search.cpp b/src/search.cpp index d93fbdf7..970ed184 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, Value alpha, Value beta, int pvLine = 0); int64_t nodes; Value pv_score; @@ -146,10 +146,10 @@ namespace { typedef std::vector Base; RootMoveList(Position& pos, Move searchMoves[]); - void set_non_pv_scores(const Position& pos); + void set_non_pv_scores(const Position& pos, Move ttm, SearchStack* ss); 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); } }; @@ -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 @@ -304,7 +313,7 @@ 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); int current_search_time(); @@ -364,15 +373,15 @@ 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. @@ -414,7 +423,7 @@ 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()); @@ -513,6 +522,9 @@ bool think(Position& pos, bool infinite, bool ponder, int time[], int increment[ << move_to_san(pos, ponderMove) // Works also with MOVE_NONE << endl; + // Return from think() with unchanged position + pos.undo_move(bestMove); + LogFile.close(); } @@ -544,6 +556,7 @@ namespace { Depth depth; Move EasyMove = MOVE_NONE; Value value, alpha = -VALUE_INFINITE, beta = VALUE_INFINITE; + int researchCountFL, researchCountFH; // Moves to search are verified, scored and sorted RootMoveList rml(pos, searchMoves); @@ -600,8 +613,50 @@ namespace { depth = (Iteration - 2) * ONE_PLY + InitialDepth; - // Search to the current depth, rml is updated and sorted - value = root_search(pos, ss, alpha, beta, depth, rml); + researchCountFL = researchCountFH = 0; + + // We start with small aspiration window and in case of fail high/low, we + // research with bigger window until we are not failing high/low anymore. + while (true) + { + // Sort the moves before to (re)search + rml.set_non_pv_scores(pos, rml[0].pv[0], ss); + rml.sort(); + + // Search to the current depth, rml is updated and sorted + value = root_search(pos, ss, alpha, beta, depth, rml); + + // 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); + + if (StopRequest) + break; + + assert(value >= alpha); + + if (value >= beta) + { + // Prepare for a research after a fail high, each time with a wider window + beta = Min(beta + AspirationDelta * (1 << researchCountFH), VALUE_INFINITE); + researchCountFH++; + } + else if (value <= alpha) + { + AspirationFailLow = true; + StopOnPonderhit = false; + + // Prepare for a research after a fail low, each time with a wider window + alpha = Max(alpha - AspirationDelta * (1 << researchCountFL), -VALUE_INFINITE); + researchCountFL++; + } + else + break; + } if (StopRequest) break; // Value cannot be trusted. Break out immediately! @@ -624,7 +679,7 @@ namespace { stopSearch = true; // Stop search early when the last two iterations returned a mate score - if ( Iteration >= 6 + if ( Iteration >= 6 && abs(ValueByIteration[Iteration]) >= abs(VALUE_MATE) - 100 && abs(ValueByIteration[Iteration-1]) >= abs(VALUE_MATE) - 100) stopSearch = true; @@ -673,25 +728,33 @@ namespace { Value root_search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth, RootMoveList& rml) { + + assert(alpha >= -VALUE_INFINITE && alpha <= VALUE_INFINITE); + assert(beta > alpha && beta <= VALUE_INFINITE); + assert(pos.thread() >= 0 && pos.thread() < ThreadsMgr.active_threads()); + + Move movesSearched[MOVES_MAX]; StateInfo st; - CheckInfo ci(pos); - int64_t nodes; + Key posKey; Move move; Depth ext, newDepth; - Value value, oldAlpha; - bool isCheck, moveIsCheck, captureOrPromotion, dangerous; - int researchCountFH, researchCountFL; + ValueType vt; + Value bestValue, value, oldAlpha; + bool isCheck, moveIsCheck, captureOrPromotion, dangerous, isPvMove; + int moveCount = 0; - researchCountFH = researchCountFL = 0; + bestValue = value = -VALUE_INFINITE; oldAlpha = alpha; isCheck = pos.is_check(); // Step 1. Initialize node (polling is omitted at root) ss->currentMove = ss->bestMove = MOVE_NONE; + (ss+2)->killers[0] = (ss+2)->killers[1] = (ss+2)->mateKiller = 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) + posKey = pos.get_key(); // Step 5. Evaluate the position statically // At root we do this only to get reference value for child nodes @@ -703,210 +766,181 @@ namespace { // 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(); + CheckInfo ci(pos); + int64_t nodes; + RootMoveList::iterator rm = rml.begin(); + bestValue = alpha; - // 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); + // Step 10. Loop through moves + // Loop through all legal moves until no moves remain or a beta cutoff occurs + while ( bestValue < beta + && rm != rml.end() + && !StopRequest) + { + move = ss->currentMove = rm->pv[0]; + movesSearched[moveCount++] = move; + isPvMove = (moveCount <= MultiPV); - // Save the current node count before the move is searched - nodes = pos.nodes_searched(); + // This is used by time management + FirstRootMove = (rm == rml.begin()); - // 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; - } + // Save the current node count before the move is searched + nodes = pos.nodes_searched(); - // 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 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 " << i + 1 << endl; + if (current_search_time() >= 1000) + cout << "info currmove " << move + << " currmovenumber " << moveCount << endl; - moveIsCheck = pos.move_is_check(move); - captureOrPromotion = pos.move_is_capture_or_promotion(move); + 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 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 12. Futility pruning (omitted at root) + // Step 13. Make the move + pos.do_move(move, st, ci, moveIsCheck); - // Step extra. Fail high loop - // If move fails high, we research with bigger window until we are not failing - // high anymore. - value = -VALUE_INFINITE; + // Step extra. pv search + // We do pv search for PV moves + if (isPvMove) + { + // Aspiration window is disabled in multi-pv case + if (MultiPV > 1) + alpha = -VALUE_INFINITE; - while (1) + // 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 + && !captureOrPromotion + && !dangerous + && !move_is_castle(move) + && ss->killers[0] != move + && ss->killers[1] != move) { - // Step 13. Make the move - pos.do_move(move, st, ci, moveIsCheck); + ss->reduction = reduction(depth, moveCount - MultiPV + 1); - // 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) + if (ss->reduction) { - // Aspiration window is disabled in multi-pv case - if (MultiPV > 1) - alpha = -VALUE_INFINITE; + Depth d = newDepth - ss->reduction; + value = -search(pos, ss+1, -(alpha+1), -alpha, d, 1); - // 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); - } + doFullDepthSearch = (value > alpha); } + ss->reduction = DEPTH_ZERO; // Restore original reduction + } - // 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; + // 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); - // Remember searched nodes counts for this move - rml[i].nodes += pos.nodes_searched() - nodes; + // 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); + } + } - assert(value >= -VALUE_INFINITE && value <= VALUE_INFINITE); - assert(value < beta); + // Step 16. Undo move + pos.undo_move(move); - // 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! + assert(value > -VALUE_INFINITE && value < VALUE_INFINITE); - // Update PV - ss->bestMove = move; - rml[i].pv_score = value; - rml[i].extract_pv_from_tt(pos); + // 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; - // 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]++; + // Remember searched nodes counts for this move + rm->nodes += pos.nodes_searched() - nodes; - // 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); + // Step 17. Check for new best move + if (!isPvMove && value <= alpha) + rm->pv_score = -VALUE_INFINITE; + else + { + // PV move or new best move! - for (int j = 0; j < Min(MultiPV, (int)rml.size()); j++) - cout << rml[j].pv_info_to_uci(pos, alpha, beta, j) << endl; + // Update PV + ss->bestMove = move; + rm->pv_score = value; + rm->extract_pv_from_tt(pos); - // 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; + // 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 (!isPvMove && MultiPV == 1) + BestMoveChangesByIteration[Iteration]++; - } // PV move or new best move + // 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(moveCount); - assert(alpha >= oldAlpha); + for (int j = 0; j < Min(MultiPV, (int)rml.size()); j++) + cout << rml[j].pv_info_to_uci(pos, alpha, beta, j) << endl; - AspirationFailLow = (alpha == oldAlpha); + // 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 = bestValue = value; + } + else // Set alpha equal to minimum score among the PV lines + alpha = bestValue = rml[Min(moveCount, MultiPV) - 1].pv_score; // FIXME why moveCount? - if (AspirationFailLow && StopOnPonderhit) - StopOnPonderhit = false; + } // PV move or new best move - } // Root moves loop + ++rm; - // Can we exit fail low loop ? - if (StopRequest || !AspirationFailLow) - break; + } // Root moves loop - // Prepare for a research after a fail low, each time with a wider window - oldAlpha = alpha = Max(alpha - AspirationDelta * (1 << researchCountFL), -VALUE_INFINITE); - researchCountFL++; + // Step 20. Update tables + // If the search is not aborted, update the transposition table, + // history counters, and killer moves. + if (!StopRequest) + { + move = bestValue <= oldAlpha ? MOVE_NONE : ss->bestMove; + vt = bestValue <= oldAlpha ? VALUE_TYPE_UPPER + : bestValue >= beta ? VALUE_TYPE_LOWER : VALUE_TYPE_EXACT; - } // Fail low loop + TT.store(posKey, value_to_tt(bestValue, 0), vt, depth, move, ss->eval, ss->evalMargin); - // Sort the moves before to return - rml.sort(); + // Update killers and history only for non capture moves that fails high + if ( bestValue >= beta + && !pos.move_is_capture_or_promotion(move)) + { + update_history(pos, move, depth, movesSearched, moveCount); + update_killers(move, ss->killers); + } + } - // 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); + assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE); - return alpha; + return bestValue; } @@ -1384,7 +1418,7 @@ split_point_start: // At split points actual search starts from here && !pos.move_is_capture_or_promotion(move)) { update_history(pos, move, depth, movesSearched, moveCount); - update_killers(move, ss); + update_killers(move, ss->killers); } } @@ -1885,8 +1919,9 @@ 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++) { @@ -1895,7 +1930,7 @@ 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); } } @@ -1903,13 +1938,13 @@ 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) { + void update_killers(Move m, Move killers[]) { - if (m == ss->killers[0]) + if (m == killers[0]) return; - ss->killers[1] = ss->killers[0]; - ss->killers[0] = m; + killers[1] = killers[0]; + killers[0] = m; } @@ -1923,7 +1958,7 @@ 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)); + H.update_gain(pos.piece_on(move_to(m)), move_to(m), -(before + after)); } @@ -1993,7 +2028,7 @@ 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; @@ -2610,7 +2645,7 @@ split_point_start: // At split points actual search starts from here // formatted according to UCI specification and eventually writes the info // to a log file. It is called at each iteration or after a new pv is found. - std::string RootMove::pv_info_to_uci(const Position& pos, Value alpha, Value beta, int pvLine) { + std::string RootMove::pv_info_to_uci(Position& pos, Value alpha, Value beta, int pvLine) { std::stringstream s, l; Move* m = pv; @@ -2651,7 +2686,7 @@ split_point_start: // At split points actual search starts from here ss[0].eval = ss[0].evalMargin = VALUE_NONE; // Generate all legal moves - MoveStack* last = generate_moves(pos, mlist); + MoveStack* last = generate(pos, mlist); // Add each move to the RootMoveList's vector for (MoveStack* cur = mlist; cur != last; cur++) @@ -2682,11 +2717,11 @@ split_point_start: // At split points actual search starts from here // 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) + void RootMoveList::set_non_pv_scores(const Position& pos, Move ttm, SearchStack* ss) { Move move; Value score = VALUE_ZERO; - MovePicker mp(pos, MOVE_NONE, ONE_PLY, H); + MovePicker mp(pos, ttm, ONE_PLY, H, ss); while ((move = mp.get_next_move()) != MOVE_NONE) for (Base::iterator it = begin(); it != end(); ++it)