X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=037c44ddfe37a483a373c34c8b9eed1f3246c4e5;hp=702adc53dbdae3e81508f78e88c08cc12556630d;hb=bb3427ca85bdb20b4c8af12b63f635d03c5e9146;hpb=c56a7ee803bcb3c2c6072ee4ea196eb4eb9bdf00 diff --git a/src/search.cpp b/src/search.cpp index 702adc53..037c44dd 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -42,6 +42,16 @@ 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; + Position RootPosition; +} namespace { @@ -74,7 +84,7 @@ namespace { // RootMoveList struct is mainly a std::vector of RootMove objects struct RootMoveList : public std::vector { - void init(Position& pos, Move searchMoves[]); + void init(Position& pos, Move rootMoves[]); RootMove* find(const Move& m, int startIndex = 0); int bestMoveChanges; @@ -162,9 +172,7 @@ namespace { int MultiPV, UCIMultiPV, MultiPVIdx; // Time management variables - bool StopOnPonderhit, FirstRootMove, StopRequest, QuitRequest, AspirationFailLow; TimeManager TimeMgr; - SearchLimits Limits; // Skill level adjustment int SkillLevel; @@ -176,7 +184,7 @@ namespace { /// Local functions - Move id_loop(Position& pos, Move searchMoves[], Move* ponderMove); + Move id_loop(Position& pos, Move rootMoves[], Move* ponderMove); template Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth); @@ -200,7 +208,6 @@ namespace { 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); - void wait_for_stop_or_ponderhit(); // 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 @@ -293,7 +300,7 @@ namespace { /// init_search() is called during startup to initialize various lookup tables -void init_search() { +void Search::init() { int d; // depth (ONE_PLY == 2) int hd; // half depth (ONE_PLY == 1) @@ -321,7 +328,7 @@ void init_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 perft(Position& pos, Depth depth) { +int64_t Search::perft(Position& pos, Depth depth) { StateInfo st; int64_t sum = 0; @@ -351,17 +358,15 @@ int64_t perft(Position& pos, Depth depth) { /// variables, and calls id_loop(). It returns false when a "quit" command is /// received during the search. -bool think(Position& pos, const SearchLimits& limits, Move searchMoves[]) { +void Search::think() { static Book book; // Defined static to initialize the PRNG only once + Position& pos = RootPosition; + // Save "search start" time and reset elapsed time to zero elapsed_search_time(get_system_time()); - // Initialize global search-related variables - StopOnPonderhit = StopRequest = QuitRequest = AspirationFailLow = false; - Limits = limits; - // Set output stream mode: normal or chess960. Castling notation is different cout << set960(pos.is_chess960()); @@ -374,11 +379,11 @@ bool think(Position& pos, const SearchLimits& limits, Move searchMoves[]) { Move bookMove = book.probe(pos, Options["Best Book Move"].value()); if (bookMove != MOVE_NONE) { - if (Limits.ponder) - wait_for_stop_or_ponderhit(); + if (!Signals.stop && (Limits.ponder || Limits.infinite)) + Threads.wait_for_stop_or_ponderhit(); cout << "bestmove " << bookMove << endl; - return !QuitRequest; + return; } } @@ -432,16 +437,9 @@ bool think(Position& pos, const SearchLimits& limits, Move searchMoves[]) { else Threads.set_timer(100); - // Start async mode to catch UCI commands sent to us while searching, - // like "quit", "stop", etc. - Threads.start_listener(); - // We're ready to start thinking. Call the iterative deepening loop function Move ponderMove = MOVE_NONE; - Move bestMove = id_loop(pos, searchMoves, &ponderMove); - - // From now on any UCI command will be read in-sync with Threads.getline() - Threads.stop_listener(); + Move bestMove = id_loop(pos, &RootMoves[0], &ponderMove); // Stop timer, no need to check for available time any more Threads.set_timer(0); @@ -465,10 +463,11 @@ bool think(Position& pos, const SearchLimits& limits, Move searchMoves[]) { pos.undo_move(bestMove); // Return from think() with unchanged position } - // If we are pondering or in infinite search, we shouldn't print the best move + // 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. - if (Limits.ponder || Limits.infinite) - wait_for_stop_or_ponderhit(); + 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; @@ -479,8 +478,6 @@ bool think(Position& pos, const SearchLimits& limits, Move searchMoves[]) { cout << " ponder " << ponderMove; cout << endl; - - return !QuitRequest; } @@ -490,7 +487,7 @@ 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 searchMoves[], Move* ponderMove) { + Move id_loop(Position& pos, Move rootMoves[], Move* ponderMove) { SearchStack ss[PLY_MAX_PLUS_2]; Value bestValues[PLY_MAX_PLUS_2]; @@ -510,7 +507,7 @@ namespace { ss->currentMove = MOVE_NULL; // Hack to skip update gains // Moves to search are verified and copied - Rml.init(pos, searchMoves); + Rml.init(pos, rootMoves); // Handle special case of searching on a mate/stalemate position if (!Rml.size()) @@ -522,7 +519,7 @@ namespace { } // Iterative deepening loop until requested to stop or target depth reached - while (!StopRequest && ++depth <= PLY_MAX && (!Limits.maxDepth || depth <= Limits.maxDepth)) + while (!Signals.stop && ++depth <= PLY_MAX && (!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++) @@ -581,7 +578,7 @@ namespace { // 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 (StopRequest) + if (Signals.stop) break; // Send full PV info to GUI if we are going to leave the loop or @@ -616,8 +613,8 @@ namespace { } else if (bestValue <= alpha) { - AspirationFailLow = true; - StopOnPonderhit = false; + Signals.failedLowAtRoot = true; + Signals.stopOnPonderhit = false; alpha = std::max(alpha - aspirationDelta, -VALUE_INFINITE); aspirationDelta += aspirationDelta / 2; @@ -648,9 +645,11 @@ namespace { if (depth > 2 && bestMoveChanges[depth]) bestMoveNeverChanged = false; - // Check for some early stop condition - if (!StopRequest && Limits.useTimeManagement()) + // Do we have time for the next iteration? Can we stop searching now? + if (!Signals.stop && !Signals.stopOnPonderhit && Limits.useTimeManagement()) { + bool stop = false; // Local variable instead of 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]); @@ -658,11 +657,11 @@ namespace { // 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) - StopRequest = true; + stop = true; // Stop search early if one move seems to be much better than others if ( depth >= 10 - && !StopRequest + && !stop && ( bestMoveNeverChanged || elapsed_search_time() > (TimeMgr.available_time() * 40) / 100)) { @@ -674,14 +673,17 @@ namespace { (ss+1)->excludedMove = MOVE_NONE; if (v < rBeta) - StopRequest = true; + stop = true; } - // If we are allowed to ponder do not stop the search now but keep pondering - if (StopRequest && Limits.ponder) + if (stop) { - StopRequest = false; - StopOnPonderhit = true; + // 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 + Signals.stopOnPonderhit = true; + else + Signals.stop = true; } } } @@ -729,7 +731,8 @@ namespace { ValueType vt; Value bestValue, value, oldAlpha; Value refinedValue, nullValue, futilityBase, futilityValue; - bool isPvMove, inCheck, singularExtensionNode, givesCheck, captureOrPromotion, dangerous; + bool isPvMove, inCheck, singularExtensionNode, givesCheck; + bool captureOrPromotion, dangerous, doFullDepthSearch; int moveCount = 0, playedMoveCount = 0; Thread& thread = Threads[pos.thread()]; SplitPoint* sp = NULL; @@ -760,7 +763,7 @@ namespace { } // Step 2. Check for aborted search and immediate draw - if (( StopRequest + if (( Signals.stop || pos.is_draw() || ss->ply > PLY_MAX) && !RootNode) return VALUE_DRAW; @@ -1019,7 +1022,7 @@ split_point_start: // At split points actual search starts from here if (RootNode) { // This is used by time management - FirstRootMove = (moveCount == 1); + Signals.firstRootMove = (moveCount == 1); // Save the current node count before the move is searched nodes = pos.nodes_searched(); @@ -1055,11 +1058,11 @@ split_point_start: // At split points actual search starts from here Value rBeta = ttValue - int(depth); ss->excludedMove = move; ss->skipNullMove = true; - Value v = search(pos, ss, rBeta - 1, rBeta, depth / 2); + value = search(pos, ss, rBeta - 1, rBeta, depth / 2); ss->skipNullMove = false; ss->excludedMove = MOVE_NONE; ss->bestMove = MOVE_NONE; - if (v < rBeta) + if (value < rBeta) ext = ONE_PLY; } } @@ -1133,51 +1136,44 @@ split_point_start: // At split points actual search starts from here // Step 14. Make the move pos.do_move(move, st, ci, givesCheck); - // Step extra. pv search (only in PV nodes) - // The first move in list is the expected PV - if (isPvMove) - value = newDepth < ONE_PLY ? -qsearch(pos, ss+1, -beta, -alpha, DEPTH_ZERO) - : - search(pos, ss+1, -beta, -alpha, newDepth); - else + // Step 15. Reduced depth search (LMR). If the move fails high will be + // re-searched at full depth. + if ( depth > 3 * ONE_PLY + && !isPvMove + && !captureOrPromotion + && !dangerous + && !is_castle(move) + && ss->killers[0] != move + && ss->killers[1] != move) { - // Step 15. Reduced depth search - // If the move fails high will be re-searched at full depth. - bool doFullDepthSearch = true; - - if ( depth > 3 * ONE_PLY - && !captureOrPromotion - && !dangerous - && !is_castle(move) - && ss->killers[0] != move - && ss->killers[1] != move - && (ss->reduction = reduction(depth, moveCount)) != DEPTH_ZERO) - { - Depth d = newDepth - ss->reduction; - alpha = SpNode ? sp->alpha : alpha; + ss->reduction = reduction(depth, moveCount); + Depth d = newDepth - ss->reduction; + 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 = d < ONE_PLY ? -qsearch(pos, ss+1, -(alpha+1), -alpha, DEPTH_ZERO) + : - search(pos, ss+1, -(alpha+1), -alpha, d); - ss->reduction = DEPTH_ZERO; - doFullDepthSearch = (value > alpha); - } + doFullDepthSearch = (value > alpha && ss->reduction != DEPTH_ZERO); + ss->reduction = DEPTH_ZERO; + } + else + doFullDepthSearch = !isPvMove; - // Step 16. Full depth search - if (doFullDepthSearch) - { - alpha = SpNode ? sp->alpha : alpha; - value = newDepth < ONE_PLY ? -qsearch(pos, ss+1, -(alpha+1), -alpha, DEPTH_ZERO) - : - search(pos, ss+1, -(alpha+1), -alpha, newDepth); - - // Step extra. pv search (only in PV nodes) - // Search only for possible new PV nodes, if instead value >= beta then - // parent node fails low with value <= alpha and tries another move. - if (PvNode && value > alpha && (RootNode || value < beta)) - value = newDepth < ONE_PLY ? -qsearch(pos, ss+1, -beta, -alpha, DEPTH_ZERO) - : - search(pos, ss+1, -beta, -alpha, newDepth); - } + // Step 16. Full depth search, when LMR is skipped or fails high + if (doFullDepthSearch) + { + alpha = SpNode ? sp->alpha : alpha; + value = newDepth < ONE_PLY ? -qsearch(pos, ss+1, -(alpha+1), -alpha, DEPTH_ZERO) + : - search(pos, ss+1, -(alpha+1), -alpha, newDepth); } + // Only for PV nodes do a full PV search on the first move or after a fail + // high, in the latter case search only if value < beta, otherwise let the + // parent node to fail low with value <= alpha and to try another move. + if (PvNode && (isPvMove || (value > alpha && (RootNode || value < beta)))) + value = newDepth < ONE_PLY ? -qsearch(pos, ss+1, -beta, -alpha, DEPTH_ZERO) + : - search(pos, ss+1, -beta, -alpha, newDepth); + // Step 17. Undo move pos.undo_move(move); @@ -1195,7 +1191,7 @@ split_point_start: // At split points actual search starts from here // 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 && !StopRequest) + if (RootNode && !Signals.stop) { // Remember searched nodes counts for this move RootMove* rm = Rml.find(move); @@ -1246,7 +1242,7 @@ split_point_start: // At split points actual search starts from here && depth >= Threads.min_split_depth() && bestValue < beta && Threads.available_slave_exists(pos.thread()) - && !StopRequest + && !Signals.stop && !thread.cutoff_occurred()) bestValue = Threads.split(pos, ss, alpha, beta, bestValue, depth, threatMove, moveCount, &mp, NT); @@ -1264,7 +1260,7 @@ split_point_start: // At split points actual search starts from here // Step 21. Update tables // If the search is not aborted, update the transposition table, // history counters, and killer moves. - if (!SpNode && !StopRequest && !thread.cutoff_occurred()) + if (!SpNode && !Signals.stop && !thread.cutoff_occurred()) { move = bestValue <= oldAlpha ? MOVE_NONE : ss->bestMove; vt = bestValue <= oldAlpha ? VALUE_TYPE_UPPER @@ -1907,26 +1903,6 @@ split_point_start: // At split points actual search starts from here } - // wait_for_stop_or_ponderhit() is called when the maximum depth is reached - // while the program is pondering. The point is to work around a wrinkle in - // the UCI protocol: When pondering, the engine is not allowed to give a - // "bestmove" before the GUI sends it a "stop" or "ponderhit" command. - // We simply wait here until one of these commands (that raise StopRequest) is - // sent, and return, after which the bestmove and pondermove will be printed. - - void wait_for_stop_or_ponderhit() { - - string cmd; - StopOnPonderhit = true; - - while (!StopRequest) - { - Threads.getline(cmd); - do_uci_async_cmd(cmd); - } - } - - // When playing with strength handicap choose best move among the MultiPV set // using a statistical rule dependent on SkillLevel. Idea by Heinz van Saanen. @@ -1974,7 +1950,7 @@ split_point_start: // At split points actual search starts from here /// RootMove and RootMoveList method's definitions - void RootMoveList::init(Position& pos, Move searchMoves[]) { + void RootMoveList::init(Position& pos, Move rootMoves[]) { Move* sm; bestMoveChanges = 0; @@ -1983,11 +1959,11 @@ split_point_start: // At split points actual search starts from here // Generate all legal moves and add them to RootMoveList for (MoveList ml(pos); !ml.end(); ++ml) { - // If we have a searchMoves[] list then verify the move + // If we have a rootMoves[] list then verify the move // is in the list before to add it. - for (sm = searchMoves; *sm && *sm != ml.move(); sm++) {} + for (sm = rootMoves; *sm && *sm != ml.move(); sm++) {} - if (sm != searchMoves && *sm != ml.move()) + if (sm != rootMoves && *sm != ml.move()) continue; RootMove rm; @@ -2169,30 +2145,6 @@ void Thread::idle_loop(SplitPoint* sp) { } -// do_uci_async_cmd() is called by listener thread when in async mode and 'cmd' -// input line is received from the GUI. - -void do_uci_async_cmd(const std::string& cmd) { - - if (cmd == "quit") - QuitRequest = StopRequest = true; - - else if (cmd == "stop") - StopRequest = true; - - else if (cmd == "ponderhit") - { - // The opponent has played the expected move. GUI sends "ponderhit" if - // we were told to ponder on the same move the opponent has played. We - // should continue searching but switching from pondering to normal search. - Limits.ponder = false; - - if (StopOnPonderhit) - StopRequest = true; - } -} - - // do_timer_event() is called by the timer thread when the timer triggers void do_timer_event() { @@ -2200,8 +2152,8 @@ void do_timer_event() { static int lastInfoTime; int e = elapsed_search_time(); - // Print debug information every second - if (get_system_time() - lastInfoTime >= 1000) + // Print debug information every one second + if (!lastInfoTime || get_system_time() - lastInfoTime >= 1000) { lastInfoTime = get_system_time(); @@ -2213,8 +2165,8 @@ void do_timer_event() { if (Limits.ponder) return; - bool stillAtFirstMove = FirstRootMove - && !AspirationFailLow + bool stillAtFirstMove = Signals.firstRootMove + && !Signals.failedLowAtRoot && e > TimeMgr.available_time(); bool noMoreTime = e > TimeMgr.maximum_time() @@ -2223,5 +2175,5 @@ void do_timer_event() { if ( (Limits.useTimeManagement() && noMoreTime) || (Limits.maxTime && e >= Limits.maxTime) /* missing nodes limit */ ) // FIXME - StopRequest = true; + Signals.stop = true; }