X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=a6e2c3410d504bf3d9f3de04abb0ba3249b59e65;hp=6250f02fa4254718935c4fe48f72da7f4f71ab74;hb=2f760cdf8dba05feb2c964b5f3b3339f0567a3c0;hpb=a88e762b4ea4a3696ecc0431237f54090a5aa1e2 diff --git a/src/search.cpp b/src/search.cpp index 6250f02f..a6e2c341 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 Marco Costalba + Copyright (C) 2008-2009 Marco Costalba Stockfish is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -72,7 +72,8 @@ namespace { // Apart for the first one that has its score, following moves // normally have score -VALUE_INFINITE, so are ordered according // to the number of beta cutoffs occurred under their subtree during - // the last iteration. + // the last iteration. The counters are per thread variables to avoid + // concurrent accessing under SMP case. struct BetaCounterType { @@ -80,8 +81,6 @@ namespace { void clear(); void add(Color us, Depth d, int threadID); void read(Color us, int64_t& our, int64_t& their); - - int64_t hits[THREAD_MAX][2]; }; @@ -129,17 +128,13 @@ namespace { }; - /// Constants and variables initialized from UCI options - - // Minimum number of full depth (i.e. non-reduced) moves at PV and non-PV - // nodes - int LMRPVMoves, LMRNonPVMoves; + /// Constants - // Depth limit for use of dynamic threat detection - Depth ThreatDepth; + // Search depth at iteration 1 + const Depth InitialDepth = OnePly /*+ OnePly/2*/; // Depth limit for selective search - const Depth SelectiveDepth = 7*OnePly; + const Depth SelectiveDepth = 7 * OnePly; // Use internal iterative deepening? const bool UseIIDAtPVNodes = true; @@ -175,25 +170,31 @@ namespace { const bool PruneDefendingMoves = false; const bool PruneBlockingMoves = false; - // Use futility pruning? - bool UseQSearchFutilityPruning, UseFutilityPruning; - // Margins for futility pruning in the quiescence search, and at frontier // and near frontier nodes const Value FutilityMarginQS = Value(0x80); - // Remaining depth: 1 ply 1.5 ply 2 ply 2.5 ply 3 ply 3.5 ply - const Value FutilityMargins[12] = { Value(0x100), Value(0x120), Value(0x200), Value(0x220), Value(0x250), Value(0x270), + // Remaining depth: 1 ply 1.5 ply 2 ply 2.5 ply 3 ply 3.5 ply + const Value FutilityMargins[12] = { Value(0x100), Value(0x120), Value(0x200), Value(0x220), Value(0x250), Value(0x270), // 4 ply 4.5 ply 5 ply 5.5 ply 6 ply 6.5 ply Value(0x2A0), Value(0x2C0), Value(0x340), Value(0x360), Value(0x3A0), Value(0x3C0) }; - // Razoring - const Depth RazorDepth = 4*OnePly; + // Razoring + const Depth RazorDepth = 4*OnePly; // Remaining depth: 1 ply 1.5 ply 2 ply 2.5 ply 3 ply 3.5 ply const Value RazorMargins[6] = { Value(0x180), Value(0x300), Value(0x300), Value(0x3C0), Value(0x3C0), Value(0x3C0) }; // Remaining depth: 1 ply 1.5 ply 2 ply 2.5 ply 3 ply 3.5 ply - const Value RazorApprMargins[6] = { Value(0x520), Value(0x300), Value(0x300), Value(0x300), Value(0x300), Value(0x300) }; + const Value RazorApprMargins[6] = { Value(0x520), Value(0x300), Value(0x300), Value(0x300), Value(0x300), Value(0x300) }; + + + /// Variables initialized from UCI options + + // Minimum number of full depth (i.e. non-reduced) moves at PV and non-PV nodes + int LMRPVMoves, LMRNonPVMoves; // heavy SMP read access for the latter + + // Depth limit for use of dynamic threat detection + Depth ThreatDepth; // heavy SMP read access // Last seconds noise filtering (LSN) bool UseLSNFiltering; @@ -202,21 +203,15 @@ namespace { Value LSNValue; // Extensions. Array index 0 is used at non-PV nodes, index 1 at PV nodes. + // There is heavy SMP read access on these arrays Depth CheckExtension[2], SingleReplyExtension[2], PawnPushTo7thExtension[2]; Depth PassedPawnExtension[2], PawnEndgameExtension[2], MateThreatExtension[2]; - // Search depth at iteration 1 - const Depth InitialDepth = OnePly /*+ OnePly/2*/; - - // Node counters - int NodesSincePoll; - int NodesBetweenPolls = 30000; - // Iteration counters int Iteration; - BetaCounterType BetaCounter; + BetaCounterType BetaCounter; // has per-thread internal data - // Scores and number of times the best move changed for each iteration: + // Scores and number of times the best move changed for each iteration IterationInfoType IterationInfo[PLY_MAX_PLUS_2]; int BestMoveChangesByIteration[PLY_MAX_PLUS_2]; @@ -232,7 +227,7 @@ namespace { bool InfiniteSearch; bool PonderSearch; bool StopOnPonderhit; - bool AbortSearch; + bool AbortSearch; // heavy SMP read access bool Quit; bool FailHigh; bool FailLow; @@ -264,6 +259,11 @@ namespace { HANDLE SitIdleEvent[THREAD_MAX]; #endif + // Node counters, used only by thread[0] but try to keep in different + // cache lines (64 bytes each) from the heavy SMP read accessed variables. + int NodesSincePoll; + int NodesBetweenPolls = 30000; + /// Functions @@ -282,10 +282,10 @@ namespace { bool move_is_killer(Move m, const SearchStack& ss); Depth extension(const Position &pos, Move m, bool pvNode, bool capture, bool check, bool singleReply, bool mateThreat, bool* dangerous); bool ok_to_do_nullmove(const Position &pos); - bool ok_to_prune(const Position &pos, Move m, Move threat, Depth d); + bool ok_to_prune(const Position &pos, Move m, Move threat, Depth d, const History& H); bool ok_to_use_TT(const TTEntry* tte, Depth depth, Value beta, int ply); bool ok_to_history(const Position &pos, Move m); - void update_history(const Position& pos, Move m, Depth depth, Move movesSearched[], int moveCount); + void update_history(const Position& pos, Move m, Depth depth, History& H, Move movesSearched[], int moveCount); void update_killers(Move m, SearchStack& ss); bool fail_high_ply_1(); @@ -331,11 +331,6 @@ int ActiveThreads = 1; // but it could turn out to be useful for debugging. Lock IOLock; -History H; // Should be made local? - -// The empty search stack -SearchStack EmptySearchStack; - // SearchStack::init() initializes a search stack. Used at the beginning of a // new search from the root. @@ -438,9 +433,6 @@ bool think(const Position &pos, bool infinite, bool ponder, int side_to_move, if (UseLogFile) LogFile.open(get_option_value_string("Search Log Filename").c_str(), std::ios::out | std::ios::app); - UseQSearchFutilityPruning = get_option_value_bool("Futility Pruning (Quiescence Search)"); - UseFutilityPruning = get_option_value_bool("Futility Pruning (Main Search)"); - UseLSNFiltering = get_option_value_bool("LSN filtering"); LSNTime = get_option_value_int("LSN Time Margin (sec)") * 1000; LSNValue = value_from_centipawns(get_option_value_int("LSN Value Margin")); @@ -598,10 +590,6 @@ void init_threads() { // Wait until the thread has finished launching: while (!Threads[i].running); } - - // Init also the empty search stack - EmptySearchStack.init(0); - EmptySearchStack.initKillers(); } @@ -652,7 +640,9 @@ namespace { // Initialize TT.new_search(); - H.clear(); + for (int i = 0; i < THREAD_MAX; i++) + Threads[i].H.clear(); + for (int i = 0; i < 3; i++) { ss[i].init(i); @@ -890,6 +880,10 @@ namespace { if (i < MultiPV) { + // Aspiration window is disabled in multi-pv case + if (MultiPV > 1) + alpha = -VALUE_INFINITE; + value = -search_pv(pos, ss, -beta, -alpha, newDepth, 1, 0); // If the value has dropped a lot compared to the last iteration, // set the boolean variable Problem to true. This variable is used @@ -1060,7 +1054,7 @@ namespace { // Initialize a MovePicker object for the current position, and prepare // to search all moves - MovePicker mp = MovePicker(pos, true, ttMove, ss[ply], depth); + MovePicker mp = MovePicker(pos, true, ttMove, depth, Threads[threadID].H, &ss[ply]); Move move, movesSearched[256]; int moveCount = 0; @@ -1189,7 +1183,7 @@ namespace { Move m = ss[ply].pv[ply]; if (ok_to_history(pos, m)) // Only non capture moves are considered { - update_history(pos, m, depth, movesSearched, moveCount); + update_history(pos, m, depth, Threads[threadID].H, movesSearched, moveCount); update_killers(m, ss[ply]); } TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, depth, m); @@ -1321,15 +1315,14 @@ namespace { // Initialize a MovePicker object for the current position, and prepare // to search all moves: - MovePicker mp = MovePicker(pos, false, ttMove, ss[ply], depth); + MovePicker mp = MovePicker(pos, false, ttMove, depth, Threads[threadID].H, &ss[ply]); Move move, movesSearched[256]; int moveCount = 0; Value value, bestValue = -VALUE_INFINITE; Bitboard dcCandidates = mp.discovered_check_candidates(); Value futilityValue = VALUE_NONE; - bool useFutilityPruning = UseFutilityPruning - && depth < SelectiveDepth + bool useFutilityPruning = depth < SelectiveDepth && !isCheck; // Loop through all legal moves until no moves remain or a beta cutoff @@ -1359,7 +1352,7 @@ namespace { { // History pruning. See ok_to_prune() definition if ( moveCount >= 2 + int(depth) - && ok_to_prune(pos, move, ss[ply].threatMove, depth)) + && ok_to_prune(pos, move, ss[ply].threatMove, depth, Threads[threadID].H)) continue; // Value based pruning @@ -1449,7 +1442,7 @@ namespace { Move m = ss[ply].pv[ply]; if (ok_to_history(pos, m)) // Only non capture moves are considered { - update_history(pos, m, depth, movesSearched, moveCount); + update_history(pos, m, depth, Threads[threadID].H, movesSearched, moveCount); update_killers(m, ss[ply]); } TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, depth, m); @@ -1542,7 +1535,7 @@ namespace { // Initialize a MovePicker object for the current position, and prepare // to search the moves. Because the depth is <= 0 here, only captures, // queen promotions and checks (only if depth == 0) will be generated. - MovePicker mp = MovePicker(pos, pvNode, ttMove, EmptySearchStack, depth); + MovePicker mp = MovePicker(pos, pvNode, ttMove, depth, Threads[threadID].H); Move move; int moveCount = 0; Bitboard dcCandidates = mp.discovered_check_candidates(); @@ -1560,8 +1553,7 @@ namespace { ss[ply].currentMove = move; // Futility pruning - if ( UseQSearchFutilityPruning - && enoughMaterial + if ( enoughMaterial && !isCheck && !pvNode && !move_promotion(move) @@ -1655,8 +1647,7 @@ namespace { Value value; Move move; bool isCheck = pos.is_check(); - bool useFutilityPruning = UseFutilityPruning - && sp->depth < SelectiveDepth + bool useFutilityPruning = sp->depth < SelectiveDepth && !isCheck; while ( sp->bestValue < sp->beta @@ -1685,7 +1676,7 @@ namespace { && !moveIsCapture && !move_promotion(move) && moveCount >= 2 + int(sp->depth) - && ok_to_prune(pos, move, ss[sp->ply].threatMove, sp->depth)) + && ok_to_prune(pos, move, ss[sp->ply].threatMove, sp->depth, Threads[threadID].H)) continue; // Make and search the move. @@ -1890,13 +1881,13 @@ namespace { void BetaCounterType::clear() { for (int i = 0; i < THREAD_MAX; i++) - hits[i][WHITE] = hits[i][BLACK] = 0ULL; + Threads[i].betaCutOffs[WHITE] = Threads[i].betaCutOffs[BLACK] = 0ULL; } void BetaCounterType::add(Color us, Depth d, int threadID) { // Weighted count based on depth - hits[threadID][us] += int(d); + Threads[threadID].betaCutOffs[us] += unsigned(d); } void BetaCounterType::read(Color us, int64_t& our, int64_t& their) { @@ -1904,8 +1895,8 @@ namespace { our = their = 0UL; for (int i = 0; i < THREAD_MAX; i++) { - our += hits[i][us]; - their += hits[i][opposite_color(us)]; + our += Threads[i].betaCutOffs[us]; + their += Threads[i].betaCutOffs[opposite_color(us)]; } } @@ -2293,7 +2284,7 @@ namespace { // non-tactical moves late in the move list close to the leaves are // candidates for pruning. - bool ok_to_prune(const Position &pos, Move m, Move threat, Depth d) { + bool ok_to_prune(const Position &pos, Move m, Move threat, Depth d, const History& H) { Square mfrom, mto, tfrom, tto; assert(move_is_ok(m)); @@ -2328,7 +2319,7 @@ namespace { return false; // Case 4: Don't prune moves with good history. - if (!H.ok_to_prune(pos.piece_on(move_from(m)), m, d)) + if (!H.ok_to_prune(pos.piece_on(mfrom), mto, d)) return false; // Case 5: If the moving piece in the threatened move is a slider, don't @@ -2372,16 +2363,16 @@ namespace { // update_history() registers a good move that produced a beta-cutoff // in history and marks as failures all the other moves of that ply. - void update_history(const Position& pos, Move m, Depth depth, + void update_history(const Position& pos, Move m, Depth depth, History& H, Move movesSearched[], int moveCount) { - H.success(pos.piece_on(move_from(m)), m, depth); + H.success(pos.piece_on(move_from(m)), move_to(m), depth); for (int i = 0; i < moveCount - 1; i++) { assert(m != movesSearched[i]); if (ok_to_history(pos, movesSearched[i])) - H.failure(pos.piece_on(move_from(movesSearched[i])), movesSearched[i]); + H.failure(pos.piece_on(move_from(movesSearched[i])), move_to(movesSearched[i])); } }