X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=f205774124063dca9e3fed76471d2e0083d89115;hp=18b972f27b4aba6348983f6894777329d117c5e9;hb=56e09b4cc82c1cda42815482967670499fc64b61;hpb=c99d963fa54ad1af375c796632ada34bd0cf2a29 diff --git a/src/search.cpp b/src/search.cpp index 18b972f2..f2057741 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -23,6 +23,7 @@ //// #include +#include #include #include #include @@ -172,9 +173,9 @@ namespace { // best move from the previous iteration, Problem is set back to false. const Value NoProblemMargin = Value(0x14); - // Null move margin. A null move search will not be done if the approximate + // Null move margin. A null move search will not be done if the static // evaluation of the position is more than NullMoveMargin below beta. - const Value NullMoveMargin = Value(0x300); + const Value NullMoveMargin = Value(0x200); // If the TT move is at least SingleReplyMargin better then the // remaining ones we will extend it. @@ -190,18 +191,8 @@ namespace { // Depth limit for 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) }; - - /// Variables initialized by UCI options - // Minimum number of full depth (i.e. non-reduced) moves at PV and non-PV nodes - int LMRPVMoves, LMRNonPVMoves; - // Depth limit for use of dynamic threat detection Depth ThreatDepth; @@ -231,7 +222,7 @@ namespace { int SearchStartTime; int MaxNodes, MaxDepth; int MaxSearchTime, AbsoluteMaxSearchTime, ExtraSearchTime, ExactMaxTime; - bool InfiniteSearch, PonderSearch, StopOnPonderhit; + bool UseTimeManagement, InfiniteSearch, PonderSearch, StopOnPonderhit; bool AbortSearch, Quit; bool FailHigh, FailLow, Problem; @@ -242,6 +233,10 @@ namespace { bool UseLogFile; std::ofstream LogFile; + // Natural logarithmic lookup table and its getter function + double lnArray[512]; + inline double ln(int i) { return lnArray[i]; } + // MP related variables int ActiveThreads = 1; Depth MinimumSplitDepth; @@ -326,13 +321,6 @@ namespace { //// Functions //// -//FIXME: HACK -static double lnArray[512]; - -inline double ln(int i) -{ - return lnArray[i]; -} /// 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. @@ -373,8 +361,20 @@ bool think(const Position& pos, bool infinite, bool ponder, int side_to_move, int time[], int increment[], int movesToGo, int maxDepth, int maxNodes, int maxTime, Move searchMoves[]) { - // Look for a book move - if (!infinite && !ponder && get_option_value_bool("OwnBook")) + // Initialize global search variables + Idle = StopOnPonderhit = AbortSearch = Quit = false; + FailHigh = FailLow = Problem = false; + NodesSincePoll = 0; + SearchStartTime = get_system_time(); + ExactMaxTime = maxTime; + MaxDepth = maxDepth; + MaxNodes = maxNodes; + InfiniteSearch = infinite; + PonderSearch = ponder; + UseTimeManagement = !ExactMaxTime && !MaxDepth && !MaxNodes && !InfiniteSearch; + + // Look for a book move, only during games, not tests + if (UseTimeManagement && !ponder && get_option_value_bool("OwnBook")) { Move bookMove; if (get_option_value_string("Book File") != OpeningBook.file_name()) @@ -388,15 +388,6 @@ bool think(const Position& pos, bool infinite, bool ponder, int side_to_move, } } - // Initialize global search variables - Idle = StopOnPonderhit = AbortSearch = Quit = false; - FailHigh = FailLow = Problem = false; - SearchStartTime = get_system_time(); - ExactMaxTime = maxTime; - NodesSincePoll = 0; - InfiniteSearch = infinite; - PonderSearch = ponder; - for (int i = 0; i < THREAD_MAX; i++) { Threads[i].nodes = 0ULL; @@ -432,8 +423,6 @@ bool think(const Position& pos, bool infinite, bool ponder, int side_to_move, MateThreatExtension[1] = Depth(get_option_value_int("Mate Threat Extension (PV nodes)")); MateThreatExtension[0] = Depth(get_option_value_int("Mate Threat Extension (non-PV nodes)")); - LMRPVMoves = get_option_value_int("Full Depth Moves (PV nodes)") + 1; - LMRNonPVMoves = get_option_value_int("Full Depth Moves (non-PV nodes)") + 1; ThreatDepth = get_option_value_int("Threat Depth") * OnePly; Chess960 = get_option_value_bool("UCI_Chess960"); @@ -453,6 +442,10 @@ bool think(const Position& pos, bool infinite, bool ponder, int side_to_move, { ActiveThreads = newActiveThreads; init_eval(ActiveThreads); + // HACK: init_eval() destroys the static castleRightsMask[] array in the + // Position class. The below line repairs the damage. + Position p(pos.to_fen()); + assert(pos.is_ok()); } // Wake up sleeping threads @@ -464,51 +457,45 @@ bool think(const Position& pos, bool infinite, bool ponder, int side_to_move, // Set thinking time int myTime = time[side_to_move]; int myIncrement = increment[side_to_move]; - - if (!movesToGo) // Sudden death time control + if (UseTimeManagement) { - if (myIncrement) + if (!movesToGo) // Sudden death time control { - MaxSearchTime = myTime / 30 + myIncrement; - AbsoluteMaxSearchTime = Max(myTime / 4, myIncrement - 100); - } - else // Blitz game without increment - { - MaxSearchTime = myTime / 30; - AbsoluteMaxSearchTime = myTime / 8; + if (myIncrement) + { + MaxSearchTime = myTime / 30 + myIncrement; + AbsoluteMaxSearchTime = Max(myTime / 4, myIncrement - 100); + } + else // Blitz game without increment + { + MaxSearchTime = myTime / 30; + AbsoluteMaxSearchTime = myTime / 8; + } } - } - else // (x moves) / (y minutes) - { - if (movesToGo == 1) + else // (x moves) / (y minutes) { - MaxSearchTime = myTime / 2; - AbsoluteMaxSearchTime = (myTime > 3000)? (myTime - 500) : ((myTime * 3) / 4); + if (movesToGo == 1) + { + MaxSearchTime = myTime / 2; + AbsoluteMaxSearchTime = (myTime > 3000)? (myTime - 500) : ((myTime * 3) / 4); + } + else + { + MaxSearchTime = myTime / Min(movesToGo, 20); + AbsoluteMaxSearchTime = Min((4 * myTime) / movesToGo, myTime / 3); + } } - else + + if (PonderingEnabled) { - MaxSearchTime = myTime / Min(movesToGo, 20); - AbsoluteMaxSearchTime = Min((4 * myTime) / movesToGo, myTime / 3); + MaxSearchTime += MaxSearchTime / 4; + MaxSearchTime = Min(MaxSearchTime, AbsoluteMaxSearchTime); } } - if (PonderingEnabled) - { - MaxSearchTime += MaxSearchTime / 4; - MaxSearchTime = Min(MaxSearchTime, AbsoluteMaxSearchTime); - } - - // Fixed depth or fixed number of nodes? - MaxDepth = maxDepth; - if (MaxDepth) - InfiniteSearch = true; // HACK - - MaxNodes = maxNodes; + // Set best NodesBetweenPolls interval if (MaxNodes) - { NodesBetweenPolls = Min(MaxNodes, 30000); - InfiniteSearch = true; // HACK - } else if (myTime && myTime < 1000) NodesBetweenPolls = 1000; else if (myTime && myTime < 5000) @@ -569,20 +556,19 @@ bool think(const Position& pos, bool infinite, bool ponder, int side_to_move, /// and initializes the split point stack and the global locks and condition /// objects. -#include //FIXME: HACK - void init_threads() { - // FIXME: HACK!! - for (int i = 0; i < 512; i++) - lnArray[i] = log(double(i)); - volatile int i; + bool ok; #if !defined(_MSC_VER) pthread_t pthread[1]; #endif + // Init our logarithmic lookup table + for (i = 0; i < 512; i++) + lnArray[i] = log(double(i)); // log() returns base-e logarithm + for (i = 0; i < THREAD_MAX; i++) Threads[i].activeSplitPoints = 0; @@ -613,12 +599,18 @@ void init_threads() { for (i = 1; i < THREAD_MAX; i++) { #if !defined(_MSC_VER) - pthread_create(pthread, NULL, init_thread, (void*)(&i)); + ok = (pthread_create(pthread, NULL, init_thread, (void*)(&i)) == 0); #else DWORD iID[1]; - CreateThread(NULL, 0, init_thread, (LPVOID)(&i), 0, iID); + ok = (CreateThread(NULL, 0, init_thread, (LPVOID)(&i), 0, iID) != NULL); #endif + if (!ok) + { + cout << "Failed to create thread number " << i << endl; + Application::exit_with_failure(); + } + // Wait until the thread has finished launching while (!Threads[i].running); } @@ -662,6 +654,8 @@ void SearchStack::init(int ply) { pv[ply] = pv[ply + 1] = MOVE_NONE; currentMove = threatMove = MOVE_NONE; reduction = Depth(0); + eval = VALUE_NONE; + evalInfo = NULL; } void SearchStack::initKillers() { @@ -791,7 +785,7 @@ namespace { Problem = false; - if (!InfiniteSearch) + if (UseTimeManagement) { // Time to stop? bool stopSearch = false; @@ -845,9 +839,9 @@ namespace { rml.sort(); - // If we are pondering, we shouldn't print the best move before we - // are told to do so - if (PonderSearch) + // If we are pondering or in infinite search, we shouldn't print the + // best move before we are told to do so. + if (!AbortSearch && !ExactMaxTime && (PonderSearch || InfiniteSearch)) wait_for_stop_or_ponderhit(); else // Print final search statistics @@ -895,7 +889,7 @@ namespace { Value root_search(Position& pos, SearchStack ss[], RootMoveList& rml, Value alpha, Value beta) { Value oldAlpha = alpha; - Value value; + Value value = -VALUE_INFINITE; CheckInfo ci(pos); // Loop through all the moves in the root move list @@ -912,7 +906,7 @@ namespace { int64_t nodes; Move move; StateInfo st; - Depth ext, newDepth; + Depth depth, ext, newDepth; RootMoveNumber = i + 1; FailHigh = false; @@ -935,8 +929,9 @@ namespace { bool moveIsCheck = pos.move_is_check(move); bool captureOrPromotion = pos.move_is_capture_or_promotion(move); bool dangerous; + depth = (Iteration - 2) * OnePly + InitialDepth; ext = extension(pos, move, true, captureOrPromotion, moveIsCheck, false, false, &dangerous); - newDepth = (Iteration - 2) * OnePly + ext + InitialDepth; + newDepth = depth + ext; // Make the move, and search it pos.do_move(move, st, ci, moveIsCheck); @@ -963,18 +958,23 @@ namespace { { // Try to reduce non-pv search depth by one ply if move seems not problematic, // if the move fails high will be re-searched at full depth. - if ( newDepth >= 3*OnePly - && i >= MultiPV + LMRPVMoves + bool doFullDepthSearch = true; + + if ( depth >= 3*OnePly // FIXME was newDepth && !dangerous && !captureOrPromotion && !move_is_castle(move)) { - ss[0].reduction = OnePly; - value = -search(pos, ss, -alpha, newDepth-OnePly, 1, true, 0); - } else - value = alpha + 1; // Just to trigger next condition + double red = 0.5 + ln(RootMoveNumber - MultiPV + 1) * ln(depth / 2) / 6.0; + if (red >= 1.0) + { + ss[0].reduction = Depth(int(floor(red * int(OnePly)))); + value = -search(pos, ss, -alpha, newDepth-ss[0].reduction, 1, true, 0); + doFullDepthSearch = (value > alpha); + } + } - if (value > alpha) + if (doFullDepthSearch) { value = -search(pos, ss, -alpha, newDepth, 1, true, 0); @@ -1101,7 +1101,6 @@ namespace { assert(threadID >= 0 && threadID < ActiveThreads); Move movesSearched[256]; - EvalInfo ei; StateInfo st; const TTEntry* tte; Move ttMove, move; @@ -1109,7 +1108,7 @@ namespace { Value oldAlpha, value; bool isCheck, mateThreat, singleEvasion, moveIsCheck, captureOrPromotion, dangerous; int moveCount = 0; - Value bestValue = -VALUE_INFINITE; + Value bestValue = value = -VALUE_INFINITE; if (depth < OnePly) return qsearch(pos, ss, alpha, beta, Depth(0), ply, threadID); @@ -1122,12 +1121,9 @@ namespace { if (AbortSearch || thread_should_stop(threadID)) return Value(0); - if (pos.is_draw()) + if (pos.is_draw() || ply >= PLY_MAX - 1) return VALUE_DRAW; - if (ply >= PLY_MAX - 1) - return pos.is_check() ? quick_evaluate(pos) : evaluate(pos, ei, threadID); - // Mate distance pruning oldAlpha = alpha; alpha = Max(value_mated_in(ply), alpha); @@ -1214,25 +1210,24 @@ namespace { { // Try to reduce non-pv search depth by one ply if move seems not problematic, // if the move fails high will be re-searched at full depth. + bool doFullDepthSearch = true; + if ( depth >= 3*OnePly && !dangerous && !captureOrPromotion && !move_is_castle(move) && !move_is_killer(move, ss[ply])) { - double red = ln(moveCount) * ln(depth / 2) / 3.0; + double red = 0.5 + ln(moveCount) * ln(depth / 2) / 6.0; if (red >= 1.0) { - ss[ply].reduction = Depth(floor(red * int(OnePly))); + ss[ply].reduction = Depth(int(floor(red * int(OnePly)))); value = -search(pos, ss, -alpha, newDepth-ss[ply].reduction, ply+1, true, threadID); + doFullDepthSearch = (value > alpha); } - else - value = alpha + 1; // Just to trigger next condition } - else - value = alpha + 1; // Just to trigger next condition - if (value > alpha) // Go with full depth non-pv search + if (doFullDepthSearch) // Go with full depth non-pv search { ss[ply].reduction = Depth(0); value = -search(pos, ss, -alpha, newDepth, ply+1, true, threadID); @@ -1335,11 +1330,11 @@ namespace { const TTEntry* tte; Move ttMove, move; Depth ext, newDepth; - Value approximateEval, nullValue, value, futilityValue, futilityValueScaled; + Value bestValue, staticValue, nullValue, value, futilityValue, futilityValueScaled; bool isCheck, useFutilityPruning, singleEvasion, moveIsCheck, captureOrPromotion, dangerous; bool mateThreat = false; int moveCount = 0; - Value bestValue = -VALUE_INFINITE; + futilityValue = staticValue = bestValue = value = -VALUE_INFINITE; if (depth < OnePly) return qsearch(pos, ss, beta-1, beta, Depth(0), ply, threadID); @@ -1352,12 +1347,9 @@ namespace { if (AbortSearch || thread_should_stop(threadID)) return Value(0); - if (pos.is_draw()) + if (pos.is_draw() || ply >= PLY_MAX - 1) return VALUE_DRAW; - if (ply >= PLY_MAX - 1) - return pos.is_check() ? quick_evaluate(pos) : evaluate(pos, ei, threadID); - // Mate distance pruning if (value_mated_in(ply) >= beta) return beta; @@ -1379,16 +1371,35 @@ namespace { return value_from_tt(tte->value(), ply); } - approximateEval = refine_eval(tte, quick_evaluate(pos), ply); isCheck = pos.is_check(); + // Calculate depth dependant futility pruning parameters + const int FutilityMoveCountMargin = 3 + (1 << (3 * int(depth) / 8)); + const int FutilityValueMargin = 112 * bitScanReverse32(int(depth) * int(depth) / 2); + + // Evaluate the position statically + if (!isCheck) + { + if (tte && (tte->type() & VALUE_TYPE_EVAL)) + staticValue = value_from_tt(tte->value(), ply); + else + { + staticValue = evaluate(pos, ei, threadID); + ss[ply].evalInfo = &ei; + } + + ss[ply].eval = staticValue; + futilityValue = staticValue + FutilityValueMargin; + staticValue = refine_eval(tte, staticValue, ply); // Enhance accuracy with TT value if possible + } + // Null move search if ( allowNullmove && depth > OnePly && !isCheck && !value_is_mate(beta) && ok_to_do_nullmove(pos) - && approximateEval >= beta - NullMoveMargin) + && staticValue >= beta - NullMoveMargin) { ss[ply].currentMove = MOVE_NULL; @@ -1398,7 +1409,7 @@ namespace { int R = 3 + (depth >= 5 * OnePly ? depth / 8 : 0); // Null move dynamic reduction based on value - if (approximateEval - beta > PawnValueMidgame) + if (staticValue - beta > PawnValueMidgame) R++; nullValue = -search(pos, ss, -(beta-1), depth-R*OnePly, ply+1, false, threadID); @@ -1433,13 +1444,14 @@ namespace { } // Null move search not allowed, try razoring else if ( !value_is_mate(beta) + && !isCheck && depth < RazorDepth - && approximateEval < beta - RazorApprMargins[int(depth) - 2] + && staticValue < beta - (NullMoveMargin + 16 * depth) && ss[ply - 1].currentMove != MOVE_NULL && ttMove == MOVE_NONE && !pos.has_pawn_on_7th(pos.side_to_move())) { - Value rbeta = beta - RazorMargins[int(depth) - 2]; + Value rbeta = beta - (NullMoveMargin + 16 * depth); Value v = qsearch(pos, ss, rbeta-1, rbeta, Depth(0), ply, threadID); if (v < rbeta) return v; @@ -1447,7 +1459,7 @@ namespace { // Go with internal iterative deepening if we don't have a TT move if (UseIIDAtNonPVNodes && ttMove == MOVE_NONE && depth >= 8*OnePly && - !isCheck && evaluate(pos, ei, threadID) >= beta - IIDMargin) + !isCheck && ss[ply].eval >= beta - IIDMargin) { search(pos, ss, beta, Min(depth/2, depth-2*OnePly), ply, false, threadID); ttMove = ss[ply].pv[ply]; @@ -1458,17 +1470,8 @@ namespace { // to search all moves. MovePicker mp = MovePicker(pos, ttMove, depth, H, &ss[ply]); CheckInfo ci(pos); - futilityValue = VALUE_NONE; useFutilityPruning = depth < SelectiveDepth && !isCheck; - // Calculate depth dependant futility pruning parameters - const int FutilityMoveCountMargin = 3 + (1 << (3 * int(depth) / 8)); - const int FutilityValueMargin = 112 * bitScanReverse32(int(depth) * int(depth) / 2); - - // Avoid calling evaluate() if we already have the score in TT - if (tte && (tte->type() & VALUE_TYPE_EVAL)) - futilityValue = value_from_tt(tte->value(), ply) + FutilityValueMargin; - // Loop through all legal moves until no moves remain or a beta cutoff occurs while ( bestValue < beta && (move = mp.get_next_move()) != MOVE_NONE @@ -1479,8 +1482,8 @@ namespace { if (move == excludedMove) continue; - singleEvasion = (isCheck && mp.number_of_evasions() == 1); moveIsCheck = pos.move_is_check(move, ci); + singleEvasion = (isCheck && mp.number_of_evasions() == 1); captureOrPromotion = pos.move_is_capture_or_promotion(move); // Decide the new search depth @@ -1526,9 +1529,6 @@ namespace { continue; // Value based pruning - if (futilityValue == VALUE_NONE) - futilityValue = evaluate(pos, ei, threadID) + FutilityValueMargin; - futilityValueScaled = futilityValue - moveCount * IncrementalFutilityMargin; if (futilityValueScaled < beta) @@ -1544,6 +1544,8 @@ namespace { // Try to reduce non-pv search depth by one ply if move seems not problematic, // if the move fails high will be re-searched at full depth. + bool doFullDepthSearch = true; + if ( depth >= 3*OnePly && !dangerous && !captureOrPromotion @@ -1551,19 +1553,16 @@ namespace { && !move_is_killer(move, ss[ply]) /* && move != ttMove*/) { - double red = ln(moveCount) * ln(depth / 2) / 1.5; + double red = 0.5 + ln(moveCount) * ln(depth / 2) / 3.0; if (red >= 1.0) { - ss[ply].reduction = Depth(floor(red * int(OnePly))); + ss[ply].reduction = Depth(int(floor(red * int(OnePly)))); value = -search(pos, ss, -(beta-1), newDepth-ss[ply].reduction, ply+1, true, threadID); + doFullDepthSearch = (value >= beta); } - else - value = beta; // Just to trigger next condition } - else - value = beta; // Just to trigger next condition - if (value >= beta) // Go with full depth non-pv search + if (doFullDepthSearch) // Go with full depth non-pv search { ss[ply].reduction = Depth(0); value = -search(pos, ss, -(beta-1), newDepth, ply+1, true, threadID); @@ -1596,9 +1595,9 @@ namespace { break; } - // All legal moves have been searched. A special case: If there were + // All legal moves have been searched. A special case: If there were // no legal moves, it must be mate or stalemate. - if (moveCount == 0) + if (!moveCount) return excludedMove ? beta - 1 : (pos.is_check() ? value_mated_in(ply) : VALUE_DRAW); // If the search is not aborted, update the transposition table, @@ -1612,12 +1611,13 @@ namespace { { BetaCounter.add(pos.side_to_move(), depth, threadID); move = ss[ply].pv[ply]; + TT.store(posKey, value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, depth, move); if (!pos.move_is_capture_or_promotion(move)) { update_history(pos, move, depth, movesSearched, moveCount); update_killers(move, ss[ply]); } - TT.store(posKey, value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, depth, move); + } assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE); @@ -1642,7 +1642,7 @@ namespace { EvalInfo ei; StateInfo st; Move ttMove, move; - Value staticValue, bestValue, value, futilityValue; + Value staticValue, bestValue, value, futilityBase, futilityValue; bool isCheck, enoughMaterial, moveIsCheck; const TTEntry* tte = NULL; int moveCount = 0; @@ -1656,42 +1656,32 @@ namespace { if (AbortSearch || thread_should_stop(threadID)) return Value(0); - if (pos.is_draw()) + if (pos.is_draw() || ply >= PLY_MAX - 1) return VALUE_DRAW; - // Transposition table lookup, only when not in PV - if (!pvNode) + // Transposition table lookup. At PV nodes, we don't use the TT for + // pruning, but only for move ordering. + tte = TT.retrieve(pos.get_key()); + ttMove = (tte ? tte->move() : MOVE_NONE); + + if (!pvNode && tte && ok_to_use_TT(tte, depth, beta, ply)) { - tte = TT.retrieve(pos.get_key()); - if (tte && ok_to_use_TT(tte, depth, beta, ply)) - { - assert(tte->type() != VALUE_TYPE_EVAL); + assert(tte->type() != VALUE_TYPE_EVAL); - return value_from_tt(tte->value(), ply); - } + ss[ply].currentMove = ttMove; // Can be MOVE_NONE + return value_from_tt(tte->value(), ply); } - ttMove = (tte ? tte->move() : MOVE_NONE); isCheck = pos.is_check(); - ei.futilityMargin = Value(0); // Manually initialize futilityMargin // Evaluate the position statically if (isCheck) staticValue = -VALUE_INFINITE; - else if (tte && (tte->type() & VALUE_TYPE_EVAL)) - { - // Use the cached evaluation score if possible - assert(ei.futilityMargin == Value(0)); - staticValue = value_from_tt(tte->value(), ply); - } else staticValue = evaluate(pos, ei, threadID); - if (ply >= PLY_MAX - 1) - return pos.is_check() ? quick_evaluate(pos) : evaluate(pos, ei, threadID); - // Initialize "stand pat score", and return it immediately if it is // at least beta. bestValue = staticValue; @@ -1708,12 +1698,17 @@ namespace { if (bestValue > alpha) alpha = bestValue; + // If we are near beta then try to get a cutoff pushing checks a bit further + bool deepChecks = depth == -OnePly && staticValue >= beta - PawnValueMidgame / 8; + // 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, ttMove, depth, H); + // to search the moves. Because the depth is <= 0 here, only captures, + // queen promotions and checks (only if depth == 0 or depth == -OnePly + // and we are near beta) will be generated. + MovePicker mp = MovePicker(pos, ttMove, deepChecks ? Depth(0) : depth, H); CheckInfo ci(pos); enoughMaterial = pos.non_pawn_material(pos.side_to_move()) > RookValueMidgame; + futilityBase = staticValue + FutilityMarginQS + ei.futilityMargin; // Loop through the moves until no moves remain or a beta cutoff // occurs. @@ -1722,11 +1717,12 @@ namespace { { assert(move_is_ok(move)); + moveIsCheck = pos.move_is_check(move, ci); + + // Update current move moveCount++; ss[ply].currentMove = move; - moveIsCheck = pos.move_is_check(move, ci); - // Futility pruning if ( enoughMaterial && !isCheck @@ -1736,12 +1732,9 @@ namespace { && !move_is_promotion(move) && !pos.move_is_passed_pawn_push(move)) { - futilityValue = staticValue - + Max(pos.midgame_value_of_piece_on(move_to(move)), - pos.endgame_value_of_piece_on(move_to(move))) - + (move_is_ep(move) ? PawnValueEndgame : Value(0)) - + FutilityMarginQS - + ei.futilityMargin; + futilityValue = futilityBase + + pos.endgame_value_of_piece_on(move_to(move)) + + (move_is_ep(move) ? PawnValueEndgame : Value(0)); if (futilityValue < alpha) { @@ -1777,31 +1770,31 @@ namespace { } } - // All legal moves have been searched. A special case: If we're in check + // All legal moves have been searched. A special case: If we're in check // and no legal moves were found, it is checkmate. if (!moveCount && pos.is_check()) // Mate! return value_mated_in(ply); - assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE); - // Update transposition table - move = ss[ply].pv[ply]; - if (!pvNode) + Depth d = (depth == Depth(0) ? Depth(0) : Depth(-1)); + if (bestValue < beta) { - // If bestValue isn't changed it means it is still the static evaluation of - // the node, so keep this info to avoid a future costly evaluation() call. + // If bestValue isn't changed it means it is still the static evaluation + // of the node, so keep this info to avoid a future evaluation() call. ValueType type = (bestValue == staticValue && !ei.futilityMargin ? VALUE_TYPE_EV_UP : VALUE_TYPE_UPPER); - Depth d = (depth == Depth(0) ? Depth(0) : Depth(-1)); + TT.store(pos.get_key(), value_to_tt(bestValue, ply), type, d, MOVE_NONE); + } + else + { + move = ss[ply].pv[ply]; + TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, d, move); - if (bestValue < beta) - TT.store(pos.get_key(), value_to_tt(bestValue, ply), type, d, MOVE_NONE); - else - TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, d, move); + // Update killers only for good checking moves + if (!pos.move_is_capture_or_promotion(move)) + update_killers(move, ss[ply]); } - // Update killers only for good check moves - if (alpha >= beta && !pos.move_is_capture_or_promotion(move)) - update_killers(move, ss[ply]); + assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE); return bestValue; } @@ -1823,14 +1816,13 @@ namespace { Position pos = Position(sp->pos); CheckInfo ci(pos); SearchStack* ss = sp->sstack[threadID]; - Value value; + Value value = -VALUE_INFINITE; Move move; bool isCheck = pos.is_check(); bool useFutilityPruning = sp->depth < SelectiveDepth && !isCheck; const int FutilityMoveCountMargin = 3 + (1 << (3 * int(sp->depth) / 8)); - const int FutilityValueMargin = 112 * bitScanReverse32(int(sp->depth) * int(sp->depth) / 2); while ( sp->bestValue < sp->beta && !thread_should_stop(threadID) @@ -1864,12 +1856,6 @@ namespace { continue; // Value based pruning - if (sp->futilityValue == VALUE_NONE) - { - EvalInfo ei; - sp->futilityValue = evaluate(pos, ei, threadID) + FutilityValueMargin; - } - Value futilityValueScaled = sp->futilityValue - moveCount * IncrementalFutilityMargin; if (futilityValueScaled < sp->beta) @@ -1891,24 +1877,23 @@ namespace { // Try to reduce non-pv search depth by one ply if move seems not problematic, // if the move fails high will be re-searched at full depth. + bool doFullDepthSearch = true; + if ( !dangerous && !captureOrPromotion && !move_is_castle(move) && !move_is_killer(move, ss[sp->ply])) { - double red = ln(moveCount) * ln(sp->depth / 2) / 1.5; + double red = 0.5 + ln(moveCount) * ln(sp->depth / 2) / 3.0; if (red >= 1.0) { - ss[sp->ply].reduction = Depth(floor(red * int(OnePly))); + ss[sp->ply].reduction = Depth(int(floor(red * int(OnePly)))); value = -search(pos, ss, -(sp->beta-1), newDepth-ss[sp->ply].reduction, sp->ply+1, true, threadID); + doFullDepthSearch = (value >= sp->beta); } - else - value = sp->beta; // Just to trigger next condition } - else - value = sp->beta; // Just to trigger next condition - if (value >= sp->beta) // Go with full depth non-pv search + if (doFullDepthSearch) // Go with full depth non-pv search { ss[sp->ply].reduction = Depth(0); value = -search(pos, ss, -(sp->beta - 1), newDepth, sp->ply+1, true, threadID); @@ -1973,7 +1958,7 @@ namespace { Position pos = Position(sp->pos); CheckInfo ci(pos); SearchStack* ss = sp->sstack[threadID]; - Value value; + Value value = -VALUE_INFINITE; Move move; while ( sp->alpha < sp->beta @@ -2002,39 +1987,47 @@ namespace { // Try to reduce non-pv search depth by one ply if move seems not problematic, // if the move fails high will be re-searched at full depth. + bool doFullDepthSearch = true; + if ( !dangerous && !captureOrPromotion && !move_is_castle(move) && !move_is_killer(move, ss[sp->ply])) { - double red = ln(moveCount) * ln(sp->depth / 2) / 3.0; + double red = 0.5 + ln(moveCount) * ln(sp->depth / 2) / 6.0; if (red >= 1.0) { - ss[sp->ply].reduction = Depth(floor(red * int(OnePly))); - value = -search(pos, ss, -sp->alpha, newDepth-ss[sp->ply].reduction, sp->ply+1, true, threadID); + Value localAlpha = sp->alpha; + ss[sp->ply].reduction = Depth(int(floor(red * int(OnePly)))); + value = -search(pos, ss, -localAlpha, newDepth-ss[sp->ply].reduction, sp->ply+1, true, threadID); + doFullDepthSearch = (value > localAlpha); } - else - value = sp->alpha + 1; // Just to trigger next condition } - else - value = sp->alpha + 1; // Just to trigger next condition - if (value > sp->alpha) // Go with full depth non-pv search + if (doFullDepthSearch) // Go with full depth non-pv search { + Value localAlpha = sp->alpha; ss[sp->ply].reduction = Depth(0); - value = -search(pos, ss, -sp->alpha, newDepth, sp->ply+1, true, threadID); + value = -search(pos, ss, -localAlpha, newDepth, sp->ply+1, true, threadID); - if (value > sp->alpha && value < sp->beta) + if (value > localAlpha && value < sp->beta) { // When the search fails high at ply 1 while searching the first - // move at the root, set the flag failHighPly1. This is used for + // move at the root, set the flag failHighPly1. This is used for // time managment: We don't want to stop the search early in // such cases, because resolving the fail high at ply 1 could // result in a big drop in score at the root. if (sp->ply == 1 && RootMoveNumber == 1) Threads[threadID].failHighPly1 = true; - value = -search_pv(pos, ss, -sp->beta, -sp->alpha, newDepth, sp->ply+1, threadID); + // If another thread has failed high then sp->alpha has been increased + // to be higher or equal then beta, if so, avoid to start a PV search. + localAlpha = sp->alpha; + if (localAlpha < sp->beta) + value = -search_pv(pos, ss, -sp->beta, -localAlpha, newDepth, sp->ply+1, threadID); + else + assert(thread_should_stop(threadID)); + Threads[threadID].failHighPly1 = false; } } @@ -2052,11 +2045,7 @@ namespace { sp->bestValue = value; if (value > sp->alpha) { - sp->alpha = value; - sp_update_pv(sp->parentSstack, ss, sp->ply); - if (value == value_mate_in(sp->ply + 1)) - ss[sp->ply].mateKiller = move; - + // Ask threads to stop before to modify sp->alpha if (value >= sp->beta) { for (int i = 0; i < ActiveThreads; i++) @@ -2065,6 +2054,12 @@ namespace { sp->finished = true; } + + sp->alpha = value; + + sp_update_pv(sp->parentSstack, ss, sp->ply); + if (value == value_mate_in(sp->ply + 1)) + ss[sp->ply].mateKiller = move; } // If we are at ply 1, and we are searching the first root move at // ply 0, set the 'Problem' variable if the score has dropped a lot @@ -2676,7 +2671,7 @@ namespace { || stillAtFirstMove //FIXME: We are not checking any problem flags, BUG? || noProblemFound; - if ( (Iteration >= 3 && !InfiniteSearch && noMoreTime) + if ( (Iteration >= 3 && UseTimeManagement && noMoreTime) || (ExactMaxTime && t >= ExactMaxTime) || (Iteration >= 3 && MaxNodes && nodes_searched() >= MaxNodes)) AbortSearch = true; @@ -2706,7 +2701,7 @@ namespace { || stillAtFirstMove || noProblemFound; - if (Iteration >= 3 && !InfiniteSearch && (noMoreTime || StopOnPonderhit)) + if (Iteration >= 3 && UseTimeManagement && (noMoreTime || StopOnPonderhit)) AbortSearch = true; } @@ -2808,6 +2803,8 @@ namespace { // If this thread has been assigned work, launch a search if (Threads[threadID].workIsWaiting) { + assert(!Threads[threadID].idle); + Threads[threadID].workIsWaiting = false; if (Threads[threadID].splitPoint->pvNode) sp_search_pv(Threads[threadID].splitPoint, threadID); @@ -2989,15 +2986,15 @@ namespace { for (i = 0; i < ActiveThreads; i++) splitPoint->slaves[i] = 0; - // Copy the current search stack to the master thread - memcpy(splitPoint->sstack[master], sstck, (ply+1) * sizeof(SearchStack)); + // Copy the tail of current search stack to the master thread + memcpy(splitPoint->sstack[master] + ply - 1, sstck + ply - 1, 3 * sizeof(SearchStack)); Threads[master].splitPoint = splitPoint; // Make copies of the current position and search stack for each thread for (i = 0; i < ActiveThreads && splitPoint->cpus < MaxThreadsPerSplitPoint; i++) if (thread_is_available(i, master)) { - memcpy(splitPoint->sstack[i], sstck, (ply+1) * sizeof(SearchStack)); + memcpy(splitPoint->sstack[i] + ply - 1, sstck + ply - 1, 3 * sizeof(SearchStack)); Threads[i].splitPoint = splitPoint; splitPoint->slaves[i] = 1; splitPoint->cpus++;