X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=2c4d5ece2eb237f861890d7ac4add6c1c8c273ed;hp=660fb7ed4f045d85f886b10c3d8687be24fe2368;hb=a1b8c8109b464abd9d026b1ef740f1bace814b29;hpb=721d5576811e5b641f73c07bdeb122d114cae7ca diff --git a/src/search.cpp b/src/search.cpp index 660fb7ed..2c4d5ece 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -23,6 +23,7 @@ //// #include +#include #include #include #include @@ -100,7 +101,7 @@ namespace { // sorting the moves. A move m1 is considered to be better // than a move m2 if it has a higher score, or if the moves // have equal score but m1 has the higher node count. - bool RootMove::operator<(const RootMove& m) const { + bool operator<(const RootMove& m) const { return score != m.score ? score < m.score : theirBeta <= m.theirBeta; } @@ -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. @@ -190,13 +191,6 @@ 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 @@ -231,7 +225,7 @@ 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 +236,10 @@ 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; @@ -288,6 +286,7 @@ namespace { bool ok_to_do_nullmove(const Position& pos); bool ok_to_prune(const Position& pos, Move m, Move threat); bool ok_to_use_TT(const TTEntry* tte, Depth depth, Value beta, int ply); + 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); @@ -365,8 +364,20 @@ 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()) @@ -380,15 +391,6 @@ 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; @@ -456,51 +458,45 @@ 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) - { - MaxSearchTime = myTime / 30 + myIncrement; - AbsoluteMaxSearchTime = Max(myTime / 4, myIncrement - 100); - } - else // Blitz game without increment + if (!movesToGo) // Sudden death time control { - 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) @@ -569,6 +565,10 @@ void init_threads() { pthread_t pthread[1]; #endif + // Init our logarithmic lookup table + for (int 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; @@ -648,6 +648,8 @@ 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() { @@ -777,7 +779,7 @@ namespace { Problem = false; - if (!InfiniteSearch) + if (UseTimeManagement) { // Time to stop? bool stopSearch = false; @@ -831,9 +833,9 @@ 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 && (PonderSearch || InfiniteSearch)) wait_for_stop_or_ponderhit(); else // Print final search statistics @@ -881,7 +883,7 @@ 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 @@ -898,7 +900,7 @@ namespace { int64_t nodes; Move move; StateInfo st; - Depth ext, newDepth; + Depth depth, ext, newDepth; RootMoveNumber = i + 1; FailHigh = false; @@ -921,8 +923,9 @@ 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); @@ -949,18 +952,23 @@ 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); @@ -1087,7 +1095,6 @@ namespace { assert(threadID >= 0 && threadID < ActiveThreads); Move movesSearched[256]; - EvalInfo ei; StateInfo st; const TTEntry* tte; Move ttMove, move; @@ -1095,7 +1102,7 @@ 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); @@ -1108,12 +1115,9 @@ 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); @@ -1200,20 +1204,24 @@ 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 - && moveCount >= LMRPVMoves && !dangerous && !captureOrPromotion && !move_is_castle(move) && !move_is_killer(move, ss[ply])) { - ss[ply].reduction = OnePly; - value = -search(pos, ss, -alpha, newDepth-OnePly, ply+1, true, threadID); + double red = 0.5 + ln(moveCount) * ln(depth / 2) / 6.0; + if (red >= 1.0) + { + 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 - 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); @@ -1316,11 +1324,11 @@ 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); @@ -1333,12 +1341,9 @@ 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; @@ -1360,26 +1365,45 @@ namespace { return value_from_tt(tte->value(), ply); } - approximateEval = quick_evaluate(pos); 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; pos.do_null_move(st); // Null move dynamic reduction based on depth - int R = (depth >= 5 * OnePly ? 4 : 3); + 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); @@ -1414,13 +1438,14 @@ 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; @@ -1428,7 +1453,7 @@ 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]; @@ -1439,17 +1464,8 @@ 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 @@ -1460,8 +1476,8 @@ 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 @@ -1507,9 +1523,6 @@ namespace { continue; // Value based pruning - if (futilityValue == VALUE_NONE) - futilityValue = evaluate(pos, ei, threadID) + FutilityValueMargin; - futilityValueScaled = futilityValue - moveCount * IncrementalFutilityMargin; if (futilityValueScaled < beta) @@ -1525,20 +1538,25 @@ 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 - && moveCount >= LMRNonPVMoves && !dangerous && !captureOrPromotion && !move_is_castle(move) - && !move_is_killer(move, ss[ply])) + && !move_is_killer(move, ss[ply]) + /* && move != ttMove*/) { - ss[ply].reduction = OnePly; - value = -search(pos, ss, -(beta-1), newDepth-OnePly, ply+1, true, threadID); + double red = 0.5 + ln(moveCount) * ln(depth / 2) / 3.0; + if (red >= 1.0) + { + 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 - 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); @@ -1571,9 +1589,9 @@ 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, @@ -1587,12 +1605,13 @@ 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); @@ -1617,7 +1636,7 @@ 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; @@ -1631,42 +1650,32 @@ 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; @@ -1689,6 +1698,7 @@ namespace { MovePicker mp = MovePicker(pos, ttMove, 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. @@ -1697,11 +1707,12 @@ 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 @@ -1711,12 +1722,9 @@ 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) { @@ -1752,31 +1760,31 @@ 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; } @@ -1798,14 +1806,13 @@ 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) @@ -1839,12 +1846,6 @@ 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) @@ -1866,19 +1867,23 @@ 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 - && moveCount >= LMRNonPVMoves && !captureOrPromotion && !move_is_castle(move) && !move_is_killer(move, ss[sp->ply])) { - ss[sp->ply].reduction = OnePly; - value = -search(pos, ss, -(sp->beta-1), newDepth - OnePly, sp->ply+1, true, threadID); + double red = 0.5 + ln(moveCount) * ln(sp->depth / 2) / 3.0; + if (red >= 1.0) + { + 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 - 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); @@ -1943,7 +1948,7 @@ 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 @@ -1972,27 +1977,33 @@ 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 - && moveCount >= LMRPVMoves && !captureOrPromotion && !move_is_castle(move) && !move_is_killer(move, ss[sp->ply])) { - ss[sp->ply].reduction = OnePly; - value = -search(pos, ss, -sp->alpha, newDepth - OnePly, sp->ply+1, true, threadID); + double red = 0.5 + ln(moveCount) * ln(sp->depth / 2) / 6.0; + if (red >= 1.0) + { + 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 - 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. @@ -2126,13 +2137,13 @@ namespace { // RootMoveList simple methods definitions - inline void RootMoveList::set_move_nodes(int moveNum, int64_t nodes) { + void RootMoveList::set_move_nodes(int moveNum, int64_t nodes) { moves[moveNum].nodes = nodes; moves[moveNum].cumulativeNodes += nodes; } - inline void RootMoveList::set_beta_counters(int moveNum, int64_t our, int64_t their) { + void RootMoveList::set_beta_counters(int moveNum, int64_t our, int64_t their) { moves[moveNum].ourBeta = our; moves[moveNum].theirBeta = their; @@ -2152,7 +2163,7 @@ namespace { // RootMoveList::sort() sorts the root move list at the beginning of a new // iteration. - inline void RootMoveList::sort() { + void RootMoveList::sort() { sort_multipv(count - 1); // Sort all items } @@ -2474,6 +2485,23 @@ namespace { } + // 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) { + + if (!tte) + return defaultEval; + + Value v = value_from_tt(tte->value(), ply); + + if ( (is_lower_bound(tte->type()) && v >= defaultEval) + || (is_upper_bound(tte->type()) && v < defaultEval)) + return v; + + return defaultEval; + } + // update_history() registers a good move that produced a beta-cutoff // in history and marks as failures all the other moves of that ply. @@ -2624,7 +2652,7 @@ 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; @@ -2654,7 +2682,7 @@ namespace { || stillAtFirstMove || noProblemFound; - if (Iteration >= 3 && !InfiniteSearch && (noMoreTime || StopOnPonderhit)) + if (Iteration >= 3 && UseTimeManagement && (noMoreTime || StopOnPonderhit)) AbortSearch = true; }