X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=64863be166b07f84f53571c10ee79e392f3d210d;hp=5606847a8370be6ed954b770ad3516474a88370f;hb=2155fb78256204aae5aa80946dfe7d8d9c6e2397;hpb=02cd96e4c2e8a3da79512df4ea803687f9193071 diff --git a/src/search.cpp b/src/search.cpp index 5606847a..64863be1 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -23,6 +23,7 @@ //// #include +#include #include #include #include @@ -47,6 +48,26 @@ namespace { /// Types + // IterationInfoType stores search results for each iteration + // + // Because we use relatively small (dynamic) aspiration window, + // there happens many fail highs and fail lows in root. And + // because we don't do researches in those cases, "value" stored + // here is not necessarily exact. Instead in case of fail high/low + // we guess what the right value might be and store our guess + // as a "speculated value" and then move on. Speculated values are + // used just to calculate aspiration window width, so also if are + // not exact is not big a problem. + + struct IterationInfoType { + + IterationInfoType(Value v = Value(0), Value sv = Value(0)) + : value(v), speculatedValue(sv) {} + + Value value, speculatedValue; + }; + + // The BetaCounterType class is used to order moves at ply one. // Apart for the first one that has its score, following moves // normally have score -VALUE_INFINITE, so are ordered according @@ -108,26 +129,22 @@ namespace { }; - /// Constants and variables + /// 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 = 15; - int LMRNonPVMoves = 4; + // nodes + int LMRPVMoves, LMRNonPVMoves; - // Depth limit for use of dynamic threat detection: - Depth ThreatDepth = 5*OnePly; + // Depth limit for use of dynamic threat detection + Depth ThreatDepth; - // Depth limit for selective search: - Depth SelectiveDepth = 7*OnePly; + // Depth limit for selective search + const Depth SelectiveDepth = 7*OnePly; // Use internal iterative deepening? const bool UseIIDAtPVNodes = true; const bool UseIIDAtNonPVNodes = false; - // Use null move driven internal iterative deepening? - bool UseNullDrivenIID = false; - // Internal iterative deepening margin. At Non-PV moves, when // UseIIDAtNonPVNodes is true, we do an internal iterative deepening search // when the static evaluation is at most IIDMargin below beta. @@ -159,33 +176,34 @@ namespace { const bool PruneBlockingMoves = false; // Use futility pruning? - bool UseQSearchFutilityPruning = true; - bool UseFutilityPruning = true; + bool UseQSearchFutilityPruning, UseFutilityPruning; // Margins for futility pruning in the quiescence search, and at frontier // and near frontier nodes - Value FutilityMarginQS = Value(0x80); - Value FutilityMargins[6] = { Value(0x100), Value(0x200), Value(0x250), - Value(0x2A0), Value(0x340), Value(0x3A0) }; + const Value FutilityMarginQS = Value(0x80); - // Razoring - const bool RazorAtDepthOne = false; - Depth RazorDepth = 4*OnePly; - Value RazorMargin = Value(0x300); + // 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; + + // 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) }; // Last seconds noise filtering (LSN) - bool UseLSNFiltering = false; + bool UseLSNFiltering; bool looseOnTime = false; - int LSNTime = 4 * 1000; // In milliseconds - Value LSNValue = Value(0x200); + int LSNTime; // In milliseconds + Value LSNValue; - // Extensions. Array index 0 is used at non-PV nodes, index 1 at PV nodes. - Depth CheckExtension[2] = {OnePly, OnePly}; - Depth SingleReplyExtension[2] = {OnePly / 2, OnePly / 2}; - Depth PawnPushTo7thExtension[2] = {OnePly / 2, OnePly / 2}; - Depth PassedPawnExtension[2] = {Depth(0), Depth(0)}; - Depth PawnEndgameExtension[2] = {OnePly, OnePly}; - Depth MateThreatExtension[2] = {Depth(0), Depth(0)}; + // Extensions. Array index 0 is used at non-PV nodes, index 1 at PV nodes. + 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*/; @@ -196,21 +214,20 @@ namespace { // Iteration counters int Iteration; - bool LastIterations; BetaCounterType BetaCounter; // Scores and number of times the best move changed for each iteration: - Value ValueByIteration[PLY_MAX_PLUS_2]; + IterationInfoType IterationInfo[PLY_MAX_PLUS_2]; int BestMoveChangesByIteration[PLY_MAX_PLUS_2]; // MultiPV mode - int MultiPV = 1; + int MultiPV; // Time managment variables int SearchStartTime; int MaxNodes, MaxDepth; int MaxSearchTime, AbsoluteMaxSearchTime, ExtraSearchTime; - Move BestRootMove, PonderMove, EasyMove; + Move EasyMove; int RootMoveNumber; bool InfiniteSearch; bool PonderSearch; @@ -218,20 +235,21 @@ namespace { bool AbortSearch; bool Quit; bool FailHigh; + bool FailLow; bool Problem; bool PonderingEnabled; int ExactMaxTime; // Show current line? - bool ShowCurrentLine = false; + bool ShowCurrentLine; // Log file - bool UseLogFile = false; + bool UseLogFile; std::ofstream LogFile; // MP related variables - Depth MinimumSplitDepth = 4*OnePly; - int MaxThreadsPerSplitPoint = 4; + Depth MinimumSplitDepth; + int MaxThreadsPerSplitPoint; Thread Threads[THREAD_MAX]; Lock MPLock; bool AllThreadsShouldExit = false; @@ -250,16 +268,13 @@ namespace { /// Functions Value id_loop(const Position &pos, Move searchMoves[]); - Value root_search(Position &pos, SearchStack ss[], RootMoveList &rml); - Value search_pv(Position &pos, SearchStack ss[], Value alpha, Value beta, - Depth depth, int ply, int threadID); - Value search(Position &pos, SearchStack ss[], Value beta, - Depth depth, int ply, bool allowNullmove, int threadID); - Value qsearch(Position &pos, SearchStack ss[], Value alpha, Value beta, - Depth depth, int ply, int threadID); + Value root_search(Position &pos, SearchStack ss[], RootMoveList &rml, Value alpha, Value beta); + Value search_pv(Position &pos, SearchStack ss[], Value alpha, Value beta, Depth depth, int ply, int threadID); + Value search(Position &pos, SearchStack ss[], Value beta, Depth depth, int ply, bool allowNullmove, int threadID); + Value qsearch(Position &pos, SearchStack ss[], Value alpha, Value beta, Depth depth, int ply, int threadID); void sp_search(SplitPoint *sp, int threadID); void sp_search_pv(SplitPoint *sp, int threadID); - void init_node(const Position &pos, SearchStack ss[], int ply, int threadID); + void init_node(SearchStack ss[], int ply, int threadID); void update_pv(SearchStack ss[], int ply); void sp_update_pv(SearchStack *pss, SearchStack ss[], int ply); bool connected_moves(const Position &pos, Move m1, Move m2); @@ -306,7 +321,7 @@ namespace { //// // The main transposition table -TranspositionTable TT = TranspositionTable(TTDefaultSize); +TranspositionTable TT; // Number of active threads: @@ -329,7 +344,6 @@ void SearchStack::init(int ply) { pv[ply] = pv[ply + 1] = MOVE_NONE; currentMove = threatMove = MOVE_NONE; reduction = Depth(0); - currentMoveCaptureValue = Value(0); } void SearchStack::initKillers() { @@ -357,10 +371,8 @@ void think(const Position &pos, bool infinite, bool ponder, int side_to_move, { Move bookMove; if (get_option_value_string("Book File") != OpeningBook.file_name()) - { - OpeningBook.close(); OpeningBook.open("book.bin"); - } + bookMove = OpeningBook.get_move(pos); if (bookMove != MOVE_NONE) { @@ -372,8 +384,6 @@ void think(const Position &pos, bool infinite, bool ponder, int side_to_move, // Initialize global search variables Idle = false; SearchStartTime = get_system_time(); - BestRootMove = MOVE_NONE; - PonderMove = MOVE_NONE; EasyMove = MOVE_NONE; for (int i = 0; i < THREAD_MAX; i++) { @@ -387,6 +397,7 @@ void think(const Position &pos, bool infinite, bool ponder, int side_to_move, AbortSearch = false; Quit = false; FailHigh = false; + FailLow = false; Problem = false; ExactMaxTime = maxTime; @@ -419,7 +430,6 @@ void think(const Position &pos, bool infinite, bool ponder, int side_to_move, 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; - SelectiveDepth = get_option_value_int("Selective Plies") * OnePly; Chess960 = get_option_value_bool("UCI_Chess960"); ShowCurrentLine = get_option_value_bool("UCI_ShowCurrLine"); @@ -427,18 +437,9 @@ void 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); - UseNullDrivenIID = get_option_value_bool("Null driven IID"); UseQSearchFutilityPruning = get_option_value_bool("Futility Pruning (Quiescence Search)"); UseFutilityPruning = get_option_value_bool("Futility Pruning (Main Search)"); - FutilityMarginQS = value_from_centipawns(get_option_value_int("Futility Margin (Quiescence Search)")); - int fmScale = get_option_value_int("Futility Margin Scale Factor (Main Search)"); - for (int i = 0; i < 6; i++) - FutilityMargins[i] = (FutilityMargins[i] * fmScale) / 100; - - RazorDepth = (get_option_value_int("Maximum Razoring Depth") + 1) * OnePly; - RazorMargin = value_from_centipawns(get_option_value_int("Razoring Margin")); - 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")); @@ -542,7 +543,6 @@ void think(const Position &pos, bool infinite, bool ponder, int side_to_move, if (Quit) { - OpeningBook.close(); stop_threads(); quit_eval(); exit(0); @@ -662,15 +662,13 @@ namespace { ss[i].init(i); ss[i].initKillers(); } - ValueByIteration[0] = Value(0); - ValueByIteration[1] = rml.get_move_score(0); + IterationInfo[1] = IterationInfoType(rml.get_move_score(0), rml.get_move_score(0)); Iteration = 1; - LastIterations = false; EasyMove = rml.scan_for_easy_move(); // Iterative deepening loop - while (!AbortSearch && Iteration < PLY_MAX) + while (Iteration < PLY_MAX) { // Initialize iteration rml.sort(); @@ -681,8 +679,62 @@ namespace { std::cout << "info depth " << Iteration << std::endl; + // Calculate dynamic search window based on previous iterations + Value alpha, beta; + + if (MultiPV == 1 && Iteration >= 6) + { + int prevDelta1 = IterationInfo[Iteration - 1].speculatedValue - IterationInfo[Iteration - 2].speculatedValue; + int prevDelta2 = IterationInfo[Iteration - 2].speculatedValue - IterationInfo[Iteration - 3].speculatedValue; + + int delta = Max(2 * abs(prevDelta1) + abs(prevDelta2), ProblemMargin); + + alpha = Max(IterationInfo[Iteration - 1].value - delta, -VALUE_INFINITE); + beta = Min(IterationInfo[Iteration - 1].value + delta, VALUE_INFINITE); + } + else + { + alpha = - VALUE_INFINITE; + beta = VALUE_INFINITE; + } + // Search to the current depth - ValueByIteration[Iteration] = root_search(p, ss, rml); + Value value = root_search(p, ss, rml, alpha, beta); + + // Write PV to transposition table, in case the relevant entries have + // been overwritten during the search. + TT.insert_pv(p, ss[0].pv); + + if (AbortSearch) + break; // Value cannot be trusted. Break out immediately! + + //Save info about search result + Value speculatedValue; + bool fHigh = false; + bool fLow = false; + Value delta = value - IterationInfo[Iteration - 1].value; + + if (value >= beta) + { + assert(delta > 0); + + fHigh = true; + speculatedValue = value + delta; + BestMoveChangesByIteration[Iteration] += 2; // Allocate more time + } + else if (value <= alpha) + { + assert(value == alpha); + assert(delta < 0); + + fLow = true; + speculatedValue = value + delta; + BestMoveChangesByIteration[Iteration] += 3; // Allocate more time + } else + speculatedValue = value; + + speculatedValue = Min(Max(speculatedValue, -VALUE_INFINITE), VALUE_INFINITE); + IterationInfo[Iteration] = IterationInfoType(value, speculatedValue); // Erase the easy move if it differs from the new best move if (ss[0].pv[0] != EasyMove) @@ -701,13 +753,15 @@ namespace { // Stop search early when the last two iterations returned a mate score if ( Iteration >= 6 - && abs(ValueByIteration[Iteration]) >= abs(VALUE_MATE) - 100 - && abs(ValueByIteration[Iteration-1]) >= abs(VALUE_MATE) - 100) + && abs(IterationInfo[Iteration].value) >= abs(VALUE_MATE) - 100 + && abs(IterationInfo[Iteration-1].value) >= abs(VALUE_MATE) - 100) stopSearch = true; // Stop search early if one move seems to be much better than the rest int64_t nodes = nodes_searched(); if ( Iteration >= 8 + && !fLow + && !fHigh && EasyMove == ss[0].pv[0] && ( ( rml.get_move_cumulative_nodes(0) > (nodes * 85) / 100 && current_search_time() > MaxSearchTime / 16) @@ -720,9 +774,6 @@ namespace { ExtraSearchTime = BestMoveChangesByIteration[Iteration] * (MaxSearchTime / 2) + BestMoveChangesByIteration[Iteration-1] * (MaxSearchTime / 3); - // Try to guess if the current iteration is the last one or the last two - LastIterations = (current_search_time() > ((MaxSearchTime + ExtraSearchTime)*58) / 128); - // Stop search if most of MaxSearchTime is consumed at the end of the // iteration. We probably don't have enough time to search the first // move at the next iteration anyway. @@ -731,15 +782,13 @@ namespace { if (stopSearch) { + //FIXME: Implement fail-low emergency measures if (!PonderSearch) break; else StopOnPonderhit = true; } } - // Write PV to transposition table, in case the relevant entries have - // been overwritten during the search: - TT.insert_pv(p, ss[0].pv); if (MaxDepth && Iteration >= MaxDepth) break; @@ -759,6 +808,11 @@ namespace { << " hashfull " << TT.full() << std::endl; // Print the best move and the ponder move to the standard output + if (ss[0].pv[0] == MOVE_NONE) + { + ss[0].pv[0] = rml.get_move(0); + ss[0].pv[1] = MOVE_NONE; + } std::cout << "bestmove " << ss[0].pv[0]; if (ss[0].pv[1] != MOVE_NONE) std::cout << " ponder " << ss[0].pv[1]; @@ -791,15 +845,23 @@ namespace { // scheme (perhaps we should try to use this at internal PV nodes, too?) // and prints some information to the standard output. - Value root_search(Position &pos, SearchStack ss[], RootMoveList &rml) { + Value root_search(Position &pos, SearchStack ss[], RootMoveList &rml, Value alpha, Value beta) { - Value alpha = -VALUE_INFINITE; - Value beta = VALUE_INFINITE, value; + Value oldAlpha = alpha; + Value value; Bitboard dcCandidates = pos.discovered_check_candidates(pos.side_to_move()); // Loop through all the moves in the root move list for (int i = 0; i < rml.move_count() && !AbortSearch; i++) { + if (alpha >= beta) + { + // We failed high, invalidate and skip next moves, leave node-counters + // and beta-counters as they are and quickly return, we will try to do + // a research at the next iteration with a bigger aspiration window. + rml.set_move_score(i, -VALUE_INFINITE); + continue; + } int64_t nodes; Move move; StateInfo st; @@ -832,12 +894,12 @@ namespace { if (i < MultiPV) { - value = -search_pv(pos, ss, -beta, VALUE_INFINITE, newDepth, 1, 0); + 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 // for time managment: When Problem is true, we try to complete the // current iteration before playing a move. - Problem = (Iteration >= 2 && value <= ValueByIteration[Iteration-1] - ProblemMargin); + Problem = (Iteration >= 2 && value <= IterationInfo[Iteration-1].value - ProblemMargin); if (Problem && StopOnPonderhit) StopOnPonderhit = false; @@ -862,7 +924,7 @@ namespace { // 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: + // move and/or PV. if (AbortSearch) break; @@ -881,7 +943,7 @@ namespace { rml.set_move_score(i, -VALUE_INFINITE); else { - // New best move! + // PV move or new best move! // Update PV rml.set_move_score(i, value); @@ -913,11 +975,12 @@ namespace { LogFile << pretty_pv(pos, current_search_time(), Iteration, nodes_searched(), value, ss[0].pv) << std::endl; - alpha = value; + if (value > alpha) + alpha = value; // Reset the global variable Problem to false if the value isn't too // far below the final value from the last iteration. - if (value > ValueByIteration[Iteration - 1] - NoProblemMargin) + if (value > IterationInfo[Iteration - 1].value - NoProblemMargin) Problem = false; } else // MultiPV > 1 @@ -941,7 +1004,11 @@ namespace { } alpha = rml.get_move_score(Min(i, MultiPV-1)); } - } + } // New best move case + + assert(alpha >= oldAlpha); + + FailLow = (alpha == oldAlpha); } return alpha; } @@ -962,7 +1029,7 @@ namespace { // Initialize, and make an early exit in case of an aborted search, // an instant draw, maximum ply reached, etc. - init_node(pos, ss, ply, threadID); + init_node(ss, ply, threadID); // After init_node() that calls poll() if (AbortSearch || thread_should_stop(threadID)) @@ -985,7 +1052,7 @@ namespace { // Transposition table lookup. At PV nodes, we don't use the TT for // pruning, but only for move ordering. - const TTEntry* tte = TT.retrieve(pos); + const TTEntry* tte = TT.retrieve(pos.get_key()); Move ttMove = (tte ? tte->move() : MOVE_NONE); // Go with internal iterative deepening if we don't have a TT move @@ -1021,12 +1088,6 @@ namespace { movesSearched[moveCount++] = ss[ply].currentMove = move; - if (moveIsCapture) - ss[ply].currentMoveCaptureValue = - move_is_ep(move)? PawnValueMidgame : pos.midgame_value_of_piece_on(move_to(move)); - else - ss[ply].currentMoveCaptureValue = Value(0); - // Decide the new search depth bool dangerous; Depth ext = extension(pos, move, true, moveIsCapture, moveIsCheck, singleReply, mateThreat, &dangerous); @@ -1096,7 +1157,7 @@ namespace { // (from the computer's point of view) since the previous iteration: if ( ply == 1 && Iteration >= 2 - && -value <= ValueByIteration[Iteration-1] - ProblemMargin) + && -value <= IterationInfo[Iteration-1].value - ProblemMargin) Problem = true; } @@ -1124,7 +1185,7 @@ namespace { return bestValue; if (bestValue <= oldAlpha) - TT.store(pos, value_to_tt(bestValue, ply), depth, MOVE_NONE, VALUE_TYPE_UPPER); + TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_UPPER, depth, MOVE_NONE); else if (bestValue >= beta) { @@ -1135,10 +1196,10 @@ namespace { update_history(pos, m, depth, movesSearched, moveCount); update_killers(m, ss[ply]); } - TT.store(pos, value_to_tt(bestValue, ply), depth, m, VALUE_TYPE_LOWER); + TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, depth, m); } else - TT.store(pos, value_to_tt(bestValue, ply), depth, ss[ply].pv[ply], VALUE_TYPE_EXACT); + TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_EXACT, depth, ss[ply].pv[ply]); return bestValue; } @@ -1158,7 +1219,7 @@ namespace { // Initialize, and make an early exit in case of an aborted search, // an instant draw, maximum ply reached, etc. - init_node(pos, ss, ply, threadID); + init_node(ss, ply, threadID); // After init_node() that calls poll() if (AbortSearch || thread_should_stop(threadID)) @@ -1180,7 +1241,7 @@ namespace { return beta - 1; // Transposition table lookup - const TTEntry* tte = TT.retrieve(pos); + const TTEntry* tte = TT.retrieve(pos.get_key()); Move ttMove = (tte ? tte->move() : MOVE_NONE); if (tte && ok_to_use_TT(tte, depth, beta, ply)) @@ -1191,7 +1252,6 @@ namespace { Value approximateEval = quick_evaluate(pos); bool mateThreat = false; - bool nullDrivenIID = false; bool isCheck = pos.is_check(); // Null move search @@ -1206,23 +1266,10 @@ namespace { StateInfo st; pos.do_null_move(st); - int R = (depth >= 4 * OnePly ? 4 : 3); // Null move dynamic reduction + int R = (depth >= 5 * OnePly ? 4 : 3); // Null move dynamic reduction Value nullValue = -search(pos, ss, -(beta-1), depth-R*OnePly, ply+1, false, threadID); - // Check for a null capture artifact, if the value without the null capture - // is above beta then mark the node as a suspicious failed low. We will verify - // later if we are really under threat. - if ( UseNullDrivenIID - && nullValue < beta - && depth > 6 * OnePly - &&!value_is_mate(nullValue) - && ttMove == MOVE_NONE - && ss[ply + 1].currentMove != MOVE_NONE - && pos.move_is_capture(ss[ply + 1].currentMove) - && pos.see(ss[ply + 1].currentMove) + nullValue >= beta) - nullDrivenIID = true; - pos.undo_null_move(); if (value_is_mate(nullValue)) @@ -1246,10 +1293,8 @@ namespace { // low score (which will cause the reduced move to fail high in the // parent node, which will trigger a re-search with full depth). if (nullValue == value_mated_in(ply + 2)) - { mateThreat = true; - nullDrivenIID = false; - } + ss[ply].threatMove = ss[ply + 1].currentMove; if ( depth < ThreatDepth && ss[ply - 1].reduction @@ -1259,17 +1304,15 @@ namespace { } // Null move search not allowed, try razoring else if ( !value_is_mate(beta) - && approximateEval < beta - RazorMargin && depth < RazorDepth - && (RazorAtDepthOne || depth > OnePly) + && approximateEval < beta - RazorApprMargins[int(depth) - 2] + && ss[ply - 1].currentMove != MOVE_NULL && ttMove == MOVE_NONE && !pos.has_pawn_on_7th(pos.side_to_move())) { Value v = qsearch(pos, ss, beta-1, beta, Depth(0), ply, threadID); - if ( (v < beta - RazorMargin - RazorMargin / 4) - || (depth < 3*OnePly && v < beta - RazorMargin) - || (depth < 2*OnePly && v < beta - RazorMargin / 2)) - return v; + if (v < beta - RazorMargins[int(depth) - 2]) + return v; } // Go with internal iterative deepening if we don't have a TT move @@ -1279,22 +1322,6 @@ namespace { search(pos, ss, beta, Min(depth/2, depth-2*OnePly), ply, false, threadID); ttMove = ss[ply].pv[ply]; } - else if (nullDrivenIID) - { - // The null move failed low due to a suspicious capture. Perhaps we - // are facing a null capture artifact due to the side to move change - // and this position should fail high. So do a normal search with a - // reduced depth to get a good ttMove to use in the following full - // depth search. - Move tm = ss[ply].threatMove; - - assert(tm != MOVE_NONE); - assert(ttMove == MOVE_NONE); - - search(pos, ss, beta, depth/2, ply, false, threadID); - ttMove = ss[ply].pv[ply]; - ss[ply].threatMove = tm; - } // Initialize a MovePicker object for the current position, and prepare // to search all moves: @@ -1340,12 +1367,11 @@ namespace { continue; // Value based pruning - if (depth < 7 * OnePly && approximateEval < beta) + if (approximateEval < beta) { if (futilityValue == VALUE_NONE) futilityValue = evaluate(pos, ei, threadID) - + FutilityMargins[int(depth)/2 - 1] - + 32 * (depth & 1); + + FutilityMargins[int(depth) - 2]; if (futilityValue < beta) { @@ -1420,7 +1446,7 @@ namespace { return bestValue; if (bestValue < beta) - TT.store(pos, value_to_tt(bestValue, ply), depth, MOVE_NONE, VALUE_TYPE_UPPER); + TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_UPPER, depth, MOVE_NONE); else { BetaCounter.add(pos.side_to_move(), depth, threadID); @@ -1430,8 +1456,11 @@ namespace { update_history(pos, m, depth, movesSearched, moveCount); update_killers(m, ss[ply]); } - TT.store(pos, value_to_tt(bestValue, ply), depth, m, VALUE_TYPE_LOWER); + TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, depth, m); } + + assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE); + return bestValue; } @@ -1451,7 +1480,7 @@ namespace { // Initialize, and make an early exit in case of an aborted search, // an instant draw, maximum ply reached, etc. - init_node(pos, ss, ply, threadID); + init_node(ss, ply, threadID); // After init_node() that calls poll() if (AbortSearch || thread_should_stop(threadID)) @@ -1460,15 +1489,40 @@ namespace { if (pos.is_draw()) return VALUE_DRAW; - // Transposition table lookup - const TTEntry* tte = TT.retrieve(pos); - if (tte && ok_to_use_TT(tte, depth, beta, ply)) - return value_from_tt(tte->value(), ply); + // Transposition table lookup, only when not in PV + TTEntry* tte = NULL; + bool pvNode = (beta - alpha != 1); + if (!pvNode) + { + tte = TT.retrieve(pos.get_key()); + if (tte && ok_to_use_TT(tte, depth, beta, ply)) + { + assert(tte->type() != VALUE_TYPE_EVAL); + + return value_from_tt(tte->value(), ply); + } + } + Move ttMove = (tte ? tte->move() : MOVE_NONE); // Evaluate the position statically EvalInfo ei; + Value staticValue; bool isCheck = pos.is_check(); - Value staticValue = (isCheck ? -VALUE_INFINITE : evaluate(pos, ei, threadID)); + ei.futilityMargin = Value(0); // Manually initialize futilityMargin + + if (isCheck) + staticValue = -VALUE_INFINITE; + + else if (tte && tte->type() == VALUE_TYPE_EVAL) + { + // Use the cached evaluation score if possible + assert(tte->value() == evaluate(pos, ei, threadID)); + assert(ei.futilityMargin == Value(0)); + + staticValue = tte->value(); + } + else + staticValue = evaluate(pos, ei, threadID); if (ply == PLY_MAX - 1) return evaluate(pos, ei, threadID); @@ -1478,7 +1532,13 @@ namespace { Value bestValue = staticValue; if (bestValue >= beta) + { + // Store the score to avoid a future costly evaluation() call + if (!isCheck && !tte && ei.futilityMargin == 0) + TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_EVAL, Depth(-127*OnePly), MOVE_NONE); + return bestValue; + } if (bestValue > alpha) alpha = bestValue; @@ -1486,8 +1546,7 @@ 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. - bool pvNode = (beta - alpha != 1); - MovePicker mp = MovePicker(pos, pvNode, MOVE_NONE, EmptySearchStack, depth, isCheck ? NULL : &ei); + MovePicker mp = MovePicker(pos, pvNode, ttMove, EmptySearchStack, depth); Move move; int moveCount = 0; Bitboard dcCandidates = mp.discovered_check_candidates(); @@ -1564,15 +1623,20 @@ namespace { assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE); // Update transposition table - TT.store(pos, value_to_tt(bestValue, ply), depth, MOVE_NONE, VALUE_TYPE_EXACT); + Move m = ss[ply].pv[ply]; + if (!pvNode) + { + Depth d = (depth == Depth(0) ? Depth(0) : Depth(-1)); + if (bestValue < beta) + TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_UPPER, d, MOVE_NONE); + else + TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, d, m); + } // Update killers only for good check moves - Move m = ss[ply].currentMove; if (alpha >= beta && ok_to_history(pos, m)) // Only non capture moves are considered - { - // Wrong to update history when depth is <= 0 update_killers(m, ss[ply]); - } + return bestValue; } @@ -1720,12 +1784,6 @@ namespace { assert(move_is_ok(move)); - if (moveIsCapture) - ss[sp->ply].currentMoveCaptureValue = - move_is_ep(move)? PawnValueMidgame : pos.midgame_value_of_piece_on(move_to(move)); - else - ss[sp->ply].currentMoveCaptureValue = Value(0); - lock_grab(&(sp->lock)); int moveCount = ++sp->moves; lock_release(&(sp->lock)); @@ -1808,7 +1866,7 @@ namespace { // (from the computer's point of view) since the previous iteration. if ( sp->ply == 1 && Iteration >= 2 - && -value <= ValueByIteration[Iteration-1] - ProblemMargin) + && -value <= IterationInfo[Iteration-1].value - ProblemMargin) Problem = true; } lock_release(&(sp->lock)); @@ -1861,7 +1919,7 @@ namespace { // Constructor RootMove::RootMove() { - nodes = cumulativeNodes = 0ULL; + nodes = cumulativeNodes = ourBeta = theirBeta = 0ULL; } // RootMove::operator<() is the comparison function used when @@ -1897,22 +1955,20 @@ namespace { for (int k = 0; !includeMove && searchMoves[k] != MOVE_NONE; k++) includeMove = (searchMoves[k] == mlist[i].move); - if (includeMove) - { - // Find a quick score for the move - StateInfo st; - SearchStack ss[PLY_MAX_PLUS_2]; - - moves[count].move = mlist[i].move; - moves[count].nodes = 0ULL; - pos.do_move(moves[count].move, st); - moves[count].score = -qsearch(pos, ss, -VALUE_INFINITE, VALUE_INFINITE, - Depth(0), 1, 0); - pos.undo_move(moves[count].move); - moves[count].pv[0] = moves[i].move; - moves[count].pv[1] = MOVE_NONE; // FIXME - count++; - } + if (!includeMove) + continue; + + // Find a quick score for the move + StateInfo st; + SearchStack ss[PLY_MAX_PLUS_2]; + + moves[count].move = mlist[i].move; + pos.do_move(moves[count].move, st); + moves[count].score = -qsearch(pos, ss, -VALUE_INFINITE, VALUE_INFINITE, Depth(0), 1, 0); + pos.undo_move(moves[count].move); + moves[count].pv[0] = moves[count].move; + moves[count].pv[1] = MOVE_NONE; // FIXME + count++; } sort(); } @@ -2016,7 +2072,7 @@ namespace { // NodesBetweenPolls nodes, init_node() also calls poll(), which polls // for user input and checks whether it is time to stop the search. - void init_node(const Position &pos, SearchStack ss[], int ply, int threadID) { + void init_node(SearchStack ss[], int ply, int threadID) { assert(ply >= 0 && ply < PLY_MAX); assert(threadID >= 0 && threadID < ActiveThreads); @@ -2437,11 +2493,11 @@ namespace { return; bool overTime = t > AbsoluteMaxSearchTime - || (RootMoveNumber == 1 && t > MaxSearchTime + ExtraSearchTime) - || ( !FailHigh && !fail_high_ply_1() && !Problem + || (RootMoveNumber == 1 && t > MaxSearchTime + ExtraSearchTime && !FailLow) //FIXME: We are not checking any problem flags, BUG? + || ( !FailHigh && !FailLow && !fail_high_ply_1() && !Problem && t > 6*(MaxSearchTime + ExtraSearchTime)); - if ( (Iteration >= 2 && (!InfiniteSearch && overTime)) + if ( (Iteration >= 3 && (!InfiniteSearch && overTime)) || (ExactMaxTime && t >= ExactMaxTime) || (Iteration >= 3 && MaxNodes && nodes_searched() >= MaxNodes)) AbortSearch = true; @@ -2455,12 +2511,12 @@ namespace { void ponderhit() { int t = current_search_time(); PonderSearch = false; - if(Iteration >= 2 && + if(Iteration >= 3 && (!InfiniteSearch && (StopOnPonderhit || t > AbsoluteMaxSearchTime || (RootMoveNumber == 1 && - t > MaxSearchTime + ExtraSearchTime) || - (!FailHigh && !fail_high_ply_1() && !Problem && + t > MaxSearchTime + ExtraSearchTime && !FailLow) || + (!FailHigh && !FailLow && !fail_high_ply_1() && !Problem && t > 6*(MaxSearchTime + ExtraSearchTime))))) AbortSearch = true; } @@ -2502,7 +2558,6 @@ namespace { command = "quit"; if(command == "quit") { - OpeningBook.close(); stop_threads(); quit_eval(); exit(0);