X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=a3912603b5af90ea0e60d69293f6d884b0946fc1;hp=b8d6a3a58ef7d3f6f953eca5f0665cec2a1b0cc6;hb=342ceb1c9124ced53650d6c422a8cfa32e0b12ef;hpb=3e7e1a7c53c251c244d8271082b602e6b9a9b208 diff --git a/src/search.cpp b/src/search.cpp index b8d6a3a5..a3912603 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -23,6 +23,7 @@ //// #include +#include #include #include #include @@ -47,57 +48,23 @@ namespace { /// Types - //The IterationInfoType is used to store search history - //iteration by iteration. + // 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 "speculated value" and then move on... - - class IterationInfoType { - private: - Value _value; - Value _speculatedValue; - bool _failHigh; - bool _failLow; - public: - IterationInfoType() { - clear(); - } - - inline void clear() { - set(Value(0)); - } + // 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. - inline void set(Value v) { - set(v, v, false, false); - } - - inline void set(Value v, Value specV, bool fHigh, bool fLow) { - _value = v; - _speculatedValue = specV; - _failHigh = fHigh; - _failLow = fLow; - } + struct IterationInfoType { - inline Value value() { - return _value; - } - - inline Value speculated_value() { - return _speculatedValue; - } - - inline bool fail_high() { - return _failHigh; - } + IterationInfoType(Value v = Value(0), Value sv = Value(0)) + : value(v), speculatedValue(sv) {} - inline bool fail_low() { - return _failLow; - } + Value value, speculatedValue; }; @@ -162,18 +129,17 @@ 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 + Depth SelectiveDepth; // Use internal iterative deepening? const bool UseIIDAtPVNodes = true; @@ -210,33 +176,35 @@ 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); + + //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 bool RazorAtDepthOne = false; - Depth RazorDepth = 4*OnePly; - Value RazorMargin = Value(0x300); + 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(0x100000), 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*/; @@ -254,7 +222,7 @@ namespace { int BestMoveChangesByIteration[PLY_MAX_PLUS_2]; // MultiPV mode - int MultiPV = 1; + int MultiPV; // Time managment variables int SearchStartTime; @@ -274,15 +242,15 @@ namespace { 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; @@ -301,14 +269,10 @@ namespace { /// Functions Value id_loop(const Position &pos, Move searchMoves[]); - 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); + 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(SearchStack ss[], int ply, int threadID); @@ -480,13 +444,13 @@ void think(const Position &pos, bool infinite, bool ponder, int side_to_move, 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; + //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")); + //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; @@ -711,7 +675,7 @@ namespace { ss[i].init(i); ss[i].initKillers(); } - IterationInfo[1].set(rml.get_move_score(0)); + IterationInfo[1] = IterationInfoType(rml.get_move_score(0), rml.get_move_score(0)); Iteration = 1; EasyMove = rml.scan_for_easy_move(); @@ -728,59 +692,62 @@ namespace { std::cout << "info depth " << Iteration << std::endl; - //Calculate dynamic search window based on previous iterations. - Value alpha; - Value beta; - - if (MultiPV == 1 && Iteration >= 6) { - Value prevDelta1 = IterationInfo[Iteration - 1].speculated_value() - IterationInfo[Iteration - 2].speculated_value(); - Value prevDelta2 = IterationInfo[Iteration - 2].speculated_value() - IterationInfo[Iteration - 3].speculated_value(); + // Calculate dynamic search window based on previous iterations + Value alpha, beta; - Value delta = Max((2 * Abs(prevDelta1) + Abs(prevDelta2)) , ProblemMargin); + 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; - alpha = IterationInfo[Iteration - 1].value() - delta; - beta = IterationInfo[Iteration - 1].value() + delta; - if (alpha < - VALUE_INFINITE) alpha = - VALUE_INFINITE; - if (beta > VALUE_INFINITE) beta = VALUE_INFINITE; + int delta = Max(2 * abs(prevDelta1) + abs(prevDelta2), ProblemMargin); - } else { - alpha = - VALUE_INFINITE; - beta = VALUE_INFINITE; + 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 Value value = root_search(p, ss, rml, alpha, beta); - if (AbortSearch) - break; //Value cannot be trusted. Break out immediately! // Write PV to transposition table, in case the relevant entries have - // been overwritten during the search: + // 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 speculated_value = value; + Value speculatedValue; bool fHigh = false; bool fLow = false; + Value delta = value - IterationInfo[Iteration - 1].value; - Value prev_value = IterationInfo[Iteration - 1].value(); - Value delta = value - prev_value; - - if (value >= beta) { - fHigh = true; - speculated_value = prev_value + 2 * delta; - BestMoveChangesByIteration[Iteration] += 2; //This is used to tell time management to allocate more time - } else if (value <= alpha) { - fLow = true; - speculated_value = prev_value + 2 * delta; - BestMoveChangesByIteration[Iteration] += 3; //This is used to tell time management to allocate more time - } else { - //nothing + 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); - if (speculated_value < - VALUE_INFINITE) speculated_value = - VALUE_INFINITE; - if (speculated_value > VALUE_INFINITE) speculated_value = VALUE_INFINITE; + fLow = true; + speculatedValue = value + delta; + BestMoveChangesByIteration[Iteration] += 3; // Allocate more time + } else + speculatedValue = value; - IterationInfo[Iteration].set(value, speculated_value, fHigh, fLow); + 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) @@ -799,13 +766,15 @@ namespace { // Stop search early when the last two iterations returned a mate score if ( Iteration >= 6 - && abs(IterationInfo[Iteration].value()) >= abs(VALUE_MATE) - 100 - && abs(IterationInfo[Iteration-1].value()) >= 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 + if ( Iteration >= 8 + && !fLow + && !fHigh && EasyMove == ss[0].pv[0] && ( ( rml.get_move_cumulative_nodes(0) > (nodes * 85) / 100 && current_search_time() > MaxSearchTime / 16) @@ -891,7 +860,6 @@ namespace { Value root_search(Position &pos, SearchStack ss[], RootMoveList &rml, Value alpha, Value beta) { - //FIXME: Implement bestValue Value oldAlpha = alpha; Value value; Bitboard dcCandidates = pos.discovered_check_candidates(pos.side_to_move()); @@ -899,12 +867,14 @@ namespace { // Loop through all the moves in the root move list for (int i = 0; i < rml.move_count() && !AbortSearch; i++) { - if (alpha >= beta) { - rml.set_move_score(i, -VALUE_INFINITE); - //Leave node-counters and beta-counters as they are. - continue; + 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; @@ -942,7 +912,7 @@ namespace { // 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 <= IterationInfo[Iteration-1].value() - ProblemMargin); + Problem = (Iteration >= 2 && value <= IterationInfo[Iteration-1].value - ProblemMargin); if (Problem && StopOnPonderhit) StopOnPonderhit = false; @@ -967,7 +937,7 @@ 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; @@ -986,7 +956,7 @@ 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); @@ -1019,11 +989,11 @@ namespace { << std::endl; if (value > alpha) - alpha = value; + 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 > IterationInfo[Iteration - 1].value() - NoProblemMargin) + if (value > IterationInfo[Iteration - 1].value - NoProblemMargin) Problem = false; } else // MultiPV > 1 @@ -1047,13 +1017,11 @@ namespace { } alpha = rml.get_move_score(Min(i, MultiPV-1)); } - } + } // New best move case - if (alpha <= oldAlpha) - FailLow = true; - else - FailLow = false; + assert(alpha >= oldAlpha); + FailLow = (alpha == oldAlpha); } return alpha; } @@ -1202,7 +1170,7 @@ namespace { // (from the computer's point of view) since the previous iteration: if ( ply == 1 && Iteration >= 2 - && -value <= IterationInfo[Iteration-1].value() - ProblemMargin) + && -value <= IterationInfo[Iteration-1].value - ProblemMargin) Problem = true; } @@ -1349,17 +1317,14 @@ 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] && 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 <= 2*OnePly && v < beta - RazorMargin) - || (depth <= 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 @@ -1418,8 +1383,7 @@ namespace { { if (futilityValue == VALUE_NONE) futilityValue = evaluate(pos, ei, threadID) - + FutilityMargins[int(depth)/2 - 1] - + 32 * (depth & 1); + + FutilityMargins[int(depth) - 2]; if (futilityValue < beta) { @@ -1550,6 +1514,7 @@ namespace { return value_from_tt(tte->value(), ply); } } + Move ttMove = (tte ? tte->move() : MOVE_NONE); // Evaluate the position statically EvalInfo ei; @@ -1593,7 +1558,7 @@ 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, MOVE_NONE, EmptySearchStack, depth); + MovePicker mp = MovePicker(pos, pvNode, ttMove, EmptySearchStack, depth); Move move; int moveCount = 0; Bitboard dcCandidates = mp.discovered_check_candidates(); @@ -1670,22 +1635,20 @@ namespace { assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE); // Update transposition table + Move m = ss[ply].pv[ply]; if (!pvNode) { Depth d = (depth == Depth(0) ? Depth(0) : Depth(-1)); if (bestValue < beta) TT.store(pos, value_to_tt(bestValue, ply), d, MOVE_NONE, VALUE_TYPE_UPPER); else - TT.store(pos, value_to_tt(bestValue, ply), d, MOVE_NONE, VALUE_TYPE_LOWER); + TT.store(pos, value_to_tt(bestValue, ply), d, m, VALUE_TYPE_LOWER); } // 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; } @@ -1915,7 +1878,7 @@ namespace { // (from the computer's point of view) since the previous iteration. if ( sp->ply == 1 && Iteration >= 2 - && -value <= IterationInfo[Iteration-1].value() - ProblemMargin) + && -value <= IterationInfo[Iteration-1].value - ProblemMargin) Problem = true; } lock_release(&(sp->lock)); @@ -2544,7 +2507,7 @@ namespace { return; bool overTime = t > AbsoluteMaxSearchTime - || (RootMoveNumber == 1 && t > MaxSearchTime + ExtraSearchTime && !FailLow) //FIXME: BUG?? + || (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));