X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=fa7052d0dc0c2605201a17bd283742541e1c3c59;hp=7aab835d93d36a7b7eba9db7479ca5a1716cd3af;hb=c295599e4ad481f677b14cb0be14174b61ebff81;hpb=66c5835080c8c1dab6bf203d2b6d9db6ab9439cc diff --git a/src/search.cpp b/src/search.cpp index 7aab835d..fa7052d0 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -38,6 +38,7 @@ #include "lock.h" #include "san.h" #include "search.h" +#include "timeman.h" #include "thread.h" #include "tt.h" #include "ucioption.h" @@ -90,7 +91,7 @@ namespace { template void split(const Position& pos, SearchStack* ss, int ply, Value* alpha, const Value beta, Value* bestValue, - Depth depth, bool mateThreat, int* moveCount, MovePicker* mp, bool pvNode); + Depth depth, Move threatMove, bool mateThreat, int* moveCount, MovePicker* mp, bool pvNode); private: friend void poll(); @@ -198,7 +199,7 @@ namespace { Depth PassedPawnExtension[2], PawnEndgameExtension[2], MateThreatExtension[2]; // Minimum depth for use of singular extension - const Depth SingularExtensionDepth[2] = { 8 * OnePly /* non-PV */, 6 * OnePly /* PV */}; + const Depth SingularExtensionDepth[2] = { 7 * OnePly /* non-PV */, 6 * OnePly /* PV */}; // If the TT move is at least SingularExtensionMargin better then the // remaining ones we will extend it. @@ -250,10 +251,10 @@ namespace { int MultiPV; // Time managment variables - int SearchStartTime, MaxNodes, MaxDepth, MaxSearchTime; - int AbsoluteMaxSearchTime, ExtraSearchTime, ExactMaxTime; + int SearchStartTime, MaxNodes, MaxDepth, ExactMaxTime; bool UseTimeManagement, InfiniteSearch, PonderSearch, StopOnPonderhit; bool FirstRootMove, AbortSearch, Quit, AspirationFailLow; + TimeManager TimeMgr; // Log file bool UseLogFile; @@ -309,6 +310,8 @@ namespace { void wait_for_stop_or_ponderhit(); void init_ss_array(SearchStack* ss, int size); void print_pv_info(const Position& pos, Move pv[], Value alpha, Value beta, Value value); + void insert_pv_in_tt(const Position& pos, Move pv[]); + void extract_pv_from_tt(const Position& pos, Move bestMove, Move pv[]); #if !defined(_MSC_VER) void *init_thread(void *threadID); @@ -358,20 +361,6 @@ void init_search() { } -// SearchStack::init() initializes a search stack entry. -// Called at the beginning of search() when starting to examine a new node. -void SearchStack::init() { - - currentMove = threatMove = bestMove = MOVE_NONE; -} - -// SearchStack::initKillers() initializes killers for a search stack entry -void SearchStack::initKillers() { - - killers[0] = killers[1] = mateKiller = MOVE_NONE; -} - - /// 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. @@ -412,7 +401,6 @@ bool think(const Position& pos, bool infinite, bool ponder, int time[], int incr // Initialize global search variables StopOnPonderhit = AbortSearch = Quit = AspirationFailLow = false; - MaxSearchTime = AbsoluteMaxSearchTime = ExtraSearchTime = 0; NodesSincePoll = 0; TM.resetNodeCounters(); SearchStartTime = get_system_time(); @@ -484,40 +472,7 @@ bool think(const Position& pos, bool infinite, bool ponder, int time[], int incr int myTime = time[pos.side_to_move()]; int myIncrement = increment[pos.side_to_move()]; if (UseTimeManagement) - { - if (!movesToGo) // Sudden death time control - { - 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) - { - MaxSearchTime = myTime / 2; - AbsoluteMaxSearchTime = (myTime > 3000)? (myTime - 500) : ((myTime * 3) / 4); - } - else - { - MaxSearchTime = myTime / Min(movesToGo, 20); - AbsoluteMaxSearchTime = Min((4 * myTime) / movesToGo, myTime / 3); - } - } - - if (get_option_value_bool("Ponder")) - { - MaxSearchTime += MaxSearchTime / 4; - MaxSearchTime = Min(MaxSearchTime, AbsoluteMaxSearchTime); - } - } + TimeMgr.update(myTime, myIncrement, movesToGo, pos.startpos_ply_counter()); // Set best NodesBetweenPolls interval to avoid lagging under // heavy time pressure. @@ -628,7 +583,7 @@ namespace { // Write PV to transposition table, in case the relevant entries have // been overwritten during the search. - TT.insert_pv(p, pv); + insert_pv_in_tt(p, pv); if (AbortSearch) break; // Value cannot be trusted. Break out immediately! @@ -661,20 +616,20 @@ namespace { if ( Iteration >= 8 && EasyMove == pv[0] && ( ( rml.get_move_cumulative_nodes(0) > (nodes * 85) / 100 - && current_search_time() > MaxSearchTime / 16) + && current_search_time() > TimeMgr.optimumSearchTime / 16) ||( rml.get_move_cumulative_nodes(0) > (nodes * 98) / 100 - && current_search_time() > MaxSearchTime / 32))) + && current_search_time() > TimeMgr.optimumSearchTime / 32))) stopSearch = true; // Add some extra time if the best move has changed during the last two iterations if (Iteration > 5 && Iteration <= 50) - ExtraSearchTime = BestMoveChangesByIteration[Iteration] * (MaxSearchTime / 2) - + BestMoveChangesByIteration[Iteration-1] * (MaxSearchTime / 3); + TimeMgr.best_move_changes(BestMoveChangesByIteration[Iteration], + BestMoveChangesByIteration[Iteration-1]); // 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. - if (current_search_time() > ((MaxSearchTime + ExtraSearchTime) * 80) / 128) + if (current_search_time() > (TimeMgr.available_time() * 80) / 128) stopSearch = true; if (stopSearch) @@ -760,7 +715,9 @@ namespace { beta = *betaPtr; isCheck = pos.is_check(); - // Step 1. Initialize node and poll (omitted at root, init_ss_array() has already initialized root node) + // Step 1. Initialize node (polling is omitted at root) + ss->currentMove = ss->bestMove = MOVE_NONE; + // Step 2. Check for aborted search (omitted at root) // Step 3. Mate distance pruning (omitted at root) // Step 4. Transposition table lookup (omitted at root) @@ -893,7 +850,7 @@ namespace { // the score before research in case we run out of time while researching. rml.set_move_score(i, value); ss->bestMove = move; - TT.extract_pv(pos, move, pv, PLY_MAX); + extract_pv_from_tt(pos, move, pv); rml.set_move_pv(i, pv); // Print information to the standard output @@ -933,7 +890,7 @@ namespace { // Update PV rml.set_move_score(i, value); ss->bestMove = move; - TT.extract_pv(pos, move, pv, PLY_MAX); + extract_pv_from_tt(pos, move, pv); rml.set_move_pv(i, pv); if (MultiPV == 1) @@ -1012,9 +969,9 @@ namespace { Move movesSearched[256]; EvalInfo ei; StateInfo st; - const TTEntry* tte; + const TTEntry *tte, *ttx; Key posKey; - Move ttMove, move, excludedMove; + Move ttMove, move, excludedMove, threatMove; Depth ext, newDepth; Value bestValue, value, oldAlpha; Value refinedValue, nullValue, futilityValueScaled; // Non-PV specific @@ -1027,8 +984,8 @@ namespace { // Step 1. Initialize node and poll. Polling can abort search TM.incrementNodeCounter(threadID); - ss->init(); - (ss+2)->initKillers(); + ss->currentMove = ss->bestMove = threatMove = MOVE_NONE; + (ss+2)->killers[0] = (ss+2)->killers[1] = (ss+2)->mateKiller = MOVE_NONE; if (threadID == 0 && ++NodesSincePoll > NodesBetweenPolls) { @@ -1072,28 +1029,31 @@ namespace { // Refresh tte entry to avoid aging TT.store(posKey, tte->value(), tte->type(), tte->depth(), ttMove, tte->static_value(), tte->king_danger()); - ss->currentMove = ttMove; // Can be MOVE_NONE + ss->bestMove = ttMove; // Can be MOVE_NONE return value_from_tt(tte->value(), ply); } - // Step 5. Evaluate the position statically - // At PV nodes we do this only to update gain statistics + // Step 5. Evaluate the position statically and + // update gain statistics of parent move. isCheck = pos.is_check(); - if (!isCheck) + if (isCheck) + ss->eval = VALUE_NONE; + else if (tte) { - if (tte && tte->static_value() != VALUE_NONE) - { - ss->eval = tte->static_value(); - ei.kingDanger[pos.side_to_move()] = tte->king_danger(); - } - else - ss->eval = evaluate(pos, ei); + assert(tte->static_value() != VALUE_NONE); - refinedValue = refine_eval(tte, ss->eval, ply); // Enhance accuracy with TT value if possible - update_gains(pos, (ss-1)->currentMove, (ss-1)->eval, ss->eval); + ss->eval = tte->static_value(); + ei.kingDanger[pos.side_to_move()] = tte->king_danger(); + refinedValue = refine_eval(tte, ss->eval, ply); } else - ss->eval = VALUE_NONE; + { + refinedValue = ss->eval = evaluate(pos, ei); + TT.store(posKey, VALUE_NONE, VALUE_TYPE_NONE, DEPTH_NONE, MOVE_NONE, ss->eval, ei.kingDanger[pos.side_to_move()]); + } + + // Save gain for the parent non-capture move + update_gains(pos, (ss-1)->currentMove, (ss-1)->eval, ss->eval); // Step 6. Razoring (is omitted in PV nodes) if ( !PvNode @@ -1105,10 +1065,6 @@ namespace { && !value_is_mate(beta) && !pos.has_pawn_on_7th(pos.side_to_move())) { - // Pass ss->eval to qsearch() and avoid an evaluate call - if (!tte || tte->static_value() == VALUE_NONE) - TT.store(posKey, ss->eval, VALUE_TYPE_EXACT, Depth(-127*OnePly), MOVE_NONE, ss->eval, ei.kingDanger[pos.side_to_move()]); - Value rbeta = beta - razor_margin(depth); Value v = qsearch(pos, ss, rbeta-1, rbeta, Depth(0), ply); if (v < rbeta) @@ -1123,8 +1079,8 @@ namespace { if ( !PvNode && !ss->skipNullMove && depth < RazorDepth - && refinedValue >= beta + futility_margin(depth, 0) && !isCheck + && refinedValue >= beta + futility_margin(depth, 0) && !value_is_mate(beta) && pos.non_pawn_material(pos.side_to_move())) return refinedValue - futility_margin(depth, 0); @@ -1136,8 +1092,8 @@ namespace { if ( !PvNode && !ss->skipNullMove && depth > OnePly - && refinedValue >= beta - (depth >= 4 * OnePly ? NullMoveMargin : 0) && !isCheck + && refinedValue >= beta - (depth >= 4 * OnePly ? NullMoveMargin : 0) && !value_is_mate(beta) && pos.non_pawn_material(pos.side_to_move())) { @@ -1186,10 +1142,10 @@ namespace { if (nullValue == value_mated_in(ply + 2)) mateThreat = true; - ss->threatMove = (ss+1)->currentMove; + threatMove = (ss+1)->bestMove; if ( depth < ThreatDepth && (ss-1)->reduction - && connected_moves(pos, (ss-1)->currentMove, ss->threatMove)) + && connected_moves(pos, (ss-1)->currentMove, threatMove)) return beta - 1; } } @@ -1216,9 +1172,11 @@ namespace { // Initialize a MovePicker object for the current position MovePicker mp = MovePicker(pos, ttMove, depth, H, ss, (PvNode ? -VALUE_INFINITE : beta)); CheckInfo ci(pos); + ss->bestMove = MOVE_NONE; singleEvasion = isCheck && mp.number_of_evasions() == 1; singularExtensionNode = depth >= SingularExtensionDepth[PvNode] - && tte && tte->move() + && tte + && tte->move() && !excludedMove // Do not allow recursive singular extension search && is_lower_bound(tte->type()) && tte->depth() >= depth - 3 * OnePly; @@ -1248,9 +1206,22 @@ namespace { && move == tte->move() && ext < OnePly) { + // Avoid to do an expensive singular extension search on nodes where + // such search have already been done in the past, so assume the last + // singular extension search result is still valid. + if ( !PvNode + && depth < SingularExtensionDepth[PvNode] + 5 * OnePly + && (ttx = TT.retrieve(pos.get_exclusion_key())) != NULL) + { + if (is_upper_bound(ttx->type())) + ext = OnePly; + + singularExtensionNode = false; + } + Value ttValue = value_from_tt(tte->value(), ply); - if (abs(ttValue) < VALUE_KNOWN_WIN) + if (singularExtensionNode && abs(ttValue) < VALUE_KNOWN_WIN) { Value b = ttValue - SingularExtensionMargin; ss->excludedMove = move; @@ -1258,6 +1229,7 @@ namespace { Value v = search(pos, ss, b - 1, b, depth / 2, ply); ss->skipNullMove = false; ss->excludedMove = MOVE_NONE; + ss->bestMove = MOVE_NONE; if (v < b) ext = OnePly; } @@ -1278,7 +1250,7 @@ namespace { { // Move count based pruning if ( moveCount >= futility_move_count(depth) - && !(ss->threatMove && connected_threat(pos, move, ss->threatMove)) + && !(threatMove && connected_threat(pos, move, threatMove)) && bestValue > value_mated_in(PLY_MAX)) continue; @@ -1367,7 +1339,7 @@ namespace { bestValue = value; if (value > alpha) { - if (PvNode && value < beta) // This guarantees that always: alpha < beta + if (PvNode && value < beta) // We want always alpha < beta alpha = value; if (value == value_mate_in(ply + 1)) @@ -1386,7 +1358,7 @@ namespace { && !TM.thread_should_stop(threadID) && Iteration <= 99) TM.split(pos, ss, ply, &alpha, beta, &bestValue, depth, - mateThreat, &moveCount, &mp, PvNode); + threatMove, mateThreat, &moveCount, &mp, PvNode); } // Step 19. Check for mate and stalemate @@ -1394,7 +1366,7 @@ namespace { // no legal moves, it must be mate or stalemate. // If one move was excluded return fail low score. if (!moveCount) - return excludedMove ? oldAlpha : (isCheck ? value_mated_in(ply) : VALUE_DRAW); + return excludedMove ? oldAlpha : isCheck ? value_mated_in(ply) : VALUE_DRAW; // Step 20. Update tables // If the search is not aborted, update the transposition table, @@ -1402,9 +1374,9 @@ namespace { if (AbortSearch || TM.thread_should_stop(threadID)) return bestValue; - ValueType f = (bestValue <= oldAlpha ? VALUE_TYPE_UPPER : bestValue >= beta ? VALUE_TYPE_LOWER : VALUE_TYPE_EXACT); + ValueType vt = (bestValue <= oldAlpha ? VALUE_TYPE_UPPER : bestValue >= beta ? VALUE_TYPE_LOWER : VALUE_TYPE_EXACT); move = (bestValue <= oldAlpha ? MOVE_NONE : ss->bestMove); - TT.store(posKey, value_to_tt(bestValue, ply), f, depth, move, ss->eval, ei.kingDanger[pos.side_to_move()]); + TT.store(posKey, value_to_tt(bestValue, ply), vt, depth, move, ss->eval, ei.kingDanger[pos.side_to_move()]); // Update killers and history only for non capture moves that fails high if (bestValue >= beta) @@ -1459,7 +1431,7 @@ namespace { if (!PvNode && tte && ok_to_use_TT(tte, depth, beta, ply)) { - ss->currentMove = ttMove; // Can be MOVE_NONE + ss->bestMove = ttMove; // Can be MOVE_NONE return value_from_tt(tte->value(), ply); } @@ -1474,8 +1446,10 @@ namespace { } else { - if (tte && tte->static_value() != VALUE_NONE) + if (tte) { + assert(tte->static_value() != VALUE_NONE); + ei.kingDanger[pos.side_to_move()] = tte->king_danger(); bestValue = tte->static_value(); } @@ -1489,7 +1463,7 @@ namespace { if (bestValue >= beta) { if (!tte) - TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, Depth(-127*OnePly), MOVE_NONE, ss->eval, ei.kingDanger[pos.side_to_move()]); + TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, DEPTH_NONE, MOVE_NONE, ss->eval, ei.kingDanger[pos.side_to_move()]); return bestValue; } @@ -1585,8 +1559,8 @@ namespace { // Update transposition table Depth d = (depth == Depth(0) ? Depth(0) : Depth(-1)); - ValueType f = (bestValue <= oldAlpha ? VALUE_TYPE_UPPER : bestValue >= beta ? VALUE_TYPE_LOWER : VALUE_TYPE_EXACT); - TT.store(pos.get_key(), value_to_tt(bestValue, ply), f, d, ss->bestMove, ss->eval, ei.kingDanger[pos.side_to_move()]); + ValueType vt = (bestValue <= oldAlpha ? VALUE_TYPE_UPPER : bestValue >= beta ? VALUE_TYPE_LOWER : VALUE_TYPE_EXACT); + TT.store(pos.get_key(), value_to_tt(bestValue, ply), vt, d, ss->bestMove, ss->eval, ei.kingDanger[pos.side_to_move()]); // Update killers only for checking moves that fails high if ( bestValue >= beta @@ -1659,7 +1633,7 @@ namespace { { // Move count based pruning if ( moveCount >= futility_move_count(sp->depth) - && !(ss->threatMove && connected_threat(pos, move, ss->threatMove)) + && !(sp->threatMove && connected_threat(pos, move, sp->threatMove)) && sp->bestValue > value_mated_in(PLY_MAX)) { lock_grab(&(sp->lock)); @@ -2005,8 +1979,7 @@ namespace { Value refine_eval(const TTEntry* tte, Value defaultEval, int ply) { - if (!tte) - return defaultEval; + assert(tte); Value v = value_from_tt(tte->value(), ply); @@ -2062,8 +2035,7 @@ namespace { && before != VALUE_NONE && after != VALUE_NONE && pos.captured_piece() == NO_PIECE_TYPE - && !move_is_castle(m) - && !move_is_promotion(m)) + && !move_is_special(m)) H.set_gain(pos.piece_on(move_to(m)), move_to(m), -(before + after)); } @@ -2163,9 +2135,9 @@ namespace { bool stillAtFirstMove = FirstRootMove && !AspirationFailLow - && t > MaxSearchTime + ExtraSearchTime; + && t > TimeMgr.available_time(); - bool noMoreTime = t > AbsoluteMaxSearchTime + bool noMoreTime = t > TimeMgr.maximumSearchTime || stillAtFirstMove; if ( (Iteration >= 3 && UseTimeManagement && noMoreTime) @@ -2186,9 +2158,9 @@ namespace { bool stillAtFirstMove = FirstRootMove && !AspirationFailLow - && t > MaxSearchTime + ExtraSearchTime; + && t > TimeMgr.available_time(); - bool noMoreTime = t > AbsoluteMaxSearchTime + bool noMoreTime = t > TimeMgr.maximumSearchTime || stillAtFirstMove; if (Iteration >= 3 && UseTimeManagement && (noMoreTime || StopOnPonderhit)) @@ -2208,10 +2180,7 @@ namespace { ss->reduction = Depth(0); if (i < 3) - { - ss->init(); - ss->initKillers(); - } + ss->killers[0] = ss->killers[1] = ss->mateKiller = MOVE_NONE; } } @@ -2272,6 +2241,61 @@ namespace { } + // insert_pv_in_tt() is called at the end of a search iteration, and inserts + // the PV back into the TT. This makes sure the old PV moves are searched + // first, even if the old TT entries have been overwritten. + + void insert_pv_in_tt(const Position& pos, Move pv[]) { + + StateInfo st; + TTEntry* tte; + Position p(pos, pos.thread()); + EvalInfo ei; + Value v; + + for (int i = 0; pv[i] != MOVE_NONE; i++) + { + tte = TT.retrieve(p.get_key()); + if (!tte || tte->move() != pv[i]) + { + v = (p.is_check() ? VALUE_NONE : evaluate(p, ei)); + TT.store(p.get_key(), VALUE_NONE, VALUE_TYPE_NONE, DEPTH_NONE, pv[i], v, ei.kingDanger[pos.side_to_move()]); + } + p.do_move(pv[i], st); + } + } + + + // extract_pv_from_tt() builds a PV by adding moves from the transposition table. + // We consider also failing high nodes and not only VALUE_TYPE_EXACT nodes. This + // allow to always have a ponder move even when we fail high at root and also a + // long PV to print that is important for position analysis. + + void extract_pv_from_tt(const Position& pos, Move bestMove, Move pv[]) { + + StateInfo st; + TTEntry* tte; + Position p(pos, pos.thread()); + int ply = 0; + + assert(bestMove != MOVE_NONE); + + pv[ply] = bestMove; + p.do_move(pv[ply++], st); + + while ( (tte = TT.retrieve(p.get_key())) != NULL + && tte->move() != MOVE_NONE + && move_is_legal(p, tte->move()) + && ply < PLY_MAX + && (!p.is_draw() || ply < 2)) + { + pv[ply] = tte->move(); + p.do_move(pv[ply++], st); + } + pv[ply] = MOVE_NONE; + } + + // init_thread() is the function which is called when a new thread is // launched. It simply calls the idle_loop() function with the supplied // threadID. There are two versions of this function; one for POSIX @@ -2427,8 +2451,8 @@ namespace { #endif // Initialize global locks - lock_init(&MPLock, NULL); - lock_init(&WaitLock, NULL); + lock_init(&MPLock); + lock_init(&WaitLock); #if !defined(_MSC_VER) pthread_cond_init(&WaitCond, NULL); @@ -2440,7 +2464,7 @@ namespace { // Initialize splitPoints[] locks for (i = 0; i < MAX_THREADS; i++) for (int j = 0; j < MAX_ACTIVE_SPLIT_POINTS; j++) - lock_init(&(threads[i].splitPoints[j].lock), NULL); + lock_init(&(threads[i].splitPoints[j].lock)); // Will be set just before program exits to properly end the threads AllThreadsShouldExit = false; @@ -2583,8 +2607,8 @@ namespace { template void ThreadsManager::split(const Position& p, SearchStack* ss, int ply, Value* alpha, - const Value beta, Value* bestValue, Depth depth, bool mateThreat, - int* moveCount, MovePicker* mp, bool pvNode) { + const Value beta, Value* bestValue, Depth depth, Move threatMove, + bool mateThreat, int* moveCount, MovePicker* mp, bool pvNode) { assert(p.is_ok()); assert(ply > 0 && ply < PLY_MAX); assert(*bestValue >= -VALUE_INFINITE); @@ -2617,6 +2641,7 @@ namespace { splitPoint.stopRequest = false; splitPoint.ply = ply; splitPoint.depth = depth; + splitPoint.threatMove = threatMove; splitPoint.mateThreat = mateThreat; splitPoint.alpha = *alpha; splitPoint.beta = beta; @@ -2731,6 +2756,11 @@ namespace { StateInfo st; bool includeAllMoves = (searchMoves[0] == MOVE_NONE); + // Initialize search stack + init_ss_array(ss, PLY_MAX_PLUS_2); + ss[0].currentMove = ss[0].bestMove = MOVE_NONE; + ss[0].eval = VALUE_NONE; + // Generate all legal moves MoveStack* last = generate_moves(pos, mlist); @@ -2746,10 +2776,8 @@ namespace { continue; // Find a quick score for the move - init_ss_array(ss, PLY_MAX_PLUS_2); - ss[0].eval = VALUE_NONE; - ss[0].currentMove = cur->move; pos.do_move(cur->move, st); + ss[0].currentMove = cur->move; moves[count].move = cur->move; moves[count].score = -qsearch(pos, ss+1, -VALUE_INFINITE, VALUE_INFINITE, Depth(0), 1); moves[count].pv[0] = cur->move;