X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=4eaf2e5ee07c2caea5ce159be013a68a6451d94c;hp=afdd204964b3272ba32f8b1653caa3c0c1bf93cc;hb=8737b26a23afb36d70cb32e3d53eeac7239685bf;hpb=972de506a03aeda06bab8b19771c71d37af99eb6 diff --git a/src/search.cpp b/src/search.cpp index afdd2049..4eaf2e5e 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -62,10 +62,6 @@ namespace { // Different node types, used as template parameter enum NodeType { Root, PV, NonPV, SplitPointRoot, SplitPointPV, SplitPointNonPV }; - // Lookup table to check if a Piece is a slider and its access function - const bool Slidings[18] = { 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 1 }; - inline bool piece_is_slider(Piece p) { return Slidings[p]; } - // Dynamic razoring margin based on depth inline Value razor_margin(Depth d) { return Value(512 + 16 * int(d)); } @@ -100,11 +96,10 @@ namespace { Value qsearch(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth); void id_loop(Position& pos); - bool check_is_dangerous(Position& pos, Move move, Value futilityBase, Value beta); - bool connected_moves(const Position& pos, Move m1, Move m2); Value value_to_tt(Value v, int ply); Value value_from_tt(Value v, int ply); - bool connected_threat(const Position& pos, Move m, Move threat); + bool check_is_dangerous(Position& pos, Move move, Value futilityBase, Value beta); + bool prevents_move(const Position& pos, Move first, Move second); string uci_pv(const Position& pos, int depth, Value alpha, Value beta); struct Skill { @@ -192,13 +187,13 @@ void Search::think() { { RootMoves.push_back(MOVE_NONE); sync_cout << "info depth 0 score " - << score_to_uci(RootPos.in_check() ? -VALUE_MATE : VALUE_DRAW) + << score_to_uci(RootPos.checkers() ? -VALUE_MATE : VALUE_DRAW) << sync_endl; goto finalize; } - if (Options["OwnBook"] && !Limits.infinite) + if (Options["OwnBook"] && !Limits.infinite && !Limits.mate) { Move bookMove = book.probe(RootPos, Options["Book File"], Options["Best Book Move"]); @@ -212,7 +207,7 @@ void Search::think() { if (Options["Contempt Factor"] && !Options["UCI_AnalyseMode"]) { int cf = Options["Contempt Factor"] * PawnValueMg / 100; // From centipawns - cf = cf * MaterialTable::game_phase(RootPos) / PHASE_MIDGAME; // Scale down with phase + cf = cf * Material::game_phase(RootPos) / PHASE_MIDGAME; // Scale down with phase DrawValue[ RootColor] = VALUE_DRAW - Value(cf); DrawValue[~RootColor] = VALUE_DRAW + Value(cf); } @@ -222,7 +217,7 @@ void Search::think() { if (Options["Use Search Log"]) { Log log(Options["Search Log Filename"]); - log << "\nSearching: " << RootPos.to_fen() + log << "\nSearching: " << RootPos.fen() << "\ninfinite: " << Limits.infinite << " ponder: " << Limits.ponder << " time: " << Limits.time[RootColor] @@ -231,22 +226,25 @@ void Search::think() { << std::endl; } - Threads.wake_up(); + // Reset the threads, still sleeping: will be wake up at split time + for (size_t i = 0; i < Threads.size(); i++) + Threads[i].maxPly = 0; + + Threads.sleepWhileIdle = Options["Use Sleeping Threads"]; // Set best timer interval to avoid lagging under time pressure. Timer is // used to check for remaining available thinking time. - if (Limits.use_time_management()) - Threads.set_timer(std::min(100, std::max(TimeMgr.available_time() / 16, - TimerResolution))); - else if (Limits.nodes) - Threads.set_timer(2 * TimerResolution); - else - Threads.set_timer(100); + Threads.timer_thread()->msec = + Limits.use_time_management() ? std::min(100, std::max(TimeMgr.available_time() / 16, TimerResolution)) : + Limits.nodes ? 2 * TimerResolution + : 100; + + Threads.timer_thread()->notify_one(); // Wake up the recurring timer id_loop(RootPos); // Let's start searching ! - Threads.set_timer(0); // Stop timer - Threads.sleep(); + Threads.timer_thread()->msec = 0; // Stop the timer + Threads.sleepWhileIdle = true; // Send idle threads to sleep if (Options["Use Search Log"]) { @@ -266,10 +264,15 @@ void Search::think() { finalize: // When we reach max depth we arrive here even without Signals.stop is raised, - // but if we are pondering or in infinite search, we shouldn't print the best - // move before we are told to do so. + // but if we are pondering or in infinite search, according to UCI protocol, + // we shouldn't print the best move before the GUI sends a "stop" or "ponderhit" + // command. We simply wait here until GUI sends one of those commands (that + // raise Signals.stop). if (!Signals.stop && (Limits.ponder || Limits.infinite)) - RootPos.this_thread()->wait_for_stop_or_ponderhit(); + { + Signals.stopOnPonderhit = true; + RootPos.this_thread()->wait_for(Signals.stop); + } // Best move could be MOVE_NONE when searching on a stalemate position sync_cout << "bestmove " << move_to_uci(RootMoves[0].pv[0], RootPos.is_chess960()) @@ -395,7 +398,8 @@ namespace { // Sort the PV lines searched so far and update the GUI sort(RootMoves.begin(), RootMoves.begin() + PVIdx + 1); - sync_cout << uci_pv(pos, depth, alpha, beta) << sync_endl; + if (PVIdx + 1 == PVSize || Time::now() - SearchTime > 3000) + sync_cout << uci_pv(pos, depth, alpha, beta) << sync_endl; } // Do we need to pick now the sub-optimal best move ? @@ -413,6 +417,12 @@ namespace { if (depth > 2 && BestMoveChanges) bestMoveNeverChanged = false; + // Do we have found a "mate in x"? + if ( Limits.mate + && bestValue >= VALUE_MATE_IN_MAX_PLY + && VALUE_MATE - bestValue <= 2 * Limits.mate) + Signals.stop = true; + // Do we have time for the next iteration? Can we stop searching now? if (Limits.use_time_management() && !Signals.stopOnPonderhit) { @@ -494,7 +504,7 @@ namespace { // Step 1. Initialize node Thread* thisThread = pos.this_thread(); moveCount = playedMoveCount = 0; - inCheck = pos.in_check(); + inCheck = pos.checkers(); if (SpNode) { @@ -580,15 +590,9 @@ namespace { else if (tte) { - // Following asserts are valid only in single thread condition because - // TT access is always racy and its contents cannot be trusted. - assert(tte->static_value() != VALUE_NONE || Threads.size() > 1); - assert(ttValue != VALUE_NONE || tte->type() == BOUND_NONE || Threads.size() > 1); - - ss->staticEval = eval = tte->static_value(); - ss->evalMargin = tte->static_value_margin(); - - if (eval == VALUE_NONE || ss->evalMargin == VALUE_NONE) // Due to a race + // Never assume anything on values stored in TT + if ( (ss->staticEval = eval = tte->static_value()) == VALUE_NONE + ||(ss->evalMargin = tte->static_value_margin()) == VALUE_NONE) eval = ss->staticEval = evaluate(pos, ss->evalMargin); // Can ttValue be used as a better position evaluation? @@ -688,21 +692,9 @@ namespace { return nullValue; } else - { // The null move failed low, which means that we may be faced with - // some kind of threat. If the previous move was reduced, check if - // the move that refuted the null move was somehow connected to the - // move which was reduced. If a connection is found, return a fail - // low score (which will cause the reduced move to fail high in the - // parent node, which will trigger a re-search with full depth). + // some kind of threat. threatMove = (ss+1)->currentMove; - - if ( depth < 5 * ONE_PLY - && (ss-1)->reduction - && threatMove != MOVE_NONE - && connected_moves(pos, (ss-1)->currentMove, threatMove)) - return beta - 1; - } } // Step 9. ProbCut (is omitted in PV nodes) @@ -797,7 +789,7 @@ split_point_start: // At split points actual search starts from here { Signals.firstRootMove = (moveCount == 1); - if (thisThread == Threads.main_thread() && Time::now() - SearchTime > 2000) + if (thisThread == Threads.main_thread() && Time::now() - SearchTime > 3000) sync_cout << "info depth " << depth / ONE_PLY << " currmove " << move_to_uci(move, pos.is_chess960()) << " currmovenumber " << moveCount + PVIdx << sync_endl; @@ -855,13 +847,12 @@ split_point_start: // At split points actual search starts from here && !inCheck && !dangerous && move != ttMove + && (!threatMove || !prevents_move(pos, move, threatMove)) && (bestValue > VALUE_MATED_IN_MAX_PLY || ( bestValue == -VALUE_INFINITE && alpha > VALUE_MATED_IN_MAX_PLY))) { // Move count based pruning - if ( depth < 16 * ONE_PLY - && moveCount >= FutilityMoveCounts[depth] - && (!threatMove || !connected_threat(pos, move, threatMove))) + if (depth < 16 * ONE_PLY && moveCount >= FutilityMoveCounts[depth]) { if (SpNode) sp->mutex.lock(); @@ -896,13 +887,13 @@ split_point_start: // At split points actual search starts from here } // Check for legality only before to do the move - if (!pos.pl_move_is_legal(move, ci.pinned)) + if (!RootNode && !SpNode && !pos.pl_move_is_legal(move, ci.pinned)) { moveCount--; continue; } - pvMove = PvNode ? moveCount == 1 : false; + pvMove = PvNode && moveCount == 1; ss->currentMove = move; if (!SpNode && !captureOrPromotion && playedMoveCount < 64) movesSearched[playedMoveCount++] = move; @@ -994,22 +985,21 @@ split_point_start: // At split points actual search starts from here if (value > bestValue) { - bestValue = value; - if (SpNode) sp->bestValue = value; + bestValue = SpNode ? sp->bestValue = value : value; if (value > alpha) { - bestMove = move; - if (SpNode) sp->bestMove = move; + bestMove = SpNode ? sp->bestMove = move : move; - if (PvNode && value < beta) - { - alpha = value; // Update alpha here! Always alpha < beta - if (SpNode) sp->alpha = value; - } - else // Fail high + if (PvNode && value < beta) // Update alpha! Always alpha < beta + alpha = SpNode ? sp->alpha = value : value; + else { - if (SpNode) sp->cutoff = true; + assert(value >= beta); // Fail high + + if (SpNode) + sp->cutoff = true; + break; } } @@ -1018,12 +1008,14 @@ split_point_start: // At split points actual search starts from here // Step 19. Check for splitting the search if ( !SpNode && depth >= Threads.min_split_depth() - && bestValue < beta && Threads.available_slave_exists(thisThread)) { + assert(bestValue < beta); + bestValue = Threads.split(pos, ss, alpha, beta, bestValue, &bestMove, depth, threatMove, moveCount, mp, NT); - break; + if (bestValue >= beta) + break; } } @@ -1095,7 +1087,7 @@ split_point_start: // At split points actual search starts from here const bool PvNode = (NT == PV); assert(NT == PV || NT == NonPV); - assert(InCheck == pos.in_check()); + assert(InCheck == !!pos.checkers()); assert(alpha >= -VALUE_INFINITE && alpha < beta && beta <= VALUE_INFINITE); assert(PvNode || (alpha == beta - 1)); assert(depth <= DEPTH_ZERO); @@ -1104,10 +1096,14 @@ split_point_start: // At split points actual search starts from here const TTEntry* tte; Key posKey; Move ttMove, move, bestMove; - Value bestValue, value, ttValue, futilityValue, futilityBase; + Value bestValue, value, ttValue, futilityValue, futilityBase, oldAlpha; bool givesCheck, enoughMaterial, evasionPrunable; Depth ttDepth; + // To flag BOUND_EXACT a node with eval above alpha and no available moves + if (PvNode) + oldAlpha = alpha; + ss->currentMove = bestMove = MOVE_NONE; ss->ply = (ss-1)->ply + 1; @@ -1149,12 +1145,9 @@ split_point_start: // At split points actual search starts from here { if (tte) { - assert(tte->static_value() != VALUE_NONE || Threads.size() > 1); - - ss->staticEval = bestValue = tte->static_value(); - ss->evalMargin = tte->static_value_margin(); - - if (ss->staticEval == VALUE_NONE || ss->evalMargin == VALUE_NONE) // Due to a race + // Never assume anything on values stored in TT + if ( (ss->staticEval = bestValue = tte->static_value()) == VALUE_NONE + ||(ss->evalMargin = tte->static_value_margin()) == VALUE_NONE) ss->staticEval = bestValue = evaluate(pos, ss->evalMargin); } else @@ -1206,9 +1199,7 @@ split_point_start: // At split points actual search starts from here if (futilityValue < beta) { - if (futilityValue > bestValue) - bestValue = futilityValue; - + bestValue = std::max(bestValue, futilityValue); continue; } @@ -1216,7 +1207,10 @@ split_point_start: // At split points actual search starts from here if ( futilityBase < beta && depth < DEPTH_ZERO && pos.see(move) <= 0) + { + bestValue = std::max(bestValue, futilityBase); continue; + } } // Detect non-capture evasions that are candidate to be pruned @@ -1287,7 +1281,7 @@ split_point_start: // At split points actual search starts from here return mated_in(ss->ply); // Plies to mate from the root TT.store(posKey, value_to_tt(bestValue, ss->ply), - PvNode && bestMove != MOVE_NONE ? BOUND_EXACT : BOUND_UPPER, + PvNode && bestValue > oldAlpha ? BOUND_EXACT : BOUND_UPPER, ttDepth, bestMove, ss->staticEval, ss->evalMargin); assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE); @@ -1357,91 +1351,50 @@ split_point_start: // At split points actual search starts from here } - // connected_moves() tests whether two moves are 'connected' in the sense - // that the first move somehow made the second move possible (for instance - // if the moving piece is the same in both moves). The first move is assumed - // to be the move that was made to reach the current position, while the - // second move is assumed to be a move from the current position. - - bool connected_moves(const Position& pos, Move m1, Move m2) { - - assert(is_ok(m1)); - assert(is_ok(m2)); - - Square t1 = to_sq(m1); - Square f1 = from_sq(m1); - Square t2 = to_sq(m2); - Square f2 = from_sq(m2); - - // The moving piece is the same or its destination square was vacated by m1 - if (t1 == f2 || t2 == f1) - return true; - - // Moving through the vacated square - if (between_bb(f2, t2) & f1) - return true; - - // The destination square for m2 is defended by the moving piece in m1 - Bitboard t1_att = pos.attacks_from(pos.piece_on(t1), t1, pos.pieces() ^ f2); - if (t1_att & t2) - return true; - - // Discovered check, checking piece is the piece moved in m1 - Square ksq = pos.king_square(pos.side_to_move()); - if ((t1_att & ksq) && (between_bb(t1, ksq) & f2)) - return true; - - return false; - } - - - // connected_threat() tests whether it is safe to forward prune a move or if - // is somehow connected to the threat move returned by null search. + // prevents_move() tests whether a move (first) is able to defend against an + // opponent's move (second). In this case will not be pruned. Normally the + // second move is the threat move (the best move returned from a null search + // that fails low). - bool connected_threat(const Position& pos, Move m, Move threat) { + bool prevents_move(const Position& pos, Move first, Move second) { - assert(is_ok(m)); - assert(is_ok(threat)); - assert(!pos.is_capture_or_promotion(m)); - assert(!pos.is_passed_pawn_push(m)); + assert(is_ok(first)); + assert(is_ok(second)); - Square mfrom = from_sq(m); - Square mto = to_sq(m); - Square tfrom = from_sq(threat); - Square tto = to_sq(threat); + Square m1from = from_sq(first); + Square m2from = from_sq(second); + Square m1to = to_sq(first); + Square m2to = to_sq(second); - // Case 1: Don't prune moves which move the threatened piece - if (mfrom == tto) + // Don't prune moves of the threatened piece + if (m1from == m2to) return true; - // Case 2: If the threatened piece has value less than or equal to the - // value of the threatening piece, don't prune moves which defend it. - if ( pos.is_capture(threat) - && ( PieceValue[MG][pos.piece_on(tfrom)] >= PieceValue[MG][pos.piece_on(tto)] - || type_of(pos.piece_on(tfrom)) == KING)) + // If the threatened piece has value less than or equal to the value of the + // threat piece, don't prune moves which defend it. + if ( pos.is_capture(second) + && ( PieceValue[MG][pos.piece_on(m2from)] >= PieceValue[MG][pos.piece_on(m2to)] + || type_of(pos.piece_on(m2from)) == KING)) { // Update occupancy as if the piece and the threat are moving - Bitboard occ = pos.pieces() ^ mfrom ^ mto ^ tfrom; - Piece piece = pos.piece_on(mfrom); + Bitboard occ = pos.pieces() ^ m1from ^ m1to ^ m2from; + Piece piece = pos.piece_on(m1from); // The moved piece attacks the square 'tto' ? - if (pos.attacks_from(piece, mto, occ) & tto) + if (pos.attacks_from(piece, m1to, occ) & m2to) return true; // Scan for possible X-ray attackers behind the moved piece - Bitboard xray = (attacks_bb< ROOK>(tto, occ) & pos.pieces(color_of(piece), QUEEN, ROOK)) - | (attacks_bb(tto, occ) & pos.pieces(color_of(piece), QUEEN, BISHOP)); + Bitboard xray = (attacks_bb< ROOK>(m2to, occ) & pos.pieces(color_of(piece), QUEEN, ROOK)) + | (attacks_bb(m2to, occ) & pos.pieces(color_of(piece), QUEEN, BISHOP)); // Verify attackers are triggered by our move and not already existing - if (xray && (xray ^ (xray & pos.attacks_from(tto)))) + if (xray && (xray ^ (xray & pos.attacks_from(m2to)))) return true; } - // Case 3: If the moving piece in the threatened move is a slider, don't - // prune safe moves which block its ray. - if ( piece_is_slider(pos.piece_on(tfrom)) - && (between_bb(tfrom, tto) & mto) - && pos.see_sign(m) >= 0) + // Don't prune safe moves which block the threat path + if ((between_bb(m2from, m2to) & m1to) && pos.see_sign(first) >= 0) return true; return false; @@ -1554,7 +1507,8 @@ void RootMove::extract_pv_from_tt(Position& pos) { do { pv.push_back(m); - assert(pos.move_is_legal(pv[ply])); + assert(MoveList(pos).contains(pv[ply])); + pos.do_move(pv[ply++], *st++); tte = TT.probe(pos.key()); @@ -1579,22 +1533,15 @@ void RootMove::insert_pv_in_tt(Position& pos) { StateInfo state[MAX_PLY_PLUS_2], *st = state; TTEntry* tte; int ply = 0; - Value v, m; do { tte = TT.probe(pos.key()); if (!tte || tte->move() != pv[ply]) // Don't overwrite correct entries - { - if (pos.in_check()) - v = m = VALUE_NONE; - else - v = evaluate(pos, m); + TT.store(pos.key(), VALUE_NONE, BOUND_NONE, DEPTH_NONE, pv[ply], VALUE_NONE, VALUE_NONE); - TT.store(pos.key(), VALUE_NONE, BOUND_NONE, DEPTH_NONE, pv[ply], v, m); - } + assert(MoveList(pos).contains(pv[ply])); - assert(pos.move_is_legal(pv[ply])); pos.do_move(pv[ply++], *st++); } while (pv[ply] != MOVE_NONE); @@ -1619,9 +1566,7 @@ void Thread::idle_loop() { { // If we are not searching, wait for a condition to be signaled // instead of wasting CPU time polling for work. - while ( do_sleep - || do_exit - || (!is_searching && Threads.use_sleeping_threads())) + while (do_exit || (!is_searching && Threads.sleepWhileIdle)) { if (do_exit) { @@ -1643,7 +1588,7 @@ void Thread::idle_loop() { // particular we need to avoid a deadlock in case a master thread has, // in the meanwhile, allocated us and sent the wake_up() call before we // had the chance to grab the lock. - if (do_sleep || !is_searching) + if (!is_searching && Threads.sleepWhileIdle) sleepCondition.wait(mutex); mutex.unlock(); @@ -1652,7 +1597,7 @@ void Thread::idle_loop() { // If this thread has been assigned work, launch a search if (is_searching) { - assert(!do_sleep && !do_exit); + assert(!do_exit); Threads.mutex.lock(); @@ -1691,12 +1636,12 @@ void Thread::idle_loop() { // Wake up master thread so to allow it to return from the idle loop in // case we are the last slave of the split point. - if ( Threads.use_sleeping_threads() + if ( Threads.sleepWhileIdle && this != sp->master && !sp->slavesMask) { assert(!sp->master->is_searching); - sp->master->wake_up(); + sp->master->notify_one(); } // After releasing the lock we cannot access anymore any SplitPoint