X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=3152260745f21b8cf2ed8af1ab5051825dc581c2;hp=edd23dad431f7de4037db2c9e8b8604616438022;hb=91a27663084ea9be4918ba028aa2b151bc0f4e1c;hpb=29076043e073c3d6e3b90b0809afc2a0af57e5e1 diff --git a/src/search.cpp b/src/search.cpp index edd23dad..31522607 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -129,7 +129,7 @@ namespace { void extract_pv_from_tt(Position& pos); void insert_pv_in_tt(Position& pos); - std::string pv_info_to_uci(Position& pos, Depth depth, Value alpha, Value beta, int pvLine = 0); + std::string pv_info_to_uci(Position& pos, int depth, Value alpha, Value beta, int pvLine); int64_t nodes; Value pv_score; @@ -209,10 +209,6 @@ namespace { // Minimum depth for use of singular extension const Depth SingularExtensionDepth[2] = { 8 * ONE_PLY /* non-PV */, 6 * ONE_PLY /* PV */}; - // If the TT move is at least SingularExtensionMargin better then the - // remaining ones we will extend it. - const Value SingularExtensionMargin = Value(0x20); - // Step 12. Futility pruning // Futility margin for quiescence search @@ -249,7 +245,7 @@ namespace { // MultiPV mode int MultiPV; - // Time managment variables + // Time management variables int SearchStartTime, MaxNodes, MaxDepth, ExactMaxTime; bool UseTimeManagement, InfiniteSearch, Pondering, StopOnPonderhit; bool FirstRootMove, StopRequest, QuitRequest, AspirationFailLow; @@ -306,7 +302,7 @@ namespace { int current_search_time(); std::string value_to_uci(Value v); - int nps(const Position& pos); + std::string speed_to_uci(int64_t nodes); void poll(const Position& pos); void wait_for_stop_or_ponderhit(); @@ -331,7 +327,7 @@ namespace { Value score = VALUE_ZERO; // Score root moves using the standard way used in main search, the moves - // are scored according to the order in which are returned by MovePicker. + // are scored according to the order in which they are returned by MovePicker. // This is the second order score that is used to compare the moves when // the first order pv scores of both moves are equal. while ((move = MovePicker::get_next_move()) != MOVE_NONE) @@ -544,12 +540,13 @@ bool think(Position& pos, bool infinite, bool ponder, int time[], int increment[ std::string name = Options["Search Log Filename"].value(); LogFile.open(name.c_str(), std::ios::out | std::ios::app); - LogFile << "Searching: " << pos.to_fen() - << "\ninfinite: " << infinite - << " ponder: " << ponder - << " time: " << myTime - << " increment: " << myIncrement - << " moves to go: " << movesToGo << endl; + LogFile << "\nSearching: " << pos.to_fen() + << "\ninfinite: " << infinite + << " ponder: " << ponder + << " time: " << myTime + << " increment: " << myIncrement + << " moves to go: " << movesToGo + << endl; } // We're ready to start thinking. Call the iterative deepening loop function @@ -557,25 +554,20 @@ bool think(Position& pos, bool infinite, bool ponder, int time[], int increment[ Move bestMove = id_loop(pos, searchMoves, &ponderMove); // Print final search statistics - cout << "info nodes " << pos.nodes_searched() - << " nps " << nps(pos) - << " time " << current_search_time() << endl; + cout << "info" << speed_to_uci(pos.nodes_searched()) << endl; if (UseLogFile) { - LogFile << "\nNodes: " << pos.nodes_searched() - << "\nNodes/second: " << nps(pos) - << "\nBest move: " << move_to_san(pos, bestMove); + int t = current_search_time(); + + LogFile << "Nodes: " << pos.nodes_searched() + << "\nNodes/second: " << (t > 0 ? int(pos.nodes_searched() * 1000 / t) : 0) + << "\nBest move: " << move_to_san(pos, bestMove); StateInfo st; pos.do_move(bestMove, st); - LogFile << "\nPonder move: " - << move_to_san(pos, ponderMove) // Works also with MOVE_NONE - << endl; - - // Return from think() with unchanged position - pos.undo_move(bestMove); - + LogFile << "\nPonder move: " << move_to_san(pos, ponderMove) << endl; + pos.undo_move(bestMove); // Return from think() with unchanged position LogFile.close(); } @@ -605,9 +597,8 @@ namespace { SearchStack ss[PLY_MAX_PLUS_2]; Value bestValues[PLY_MAX_PLUS_2]; int bestMoveChanges[PLY_MAX_PLUS_2]; - int iteration, researchCountFL, researchCountFH, aspirationDelta; + int depth, researchCountFL, researchCountFH, aspirationDelta; Value value, alpha, beta; - Depth depth; Move bestMove, easyMove; // Moves to search are verified, scored and sorted @@ -616,13 +607,13 @@ namespace { // Initialize FIXME move before Rml.init() TT.new_search(); H.clear(); - memset(ss, 0, PLY_MAX_PLUS_2 * sizeof(SearchStack)); + memset(ss, 0, 4 * sizeof(SearchStack)); *ponderMove = bestMove = easyMove = MOVE_NONE; - iteration = aspirationDelta = 0; + depth = aspirationDelta = 0; ss->currentMove = MOVE_NULL; // Hack to skip update_gains() alpha = -VALUE_INFINITE, beta = VALUE_INFINITE; - // Handle special case of searching on a mate/stale position + // Handle special case of searching on a mate/stalemate position if (Rml.size() == 0) { cout << "info depth 0 score " @@ -638,27 +629,22 @@ namespace { easyMove = Rml[0].pv[0]; // Iterative deepening loop - while (++iteration <= PLY_MAX && !StopRequest) + while (++depth <= PLY_MAX && (!MaxDepth || depth <= MaxDepth) && !StopRequest) { Rml.bestMoveChanges = researchCountFL = researchCountFH = 0; - depth = iteration * ONE_PLY; - - if (MaxDepth && depth > MaxDepth * ONE_PLY) - break; - - cout << "info depth " << depth / ONE_PLY << endl; + cout << "info depth " << depth << endl; // Calculate dynamic aspiration window based on previous iterations - if (MultiPV == 1 && iteration >= 5 && abs(bestValues[iteration - 1]) < VALUE_KNOWN_WIN) + if (MultiPV == 1 && depth >= 5 && abs(bestValues[depth - 1]) < VALUE_KNOWN_WIN) { - int prevDelta1 = bestValues[iteration - 1] - bestValues[iteration - 2]; - int prevDelta2 = bestValues[iteration - 2] - bestValues[iteration - 3]; + int prevDelta1 = bestValues[depth - 1] - bestValues[depth - 2]; + int prevDelta2 = bestValues[depth - 2] - bestValues[depth - 3]; aspirationDelta = Min(Max(abs(prevDelta1) + abs(prevDelta2) / 2, 16), 24); aspirationDelta = (aspirationDelta + 7) / 8 * 8; // Round to match grainSize - alpha = Max(bestValues[iteration - 1] - aspirationDelta, -VALUE_INFINITE); - beta = Min(bestValues[iteration - 1] + aspirationDelta, VALUE_INFINITE); + alpha = Max(bestValues[depth - 1] - aspirationDelta, -VALUE_INFINITE); + beta = Min(bestValues[depth - 1] + aspirationDelta, VALUE_INFINITE); } // Start with a small aspiration window and, in case of fail high/low, @@ -666,7 +652,7 @@ namespace { while (true) { // Search starting from ss+1 to allow calling update_gains() - value = search(pos, ss+1, alpha, beta, depth, 0); + value = search(pos, ss+1, alpha, beta, depth * ONE_PLY, 0); // Send PV line to GUI and write to transposition table in case the // relevant entries have been overwritten during the search. @@ -704,8 +690,11 @@ namespace { // Collect info about search result bestMove = Rml[0].pv[0]; - bestValues[iteration] = value; - bestMoveChanges[iteration] = Rml.bestMoveChanges; + bestValues[depth] = value; + bestMoveChanges[depth] = Rml.bestMoveChanges; + + if (UseLogFile) + LogFile << pretty_pv(pos, depth, value, current_search_time(), Rml[0].pv) << endl; // Drop the easy move if differs from the new best move if (bestMove != easyMove) @@ -717,15 +706,15 @@ namespace { bool noMoreTime = false; // Stop search early when the last two iterations returned a mate score - if ( iteration >= 5 - && abs(bestValues[iteration]) >= abs(VALUE_MATE) - 100 - && abs(bestValues[iteration - 1]) >= abs(VALUE_MATE) - 100) + if ( depth >= 5 + && abs(bestValues[depth]) >= abs(VALUE_MATE) - 100 + && abs(bestValues[depth - 1]) >= abs(VALUE_MATE) - 100) noMoreTime = true; // Stop search early if one move seems to be much better than the // others or if there is only a single legal move. In this latter // case we search up to Iteration 8 anyway to get a proper score. - if ( iteration >= 7 + if ( depth >= 7 && easyMove == bestMove && ( Rml.size() == 1 ||( Rml[0].nodes > (pos.nodes_searched() * 85) / 100 @@ -735,8 +724,8 @@ namespace { noMoreTime = true; // Add some extra time if the best move has changed during the last two iterations - if (iteration > 4 && iteration < 50) - TimeMgr.pv_instability(bestMoveChanges[iteration], bestMoveChanges[iteration-1]); + if (depth > 4 && depth < 50) + TimeMgr.pv_instability(bestMoveChanges[depth], bestMoveChanges[depth-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 @@ -808,7 +797,8 @@ namespace { bestValue = alpha; // Step 1. Initialize node and poll. Polling can abort search - ss->currentMove = ss->bestMove = threatMove = MOVE_NONE; + ss->currentMove = ss->bestMove = threatMove = (ss+1)->excludedMove = MOVE_NONE; + (ss+1)->skipNullMove = false; (ss+1)->reduction = DEPTH_ZERO; (ss+2)->killers[0] = (ss+2)->killers[1] = (ss+2)->mateKiller = MOVE_NONE; if (threadID == 0 && ++NodesSincePoll > NodesBetweenPolls) @@ -832,7 +822,7 @@ namespace { // Step 4. Transposition table lookup // We don't want the score of a partial search to overwrite a previous full search - // TT value, so we use a different position key in case of an excluded move exists. + // TT value, so we use a different position key in case of an excluded move. excludedMove = ss->excludedMove; posKey = excludedMove ? pos.get_exclusion_key() : pos.get_key(); @@ -1034,9 +1024,7 @@ split_point_start: // At split points actual search starts from here if (SendSearchedNodes) { SendSearchedNodes = false; - cout << "info nodes " << nodes - << " nps " << nps(pos) - << " time " << current_search_time() << endl; + cout << "info" << speed_to_uci(pos.nodes_searched()) << endl; } if (current_search_time() >= 1000) @@ -1054,7 +1042,7 @@ split_point_start: // At split points actual search starts from here // Singular extension search. If all moves but one fail low on a search of (alpha-s, beta-s), // and just one fails high on (alpha, beta), then that move is singular and should be extended. // To verify this we do a reduced search on all the other moves but the ttMove, if result is - // lower then ttValue minus a margin then we extend ttMove. + // lower than ttValue minus a margin then we extend ttMove. if ( singularExtensionNode && move == tte->move() && ext < ONE_PLY) @@ -1063,7 +1051,7 @@ split_point_start: // At split points actual search starts from here if (abs(ttValue) < VALUE_KNOWN_WIN) { - Value b = ttValue - SingularExtensionMargin; + Value b = ttValue - depth; ss->excludedMove = move; ss->skipNullMove = true; Value v = search(pos, ss, b - 1, b, depth / 2, ply); @@ -1077,7 +1065,7 @@ split_point_start: // At split points actual search starts from here // Update current move (this must be done after singular extension search) ss->currentMove = move; - newDepth = depth - (!Root ? ONE_PLY : DEPTH_ZERO) + ext; + newDepth = depth - ONE_PLY + ext; // Step 12. Futility pruning (is omitted in PV nodes) if ( !PvNode @@ -1160,8 +1148,7 @@ split_point_start: // At split points actual search starts from here && ss->killers[0] != move && ss->killers[1] != move) { - ss->reduction = Root ? reduction(depth, moveCount - MultiPV + 1) - : reduction(depth, moveCount); + ss->reduction = reduction(depth, moveCount); if (ss->reduction) { alpha = SpNode ? sp->alpha : alpha; @@ -1200,14 +1187,14 @@ split_point_start: // At split points actual search starts from here alpha = sp->alpha; } - if (!Root && value > bestValue && !(SpNode && ThreadsMgr.cutoff_at_splitpoint(threadID))) + if (value > bestValue && !(SpNode && ThreadsMgr.cutoff_at_splitpoint(threadID))) { bestValue = value; if (SpNode) sp->bestValue = value; - if (value > alpha) + if (!Root && value > alpha) { if (PvNode && value < beta) // We want always alpha < beta { @@ -1225,16 +1212,12 @@ split_point_start: // At split points actual search starts from here ss->bestMove = move; if (SpNode) - sp->parentSstack->bestMove = move; + sp->ss->bestMove = move; } } if (Root) { - // To avoid to exit with bestValue == -VALUE_INFINITE - if (value > bestValue) - bestValue = value; - // Finished searching the move. If StopRequest is true, the search // 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 @@ -1246,20 +1229,16 @@ split_point_start: // At split points actual search starts from here // Remember searched nodes counts for this move mp.rm->nodes += pos.nodes_searched() - nodes; - // Step 17. Check for new best move - if (!isPvMove && value <= alpha) - mp.rm->pv_score = -VALUE_INFINITE; - else + // PV move or new best move ? + if (isPvMove || value > alpha) { - // PV move or new best move! - // Update PV ss->bestMove = move; mp.rm->pv_score = value; mp.rm->extract_pv_from_tt(pos); // We record how often the best move has been changed in each - // iteration. This information is used for time managment: When + // iteration. This information is used for time management: When // the best move changes frequently, we allocate some more time. if (!isPvMove && MultiPV == 1) Rml.bestMoveChanges++; @@ -1272,9 +1251,11 @@ split_point_start: // At split points actual search starts from here alpha = Rml[Min(moveCount, MultiPV) - 1].pv_score; // FIXME why moveCount? else if (value > alpha) alpha = value; + } + else + mp.rm->pv_score = -VALUE_INFINITE; - } // PV move or new best move - } + } // Root // Step 18. Check for split if ( !Root @@ -1446,6 +1427,13 @@ split_point_start: // At split points actual search starts from here bestValue = futilityValue; continue; } + + // Prune moves with negative or equal SEE + if ( futilityBase < beta + && depth < DEPTH_ZERO + && bestValue > value_mated_in(PLY_MAX) + && pos.see(move) <= 0) + continue; } // Detect non-capture evasions that are candidate to be pruned @@ -1751,7 +1739,7 @@ split_point_start: // At split points actual search starts from here // connected_threat() tests whether it is safe to forward prune a move or if - // is somehow coonected to the threat move returned by null search. + // is somehow connected to the threat move returned by null search. bool connected_threat(const Position& pos, Move m, Move threat) { @@ -1773,7 +1761,7 @@ split_point_start: // At split points actual search starts from here return true; // Case 2: If the threatened piece has value less than or equal to the - // value of the threatening piece, don't prune move which defend it. + // value of the threatening piece, don't prune moves which defend it. if ( pos.move_is_capture(threat) && ( pos.midgame_value_of_piece_on(tfrom) >= pos.midgame_value_of_piece_on(tto) || pos.type_of_piece_on(tfrom) == KING) @@ -1871,6 +1859,14 @@ split_point_start: // At split points actual search starts from here H.update_gain(pos.piece_on(move_to(m)), move_to(m), -(before + after)); } + // current_search_time() returns the number of milliseconds which have passed + // since the beginning of the current search. + + int current_search_time() { + + return get_system_time() - SearchStartTime; + } + // value_to_uci() converts a value to a string suitable for use with the UCI // protocol specifications: @@ -1886,27 +1882,25 @@ split_point_start: // At split points actual search starts from here if (abs(v) < VALUE_MATE - PLY_MAX * ONE_PLY) s << "cp " << int(v) * 100 / int(PawnValueMidgame); // Scale to centipawns else - s << "mate " << (v > 0 ? (VALUE_MATE - v + 1) / 2 : -(VALUE_MATE + v) / 2 ); + s << "mate " << (v > 0 ? (VALUE_MATE - v + 1) / 2 : -(VALUE_MATE + v) / 2); return s.str(); } - // current_search_time() returns the number of milliseconds which have passed - // since the beginning of the current search. + // speed_to_uci() returns a string with time stats of current search suitable + // to be sent to UCI gui. - int current_search_time() { + std::string speed_to_uci(int64_t nodes) { - return get_system_time() - SearchStartTime; - } - - - // nps() computes the current nodes/second count + std::stringstream s; + int t = current_search_time(); - int nps(const Position& pos) { + s << " nodes " << nodes + << " nps " << (t > 0 ? int(nodes * 1000 / t) : 0) + << " time " << t; - int t = current_search_time(); - return (t > 0 ? int((pos.nodes_searched() * 1000) / t) : 0); + return s.str(); } @@ -2123,16 +2117,19 @@ split_point_start: // At split points actual search starts from here threads[threadID].state = THREAD_SEARCHING; - // Here we call search() with SplitPoint template parameter set to true + // Copy SplitPoint position and search stack and call search() + // with SplitPoint template parameter set to true. + SearchStack ss[PLY_MAX_PLUS_2]; SplitPoint* tsp = threads[threadID].splitPoint; Position pos(*tsp->pos, threadID); - SearchStack* ss = tsp->sstack[threadID] + 1; - ss->sp = tsp; + + memcpy(ss, tsp->ss - 1, 4 * sizeof(SearchStack)); + (ss+1)->sp = tsp; if (tsp->pvNode) - search(pos, ss, tsp->alpha, tsp->beta, tsp->depth, tsp->ply); + search(pos, ss+1, tsp->alpha, tsp->beta, tsp->depth, tsp->ply); else - search(pos, ss, tsp->alpha, tsp->beta, tsp->depth, tsp->ply); + search(pos, ss+1, tsp->alpha, tsp->beta, tsp->depth, tsp->ply); assert(threads[threadID].state == THREAD_SEARCHING); @@ -2377,7 +2374,7 @@ split_point_start: // At split points actual search starts from here splitPoint.moveCount = moveCount; splitPoint.pos = &pos; splitPoint.nodes = 0; - splitPoint.parentSstack = ss; + splitPoint.ss = ss; for (i = 0; i < activeThreads; i++) splitPoint.slaves[i] = 0; @@ -2404,12 +2401,10 @@ split_point_start: // At split points actual search starts from here lock_release(&mpLock); // Tell the threads that they have work to do. This will make them leave - // their idle loop. But before copy search stack tail for each thread. + // their idle loop. for (i = 0; i < activeThreads; i++) if (i == master || splitPoint.slaves[i]) { - memcpy(splitPoint.sstack[i], ss - 1, 4 * sizeof(SearchStack)); - assert(i == master || threads[i].state == THREAD_BOOKED); threads[i].state = THREAD_WORKISWAITING; // This makes the slave to exit from idle_loop() @@ -2520,7 +2515,7 @@ split_point_start: // At split points actual search starts from here k = pos.get_key(); tte = TT.retrieve(k); - // Don't overwrite exsisting correct entries + // Don't overwrite existing correct entries if (!tte || tte->move() != pv[ply]) { v = (pos.is_check() ? VALUE_NONE : evaluate(pos, m)); @@ -2534,10 +2529,10 @@ split_point_start: // At split points actual search starts from here } // pv_info_to_uci() returns a string with information on the current PV line - // formatted according to UCI specification and eventually writes the info - // to a log file. It is called at each iteration or after a new pv is found. + // formatted according to UCI specification. It is called at each iteration + // or after a new pv is found. - std::string RootMove::pv_info_to_uci(Position& pos, Depth depth, Value alpha, Value beta, int pvLine) { + std::string RootMove::pv_info_to_uci(Position& pos, int depth, Value alpha, Value beta, int pvLine) { std::stringstream s, l; Move* m = pv; @@ -2545,23 +2540,14 @@ split_point_start: // At split points actual search starts from here while (*m != MOVE_NONE) l << *m++ << " "; - s << "info depth " << depth / ONE_PLY + s << "info depth " << depth << " seldepth " << int(m - pv) << " multipv " << pvLine + 1 << " score " << value_to_uci(pv_score) << (pv_score >= beta ? " lowerbound" : pv_score <= alpha ? " upperbound" : "") - << " time " << current_search_time() - << " nodes " << pos.nodes_searched() - << " nps " << nps(pos) + << speed_to_uci(pos.nodes_searched()) << " pv " << l.str(); - if (UseLogFile && pvLine == 0) - { - ValueType t = pv_score >= beta ? VALUE_TYPE_LOWER : - pv_score <= alpha ? VALUE_TYPE_UPPER : VALUE_TYPE_EXACT; - - LogFile << pretty_pv(pos, current_search_time(), depth / ONE_PLY, pv_score, t, pv) << endl; - } return s.str(); }