X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=d47fab1fea3564f3c944717b9c26295f2d9653bb;hp=8cdd7a21323033bd46706ef5264bb1911eb4a385;hb=876ceb1feb466f4dd2e29d01433878b8cf29cd6f;hpb=6849f0800e82845271ad5888600c141857e744ec diff --git a/src/search.cpp b/src/search.cpp index 8cdd7a21..d47fab1f 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 = 0); int64_t nodes; Value pv_score; @@ -203,8 +203,8 @@ namespace { // Extensions. Configurable UCI options // Array index 0 is used at non-PV nodes, index 1 at PV nodes. - Depth CheckExtension[2], SingleEvasionExtension[2], PawnPushTo7thExtension[2]; - Depth PassedPawnExtension[2], PawnEndgameExtension[2], MateThreatExtension[2]; + Depth CheckExtension[2], PawnPushTo7thExtension[2], PassedPawnExtension[2]; + Depth PawnEndgameExtension[2], MateThreatExtension[2]; // Minimum depth for use of singular extension const Depth SingularExtensionDepth[2] = { 8 * ONE_PLY /* non-PV */, 6 * ONE_PLY /* PV */}; @@ -289,7 +289,7 @@ namespace { } template - Depth extension(const Position& pos, Move m, bool captureOrPromotion, bool moveIsCheck, bool singleEvasion, bool mateThreat, bool* dangerous); + Depth extension(const Position& pos, Move m, bool captureOrPromotion, bool moveIsCheck, bool mateThreat, bool* dangerous); bool check_is_dangerous(Position &pos, Move move, Value futilityBase, Value beta, Value *bValue); bool connected_moves(const Position& pos, Move m1, Move m2); @@ -302,6 +302,7 @@ namespace { void update_history(const Position& pos, Move move, Depth depth, Move movesSearched[], int moveCount); void update_killers(Move m, Move killers[]); void update_gains(const Position& pos, Move move, Value before, Value after); + void qsearch_scoring(Position& pos, MoveStack* mlist, MoveStack* last); int current_search_time(); std::string value_to_uci(Value v); @@ -354,7 +355,6 @@ namespace { return rm != Rml.end() ? rm->pv[0] : MOVE_NONE; } - int number_of_evasions() const { return (int)Rml.size(); } RootMoveList::iterator rm; bool firstCall; @@ -500,8 +500,6 @@ bool think(Position& pos, bool infinite, bool ponder, int time[], int increment[ CheckExtension[1] = Options["Check Extension (PV nodes)"].value(); CheckExtension[0] = Options["Check Extension (non-PV nodes)"].value(); - SingleEvasionExtension[1] = Options["Single Evasion Extension (PV nodes)"].value(); - SingleEvasionExtension[0] = Options["Single Evasion Extension (non-PV nodes)"].value(); PawnPushTo7thExtension[1] = Options["Pawn Push to 7th Extension (PV nodes)"].value(); PawnPushTo7thExtension[0] = Options["Pawn Push to 7th Extension (non-PV nodes)"].value(); PassedPawnExtension[1] = Options["Passed Pawn Extension (PV nodes)"].value(); @@ -607,9 +605,8 @@ 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 @@ -619,51 +616,43 @@ namespace { TT.new_search(); H.clear(); memset(ss, 0, PLY_MAX_PLUS_2 * sizeof(SearchStack)); - alpha = -VALUE_INFINITE, beta = VALUE_INFINITE; *ponderMove = bestMove = easyMove = MOVE_NONE; - aspirationDelta = 0; - iteration = 1; + 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 if (Rml.size() == 0) { - cout << "info depth " << iteration << " score " + cout << "info depth 0 score " << value_to_uci(pos.is_check() ? -VALUE_MATE : VALUE_DRAW) << endl; return MOVE_NONE; } - // Send initial scoring (iteration 1) - cout << set960(pos.is_chess960()) // Is enough to set once at the beginning - << "info depth " << iteration - << "\n" << Rml[0].pv_info_to_uci(pos, ONE_PLY, alpha, beta) << endl; - // Is one move significantly better than others after initial scoring ? if ( Rml.size() == 1 || Rml[0].pv_score > Rml[1].pv_score + EasyMoveMargin) easyMove = Rml[0].pv[0]; // Iterative deepening loop - while (++iteration <= PLY_MAX && (!MaxDepth || iteration <= MaxDepth) && !StopRequest) + while (++depth <= PLY_MAX && (!MaxDepth || depth <= MaxDepth) && !StopRequest) { - cout << "info depth " << iteration << endl; - Rml.bestMoveChanges = researchCountFL = researchCountFH = 0; - depth = (iteration - 1) * ONE_PLY; + cout << "info depth " << depth << endl; // Calculate dynamic aspiration window based on previous iterations - if (MultiPV == 1 && iteration >= 6 && 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 = Max(abs(prevDelta1) + abs(prevDelta2) / 2, 16); + 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, @@ -671,12 +660,16 @@ 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); - // Write PV lines to transposition table, in case the relevant entries - // have been overwritten during the search. + // Send PV line to GUI and write to transposition table in case the + // relevant entries have been overwritten during the search. for (int i = 0; i < Min(MultiPV, (int)Rml.size()); i++) + { Rml[i].insert_pv_in_tt(pos); + cout << set960(pos.is_chess960()) + << Rml[i].pv_info_to_uci(pos, depth, alpha, beta, i) << endl; + } // Value cannot be trusted. Break out immediately! if (StopRequest) @@ -705,8 +698,8 @@ 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; // Drop the easy move if differs from the new best move if (bestMove != easyMove) @@ -718,15 +711,15 @@ namespace { bool noMoreTime = false; // Stop search early when the last two iterations returned a mate score - if ( iteration >= 6 - && 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 >= 8 + if ( depth >= 7 && easyMove == bestMove && ( Rml.size() == 1 ||( Rml[0].nodes > (pos.nodes_searched() * 85) / 100 @@ -736,8 +729,8 @@ namespace { noMoreTime = true; // Add some extra time if the best move has changed during the last two iterations - if (iteration > 5 && 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 @@ -786,7 +779,7 @@ namespace { ValueType vt; Value bestValue, value, oldAlpha; Value refinedValue, nullValue, futilityBase, futilityValueScaled; // Non-PV specific - bool isPvMove, isCheck, singleEvasion, singularExtensionNode, moveIsCheck, captureOrPromotion, dangerous; + bool isPvMove, isCheck, singularExtensionNode, moveIsCheck, captureOrPromotion, dangerous; bool mateThreat = false; int moveCount = 0, playedMoveCount = 0; int threadID = pos.thread(); @@ -840,14 +833,13 @@ namespace { tte = TT.retrieve(posKey); ttMove = tte ? tte->move() : MOVE_NONE; - // At PV nodes, we don't use the TT for pruning, but only for move ordering. - // This is to avoid problems in the following areas: - // - // * Repetition draw detection - // * Fifty move rule detection - // * Searching for a mate - // * Printing of full PV line - if (!PvNode && tte && ok_to_use_TT(tte, depth, beta, ply)) + // At PV nodes we check for exact scores, while at non-PV nodes we check for + // and return a fail high/low. Biggest advantage at probing at PV nodes is + // to have a smooth experience in analysis mode. + if ( !Root + && tte + && (PvNode ? tte->depth() >= depth && tte->type() == VALUE_TYPE_EXACT + : ok_to_use_TT(tte, depth, beta, ply))) { TT.refresh(tte); ss->bestMove = ttMove; // Can be MOVE_NONE @@ -990,7 +982,6 @@ split_point_start: // At split points actual search starts from here MovePickerExt mp(pos, ttMove, depth, H, ss, (PvNode ? -VALUE_INFINITE : beta)); CheckInfo ci(pos); ss->bestMove = MOVE_NONE; - singleEvasion = !SpNode && isCheck && mp.number_of_evasions() == 1; futilityBase = ss->eval + ss->evalMargin; singularExtensionNode = !Root && !SpNode @@ -1052,7 +1043,7 @@ split_point_start: // At split points actual search starts from here captureOrPromotion = pos.move_is_capture_or_promotion(move); // Step 11. Decide the new search depth - ext = extension(pos, move, captureOrPromotion, moveIsCheck, singleEvasion, mateThreat, &dangerous); + ext = extension(pos, move, captureOrPromotion, moveIsCheck, mateThreat, &dangerous); // 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. @@ -1267,13 +1258,8 @@ split_point_start: // At split points actual search starts from here if (!isPvMove && MultiPV == 1) Rml.bestMoveChanges++; - // Inform GUI that PV has changed, in case of multi-pv UCI protocol - // requires we send all the PV lines properly sorted. Rml.sort_multipv(moveCount); - for (int j = 0; j < Min(MultiPV, (int)Rml.size()); j++) - cout << Rml[j].pv_info_to_uci(pos, depth, alpha, beta, j) << endl; - // Update alpha. In multi-pv we don't use aspiration window, so // set alpha equal to minimum score among the PV lines. if (MultiPV > 1) @@ -1522,6 +1508,26 @@ split_point_start: // At split points actual search starts from here } + // qsearch_scoring() scores each move of a list using a qsearch() evaluation, + // it is used in RootMoveList to get an initial scoring. + void qsearch_scoring(Position& pos, MoveStack* mlist, MoveStack* last) { + + SearchStack ss[PLY_MAX_PLUS_2]; + StateInfo st; + + memset(ss, 0, 4 * sizeof(SearchStack)); + ss[0].eval = ss[0].evalMargin = VALUE_NONE; + + for (MoveStack* cur = mlist; cur != last; cur++) + { + ss[0].currentMove = cur->move; + pos.do_move(cur->move, st); + cur->score = -qsearch(pos, ss+1, -VALUE_INFINITE, VALUE_INFINITE, DEPTH_ZERO, 1); + pos.undo_move(cur->move); + } + } + + // check_is_dangerous() tests if a checking move can be pruned in qsearch(). // bestValue is updated only when returning false because in that case move // will be pruned. @@ -1682,22 +1688,19 @@ split_point_start: // At split points actual search starts from here // extended, as example because the corresponding UCI option is set to zero, // the move is marked as 'dangerous' so, at least, we avoid to prune it. template - Depth extension(const Position& pos, Move m, bool captureOrPromotion, bool moveIsCheck, - bool singleEvasion, bool mateThreat, bool* dangerous) { + Depth extension(const Position& pos, Move m, bool captureOrPromotion, + bool moveIsCheck, bool mateThreat, bool* dangerous) { assert(m != MOVE_NONE); Depth result = DEPTH_ZERO; - *dangerous = moveIsCheck | singleEvasion | mateThreat; + *dangerous = moveIsCheck | mateThreat; if (*dangerous) { if (moveIsCheck && pos.see_sign(m) >= 0) result += CheckExtension[PvNode]; - if (singleEvasion) - result += SingleEvasionExtension[PvNode]; - if (mateThreat) result += MateThreatExtension[PvNode]; } @@ -2528,7 +2531,7 @@ split_point_start: // At split points actual search starts from here // 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. - 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; @@ -2536,7 +2539,7 @@ 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) @@ -2551,7 +2554,7 @@ split_point_start: // At split points actual search starts from here 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; + LogFile << pretty_pv(pos, current_search_time(), depth, pv_score, t, pv) << endl; } return s.str(); } @@ -2559,19 +2562,15 @@ split_point_start: // At split points actual search starts from here void RootMoveList::init(Position& pos, Move searchMoves[]) { - SearchStack ss[PLY_MAX_PLUS_2]; MoveStack mlist[MOVES_MAX]; - StateInfo st; Move* sm; - // Initialize search stack - memset(ss, 0, PLY_MAX_PLUS_2 * sizeof(SearchStack)); - ss[0].eval = ss[0].evalMargin = VALUE_NONE; - bestMoveChanges = 0; clear(); + bestMoveChanges = 0; - // Generate all legal moves + // Generate all legal moves and score them MoveStack* last = generate(pos, mlist); + qsearch_scoring(pos, mlist, last); // Add each move to the RootMoveList's vector for (MoveStack* cur = mlist; cur != last; cur++) @@ -2583,16 +2582,11 @@ split_point_start: // At split points actual search starts from here if (searchMoves[0] && *sm != cur->move) continue; - // Find a quick score for the move and add to the list - pos.do_move(cur->move, st); - RootMove rm; - rm.pv[0] = ss[0].currentMove = cur->move; + rm.pv[0] = cur->move; rm.pv[1] = MOVE_NONE; - rm.pv_score = -qsearch(pos, ss+1, -VALUE_INFINITE, VALUE_INFINITE, DEPTH_ZERO, 1); + rm.pv_score = Value(cur->score); push_back(rm); - - pos.undo_move(cur->move); } sort(); }