X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=d02035183b07a262abd14de260b6baee824aa332;hp=aaed54ce1332e36dd16334d91bf2a87b3d5397c2;hb=d95b9189d850da83066a9bf3b2a1caffabb8073a;hpb=2e778445d5bcaa980bc0e34dfff797c006fd5f5b diff --git a/src/search.cpp b/src/search.cpp index aaed54ce..d0203518 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -188,7 +188,7 @@ namespace { // Time managment variables int SearchStartTime; int MaxNodes, MaxDepth; - int MaxSearchTime, AbsoluteMaxSearchTime, ExtraSearchTime, TimeAdvantage; + int MaxSearchTime, AbsoluteMaxSearchTime, ExtraSearchTime; Move BestRootMove, PonderMove, EasyMove; int RootMoveNumber; bool InfiniteSearch; @@ -238,19 +238,20 @@ namespace { Depth depth, int ply, int threadID); void sp_search(SplitPoint *sp, int threadID); void sp_search_pv(SplitPoint *sp, int threadID); - void init_search_stack(SearchStack ss); + void init_search_stack(SearchStack& ss); void init_search_stack(SearchStack ss[]); void init_node(const Position &pos, SearchStack ss[], int ply, int threadID); void update_pv(SearchStack ss[], int ply); void sp_update_pv(SearchStack *pss, SearchStack ss[], int ply); bool connected_moves(const Position &pos, Move m1, Move m2); bool move_is_killer(Move m, const SearchStack& ss); - Depth extension(const Position &pos, Move m, bool pvNode, bool check, bool singleReply, bool mateThreat); + Depth extension(const Position &pos, Move m, bool pvNode, bool check, bool singleReply, bool mateThreat, bool* dangerous); bool ok_to_do_nullmove(const Position &pos); bool ok_to_prune(const Position &pos, Move m, Move threat, Depth d); bool ok_to_use_TT(const TTEntry* tte, Depth depth, Value beta, int ply); bool ok_to_history(const Position &pos, Move m); void update_history(const Position& pos, Move m, Depth depth, Move movesSearched[], int moveCount); + void update_killers(Move m, SearchStack& ss); bool fail_high_ply_1(); int current_search_time(); @@ -426,16 +427,14 @@ void think(const Position &pos, bool infinite, bool ponder, int side_to_move, int myIncrement = increment[side_to_move]; int oppTime = time[1 - side_to_move]; - TimeAdvantage = myTime - oppTime; - if (!movesToGo) // Sudden death time control - { - if (increment) + { + if (myIncrement) { MaxSearchTime = myTime / 30 + myIncrement; AbsoluteMaxSearchTime = Max(myTime / 4, myIncrement - 100); } else { // Blitz game without increment - MaxSearchTime = myTime / 40; + MaxSearchTime = myTime / 30; AbsoluteMaxSearchTime = myTime / 8; } } @@ -679,10 +678,6 @@ namespace { ExtraSearchTime = BestMoveChangesByIteration[Iteration] * (MaxSearchTime / 2) + BestMoveChangesByIteration[Iteration-1] * (MaxSearchTime / 3); - // If we need some more and we are in time advantage take it - if (ExtraSearchTime > 0 && TimeAdvantage > 2 * MaxSearchTime) - ExtraSearchTime += MaxSearchTime / 2; - // Try to guess if the current iteration is the last one or the last two LastIterations = (current_search_time() > ((MaxSearchTime + ExtraSearchTime)*58) / 128); @@ -777,7 +772,8 @@ namespace { << " currmovenumber " << i + 1 << std::endl; // Decide search depth for this move - ext = extension(pos, move, true, pos.move_is_check(move), false, false); + bool dangerous; + ext = extension(pos, move, true, pos.move_is_check(move), false, false, &dangerous); newDepth = (Iteration - 2) * OnePly + ext + InitialDepth; // Make the move, and search it @@ -794,7 +790,7 @@ namespace { if (Problem && StopOnPonderhit) StopOnPonderhit = false; - } + } else { value = -search(pos, ss, -alpha, newDepth, 1, true, 0); @@ -951,8 +947,7 @@ namespace { Value value, bestValue = -VALUE_INFINITE; Bitboard dcCandidates = mp.discovered_check_candidates(); bool isCheck = pos.is_check(); - bool mateThreat = MateThreatExtension[1] > Depth(0) - && pos.has_mate_threat(opposite_color(pos.side_to_move())); + bool mateThreat = pos.has_mate_threat(opposite_color(pos.side_to_move())); // Loop through all legal moves until no moves remain or a beta cutoff // occurs. @@ -965,7 +960,6 @@ namespace { bool singleReply = (isCheck && mp.number_of_moves() == 1); bool moveIsCheck = pos.move_is_check(move, dcCandidates); bool moveIsCapture = pos.move_is_capture(move); - bool moveIsPassedPawnPush = pos.move_is_passed_pawn_push(move); movesSearched[moveCount++] = ss[ply].currentMove = move; @@ -977,7 +971,8 @@ namespace { ss[ply].currentMoveCaptureValue = Value(0); // Decide the new search depth - Depth ext = extension(pos, move, true, moveIsCheck, singleReply, mateThreat); + bool dangerous; + Depth ext = extension(pos, move, true, moveIsCheck, singleReply, mateThreat, &dangerous); Depth newDepth = depth - OnePly + ext; // Make and search the move @@ -991,11 +986,10 @@ namespace { // Try to reduce non-pv search depth by one ply if move seems not problematic, // if the move fails high will be re-searched at full depth. if ( depth >= 2*OnePly - && ext == Depth(0) && moveCount >= LMRPVMoves + && !dangerous && !moveIsCapture && !move_promotion(move) - && !moveIsPassedPawnPush && !move_is_castle(move) && !move_is_killer(move, ss[ply])) { @@ -1079,11 +1073,7 @@ namespace { if (ok_to_history(pos, m)) // Only non capture moves are considered { update_history(pos, m, depth, movesSearched, moveCount); - if (m != ss[ply].killers[0]) - { - ss[ply].killers[1] = ss[ply].killers[0]; - ss[ply].killers[0] = m; - } + update_killers(m, ss[ply]); } TT.store(pos, value_to_tt(bestValue, ply), depth, m, VALUE_TYPE_LOWER); } @@ -1223,19 +1213,18 @@ namespace { bool singleReply = (isCheck && mp.number_of_moves() == 1); bool moveIsCheck = pos.move_is_check(move, dcCandidates); bool moveIsCapture = pos.move_is_capture(move); - bool moveIsPassedPawnPush = pos.move_is_passed_pawn_push(move); movesSearched[moveCount++] = ss[ply].currentMove = move; // Decide the new search depth - Depth ext = extension(pos, move, false, moveIsCheck, singleReply, mateThreat); + bool dangerous; + Depth ext = extension(pos, move, false, moveIsCheck, singleReply, mateThreat, &dangerous); Depth newDepth = depth - OnePly + ext; // Futility pruning if ( useFutilityPruning - && ext == Depth(0) + && !dangerous && !moveIsCapture - && !moveIsPassedPawnPush && !move_promotion(move)) { if ( moveCount >= 2 + int(depth) @@ -1263,12 +1252,11 @@ namespace { // Try to reduce non-pv search depth by one ply if move seems not problematic, // if the move fails high will be re-searched at full depth. - if ( depth >= 2*OnePly - && ext == Depth(0) - && moveCount >= LMRNonPVMoves + if ( depth >= 2*OnePly + && moveCount >= LMRNonPVMoves + && !dangerous && !moveIsCapture && !move_promotion(move) - && !moveIsPassedPawnPush && !move_is_castle(move) && !move_is_killer(move, ss[ply])) { @@ -1329,11 +1317,7 @@ namespace { if (ok_to_history(pos, m)) // Only non capture moves are considered { update_history(pos, m, depth, movesSearched, moveCount); - if (m != ss[ply].killers[0]) - { - ss[ply].killers[1] = ss[ply].killers[0]; - ss[ply].killers[0] = m; - } + update_killers(m, ss[ply]); } TT.store(pos, value_to_tt(bestValue, ply), depth, m, VALUE_TYPE_LOWER); } @@ -1405,20 +1389,17 @@ namespace { { assert(move_is_ok(move)); - bool moveIsCheck = pos.move_is_check(move, dcCandidates); - bool moveIsPassedPawnPush = pos.move_is_passed_pawn_push(move); - moveCount++; ss[ply].currentMove = move; // Futility pruning if ( UseQSearchFutilityPruning + && enoughMaterial && !isCheck - && !moveIsCheck - && !move_promotion(move) - && !moveIsPassedPawnPush && !pvNode - && enoughMaterial) + && !move_promotion(move) + && !pos.move_is_check(move, dcCandidates) + && !pos.move_is_passed_pawn_push(move)) { Value futilityValue = staticValue + Max(pos.midgame_value_of_piece_on(move_to(move)), @@ -1437,7 +1418,6 @@ namespace { // Don't search captures and checks with negative SEE values if ( !isCheck && !move_promotion(move) - && !pvNode && (pos.midgame_value_of_piece_on(move_from(move)) > pos.midgame_value_of_piece_on(move_to(move))) && pos.see(move) < 0) @@ -1478,12 +1458,7 @@ namespace { if (alpha >= beta && ok_to_history(pos, m)) // Only non capture moves are considered { // Wrong to update history when depth is <= 0 - - if (m != ss[ply].killers[0]) - { - ss[ply].killers[1] = ss[ply].killers[0]; - ss[ply].killers[0] = m; - } + update_killers(m, ss[ply]); } return bestValue; } @@ -1519,7 +1494,6 @@ namespace { bool moveIsCheck = pos.move_is_check(move, sp->dcCandidates); bool moveIsCapture = pos.move_is_capture(move); - bool moveIsPassedPawnPush = pos.move_is_passed_pawn_push(move); lock_grab(&(sp->lock)); int moveCount = ++sp->moves; @@ -1528,14 +1502,14 @@ namespace { ss[sp->ply].currentMove = move; // Decide the new search depth. - Depth ext = extension(pos, move, false, moveIsCheck, false, false); + bool dangerous; + Depth ext = extension(pos, move, false, moveIsCheck, false, false, &dangerous); Depth newDepth = sp->depth - OnePly + ext; // Prune? if ( useFutilityPruning - && ext == Depth(0) + && !dangerous && !moveIsCapture - && !moveIsPassedPawnPush && !move_promotion(move) && moveCount >= 2 + int(sp->depth) && ok_to_prune(pos, move, ss[sp->ply].threatMove, sp->depth)) @@ -1547,10 +1521,9 @@ namespace { // Try to reduce non-pv search depth by one ply if move seems not problematic, // if the move fails high will be re-searched at full depth. - if ( ext == Depth(0) + if ( !dangerous && moveCount >= LMRNonPVMoves && !moveIsCapture - && !moveIsPassedPawnPush && !move_promotion(move) && !move_is_castle(move) && !move_is_killer(move, ss[sp->ply])) @@ -1631,7 +1604,6 @@ namespace { { bool moveIsCheck = pos.move_is_check(move, sp->dcCandidates); bool moveIsCapture = pos.move_is_capture(move); - bool moveIsPassedPawnPush = pos.move_is_passed_pawn_push(move); assert(move_is_ok(move)); @@ -1645,7 +1617,8 @@ namespace { ss[sp->ply].currentMove = move; // Decide the new search depth. - Depth ext = extension(pos, move, true, moveIsCheck, false, false); + bool dangerous; + Depth ext = extension(pos, move, true, moveIsCheck, false, false, &dangerous); Depth newDepth = sp->depth - OnePly + ext; // Make and search the move. @@ -1654,10 +1627,9 @@ namespace { // Try to reduce non-pv search depth by one ply if move seems not problematic, // if the move fails high will be re-searched at full depth. - if ( ext == Depth(0) + if ( !dangerous && moveCount >= LMRPVMoves && !moveIsCapture - && !moveIsPassedPawnPush && !move_promotion(move) && !move_is_castle(move) && !move_is_killer(move, ss[sp->ply])) @@ -1891,7 +1863,7 @@ namespace { // init_search_stack() initializes a search stack at the beginning of a // new search from the root. - void init_search_stack(SearchStack ss) { + void init_search_stack(SearchStack& ss) { ss.pv[0] = MOVE_NONE; ss.pv[1] = MOVE_NONE; @@ -1899,7 +1871,7 @@ namespace { ss.threatMove = MOVE_NONE; ss.reduction = Depth(0); for (int j = 0; j < KILLER_MAX; j++) - ss.killers[j] = MOVE_NONE; + ss.killers[j] = MOVE_NONE; } void init_search_stack(SearchStack ss[]) { @@ -1936,13 +1908,13 @@ namespace { NodesSincePoll = 0; } } - ss[ply].pv[ply] = ss[ply].pv[ply+1] = ss[ply].currentMove = MOVE_NONE; ss[ply+2].mateKiller = MOVE_NONE; - ss[ply+2].killers[0] = ss[ply+2].killers[1] = MOVE_NONE; ss[ply].threatMove = MOVE_NONE; ss[ply].reduction = Depth(0); ss[ply].currentMoveCaptureValue = Value(0); + for (int j = 0; j < KILLER_MAX; j++) + ss[ply+2].killers[j] = MOVE_NONE; if(Threads[threadID].printCurrentLine) print_current_line(ss, ply, threadID); @@ -2049,7 +2021,7 @@ namespace { // killer moves of that ply. bool move_is_killer(Move m, const SearchStack& ss) { - + const Move* k = ss.killers; for (int i = 0; i < KILLER_MAX; i++, k++) if (*k == m) @@ -2061,12 +2033,16 @@ namespace { // extension() decides whether a move should be searched with normal depth, // or with extended depth. Certain classes of moves (checking moves, in - // particular) are searched with bigger depth than ordinary moves. + // particular) are searched with bigger depth than ordinary moves and in + // any case are marked as 'dangerous'. Note that also if a move is not + // 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. - Depth extension(const Position &pos, Move m, bool pvNode, - bool check, bool singleReply, bool mateThreat) { + Depth extension(const Position &pos, Move m, bool pvNode, bool check, + bool singleReply, bool mateThreat, bool* dangerous) { Depth result = Depth(0); + *dangerous = check || singleReply || mateThreat; if (check) result += CheckExtension[pvNode]; @@ -2074,26 +2050,37 @@ namespace { if (singleReply) result += SingleReplyExtension[pvNode]; + if (mateThreat) + result += MateThreatExtension[pvNode]; + if (pos.move_is_pawn_push_to_7th(m)) + { result += PawnPushTo7thExtension[pvNode]; - + *dangerous = true; + } if (pos.move_is_passed_pawn_push(m)) + { result += PassedPawnExtension[pvNode]; - - if (mateThreat) - result += MateThreatExtension[pvNode]; + *dangerous = true; + } if ( pos.midgame_value_of_piece_on(move_to(m)) >= RookValueMidgame && ( pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK) - pos.midgame_value_of_piece_on(move_to(m)) == Value(0)) && !move_promotion(m)) + { result += PawnEndgameExtension[pvNode]; - + *dangerous = true; + } + if ( pvNode && pos.move_is_capture(m) && pos.type_of_piece_on(move_to(m)) != PAWN && pos.see(m) >= 0) + { result += OnePly/2; + *dangerous = true; + } return Min(result, OnePly); } @@ -2206,6 +2193,21 @@ namespace { } } + + // update_killers() add a good move that produced a beta-cutoff + // among the killer moves of that ply. + + void update_killers(Move m, SearchStack& ss) { + + if (m == ss.killers[0]) + return; + + for (int i = KILLER_MAX - 1; i > 0; i--) + ss.killers[i] = ss.killers[i - 1]; + + ss.killers[0] = m; + } + // fail_high_ply_1() checks if some thread is currently resolving a fail // high at ply 1 at the node below the first root node. This information // is used for time managment.