X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=2b51a698b0de3e40c8208255251a92fc0149faf0;hp=bf227d1fb9d2ac034797cfbdb62d380dd65dd034;hb=4e31c39a6494499ba85db0e0014bbbaac9770b1d;hpb=cd80762c13961eb8fe0a89c0bb19d58e2808a1cf diff --git a/src/search.cpp b/src/search.cpp index bf227d1f..2b51a698 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -100,7 +100,7 @@ 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 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); @@ -1292,40 +1292,56 @@ split_point_start: // At split points actual search starts from here } - // 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. + // value_to_tt() adjusts a mate score from "plies to mate from the root" to + // "plies to mate from the current position". Non-mate scores are unchanged. + // The function is called before storing a value to the transposition table. + + Value value_to_tt(Value v, int ply) { + + assert(v != VALUE_NONE); + + return v >= VALUE_MATE_IN_MAX_PLY ? v + ply + : v <= VALUE_MATED_IN_MAX_PLY ? v - ply : v; + } + + + // value_from_tt() is the inverse of value_to_tt(): It adjusts a mate score + // from the transposition table (where refers to the plies to mate/be mated + // from current position) to "plies to mate/be mated from the root". + + Value value_from_tt(Value v, int ply) { + + return v == VALUE_NONE ? VALUE_NONE + : v >= VALUE_MATE_IN_MAX_PLY ? v - ply + : v <= VALUE_MATED_IN_MAX_PLY ? v + ply : v; + } - bool check_is_dangerous(Position &pos, Move move, Value futilityBase, Value beta) + + // check_is_dangerous() tests if a checking move can be pruned in qsearch() + + bool check_is_dangerous(Position& pos, Move move, Value futilityBase, Value beta) { - Bitboard b, occ, oldAtt, newAtt, kingAtt; - Square from, to, ksq; - Piece pc; - Color them; - - from = from_sq(move); - to = to_sq(move); - them = ~pos.side_to_move(); - ksq = pos.king_square(them); - kingAtt = pos.attacks_from(ksq); - pc = pos.piece_moved(move); - - occ = pos.pieces() ^ from ^ ksq; - oldAtt = pos.attacks_from(pc, from, occ); - newAtt = pos.attacks_from(pc, to, occ); - - // Rule 1. Checks which give opponent's king at most one escape square are dangerous - b = kingAtt & ~pos.pieces(them) & ~newAtt & ~(1ULL << to); - - if (!more_than_one(b)) + Piece pc = pos.piece_moved(move); + Square from = from_sq(move); + Square to = to_sq(move); + Color them = ~pos.side_to_move(); + Square ksq = pos.king_square(them); + Bitboard enemies = pos.pieces(them); + Bitboard kingAtt = pos.attacks_from(ksq); + Bitboard occ = pos.pieces() ^ from ^ ksq; + Bitboard oldAtt = pos.attacks_from(pc, from, occ); + Bitboard newAtt = pos.attacks_from(pc, to, occ); + + // Checks which give opponent's king at most one escape square are dangerous + if (!more_than_one(kingAtt & ~(enemies | newAtt | to))) return true; - // Rule 2. Queen contact check is very dangerous + // Queen contact check is very dangerous if (type_of(pc) == QUEEN && (kingAtt & to)) return true; - // Rule 3. Creating new double threats with checks - b = pos.pieces(them) & newAtt & ~oldAtt & ~(1ULL << ksq); + // Creating new double threats with checks is dangerous + Bitboard b = (enemies ^ ksq) & newAtt & ~oldAtt; while (b) { // Note that here we generate illegal "double move"! @@ -1385,31 +1401,6 @@ split_point_start: // At split points actual search starts from here } - // value_to_tt() adjusts a mate score from "plies to mate from the root" to - // "plies to mate from the current position". Non-mate scores are unchanged. - // The function is called before storing a value to the transposition table. - - Value value_to_tt(Value v, int ply) { - - assert(v != VALUE_NONE); - - return v >= VALUE_MATE_IN_MAX_PLY ? v + ply - : v <= VALUE_MATED_IN_MAX_PLY ? v - ply : v; - } - - - // value_from_tt() is the inverse of value_to_tt(): It adjusts a mate score - // from the transposition table (where refers to the plies to mate/be mated - // from current position) to "plies to mate/be mated from the root". - - Value value_from_tt(Value v, int ply) { - - return v == VALUE_NONE ? VALUE_NONE - : v >= VALUE_MATE_IN_MAX_PLY ? v - ply - : v <= VALUE_MATED_IN_MAX_PLY ? v + ply : v; - } - - // 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. @@ -1420,12 +1411,10 @@ split_point_start: // At split points actual search starts from here assert(!pos.is_capture_or_promotion(m)); assert(!pos.is_passed_pawn_push(m)); - Square mfrom, mto, tfrom, tto; - - mfrom = from_sq(m); - mto = to_sq(m); - tfrom = from_sq(threat); - tto = to_sq(threat); + Square mfrom = from_sq(m); + Square mto = to_sq(m); + Square tfrom = from_sq(threat); + Square tto = to_sq(threat); // Case 1: Don't prune moves which move the threatened piece if (mfrom == tto) @@ -1433,11 +1422,26 @@ split_point_start: // At split points actual search starts from here // 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) + if ( pos.is_capture(threat) && ( PieceValue[MG][pos.piece_on(tfrom)] >= PieceValue[MG][pos.piece_on(tto)] - || type_of(pos.piece_on(tfrom)) == KING) - && pos.move_attacks_square(m, tto)) - return true; + || type_of(pos.piece_on(tfrom)) == KING)) + { + // Update occupancy as if the piece is moving + Bitboard occ = pos.pieces() ^ mfrom ^ mto; + Piece piece = pos.piece_on(mfrom); + + // The moved piece attacks the square 'tto' ? + if (pos.attacks_from(piece, mto, occ) & tto) + 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)); + + // Verify attackers are triggered by our move and not already existing + if (xray && (xray ^ (xray & pos.attacks_from(tto)))) + return true; + } // Case 3: If the moving piece in the threatened move is a slider, don't // prune safe moves which block its ray. @@ -1500,23 +1504,24 @@ split_point_start: // At split points actual search starts from here std::stringstream s; Time::point elaspsed = Time::now() - SearchTime + 1; + size_t uciPVSize = std::min((size_t)Options["MultiPV"], RootMoves.size()); int selDepth = 0; for (size_t i = 0; i < Threads.size(); i++) if (Threads[i].maxPly > selDepth) selDepth = Threads[i].maxPly; - for (size_t i = 0; i < std::min((size_t)Options["MultiPV"], RootMoves.size()); i++) + for (size_t i = 0; i < uciPVSize; i++) { bool updated = (i <= PVIdx); if (depth == 1 && !updated) continue; - int d = (updated ? depth : depth - 1); - Value v = (updated ? RootMoves[i].score : RootMoves[i].prevScore); + int d = updated ? depth : depth - 1; + Value v = updated ? RootMoves[i].score : RootMoves[i].prevScore; - if (s.rdbuf()->in_avail()) + if (s.rdbuf()->in_avail()) // Not at first line s << "\n"; s << "info depth " << d