X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fpawns.cpp;h=0a88c9f1ba37b07a3738800fea6d11f0c003ec09;hp=edd670b84cc4ec3021fdcd2b3962bbd419cfdc88;hb=893a08a8c2eac3c2e7d2216b51811cc7378e2239;hpb=e917bd59b1e317c6b48dc676473359fdfb86d9d4 diff --git a/src/pawns.cpp b/src/pawns.cpp index edd670b8..0a88c9f1 100644 --- a/src/pawns.cpp +++ b/src/pawns.cpp @@ -36,8 +36,8 @@ namespace { constexpr Score Doubled = S(11, 56); constexpr Score Isolated = S( 5, 15); - // Connected pawn bonus by opposed, phalanx, #support and rank - Score Connected[2][2][3][RANK_NB]; + // Connected pawn bonus + constexpr int Connected[RANK_NB] = { 0, 13, 17, 24, 59, 96, 171 }; // Strength of pawn shelter for our king by [distance from edge][rank]. // RANK_1 = 0 is used for files where we have no pawn, or pawn is behind our king. @@ -78,11 +78,8 @@ namespace { Bitboard theirPawns = pos.pieces(Them, PAWN); e->passedPawns[Us] = e->pawnAttacksSpan[Us] = e->weakUnopposed[Us] = 0; - e->semiopenFiles[Us] = 0xFF; e->kingSquares[Us] = SQ_NONE; e->pawnAttacks[Us] = pawn_attacks_bb(ourPawns); - e->pawnsOnSquares[Us][BLACK] = popcount(ourPawns & DarkSquares); - e->pawnsOnSquares[Us][WHITE] = pos.count(Us) - e->pawnsOnSquares[Us][BLACK]; // Loop through all pawns of the current color and score each pawn while ((s = *pl++) != SQ_NONE) @@ -90,13 +87,13 @@ namespace { assert(pos.piece_on(s) == make_piece(Us, PAWN)); File f = file_of(s); + Rank r = relative_rank(Us, s); - e->semiopenFiles[Us] &= ~(1 << f); e->pawnAttacksSpan[Us] |= pawn_attack_span(Us, s); // Flag the pawn opposed = theirPawns & forward_file_bb(Us, s); - stoppers = theirPawns & passed_pawn_mask(Us, s); + stoppers = theirPawns & passed_pawn_span(Us, s); lever = theirPawns & PawnAttacks[Us][s]; leverPush = theirPawns & PawnAttacks[Us][s + Up]; doubled = ourPawns & (s - Up); @@ -114,12 +111,11 @@ namespace { // which could become passed after one or two pawn pushes when are // not attacked more times than defended. if ( !(stoppers ^ lever ^ leverPush) - && popcount(support) >= popcount(lever) - 1 - && popcount(phalanx) >= popcount(leverPush)) + && (support || !more_than_one(lever)) + && popcount(phalanx) >= popcount(leverPush)) e->passedPawns[Us] |= s; - else if ( stoppers == SquareBB[s + Up] - && relative_rank(Us, s) >= RANK_5) + else if (stoppers == square_bb(s + Up) && r >= RANK_5) { b = shift(support) & ~theirPawns; while (b) @@ -129,8 +125,11 @@ namespace { // Score this pawn if (support | phalanx) - score += Connected[opposed][bool(phalanx)][popcount(support)][relative_rank(Us, s)]; - + { + int v = (phalanx ? 3 : 2) * Connected[r]; + v = 17 * popcount(support) + (v >> (opposed + 1)); + score += make_score(v, v * (r - 2) / 4); + } else if (!neighbours) score -= Isolated, e->weakUnopposed[Us] += !opposed; @@ -148,27 +147,6 @@ namespace { namespace Pawns { -/// Pawns::init() initializes some tables needed by evaluation. Instead of using -/// hard-coded tables, when makes sense, we prefer to calculate them with a formula -/// to reduce independent parameters and to allow easier tuning and better insight. - -void init() { - - static constexpr int Seed[RANK_NB] = { 0, 13, 24, 18, 65, 100, 175, 330 }; - - for (int opposed = 0; opposed <= 1; ++opposed) - for (int phalanx = 0; phalanx <= 1; ++phalanx) - for (int support = 0; support <= 2; ++support) - for (Rank r = RANK_2; r < RANK_8; ++r) - { - int v = 17 * support; - v += (Seed[r] + (phalanx ? (Seed[r + 1] - Seed[r]) / 2 : 0)) >> opposed; - - Connected[opposed][phalanx][support][r] = make_score(v, v * (r - 2) / 4); - } -} - - /// Pawns::probe() looks up the current position's pawns configuration in /// the pawns hash table. It returns a pointer to the Entry if the position /// is found. Otherwise a new Entry is computed and stored there, so we don't @@ -185,9 +163,6 @@ Entry* probe(const Position& pos) { e->key = key; e->scores[WHITE] = evaluate(pos, e); e->scores[BLACK] = evaluate(pos, e); - e->openFiles = popcount(e->semiopenFiles[WHITE] & e->semiopenFiles[BLACK]); - e->asymmetry = popcount( (e->passedPawns[WHITE] | e->passedPawns[BLACK]) - | (e->semiopenFiles[WHITE] ^ e->semiopenFiles[BLACK])); return e; } @@ -201,16 +176,16 @@ Value Entry::evaluate_shelter(const Position& pos, Square ksq) { constexpr Color Them = (Us == WHITE ? BLACK : WHITE); constexpr Direction Down = (Us == WHITE ? SOUTH : NORTH); - constexpr Bitboard BlockRanks = (Us == WHITE ? Rank1BB | Rank2BB : Rank8BB | Rank7BB); + constexpr Bitboard BlockSquares = (Rank1BB | Rank2BB | Rank7BB | Rank8BB) + & (FileABB | FileHBB); Bitboard b = pos.pieces(PAWN) & ~forward_ranks_bb(Them, ksq); Bitboard ourPawns = b & pos.pieces(Us); Bitboard theirPawns = b & pos.pieces(Them); - Value safety = (shift(theirPawns) & (FileABB | FileHBB) & BlockRanks & ksq) ? - Value(374) : Value(5); + Value safety = (shift(theirPawns) & BlockSquares & ksq) ? Value(374) : Value(5); - File center = std::max(FILE_B, std::min(FILE_G, file_of(ksq))); + File center = clamp(file_of(ksq), FILE_B, FILE_G); for (File f = File(center - 1); f <= File(center + 1); ++f) { b = ourPawns & file_bb(f); @@ -238,11 +213,15 @@ Score Entry::do_king_safety(const Position& pos) { Square ksq = pos.square(Us); kingSquares[Us] = ksq; castlingRights[Us] = pos.castling_rights(Us); - int minKingPawnDistance = 0; Bitboard pawns = pos.pieces(Us, PAWN); - if (pawns) - while (!(DistanceRingBB[ksq][++minKingPawnDistance] & pawns)) {} + int minPawnDist = pawns ? 8 : 0; + + if (pawns & PseudoAttacks[KING][ksq]) + minPawnDist = 1; + + else while (pawns) + minPawnDist = std::min(minPawnDist, distance(ksq, pop_lsb(&pawns))); Value bonus = evaluate_shelter(pos, ksq); @@ -253,7 +232,7 @@ Score Entry::do_king_safety(const Position& pos) { if (pos.can_castle(Us | QUEEN_SIDE)) bonus = std::max(bonus, evaluate_shelter(pos, relative_square(Us, SQ_C1))); - return make_score(bonus, -16 * minKingPawnDistance); + return make_score(bonus, -16 * minPawnDist); } // Explicit template instantiation