X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fpawns.cpp;h=5290efb2c70c2eb4fcd72cfe60ff774ced77000a;hp=d66233caa3f876da9ef8ffb9fe718e6350c4f819;hb=8463fa479ee2841f852fdf57374b08c87b61e227;hpb=ce8ac7997c9ddb34c28859a5b9afde0e2b6a4a9d diff --git a/src/pawns.cpp b/src/pawns.cpp index d66233ca..5290efb2 100644 --- a/src/pawns.cpp +++ b/src/pawns.cpp @@ -45,13 +45,13 @@ namespace { // Backward pawn penalty by opposed flag and file const Score Backward[2][FILE_NB] = { - { S(30, 42), S(43, 46), S(49, 46), S(49, 46), - S(49, 46), S(49, 46), S(43, 46), S(30, 42) }, - { S(20, 28), S(29, 31), S(33, 31), S(33, 31), - S(33, 31), S(33, 31), S(29, 31), S(20, 28) } }; + { S(50, 52), S(63, 56), S(69, 56), S(69, 56), + S(69, 56), S(69, 56), S(63, 56), S(50, 52) }, + { S(40, 38), S(49, 41), S(53, 41), S(53, 41), + S(53, 41), S(53, 41), S(49, 41), S(40, 38) } }; - // Connected pawn bonus by opposed, phalanx flags and rank - Score Connected[2][2][RANK_NB]; + // Connected pawn bonus by opposed, phalanx, twice supported and rank + Score Connected[2][2][2][RANK_NB]; // Levers bonus by rank const Score Lever[RANK_NB] = { @@ -110,9 +110,9 @@ namespace { const Square Right = (Us == WHITE ? DELTA_NE : DELTA_SW); const Square Left = (Us == WHITE ? DELTA_NW : DELTA_SE); - Bitboard b, p, doubled, connected; + Bitboard b, neighbours, doubled, supported, phalanx; Square s; - bool passed, isolated, opposed, phalanx, backward, unsupported, lever; + bool passed, isolated, opposed, backward, lever, connected; Score score = SCORE_ZERO; const Square* pl = pos.list(Us); const Bitboard* pawnAttacksBB = StepAttacksBB[make_piece(Us, PAWN)]; @@ -137,22 +137,19 @@ namespace { // This file cannot be semi-open e->semiopenFiles[Us] &= ~(1 << f); - // Previous rank - p = rank_bb(s - pawn_push(Us)); - - // Flag the pawn as passed, isolated, doubled, - // unsupported or connected (but not the backward one). - connected = ourPawns & adjacent_files_bb(f) & (rank_bb(s) | p); - phalanx = connected & rank_bb(s); - unsupported = !(ourPawns & adjacent_files_bb(f) & p); - isolated = !(ourPawns & adjacent_files_bb(f)); + // Flag the pawn + neighbours = ourPawns & adjacent_files_bb(f); doubled = ourPawns & forward_bb(Us, s); opposed = theirPawns & forward_bb(Us, s); passed = !(theirPawns & passed_pawn_mask(Us, s)); lever = theirPawns & pawnAttacksBB[s]; + phalanx = neighbours & rank_bb(s); + supported = neighbours & rank_bb(s - Up); + connected = supported | phalanx; + isolated = !neighbours; // Test for backward pawn. - // If the pawn is passed, isolated, connected or a lever it cannot be + // If the pawn is passed, isolated, lever or connected it cannot be // backward. If there are friendly pawns behind on adjacent files // it cannot be backward either. if ( (passed | isolated | lever | connected) @@ -160,7 +157,7 @@ namespace { backward = false; else { - // We now know that there are no friendly pawns beside or behind this + // We now know there are no friendly pawns beside or behind this // pawn on adjacent files. We now check whether the pawn is // backward by looking in the forward direction on the adjacent // files, and picking the closest pawn there. @@ -183,19 +180,17 @@ namespace { // Score this pawn if (isolated) score -= Isolated[opposed][f]; - - if (unsupported && !isolated) + else if (backward) + score -= Backward[opposed][f]; + else if (!supported) score -= UnsupportedPawnPenalty; + if (connected) + score += Connected[opposed][!!phalanx][more_than_one(supported)][relative_rank(Us, s)]; + if (doubled) score -= Doubled[f] / distance(s, frontmost_sq(Us, doubled)); - - if (backward) - score -= Backward[opposed][f]; - - if (connected) - score += Connected[opposed][phalanx][relative_rank(Us, s)]; - + if (lever) score += Lever[relative_rank(Us, s)]; } @@ -224,11 +219,13 @@ void init() for (int opposed = 0; opposed <= 1; ++opposed) for (int phalanx = 0; phalanx <= 1; ++phalanx) - for (Rank r = RANK_2; r < RANK_8; ++r) - { - int bonus = Seed[r] + (phalanx ? (Seed[r + 1] - Seed[r]) / 2 : 0); - Connected[opposed][phalanx][r] = make_score(bonus / 2, bonus >> opposed); - } + for (int apex = 0; apex <= 1; ++apex) + for (Rank r = RANK_2; r < RANK_8; ++r) + { + int v = (Seed[r] + (phalanx ? (Seed[r + 1] - Seed[r]) / 2 : 0)) >> opposed; + v += (apex ? v / 2 : 0); + Connected[opposed][phalanx][apex][r] = make_score(3 * v / 2, v); + } } @@ -295,14 +292,14 @@ Score Entry::do_king_safety(const Position& pos, Square ksq) { kingSquares[Us] = ksq; castlingRights[Us] = pos.can_castle(Us); - minKingPawnDistance[Us] = 0; + int minKingPawnDistance = 0; Bitboard pawns = pos.pieces(Us, PAWN); if (pawns) - while (!(DistanceRingBB[ksq][minKingPawnDistance[Us]++] & pawns)) {} + while (!(DistanceRingBB[ksq][minKingPawnDistance++] & pawns)) {} if (relative_rank(Us, ksq) > RANK_4) - return make_score(0, -16 * minKingPawnDistance[Us]); + return make_score(0, -16 * minKingPawnDistance); Value bonus = shelter_storm(pos, ksq); @@ -313,7 +310,7 @@ Score Entry::do_king_safety(const Position& pos, Square ksq) { if (pos.can_castle(MakeCastling::right)) bonus = std::max(bonus, shelter_storm(pos, relative_square(Us, SQ_C1))); - return make_score(bonus, -16 * minKingPawnDistance[Us]); + return make_score(bonus, -16 * minKingPawnDistance); } // Explicit template instantiation