X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fpawns.cpp;h=47f74f84ee77888d60dacf0e03251977d3cc82ff;hp=ef456307cafbacb4479a53627a7a1d7b58aa362d;hb=e6310b3469b07b6bbecf8d8f75367a655090f22b;hpb=1277a428237eec3299c6606951fac014bb3ef851 diff --git a/src/pawns.cpp b/src/pawns.cpp index ef456307..47f74f84 100644 --- a/src/pawns.cpp +++ b/src/pawns.cpp @@ -43,15 +43,11 @@ namespace { { S(25, 30), S(36, 35), S(40, 35), S(40, 35), S(40, 35), S(40, 35), S(36, 35), S(25, 30) } }; - // 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) } }; + // Backward pawn penalty by opposed flag + const Score Backward[2] = { S(67, 42), S(49, 24) }; - // 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] = { @@ -61,31 +57,39 @@ namespace { // Unsupported pawn penalty const Score UnsupportedPawnPenalty = S(20, 10); + // Center bind bonus: Two pawns controlling the same central square + const Bitboard CenterBindMask[COLOR_NB] = { + (FileDBB | FileEBB) & (Rank5BB | Rank6BB | Rank7BB), + (FileDBB | FileEBB) & (Rank4BB | Rank3BB | Rank2BB) + }; + + const Score CenterBind = S(16, 0); + // Weakness of our pawn shelter in front of the king by [distance from edge][rank] const Value ShelterWeakness[][RANK_NB] = { - { V( 99), V(20), V(26), V(54), V(85), V( 92), V(108) }, - { V(117), V( 1), V(27), V(71), V(94), V(104), V(118) }, - { V(104), V( 4), V(51), V(76), V(82), V(102), V( 97) }, - { V( 80), V(12), V(43), V(65), V(88), V( 91), V(115) } }; + { V( 97), V(21), V(26), V(51), V(87), V( 89), V( 99) }, + { V(120), V( 0), V(28), V(76), V(88), V(103), V(104) }, + { V(101), V( 7), V(54), V(78), V(77), V( 92), V(101) }, + { V( 80), V(11), V(44), V(68), V(87), V( 90), V(119) } }; // Danger of enemy pawns moving toward our king by [type][distance from edge][rank] const Value StormDanger[][4][RANK_NB] = { - { { V( 0), V( 65), V( 126), V(36), V(30) }, - { V( 0), V( 55), V( 135), V(36), V(23) }, - { V( 0), V( 47), V( 116), V(45), V(26) }, - { V( 0), V( 62), V( 127), V(57), V(34) } }, - { { V(21), V( 45), V( 93), V(50), V(19) }, - { V(23), V( 24), V( 105), V(41), V(13) }, - { V(23), V( 36), V( 101), V(38), V(20) }, - { V(30), V( 19), V( 110), V(41), V(27) } }, - { { V( 0), V( 0), V( 81), V(14), V( 4) }, - { V( 0), V( 0), V( 169), V(30), V( 3) }, - { V( 0), V( 0), V( 168), V(24), V( 5) }, - { V( 0), V( 0), V( 162), V(26), V(10) } }, - { { V( 0), V(-283), V(-298), V(57), V(29) }, - { V( 0), V( 63), V( 137), V(42), V(18) }, - { V( 0), V( 67), V( 145), V(49), V(33) }, - { V( 0), V( 62), V( 126), V(53), V(21) } } }; + { { V( 0), V( 67), V( 134), V(38), V(32) }, + { V( 0), V( 57), V( 139), V(37), V(22) }, + { V( 0), V( 43), V( 115), V(43), V(27) }, + { V( 0), V( 68), V( 124), V(57), V(32) } }, + { { V(20), V( 43), V( 100), V(56), V(20) }, + { V(23), V( 20), V( 98), V(40), V(15) }, + { V(23), V( 39), V( 103), V(36), V(18) }, + { V(28), V( 19), V( 108), V(42), V(26) } }, + { { V( 0), V( 0), V( 75), V(14), V( 2) }, + { V( 0), V( 0), V( 150), V(30), V( 4) }, + { V( 0), V( 0), V( 160), V(22), V( 5) }, + { V( 0), V( 0), V( 166), V(24), V(13) } }, + { { V( 0), V(-283), V(-281), V(57), V(31) }, + { V( 0), V( 58), V( 141), V(39), V(18) }, + { V( 0), V( 65), V( 142), V(48), V(32) }, + { V( 0), V( 60), V( 126), V(51), V(19) } } }; // Max bonus for king safety. Corresponds to start position with all the pawns // in front of the king and no enemy pawn on the horizon. @@ -102,11 +106,11 @@ 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 Square* pl = pos.squares(Us); const Bitboard* pawnAttacksBB = StepAttacksBB[make_piece(Us, PAWN)]; Bitboard ourPawns = pos.pieces(Us , PAWN); @@ -129,30 +133,28 @@ 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. + // or if it is sufficiently advanced, it cannot be backward either. if ( (passed | isolated | lever | connected) - || (ourPawns & pawn_attack_span(Them, s))) + || (ourPawns & pawn_attack_span(Them, s)) + || (relative_rank(Us, s) >= RANK_5)) 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. @@ -176,18 +178,18 @@ namespace { if (isolated) score -= Isolated[opposed][f]; - if (unsupported && !isolated) + else if (backward) + score -= Backward[opposed]; + + 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)]; } @@ -195,6 +197,10 @@ namespace { b = e->semiopenFiles[Us] ^ 0xFF; e->pawnSpan[Us] = b ? int(msb(b) - lsb(b)) : 0; + // Center binds: Two pawns controlling the same central square + b = shift_bb(ourPawns) & shift_bb(ourPawns) & CenterBindMask[Us]; + score += popcount(b) * CenterBind; + return score; } @@ -212,11 +218,13 @@ 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); + } } @@ -283,14 +291,14 @@ 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); @@ -301,7 +309,7 @@ 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