X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fpawns.cpp;h=0bc2a632ae9b0304f0927c20621d912ce52e668e;hp=f767f6dbcbf442af1b4455ff01571f093a8bc8cf;hb=2312c2672299d6e13b2f509bf5b1a6e330662f09;hpb=402a7ae151cfc6090c8f6682763b0fb3729bf8ca diff --git a/src/pawns.cpp b/src/pawns.cpp index f767f6db..0bc2a632 100644 --- a/src/pawns.cpp +++ b/src/pawns.cpp @@ -57,9 +57,17 @@ namespace { S( 0, 0), S( 6, 13), S(6,13), S(14,29), S(34,68), S(83,166), S(0, 0), S( 0, 0) }; + // Levers bonus by rank + const Score Lever[RANK_NB] = { + S( 0, 0), S( 0, 0), S(0, 0), S(0, 0), + S(20,20), S(40,40), S(0, 0), S(0, 0) }; + // Bonus for file distance of the two outermost pawns const Score PawnsFileSpan = S(0, 15); + // Unsupported pawn penalty + const Score UnsupportedPawnPenalty = S(20, 10); + // Weakness of our pawn shelter in front of the king indexed by [rank] const Value ShelterWeakness[RANK_NB] = { V(100), V(0), V(27), V(73), V(92), V(101), V(101) }; @@ -69,7 +77,7 @@ namespace { const Value StormDanger[3][RANK_NB] = { { V( 0), V(64), V(128), V(51), V(26) }, { V(26), V(32), V( 96), V(38), V(20) }, - { V( 0), V( 0), V( 64), V(25), V(13) } }; + { V( 0), V( 0), V(160), V(25), V(13) } }; // 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. @@ -85,11 +93,12 @@ namespace { const Square Up = (Us == WHITE ? DELTA_N : DELTA_S); const Square Right = (Us == WHITE ? DELTA_NE : DELTA_SW); const Square Left = (Us == WHITE ? DELTA_NW : DELTA_SE); + const Piece pc = make_piece(Us, PAWN); - Bitboard b; + Bitboard b, p, doubled; Square s; File f; - bool passed, isolated, doubled, opposed, connected, backward, candidate; + bool passed, isolated, opposed, connected, backward, candidate, unsupported, lever; Score value = SCORE_ZERO; const Square* pl = pos.list(Us); @@ -113,16 +122,21 @@ namespace { // This file cannot be semi-open e->semiopenFiles[Us] &= ~(1 << f); - // Our rank plus previous one - b = rank_bb(s) | rank_bb(s - pawn_push(Us)); + // Previous rank + p = rank_bb(s - pawn_push(Us)); - // Flag the pawn as passed, isolated, doubled or - // connected (but not the backward one). - connected = ourPawns & adjacent_files_bb(f) & b; - isolated = !(ourPawns & adjacent_files_bb(f)); - doubled = ourPawns & forward_bb(Us, s); - opposed = theirPawns & forward_bb(Us, s); - passed = !(theirPawns & passed_pawn_mask(Us, s)); + // Our rank plus previous one + b = rank_bb(s) | p; + + // Flag the pawn as passed, isolated, doubled, + // unsupported or connected (but not the backward one). + connected = ourPawns & adjacent_files_bb(f) & b; + unsupported = !(ourPawns & adjacent_files_bb(f) & p); + isolated = !(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 & StepAttacksBB[pc][s]; // Test for backward pawn. // If the pawn is passed, isolated, or connected it cannot be @@ -166,8 +180,11 @@ namespace { if (isolated) value -= Isolated[opposed][f]; + if (unsupported && !isolated) + value -= UnsupportedPawnPenalty; + if (doubled) - value -= Doubled[f]; + value -= Doubled[f] / rank_distance(s, lsb(doubled)); if (backward) value -= Backward[opposed][f]; @@ -182,6 +199,9 @@ namespace { if (!doubled) e->candidatePawns[Us] |= s; } + + if (lever) + value += Lever[relative_rank(Us, s)]; } // In endgame it's better to have pawns on both wings. So give a bonus according @@ -257,10 +277,10 @@ Value Entry::shelter_storm(const Position& pos, Square ksq) { b = theirPawns & file_bb(f); rkThem = b ? relative_rank(Us, frontmost_sq(Them, b)) : RANK_1; - if ( (MiddleEdges & (f | rkThem)) + if ( (MiddleEdges & make_square(f, rkThem)) && file_of(ksq) == f && relative_rank(Us, ksq) == rkThem - 1) - safety += Value(200); + safety += 200; else safety -= ShelterWeakness[rkUs] + StormDanger[rkUs == RANK_1 ? 0 : rkThem == rkUs + 1 ? 2 : 1][rkThem]; @@ -270,15 +290,14 @@ Value Entry::shelter_storm(const Position& pos, Square ksq) { } -/// Entry::update_safety() calculates and caches a bonus for king safety. -/// It is called only when king square changes, which is about 20% of total -/// king_safety() calls. +/// Entry::do_king_safety() calculates a bonus for king safety. It is called only +/// when king square changes, which is about 20% of total king_safety() calls. template -Score Entry::update_safety(const Position& pos, Square ksq) { +Score Entry::do_king_safety(const Position& pos, Square ksq) { kingSquares[Us] = ksq; - castlingFlags[Us] = pos.can_castle(Us); + castlingRights[Us] = pos.can_castle(Us); minKPdistance[Us] = 0; Bitboard pawns = pos.pieces(Us, PAWN); @@ -286,22 +305,22 @@ Score Entry::update_safety(const Position& pos, Square ksq) { while (!(DistanceRingsBB[ksq][minKPdistance[Us]++] & pawns)) {} if (relative_rank(Us, ksq) > RANK_4) - return kingSafety[Us] = make_score(0, -16 * minKPdistance[Us]); + return make_score(0, -16 * minKPdistance[Us]); Value bonus = shelter_storm(pos, ksq); // If we can castle use the bonus after the castling if it is bigger - if (pos.can_castle(make_castling_flag(Us, KING_SIDE))) + if (pos.can_castle(MakeCastling::right)) bonus = std::max(bonus, shelter_storm(pos, relative_square(Us, SQ_G1))); - if (pos.can_castle(make_castling_flag(Us, QUEEN_SIDE))) + if (pos.can_castle(MakeCastling::right)) bonus = std::max(bonus, shelter_storm(pos, relative_square(Us, SQ_C1))); - return kingSafety[Us] = make_score(bonus, -16 * minKPdistance[Us]); + return make_score(bonus, -16 * minKPdistance[Us]); } // Explicit template instantiation -template Score Entry::update_safety(const Position& pos, Square ksq); -template Score Entry::update_safety(const Position& pos, Square ksq); +template Score Entry::do_king_safety(const Position& pos, Square ksq); +template Score Entry::do_king_safety(const Position& pos, Square ksq); } // namespace Pawns