X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fpawns.cpp;h=04222a2aa4ee98544afd22d193850c5012fa5ba4;hp=9755c2ec2e0e20258f046610797efb40a40c65e7;hb=de4e1cb88d9d5a6b4bf6e47bdc2a71e025bf8f46;hpb=33c3a0465358116560174ae7421144be714e43f9 diff --git a/src/pawns.cpp b/src/pawns.cpp index 9755c2ec..04222a2a 100644 --- a/src/pawns.cpp +++ b/src/pawns.cpp @@ -33,6 +33,7 @@ namespace { // Pawn penalties constexpr Score Backward = S( 9, 24); + constexpr Score BlockedStorm = S(82, 82); constexpr Score Doubled = S(11, 56); constexpr Score Isolated = S( 5, 15); constexpr Score WeakLever = S( 0, 56); @@ -52,13 +53,13 @@ namespace { // Danger of enemy pawns moving toward our king by [distance from edge][rank]. // RANK_1 = 0 is used for files where the enemy has no pawn, or their pawn - // is behind our king. - // [0][1-2] accommodate opponent pawn on edge (likely blocked by our king) + // is behind our king. Note that UnblockedStorm[0][1-2] accommodate opponent pawn + // on edge, likely blocked by our king. constexpr Value UnblockedStorm[int(FILE_NB) / 2][RANK_NB] = { - { V( 89), V(-285), V(-185), V(93), V(57), V( 45), V( 51) }, - { V( 44), V( -18), V( 123), V(46), V(39), V( -7), V( 23) }, - { V( 4), V( 52), V( 162), V(37), V( 7), V(-14), V( -2) }, - { V(-10), V( -14), V( 90), V(15), V( 2), V( -7), V(-16) } + { V( 85), V(-289), V(-166), V(97), V(50), V( 45), V( 50) }, + { V( 46), V( -25), V( 122), V(45), V(37), V(-10), V( 20) }, + { V( -6), V( 51), V( 168), V(34), V(-2), V(-22), V(-14) }, + { V(-15), V( -11), V( 101), V( 4), V(11), V(-15), V(-29) } }; #undef S @@ -68,12 +69,12 @@ namespace { Score evaluate(const Position& pos, Pawns::Entry* e) { constexpr Color Them = (Us == WHITE ? BLACK : WHITE); - constexpr Direction Up = (Us == WHITE ? NORTH : SOUTH); + constexpr Direction Up = pawn_push(Us); - Bitboard b, neighbours, stoppers, doubled, support, phalanx; - Bitboard lever, leverPush; + Bitboard neighbours, stoppers, support, phalanx, opposed; + Bitboard lever, leverPush, blocked; Square s; - bool opposed, backward, passed; + bool backward, passed, doubled; Score score = SCORE_ZERO; const Square* pl = pos.squares(Us); @@ -82,9 +83,9 @@ namespace { Bitboard doubleAttackThem = pawn_double_attacks_bb(theirPawns); - e->passedPawns[Us] = e->pawnAttacksSpan[Us] = 0; + e->passedPawns[Us] = 0; e->kingSquares[Us] = SQ_NONE; - e->pawnAttacks[Us] = pawn_attacks_bb(ourPawns); + e->pawnAttacks[Us] = e->pawnAttacksSpan[Us] = pawn_attacks_bb(ourPawns); // Loop through all pawns of the current color and score each pawn while ((s = *pl++) != SQ_NONE) @@ -93,10 +94,9 @@ namespace { Rank r = relative_rank(Us, s); - e->pawnAttacksSpan[Us] |= pawn_attack_span(Us, s); - // Flag the pawn opposed = theirPawns & forward_file_bb(Us, s); + blocked = theirPawns & (s + Up); stoppers = theirPawns & passed_pawn_span(Us, s); lever = theirPawns & PawnAttacks[Us][s]; leverPush = theirPawns & PawnAttacks[Us][s + Up]; @@ -106,10 +106,13 @@ namespace { support = neighbours & rank_bb(s - Up); // A pawn is backward when it is behind all pawns of the same color on - // the adjacent files and cannot safely advance. Phalanx and isolated - // pawns will be excluded when the pawn is scored. - backward = !(neighbours & forward_ranks_bb(Them, s)) - && (stoppers & (leverPush | (s + Up))); + // the adjacent files and cannot safely advance. + backward = !(neighbours & forward_ranks_bb(Them, s + Up)) + && (leverPush | blocked); + + // Compute additional span if pawn is not backward nor blocked + if (!backward && !blocked) + e->pawnAttacksSpan[Us] |= pawn_attack_span(Us, s); // A pawn is passed if one of the three following conditions is true: // (a) there is no stoppers except some levers @@ -118,7 +121,7 @@ namespace { passed = !(stoppers ^ lever) || ( !(stoppers ^ leverPush) && popcount(phalanx) >= popcount(leverPush)) - || ( stoppers == square_bb(s + Up) && r >= RANK_5 + || ( stoppers == blocked && r >= RANK_5 && (shift(support) & ~(theirPawns | doubleAttackThem))); // Passed pawns will be properly scored later in evaluation when we have @@ -129,28 +132,25 @@ namespace { // Score this pawn if (support | phalanx) { - int v = Connected[r] * (phalanx ? 3 : 2) / (opposed ? 2 : 1) - + 17 * popcount(support); + int v = Connected[r] * (2 + bool(phalanx) - bool(opposed)) + + 21 * popcount(support); score += make_score(v, v * (r - 2) / 4); } else if (!neighbours) - score -= Isolated + WeakUnopposed * int(!opposed); + score -= Isolated + + WeakUnopposed * !opposed; else if (backward) - score -= Backward + WeakUnopposed * int(!opposed); + score -= Backward + + WeakUnopposed * !opposed; - if (doubled && !support) - score -= Doubled; + if (!support) + score -= Doubled * doubled + + WeakLever * more_than_one(lever); } - // Penalize the unsupported and non passed pawns attacked twice by the enemy - b = ourPawns - & doubleAttackThem - & ~(e->pawnAttacks[Us] | e->passedPawns[Us]); - score -= WeakLever * popcount(b); - return score; } @@ -183,7 +183,7 @@ Entry* probe(const Position& pos) { /// penalty for a king, looking at the king file and the two closest files. template -void Entry::evaluate_shelter(const Position& pos, Square ksq, Score& shelter) { +Score Entry::evaluate_shelter(const Position& pos, Square ksq) { constexpr Color Them = (Us == WHITE ? BLACK : WHITE); @@ -197,22 +197,21 @@ void Entry::evaluate_shelter(const Position& pos, Square ksq, Score& shelter) { for (File f = File(center - 1); f <= File(center + 1); ++f) { b = ourPawns & file_bb(f); - Rank ourRank = b ? relative_rank(Us, frontmost_sq(Them, b)) : RANK_1; + int ourRank = b ? relative_rank(Us, frontmost_sq(Them, b)) : 0; b = theirPawns & file_bb(f); - Rank theirRank = b ? relative_rank(Us, frontmost_sq(Them, b)) : RANK_1; + int theirRank = b ? relative_rank(Us, frontmost_sq(Them, b)) : 0; - int d = std::min(f, ~f); + File d = map_to_queenside(f); bonus += make_score(ShelterStrength[d][ourRank], 0); if (ourRank && (ourRank == theirRank - 1)) - bonus -= make_score(82 * (theirRank == RANK_3), 82 * (theirRank == RANK_3)); + bonus -= BlockedStorm * int(theirRank == RANK_3); else bonus -= make_score(UnblockedStorm[d][theirRank], 0); } - if (mg_value(bonus) > mg_value(shelter)) - shelter = bonus; + return bonus; } @@ -225,27 +224,28 @@ Score Entry::do_king_safety(const Position& pos) { Square ksq = pos.square(Us); kingSquares[Us] = ksq; castlingRights[Us] = pos.castling_rights(Us); + auto compare = [](Score a, Score b) { return mg_value(a) < mg_value(b); }; + + Score shelter = evaluate_shelter(pos, ksq); + + // If we can castle use the bonus after castling if it is bigger + + if (pos.can_castle(Us & KING_SIDE)) + shelter = std::max(shelter, evaluate_shelter(pos, relative_square(Us, SQ_G1)), compare); + if (pos.can_castle(Us & QUEEN_SIDE)) + shelter = std::max(shelter, evaluate_shelter(pos, relative_square(Us, SQ_C1)), compare); + + // In endgame we like to bring our king near our closest pawn Bitboard pawns = pos.pieces(Us, PAWN); int minPawnDist = pawns ? 8 : 0; if (pawns & PseudoAttacks[KING][ksq]) minPawnDist = 1; - else while (pawns) minPawnDist = std::min(minPawnDist, distance(ksq, pop_lsb(&pawns))); - Score shelter = make_score(-VALUE_INFINITE, VALUE_ZERO); - evaluate_shelter(pos, ksq, shelter); - - // If we can castle use the bonus after the castling if it is bigger - if (pos.can_castle(Us | KING_SIDE)) - evaluate_shelter(pos, relative_square(Us, SQ_G1), shelter); - - if (pos.can_castle(Us | QUEEN_SIDE)) - evaluate_shelter(pos, relative_square(Us, SQ_C1), shelter); - - return shelter - make_score(VALUE_ZERO, 16 * minPawnDist); + return shelter - make_score(0, 16 * minPawnDist); } // Explicit template instantiation