X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fevaluate.cpp;h=17c52e180019230d810be047d1ec971418c50844;hp=4c10a199243730db00ab89a471ee4ac393b99e5a;hb=3acacf8471efd018e33e4743cbbb2aed8d59e855;hpb=11967e89cdde6a15058d8f169d2b9bd0246011eb diff --git a/src/evaluate.cpp b/src/evaluate.cpp index 4c10a199..17c52e18 100644 --- a/src/evaluate.cpp +++ b/src/evaluate.cpp @@ -2,7 +2,7 @@ Stockfish, a UCI chess playing engine derived from Glaurung 2.1 Copyright (C) 2004-2008 Tord Romstad (Glaurung author) Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad - Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + Copyright (C) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad Stockfish is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -79,9 +79,9 @@ namespace { constexpr Bitboard Center = (FileDBB | FileEBB) & (Rank4BB | Rank5BB); constexpr Bitboard KingFlank[FILE_NB] = { - QueenSide, QueenSide, QueenSide, + QueenSide ^ FileDBB, QueenSide, QueenSide, CenterFiles, CenterFiles, - KingSide, KingSide, KingSide + KingSide, KingSide, KingSide ^ FileEBB }; // Threshold for lazy and space evaluation @@ -89,7 +89,7 @@ namespace { constexpr Value SpaceThreshold = Value(12222); // KingAttackWeights[PieceType] contains king attack weights by piece type - constexpr int KingAttackWeights[PIECE_TYPE_NB] = { 0, 0, 78, 56, 45, 11 }; + constexpr int KingAttackWeights[PIECE_TYPE_NB] = { 0, 0, 77, 55, 44, 10 }; // Penalties for enemy's safe checks constexpr int QueenSafeCheck = 780; @@ -102,8 +102,8 @@ namespace { // MobilityBonus[PieceType-2][attacked] contains bonuses for middle and end game, // indexed by piece type and number of attacked squares in the mobility area. constexpr Score MobilityBonus[][32] = { - { S(-75,-76), S(-57,-54), S( -9,-28), S( -2,-10), S( 6, 5), S( 14, 12), // Knights - S( 22, 26), S( 29, 29), S( 36, 29) }, + { S(-62,-81), S(-53,-56), S(-12,-30), S( -4,-14), S( 3, 8), S( 13, 15), // Knights + S( 22, 23), S( 28, 27), S( 33, 33) }, { S(-48,-59), S(-20,-23), S( 16, -3), S( 26, 13), S( 38, 24), S( 51, 42), // Bishops S( 55, 54), S( 63, 57), S( 63, 65), S( 68, 73), S( 81, 78), S( 81, 86), S( 91, 88), S( 98, 97) }, @@ -127,60 +127,50 @@ namespace { // RookOnFile[semiopen/open] contains bonuses for each rook when there is // no (friendly) pawn on the rook file. - constexpr Score RookOnFile[] = { S(20, 7), S(45, 20) }; + constexpr Score RookOnFile[] = { S(18, 7), S(44, 20) }; // ThreatByMinor/ByRook[attacked PieceType] contains bonuses according to // which piece type attacks which one. Attacks on lesser pieces which are // pawn-defended are not considered. constexpr Score ThreatByMinor[PIECE_TYPE_NB] = { - S(0, 0), S(0, 31), S(39, 42), S(57, 44), S(68, 112), S(47, 120) + S(0, 0), S(0, 31), S(39, 42), S(57, 44), S(68, 112), S(62, 120) }; constexpr Score ThreatByRook[PIECE_TYPE_NB] = { - S(0, 0), S(0, 24), S(38, 71), S(38, 61), S(0, 38), S(36, 38) + S(0, 0), S(0, 24), S(38, 71), S(38, 61), S(0, 38), S(51, 38) }; - // ThreatByKing[on one/on many] contains bonuses for king attacks on - // pawns or pieces which are not pawn-defended. - constexpr Score ThreatByKing[] = { S(3, 65), S(9, 145) }; - // PassedRank[Rank] contains a bonus according to the rank of a passed pawn constexpr Score PassedRank[RANK_NB] = { - S(0, 0), S(5, 7), S(5, 13), S(32, 42), S(70, 70), S(172, 170), S(217, 269) + S(0, 0), S(5, 18), S(12, 23), S(10, 31), S(57, 62), S(163, 167), S(271, 250) }; // PassedFile[File] contains a bonus according to the file of a passed pawn constexpr Score PassedFile[FILE_NB] = { - S( 9, 10), S(2, 10), S(1, -8), S(-20,-12), - S(-20,-12), S(1, -8), S(2, 10), S( 9, 10) + S( -1, 7), S( 0, 9), S(-9, -8), S(-30,-14), + S(-30,-14), S(-9, -8), S( 0, 9), S( -1, 7) }; - // PassedDanger[Rank] contains a term to weight the passed score - constexpr int PassedDanger[RANK_NB] = { 0, 0, 0, 2, 7, 12, 19 }; - - // KingProtector[PieceType-2] contains a penalty according to distance from king - constexpr Score KingProtector[] = { S(3, 5), S(4, 3), S(3, 0), S(1, -1) }; - // Assorted bonuses and penalties - constexpr Score BishopPawns = S( 8, 12); - constexpr Score CloseEnemies = S( 7, 0); - constexpr Score Connectivity = S( 3, 1); + constexpr Score BishopPawns = S( 3, 7); + constexpr Score CloseEnemies = S( 8, 0); constexpr Score CorneredBishop = S( 50, 50); - constexpr Score Hanging = S( 52, 30); - constexpr Score HinderPassedPawn = S( 8, 1); - constexpr Score KnightOnQueen = S( 21, 11); - constexpr Score LongDiagonalBishop = S( 22, 0); - constexpr Score MinorBehindPawn = S( 16, 0); - constexpr Score Overload = S( 10, 5); - constexpr Score PawnlessFlank = S( 20, 80); - constexpr Score RookOnPawn = S( 8, 24); - constexpr Score SliderOnQueen = S( 42, 21); - constexpr Score ThreatByPawnPush = S( 47, 26); - constexpr Score ThreatByRank = S( 16, 3); - constexpr Score ThreatBySafePawn = S(175,168); - constexpr Score TrappedRook = S( 92, 0); - constexpr Score WeakQueen = S( 50, 10); - constexpr Score WeakUnopposedPawn = S( 5, 25); + constexpr Score Hanging = S( 69, 36); + constexpr Score KingProtector = S( 7, 8); + constexpr Score KnightOnQueen = S( 16, 12); + constexpr Score LongDiagonalBishop = S( 45, 0); + constexpr Score MinorBehindPawn = S( 18, 3); + constexpr Score PawnlessFlank = S( 17, 95); + constexpr Score RestrictedPiece = S( 7, 7); + constexpr Score RookOnPawn = S( 10, 32); + constexpr Score SliderOnQueen = S( 59, 18); + constexpr Score ThreatByKing = S( 24, 89); + constexpr Score ThreatByPawnPush = S( 48, 39); + constexpr Score ThreatByRank = S( 13, 0); + constexpr Score ThreatBySafePawn = S(173, 94); + constexpr Score TrappedRook = S( 96, 4); + constexpr Score WeakQueen = S( 49, 15); + constexpr Score WeakUnopposedPawn = S( 12, 23); #undef S @@ -223,7 +213,7 @@ namespace { // kingRing[color] are the squares adjacent to the king, plus (only for a // king on its first rank) the squares two ranks in front. For instance, // if black's king is on g8, kingRing[BLACK] is f8, h8, f7, g7, h7, f6, g6 - // and h6. It is set to 0 when king safety evaluation is skipped. + // and h6. Bitboard kingRing[COLOR_NB]; // kingAttackersCount[color] is the number of pieces of the given color @@ -268,24 +258,20 @@ namespace { attackedBy[Us][ALL_PIECES] = attackedBy[Us][KING] | attackedBy[Us][PAWN]; attackedBy2[Us] = attackedBy[Us][KING] & attackedBy[Us][PAWN]; - // Init our king safety tables only if we are going to use them - if (pos.non_pawn_material(Them) >= RookValueMg + KnightValueMg) - { - kingRing[Us] = attackedBy[Us][KING]; - if (relative_rank(Us, pos.square(Us)) == RANK_1) - kingRing[Us] |= shift(kingRing[Us]); + // Init our king safety tables + kingRing[Us] = attackedBy[Us][KING]; + if (relative_rank(Us, pos.square(Us)) == RANK_1) + kingRing[Us] |= shift(kingRing[Us]); - if (file_of(pos.square(Us)) == FILE_H) - kingRing[Us] |= shift(kingRing[Us]); + if (file_of(pos.square(Us)) == FILE_H) + kingRing[Us] |= shift(kingRing[Us]); - else if (file_of(pos.square(Us)) == FILE_A) - kingRing[Us] |= shift(kingRing[Us]); + else if (file_of(pos.square(Us)) == FILE_A) + kingRing[Us] |= shift(kingRing[Us]); - kingAttackersCount[Them] = popcount(attackedBy[Us][KING] & pe->pawn_attacks(Them)); - kingAttacksCount[Them] = kingAttackersWeight[Them] = 0; - } - else - kingRing[Us] = kingAttackersCount[Them] = 0; + kingAttackersCount[Them] = popcount(kingRing[Us] & pe->pawn_attacks(Them)); + kingRing[Us] &= ~double_pawn_attacks_bb(pos.pieces(Us, PAWN)); + kingAttacksCount[Them] = kingAttackersWeight[Them] = 0; } @@ -293,7 +279,8 @@ namespace { template template Score Evaluation::pieces() { - constexpr Color Them = (Us == WHITE ? BLACK : WHITE); + constexpr Color Them = (Us == WHITE ? BLACK : WHITE); + constexpr Direction Down = (Us == WHITE ? SOUTH : NORTH); constexpr Bitboard OutpostRanks = (Us == WHITE ? Rank4BB | Rank5BB | Rank6BB : Rank5BB | Rank4BB | Rank3BB); const Square* pl = pos.squares(Us); @@ -329,9 +316,6 @@ namespace { mobility[Us] += MobilityBonus[Pt - 2][mob]; - // Penalty if the piece is far from the king - score -= KingProtector[Pt - 2] * distance(s, pos.square(Us)); - if (Pt == BISHOP || Pt == KNIGHT) { // Bonus if piece is on an outpost square or can reach one @@ -342,18 +326,24 @@ namespace { else if (bb &= b & ~pos.pieces(Us)) score += Outpost[Pt == BISHOP][bool(attackedBy[Us][PAWN] & bb)]; - // Bonus when behind a pawn - if ( relative_rank(Us, s) < RANK_5 - && (pos.pieces(PAWN) & (s + pawn_push(Us)))) + // Knight and Bishop bonus for being right behind a pawn + if (shift(pos.pieces(PAWN)) & s) score += MinorBehindPawn; + // Penalty if the piece is far from the king + score -= KingProtector * distance(s, pos.square(Us)); + if (Pt == BISHOP) { - // Penalty according to number of pawns on the same color square as the bishop - score -= BishopPawns * pe->pawns_on_same_color_squares(Us, s); + // Penalty according to number of pawns on the same color square as the + // bishop, bigger when the center files are blocked with pawns. + Bitboard blocked = pos.pieces(Us, PAWN) & shift(pos.pieces()); + + score -= BishopPawns * pe->pawns_on_same_color_squares(Us, s) + * (1 + popcount(blocked & CenterFiles)); // Bonus for bishop on a long diagonal which can "see" both center squares - if (more_than_one(Center & (attacks_bb(s, pos.pieces(PAWN)) | s))) + if (more_than_one(attacks_bb(s, pos.pieces(PAWN)) & Center)) score += LongDiagonalBishop; } @@ -387,7 +377,7 @@ namespace { { File kf = file_of(pos.square(Us)); if ((kf < FILE_E) == (file_of(s) < kf)) - score -= (TrappedRook - make_score(mob * 22, 0)) * (1 + !pos.can_castle(Us)); + score -= (TrappedRook - make_score(mob * 22, 0)) * (1 + !pos.castling_rights(Us)); } } @@ -415,90 +405,85 @@ namespace { : AllSquares ^ Rank1BB ^ Rank2BB ^ Rank3BB); const Square ksq = pos.square(Us); - Bitboard weak, b, b1, b2, safe, unsafeChecks, pinned; + Bitboard kingFlank, weak, b, b1, b2, safe, unsafeChecks; // King shelter and enemy pawns storm - Score score = pe->king_safety(pos, ksq); + Score score = pe->king_safety(pos); - // Main king safety evaluation - if (kingAttackersCount[Them] > 1 - pos.count(Them)) - { - int kingDanger = 0; - unsafeChecks = 0; + // Find the squares that opponent attacks in our king flank, and the squares + // which are attacked twice in that flank. + kingFlank = KingFlank[file_of(ksq)]; + b1 = attackedBy[Them][ALL_PIECES] & kingFlank & Camp; + b2 = b1 & attackedBy2[Them]; - // Attacked squares defended at most once by our queen or king - weak = attackedBy[Them][ALL_PIECES] - & ~attackedBy2[Us] - & (~attackedBy[Us][ALL_PIECES] | attackedBy[Us][KING] | attackedBy[Us][QUEEN]); + int tropism = popcount(b1) + popcount(b2); - // Analyse the safe enemy's checks which are possible on next move - safe = ~pos.pieces(Them); - safe &= ~attackedBy[Us][ALL_PIECES] | (weak & attackedBy2[Them]); + // Main king safety evaluation + int kingDanger = 0; + unsafeChecks = 0; - b1 = attacks_bb(ksq, pos.pieces() ^ pos.pieces(Us, QUEEN)); - b2 = attacks_bb(ksq, pos.pieces() ^ pos.pieces(Us, QUEEN)); + // Attacked squares defended at most once by our queen or king + weak = attackedBy[Them][ALL_PIECES] + & ~attackedBy2[Us] + & (~attackedBy[Us][ALL_PIECES] | attackedBy[Us][KING] | attackedBy[Us][QUEEN]); - // Enemy queen safe checks - if ((b1 | b2) & attackedBy[Them][QUEEN] & safe & ~attackedBy[Us][QUEEN]) - kingDanger += QueenSafeCheck; + // Analyse the safe enemy's checks which are possible on next move + safe = ~pos.pieces(Them); + safe &= ~attackedBy[Us][ALL_PIECES] | (weak & attackedBy2[Them]); - b1 &= attackedBy[Them][ROOK]; - b2 &= attackedBy[Them][BISHOP]; + b1 = attacks_bb(ksq, pos.pieces() ^ pos.pieces(Us, QUEEN)); + b2 = attacks_bb(ksq, pos.pieces() ^ pos.pieces(Us, QUEEN)); - // Enemy rooks checks - if (b1 & safe) - kingDanger += RookSafeCheck; - else - unsafeChecks |= b1; + // Enemy queen safe checks + if ((b1 | b2) & attackedBy[Them][QUEEN] & safe & ~attackedBy[Us][QUEEN]) + kingDanger += QueenSafeCheck; - // Enemy bishops checks - if (b2 & safe) - kingDanger += BishopSafeCheck; - else - unsafeChecks |= b2; + b1 &= attackedBy[Them][ROOK]; + b2 &= attackedBy[Them][BISHOP]; - // Enemy knights checks - b = pos.attacks_from(ksq) & attackedBy[Them][KNIGHT]; - if (b & safe) - kingDanger += KnightSafeCheck; - else - unsafeChecks |= b; - - // Unsafe or occupied checking squares will also be considered, as long as - // the square is in the attacker's mobility area. - unsafeChecks &= mobilityArea[Them]; - pinned = pos.blockers_for_king(Us) & pos.pieces(Us); - - kingDanger += kingAttackersCount[Them] * kingAttackersWeight[Them] - + 102 * kingAttacksCount[Them] - + 191 * popcount(kingRing[Us] & weak) - + 143 * popcount(pinned | unsafeChecks) - - 848 * !pos.count(Them) - - 9 * mg_value(score) / 8 - + 40; - - // Transform the kingDanger units into a Score, and subtract it from the evaluation - if (kingDanger > 0) - { - int mobilityDanger = mg_value(mobility[Them] - mobility[Us]); - kingDanger = std::max(0, kingDanger + mobilityDanger); - score -= make_score(kingDanger * kingDanger / 4096, kingDanger / 16); - } - } + // Enemy rooks checks + if (b1 & safe) + kingDanger += RookSafeCheck; + else + unsafeChecks |= b1; + + // Enemy bishops checks + if (b2 & safe) + kingDanger += BishopSafeCheck; + else + unsafeChecks |= b2; - Bitboard kf = KingFlank[file_of(ksq)]; + // Enemy knights checks + b = pos.attacks_from(ksq) & attackedBy[Them][KNIGHT]; + if (b & safe) + kingDanger += KnightSafeCheck; + else + unsafeChecks |= b; + + // Unsafe or occupied checking squares will also be considered, as long as + // the square is in the attacker's mobility area. + unsafeChecks &= mobilityArea[Them]; + + kingDanger += kingAttackersCount[Them] * kingAttackersWeight[Them] + + 69 * kingAttacksCount[Them] + + 185 * popcount(kingRing[Us] & weak) + + 150 * popcount(pos.blockers_for_king(Us) | unsafeChecks) + + tropism * tropism / 4 + - 873 * !pos.count(Them) + - 6 * mg_value(score) / 8 + + mg_value(mobility[Them] - mobility[Us]) + - 30; + + // Transform the kingDanger units into a Score, and subtract it from the evaluation + if (kingDanger > 0) + score -= make_score(kingDanger * kingDanger / 4096, kingDanger / 16); // Penalty when our king is on a pawnless flank - if (!(pos.pieces(PAWN) & kf)) + if (!(pos.pieces(PAWN) & kingFlank)) score -= PawnlessFlank; - // Find the squares that opponent attacks in our king flank, and the squares - // which are attacked twice in that flank but not defended by our pawns. - b1 = attackedBy[Them][ALL_PIECES] & kf & Camp; - b2 = b1 & attackedBy2[Them] & ~attackedBy[Us][PAWN]; - - // King tropism, to anticipate slow motion attacks on our king - score -= CloseEnemies * (popcount(b1) + popcount(b2)); + // King tropism bonus, to anticipate slow motion attacks on our king + score -= CloseEnemies * tropism; if (T) Trace::add(KING, Us, score); @@ -516,11 +501,11 @@ namespace { constexpr Direction Up = (Us == WHITE ? NORTH : SOUTH); constexpr Bitboard TRank3BB = (Us == WHITE ? Rank3BB : Rank6BB); - Bitboard b, weak, defended, nonPawnEnemies, stronglyProtected, safeThreats; + Bitboard b, weak, defended, nonPawnEnemies, stronglyProtected, safe, restricted; Score score = SCORE_ZERO; // Non-pawn enemies - nonPawnEnemies = pos.pieces(Them) ^ pos.pieces(Them, PAWN); + nonPawnEnemies = pos.pieces(Them) & ~pos.pieces(PAWN); // Squares strongly protected by the enemy, either because they defend the // square with a pawn, or because they defend the square twice and we don't. @@ -533,6 +518,9 @@ namespace { // Enemies not strongly protected and under our attack weak = pos.pieces(Them) & ~stronglyProtected & attackedBy[Us][ALL_PIECES]; + // Safe or protected squares + safe = ~attackedBy[Them][ALL_PIECES] | attackedBy[Us][ALL_PIECES]; + // Bonus according to the kind of attacking pieces if (defended | weak) { @@ -545,7 +533,7 @@ namespace { score += ThreatByRank * (int)relative_rank(Them, s); } - b = (pos.pieces(Them, QUEEN) | weak) & attackedBy[Us][ROOK]; + b = weak & attackedBy[Us][ROOK]; while (b) { Square s = pop_lsb(&b); @@ -554,65 +542,57 @@ namespace { score += ThreatByRank * (int)relative_rank(Them, s); } - b = weak & attackedBy[Us][KING]; - if (b) - score += ThreatByKing[more_than_one(b)]; + if (weak & attackedBy[Us][KING]) + score += ThreatByKing; - score += Hanging * popcount(weak & ~attackedBy[Them][ALL_PIECES]); - - // Bonus for overload (non-pawn enemies attacked and defended exactly once) - b = nonPawnEnemies - & attackedBy[Us][ALL_PIECES] & ~attackedBy2[Us] - & attackedBy[Them][ALL_PIECES] & ~attackedBy2[Them]; - score += Overload * popcount(b); + b = ~attackedBy[Them][ALL_PIECES] + | (nonPawnEnemies & attackedBy2[Us]); + score += Hanging * popcount(weak & b); } + // Bonus for restricting their piece moves + restricted = attackedBy[Them][ALL_PIECES] + & ~stronglyProtected + & attackedBy[Us][ALL_PIECES]; + score += RestrictedPiece * popcount(restricted); + // Bonus for enemy unopposed weak pawns if (pos.pieces(Us, ROOK, QUEEN)) score += WeakUnopposedPawn * pe->weak_unopposed(Them); - // Our safe or protected pawns - b = pos.pieces(Us, PAWN) - & (~attackedBy[Them][ALL_PIECES] | attackedBy[Us][ALL_PIECES]); - - safeThreats = pawn_attacks_bb(b) & nonPawnEnemies; - score += ThreatBySafePawn * popcount(safeThreats); - // Find squares where our pawns can push on the next move b = shift(pos.pieces(Us, PAWN)) & ~pos.pieces(); b |= shift(b & TRank3BB) & ~pos.pieces(); - // Keep only the squares which are not completely unsafe - b &= ~attackedBy[Them][PAWN] - & (attackedBy[Us][ALL_PIECES] | ~attackedBy[Them][ALL_PIECES]); + // Keep only the squares which are relatively safe + b &= ~attackedBy[Them][PAWN] & safe; // Bonus for safe pawn threats on the next move - b = pawn_attacks_bb(b) - & pos.pieces(Them) - & ~attackedBy[Us][PAWN]; - + b = pawn_attacks_bb(b) & pos.pieces(Them); score += ThreatByPawnPush * popcount(b); + // Our safe or protected pawns + b = pos.pieces(Us, PAWN) & safe; + + b = pawn_attacks_bb(b) & nonPawnEnemies; + score += ThreatBySafePawn * popcount(b); + // Bonus for threats on the next moves against enemy queen if (pos.count(Them) == 1) { Square s = pos.square(Them); - safeThreats = mobilityArea[Us] & ~stronglyProtected; + safe = mobilityArea[Us] & ~stronglyProtected; b = attackedBy[Us][KNIGHT] & pos.attacks_from(s); - score += KnightOnQueen * popcount(b & safeThreats); + score += KnightOnQueen * popcount(b & safe); b = (attackedBy[Us][BISHOP] & pos.attacks_from(s)) | (attackedBy[Us][ROOK ] & pos.attacks_from(s)); - score += SliderOnQueen * popcount(b & safeThreats & attackedBy2[Us]); + score += SliderOnQueen * popcount(b & safe & attackedBy2[Us]); } - // Connectivity: ensure that knights, bishops, rooks, and queens are protected - b = (pos.pieces(Us) ^ pos.pieces(Us, PAWN, KING)) & attackedBy[Us][ALL_PIECES]; - score += Connectivity * popcount(b); - if (T) Trace::add(THREAT, Us, score); @@ -643,16 +623,13 @@ namespace { assert(!(pos.pieces(Them, PAWN) & forward_file_bb(Us, s + Up))); - bb = forward_file_bb(Us, s) & (attackedBy[Them][ALL_PIECES] | pos.pieces(Them)); - score -= HinderPassedPawn * popcount(bb); - int r = relative_rank(Us, s); - int w = PassedDanger[r]; Score bonus = PassedRank[r]; - if (w) + if (r > RANK_3) { + int w = (r-2) * (r-2) + 2; Square blockSq = s + Up; // Adjust bonus based on the king's proximity @@ -693,9 +670,7 @@ namespace { bonus += make_score(k * w, k * w); } - else if (pos.pieces(Us) & blockSq) - bonus += make_score(w + r * 2, w + r * 2); - } // w != 0 + } // rank > RANK_3 // Scale down bonus for candidate passers which need more than one // pawn push to become passed, or have a pawn in front of them. @@ -723,14 +698,14 @@ namespace { template template Score Evaluation::space() const { + if (pos.non_pawn_material() < SpaceThreshold) + return SCORE_ZERO; + constexpr Color Them = (Us == WHITE ? BLACK : WHITE); constexpr Bitboard SpaceMask = Us == WHITE ? CenterFiles & (Rank2BB | Rank3BB | Rank4BB) : CenterFiles & (Rank7BB | Rank6BB | Rank5BB); - if (pos.non_pawn_material() < SpaceThreshold) - return SCORE_ZERO; - // Find the available squares for our pieces inside the area defined by SpaceMask Bitboard safe = SpaceMask & ~pos.pieces(Us, PAWN) @@ -742,7 +717,8 @@ namespace { behind |= (Us == WHITE ? behind >> 16 : behind << 16); int bonus = popcount(safe) + popcount(behind & safe); - int weight = pos.count(Us) - 2 * pe->open_files(); + int weight = pos.count(Us) + - 2 * popcount(pe->semiopenFiles[WHITE] & pe->semiopenFiles[BLACK]); Score score = make_score(bonus * weight * weight / 16, 0); @@ -767,12 +743,12 @@ namespace { && (pos.pieces(PAWN) & KingSide); // Compute the initiative bonus for the attacking side - int complexity = 8 * outflanking - + 8 * pe->pawn_asymmetry() - + 12 * pos.count() - + 16 * pawnsOnBothFlanks - + 48 * !pos.non_pawn_material() - -136 ; + int complexity = 9 * pe->pawn_asymmetry() + + 11 * pos.count() + + 9 * outflanking + + 18 * pawnsOnBothFlanks + + 49 * !pos.non_pawn_material() + -121 ; // Now apply the bonus: note that we find the attacking side by extracting // the sign of the endgame value, and that we carefully cap the bonus so @@ -794,28 +770,16 @@ namespace { Color strongSide = eg > VALUE_DRAW ? WHITE : BLACK; int sf = me->scale_factor(pos, strongSide); - // If we don't already have an unusual scale factor, check for certain - // types of endgames, and use a lower scale for those. - if (sf == SCALE_FACTOR_NORMAL || sf == SCALE_FACTOR_ONEPAWN) + // If scale is not already specific, scale down the endgame via general heuristics + if (sf == SCALE_FACTOR_NORMAL) { - if (pos.opposite_bishops()) - { - // Endgame with opposite-colored bishops and no other pieces is almost a draw - if ( pos.non_pawn_material(WHITE) == BishopValueMg - && pos.non_pawn_material(BLACK) == BishopValueMg) - sf = 31; - - // Endgame with opposite-colored bishops, but also other pieces. Still - // a bit drawish, but not as drawish as with only the two bishops. - else - sf = 46; - } - // Endings where weaker side can place his king in front of the enemy's - // pawns are drawish. - else if ( abs(eg) <= BishopValueEg - && pos.count(strongSide) <= 2 - && !pos.pawn_passed(~strongSide, pos.square(~strongSide))) - sf = 37 + 7 * pos.count(strongSide); + if ( pos.opposite_bishops() + && pos.non_pawn_material(WHITE) == BishopValueMg + && pos.non_pawn_material(BLACK) == BishopValueMg) + sf = 8 + 4 * pe->pawn_asymmetry(); + else + sf = std::min(40 + (pos.opposite_bishops() ? 2 : 7) * pos.count(strongSide), sf); + } return ScaleFactor(sf);