X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fevaluate.cpp;h=b0bebce6256e10c0868380530023eabca1b98521;hp=03d537d52bc42bdfb7678167fae89969b7b2a434;hb=2c237da54647bb7526f3512bea183eb44919cdda;hpb=307a5a4f63169fd215860dc478dcf2a9db2c46e8 diff --git a/src/evaluate.cpp b/src/evaluate.cpp index 03d537d5..b0bebce6 100644 --- a/src/evaluate.cpp +++ b/src/evaluate.cpp @@ -2,6 +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) 2015-2017 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 @@ -23,7 +24,7 @@ #include #include -#include "bitcount.h" +#include "bitboard.h" #include "evaluate.h" #include "material.h" #include "pawns.h" @@ -32,7 +33,7 @@ namespace { namespace Trace { - enum Term { // First 8 entries are for PieceType + enum Term { // The first 8 entries are for PieceType MATERIAL = 8, IMBALANCE, MOBILITY, THREAT, PASSED, SPACE, TOTAL, TERM_NB }; @@ -72,13 +73,22 @@ namespace { // by the evaluation functions. struct EvalInfo { + Material::Entry* me; + Pawns::Entry* pe; + Bitboard mobilityArea[COLOR_NB]; + // attackedBy[color][piece type] is a bitboard representing all squares // attacked by a given color and piece type (can be also ALL_PIECES). Bitboard attackedBy[COLOR_NB][PIECE_TYPE_NB]; + // attackedBy2[color] are the squares attacked by 2 pieces of a given color, + // possibly via x-ray or by one pawn and one piece. Diagonal x-ray through + // pawn or squares attacked by 2 pawns are not explicitly added. + Bitboard attackedBy2[COLOR_NB]; + // kingRing[color] is the zone around the king which is considered // by the king safety evaluation. This consists of the squares directly - // adjacent to the king, and the three (or two, for a king on an edge file) + // adjacent to the king, and (only for a king on its first rank) the // squares two ranks in front of the king. For instance, if black's king // is on g8, kingRing[BLACK] is a bitboard containing the squares f8, h8, // f7, g7, h7, f6, g6 and h6. @@ -88,7 +98,7 @@ namespace { // which attack a square in the kingRing of the enemy king. int kingAttackersCount[COLOR_NB]; - // kingAttackersWeight[color] is the sum of the "weight" of the pieces of the + // kingAttackersWeight[color] is the sum of the "weights" of the pieces of the // given color which attack a square in the kingRing of the enemy king. The // weights of the individual piece types are given by the elements in the // KingAttackWeights array. @@ -100,96 +110,88 @@ namespace { // a white knight on g5 and black's king is on g8, this white knight adds 2 // to kingAdjacentZoneAttacksCount[WHITE]. int kingAdjacentZoneAttacksCount[COLOR_NB]; - - Bitboard pinnedPieces[COLOR_NB]; - Pawns::Entry* pi; - }; - - - // Evaluation weights, indexed by the corresponding evaluation term - enum { Mobility, PawnStructure, PassedPawns, Space, KingSafety }; - - const struct Weight { int mg, eg; } Weights[] = { - {289, 344}, {233, 201}, {221, 273}, {46, 0}, {322, 0} }; - Score operator*(Score s, const Weight& w) { - return make_score(mg_value(s) * w.mg / 256, eg_value(s) * w.eg / 256); - } - - #define V(v) Value(v) #define S(mg, eg) make_score(mg, eg) - // MobilityBonus[PieceType][attacked] contains bonuses for middle and end - // game, indexed by piece type and number of attacked squares not occupied by - // friendly pieces. + // MobilityBonus[PieceType-2][attacked] contains bonuses for middle and end game, + // indexed by piece type and number of attacked squares in the mobility area. const Score MobilityBonus[][32] = { - {}, {}, - { S(-70,-52), S(-52,-37), S( -7,-17), S( 0, -6), S( 8, 5), S( 16, 9), // Knights - S( 23, 20), S( 31, 21), S( 36, 22) }, - { S(-49,-44), S(-22,-13), S( 16, 0), S( 27, 11), S( 38, 19), S( 52, 34), // Bishops - S( 56, 44), S( 65, 47), S( 67, 51), S( 73, 56), S( 81, 59), S( 83, 69), - S( 95, 72), S(100, 75) }, - { S(-49,-57), S(-22,-14), S(-10, 18), S( -5, 39), S( -4, 50), S( -2, 58), // Rooks - S( 6, 78), S( 11, 86), S( 17, 92), S( 19,103), S( 26,111), S( 27,115), - S( 36,119), S( 41,121), S( 50,122) }, - { S(-41,-24), S(-26, -8), S( 0, 6), S( 2, 14), S( 12, 27), S( 21, 40), // Queens - S( 22, 45), S( 37, 55), S( 40, 57), S( 43, 63), S( 50, 68), S( 52, 74), - S( 56, 80), S( 66, 84), S( 68, 85), S( 69, 88), S( 71, 92), S( 72, 94), - S( 80, 96), S( 89, 98), S( 94,101), S(102,113), S(106,114), S(107,116), - S(112,125), S(113,127), S(117,137), S(122,143) } + { 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(-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) }, + { S(-58,-76), S(-27,-18), S(-15, 28), S(-10, 55), S( -5, 69), S( -2, 82), // Rooks + S( 9,112), S( 16,118), S( 30,132), S( 29,142), S( 32,155), S( 38,165), + S( 46,166), S( 48,169), S( 58,171) }, + { S(-39,-36), S(-21,-15), S( 3, 8), S( 3, 18), S( 14, 34), S( 22, 54), // Queens + S( 28, 61), S( 41, 73), S( 43, 79), S( 48, 92), S( 56, 94), S( 60,104), + S( 60,113), S( 66,120), S( 67,123), S( 70,126), S( 71,133), S( 73,136), + S( 79,140), S( 88,143), S( 88,148), S( 99,166), S(102,170), S(102,175), + S(106,184), S(109,191), S(113,206), S(116,212) } }; - // Outpost[knight/bishop][supported by pawn] contains bonuses for knights and - // bishops outposts, bigger if outpost piece is supported by a pawn. + // Outpost[knight/bishop][supported by pawn] contains bonuses for minor + // pieces if they can reach an outpost square, bigger if that square is + // supported by a pawn. If the minor piece occupies an outpost square + // then score is doubled. const Score Outpost[][2] = { - { S(42,11), S(63,17) }, // Knights - { S(18, 5), S(27, 8) } // Bishops + { S(22, 6), S(33, 9) }, // Knight + { S( 9, 2), S(14, 4) } // Bishop }; - // Threat[minor/rook][attacked PieceType] contains - // bonuses according to which piece type attacks which one. - // Attacks on lesser pieces which are pawn defended are not considered. - const Score Threat[2][PIECE_TYPE_NB] = { - { S(0, 0), S(0, 32), S(25, 39), S(28, 44), S(42, 98), S(35,105) }, // Minor attacks - { S(0, 0), S(0, 27), S(26, 57), S(26, 57), S( 0, 30), S(23, 51) } // Rook attacks + // RookOnFile[semiopen/open] contains bonuses for each rook when there is no + // friendly pawn on the rook file. + const Score RookOnFile[] = { S(20, 7), S(45, 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. + const Score ThreatByMinor[PIECE_TYPE_NB] = { + S(0, 0), S(0, 33), S(45, 43), S(46, 47), S(72, 107), S(48, 118) }; - // ThreatenedByPawn[PieceType] contains a penalty according to which piece - // type is attacked by a pawn. - const Score ThreatenedByPawn[PIECE_TYPE_NB] = { - S(0, 0), S(0, 0), S(107, 138), S(84, 122), S(114, 203), S(121, 217) + const Score ThreatByRook[PIECE_TYPE_NB] = { + S(0, 0), S(0, 25), S(40, 62), S(40, 59), S(0, 34), S(35, 48) }; - // Passed[mg/eg][rank] contains midgame and endgame bonuses for passed pawns. + // ThreatByKing[on one/on many] contains bonuses for king attacks on + // pawns or pieces which are not pawn-defended. + const Score ThreatByKing[] = { S(3, 62), S(9, 138) }; + + // Passed[mg/eg][Rank] contains midgame and endgame bonuses for passed pawns. // We don't use a Score because we process the two components independently. const Value Passed[][RANK_NB] = { - { V(0), V( 1), V(34), V(90), V(214), V(328) }, - { V(7), V(14), V(37), V(63), V(134), V(189) } + { V(5), V( 5), V(31), V(73), V(166), V(252) }, + { V(7), V(14), V(38), V(73), V(166), V(252) } }; - // PassedFile[File] contains a bonus according to the file of a passed pawn. - const Score PassedFile[] = { - S( 12, 10), S( 3, 10), S( 1, -8), S(-27, -12), - S(-27, -12), S( 1, -8), S( 3, 10), S( 12, 10) + // PassedFile[File] contains a bonus according to the file of a passed pawn + const 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) }; - const Score ThreatenedByHangingPawn = S(40, 60); + // KingProtector[PieceType-2] contains a bonus according to distance from king + const Score KingProtector[] = { S(-3, -5), S(-4, -3), S(-3, 0), S(-1, 1) }; // Assorted bonuses and penalties used by evaluation - const Score KingOnOne = S( 2, 58); - const Score KingOnMany = S( 6,125); - const Score RookOnPawn = S( 7, 27); - const Score RookOnOpenFile = S(43, 21); - const Score RookOnSemiOpenFile = S(19, 10); - const Score BishopPawns = S( 8, 12); - const Score MinorBehindPawn = S(16, 0); - const Score TrappedRook = S(92, 0); - const Score Unstoppable = S( 0, 20); - const Score Hanging = S(31, 26); - const Score PawnAttackThreat = S(20, 20); - const Score Checked = S(20, 20); + const Score MinorBehindPawn = S( 16, 0); + const Score BishopPawns = S( 8, 12); + const Score RookOnPawn = S( 8, 24); + const Score TrappedRook = S( 92, 0); + const Score WeakQueen = S( 50, 10); + const Score OtherCheck = S( 10, 10); + const Score CloseEnemies = S( 7, 0); + const Score PawnlessFlank = S( 20, 80); + const Score ThreatByHangingPawn = S( 71, 61); + const Score ThreatBySafePawn = S(182,175); + const Score ThreatByRank = S( 16, 3); + const Score Hanging = S( 48, 27); + const Score ThreatByPawnPush = S( 38, 22); + const Score HinderPassedPawn = S( 7, 0); // Penalty for a bishop on a1/h1 (a8/h8 for black) which is trapped by // a friendly pawn on b2/g2 (b7/g7 for black). This can obviously only @@ -199,72 +201,75 @@ namespace { #undef S #undef V - // SpaceMask[Color] contains the area of the board which is considered - // by the space evaluation. In the middlegame, each side is given a bonus - // based on how many squares inside this area are safe and available for - // friendly minor pieces. - const Bitboard SpaceMask[COLOR_NB] = { - (FileCBB | FileDBB | FileEBB | FileFBB) & (Rank2BB | Rank3BB | Rank4BB), - (FileCBB | FileDBB | FileEBB | FileFBB) & (Rank7BB | Rank6BB | Rank5BB) - }; - - // King danger constants and variables. The king danger scores are looked-up - // in KingDanger[]. Various little "meta-bonuses" measuring the strength - // of the enemy attack are added up into an integer, which is used as an - // index to KingDanger[]. - Score KingDanger[512]; - // KingAttackWeights[PieceType] contains king attack weights by piece type - const int KingAttackWeights[PIECE_TYPE_NB] = { 0, 0, 7, 5, 4, 1 }; + const int KingAttackWeights[PIECE_TYPE_NB] = { 0, 0, 78, 56, 45, 11 }; // Penalties for enemy's safe checks - const int QueenContactCheck = 89; - const int QueenCheck = 50; - const int RookCheck = 45; - const int BishopCheck = 6; - const int KnightCheck = 14; + const int QueenCheck = 780; + const int RookCheck = 880; + const int BishopCheck = 435; + const int KnightCheck = 790; + // Threshold for lazy and space evaluation + const Value LazyThreshold = Value(1500); + const Value SpaceThreshold = Value(12222); - // init_eval_info() initializes king bitboards for given color adding - // pawn attacks. To be done at the beginning of the evaluation. + // eval_init() initializes king and attack bitboards for a given color + // adding pawn attacks. To be done at the beginning of the evaluation. template - void init_eval_info(const Position& pos, EvalInfo& ei) { + void eval_init(const Position& pos, EvalInfo& ei) { + + const Color Them = (Us == WHITE ? BLACK : WHITE); + const Square Up = (Us == WHITE ? NORTH : SOUTH); + const Square Down = (Us == WHITE ? SOUTH : NORTH); + const Bitboard LowRanks = (Us == WHITE ? Rank2BB | Rank3BB: Rank7BB | Rank6BB); + + // Find our pawns on the first two ranks, and those which are blocked + Bitboard b = pos.pieces(Us, PAWN) & (shift(pos.pieces()) | LowRanks); - const Color Them = (Us == WHITE ? BLACK : WHITE); - const Square Down = (Us == WHITE ? DELTA_S : DELTA_N); + // Squares occupied by those pawns, by our king, or controlled by enemy pawns + // are excluded from the mobility area. + ei.mobilityArea[Us] = ~(b | pos.square(Us) | ei.pe->pawn_attacks(Them)); - ei.pinnedPieces[Us] = pos.pinned_pieces(Us); - Bitboard b = ei.attackedBy[Them][KING] = pos.attacks_from(pos.square(Them)); - ei.attackedBy[Them][ALL_PIECES] |= b; - ei.attackedBy[Us][ALL_PIECES] |= ei.attackedBy[Us][PAWN] = ei.pi->pawn_attacks(Us); + // Initialise the attack bitboards with the king and pawn information + b = ei.attackedBy[Us][KING] = pos.attacks_from(pos.square(Us)); + ei.attackedBy[Us][PAWN] = ei.pe->pawn_attacks(Us); - // Init king safety tables only if we are going to use them - if (pos.non_pawn_material(Us) >= QueenValueMg) + ei.attackedBy2[Us] = b & ei.attackedBy[Us][PAWN]; + ei.attackedBy[Us][ALL_PIECES] = b | ei.attackedBy[Us][PAWN]; + + // Init our king safety tables only if we are going to use them + if (pos.non_pawn_material(Them) >= RookValueMg + KnightValueMg) { - ei.kingRing[Them] = b | shift_bb(b); - b &= ei.attackedBy[Us][PAWN]; - ei.kingAttackersCount[Us] = b ? popcount(b) : 0; - ei.kingAdjacentZoneAttacksCount[Us] = ei.kingAttackersWeight[Us] = 0; + ei.kingRing[Us] = b; + if (relative_rank(Us, pos.square(Us)) == RANK_1) + ei.kingRing[Us] |= shift(b); + + ei.kingAttackersCount[Them] = popcount(b & ei.pe->pawn_attacks(Them)); + ei.kingAdjacentZoneAttacksCount[Them] = ei.kingAttackersWeight[Them] = 0; } else - ei.kingRing[Them] = ei.kingAttackersCount[Us] = 0; + ei.kingRing[Us] = ei.kingAttackersCount[Them] = 0; } - // evaluate_pieces() assigns bonuses and penalties to the pieces of a given color + // evaluate_pieces() assigns bonuses and penalties to the pieces of a given + // color and type. - template - Score evaluate_pieces(const Position& pos, EvalInfo& ei, Score* mobility, const Bitboard* mobilityArea) { + template + Score evaluate_pieces(const Position& pos, EvalInfo& ei, Score* mobility) { - Bitboard b; - Square s; - Score score = SCORE_ZERO; - - const PieceType NextPt = (Us == WHITE ? Pt : PieceType(Pt + 1)); const Color Them = (Us == WHITE ? BLACK : WHITE); + const PieceType NextPt = (Us == WHITE ? Pt : PieceType(Pt + 1)); + const Bitboard OutpostRanks = (Us == WHITE ? Rank4BB | Rank5BB | Rank6BB + : Rank5BB | Rank4BB | Rank3BB); const Square* pl = pos.squares(Us); + Bitboard b, bb; + Square s; + Score score = SCORE_ZERO; + ei.attackedBy[Us][Pt] = 0; while ((s = *pl++) != SQ_NONE) @@ -274,45 +279,47 @@ namespace { : Pt == ROOK ? attacks_bb< ROOK>(s, pos.pieces() ^ pos.pieces(Us, ROOK, QUEEN)) : pos.attacks_from(s); - if (ei.pinnedPieces[Us] & s) + if (pos.pinned_pieces(Us) & s) b &= LineBB[pos.square(Us)][s]; + ei.attackedBy2[Us] |= ei.attackedBy[Us][ALL_PIECES] & b; ei.attackedBy[Us][ALL_PIECES] |= ei.attackedBy[Us][Pt] |= b; if (b & ei.kingRing[Them]) { ei.kingAttackersCount[Us]++; ei.kingAttackersWeight[Us] += KingAttackWeights[Pt]; - Bitboard bb = b & ei.attackedBy[Them][KING]; - if (bb) - ei.kingAdjacentZoneAttacksCount[Us] += popcount(bb); + ei.kingAdjacentZoneAttacksCount[Us] += popcount(b & ei.attackedBy[Them][KING]); } - if (Pt == QUEEN) - b &= ~( ei.attackedBy[Them][KNIGHT] - | ei.attackedBy[Them][BISHOP] - | ei.attackedBy[Them][ROOK]); + int mob = popcount(b & ei.mobilityArea[Us]); - int mob = popcount(b & mobilityArea[Us]); + mobility[Us] += MobilityBonus[Pt - 2][mob]; - mobility[Us] += MobilityBonus[Pt][mob]; + // Bonus for this piece as a king protector + score += KingProtector[Pt - 2] * distance(s, pos.square(Us)); if (Pt == BISHOP || Pt == KNIGHT) { - // Bonus for outpost square - if ( relative_rank(Us, s) >= RANK_4 - && relative_rank(Us, s) <= RANK_6 - && !(pos.pieces(Them, PAWN) & pawn_attack_span(Us, s))) - score += Outpost[Pt == BISHOP][!!(ei.attackedBy[Us][PAWN] & s)]; + // Bonus for outpost squares + bb = OutpostRanks & ~ei.pe->pawn_attacks_span(Them); + if (bb & s) + score += Outpost[Pt == BISHOP][!!(ei.attackedBy[Us][PAWN] & s)] * 2; + else + { + bb &= b & ~pos.pieces(Us); + if (bb) + score += Outpost[Pt == BISHOP][!!(ei.attackedBy[Us][PAWN] & bb)]; + } // Bonus when behind a pawn if ( relative_rank(Us, s) < RANK_5 && (pos.pieces(PAWN) & (s + pawn_push(Us)))) score += MinorBehindPawn; - // Penalty for pawns on same color square of bishop + // Penalty for pawns on the same color square as the bishop if (Pt == BISHOP) - score -= BishopPawns * ei.pi->pawns_on_same_color_squares(Us, s); + score -= BishopPawns * ei.pe->pawns_on_same_color_squares(Us, s); // An important Chess960 pattern: A cornered bishop blocked by a friendly // pawn diagonally in front of it is a very serious problem, especially @@ -321,7 +328,7 @@ namespace { && pos.is_chess960() && (s == relative_square(Us, SQ_A1) || s == relative_square(Us, SQ_H1))) { - Square d = pawn_push(Us) + (file_of(s) == FILE_A ? DELTA_E : DELTA_W); + Square d = pawn_push(Us) + (file_of(s) == FILE_A ? EAST : WEST); if (pos.piece_on(s + d) == make_piece(Us, PAWN)) score -= !pos.empty(s + d + pawn_push(Us)) ? TrappedBishopA1H1 * 4 : pos.piece_on(s + d + d) == make_piece(Us, PAWN) ? TrappedBishopA1H1 * 2 @@ -333,135 +340,162 @@ namespace { { // Bonus for aligning with enemy pawns on the same rank/file if (relative_rank(Us, s) >= RANK_5) - { - Bitboard alignedPawns = pos.pieces(Them, PAWN) & PseudoAttacks[ROOK][s]; - if (alignedPawns) - score += popcount(alignedPawns) * RookOnPawn; - } + score += RookOnPawn * popcount(pos.pieces(Them, PAWN) & PseudoAttacks[ROOK][s]); // Bonus when on an open or semi-open file - if (ei.pi->semiopen_file(Us, file_of(s))) - score += ei.pi->semiopen_file(Them, file_of(s)) ? RookOnOpenFile : RookOnSemiOpenFile; + if (ei.pe->semiopen_file(Us, file_of(s))) + score += RookOnFile[!!ei.pe->semiopen_file(Them, file_of(s))]; - // Penalize when trapped by the king, even more if king cannot castle - if (mob <= 3 && !ei.pi->semiopen_file(Us, file_of(s))) + // Penalty when trapped by the king, even more if the king cannot castle + else if (mob <= 3) { Square ksq = pos.square(Us); if ( ((file_of(ksq) < FILE_E) == (file_of(s) < file_of(ksq))) - && (rank_of(ksq) == rank_of(s) || relative_rank(Us, ksq) == RANK_1) - && !ei.pi->semiopen_side(Us, file_of(ksq), file_of(s) < file_of(ksq))) + && !ei.pe->semiopen_side(Us, file_of(ksq), file_of(s) < file_of(ksq))) score -= (TrappedRook - make_score(mob * 22, 0)) * (1 + !pos.can_castle(Us)); } } + + if (Pt == QUEEN) + { + // Penalty if any relative pin or discovered attack against the queen + Bitboard pinners; + if (pos.slider_blockers(pos.pieces(Them, ROOK, BISHOP), s, pinners)) + score -= WeakQueen; + } } if (DoTrace) Trace::add(Pt, Us, score); - // Recursively call evaluate_pieces() of next piece type until KING excluded - return score - evaluate_pieces(pos, ei, mobility, mobilityArea); + // Recursively call evaluate_pieces() of next piece type until KING is excluded + return score - evaluate_pieces(pos, ei, mobility); } template<> - Score evaluate_pieces(const Position&, EvalInfo&, Score*, const Bitboard*) { return SCORE_ZERO; } + Score evaluate_pieces(const Position&, EvalInfo&, Score*) { return SCORE_ZERO; } template<> - Score evaluate_pieces(const Position&, EvalInfo&, Score*, const Bitboard*) { return SCORE_ZERO; } + Score evaluate_pieces< true, WHITE, KING>(const Position&, EvalInfo&, Score*) { return SCORE_ZERO; } // evaluate_king() assigns bonuses and penalties to a king of a given color + const Bitboard QueenSide = FileABB | FileBBB | FileCBB | FileDBB; + const Bitboard CenterFiles = FileCBB | FileDBB | FileEBB | FileFBB; + const Bitboard KingSide = FileEBB | FileFBB | FileGBB | FileHBB; + + const Bitboard KingFlank[FILE_NB] = { + QueenSide, QueenSide, QueenSide, CenterFiles, CenterFiles, KingSide, KingSide, KingSide + }; + template Score evaluate_king(const Position& pos, const EvalInfo& ei) { - const Color Them = (Us == WHITE ? BLACK : WHITE); + const Color Them = (Us == WHITE ? BLACK : WHITE); + const Square Up = (Us == WHITE ? NORTH : SOUTH); + const Bitboard Camp = (Us == WHITE ? ~Bitboard(0) ^ Rank6BB ^ Rank7BB ^ Rank8BB + : ~Bitboard(0) ^ Rank1BB ^ Rank2BB ^ Rank3BB); - Bitboard undefended, b, b1, b2, safe; - int attackUnits; const Square ksq = pos.square(Us); + Bitboard undefended, b, b1, b2, safe, other; + int kingDanger; // King shelter and enemy pawns storm - Score score = ei.pi->king_safety(pos, ksq); + Score score = ei.pe->king_safety(pos, ksq); // Main king safety evaluation - if (ei.kingAttackersCount[Them]) + if (ei.kingAttackersCount[Them] > (1 - pos.count(Them))) { - // Find the attacked squares around the king which have no defenders - // apart from the king itself - undefended = ei.attackedBy[Them][ALL_PIECES] - & ei.attackedBy[Us][KING] - & ~( ei.attackedBy[Us][PAWN] | ei.attackedBy[Us][KNIGHT] - | ei.attackedBy[Us][BISHOP] | ei.attackedBy[Us][ROOK] - | ei.attackedBy[Us][QUEEN]); - - // Initialize the 'attackUnits' variable, which is used later on as an - // index into the KingDanger[] array. The initial value is based on the + // Find the attacked squares which are defended only by our king... + undefended = ei.attackedBy[Them][ALL_PIECES] + & ei.attackedBy[Us][KING] + & ~ei.attackedBy2[Us]; + + // ... and those which are not defended at all in the larger king ring + b = ei.attackedBy[Them][ALL_PIECES] & ~ei.attackedBy[Us][ALL_PIECES] + & ei.kingRing[Us] & ~pos.pieces(Them); + + // Initialize the 'kingDanger' variable, which will be transformed + // later into a king danger score. The initial value is based on the // number and types of the enemy's attacking pieces, the number of // attacked and undefended squares around our king and the quality of // the pawn shelter (current 'score' value). - attackUnits = std::min(72, ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them]) - + 9 * ei.kingAdjacentZoneAttacksCount[Them] - + 27 * popcount(undefended) - + 11 * !!ei.pinnedPieces[Us] - - 64 * !pos.count(Them) - - mg_value(score) / 8; - - // Analyse the enemy's safe queen contact checks. Firstly, find the - // undefended squares around the king reachable by the enemy queen... - b = undefended & ei.attackedBy[Them][QUEEN] & ~pos.pieces(Them); - if (b) - { - // ...and then remove squares not supported by another enemy piece - b &= ei.attackedBy[Them][PAWN] | ei.attackedBy[Them][KNIGHT] - | ei.attackedBy[Them][BISHOP] | ei.attackedBy[Them][ROOK] - | ei.attackedBy[Them][KING]; - - if (b) - attackUnits += QueenContactCheck * popcount(b); - } + kingDanger = ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them] + + 102 * ei.kingAdjacentZoneAttacksCount[Them] + + 201 * popcount(undefended) + + 143 * (popcount(b) + !!pos.pinned_pieces(Us)) + - 848 * !pos.count(Them) + - 9 * mg_value(score) / 8 + + 40; - // Analyse the enemy's safe distance checks for sliders and knights - safe = ~(ei.attackedBy[Us][ALL_PIECES] | pos.pieces(Them)); + // Analyse the safe enemy's checks which are possible on next move + safe = ~pos.pieces(Them); + safe &= ~ei.attackedBy[Us][ALL_PIECES] | (undefended & ei.attackedBy2[Them]); - b1 = pos.attacks_from(ksq) & safe; - b2 = pos.attacks_from(ksq) & safe; + b1 = pos.attacks_from< ROOK>(ksq); + b2 = pos.attacks_from(ksq); // Enemy queen safe checks - b = (b1 | b2) & ei.attackedBy[Them][QUEEN]; - if (b) - { - attackUnits += QueenCheck * popcount(b); - score -= Checked; - } + if ((b1 | b2) & ei.attackedBy[Them][QUEEN] & safe) + kingDanger += QueenCheck; + + // For minors and rooks, also consider the square safe if attacked twice, + // and only defended by our queen. + safe |= ei.attackedBy2[Them] + & ~(ei.attackedBy2[Us] | pos.pieces(Them)) + & ei.attackedBy[Us][QUEEN]; + + // Some other potential checks are also analysed, even from squares + // currently occupied by the opponent own pieces, as long as the square + // is not attacked by our pawns, and is not occupied by a blocked pawn. + other = ~( ei.attackedBy[Us][PAWN] + | (pos.pieces(Them, PAWN) & shift(pos.pieces(PAWN)))); + + // Enemy rooks safe and other checks + if (b1 & ei.attackedBy[Them][ROOK] & safe) + kingDanger += RookCheck; + + else if (b1 & ei.attackedBy[Them][ROOK] & other) + score -= OtherCheck; + + // Enemy bishops safe and other checks + if (b2 & ei.attackedBy[Them][BISHOP] & safe) + kingDanger += BishopCheck; + + else if (b2 & ei.attackedBy[Them][BISHOP] & other) + score -= OtherCheck; + + // Enemy knights safe and other checks + b = pos.attacks_from(ksq) & ei.attackedBy[Them][KNIGHT]; + if (b & safe) + kingDanger += KnightCheck; + + else if (b & other) + score -= OtherCheck; + + // Transform the kingDanger units into a Score, and substract it from the evaluation + if (kingDanger > 0) + score -= make_score(kingDanger * kingDanger / 4096, kingDanger / 16); + } - // Enemy rooks safe checks - b = b1 & ei.attackedBy[Them][ROOK]; - if (b) - { - attackUnits += RookCheck * popcount(b); - score -= Checked; - } + // King tropism: firstly, find squares that opponent attacks in our king flank + File kf = file_of(ksq); + b = ei.attackedBy[Them][ALL_PIECES] & KingFlank[kf] & Camp; - // Enemy bishops safe checks - b = b2 & ei.attackedBy[Them][BISHOP]; - if (b) - { - attackUnits += BishopCheck * popcount(b); - score -= Checked; - } + assert(((Us == WHITE ? b << 4 : b >> 4) & b) == 0); + assert(popcount(Us == WHITE ? b << 4 : b >> 4) == popcount(b)); - // Enemy knights safe checks - b = pos.attacks_from(ksq) & ei.attackedBy[Them][KNIGHT] & safe; - if (b) - { - attackUnits += KnightCheck * popcount(b); - score -= Checked; - } + // Secondly, add the squares which are attacked twice in that flank and + // which are not defended by our pawns. + b = (Us == WHITE ? b << 4 : b >> 4) + | (b & ei.attackedBy2[Them] & ~ei.attackedBy[Us][PAWN]); - // Finally, extract the king danger score from the KingDanger[] - // array and subtract the score from evaluation. - score -= KingDanger[std::max(std::min(attackUnits, 399), 0)]; - } + score -= CloseEnemies * popcount(b); + + // Penalty when our king is on a pawnless flank + if (!(pos.pieces(PAWN) & KingFlank[kf])) + score -= PawnlessFlank; if (DoTrace) Trace::add(KING, Us, score); @@ -470,22 +504,20 @@ namespace { } - // evaluate_threats() assigns bonuses according to the type of attacking piece - // and the type of attacked one. + // evaluate_threats() assigns bonuses according to the types of the attacking + // and the attacked pieces. template Score evaluate_threats(const Position& pos, const EvalInfo& ei) { - const Color Them = (Us == WHITE ? BLACK : WHITE); - const Square Up = (Us == WHITE ? DELTA_N : DELTA_S); - const Square Left = (Us == WHITE ? DELTA_NW : DELTA_SE); - const Square Right = (Us == WHITE ? DELTA_NE : DELTA_SW); - const Bitboard TRank2BB = (Us == WHITE ? Rank2BB : Rank7BB); - const Bitboard TRank7BB = (Us == WHITE ? Rank7BB : Rank2BB); - - enum { Minor, Rook }; + const Color Them = (Us == WHITE ? BLACK : WHITE); + const Square Up = (Us == WHITE ? NORTH : SOUTH); + const Square Left = (Us == WHITE ? NORTH_WEST : SOUTH_EAST); + const Square Right = (Us == WHITE ? NORTH_EAST : SOUTH_WEST); + const Bitboard TRank2BB = (Us == WHITE ? Rank2BB : Rank7BB); + const Bitboard TRank7BB = (Us == WHITE ? Rank7BB : Rank2BB); - Bitboard b, weak, defended, safeThreats; + Bitboard b, weak, defended, stronglyProtected, safeThreats; Score score = SCORE_ZERO; // Non-pawn enemies attacked by a pawn @@ -496,21 +528,26 @@ namespace { b = pos.pieces(Us, PAWN) & ( ~ei.attackedBy[Them][ALL_PIECES] | ei.attackedBy[Us][ALL_PIECES]); - safeThreats = (shift_bb(b) | shift_bb(b)) & weak; + safeThreats = (shift(b) | shift(b)) & weak; - if (weak ^ safeThreats) - score += ThreatenedByHangingPawn; + score += ThreatBySafePawn * popcount(safeThreats); - while (safeThreats) - score += ThreatenedByPawn[type_of(pos.piece_on(pop_lsb(&safeThreats)))]; + if (weak ^ safeThreats) + score += ThreatByHangingPawn; } - // Non-pawn enemies defended by a pawn - defended = (pos.pieces(Them) ^ pos.pieces(Them, PAWN)) & ei.attackedBy[Them][PAWN]; + // Squares strongly protected by the opponent, either because they attack the + // square with a pawn, or because they attack the square twice and we don't. + stronglyProtected = ei.attackedBy[Them][PAWN] + | (ei.attackedBy2[Them] & ~ei.attackedBy2[Us]); + + // Non-pawn enemies, strongly protected + defended = (pos.pieces(Them) ^ pos.pieces(Them, PAWN)) + & stronglyProtected; - // Enemies not defended by a pawn and under our attack + // Enemies not strongly protected and under our attack weak = pos.pieces(Them) - & ~ei.attackedBy[Them][PAWN] + & ~stronglyProtected & ei.attackedBy[Us][ALL_PIECES]; // Add a bonus according to the kind of attacking pieces @@ -518,35 +555,42 @@ namespace { { b = (defended | weak) & (ei.attackedBy[Us][KNIGHT] | ei.attackedBy[Us][BISHOP]); while (b) - score += Threat[Minor][type_of(pos.piece_on(pop_lsb(&b)))]; + { + Square s = pop_lsb(&b); + score += ThreatByMinor[type_of(pos.piece_on(s))]; + if (type_of(pos.piece_on(s)) != PAWN) + score += ThreatByRank * (int)relative_rank(Them, s); + } b = (pos.pieces(Them, QUEEN) | weak) & ei.attackedBy[Us][ROOK]; while (b) - score += Threat[Rook ][type_of(pos.piece_on(pop_lsb(&b)))]; + { + Square s = pop_lsb(&b); + score += ThreatByRook[type_of(pos.piece_on(s))]; + if (type_of(pos.piece_on(s)) != PAWN) + score += ThreatByRank * (int)relative_rank(Them, s); + } - b = weak & ~ei.attackedBy[Them][ALL_PIECES]; - if (b) - score += Hanging * popcount(b); + score += Hanging * popcount(weak & ~ei.attackedBy[Them][ALL_PIECES]); b = weak & ei.attackedBy[Us][KING]; if (b) - score += more_than_one(b) ? KingOnMany : KingOnOne; + score += ThreatByKing[more_than_one(b)]; } // Bonus if some pawns can safely push and attack an enemy piece b = pos.pieces(Us, PAWN) & ~TRank7BB; - b = shift_bb(b | (shift_bb(b & TRank2BB) & ~pos.pieces())); + b = shift(b | (shift(b & TRank2BB) & ~pos.pieces())); b &= ~pos.pieces() & ~ei.attackedBy[Them][PAWN] & (ei.attackedBy[Us][ALL_PIECES] | ~ei.attackedBy[Them][ALL_PIECES]); - b = (shift_bb(b) | shift_bb(b)) + b = (shift(b) | shift(b)) & pos.pieces(Them) & ~ei.attackedBy[Us][PAWN]; - if (b) - score += popcount(b) * PawnAttackThreat; + score += ThreatByPawnPush * popcount(b); if (DoTrace) Trace::add(THREAT, Us, score); @@ -555,23 +599,27 @@ namespace { } - // evaluate_passed_pawns() evaluates the passed pawns of the given color + // evaluate_passer_pawns() evaluates the passed pawns and candidate passed + // pawns of the given color. template - Score evaluate_passed_pawns(const Position& pos, const EvalInfo& ei) { + Score evaluate_passer_pawns(const Position& pos, const EvalInfo& ei) { const Color Them = (Us == WHITE ? BLACK : WHITE); - Bitboard b, squaresToQueen, defendedSquares, unsafeSquares; + Bitboard b, bb, squaresToQueen, defendedSquares, unsafeSquares; Score score = SCORE_ZERO; - b = ei.pi->passed_pawns(Us); + b = ei.pe->passed_pawns(Us); while (b) { Square s = pop_lsb(&b); - assert(pos.pawn_passed(Us, s)); + assert(!(pos.pieces(Them, PAWN) & forward_bb(Us, s + pawn_push(Us)))); + + bb = forward_bb(Us, s) & (ei.attackedBy[Them][ALL_PIECES] | pos.pieces(Them)); + score -= HinderPassedPawn * popcount(bb); int r = relative_rank(Us, s) - RANK_2; int rr = r * (r - 1); @@ -584,7 +632,7 @@ namespace { // Adjust bonus based on the king's proximity ebonus += distance(pos.square(Them), blockSq) * 5 * rr - - distance(pos.square(Us ), blockSq) * 2 * rr; + - distance(pos.square( Us), blockSq) * 2 * rr; // If blockSq is not the queening square then consider also a second push if (relative_rank(Us, blockSq) != RANK_8) @@ -598,7 +646,7 @@ namespace { // in the pawn's path attacked or occupied by the enemy. defendedSquares = unsafeSquares = squaresToQueen = forward_bb(Us, s); - Bitboard bb = forward_bb(Them, s) & pos.pieces(ROOK, QUEEN) & pos.attacks_from(s); + bb = forward_bb(Them, s) & pos.pieces(ROOK, QUEEN) & pos.attacks_from(s); if (!(pos.pieces(Us) & bb)) defendedSquares &= ei.attackedBy[Us][ALL_PIECES]; @@ -610,7 +658,7 @@ namespace { // assign a smaller bonus if the block square isn't attacked. int k = !unsafeSquares ? 18 : !(unsafeSquares & blockSq) ? 8 : 0; - // If the path to queen is fully defended, assign a big bonus. + // If the path to the queen is fully defended, assign a big bonus. // Otherwise assign a smaller bonus if the block square is defended. if (defendedSquares == squaresToQueen) k += 6; @@ -621,20 +669,21 @@ namespace { mbonus += k * rr, ebonus += k * rr; } else if (pos.pieces(Us) & blockSq) - mbonus += rr * 3 + r * 2 + 3, ebonus += rr + r * 2; + mbonus += rr + r * 2, ebonus += rr + r * 2; } // rr != 0 - if (pos.count(Us) < pos.count(Them)) - ebonus += ebonus / 4; + // Scale down bonus for candidate passers which need more than one + // pawn push to become passed or have a pawn in front of them. + if (!pos.pawn_passed(Us, s + pawn_push(Us)) || (pos.pieces(PAWN) & forward_bb(Us, s))) + mbonus /= 2, ebonus /= 2; score += make_score(mbonus, ebonus) + PassedFile[file_of(s)]; } if (DoTrace) - Trace::add(PASSED, Us, score * Weights[PassedPawns]); + Trace::add(PASSED, Us, score); - // Add the scores to the middlegame and endgame eval - return score * Weights[PassedPawns]; + return score; } @@ -648,11 +697,14 @@ namespace { Score evaluate_space(const Position& pos, const EvalInfo& ei) { const Color Them = (Us == WHITE ? BLACK : WHITE); + const Bitboard SpaceMask = + Us == WHITE ? CenterFiles & (Rank2BB | Rank3BB | Rank4BB) + : CenterFiles & (Rank7BB | Rank6BB | Rank5BB); // Find the safe squares for our pieces inside the area defined by - // SpaceMask[]. A square is unsafe if it is attacked by an enemy + // SpaceMask. A square is unsafe if it is attacked by an enemy // pawn, or if it is undefended and attacked by an enemy piece. - Bitboard safe = SpaceMask[Us] + Bitboard safe = SpaceMask & ~pos.pieces(Us, PAWN) & ~ei.attackedBy[Them][PAWN] & (ei.attackedBy[Us][ALL_PIECES] | ~ei.attackedBy[Them][ALL_PIECES]); @@ -665,89 +717,114 @@ namespace { // Since SpaceMask[Us] is fully on our half of the board... assert(unsigned(safe >> (Us == WHITE ? 32 : 0)) == 0); - // ...count safe + (behind & safe) with a single popcount - int bonus = popcount((Us == WHITE ? safe << 32 : safe >> 32) | (behind & safe)); - int weight = pos.count(Us) + pos.count(Us) - + pos.count(Them) + pos.count(Them); + // ...count safe + (behind & safe) with a single popcount. + int bonus = popcount((Us == WHITE ? safe << 32 : safe >> 32) | (behind & safe)); + int weight = pos.count(Us) - 2 * ei.pe->open_files(); - return make_score(bonus * weight * weight, 0); + return make_score(bonus * weight * weight / 16, 0); } // evaluate_initiative() computes the initiative correction value for the - // position, i.e. second order bonus/malus based on the known attacking/defending + // position, i.e., second order bonus/malus based on the known attacking/defending // status of the players. Score evaluate_initiative(const Position& pos, int asymmetry, Value eg) { - int kingDistance = distance(pos.square(WHITE), pos.square(BLACK)); - int pawns = pos.count(WHITE) + pos.count(BLACK); + int kingDistance = distance(pos.square(WHITE), pos.square(BLACK)) + - distance(pos.square(WHITE), pos.square(BLACK)); + bool bothFlanks = (pos.pieces(PAWN) & QueenSide) && (pos.pieces(PAWN) & KingSide); // Compute the initiative bonus for the attacking side - int initiative = 8 * (pawns + asymmetry + kingDistance - 15); + int initiative = 8 * (asymmetry + kingDistance - 17) + 12 * pos.count() + 16 * bothFlanks; // 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 - // that the endgame score will never be divided by more than two. - int value = ((eg > 0) - (eg < 0)) * std::max(initiative, -abs(eg / 2)); + // that the endgame score will never change sign after the bonus. + int value = ((eg > 0) - (eg < 0)) * std::max(initiative, -abs(eg)); return make_score(0, value); } + + // evaluate_scale_factor() computes the scale factor for the winning side + ScaleFactor evaluate_scale_factor(const Position& pos, const EvalInfo& ei, Value eg) { + + Color strongSide = eg > VALUE_DRAW ? WHITE : BLACK; + ScaleFactor sf = ei.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 (pos.opposite_bishops()) + { + // Endgame with opposite-colored bishops and no other pieces (ignoring pawns) + // is almost a draw, in case of KBP vs KB, it is even more a draw. + if ( pos.non_pawn_material(WHITE) == BishopValueMg + && pos.non_pawn_material(BLACK) == BishopValueMg) + return more_than_one(pos.pieces(PAWN)) ? ScaleFactor(31) : ScaleFactor(9); + + // Endgame with opposite-colored bishops, but also other pieces. Still + // a bit drawish, but not as drawish as with only the two bishops. + return ScaleFactor(46); + } + // Endings where weaker side can place his king in front of the opponent's + // pawns are drawish. + else if ( abs(eg) <= BishopValueEg + && pos.count(strongSide) <= 2 + && !pos.pawn_passed(~strongSide, pos.square(~strongSide))) + return ScaleFactor(37 + 7 * pos.count(strongSide)); + } + + return sf; + } + } // namespace /// evaluate() is the main evaluation function. It returns a static evaluation -/// of the position always from the point of view of the side to move. +/// of the position from the point of view of the side to move. template Value Eval::evaluate(const Position& pos) { assert(!pos.checkers()); + Score mobility[COLOR_NB] = { SCORE_ZERO, SCORE_ZERO }; + Value v; EvalInfo ei; - Score score, mobility[2] = { SCORE_ZERO, SCORE_ZERO }; - - // Initialize score by reading the incrementally updated scores included - // in the position object (material + piece square tables). - // Score is computed from the point of view of white. - score = pos.psq_score(); // Probe the material hash table - Material::Entry* me = Material::probe(pos); - score += me->imbalance(); + ei.me = Material::probe(pos); // If we have a specialized evaluation function for the current material // configuration, call it and return. - if (me->specialized_eval_exists()) - return me->evaluate(pos); + if (ei.me->specialized_eval_exists()) + return ei.me->evaluate(pos); + + // Initialize score by reading the incrementally updated scores included in + // the position object (material + piece square tables) and the material + // imbalance. Score is computed internally from the white point of view. + Score score = pos.psq_score() + ei.me->imbalance(); // Probe the pawn hash table - ei.pi = Pawns::probe(pos); - score += ei.pi->pawns_score() * Weights[PawnStructure]; + ei.pe = Pawns::probe(pos); + score += ei.pe->pawns_score(); - // Initialize attack and king safety bitboards - ei.attackedBy[WHITE][ALL_PIECES] = ei.attackedBy[BLACK][ALL_PIECES] = 0; - init_eval_info(pos, ei); - init_eval_info(pos, ei); - - // Pawns blocked or on ranks 2 and 3. Will be excluded from the mobility area - Bitboard blockedPawns[] = { - pos.pieces(WHITE, PAWN) & (shift_bb(pos.pieces()) | Rank2BB | Rank3BB), - pos.pieces(BLACK, PAWN) & (shift_bb(pos.pieces()) | Rank7BB | Rank6BB) - }; + // Early exit if score is high + v = (mg_value(score) + eg_value(score)) / 2; + if (abs(v) > LazyThreshold) + return pos.side_to_move() == WHITE ? v : -v; - // Do not include in mobility squares protected by enemy pawns, or occupied - // by our blocked pawns or king. - Bitboard mobilityArea[] = { - ~(ei.attackedBy[BLACK][PAWN] | blockedPawns[WHITE] | pos.square(WHITE)), - ~(ei.attackedBy[WHITE][PAWN] | blockedPawns[BLACK] | pos.square(BLACK)) - }; + // Initialize attack and king safety bitboards + eval_init(pos, ei); + eval_init(pos, ei); - // Evaluate pieces and mobility - score += evaluate_pieces(pos, ei, mobility, mobilityArea); - score += (mobility[WHITE] - mobility[BLACK]) * Weights[Mobility]; + // Evaluate all pieces but king and pawns + score += evaluate_pieces(pos, ei, mobility); + score += mobility[WHITE] - mobility[BLACK]; - // Evaluate kings after all other pieces because we need complete attack + // Evaluate kings after all other pieces because we need full attack // information when computing the king safety evaluation. score += evaluate_king(pos, ei) - evaluate_king(pos, ei); @@ -757,73 +834,36 @@ Value Eval::evaluate(const Position& pos) { - evaluate_threats(pos, ei); // Evaluate passed pawns, we need full attack information including king - score += evaluate_passed_pawns(pos, ei) - - evaluate_passed_pawns(pos, ei); - - // If both sides have only pawns, score for potential unstoppable pawns - if (!pos.non_pawn_material(WHITE) && !pos.non_pawn_material(BLACK)) - { - Bitboard b; - if ((b = ei.pi->passed_pawns(WHITE)) != 0) - score += int(relative_rank(WHITE, frontmost_sq(WHITE, b))) * Unstoppable; - - if ((b = ei.pi->passed_pawns(BLACK)) != 0) - score -= int(relative_rank(BLACK, frontmost_sq(BLACK, b))) * Unstoppable; - } + score += evaluate_passer_pawns(pos, ei) + - evaluate_passer_pawns(pos, ei); // Evaluate space for both sides, only during opening - if (pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK) >= 12222) - score += (evaluate_space(pos, ei) - evaluate_space(pos, ei)) * Weights[Space]; + if (pos.non_pawn_material() >= SpaceThreshold) + score += evaluate_space(pos, ei) + - evaluate_space(pos, ei); // Evaluate position potential for the winning side - score += evaluate_initiative(pos, ei.pi->pawn_asymmetry(), eg_value(score)); - - // Scale winning side if position is more drawish than it appears - Color strongSide = eg_value(score) > VALUE_DRAW ? WHITE : BLACK; - ScaleFactor sf = me->scale_factor(pos, strongSide); + score += evaluate_initiative(pos, ei.pe->pawn_asymmetry(), eg_value(score)); - // If we don't already have an unusual scale factor, check for certain - // types of endgames, and use a lower scale for those. - if ( me->game_phase() < PHASE_MIDGAME - && (sf == SCALE_FACTOR_NORMAL || sf == SCALE_FACTOR_ONEPAWN)) - { - if (pos.opposite_bishops()) - { - // Endgame with opposite-colored bishops and no other pieces (ignoring pawns) - // is almost a draw, in case of KBP vs KB is even more a draw. - if ( pos.non_pawn_material(WHITE) == BishopValueMg - && pos.non_pawn_material(BLACK) == BishopValueMg) - sf = more_than_one(pos.pieces(PAWN)) ? ScaleFactor(31) : ScaleFactor(9); - - // 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 = ScaleFactor(46 * sf / SCALE_FACTOR_NORMAL); - } - // Endings where weaker side can place his king in front of the opponent's - // pawns are drawish. - else if ( abs(eg_value(score)) <= BishopValueEg - && ei.pi->pawn_span(strongSide) <= 1 - && !pos.pawn_passed(~strongSide, pos.square(~strongSide))) - sf = ei.pi->pawn_span(strongSide) ? ScaleFactor(51) : ScaleFactor(37); - } + // Evaluate scale factor for the winning side + ScaleFactor sf = evaluate_scale_factor(pos, ei, eg_value(score)); // Interpolate between a middlegame and a (scaled by 'sf') endgame score - Value v = mg_value(score) * int(me->game_phase()) - + eg_value(score) * int(PHASE_MIDGAME - me->game_phase()) * sf / SCALE_FACTOR_NORMAL; + v = mg_value(score) * int(ei.me->game_phase()) + + eg_value(score) * int(PHASE_MIDGAME - ei.me->game_phase()) * sf / SCALE_FACTOR_NORMAL; v /= int(PHASE_MIDGAME); - // In case of tracing add all single evaluation terms + // In case of tracing add all remaining individual evaluation terms if (DoTrace) { Trace::add(MATERIAL, pos.psq_score()); - Trace::add(IMBALANCE, me->imbalance()); - Trace::add(PAWN, ei.pi->pawns_score()); - Trace::add(MOBILITY, mobility[WHITE] * Weights[Mobility] - , mobility[BLACK] * Weights[Mobility]); - Trace::add(SPACE, evaluate_space(pos, ei) * Weights[Space] - , evaluate_space(pos, ei) * Weights[Space]); + Trace::add(IMBALANCE, ei.me->imbalance()); + Trace::add(PAWN, ei.pe->pawns_score()); + Trace::add(MOBILITY, mobility[WHITE], mobility[BLACK]); + if (pos.non_pawn_material() >= SpaceThreshold) + Trace::add(SPACE, evaluate_space(pos, ei) + , evaluate_space(pos, ei)); Trace::add(TOTAL, score); } @@ -855,7 +895,7 @@ std::string Eval::trace(const Position& pos) { << " Imbalance | " << Term(IMBALANCE) << " Pawns | " << Term(PAWN) << " Knights | " << Term(KNIGHT) - << " Bishop | " << Term(BISHOP) + << " Bishops | " << Term(BISHOP) << " Rooks | " << Term(ROOK) << " Queens | " << Term(QUEEN) << " Mobility | " << Term(MOBILITY) @@ -870,19 +910,3 @@ std::string Eval::trace(const Position& pos) { return ss.str(); } - - -/// init() computes evaluation weights, usually at startup - -void Eval::init() { - - const int MaxSlope = 8700; - const int Peak = 1280000; - int t = 0; - - for (int i = 0; i < 400; ++i) - { - t = std::min(Peak, std::min(i * i * 27, t + MaxSlope)); - KingDanger[i] = make_score(t / 1000, 0) * Weights[KingSafety]; - } -}