X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fevaluate.cpp;h=f6764b18466ae4ad010f3ec57b7ed105b1314f04;hp=d533eed8c76d17172c10632c2c0cdada03a5a7a6;hb=c3af52c43bc91ef15fea6c0bedd556754412f737;hpb=5cffc032da8402df79cf6cba4238b83ff5d29f7e diff --git a/src/evaluate.cpp b/src/evaluate.cpp index d533eed8..f6764b18 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) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + Copyright (C) 2015-2018 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 @@ -29,52 +29,190 @@ #include "material.h" #include "pawns.h" -namespace { +std::atomic Eval::Contempt; - namespace Trace { +namespace Trace { - enum Term { // The first 8 entries are for PieceType - MATERIAL = 8, IMBALANCE, MOBILITY, THREAT, PASSED, SPACE, TOTAL, TERM_NB - }; + enum Tracing { NO_TRACE, TRACE }; - double scores[TERM_NB][COLOR_NB][PHASE_NB]; + enum Term { // The first 8 entries are reserved for PieceType + MATERIAL = 8, IMBALANCE, MOBILITY, THREAT, PASSED, SPACE, INITIATIVE, TOTAL, TERM_NB + }; - double to_cp(Value v) { return double(v) / PawnValueEg; } + Score scores[TERM_NB][COLOR_NB]; - void add(int idx, Color c, Score s) { - scores[idx][c][MG] = to_cp(mg_value(s)); - scores[idx][c][EG] = to_cp(eg_value(s)); - } + double to_cp(Value v) { return double(v) / PawnValueEg; } - void add(int idx, Score w, Score b = SCORE_ZERO) { - add(idx, WHITE, w); add(idx, BLACK, b); - } + void add(int idx, Color c, Score s) { + scores[idx][c] = s; + } - std::ostream& operator<<(std::ostream& os, Term t) { + void add(int idx, Score w, Score b = SCORE_ZERO) { + scores[idx][WHITE] = w; + scores[idx][BLACK] = b; + } - if (t == MATERIAL || t == IMBALANCE || t == Term(PAWN) || t == TOTAL) - os << " --- --- | --- --- | "; - else - os << std::setw(5) << scores[t][WHITE][MG] << " " - << std::setw(5) << scores[t][WHITE][EG] << " | " - << std::setw(5) << scores[t][BLACK][MG] << " " - << std::setw(5) << scores[t][BLACK][EG] << " | "; + std::ostream& operator<<(std::ostream& os, Score s) { + os << std::setw(5) << to_cp(mg_value(s)) << " " + << std::setw(5) << to_cp(eg_value(s)); + return os; + } - os << std::setw(5) << scores[t][WHITE][MG] - scores[t][BLACK][MG] << " " - << std::setw(5) << scores[t][WHITE][EG] - scores[t][BLACK][EG] << " \n"; + std::ostream& operator<<(std::ostream& os, Term t) { - return os; - } + if (t == MATERIAL || t == IMBALANCE || t == INITIATIVE || t == TOTAL) + os << " ---- ----" << " | " << " ---- ----"; + else + os << scores[t][WHITE] << " | " << scores[t][BLACK]; + + os << " | " << scores[t][WHITE] - scores[t][BLACK] << "\n"; + return os; } +} + +using namespace Trace; + +namespace { + + const Bitboard QueenSide = FileABB | FileBBB | FileCBB | FileDBB; + const Bitboard CenterFiles = FileCBB | FileDBB | FileEBB | FileFBB; + const Bitboard KingSide = FileEBB | FileFBB | FileGBB | FileHBB; + const Bitboard Center = (FileDBB | FileEBB) & (Rank4BB | Rank5BB); - using namespace Trace; + const Bitboard KingFlank[FILE_NB] = { + QueenSide, QueenSide, QueenSide, + CenterFiles, CenterFiles, + KingSide, KingSide, KingSide + }; - // Struct EvalInfo contains various information computed and collected - // by the evaluation functions. - struct EvalInfo { + // Threshold for lazy and space evaluation + const Value LazyThreshold = Value(1500); + const Value SpaceThreshold = Value(12222); + + // KingAttackWeights[PieceType] contains king attack weights by piece type + const int KingAttackWeights[PIECE_TYPE_NB] = { 0, 0, 78, 56, 45, 11 }; + + // Penalties for enemy's safe checks + const int QueenSafeCheck = 780; + const int RookSafeCheck = 880; + const int BishopSafeCheck = 435; + const int KnightSafeCheck = 790; + +#define S(mg, eg) make_score(mg, eg) + + // 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(-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 minor + // pieces if they occupy or can reach an outpost square, bigger if that + // square is supported by a pawn. + const Score Outpost[][2] = { + { S(22, 6), S(36,12) }, // Knight + { S( 9, 2), S(15, 5) } // Bishop + }; + + // 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, 31), S(39, 42), S(57, 44), S(68, 112), S(47, 120) + }; + + const Score ThreatByRook[PIECE_TYPE_NB] = { + S(0, 0), S(0, 24), S(38, 71), S(38, 61), S(0, 38), S(36, 38) + }; + + // ThreatByKing[on one/on many] contains bonuses for king attacks on + // pawns or pieces which are not pawn-defended. + const Score ThreatByKing[] = { S(3, 65), S(9, 145) }; + + // PassedRank[Rank] contains a bonus according to the rank of a passed pawn + const 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) + }; + + // 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) + }; + + // PassedDanger[Rank] contains a term to weight the passed score + const int PassedDanger[RANK_NB] = { 0, 0, 0, 2, 7, 12, 19 }; + + // KingProtector[PieceType-2] contains a penalty according to distance from king + const Score KingProtector[] = { S(3, 5), S(4, 3), S(3, 0), S(1, -1) }; + + // Assorted bonuses and penalties + const Score BishopPawns = S( 8, 12); + const Score CloseEnemies = S( 7, 0); + const Score Connectivity = S( 3, 1); + const Score Hanging = S( 52, 30); + const Score HinderPassedPawn = S( 8, 1); + const Score KnightOnQueen = S( 21, 11); + const Score LongRangedBishop = S( 22, 0); + const Score MinorBehindPawn = S( 16, 0); + const Score PawnlessFlank = S( 20, 80); + const Score RookOnPawn = S( 8, 24); + const Score SliderOnQueen = S( 42, 21); + const Score ThreatByPawnPush = S( 47, 26); + const Score ThreatByRank = S( 16, 3); + const Score ThreatBySafePawn = S(175,168); + const Score TrappedBishopA1H1 = S( 50, 50); + const Score TrappedRook = S( 92, 0); + const Score WeakQueen = S( 50, 10); + const Score WeakUnopposedPawn = S( 5, 25); + +#undef S + + // Evaluation class computes and stores attacks tables and other working data + template + class Evaluation { + + public: + Evaluation() = delete; + explicit Evaluation(const Position& p) : pos(p) {} + Evaluation& operator=(const Evaluation&) = delete; + Value value(); + + private: + template void initialize(); + template Score pieces(); + template Score king() const; + template Score threats() const; + template Score passed() const; + template Score space() const; + ScaleFactor scale_factor(Value eg) const; + Score initiative(Value eg) const; + + const Position& pos; + Material::Entry* me; + Pawns::Entry* pe; + Bitboard mobilityArea[COLOR_NB]; + Score mobility[COLOR_NB] = { SCORE_ZERO, SCORE_ZERO }; // attackedBy[color][piece type] is a bitboard representing all squares - // attacked by a given color and piece type (can be also ALL_PIECES). + // attacked by a given color and piece type. Special "piece types" which + // is also calculated is ALL_PIECES. Bitboard attackedBy[COLOR_NB][PIECE_TYPE_NB]; // attackedBy2[color] are the squares attacked by 2 pieces of a given color, @@ -82,12 +220,10 @@ namespace { // 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) - // 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. + // 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. Bitboard kingRing[COLOR_NB]; // kingAttackersCount[color] is the number of pieces of the given color @@ -106,219 +242,114 @@ 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]; - Material::Entry* me; - Pawns::Entry* pi; - }; - - #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 in the MobilityArea. - const Score MobilityBonus[][32] = { - {}, {}, - { S(-75,-76), S(-56,-54), S( -9,-26), S( -2,-10), S( 6, 5), S( 15, 11), // Knights - S( 22, 26), S( 30, 28), S( 36, 29) }, - { S(-48,-58), S(-21,-19), S( 16, -2), S( 26, 12), S( 37, 22), S( 51, 42), // Bishops - S( 54, 54), S( 63, 58), S( 65, 63), S( 71, 70), S( 79, 74), S( 81, 86), - S( 92, 90), S( 97, 94) }, - { S(-56,-78), S(-25,-18), S(-11, 26), S( -5, 55), S( -4, 70), S( -1, 81), // Rooks - S( 8,109), S( 14,120), S( 21,128), S( 23,143), S( 31,154), S( 32,160), - S( 43,165), S( 49,168), S( 59,169) }, - { S(-40,-35), S(-25,-12), S( 2, 7), S( 4, 19), S( 14, 37), S( 24, 55), // Queens - S( 25, 62), S( 40, 76), S( 43, 79), S( 47, 87), S( 54, 94), S( 56,102), - S( 60,111), S( 70,116), S( 72,118), S( 73,122), S( 75,128), S( 77,130), - S( 85,133), S( 94,136), S( 99,140), S(108,157), S(112,158), S(113,161), - S(118,174), S(119,177), S(123,191), S(128,199) } - }; - - // Outpost[knight/bishop][supported by pawn] contains bonuses for knights and - // bishops outposts, bigger if outpost piece is supported by a pawn. - const Score Outpost[][2] = { - { S(43,11), S(65,20) }, // Knights - { S(20, 3), S(29, 8) } // Bishops - }; - - // ReachableOutpost[knight/bishop][supported by pawn] contains bonuses for - // knights and bishops which can reach an outpost square in one move, bigger - // if outpost square is supported by a pawn. - const Score ReachableOutpost[][2] = { - { S(21, 5), S(35, 8) }, // Knights - { S( 8, 0), S(14, 4) } // Bishops - }; - - // RookOnFile[semiopen/open] contains bonuses for each rook when there is no - // friendly pawn on the rook file. - const Score RookOnFile[2] = { S(20, 7), S(45, 20) }; - - // ThreatBySafePawn[PieceType] contains bonuses according to which piece - // type is attacked by a pawn which is protected or is not attacked. - const Score ThreatBySafePawn[PIECE_TYPE_NB] = { - S(0, 0), S(0, 0), S(176, 139), S(131, 127), S(217, 218), S(203, 215) }; - - // Threat[by minor/by 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[][PIECE_TYPE_NB] = { - { S(0, 0), S(0, 33), S(45, 43), S(46, 47), S(72,107), S(48,118) }, // by Minor - { S(0, 0), S(0, 25), S(40, 62), S(40, 59), S( 0, 34), S(35, 48) } // by Rook - }; - - // ThreatByKing[on one/on many] contains bonuses for King attacks on - // pawns or pieces which are not pawn-defended. - const Score ThreatByKing[2] = { 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(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[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) }; - // Assorted bonuses and penalties used by evaluation - 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 CloseEnemies = S( 7, 0); - const Score SafeCheck = S(20, 20); - const Score OtherCheck = S(10, 10); - const Score ThreatByHangingPawn = S(71, 61); - const Score LooseEnemies = S( 0, 25); - const Score WeakQueen = S(35, 0); - const Score Hanging = S(48, 27); - const Score ThreatByPawnPush = S(38, 22); - const Score Unstoppable = S( 0, 20); - - // 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 - // happen in Chess960 games. - const Score TrappedBishopA1H1 = S(50, 50); - - #undef S - #undef V - - // 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[400]; - - // KingAttackWeights[PieceType] contains king attack weights by piece type - const int KingAttackWeights[PIECE_TYPE_NB] = { 0, 0, 7, 5, 4, 1 }; - - // Penalties for enemy's safe checks - const int QueenContactCheck = 89; - const int QueenCheck = 62; - const int RookCheck = 57; - const int BishopCheck = 48; - const int KnightCheck = 78; + // Evaluation::initialize() computes king and pawn attacks, and the king ring + // bitboard for a given color. This is done at the beginning of the evaluation. + template template + void Evaluation::initialize() { - // eval_init() initializes king and attack bitboards for a given color - // adding pawn attacks. To be done at the beginning of the evaluation. + const Color Them = (Us == WHITE ? BLACK : WHITE); + const Direction Up = (Us == WHITE ? NORTH : SOUTH); + const Direction Down = (Us == WHITE ? SOUTH : NORTH); + const Bitboard LowRanks = (Us == WHITE ? Rank2BB | Rank3BB: Rank7BB | Rank6BB); - template - void eval_init(const Position& pos, EvalInfo& ei) { + // Find our pawns that are blocked or on the first two ranks + 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. + mobilityArea[Us] = ~(b | pos.square(Us) | pe->pawn_attacks(Them)); - ei.pinnedPieces[Us] = pos.pinned_pieces(Us); - Bitboard b = ei.attackedBy[Them][KING]; - ei.attackedBy[Them][ALL_PIECES] |= b; - ei.attackedBy[Us][ALL_PIECES] |= ei.attackedBy[Us][PAWN] = ei.pi->pawn_attacks(Us); - ei.attackedBy2[Us] = ei.attackedBy[Us][PAWN] & ei.attackedBy[Us][KING]; + // Initialise attackedBy bitboards for kings and pawns + attackedBy[Us][KING] = pos.attacks_from(pos.square(Us)); + attackedBy[Us][PAWN] = pe->pawn_attacks(Us); + attackedBy[Us][ALL_PIECES] = attackedBy[Us][KING] | attackedBy[Us][PAWN]; + attackedBy2[Us] = attackedBy[Us][KING] & attackedBy[Us][PAWN]; - // Init king safety tables only if we are going to use them - if (pos.non_pawn_material(Us) >= QueenValueMg) + // 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] = popcount(b); - ei.kingAdjacentZoneAttacksCount[Us] = ei.kingAttackersWeight[Us] = 0; + kingRing[Us] = attackedBy[Us][KING]; + if (relative_rank(Us, pos.square(Us)) == RANK_1) + kingRing[Us] |= shift(kingRing[Us]); + + kingAttackersCount[Them] = popcount(attackedBy[Us][KING] & pe->pawn_attacks(Them)); + kingAdjacentZoneAttacksCount[Them] = kingAttackersWeight[Them] = 0; } else - ei.kingRing[Them] = ei.kingAttackersCount[Us] = 0; + kingRing[Us] = kingAttackersCount[Them] = 0; } - // 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) { - Bitboard b, bb; - Square s; - Score score = SCORE_ZERO; + // Evaluation::pieces() scores pieces of a given color and type + template template + Score Evaluation::pieces() { - const PieceType NextPt = (Us == WHITE ? Pt : PieceType(Pt + 1)); const Color Them = (Us == WHITE ? BLACK : WHITE); const Bitboard OutpostRanks = (Us == WHITE ? Rank4BB | Rank5BB | Rank6BB : Rank5BB | Rank4BB | Rank3BB); const Square* pl = pos.squares(Us); - ei.attackedBy[Us][Pt] = 0; + Bitboard b, bb; + Square s; + Score score = SCORE_ZERO; + + attackedBy[Us][Pt] = 0; while ((s = *pl++) != SQ_NONE) { // Find attacked squares, including x-ray attacks for bishops and rooks - b = Pt == BISHOP ? attacks_bb(s, pos.pieces() ^ pos.pieces(Us, QUEEN)) - : Pt == ROOK ? attacks_bb< ROOK>(s, pos.pieces() ^ pos.pieces(Us, ROOK, QUEEN)) + b = Pt == BISHOP ? attacks_bb(s, pos.pieces() ^ pos.pieces(QUEEN)) + : Pt == ROOK ? attacks_bb< ROOK>(s, pos.pieces() ^ pos.pieces(QUEEN) ^ pos.pieces(Us, ROOK)) : pos.attacks_from(s); - if (ei.pinnedPieces[Us] & s) + if (pos.blockers_for_king(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; + attackedBy2[Us] |= attackedBy[Us][ALL_PIECES] & b; + attackedBy[Us][Pt] |= b; + attackedBy[Us][ALL_PIECES] |= b; - if (b & ei.kingRing[Them]) + if (b & kingRing[Them]) { - ei.kingAttackersCount[Us]++; - ei.kingAttackersWeight[Us] += KingAttackWeights[Pt]; - ei.kingAdjacentZoneAttacksCount[Us] += popcount(b & ei.attackedBy[Them][KING]); + kingAttackersCount[Us]++; + kingAttackersWeight[Us] += KingAttackWeights[Pt]; + kingAdjacentZoneAttacksCount[Us] += popcount(b & attackedBy[Them][KING]); } - if (Pt == QUEEN) - b &= ~( ei.attackedBy[Them][KNIGHT] - | ei.attackedBy[Them][BISHOP] - | ei.attackedBy[Them][ROOK]); - int mob = popcount(b & mobilityArea[Us]); - mobility[Us] += MobilityBonus[Pt][mob]; + 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 for outpost squares - bb = OutpostRanks & ~ei.pi->pawn_attacks_span(Them); + // Bonus if piece is on an outpost square or can reach one + bb = OutpostRanks & ~pe->pawn_attacks_span(Them); if (bb & s) - score += Outpost[Pt == BISHOP][!!(ei.attackedBy[Us][PAWN] & s)]; - else - { - bb &= b & ~pos.pieces(Us); - if (bb) - score += ReachableOutpost[Pt == BISHOP][!!(ei.attackedBy[Us][PAWN] & bb)]; - } + score += Outpost[Pt == BISHOP][bool(attackedBy[Us][PAWN] & s)] * 2; + + 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)))) score += MinorBehindPawn; - // 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); + { + // Penalty according to number of pawns on the same color square as the bishop + score -= BishopPawns * pe->pawns_on_same_color_squares(Us, s); + + // 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))) + score += LongRangedBishop; + } // An important Chess960 pattern: A cornered bishop blocked by a friendly // pawn diagonally in front of it is a very serious problem, especially @@ -327,7 +358,7 @@ 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); + Direction 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 @@ -337,22 +368,19 @@ namespace { if (Pt == ROOK) { - // Bonus for aligning with enemy pawns on the same rank/file + // Bonus for aligning rook with with enemy pawns on the same rank/file if (relative_rank(Us, s) >= RANK_5) 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 += RookOnFile[!!ei.pi->semiopen_file(Them, file_of(s))]; + // Bonus for rook on an open or semi-open file + if (pe->semiopen_file(Us, file_of(s))) + score += RookOnFile[bool(pe->semiopen_file(Them, file_of(s)))]; - // Penalize when trapped by the king, even more if the king cannot castle + // 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))) + 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)); } } @@ -360,273 +388,271 @@ namespace { if (Pt == QUEEN) { // Penalty if any relative pin or discovered attack against the queen - if (pos.slider_blockers(pos.pieces(Them, ROOK, BISHOP), s)) + Bitboard queenPinners; + if (pos.slider_blockers(pos.pieces(Them, ROOK, BISHOP), s, queenPinners)) score -= WeakQueen; } } - - if (DoTrace) + if (T) Trace::add(Pt, Us, score); - // Recursively call evaluate_pieces() of next piece type until KING is excluded - return score - evaluate_pieces(pos, ei, mobility, mobilityArea); + return score; } - template<> - Score evaluate_pieces(const Position&, EvalInfo&, Score*, const Bitboard*) { return SCORE_ZERO; } - template<> - Score evaluate_pieces< true, WHITE, KING>(const Position&, EvalInfo&, Score*, const Bitboard*) { return SCORE_ZERO; } - - - // evaluate_king() assigns bonuses and penalties to a king of a given color - - const Bitboard WhiteCamp = Rank1BB | Rank2BB | Rank3BB | Rank4BB | Rank5BB; - const Bitboard BlackCamp = Rank8BB | Rank7BB | Rank6BB | Rank5BB | Rank4BB; - const Bitboard QueenSide = FileABB | FileBBB | FileCBB | FileDBB; - const Bitboard CenterFiles = FileCBB | FileDBB | FileEBB | FileFBB; - const Bitboard KingSide = FileEBB | FileFBB | FileGBB | FileHBB; - - const Bitboard KingFlank[COLOR_NB][FILE_NB] = { - { QueenSide & WhiteCamp, QueenSide & WhiteCamp, QueenSide & WhiteCamp, CenterFiles & WhiteCamp, - CenterFiles & WhiteCamp, KingSide & WhiteCamp, KingSide & WhiteCamp, KingSide & WhiteCamp }, - { QueenSide & BlackCamp, QueenSide & BlackCamp, QueenSide & BlackCamp, CenterFiles & BlackCamp, - CenterFiles & BlackCamp, KingSide & BlackCamp, KingSide & BlackCamp, KingSide & BlackCamp }, - }; - template - Score evaluate_king(const Position& pos, const EvalInfo& ei) { + // Evaluation::king() assigns bonuses and penalties to a king of a given color + template template + Score Evaluation::king() const { - const Color Them = (Us == WHITE ? BLACK : WHITE); - const Square Up = (Us == WHITE ? DELTA_N : DELTA_S); + const Color Them = (Us == WHITE ? BLACK : WHITE); + const Bitboard Camp = (Us == WHITE ? AllSquares ^ Rank6BB ^ Rank7BB ^ Rank8BB + : AllSquares ^ Rank1BB ^ Rank2BB ^ Rank3BB); - Bitboard undefended, b, b1, b2, safe, other; - int attackUnits; const Square ksq = pos.square(Us); + Bitboard weak, b, b1, b2, safe, unsafeChecks, pinned; // King shelter and enemy pawns storm - Score score = ei.pi->king_safety(pos, ksq); + Score score = pe->king_safety(pos, ksq); // Main king safety evaluation - if (ei.kingAttackersCount[Them]) + if (kingAttackersCount[Them] > 1 - pos.count(Them)) { - // Find the attacked squares which are defended only by the 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 'attackUnits' variable, which is used later on as an - // index into the KingDanger[] array. 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] - + 21 * popcount(undefended) - + 12 * (popcount(b) + !!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); - - // ...and keep squares supported by another enemy piece - attackUnits += QueenContactCheck * popcount(b & ei.attackedBy2[Them]); - - // Analyse the safe enemy's checks which are possible on next move... - safe = ~(ei.attackedBy[Us][ALL_PIECES] | pos.pieces(Them)); - - // ... and some other potential checks, only requiring the square to be - // safe from pawn-attacks, and not being occupied by a blocked pawn. - other = ~( ei.attackedBy[Us][PAWN] - | (pos.pieces(Them, PAWN) & shift_bb(pos.pieces(PAWN)))); - - b1 = pos.attacks_from(ksq); - b2 = pos.attacks_from(ksq); + int kingDanger = unsafeChecks = 0; - // Enemy queen safe checks - if ((b1 | b2) & ei.attackedBy[Them][QUEEN] & safe) - attackUnits += QueenCheck, score -= SafeCheck; + // 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]); - // For other pieces, also consider the square safe if attacked twice, - // and only defended by a queen. - safe |= ei.attackedBy2[Them] - & ~(ei.attackedBy2[Us] | pos.pieces(Them)) - & ei.attackedBy[Us][QUEEN]; + // Analyse the safe enemy's checks which are possible on next move + safe = ~pos.pieces(Them); + safe &= ~attackedBy[Us][ALL_PIECES] | (weak & attackedBy2[Them]); - // Enemy rooks safe and other checks - if (b1 & ei.attackedBy[Them][ROOK] & safe) - attackUnits += RookCheck, score -= SafeCheck; + b1 = attacks_bb(ksq, pos.pieces() ^ pos.pieces(Us, QUEEN)); + b2 = attacks_bb(ksq, pos.pieces() ^ pos.pieces(Us, QUEEN)); - else if (b1 & ei.attackedBy[Them][ROOK] & other) - score -= OtherCheck; - - // Enemy bishops safe and other checks - if (b2 & ei.attackedBy[Them][BISHOP] & safe) - attackUnits += BishopCheck, score -= SafeCheck; - - 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]; + // Enemy queen safe checks + if ((b1 | b2) & attackedBy[Them][QUEEN] & safe & ~attackedBy[Us][QUEEN]) + kingDanger += QueenSafeCheck; + + b1 &= attackedBy[Them][ROOK]; + b2 &= attackedBy[Them][BISHOP]; + + // Enemy rooks checks + if (b1 & safe) + kingDanger += RookSafeCheck; + else + unsafeChecks |= b1; + + // Enemy bishops checks + if (b2 & safe) + kingDanger += BishopSafeCheck; + else + unsafeChecks |= b2; + + // Enemy knights checks + b = pos.attacks_from(ksq) & attackedBy[Them][KNIGHT]; if (b & safe) - attackUnits += KnightCheck, score -= SafeCheck; - - else if (b & other) - score -= OtherCheck; - - // Finally, extract the king danger score from the KingDanger[] - // array and subtract the score from the evaluation. - score -= KingDanger[std::max(std::min(attackUnits, 399), 0)]; + 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 * kingAdjacentZoneAttacksCount[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); + } } - // King tropism: firstly, find squares that opponent attacks in our king flank - b = ei.attackedBy[Them][ALL_PIECES] & KingFlank[Us][file_of(ksq)]; + Bitboard kf = KingFlank[file_of(ksq)]; - assert(((Us == WHITE ? b << 4 : b >> 4) & b) == 0); - assert(popcount(Us == WHITE ? b << 4 : b >> 4) == popcount(b)); + // Penalty when our king is on a pawnless flank + if (!(pos.pieces(PAWN) & kf)) + score -= PawnlessFlank; - // 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]); + // 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]; - score -= CloseEnemies * popcount(b); + // King tropism, to anticipate slow motion attacks on our king + score -= CloseEnemies * (popcount(b1) + popcount(b2)); - if (DoTrace) + if (T) Trace::add(KING, Us, score); return score; } - // 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); + // Evaluation::threats() assigns bonuses according to the types of the + // attacking and the attacked pieces. + template template + Score Evaluation::threats() const { - enum { Minor, Rook }; + const Color Them = (Us == WHITE ? BLACK : WHITE); + const Direction Up = (Us == WHITE ? NORTH : SOUTH); + const Bitboard TRank3BB = (Us == WHITE ? Rank3BB : Rank6BB); - Bitboard b, weak, defended, safeThreats; + Bitboard b, weak, defended, nonPawnEnemies, stronglyProtected, safeThreats; Score score = SCORE_ZERO; - // Small bonus if the opponent has loose pawns or pieces - if ( (pos.pieces(Them) ^ pos.pieces(Them, QUEEN, KING)) - & ~(ei.attackedBy[Us][ALL_PIECES] | ei.attackedBy[Them][ALL_PIECES])) - score += LooseEnemies; - // Non-pawn enemies attacked by a pawn - weak = (pos.pieces(Them) ^ pos.pieces(Them, PAWN)) & ei.attackedBy[Us][PAWN]; + nonPawnEnemies = pos.pieces(Them) ^ pos.pieces(Them, PAWN); + weak = nonPawnEnemies & attackedBy[Us][PAWN]; if (weak) { - b = pos.pieces(Us, PAWN) & ( ~ei.attackedBy[Them][ALL_PIECES] - | ei.attackedBy[Us][ALL_PIECES]); - - safeThreats = (shift_bb(b) | shift_bb(b)) & weak; - - if (weak ^ safeThreats) - score += ThreatByHangingPawn; + // Our safe or protected pawns + b = pos.pieces(Us, PAWN) + & (~attackedBy[Them][ALL_PIECES] | attackedBy[Us][ALL_PIECES]); - while (safeThreats) - score += ThreatBySafePawn[type_of(pos.piece_on(pop_lsb(&safeThreats)))]; + safeThreats = pawn_attacks_bb(b) & weak; + score += ThreatBySafePawn * popcount(safeThreats); } - // Non-pawn enemies defended by a pawn - defended = (pos.pieces(Them) ^ pos.pieces(Them, PAWN)) & ei.attackedBy[Them][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. + stronglyProtected = attackedBy[Them][PAWN] + | (attackedBy2[Them] & ~attackedBy2[Us]); - // Enemies not defended by a pawn and under our attack - weak = pos.pieces(Them) - & ~ei.attackedBy[Them][PAWN] - & ei.attackedBy[Us][ALL_PIECES]; + // Non-pawn enemies, strongly protected + defended = nonPawnEnemies & stronglyProtected; - // Add a bonus according to the kind of attacking pieces + // Enemies not strongly protected and under our attack + weak = pos.pieces(Them) & ~stronglyProtected & attackedBy[Us][ALL_PIECES]; + + // Bonus according to the kind of attacking pieces if (defended | weak) { - b = (defended | weak) & (ei.attackedBy[Us][KNIGHT] | ei.attackedBy[Us][BISHOP]); + b = (defended | weak) & (attackedBy[Us][KNIGHT] | 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]; + b = (pos.pieces(Them, QUEEN) | weak) & 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); + } - score += Hanging * popcount(weak & ~ei.attackedBy[Them][ALL_PIECES]); + score += Hanging * popcount(weak & ~attackedBy[Them][ALL_PIECES]); - b = weak & ei.attackedBy[Us][KING]; + b = weak & attackedBy[Us][KING]; if (b) 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())); + // Bonus for enemy unopposed weak pawns + if (pos.pieces(Us, ROOK, QUEEN)) + score += WeakUnopposedPawn * pe->weak_unopposed(Them); - b &= ~pos.pieces() - & ~ei.attackedBy[Them][PAWN] - & (ei.attackedBy[Us][ALL_PIECES] | ~ei.attackedBy[Them][ALL_PIECES]); + // 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(); - b = (shift_bb(b) | shift_bb(b)) + // Keep only the squares which are not completely unsafe + b &= ~attackedBy[Them][PAWN] + & (attackedBy[Us][ALL_PIECES] | ~attackedBy[Them][ALL_PIECES]); + + // Bonus for safe pawn threats on the next move + b = pawn_attacks_bb(b) & pos.pieces(Them) - & ~ei.attackedBy[Us][PAWN]; + & ~attackedBy[Us][PAWN]; score += ThreatByPawnPush * popcount(b); - if (DoTrace) + // Bonus for threats on the next moves against enemy queen + if (pos.count(Them) == 1) + { + Square s = pos.square(Them); + safeThreats = mobilityArea[Us] & ~stronglyProtected; + + b = attackedBy[Us][KNIGHT] & pos.attacks_from(s); + + score += KnightOnQueen * popcount(b & safeThreats); + + b = (attackedBy[Us][BISHOP] & pos.attacks_from(s)) + | (attackedBy[Us][ROOK ] & pos.attacks_from(s)); + + score += SliderOnQueen * popcount(b & safeThreats & 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); return score; } + // Evaluation::passed() evaluates the passed pawns and candidate passed + // pawns of the given color. - // evaluate_passed_pawns() evaluates the passed pawns of the given color + template template + Score Evaluation::passed() const { - template - Score evaluate_passed_pawns(const Position& pos, const EvalInfo& ei) { + const Color Them = (Us == WHITE ? BLACK : WHITE); + const Direction Up = (Us == WHITE ? NORTH : SOUTH); - const Color Them = (Us == WHITE ? BLACK : WHITE); + auto king_proximity = [&](Color c, Square s) { + return std::min(distance(pos.square(c), s), 5); + }; - Bitboard b, squaresToQueen, defendedSquares, unsafeSquares; + Bitboard b, bb, squaresToQueen, defendedSquares, unsafeSquares; Score score = SCORE_ZERO; - b = ei.pi->passed_pawns(Us); + b = pe->passed_pawns(Us); while (b) { Square s = pop_lsb(&b); - assert(pos.pawn_passed(Us, s)); - assert(!(pos.pieces(PAWN) & forward_bb(Us, s))); + 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) - RANK_2; - int rr = r * (r - 1); + int r = relative_rank(Us, s); + int w = PassedDanger[r]; - Value mbonus = Passed[MG][r], ebonus = Passed[EG][r]; + Score bonus = PassedRank[r]; - if (rr) + if (w) { - Square blockSq = s + pawn_push(Us); + Square blockSq = s + Up; // Adjust bonus based on the king's proximity - ebonus += distance(pos.square(Them), blockSq) * 5 * rr - - distance(pos.square(Us ), blockSq) * 2 * rr; + bonus += make_score(0, ( king_proximity(Them, blockSq) * 5 + - king_proximity(Us, blockSq) * 2) * w); // If blockSq is not the queening square then consider also a second push - if (relative_rank(Us, blockSq) != RANK_8) - ebonus -= distance(pos.square(Us), blockSq + pawn_push(Us)) * rr; + if (r != RANK_7) + bonus -= make_score(0, king_proximity(Us, blockSq + Up) * w); // If the pawn is free to advance, then increase the bonus if (pos.empty(blockSq)) @@ -634,19 +660,19 @@ namespace { // If there is a rook or queen attacking/defending the pawn from behind, // consider all the squaresToQueen. Otherwise consider only the squares // in the pawn's path attacked or occupied by the enemy. - defendedSquares = unsafeSquares = squaresToQueen = forward_bb(Us, s); + defendedSquares = unsafeSquares = squaresToQueen = forward_file_bb(Us, s); - Bitboard bb = forward_bb(Them, s) & pos.pieces(ROOK, QUEEN) & pos.attacks_from(s); + bb = forward_file_bb(Them, s) & pos.pieces(ROOK, QUEEN) & pos.attacks_from(s); if (!(pos.pieces(Us) & bb)) - defendedSquares &= ei.attackedBy[Us][ALL_PIECES]; + defendedSquares &= attackedBy[Us][ALL_PIECES]; if (!(pos.pieces(Them) & bb)) - unsafeSquares &= ei.attackedBy[Them][ALL_PIECES] | pos.pieces(Them); + unsafeSquares &= attackedBy[Them][ALL_PIECES] | pos.pieces(Them); // If there aren't any enemy attacks, assign a big bonus. Otherwise // assign a smaller bonus if the block square isn't attacked. - int k = !unsafeSquares ? 18 : !(unsafeSquares & blockSq) ? 8 : 0; + int k = !unsafeSquares ? 20 : !(unsafeSquares & blockSq) ? 9 : 0; // If the path to the queen is fully defended, assign a big bonus. // Otherwise assign a smaller bonus if the block square is defended. @@ -656,93 +682,114 @@ namespace { else if (defendedSquares & blockSq) k += 4; - mbonus += k * rr, ebonus += k * rr; + bonus += make_score(k * w, k * w); } else if (pos.pieces(Us) & blockSq) - mbonus += rr + r * 2, ebonus += rr + r * 2; + bonus += make_score(w + r * 2, w + r * 2); } // rr != 0 - score += make_score(mbonus, ebonus) + PassedFile[file_of(s)]; + // 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 + Up) + || (pos.pieces(PAWN) & forward_file_bb(Us, s))) + bonus = bonus / 2; + + score += bonus + PassedFile[file_of(s)]; } - if (DoTrace) + if (T) Trace::add(PASSED, Us, score); - // Add the scores to the middlegame and endgame eval return score; } - // evaluate_space() computes the space evaluation for a given side. The + // Evaluation::space() computes the space evaluation for a given side. The // space evaluation is a simple bonus based on the number of safe squares // available for minor pieces on the central four files on ranks 2--4. Safe // squares one, two or three squares behind a friendly pawn are counted // twice. Finally, the space bonus is multiplied by a weight. The aim is to // improve play on game opening. - template - Score evaluate_space(const Position& pos, const EvalInfo& ei) { + + template template + Score Evaluation::space() const { const Color Them = (Us == WHITE ? BLACK : WHITE); const Bitboard SpaceMask = - Us == WHITE ? (FileCBB | FileDBB | FileEBB | FileFBB) & (Rank2BB | Rank3BB | Rank4BB) - : (FileCBB | FileDBB | FileEBB | FileFBB) & (Rank7BB | Rank6BB | Rank5BB); + Us == WHITE ? CenterFiles & (Rank2BB | Rank3BB | Rank4BB) + : CenterFiles & (Rank7BB | Rank6BB | Rank5BB); + + if (pos.non_pawn_material() < SpaceThreshold) + return SCORE_ZERO; // Find the safe squares for our pieces inside the area defined by // 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 & ~pos.pieces(Us, PAWN) - & ~ei.attackedBy[Them][PAWN] - & (ei.attackedBy[Us][ALL_PIECES] | ~ei.attackedBy[Them][ALL_PIECES]); + & ~attackedBy[Them][PAWN] + & (attackedBy[Us][ALL_PIECES] | ~attackedBy[Them][ALL_PIECES]); // Find all squares which are at most three squares behind some friendly pawn Bitboard behind = pos.pieces(Us, PAWN); behind |= (Us == WHITE ? behind >> 8 : behind << 8); behind |= (Us == WHITE ? behind >> 16 : behind << 16); - // Since SpaceMask[Us] is fully on our half of the board... - assert(unsigned(safe >> (Us == WHITE ? 32 : 0)) == 0); + int bonus = popcount(safe) + popcount(behind & safe); + int weight = pos.count(Us) - 2 * pe->open_files(); - // ...count safe + (behind & safe) with a single popcount - int bonus = popcount((Us == WHITE ? safe << 32 : safe >> 32) | (behind & safe)); - bonus = std::min(16, bonus); - int weight = pos.count(Us); + Score score = make_score(bonus * weight * weight / 16, 0); - return make_score(bonus * weight * weight / 22, 0); + if (T) + Trace::add(SPACE, Us, score); + + return score; } - // evaluate_initiative() computes the initiative correction value for the - // 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) { + // Evaluation::initiative() computes the initiative correction value + // for the position. It is a second order bonus/malus based on the + // known attacking/defending status of the players. - int kingDistance = distance(pos.square(WHITE), pos.square(BLACK)) - - distance(pos.square(WHITE), pos.square(BLACK)); - int pawns = pos.count(WHITE) + pos.count(BLACK); + template + Score Evaluation::initiative(Value eg) const { + + int outflanking = distance(pos.square(WHITE), pos.square(BLACK)) + - distance(pos.square(WHITE), pos.square(BLACK)); + + bool pawnsOnBothFlanks = (pos.pieces(PAWN) & QueenSide) + && (pos.pieces(PAWN) & KingSide); // Compute the initiative bonus for the attacking side - int initiative = 8 * (asymmetry + kingDistance - 15) + 12 * pawns; + int complexity = 8 * outflanking + + 8 * pe->pawn_asymmetry() + + 12 * pos.count() + + 16 * pawnsOnBothFlanks + -136 ; // 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 v = ((eg > 0) - (eg < 0)) * std::max(complexity, -abs(eg)); + + if (T) + Trace::add(INITIATIVE, make_score(0, v)); - return make_score(0, value); + return make_score(0, v); } - // evaluate_scale_factor() computes the scale factor for the winning side - ScaleFactor evaluate_scale_factor(const Position& pos, const EvalInfo& ei, Value eg) { + // Evaluation::scale_factor() computes the scale factor for the winning side + + template + ScaleFactor Evaluation::scale_factor(Value eg) const { Color strongSide = eg > VALUE_DRAW ? WHITE : BLACK; - ScaleFactor sf = ei.me->scale_factor(pos, strongSide); + 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 ( ei.me->game_phase() < PHASE_MIDGAME - && (sf == SCALE_FACTOR_NORMAL || sf == SCALE_FACTOR_ONEPAWN)) + if (sf == SCALE_FACTOR_NORMAL || sf == SCALE_FACTOR_ONEPAWN) { if (pos.opposite_bishops()) { @@ -750,139 +797,106 @@ namespace { // 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) - sf = more_than_one(pos.pieces(PAWN)) ? ScaleFactor(31) : ScaleFactor(9); + sf = more_than_one(pos.pieces(PAWN)) ? 31 : 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 = 46; } - // Endings where weaker side can place his king in front of the opponent's + // 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 = ScaleFactor(37 + 7 * pos.count(strongSide)); + sf = 37 + 7 * pos.count(strongSide); } - return sf; + return ScaleFactor(sf); } -} // namespace + // Evaluation::value() is the main function of the class. It computes the various + // parts of the evaluation and returns the value of the position from the point + // of view of the side to move. -/// evaluate() is the main evaluation function. It returns a static evaluation -/// of the position from the point of view of the side to move. + template + Value Evaluation::value() { -template -Value Eval::evaluate(const Position& pos) { + assert(!pos.checkers()); - assert(!pos.checkers()); + // Probe the material hash table + me = Material::probe(pos); - EvalInfo ei; - Score score, mobility[COLOR_NB] = { SCORE_ZERO, SCORE_ZERO }; + // 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); - // Initialize score by reading the incrementally updated scores included in - // the position object (material + piece square tables). Score is computed - // internally from the white point of view. - score = pos.psq_score(); + // 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() + me->imbalance() + Eval::Contempt; - // Probe the material hash table - ei.me = Material::probe(pos); - score += ei.me->imbalance(); + // Probe the pawn hash table + pe = Pawns::probe(pos); + score += pe->pawn_score(WHITE) - pe->pawn_score(BLACK); - // If we have a specialized evaluation function for the current material - // configuration, call it and return. - if (ei.me->specialized_eval_exists()) - return ei.me->evaluate(pos); + // Early exit if score is high + Value v = (mg_value(score) + eg_value(score)) / 2; + if (abs(v) > LazyThreshold) + return pos.side_to_move() == WHITE ? v : -v; - // Probe the pawn hash table - ei.pi = Pawns::probe(pos); - score += ei.pi->pawns_score(); + // Main evaluation begins here - // Initialize attack and king safety bitboards - ei.attackedBy[WHITE][ALL_PIECES] = ei.attackedBy[BLACK][ALL_PIECES] = 0; - ei.attackedBy[WHITE][KING] = pos.attacks_from(pos.square(WHITE)); - ei.attackedBy[BLACK][KING] = pos.attacks_from(pos.square(BLACK)); - eval_init(pos, ei); - eval_init(pos, ei); + initialize(); + initialize(); - // 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) - }; + // Pieces should be evaluated first (populate attack tables) + score += pieces() - pieces() + + pieces() - pieces() + + pieces() - pieces() + + pieces() - pieces(); - // Do not include in mobility area 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)) - }; + score += mobility[WHITE] - mobility[BLACK]; - // Evaluate all pieces but king and pawns - score += evaluate_pieces(pos, ei, mobility, mobilityArea); - score += mobility[WHITE] - mobility[BLACK]; + score += king< WHITE>() - king< BLACK>() + + threats() - threats() + + passed< WHITE>() - passed< BLACK>() + + space< WHITE>() - space< BLACK>(); - // 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); + score += initiative(eg_value(score)); - // Evaluate tactical threats, we need full attack information including king - score += evaluate_threats(pos, ei) - - evaluate_threats(pos, ei); + // Interpolate between a middlegame and a (scaled by 'sf') endgame score + ScaleFactor sf = scale_factor(eg_value(score)); + v = mg_value(score) * int(me->game_phase()) + + eg_value(score) * int(PHASE_MIDGAME - me->game_phase()) * sf / SCALE_FACTOR_NORMAL; - // Evaluate passed pawns, we need full attack information including king - score += evaluate_passed_pawns(pos, ei) - - evaluate_passed_pawns(pos, ei); + v /= int(PHASE_MIDGAME); - // 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 += Unstoppable * int(relative_rank(WHITE, frontmost_sq(WHITE, b))); + // In case of tracing add all remaining individual evaluation terms + if (T) + { + Trace::add(MATERIAL, pos.psq_score()); + Trace::add(IMBALANCE, me->imbalance()); + Trace::add(PAWN, pe->pawn_score(WHITE), pe->pawn_score(BLACK)); + Trace::add(MOBILITY, mobility[WHITE], mobility[BLACK]); + Trace::add(TOTAL, score); + } - if ((b = ei.pi->passed_pawns(BLACK)) != 0) - score -= Unstoppable * int(relative_rank(BLACK, frontmost_sq(BLACK, b))); + return (pos.side_to_move() == WHITE ? v : -v) // Side to move point of view + + Eval::Tempo; } - // 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); - - // Evaluate position potential for the winning side - score += evaluate_initiative(pos, ei.pi->pawn_asymmetry(), eg_value(score)); - - // 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(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 remaining individual evaluation terms - if (DoTrace) - { - Trace::add(MATERIAL, pos.psq_score()); - Trace::add(IMBALANCE, ei.me->imbalance()); - Trace::add(PAWN, ei.pi->pawns_score()); - Trace::add(MOBILITY, mobility[WHITE], mobility[BLACK]); - Trace::add(SPACE, evaluate_space(pos, ei) - , evaluate_space(pos, ei)); - Trace::add(TOTAL, score); - } +} // namespace - return (pos.side_to_move() == WHITE ? v : -v) + Eval::Tempo; // Side to move point of view -} -// Explicit template instantiations -template Value Eval::evaluate(const Position&); -template Value Eval::evaluate(const Position&); +/// evaluate() is the evaluator for the outer world. It returns a static +/// evaluation of the position from the point of view of the side to move. + +Value Eval::evaluate(const Position& pos) { + return Evaluation(pos).value(); +} /// trace() is like evaluate(), but instead of returning a value, it returns @@ -893,46 +907,34 @@ std::string Eval::trace(const Position& pos) { std::memset(scores, 0, sizeof(scores)); - Value v = evaluate(pos); - v = pos.side_to_move() == WHITE ? v : -v; // White's point of view + Eval::Contempt = SCORE_ZERO; // Reset any dynamic contempt + + Value v = Evaluation(pos).value(); + + v = pos.side_to_move() == WHITE ? v : -v; // Trace scores are from white's point of view std::stringstream ss; ss << std::showpoint << std::noshowpos << std::fixed << std::setprecision(2) - << " Eval term | White | Black | Total \n" - << " | MG EG | MG EG | MG EG \n" - << "----------------+-------------+-------------+-------------\n" - << " Material | " << Term(MATERIAL) - << " Imbalance | " << Term(IMBALANCE) - << " Pawns | " << Term(PAWN) - << " Knights | " << Term(KNIGHT) - << " Bishop | " << Term(BISHOP) - << " Rooks | " << Term(ROOK) - << " Queens | " << Term(QUEEN) - << " Mobility | " << Term(MOBILITY) - << " King safety | " << Term(KING) - << " Threats | " << Term(THREAT) - << " Passed pawns | " << Term(PASSED) - << " Space | " << Term(SPACE) - << "----------------+-------------+-------------+-------------\n" - << " Total | " << Term(TOTAL); - - ss << "\nTotal Evaluation: " << to_cp(v) << " (white side)\n"; + << " Term | White | Black | Total \n" + << " | MG EG | MG EG | MG EG \n" + << " ------------+-------------+-------------+------------\n" + << " Material | " << Term(MATERIAL) + << " Imbalance | " << Term(IMBALANCE) + << " Initiative | " << Term(INITIATIVE) + << " Pawns | " << Term(PAWN) + << " Knights | " << Term(KNIGHT) + << " Bishops | " << Term(BISHOP) + << " Rooks | " << Term(ROOK) + << " Queens | " << Term(QUEEN) + << " Mobility | " << Term(MOBILITY) + << " King safety | " << Term(KING) + << " Threats | " << Term(THREAT) + << " Passed | " << Term(PASSED) + << " Space | " << Term(SPACE) + << " ------------+-------------+-------------+------------\n" + << " Total | " << Term(TOTAL); + + ss << "\nTotal evaluation: " << to_cp(v) << " (white side)\n"; return ss.str(); } - - -/// init() computes evaluation weights, usually at startup - -void Eval::init() { - - const int MaxSlope = 322; - const int Peak = 47410; - int t = 0; - - for (int i = 0; i < 400; ++i) - { - t = std::min(Peak, std::min(i * i - 16, t + MaxSlope)); - KingDanger[i] = make_score(t * 268 / 7700, 0); - } -}