X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fevaluate.cpp;h=a0e22516002acbd0b2aebf8eb66e50918f6dec25;hp=57bbfe09d87f6d97a4a940a3be85930d0f9641fb;hb=766fb9c67da48c696e9444a3a46c531786172256;hpb=553ead429d94b6314ff14aa3eb724f47987e5a52 diff --git a/src/evaluate.cpp b/src/evaluate.cpp index 57bbfe09..a0e22516 100644 --- a/src/evaluate.cpp +++ b/src/evaluate.cpp @@ -17,10 +17,10 @@ along with this program. If not, see . */ +#include #include #include #include -#include #include "bitcount.h" #include "evaluate.h" @@ -76,7 +76,7 @@ namespace { namespace Tracing { enum Terms { // First 8 entries are for PieceType - PST = 8, IMBALANCE, MOBILITY, THREAT, PASSED, SPACE, TOTAL, TERMS_NB + MATERIAL = 8, IMBALANCE, MOBILITY, THREAT, PASSED, SPACE, TOTAL, TERMS_NB }; Score terms[COLOR_NB][TERMS_NB]; @@ -89,38 +89,30 @@ namespace { std::string do_trace(const Position& pos); } - // Evaluation weights, initialized from UCI options - enum { Mobility, PawnStructure, PassedPawns, Space, KingDangerUs, KingDangerThem }; - Score Weights[6]; + // Evaluation weights, indexed by evaluation term + enum { Mobility, PawnStructure, PassedPawns, Space, KingSafety }; + const struct Weight { int mg, eg; } Weights[] = { + {289, 344}, {233, 201}, {221, 273}, {46, 0}, {318, 0} + }; typedef Value V; #define S(mg, eg) make_score(mg, eg) - // Internal evaluation weights. These are applied on top of the evaluation - // weights read from UCI parameters. The purpose is to be able to change - // the evaluation weights while keeping the default values of the UCI - // parameters at 100, which looks prettier. - // - // Values modified by Joona Kiiski - const Score WeightsInternal[] = { - S(289, 344), S(233, 201), S(221, 273), S(46, 0), S(271, 0), S(307, 0) - }; - // MobilityBonus[PieceType][attacked] contains bonuses for middle and end // game, indexed by piece type and number of attacked squares not occupied by // friendly pieces. const Score MobilityBonus[][32] = { {}, {}, - { S(-35,-30), S(-22,-20), S(-9,-10), S( 3, 0), S(15, 10), S(27, 20), // Knights + { S(-65,-50), S(-42,-30), S(-9,-10), S( 3, 0), S(15, 10), S(27, 20), // Knights S( 37, 28), S( 42, 31), S(44, 33) }, - { S(-22,-27), S( -8,-13), S( 6, 1), S(20, 15), S(34, 29), S(48, 43), // Bishops + { S(-52,-47), S(-28,-23), S( 6, 1), S(20, 15), S(34, 29), S(48, 43), // Bishops S( 60, 55), S( 68, 63), S(74, 68), S(77, 72), S(80, 75), S(82, 77), S( 84, 79), S( 86, 81) }, - { S(-17,-33), S(-11,-16), S(-5, 0), S( 1, 16), S( 7, 32), S(13, 48), // Rooks + { S(-47,-53), S(-31,-26), S(-5, 0), S( 1, 16), S( 7, 32), S(13, 48), // Rooks S( 18, 64), S( 22, 80), S(26, 96), S(29,109), S(31,115), S(33,119), S( 35,122), S( 36,123), S(37,124) }, - { S(-12,-20), S( -8,-13), S(-5, -7), S(-2, -1), S( 1, 5), S( 4, 11), // Queens - S( 7, 17), S( 10, 23), S(13, 29), S(16, 34), S(18, 38), S(20, 40), + { S(-42,-40), S(-28,-23), S(-5, -7), S( 0, 0), S( 6, 10), S(11, 19), // Queens + S( 13, 29), S( 18, 38), S(20, 40), S(21, 41), S(22, 41), S(22, 41), S( 22, 41), S( 23, 41), S(24, 41), S(25, 41), S(25, 41), S(25, 41), S( 25, 41), S( 25, 41), S(25, 41), S(25, 41), S(25, 41), S(25, 41), S( 25, 41), S( 25, 41), S(25, 41), S(25, 41) } @@ -155,29 +147,27 @@ namespace { // ThreatenedByPawn[PieceType] contains a penalty according to which piece // type is attacked by an enemy pawn. const Score ThreatenedByPawn[] = { - S(0, 0), S(0, 0), S(56, 70), S(56, 70), S(76, 99), S(86, 118) + S(0, 0), S(0, 0), S(80, 119), S(80, 119), S(117, 199), S(127, 218) }; - #undef S - - const Score Tempo = make_score(24, 11); - const Score RookOn7th = make_score(11, 20); - const Score QueenOn7th = make_score( 3, 8); - const Score RookOnPawn = make_score(10, 28); - const Score QueenOnPawn = make_score( 4, 20); - const Score RookOpenFile = make_score(43, 21); - const Score RookSemiopenFile = make_score(19, 10); - const Score BishopPawns = make_score( 8, 12); - const Score KnightPawns = make_score( 8, 4); - const Score MinorBehindPawn = make_score(16, 0); - const Score UndefendedMinor = make_score(25, 10); - const Score TrappedRook = make_score(90, 0); - const Score Unstoppable = make_score( 0, 20); + // Assorted bonuses and penalties used by evaluation + const Score KingOnPawnOne = S(0 , 64); + const Score KingOnPawnMany = S(0 ,128); + const Score RookOnPawn = S(10, 28); + const Score RookOpenFile = S(43, 21); + const Score RookSemiOpenFile = 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(23, 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 = make_score(50, 50); + const Score TrappedBishopA1H1 = S(50, 50); + + #undef S // SpaceMask[Color] contains the area of the board which is considered // by the space evaluation. In the middlegame, each side is given a bonus @@ -204,196 +194,17 @@ namespace { const int BishopCheck = 2; const int KnightCheck = 3; - // KingDanger[Color][attackUnits] contains the actual king danger weighted - // scores, indexed by color and by a calculated integer number. - Score KingDanger[COLOR_NB][128]; - - // Function prototypes - template - Value do_evaluate(const Position& pos); - - template - void init_eval_info(const Position& pos, EvalInfo& ei); - - template - Score evaluate_pieces(const Position& pos, EvalInfo& ei, Score* mobility); - - template - Score evaluate_king(const Position& pos, const EvalInfo& ei); - - template - Score evaluate_threats(const Position& pos, const EvalInfo& ei); - - template - Score evaluate_passed_pawns(const Position& pos, const EvalInfo& ei); - - template - int evaluate_space(const Position& pos, const EvalInfo& ei); - - Score evaluate_unstoppable_pawns(const Position& pos, Color us, const EvalInfo& ei); - - Value interpolate(const Score& v, Phase ph, ScaleFactor sf); - Score apply_weight(Score v, Score w); - Score weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight); -} - - -namespace Eval { - - /// evaluate() is the main evaluation function. It always computes two - /// values, an endgame score and a middlegame score, and interpolates - /// between them based on the remaining material. - - Value evaluate(const Position& pos) { - return do_evaluate(pos); - } - - - /// trace() is like evaluate(), but instead of returning a value, it returns - /// a string (suitable for outputting to stdout) that contains the detailed - /// descriptions and values of each evaluation term. It's mainly used for - /// debugging. - std::string trace(const Position& pos) { - return Tracing::do_trace(pos); - } - - - /// init() computes evaluation weights from the corresponding UCI parameters - /// and setup king tables. - - void init() { - - Weights[Mobility] = weight_option("Mobility (Midgame)", "Mobility (Endgame)", WeightsInternal[Mobility]); - Weights[PawnStructure] = weight_option("Pawn Structure (Midgame)", "Pawn Structure (Endgame)", WeightsInternal[PawnStructure]); - Weights[PassedPawns] = weight_option("Passed Pawns (Midgame)", "Passed Pawns (Endgame)", WeightsInternal[PassedPawns]); - Weights[Space] = weight_option("Space", "Space", WeightsInternal[Space]); - Weights[KingDangerUs] = weight_option("Cowardice", "Cowardice", WeightsInternal[KingDangerUs]); - Weights[KingDangerThem] = weight_option("Aggressiveness", "Aggressiveness", WeightsInternal[KingDangerThem]); - - const int MaxSlope = 30; - const int Peak = 1280; - - for (int t = 0, i = 1; i < 100; ++i) - { - t = std::min(Peak, std::min(int(0.4 * i * i), t + MaxSlope)); - - KingDanger[1][i] = apply_weight(make_score(t, 0), Weights[KingDangerUs]); - KingDanger[0][i] = apply_weight(make_score(t, 0), Weights[KingDangerThem]); - } - } - -} // namespace Eval - - -namespace { - -template -Value do_evaluate(const Position& pos) { - - assert(!pos.checkers()); - - EvalInfo ei; - Score score, mobility[2] = { SCORE_ZERO, SCORE_ZERO }; - Thread* thisThread = pos.this_thread(); - - // Initialize score by reading the incrementally updated scores included - // in the position object (material + piece square tables) and adding a - // Tempo bonus. Score is computed from the point of view of white. - score = pos.psq_score() + (pos.side_to_move() == WHITE ? Tempo : -Tempo); - - // Probe the material hash table - ei.mi = Material::probe(pos, thisThread->materialTable, thisThread->endgames); - score += ei.mi->material_value(); - - // If we have a specialized evaluation function for the current material - // configuration, call it and return. - if (ei.mi->specialized_eval_exists()) - return ei.mi->evaluate(pos); - - // Probe the pawn hash table - ei.pi = Pawns::probe(pos, thisThread->pawnsTable); - score += apply_weight(ei.pi->pawns_value(), Weights[PawnStructure]); - - // Initialize attack and king safety bitboards - init_eval_info(pos, ei); - init_eval_info(pos, ei); - - // Evaluate pieces and mobility - score += evaluate_pieces(pos, ei, mobility) - - evaluate_pieces(pos, ei, mobility); - - score += apply_weight(mobility[WHITE] - mobility[BLACK], Weights[Mobility]); - - // Evaluate kings after all other pieces because we need complete attack - // information when computing the king safety evaluation. - score += evaluate_king(pos, ei) - - evaluate_king(pos, ei); - - // Evaluate tactical threats, we need full attack information including king - score += evaluate_threats(pos, ei) - - 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 one side has only a king, score for potential unstoppable pawns - if (!pos.non_pawn_material(WHITE) || !pos.non_pawn_material(BLACK)) - score += evaluate_unstoppable_pawns(pos, WHITE, ei) - - evaluate_unstoppable_pawns(pos, BLACK, ei); - - // Evaluate space for both sides, only in middlegame - if (ei.mi->space_weight()) - { - int s = evaluate_space(pos, ei) - evaluate_space(pos, ei); - score += apply_weight(s * ei.mi->space_weight(), Weights[Space]); - } - - // Scale winning side if position is more drawish than it appears - ScaleFactor sf = eg_value(score) > VALUE_DRAW ? ei.mi->scale_factor(pos, WHITE) - : ei.mi->scale_factor(pos, BLACK); - - // If we don't already have an unusual scale factor, check for opposite - // colored bishop endgames, and use a lower scale for those. - if ( ei.mi->game_phase() < PHASE_MIDGAME - && pos.opposite_bishops() - && (sf == SCALE_FACTOR_NORMAL || sf == SCALE_FACTOR_ONEPAWN)) - { - // Ignoring any pawns, do both sides only have a single bishop and no - // other pieces? - if ( pos.non_pawn_material(WHITE) == BishopValueMg - && pos.non_pawn_material(BLACK) == BishopValueMg) - { - // Check for KBP vs KB with only a single pawn that is almost - // certainly a draw or at least two pawns. - bool one_pawn = (pos.count(WHITE) + pos.count(BLACK) == 1); - sf = one_pawn ? ScaleFactor(8) : ScaleFactor(32); - } - else - // Endgame with opposite-colored bishops, but also other pieces. Still - // a bit drawish, but not as drawish as with only the two bishops. - sf = ScaleFactor(50 * sf / SCALE_FACTOR_NORMAL); - } + // KingDanger[attackUnits] contains the actual king danger weighted + // scores, indexed by a calculated integer number. + Score KingDanger[128]; - Value v = interpolate(score, ei.mi->game_phase(), sf); + const int ScalePawnSpan[2] = { 38, 56 }; - // In case of tracing add all single evaluation contributions for both white and black - if (Trace) - { - Tracing::add_term(Tracing::PST, pos.psq_score()); - Tracing::add_term(Tracing::IMBALANCE, ei.mi->material_value()); - Tracing::add_term(PAWN, ei.pi->pawns_value()); - Score w = ei.mi->space_weight() * evaluate_space(pos, ei); - Score b = ei.mi->space_weight() * evaluate_space(pos, ei); - Tracing::add_term(Tracing::SPACE, apply_weight(w, Weights[Space]), apply_weight(b, Weights[Space])); - Tracing::add_term(Tracing::TOTAL, score); - Tracing::ei = ei; - Tracing::sf = sf; + // apply_weight() weighs score 'v' by weight 'w' trying to prevent overflow + Score apply_weight(Score v, const Weight& w) { + return make_score(mg_value(v) * w.mg / 256, eg_value(v) * w.eg / 256); } - return pos.side_to_move() == WHITE ? v : -v; -} - // init_eval_info() initializes king bitboards for given color adding // pawn attacks. To be done at the beginning of the evaluation. @@ -407,7 +218,7 @@ Value do_evaluate(const Position& pos) { ei.pinnedPieces[Us] = pos.pinned_pieces(Us); Bitboard b = ei.attackedBy[Them][KING] = pos.attacks_from(pos.king_square(Them)); - ei.attackedBy[Us][PAWN] = ei.pi->pawn_attacks(Us); + ei.attackedBy[Us][ALL_PIECES] = ei.attackedBy[Us][PAWN] = ei.pi->pawn_attacks(Us); // Init king safety tables only if we are going to use them if (pos.count(Us) && pos.non_pawn_material(Us) > QueenValueMg + PawnValueMg) @@ -422,10 +233,10 @@ Value do_evaluate(const Position& pos) { } - // evaluate_outposts() evaluates bishop and knight outpost squares + // evaluate_outpost() evaluates bishop and knight outpost squares template - Score evaluate_outposts(const Position& pos, EvalInfo& ei, Square s) { + Score evaluate_outpost(const Position& pos, const EvalInfo& ei, Square s) { const Color Them = (Us == WHITE ? BLACK : WHITE); @@ -445,19 +256,20 @@ Value do_evaluate(const Position& pos) { bonus += bonus / 2; } - return make_score(bonus, bonus); + return make_score(bonus * 2, bonus / 2); } // evaluate_pieces() assigns bonuses and penalties to the pieces of a given color template - Score evaluate_pieces(const Position& pos, EvalInfo& ei, Score* mobility, Bitboard mobilityArea) { + Score evaluate_pieces(const Position& pos, EvalInfo& ei, Score* mobility, Bitboard* mobilityArea) { 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 Square* pl = pos.list(Us); @@ -473,7 +285,7 @@ Value do_evaluate(const Position& pos) { if (ei.pinnedPieces[Us] & s) b &= LineBB[pos.king_square(Us)][s]; - ei.attackedBy[Us][Pt] |= b; + ei.attackedBy[Us][ALL_PIECES] |= ei.attackedBy[Us][Pt] |= b; if (b & ei.kingRing[Them]) { @@ -484,8 +296,13 @@ Value do_evaluate(const Position& pos) { ei.kingAdjacentZoneAttacksCount[Us] += popcount(bb); } - int mob = Pt != QUEEN ? popcount(b & mobilityArea) - : popcount(b & mobilityArea); + if (Pt == QUEEN) + b &= ~( ei.attackedBy[Them][KNIGHT] + | ei.attackedBy[Them][BISHOP] + | ei.attackedBy[Them][ROOK]); + + int mob = Pt != QUEEN ? popcount(b & mobilityArea[Us]) + : popcount(b & mobilityArea[Us]); mobility[Us] += MobilityBonus[Pt][mob]; @@ -500,13 +317,9 @@ Value do_evaluate(const Position& pos) { if (Pt == BISHOP) score -= BishopPawns * ei.pi->pawns_on_same_color_squares(Us, s); - // Penalty for knight when there are few enemy pawns - if (Pt == KNIGHT) - score -= KnightPawns * std::max(5 - pos.count(Them), 0); - - // Bishop and knight outposts squares + // Bishop and knight outpost square if (!(pos.pieces(Them, PAWN) & pawn_attack_span(Us, s))) - score += evaluate_outposts(pos, ei, s); + score += evaluate_outpost(pos, ei, s); // Bishop or knight behind a pawn if ( relative_rank(Us, s) < RANK_5 @@ -514,28 +327,21 @@ Value do_evaluate(const Position& pos) { score += MinorBehindPawn; } - if ( (Pt == ROOK || Pt == QUEEN) - && relative_rank(Us, s) >= RANK_5) - { - // Major piece on 7th rank and enemy king trapped on 8th - if ( relative_rank(Us, s) == RANK_7 - && relative_rank(Us, pos.king_square(Them)) == RANK_8) - score += Pt == ROOK ? RookOn7th : QueenOn7th; - - // Major piece attacking enemy pawns on the same rank/file - Bitboard pawns = pos.pieces(Them, PAWN) & PseudoAttacks[ROOK][s]; - if (pawns) - score += popcount(pawns) * (Pt == ROOK ? RookOnPawn : QueenOnPawn); - } - - // Special extra evaluation for rooks if (Pt == ROOK) { + // Rook piece attacking enemy pawns on the same rank/file + if (relative_rank(Us, s) >= RANK_5) + { + Bitboard pawns = pos.pieces(Them, PAWN) & PseudoAttacks[ROOK][s]; + if (pawns) + score += popcount(pawns) * RookOnPawn; + } + // Give a bonus for a rook on a open or semi-open file - if (ei.pi->semiopen(Us, file_of(s))) - score += ei.pi->semiopen(Them, file_of(s)) ? RookOpenFile : RookSemiopenFile; + if (ei.pi->semiopen_file(Us, file_of(s))) + score += ei.pi->semiopen_file(Them, file_of(s)) ? RookOpenFile : RookSemiOpenFile; - if (mob > 3 || ei.pi->semiopen(Us, file_of(s))) + if (mob > 3 || ei.pi->semiopen_file(Us, file_of(s))) continue; Square ksq = pos.king_square(Us); @@ -544,8 +350,8 @@ Value do_evaluate(const Position& pos) { // king has lost its castling capability. 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_on_side(Us, file_of(ksq), file_of(ksq) < FILE_E)) - score -= (TrappedRook - make_score(mob * 8, 0)) * (pos.can_castle(Us) ? 1 : 2); + && !ei.pi->semiopen_side(Us, file_of(ksq), file_of(s) < file_of(ksq))) + score -= (TrappedRook - make_score(mob * 22, 0)) * (1 + !pos.can_castle(Us)); } // An important Chess960 pattern: A cornered bishop blocked by a friendly @@ -566,35 +372,13 @@ Value do_evaluate(const Position& pos) { if (Trace) Tracing::terms[Us][Pt] = score; - return score; + return score - evaluate_pieces(pos, ei, mobility, mobilityArea); } - - // evaluate_pieces() assigns bonuses and penalties to all the - // pieces of a given color. - - template - Score evaluate_pieces(const Position& pos, EvalInfo& ei, Score* mobility) { - - const Color Them = (Us == WHITE ? BLACK : WHITE); - - // Do not include in mobility squares protected by enemy pawns or occupied by our pieces - const Bitboard mobilityArea = ~(ei.attackedBy[Them][PAWN] | pos.pieces(Us, PAWN, KING)); - - Score score = evaluate_pieces(pos, ei, mobility, mobilityArea) - + evaluate_pieces(pos, ei, mobility, mobilityArea) - + evaluate_pieces(pos, ei, mobility, mobilityArea) - + evaluate_pieces(pos, ei, mobility, mobilityArea); - - // Sum up all attacked squares (updated in evaluate_pieces) - ei.attackedBy[Us][ALL_PIECES] = ei.attackedBy[Us][PAWN] | ei.attackedBy[Us][KNIGHT] - | ei.attackedBy[Us][BISHOP] | ei.attackedBy[Us][ROOK] - | ei.attackedBy[Us][QUEEN] | ei.attackedBy[Us][KING]; - if (Trace) - Tracing::terms[Us][Tracing::MOBILITY] = apply_weight(mobility[Us], Weights[Mobility]); - - return score; - } + template<> + Score evaluate_pieces(const Position&, EvalInfo&, Score*, Bitboard*) { return SCORE_ZERO; } + template<> + Score evaluate_pieces(const Position&, EvalInfo&, Score*, Bitboard*) { return SCORE_ZERO; } // evaluate_king() assigns bonuses and penalties to a king of a given color @@ -629,6 +413,7 @@ Value do_evaluate(const Position& pos) { // the pawn shelter (current 'score' value). attackUnits = std::min(20, (ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them]) / 2) + 3 * (ei.kingAdjacentZoneAttacksCount[Them] + popcount(undefended)) + + 2 * (ei.pinnedPieces[Us] != 0) - mg_value(score) / 32; // Analyse the enemy's safe queen contact checks. Firstly, find the @@ -642,9 +427,7 @@ Value do_evaluate(const Position& pos) { | ei.attackedBy[Them][BISHOP] | ei.attackedBy[Them][ROOK]); if (b) - attackUnits += QueenContactCheck - * popcount(b) - * (Them == pos.side_to_move() ? 2 : 1); + attackUnits += QueenContactCheck * popcount(b); } // Analyse the enemy's safe rook contact checks. Firstly, find the @@ -662,9 +445,7 @@ Value do_evaluate(const Position& pos) { | ei.attackedBy[Them][BISHOP] | ei.attackedBy[Them][QUEEN]); if (b) - attackUnits += RookContactCheck - * popcount(b) - * (Them == pos.side_to_move() ? 2 : 1); + attackUnits += RookContactCheck * popcount(b); } // Analyse the enemy's safe distance checks for sliders and knights @@ -698,7 +479,7 @@ Value do_evaluate(const Position& pos) { // Finally, extract the king danger score from the KingDanger[] // array and subtract the score from evaluation. - score -= KingDanger[Us == Search::RootColor][attackUnits]; + score -= KingDanger[attackUnits]; } if (Trace) @@ -716,17 +497,19 @@ Value do_evaluate(const Position& pos) { const Color Them = (Us == WHITE ? BLACK : WHITE); - Bitboard b, undefendedMinors, weakEnemies; + Bitboard b, weakEnemies, protectedEnemies; Score score = SCORE_ZERO; + enum { Minor, Major }; - // Undefended minors get penalized even if they are not under attack - undefendedMinors = pos.pieces(Them, BISHOP, KNIGHT) - & ~ei.attackedBy[Them][ALL_PIECES]; + // Protected enemies + protectedEnemies = (pos.pieces(Them) ^ pos.pieces(Them,PAWN)) + & ei.attackedBy[Them][PAWN] + & (ei.attackedBy[Us][KNIGHT] | ei.attackedBy[Us][BISHOP]); - if (undefendedMinors) - score += UndefendedMinor; + if(protectedEnemies) + score += Threat[Minor][type_of(pos.piece_on(lsb(protectedEnemies)))]; - // Enemy pieces not defended by a pawn and under our attack + // Enemies not defended by a pawn and under our attack weakEnemies = pos.pieces(Them) & ~ei.attackedBy[Them][PAWN] & ei.attackedBy[Us][ALL_PIECES]; @@ -736,11 +519,19 @@ Value do_evaluate(const Position& pos) { { b = weakEnemies & (ei.attackedBy[Us][KNIGHT] | ei.attackedBy[Us][BISHOP]); if (b) - score += Threat[0][type_of(pos.piece_on(lsb(b)))]; + score += Threat[Minor][type_of(pos.piece_on(lsb(b)))]; b = weakEnemies & (ei.attackedBy[Us][ROOK] | ei.attackedBy[Us][QUEEN]); if (b) - score += Threat[1][type_of(pos.piece_on(lsb(b)))]; + score += Threat[Major][type_of(pos.piece_on(lsb(b)))]; + + b = weakEnemies & ~ei.attackedBy[Them][ALL_PIECES]; + if (b) + score += more_than_one(b) ? Hanging * popcount(b) : Hanging; + + b = weakEnemies & pos.pieces(Them, PAWN) & ei.attackedBy[Us][KING]; + if (b) + score += more_than_one(b) ? KingOnPawnMany : KingOnPawnOne; } if (Trace) @@ -757,7 +548,7 @@ Value do_evaluate(const Position& pos) { const Color Them = (Us == WHITE ? BLACK : WHITE); - Bitboard b, squaresToQueen, defendedSquares, unsafeSquares, supportingPawns; + Bitboard b, squaresToQueen, defendedSquares, unsafeSquares; Score score = SCORE_ZERO; b = ei.pi->passed_pawns(Us); @@ -768,87 +559,58 @@ Value do_evaluate(const Position& pos) { assert(pos.pawn_passed(Us, s)); - int r = int(relative_rank(Us, s) - RANK_2); + int r = relative_rank(Us, s) - RANK_2; int rr = r * (r - 1); // Base bonus based on rank - Value mbonus = Value(17 * rr); - Value ebonus = Value(7 * (rr + r + 1)); + Value mbonus = Value(17 * rr), ebonus = Value(7 * (rr + r + 1)); if (rr) { Square blockSq = s + pawn_push(Us); // Adjust bonus based on the king's proximity - ebonus += Value(square_distance(pos.king_square(Them), blockSq) * 5 * rr) - - Value(square_distance(pos.king_square(Us ), blockSq) * 2 * rr); + ebonus += square_distance(pos.king_square(Them), blockSq) * 5 * rr + - square_distance(pos.king_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) - ebonus -= Value(rr * square_distance(pos.king_square(Us), blockSq + pawn_push(Us))); + ebonus -= square_distance(pos.king_square(Us), blockSq + pawn_push(Us)) * rr; // If the pawn is free to advance, then increase the bonus if (pos.empty(blockSq)) { - squaresToQueen = forward_bb(Us, s); - - // If there is an enemy rook or queen attacking the pawn from behind, - // add all X-ray attacks by the rook or queen. Otherwise consider only - // the squares in the pawn's path attacked or occupied by the enemy. - if ( unlikely(forward_bb(Them, s) & pos.pieces(Them, ROOK, QUEEN)) - && (forward_bb(Them, s) & pos.pieces(Them, ROOK, QUEEN) & pos.attacks_from(s))) - unsafeSquares = squaresToQueen; - else - unsafeSquares = squaresToQueen & (ei.attackedBy[Them][ALL_PIECES] | pos.pieces(Them)); - - if ( unlikely(forward_bb(Them, s) & pos.pieces(Us, ROOK, QUEEN)) - && (forward_bb(Them, s) & pos.pieces(Us, ROOK, QUEEN) & pos.attacks_from(s))) - defendedSquares = squaresToQueen; - else - defendedSquares = squaresToQueen & ei.attackedBy[Us][ALL_PIECES]; - - // If there aren't any enemy attacks, then assign a huge bonus. - // The bonus will be a bit smaller if at least the block square - // isn't attacked, otherwise assign the smallest possible bonus. - int k = !unsafeSquares ? 15 : !(unsafeSquares & blockSq) ? 9 : 3; - - // Assign a big bonus if the path to the queen is fully defended, - // otherwise assign a bit less of a bonus if at least the block - // square is defended. + // 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); + + Bitboard bb = forward_bb(Them, s) & pos.pieces(ROOK, QUEEN) & pos.attacks_from(s); + + if (!(pos.pieces(Us) & bb)) + defendedSquares &= ei.attackedBy[Us][ALL_PIECES]; + + if (!(pos.pieces(Them) & bb)) + unsafeSquares &= ei.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 ? 15 : !(unsafeSquares & blockSq) ? 9 : 0; + + // If the path to queen is fully defended, assign a big bonus. + // Otherwise assign a smaller bonus if the block square is defended. if (defendedSquares == squaresToQueen) k += 6; else if (defendedSquares & blockSq) - k += (unsafeSquares & defendedSquares) == unsafeSquares ? 4 : 2; + k += 4; - mbonus += Value(k * rr), ebonus += Value(k * rr); + mbonus += k * rr, ebonus += k * rr; } + else if(pos.pieces(Us) & blockSq) + mbonus += rr * 3 + r * 2 + 3, ebonus += rr + r * 2; } // rr != 0 - // Increase the bonus if the passed pawn is supported by a friendly pawn - // on the same rank and a bit smaller if it's on the previous rank. - supportingPawns = pos.pieces(Us, PAWN) & adjacent_files_bb(file_of(s)); - if (supportingPawns & rank_bb(s)) - ebonus += Value(r * 20); - - else if (supportingPawns & rank_bb(s - pawn_push(Us))) - ebonus += Value(r * 12); - - // Rook pawns are a special case: They are sometimes worse, and - // sometimes better than other passed pawns. It is difficult to find - // good rules for determining whether they are good or bad. For now, - // we try the following: Increase the value for rook pawns if the - // other side has no pieces apart from a knight, and decrease the - // value if the other side has a rook or queen. - if (file_of(s) == FILE_A || file_of(s) == FILE_H) - { - if (pos.non_pawn_material(Them) <= KnightValueMg) - ebonus += ebonus / 4; - - else if (pos.pieces(Them, ROOK, QUEEN)) - ebonus -= ebonus / 4; - } - if (pos.count(Us) < pos.count(Them)) ebonus += ebonus / 4; @@ -864,17 +626,14 @@ Value do_evaluate(const Position& pos) { // evaluate_unstoppable_pawns() scores the most advanced among the passed and - // candidate pawns. In case opponent has no pieces but pawns, this is somewhat - // related to the possibility that pawns are unstoppable. + // candidate pawns. In case both players have no pieces but pawns, this is + // somewhat related to the possibility that pawns are unstoppable. - Score evaluate_unstoppable_pawns(const Position& pos, Color us, const EvalInfo& ei) { + Score evaluate_unstoppable_pawns(Color us, const EvalInfo& ei) { Bitboard b = ei.pi->passed_pawns(us) | ei.pi->candidate_pawns(us); - if (!b || pos.non_pawn_material(~us)) - return SCORE_ZERO; - - return Unstoppable * int(relative_rank(us, frontmost_sq(us, b))); + return b ? Unstoppable * int(relative_rank(us, frontmost_sq(us, b))) : SCORE_ZERO; } @@ -910,42 +669,136 @@ Value do_evaluate(const Position& pos) { } - // interpolate() interpolates between a middlegame and an endgame score, - // based on game phase. It also scales the return value by a ScaleFactor array. + // do_evaluate() is the evaluation entry point, called directly from evaluate() - Value interpolate(const Score& v, Phase ph, ScaleFactor sf) { + template + Value do_evaluate(const Position& pos) { - assert(-VALUE_INFINITE < mg_value(v) && mg_value(v) < VALUE_INFINITE); - assert(-VALUE_INFINITE < eg_value(v) && eg_value(v) < VALUE_INFINITE); - assert(PHASE_ENDGAME <= ph && ph <= PHASE_MIDGAME); + assert(!pos.checkers()); - int eg = (eg_value(v) * int(sf)) / SCALE_FACTOR_NORMAL; - return Value((mg_value(v) * int(ph) + eg * int(PHASE_MIDGAME - ph)) / PHASE_MIDGAME); - } + EvalInfo ei; + Score score, mobility[2] = { SCORE_ZERO, SCORE_ZERO }; + Thread* thisThread = pos.this_thread(); + + // 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 + ei.mi = Material::probe(pos, thisThread->materialTable, thisThread->endgames); + score += ei.mi->material_value(); + + // If we have a specialized evaluation function for the current material + // configuration, call it and return. + if (ei.mi->specialized_eval_exists()) + return ei.mi->evaluate(pos); + + // Probe the pawn hash table + ei.pi = Pawns::probe(pos, thisThread->pawnsTable); + score += apply_weight(ei.pi->pawns_value(), Weights[PawnStructure]); + + // Initialize attack and king safety bitboards + init_eval_info(pos, ei); + init_eval_info(pos, ei); + + ei.attackedBy[WHITE][ALL_PIECES] |= ei.attackedBy[WHITE][KING]; + ei.attackedBy[BLACK][ALL_PIECES] |= ei.attackedBy[BLACK][KING]; + + // Do not include in mobility squares protected by enemy pawns or occupied by our pawns or king + Bitboard mobilityArea[] = { ~(ei.attackedBy[BLACK][PAWN] | pos.pieces(WHITE, PAWN, KING)), + ~(ei.attackedBy[WHITE][PAWN] | pos.pieces(BLACK, PAWN, KING)) }; + + // Evaluate pieces and mobility + score += evaluate_pieces(pos, ei, mobility, mobilityArea); + score += apply_weight(mobility[WHITE] - mobility[BLACK], Weights[Mobility]); + + // Evaluate kings after all other pieces because we need complete attack + // information when computing the king safety evaluation. + score += evaluate_king(pos, ei) + - evaluate_king(pos, ei); + + // Evaluate tactical threats, we need full attack information including king + score += evaluate_threats(pos, ei) + - 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)) + score += evaluate_unstoppable_pawns(WHITE, ei) + - evaluate_unstoppable_pawns(BLACK, ei); + + // Evaluate space for both sides, only in middlegame + if (ei.mi->space_weight()) + { + int s = evaluate_space(pos, ei) - evaluate_space(pos, ei); + score += apply_weight(s * ei.mi->space_weight(), Weights[Space]); + } - // apply_weight() weights score v by score w trying to prevent overflow - Score apply_weight(Score v, Score w) { + // Scale winning side if position is more drawish than it appears + Color strongSide = eg_value(score) > VALUE_DRAW ? WHITE : BLACK; + ScaleFactor sf = ei.mi->scale_factor(pos, strongSide); - return make_score((int(mg_value(v)) * mg_value(w)) / 0x100, - (int(eg_value(v)) * eg_value(w)) / 0x100); - } + // 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.mi->game_phase() < PHASE_MIDGAME + && (sf == SCALE_FACTOR_NORMAL || sf == SCALE_FACTOR_ONEPAWN)) + { + if (pos.opposite_bishops()) { + // Ignoring any pawns, do both sides only have a single bishop and no + // other pieces? + if ( pos.non_pawn_material(WHITE) == BishopValueMg + && pos.non_pawn_material(BLACK) == BishopValueMg) + { + // Check for KBP vs KB with only a single pawn that is almost + // certainly a draw or at least two pawns. + bool one_pawn = (pos.count(WHITE) + pos.count(BLACK) == 1); + sf = one_pawn ? ScaleFactor(8) : ScaleFactor(32); + } + else + // Endgame with opposite-colored bishops, but also other pieces. Still + // a bit drawish, but not as drawish as with only the two bishops. + sf = ScaleFactor(50 * sf / SCALE_FACTOR_NORMAL); + } else if ( abs(eg_value(score)) <= BishopValueEg + && ei.pi->pawn_span(strongSide) <= 1 + && !pos.pawn_passed(~strongSide, pos.king_square(~strongSide))) { + // Endings where weaker side can be place his king in front of the opponent's pawns are drawish. + sf = ScaleFactor(ScalePawnSpan[ei.pi->pawn_span(strongSide)]); + } + } - // weight_option() computes the value of an evaluation weight, by combining - // two UCI-configurable weights (midgame and endgame) with an internal weight. + // Interpolate between a middlegame and a (scaled by 'sf') endgame score + Value v = mg_value(score) * int(ei.mi->game_phase()) + + eg_value(score) * int(PHASE_MIDGAME - ei.mi->game_phase()) * sf / SCALE_FACTOR_NORMAL; - Score weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight) { + v /= int(PHASE_MIDGAME); - // Scale option value from 100 to 256 - int mg = Options[mgOpt] * 256 / 100; - int eg = Options[egOpt] * 256 / 100; + // In case of tracing add all single evaluation contributions for both white and black + if (Trace) + { + Tracing::add_term(Tracing::MATERIAL, pos.psq_score()); + Tracing::add_term(Tracing::IMBALANCE, ei.mi->material_value()); + Tracing::add_term(PAWN, ei.pi->pawns_value()); + Tracing::add_term(Tracing::MOBILITY, apply_weight(mobility[WHITE], Weights[Mobility]) + , apply_weight(mobility[BLACK], Weights[Mobility])); + Score w = ei.mi->space_weight() * evaluate_space(pos, ei); + Score b = ei.mi->space_weight() * evaluate_space(pos, ei); + Tracing::add_term(Tracing::SPACE, apply_weight(w, Weights[Space]), apply_weight(b, Weights[Space])); + Tracing::add_term(Tracing::TOTAL, score); + Tracing::ei = ei; + Tracing::sf = sf; + } - return apply_weight(make_score(mg, eg), internalWeight); + return pos.side_to_move() == WHITE ? v : -v; } // Tracing function definitions - double Tracing::to_cp(Value v) { return double(v) / PawnValueMg; } + double Tracing::to_cp(Value v) { return double(v) / PawnValueEg; } void Tracing::add_term(int idx, Score wScore, Score bScore) { @@ -959,20 +812,19 @@ Value do_evaluate(const Position& pos) { Score bScore = terms[BLACK][idx]; switch (idx) { - case PST: case IMBALANCE: case PAWN: case TOTAL: - ss << std::setw(20) << name << " | --- --- | --- --- | " - << std::setw(6) << to_cp(mg_value(wScore)) << " " - << std::setw(6) << to_cp(eg_value(wScore)) << " \n"; + case MATERIAL: case IMBALANCE: case PAWN: case TOTAL: + ss << std::setw(15) << name << " | --- --- | --- --- | " + << std::setw(5) << to_cp(mg_value(wScore - bScore)) << " " + << std::setw(5) << to_cp(eg_value(wScore - bScore)) << " \n"; break; default: - ss << std::setw(20) << name << " | " << std::noshowpos + ss << std::setw(15) << name << " | " << std::noshowpos << std::setw(5) << to_cp(mg_value(wScore)) << " " << std::setw(5) << to_cp(eg_value(wScore)) << " | " << std::setw(5) << to_cp(mg_value(bScore)) << " " << std::setw(5) << to_cp(eg_value(bScore)) << " | " - << std::showpos - << std::setw(6) << to_cp(mg_value(wScore - bScore)) << " " - << std::setw(6) << to_cp(eg_value(wScore - bScore)) << " \n"; + << std::setw(5) << to_cp(mg_value(wScore - bScore)) << " " + << std::setw(5) << to_cp(eg_value(wScore - bScore)) << " \n"; } } @@ -981,15 +833,16 @@ Value do_evaluate(const Position& pos) { std::memset(terms, 0, sizeof(terms)); Value v = do_evaluate(pos); + v = pos.side_to_move() == WHITE ? v : -v; // White's point of view std::stringstream ss; - ss << std::showpoint << std::showpos << std::fixed << std::setprecision(2) - << " Eval term | White | Black | Total \n" - << " | MG EG | MG EG | MG EG \n" - << "---------------------+-------------+-------------+---------------\n"; + ss << std::showpoint << std::noshowpos << std::fixed << std::setprecision(2) + << " Eval term | White | Black | Total \n" + << " | MG EG | MG EG | MG EG \n" + << "----------------+-------------+-------------+-------------\n"; - format_row(ss, "Material, PST, Tempo", PST); - format_row(ss, "Material imbalance", IMBALANCE); + format_row(ss, "Material", MATERIAL); + format_row(ss, "Imbalance", IMBALANCE); format_row(ss, "Pawns", PAWN); format_row(ss, "Knights", KNIGHT); format_row(ss, "Bishops", BISHOP); @@ -1001,15 +854,49 @@ Value do_evaluate(const Position& pos) { format_row(ss, "Passed pawns", PASSED); format_row(ss, "Space", SPACE); - ss << "---------------------+-------------+-------------+---------------\n"; + ss << "----------------+-------------+-------------+-------------\n"; format_row(ss, "Total", TOTAL); - ss << "\nScaling: " << std::noshowpos - << std::setw(6) << 100.0 * ei.mi->game_phase() / 128.0 << "% MG, " - << std::setw(6) << 100.0 * (1.0 - ei.mi->game_phase() / 128.0) << "% * " - << std::setw(6) << (100.0 * sf) / SCALE_FACTOR_NORMAL << "% EG.\n" - << "Total evaluation: " << to_cp(v); + ss << "\nTotal Evaluation: " << to_cp(v) << " (white side)\n"; return ss.str(); } -} + +} // namespace + + +namespace Eval { + + /// 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. + + Value evaluate(const Position& pos) { + return do_evaluate(pos) + Tempo; + } + + + /// trace() is like evaluate(), but instead of returning a value, it returns + /// a string (suitable for outputting to stdout) that contains the detailed + /// descriptions and values of each evaluation term. It's mainly used for + /// debugging. + std::string trace(const Position& pos) { + return Tracing::do_trace(pos); + } + + + /// init() computes evaluation weights from the corresponding UCI parameters + /// and setup king tables. + + void init() { + + const double MaxSlope = 30; + const double Peak = 1280; + + for (int t = 0, i = 1; i < 100; ++i) + { + t = int(std::min(Peak, std::min(0.4 * i * i, t + MaxSlope))); + KingDanger[i] = apply_weight(make_score(t, 0), Weights[KingSafety]); + } + } + +} // namespace Eval