X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fevaluate.cpp;h=c880b7c7845f3c881ba2d7600a662c393e6a9436;hp=57bbfe09d87f6d97a4a940a3be85930d0f9641fb;hb=9369f4963d9376820cb5ca4bad66b86e67b0a010;hpb=553ead429d94b6314ff14aa3eb724f47987e5a52 diff --git a/src/evaluate.cpp b/src/evaluate.cpp index 57bbfe09..c880b7c7 100644 --- a/src/evaluate.cpp +++ b/src/evaluate.cpp @@ -1,7 +1,7 @@ /* Stockfish, a UCI chess playing engine derived from Glaurung 2.1 Copyright (C) 2004-2008 Tord Romstad (Glaurung author) - Copyright (C) 2008-2014 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, 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 @@ -17,17 +17,16 @@ along with this program. If not, see . */ +#include #include +#include // For std::memset #include #include -#include #include "bitcount.h" #include "evaluate.h" #include "material.h" #include "pawns.h" -#include "thread.h" -#include "ucioption.h" namespace { @@ -58,16 +57,15 @@ namespace { // kingAttackersWeight[color] is the sum of the "weight" of the pieces of the // given color which attack a square in the kingRing of the enemy king. The - // weights of the individual piece types are given by the variables - // QueenAttackWeight, RookAttackWeight, BishopAttackWeight and - // KnightAttackWeight in evaluate.cpp + // weights of the individual piece types are given by the elements in the + // KingAttackWeights array. int kingAttackersWeight[COLOR_NB]; - // kingAdjacentZoneAttacksCount[color] is the number of attacks to squares - // directly adjacent to the king of the given color. Pieces which attack - // more than one square are counted multiple times. For instance, if black's - // king is on g8 and there's a white knight on g5, this knight adds - // 2 to kingAdjacentZoneAttacksCount[BLACK]. + // kingAdjacentZoneAttacksCount[color] is the number of attacks by the given + // color to squares directly adjacent to the enemy king. Pieces which attack + // more than one square are counted multiple times. For instance, if there is + // 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]; @@ -76,51 +74,44 @@ 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]; + Score scores[COLOR_NB][TERMS_NB]; EvalInfo ei; ScaleFactor sf; double to_cp(Value v); - void add_term(int idx, Score term_w, Score term_b = SCORE_ZERO); - void format_row(std::stringstream& ss, const char* name, int idx); + void write(int idx, Color c, Score s); + void write(int idx, Score w, Score b = SCORE_ZERO); + void print(std::stringstream& ss, const char* name, int idx); 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}, {322, 0} + }; - typedef Value V; + #define V(v) 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) } @@ -145,39 +136,42 @@ namespace { V(0), V(5), V(8), V(8), V(8), V(8), V(5), V(0) } }; - // Threat[attacking][attacked] contains bonuses according to which piece - // type attacks which one. - const Score Threat[][PIECE_TYPE_NB] = { - { S(0, 0), S( 7, 39), S(24, 49), S(24, 49), S(41,100), S(41,100) }, // Minor - { S(0, 0), S(15, 39), S(15, 45), S(15, 45), S(15, 45), S(24, 49) } // Major + // Threat[defended/weak][minor/major attacking][attacked PieceType] contains + // bonuses according to which piece type attacks which one. + const Score Threat[][2][PIECE_TYPE_NB] = { + { { S(0, 0), S( 0, 0), S(19, 37), S(24, 37), S(44, 97), S(35,106) }, // Defended Minor + { S(0, 0), S( 0, 0), S( 9, 14), S( 9, 14), S( 7, 14), S(24, 48) } }, // Defended Major + { { S(0, 0), S( 0,32), S(33, 41), S(31, 50), S(41,100), S(35,104) }, // Weak Minor + { S(0, 0), S( 0,27), S(26, 57), S(26, 57), S(0 , 43), S(23, 51) } } // Weak Major }; // 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(107, 138), S(84, 122), S(114, 203), S(121, 217) }; - #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 KingOnOne = S( 2, 58); + const Score KingOnMany = S( 6,125); + const Score RookOnPawn = S( 7, 27); + const Score RookOnOpenFile = S(43, 21); + const Score RookOnSemiOpenFile = S(19, 10); + const Score BishopPawns = S( 8, 12); + const Score MinorBehindPawn = S(16, 0); + const Score TrappedRook = S(92, 0); + const Score Unstoppable = S( 0, 20); + const Score Hanging = S(31, 26); + const Score PawnAttackThreat = S(20, 20); + const Score PawnSafePush = S( 5, 5); // 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 + #undef V // SpaceMask[Color] contains the area of the board which is considered // by the space evaluation. In the middlegame, each side is given a bonus @@ -188,213 +182,32 @@ namespace { (FileCBB | FileDBB | FileEBB | FileFBB) & (Rank7BB | Rank6BB | Rank5BB) }; - // King danger constants and variables. The king danger scores are taken - // from KingDanger[]. Various little "meta-bonuses" measuring the strength + // 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[]. // // KingAttackWeights[PieceType] contains king attack weights by piece type - const int KingAttackWeights[] = { 0, 0, 2, 2, 3, 5 }; + const int KingAttackWeights[] = { 0, 0, 7, 5, 4, 1 }; // Bonuses for enemy's safe checks - const int QueenContactCheck = 24; - const int RookContactCheck = 16; - const int QueenCheck = 12; - const int RookCheck = 8; - 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); + const int QueenContactCheck = 89; + const int RookContactCheck = 71; + const int QueenCheck = 50; + const int RookCheck = 37; + const int BishopCheck = 6; + const int KnightCheck = 14; + + // KingDanger[attackUnits] contains the actual king danger weighted + // scores, indexed by a calculated integer number. + Score KingDanger[512]; + + // apply_weight() weighs score 's' by weight 'w' trying to prevent overflow + Score apply_weight(Score s, const Weight& w) { + return make_score(mg_value(s) * w.mg / 256, eg_value(s) * w.eg / 256); } - /// 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); - } - - Value v = interpolate(score, ei.mi->game_phase(), sf); - - // 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; - } - - 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. @@ -407,10 +220,10 @@ 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) + if (pos.non_pawn_material(Us) >= QueenValueMg) { ei.kingRing[Them] = b | shift_bb(b); b &= ei.attackedBy[Us][PAWN]; @@ -422,10 +235,10 @@ 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 +258,20 @@ 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 +287,7 @@ 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 +298,13 @@ 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]; @@ -496,105 +315,72 @@ Value do_evaluate(const Position& pos) { if (Pt == BISHOP || Pt == KNIGHT) { - // Penalty for bishop with same colored pawns - 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 + // Bonus for 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 + // Bonus when behind a pawn if ( relative_rank(Us, s) < RANK_5 && (pos.pieces(PAWN) & (s + pawn_push(Us)))) 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); + // Penalty for pawns on same color square of bishop + if (Pt == BISHOP) + score -= BishopPawns * ei.pi->pawns_on_same_color_squares(Us, s); + + // An important Chess960 pattern: A cornered bishop blocked by a friendly + // pawn diagonally in front of it is a very serious problem, especially + // when that pawn is also blocked. + if ( Pt == BISHOP + && 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); + 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 + : TrappedBishopA1H1; + } } - // Special extra evaluation for rooks if (Pt == ROOK) { - // 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 (mob > 3 || ei.pi->semiopen(Us, file_of(s))) - continue; + // Bonus for aligning with enemy pawns on the same rank/file + if (relative_rank(Us, s) >= RANK_5) + { + Bitboard alignedPawns = pos.pieces(Them, PAWN) & PseudoAttacks[ROOK][s]; + if (alignedPawns) + score += popcount(alignedPawns) * RookOnPawn; + } - Square ksq = pos.king_square(Us); + // Bonus when on an open or semi-open file + if (ei.pi->semiopen_file(Us, file_of(s))) + score += ei.pi->semiopen_file(Them, file_of(s)) ? RookOnOpenFile : RookOnSemiOpenFile; - // Penalize rooks which are trapped by a king. Penalize more if the - // 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); - } + // Penalize when trapped by the king, even more if king cannot castle + if (mob <= 3 && !ei.pi->semiopen_file(Us, file_of(s))) + { + Square ksq = pos.king_square(Us); - // An important Chess960 pattern: A cornered bishop blocked by a friendly - // pawn diagonally in front of it is a very serious problem, especially - // when that pawn is also blocked. - if ( Pt == BISHOP - && 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); - 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 - : TrappedBishopA1H1; + 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))) + score -= (TrappedRook - make_score(mob * 22, 0)) * (1 + !pos.can_castle(Us)); + } } } if (Trace) - Tracing::terms[Us][Pt] = score; + Tracing::write(Pt, Us, score); - return score; + // Recursively call evaluate_pieces() of next piece type until KING excluded + 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 @@ -623,33 +409,32 @@ Value do_evaluate(const Position& pos) { | ei.attackedBy[Us][QUEEN]); // Initialize the 'attackUnits' variable, which is used later on as an - // index to the KingDanger[] array. The initial value is based on the + // 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(20, (ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them]) / 2) - + 3 * (ei.kingAdjacentZoneAttacksCount[Them] + popcount(undefended)) - - mg_value(score) / 32; + attackUnits = std::min(74, ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them]) + + 8 * ei.kingAdjacentZoneAttacksCount[Them] + + 25 * popcount(undefended) + + 11 * (ei.pinnedPieces[Us] != 0) + - mg_value(score) / 8 + - !pos.count(Them) * 60; // Analyse the enemy's safe queen contact checks. Firstly, find the - // undefended squares around the king that are attacked by the enemy's - // queen... + // undefended squares around the king reachable by the enemy queen... b = undefended & ei.attackedBy[Them][QUEEN] & ~pos.pieces(Them); if (b) { // ...and then remove squares not supported by another enemy piece - b &= ( ei.attackedBy[Them][PAWN] | ei.attackedBy[Them][KNIGHT] - | ei.attackedBy[Them][BISHOP] | ei.attackedBy[Them][ROOK]); + b &= ei.attackedBy[Them][PAWN] | ei.attackedBy[Them][KNIGHT] + | 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 - // undefended squares around the king that are attacked by the enemy's - // rooks... + // undefended squares around the king reachable by the enemy rooks... b = undefended & ei.attackedBy[Them][ROOK] & ~pos.pieces(Them); // Consider only squares where the enemy's rook gives check @@ -662,15 +447,13 @@ 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 - safe = ~(pos.pieces(Them) | ei.attackedBy[Us][ALL_PIECES]); + safe = ~(ei.attackedBy[Us][ALL_PIECES] | pos.pieces(Them)); - b1 = pos.attacks_from(ksq) & safe; + b1 = pos.attacks_from(ksq) & safe; b2 = pos.attacks_from(ksq) & safe; // Enemy queen safe checks @@ -693,16 +476,13 @@ Value do_evaluate(const Position& pos) { if (b) attackUnits += KnightCheck * popcount(b); - // To index KingDanger[] attackUnits must be in [0, 99] range - attackUnits = std::min(99, std::max(0, attackUnits)); - // Finally, extract the king danger score from the KingDanger[] // array and subtract the score from evaluation. - score -= KingDanger[Us == Search::RootColor][attackUnits]; + score -= KingDanger[std::max(std::min(attackUnits, 399), 0)]; } if (Trace) - Tracing::terms[Us][KING] = score; + Tracing::write(KING, Us, score); return score; } @@ -714,37 +494,81 @@ Value do_evaluate(const Position& pos) { template Score evaluate_threats(const Position& pos, const EvalInfo& ei) { - const Color Them = (Us == WHITE ? BLACK : WHITE); + const Color Them = (Us == WHITE ? BLACK : WHITE); + const Square Up = (Us == WHITE ? 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); - Bitboard b, undefendedMinors, weakEnemies; + enum { Defended, Weak }; + enum { Minor, Major }; + + Bitboard b, weak, defended; Score score = SCORE_ZERO; - // Undefended minors get penalized even if they are not under attack - undefendedMinors = pos.pieces(Them, BISHOP, KNIGHT) - & ~ei.attackedBy[Them][ALL_PIECES]; + // Non-pawn enemies defended by a pawn + defended = (pos.pieces(Them) ^ pos.pieces(Them, PAWN)) + & ei.attackedBy[Them][PAWN]; - if (undefendedMinors) - score += UndefendedMinor; + // Add a bonus according to the kind of attacking pieces + if (defended) + { + b = defended & (ei.attackedBy[Us][KNIGHT] | ei.attackedBy[Us][BISHOP]); + while (b) + score += Threat[Defended][Minor][type_of(pos.piece_on(pop_lsb(&b)))]; - // Enemy pieces not defended by a pawn and under our attack - weakEnemies = pos.pieces(Them) - & ~ei.attackedBy[Them][PAWN] - & ei.attackedBy[Us][ALL_PIECES]; + b = defended & (ei.attackedBy[Us][ROOK]); + while (b) + score += Threat[Defended][Major][type_of(pos.piece_on(pop_lsb(&b)))]; + } + + // Enemies not defended by a pawn and under our attack + weak = pos.pieces(Them) + & ~ei.attackedBy[Them][PAWN] + & ei.attackedBy[Us][ALL_PIECES]; - // Add a bonus according if the attacking pieces are minor or major - if (weakEnemies) + // Add a bonus according to the kind of attacking pieces + if (weak) { - b = weakEnemies & (ei.attackedBy[Us][KNIGHT] | ei.attackedBy[Us][BISHOP]); + b = weak & (ei.attackedBy[Us][KNIGHT] | ei.attackedBy[Us][BISHOP]); + while (b) + score += Threat[Weak][Minor][type_of(pos.piece_on(pop_lsb(&b)))]; + + b = weak & (ei.attackedBy[Us][ROOK] | ei.attackedBy[Us][QUEEN]); + while (b) + score += Threat[Weak][Major][type_of(pos.piece_on(pop_lsb(&b)))]; + + b = weak & ~ei.attackedBy[Them][ALL_PIECES]; if (b) - score += Threat[0][type_of(pos.piece_on(lsb(b)))]; + score += Hanging * popcount(b); - b = weakEnemies & (ei.attackedBy[Us][ROOK] | ei.attackedBy[Us][QUEEN]); + b = weak & ei.attackedBy[Us][KING]; if (b) - score += Threat[1][type_of(pos.piece_on(lsb(b)))]; + score += more_than_one(b) ? KingOnMany : KingOnOne; } + // Add a small bonus for safe pawn pushes + b = pos.pieces(Us, PAWN) & ~TRank7BB; + b = shift_bb(b | (shift_bb(b & TRank2BB) & ~pos.pieces())); + + b &= ~pos.pieces() + & ~ei.attackedBy[Them][PAWN] + & (ei.attackedBy[Us][ALL_PIECES] | ~ei.attackedBy[Them][ALL_PIECES]); + + if (b) + score += popcount(b) * PawnSafePush; + + // Add another bonus if the pawn push attacks an enemy piece + b = (shift_bb(b) | shift_bb(b)) + & pos.pieces(Them) + & ~ei.attackedBy[Us][PAWN]; + + if (b) + score += popcount(b) * PawnAttackThreat; + if (Trace) - Tracing::terms[Us][Tracing::THREAT] = score; + Tracing::write(Tracing::THREAT, Us, score); return score; } @@ -757,7 +581,7 @@ 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 +592,58 @@ 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 += distance(pos.king_square(Them), blockSq) * 5 * rr + - 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 -= 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; @@ -856,36 +651,21 @@ Value do_evaluate(const Position& pos) { } if (Trace) - Tracing::terms[Us][Tracing::PASSED] = apply_weight(score, Weights[PassedPawns]); + Tracing::write(Tracing::PASSED, Us, apply_weight(score, Weights[PassedPawns])); // Add the scores to the middlegame and endgame eval return apply_weight(score, Weights[PassedPawns]); } - // 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. - - Score evaluate_unstoppable_pawns(const Position& pos, 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))); - } - - // evaluate_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 scaled by a weight taken from the - // material hash table. The aim is to improve play on game opening. + // twice. Finally, the space bonus is multiplied by a weight. The aim is to + // improve play on game opening. template - int evaluate_space(const Position& pos, const EvalInfo& ei) { + Score evaluate_space(const Position& pos, const EvalInfo& ei) { const Color Them = (Us == WHITE ? BLACK : WHITE); @@ -906,110 +686,246 @@ Value do_evaluate(const Position& pos) { assert(unsigned(safe >> (Us == WHITE ? 32 : 0)) == 0); // Count safe + (behind & safe) with a single popcount - return popcount((Us == WHITE ? safe << 32 : safe >> 32) | (behind & safe)); + int bonus = popcount((Us == WHITE ? safe << 32 : safe >> 32) | (behind & safe)); + int weight = pos.count(Us) + pos.count(Us) + + pos.count(Them) + pos.count(Them); + + return make_score(bonus * weight * weight, 0); } - // 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 }; - // apply_weight() weights score v by score w trying to prevent overflow - Score apply_weight(Score v, Score w) { + // 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(); - return make_score((int(mg_value(v)) * mg_value(w)) / 0x100, - (int(eg_value(v)) * eg_value(w)) / 0x100); - } + // Probe the material hash table + ei.mi = Material::probe(pos); + score += ei.mi->imbalance(); + + // 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); + score += apply_weight(ei.pi->pawns_score(), 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]; - // weight_option() computes the value of an evaluation weight, by combining - // two UCI-configurable weights (midgame and endgame) with an internal weight. + // 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)) }; - Score weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight) { + // Evaluate pieces and mobility + score += evaluate_pieces(pos, ei, mobility, mobilityArea); + score += apply_weight(mobility[WHITE] - mobility[BLACK], Weights[Mobility]); - // Scale option value from 100 to 256 - int mg = Options[mgOpt] * 256 / 100; - int eg = Options[egOpt] * 256 / 100; + // 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); - return apply_weight(make_score(mg, eg), internalWeight); + // 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)) + { + Bitboard b; + if ((b = ei.pi->passed_pawns(WHITE)) != 0) + score += int(relative_rank(WHITE, frontmost_sq(WHITE, b))) * Unstoppable; + + if ((b = ei.pi->passed_pawns(BLACK)) != 0) + score -= int(relative_rank(BLACK, frontmost_sq(BLACK, b))) * Unstoppable; + } + + // Evaluate space for both sides, only during opening + if (pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK) >= 2 * QueenValueMg + 4 * RookValueMg + 2 * KnightValueMg) + { + Score s = evaluate_space(pos, ei) - evaluate_space(pos, ei); + score += apply_weight(s, Weights[Space]); + } + + // 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); + + // 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()) + { + // Endgame with opposite-colored bishops and no other pieces (ignoring pawns) + // is almost a draw, in case of KBP vs KB is even more a draw. + if ( pos.non_pawn_material(WHITE) == BishopValueMg + && pos.non_pawn_material(BLACK) == BishopValueMg) + sf = more_than_one(pos.pieces(PAWN)) ? ScaleFactor(32) : ScaleFactor(8); + + // 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(50 * sf / SCALE_FACTOR_NORMAL); + } + // Endings where weaker side can place his king in front of the opponent's + // pawns are drawish. + else if ( abs(eg_value(score)) <= BishopValueEg + && ei.pi->pawn_span(strongSide) <= 1 + && !pos.pawn_passed(~strongSide, pos.king_square(~strongSide))) + sf = ei.pi->pawn_span(strongSide) ? ScaleFactor(56) : ScaleFactor(38); + } + + // 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; + + v /= int(PHASE_MIDGAME); + + // In case of tracing add all single evaluation contributions for both white and black + if (Trace) + { + Tracing::write(Tracing::MATERIAL, pos.psq_score()); + Tracing::write(Tracing::IMBALANCE, ei.mi->imbalance()); + Tracing::write(PAWN, ei.pi->pawns_score()); + Tracing::write(Tracing::MOBILITY, apply_weight(mobility[WHITE], Weights[Mobility]) + , apply_weight(mobility[BLACK], Weights[Mobility])); + Tracing::write(Tracing::SPACE, apply_weight(evaluate_space(pos, ei), Weights[Space]) + , apply_weight(evaluate_space(pos, ei), Weights[Space])); + Tracing::write(Tracing::TOTAL, score); + Tracing::ei = ei; + Tracing::sf = sf; + } + + return (pos.side_to_move() == WHITE ? v : -v) + Eval::Tempo; } // 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::write(int idx, Color c, Score s) { scores[c][idx] = s; } - void Tracing::add_term(int idx, Score wScore, Score bScore) { + void Tracing::write(int idx, Score w, Score b) { - terms[WHITE][idx] = wScore; - terms[BLACK][idx] = bScore; + write(idx, WHITE, w); + write(idx, BLACK, b); } - void Tracing::format_row(std::stringstream& ss, const char* name, int idx) { + void Tracing::print(std::stringstream& ss, const char* name, int idx) { - Score wScore = terms[WHITE][idx]; - Score bScore = terms[BLACK][idx]; + Score wScore = scores[WHITE][idx]; + Score bScore = scores[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"; } } std::string Tracing::do_trace(const Position& pos) { - std::memset(terms, 0, sizeof(terms)); + std::memset(scores, 0, sizeof(scores)); 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"; - - format_row(ss, "Material, PST, Tempo", PST); - format_row(ss, "Material imbalance", IMBALANCE); - format_row(ss, "Pawns", PAWN); - format_row(ss, "Knights", KNIGHT); - format_row(ss, "Bishops", BISHOP); - format_row(ss, "Rooks", ROOK); - format_row(ss, "Queens", QUEEN); - format_row(ss, "Mobility", MOBILITY); - format_row(ss, "King safety", KING); - format_row(ss, "Threats", THREAT); - format_row(ss, "Passed pawns", PASSED); - format_row(ss, "Space", SPACE); - - 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 << std::showpoint << std::noshowpos << std::fixed << std::setprecision(2) + << " Eval term | White | Black | Total \n" + << " | MG EG | MG EG | MG EG \n" + << "----------------+-------------+-------------+-------------\n"; + + print(ss, "Material", MATERIAL); + print(ss, "Imbalance", IMBALANCE); + print(ss, "Pawns", PAWN); + print(ss, "Knights", KNIGHT); + print(ss, "Bishops", BISHOP); + print(ss, "Rooks", ROOK); + print(ss, "Queens", QUEEN); + print(ss, "Mobility", MOBILITY); + print(ss, "King safety", KING); + print(ss, "Threats", THREAT); + print(ss, "Passed pawns", PASSED); + print(ss, "Space", SPACE); + + ss << "----------------+-------------+-------------+-------------\n"; + print(ss, "Total", TOTAL); + + 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); + } + + + /// 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, usually at startup + + void init() { + + const int MaxSlope = 8700; + const int Peak = 1280000; + int t = 0; + + for (int i = 0; i < 400; ++i) + { + t = std::min(Peak, std::min(i * i * 27, t + MaxSlope)); + KingDanger[i] = apply_weight(make_score(t / 1000, 0), Weights[KingSafety]); + } + } + +} // namespace Eval