X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fevaluate.cpp;h=f17c575d2cfeb775a5c54afacf6875988becde80;hp=25ee79ead4df1ca94f1ddbe95d62a36b49496c84;hb=6b354305e1ff27fcfa65c57ed92bd03160c3d5ca;hpb=1f40cd6d02374277abb5620d88d6fe58d7e9d6f7 diff --git a/src/evaluate.cpp b/src/evaluate.cpp index 25ee79ea..f17c575d 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) 2008-2013 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2008-2014 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 @@ -17,10 +17,10 @@ along with this program. If not, see . */ +#include #include #include #include -#include #include "bitcount.h" #include "evaluate.h" @@ -31,20 +31,6 @@ namespace { - enum ExtendedPieceType { // Used for tracing - PST = 8, IMBALANCE, MOBILITY, THREAT, PASSED, UNSTOPPABLE, SPACE, TOTAL - }; - - namespace Tracing { - - Score scores[COLOR_NB][TOTAL + 1]; - std::stringstream stream; - - void add(int idx, Score term_w, Score term_b = SCORE_ZERO); - void row(const char* name, int idx); - std::string do_trace(const Position& pos); - } - // Struct EvalInfo contains various information computed and collected // by the evaluation functions. struct EvalInfo { @@ -83,54 +69,59 @@ namespace { // king is on g8 and there's a white knight on g5, this knight adds // 2 to kingAdjacentZoneAttacksCount[BLACK]. int kingAdjacentZoneAttacksCount[COLOR_NB]; + + Bitboard pinnedPieces[COLOR_NB]; }; - // Evaluation grain size, must be a power of 2 - const int GrainSize = 4; + namespace Tracing { - // Evaluation weights, initialized from UCI options - enum { Mobility, PawnStructure, PassedPawns, Space, KingDangerUs, KingDangerThem }; - Score Weights[6]; + enum Terms { // First 8 entries are for PieceType + MATERIAL = 8, IMBALANCE, MOBILITY, THREAT, PASSED, SPACE, TOTAL, TERMS_NB + }; - typedef Value V; - #define S(mg, eg) make_score(mg, eg) + Score terms[COLOR_NB][TERMS_NB]; + EvalInfo ei; + ScaleFactor sf; - // 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) + 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); + std::string do_trace(const Position& pos); + } + + // 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) + // 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( 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( 60, 55), S( 68, 63), S(74, 68), S(77, 72), S(80, 75), S(82, 77), - S( 84, 79), S( 86, 81), S(87, 82), S(87, 82) }, - { S(-17,-33), S(-11,-16), 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(38,124) }, - { 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( 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), S(25, 41), S(25, 41), - S( 25, 41), S( 25, 41) } + {}, {}, + { 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(-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(-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(-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) } }; - // Outpost[PieceType][Square] contains bonuses of knights and bishops, indexed - // by piece type and square (from white's point of view). + // Outpost[PieceType][Square] contains bonuses for knights and bishops outposts, + // indexed by piece type and square (from white's point of view). const Value Outpost[][SQUARE_NB] = { - { - // A B C D E F G H + {// A B C D E F G H V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // Knights V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(4), V(8), V(8), V(4), V(0), V(0), @@ -149,283 +140,70 @@ namespace { // 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( 0, 0), S(24, 49), S(41,100), S(41,100) }, // KNIGHT - { S(0, 0), S( 7, 39), S(24, 49), S( 0, 0), S(41,100), S(41,100) }, // BISHOP - { S(0, 0), S( 0, 22), S(15, 49), S(15, 49), S( 0, 0), S(24, 49) }, // ROOK - { S(0, 0), S(15, 39), S(15, 39), S(15, 39), S(15, 39), S( 0, 0) } // QUEEN + { 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 }; // 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) }; + // Hanging contains a bonus for each enemy hanging piece + const Score Hanging = S(23, 20); + #undef S - const Score Tempo = make_score(24, 11); - const Score BishopPin = make_score(66, 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 UndefendedMinor = make_score(25, 10); + const Score MinorBehindPawn = make_score(16, 0); const Score TrappedRook = make_score(90, 0); + const Score Unstoppable = make_score( 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 = make_score(50, 50); - // The SpaceMask[Color] contains the area of the board which is considered - // by the space evaluation. In the middle game, each side is given a bonus + // SpaceMask[Color] contains the area of the board which is considered + // by the space evaluation. In the middlegame, each side is given a bonus // based on how many squares inside this area are safe and available for // friendly minor pieces. const Bitboard SpaceMask[] = { - (1ULL << SQ_C2) | (1ULL << SQ_D2) | (1ULL << SQ_E2) | (1ULL << SQ_F2) | - (1ULL << SQ_C3) | (1ULL << SQ_D3) | (1ULL << SQ_E3) | (1ULL << SQ_F3) | - (1ULL << SQ_C4) | (1ULL << SQ_D4) | (1ULL << SQ_E4) | (1ULL << SQ_F4), - (1ULL << SQ_C7) | (1ULL << SQ_D7) | (1ULL << SQ_E7) | (1ULL << SQ_F7) | - (1ULL << SQ_C6) | (1ULL << SQ_D6) | (1ULL << SQ_E6) | (1ULL << SQ_F6) | - (1ULL << SQ_C5) | (1ULL << SQ_D5) | (1ULL << SQ_E5) | (1ULL << SQ_F5) + (FileCBB | FileDBB | FileEBB | FileFBB) & (Rank2BB | Rank3BB | Rank4BB), + (FileCBB | FileDBB | FileEBB | FileFBB) & (Rank7BB | Rank6BB | Rank5BB) }; // King danger constants and variables. The king danger scores are taken - // from the 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[]. + // from 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 }; // Bonuses for enemy's safe checks - const int QueenContactCheck = 6; - const int RookContactCheck = 4; - const int QueenCheck = 3; - const int RookCheck = 2; - const int BishopCheck = 1; - const int KnightCheck = 1; - - // KingExposed[Square] contains penalties based on the position of the - // defending king, indexed by king's square (from white's point of view). - const int KingExposed[] = { - 2, 0, 2, 5, 5, 2, 0, 2, - 2, 2, 4, 8, 8, 4, 2, 2, - 7, 10, 12, 12, 12, 12, 10, 7, - 15, 15, 15, 15, 15, 15, 15, 15, - 15, 15, 15, 15, 15, 15, 15, 15, - 15, 15, 15, 15, 15, 15, 15, 15, - 15, 15, 15, 15, 15, 15, 15, 15, - 15, 15, 15, 15, 15, 15, 15, 15 - }; - - // 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, Value& margin); - - template - void init_eval_info(const Position& pos, EvalInfo& ei); - - template - Score evaluate_pieces_of_color(const Position& pos, EvalInfo& ei, Score& mobility); - - template - Score evaluate_king(const Position& pos, EvalInfo& ei, Value margins[]); - - template - Score evaluate_threats(const Position& pos, EvalInfo& ei); - - template - Score evaluate_passed_pawns(const Position& pos, EvalInfo& ei); - - template - int evaluate_space(const Position& pos, EvalInfo& ei); - - Score evaluate_unstoppable_pawns(const Position& pos, 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); - double to_cp(Value v); -} - - -namespace Eval { - - /// evaluate() is the main evaluation function. It always computes two - /// values, an endgame score and a middle game score, and interpolates - /// between them based on the remaining material. - - Value evaluate(const Position& pos, Value& margin) { - return do_evaluate(pos, margin); - } - - - /// trace() is like evaluate() but instead of a value returns a string suitable - /// to be print on stdout with the detailed descriptions and values of each - /// evaluation term. Used mainly 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]); - } + 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[attackUnits] contains the actual king danger weighted + // scores, indexed by a calculated integer number. + Score KingDanger[128]; + + const int ScalePawnSpan[2] = { 38, 56 }; + + // 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); } -} // namespace Eval - - -namespace { - -template -Value do_evaluate(const Position& pos, Value& margin) { - - assert(!pos.checkers()); - - EvalInfo ei; - Value margins[COLOR_NB]; - Score score, mobilityWhite, mobilityBlack; - Thread* th = pos.this_thread(); - - // margins[] store the uncertainty estimation of position's evaluation - // that typically is used by the search for pruning decisions. - margins[WHITE] = margins[BLACK] = VALUE_ZERO; - - // Initialize score by reading the incrementally updated scores included - // in the position object (material + piece square tables) and adding - // 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, th->materialTable, th->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()) - { - margin = VALUE_ZERO; - return ei.mi->evaluate(pos); - } - - // Probe the pawn hash table - ei.pi = Pawns::probe(pos, th->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_of_color(pos, ei, mobilityWhite) - - evaluate_pieces_of_color(pos, ei, mobilityBlack); - - score += apply_weight(mobilityWhite - mobilityBlack, 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, margins) - - evaluate_king(pos, ei, margins); - - // 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, check whether exists any unstoppable passed pawn - if (!pos.non_pawn_material(WHITE) || !pos.non_pawn_material(BLACK)) - score += evaluate_unstoppable_pawns(pos, ei); - - // Evaluate space for both sides, only in middle-game. - 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 that what 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) - { - // Only the two bishops ? - 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); - } - - margin = margins[pos.side_to_move()]; - 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(PST, pos.psq_score()); - Tracing::add(IMBALANCE, ei.mi->material_value()); - Tracing::add(PAWN, ei.pi->pawns_value()); - Tracing::add(UNSTOPPABLE, evaluate_unstoppable_pawns(pos, ei)); - Score w = ei.mi->space_weight() * evaluate_space(pos, ei); - Score b = ei.mi->space_weight() * evaluate_space(pos, ei); - Tracing::add(SPACE, apply_weight(w, Weights[Space]), apply_weight(b, Weights[Space])); - Tracing::add(TOTAL, score); - Tracing::stream << "\nUncertainty margin: White: " << to_cp(margins[WHITE]) - << ", Black: " << to_cp(margins[BLACK]) - << "\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); - } - - 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. @@ -436,35 +214,38 @@ Value do_evaluate(const Position& pos, Value& margin) { const Color Them = (Us == WHITE ? BLACK : WHITE); const Square Down = (Us == WHITE ? DELTA_S : DELTA_N); + 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) { ei.kingRing[Them] = b | shift_bb(b); b &= ei.attackedBy[Us][PAWN]; - ei.kingAttackersCount[Us] = b ? popcount(b) / 2 : 0; + ei.kingAttackersCount[Us] = b ? popcount(b) : 0; ei.kingAdjacentZoneAttacksCount[Us] = ei.kingAttackersWeight[Us] = 0; - } else + } + else ei.kingRing[Them] = ei.kingAttackersCount[Us] = 0; } - // evaluate_outposts() evaluates bishop and knight outposts squares + // evaluate_outpost() evaluates bishop and knight outpost squares - template - Score evaluate_outposts(const Position& pos, EvalInfo& ei, Square s) { + template + Score evaluate_outpost(const Position& pos, const EvalInfo& ei, Square s) { const Color Them = (Us == WHITE ? BLACK : WHITE); - assert (Piece == BISHOP || Piece == KNIGHT); + assert (Pt == BISHOP || Pt == KNIGHT); // Initial bonus based on square - Value bonus = Outpost[Piece == BISHOP][relative_square(Us, s)]; + Value bonus = Outpost[Pt == BISHOP][relative_square(Us, s)]; // Increase bonus if supported by pawn, especially if the opponent has - // no minor piece which can exchange the outpost piece. + // no minor piece which can trade with the outpost piece. if (bonus && (ei.attackedBy[Us][PAWN] & s)) { if ( !pos.pieces(Them, KNIGHT) @@ -473,201 +254,136 @@ Value do_evaluate(const Position& pos, Value& margin) { else bonus += bonus / 2; } + return make_score(bonus, bonus); } - // evaluate_pieces<>() assigns bonuses and penalties to the pieces of a given color + // evaluate_pieces() assigns bonuses and penalties to the pieces of a given color - template - Score evaluate_pieces(const Position& pos, EvalInfo& ei, Score& mobility, Bitboard mobilityArea) { + template + 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); + const Square* pl = pos.list(Us); - ei.attackedBy[Us][Piece] = 0; + ei.attackedBy[Us][Pt] = 0; while ((s = *pl++) != SQ_NONE) { // Find attacked squares, including x-ray attacks for bishops and rooks - b = Piece == BISHOP ? attacks_bb(s, pos.pieces() ^ pos.pieces(Us, QUEEN)) - : Piece == ROOK ? attacks_bb< ROOK>(s, pos.pieces() ^ pos.pieces(Us, ROOK, QUEEN)) - : pos.attacks_from(s); + 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)) + : pos.attacks_from(s); - ei.attackedBy[Us][Piece] |= b; + if (ei.pinnedPieces[Us] & s) + b &= LineBB[pos.king_square(Us)][s]; + + ei.attackedBy[Us][ALL_PIECES] |= ei.attackedBy[Us][Pt] |= b; if (b & ei.kingRing[Them]) { ei.kingAttackersCount[Us]++; - ei.kingAttackersWeight[Us] += KingAttackWeights[Piece]; - Bitboard bb = (b & ei.attackedBy[Them][KING]); + ei.kingAttackersWeight[Us] += KingAttackWeights[Pt]; + Bitboard bb = b & ei.attackedBy[Them][KING]; if (bb) ei.kingAdjacentZoneAttacksCount[Us] += popcount(bb); } - int mob = Piece != 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 += MobilityBonus[Piece][mob]; + mobility[Us] += MobilityBonus[Pt][mob]; - // Decrease score if we are attacked by an enemy pawn. Remaining part + // Decrease score if we are attacked by an enemy pawn. The remaining part // of threat evaluation must be done later when we have full attack info. if (ei.attackedBy[Them][PAWN] & s) - score -= ThreatenedByPawn[Piece]; - - // Otherwise give a bonus if we are a bishop and can pin a piece or can - // give a discovered check through an x-ray attack. - else if ( Piece == BISHOP - && (PseudoAttacks[Piece][pos.king_square(Them)] & s) - && !more_than_one(BetweenBB[s][pos.king_square(Them)] & pos.pieces())) - score += BishopPin; - - // Penalty for bishop with same coloured pawns - if (Piece == BISHOP) - score -= BishopPawns * ei.pi->pawns_on_same_color_squares(Us, s); - - // Bishop and knight outposts squares - if ( (Piece == BISHOP || Piece == KNIGHT) - && !(pos.pieces(Them, PAWN) & pawn_attack_span(Us, s))) - score += evaluate_outposts(pos, ei, s); - - if ( (Piece == ROOK || Piece == QUEEN) - && relative_rank(Us, s) >= RANK_5) + score -= ThreatenedByPawn[Pt]; + + if (Pt == BISHOP || Pt == KNIGHT) { - // 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 += Piece == 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) * (Piece == ROOK ? RookOnPawn : QueenOnPawn); + // Penalty for bishop with same colored pawns + if (Pt == BISHOP) + score -= BishopPawns * ei.pi->pawns_on_same_color_squares(Us, s); + + // Bishop and knight outpost square + if (!(pos.pieces(Them, PAWN) & pawn_attack_span(Us, s))) + score += evaluate_outpost(pos, ei, s); + + // Bishop or knight behind a pawn + if ( relative_rank(Us, s) < RANK_5 + && (pos.pieces(PAWN) & (s + pawn_push(Us)))) + score += MinorBehindPawn; } - // Special extra evaluation for rooks - if (Piece == ROOK) + 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); - // Penalize rooks which are trapped inside a king. Penalize more if - // king has lost right to castle. + // 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); + && !ei.pi->semiopen_side(Us, file_of(ksq), file_of(s) < file_of(ksq))) + score -= (TrappedRook - make_score(mob * 8, 0)) * (1 + !pos.can_castle(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 ( Piece == BISHOP + if ( Pt == BISHOP && pos.is_chess960() && (s == relative_square(Us, SQ_A1) || s == relative_square(Us, SQ_H1))) { - const enum Piece P = make_piece(Us, PAWN); Square d = pawn_push(Us) + (file_of(s) == FILE_A ? DELTA_E : DELTA_W); - if (pos.piece_on(s + d) == P) - score -= !pos.is_empty(s + d + pawn_push(Us)) ? TrappedBishopA1H1 * 4 - : pos.piece_on(s + d + d) == P ? TrappedBishopA1H1 * 2 - : TrappedBishopA1H1; + 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 (Trace) - Tracing::scores[Us][Piece] = score; + Tracing::terms[Us][Pt] = score; - return score; + return score - evaluate_pieces(pos, ei, mobility, mobilityArea); } - - // evaluate_threats<>() assigns bonuses according to the type of attacking piece - // and the type of attacked one. - - template - Score evaluate_threats(const Position& pos, EvalInfo& ei) { - - const Color Them = (Us == WHITE ? BLACK : WHITE); - - Bitboard b, undefendedMinors, weakEnemies; - Score score = SCORE_ZERO; - - // Undefended minors get penalized even if not under attack - undefendedMinors = pos.pieces(Them, BISHOP, KNIGHT) - & ~ei.attackedBy[Them][ALL_PIECES]; - - if (undefendedMinors) - score += UndefendedMinor; - - // Enemy pieces not defended by a pawn and under our attack - weakEnemies = pos.pieces(Them) - & ~ei.attackedBy[Them][PAWN] - & ei.attackedBy[Us][ALL_PIECES]; - - // Add bonus according to type of attacked enemy piece and to the - // type of attacking piece, from knights to queens. Kings are not - // considered because are already handled in king evaluation. - if (weakEnemies) - for (PieceType pt1 = KNIGHT; pt1 < KING; pt1++) - { - b = ei.attackedBy[Us][pt1] & weakEnemies; - if (b) - for (PieceType pt2 = PAWN; pt2 < KING; pt2++) - if (b & pos.pieces(pt2)) - score += Threat[pt1][pt2]; - } - - if (Trace) - Tracing::scores[Us][THREAT] = score; - - 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_pieces_of_color<>() assigns bonuses and penalties to all the - // pieces of a given color. + // evaluate_king() assigns bonuses and penalties to a king of a given color template - Score evaluate_pieces_of_color(const Position& pos, EvalInfo& ei, Score& mobility) { - - const Color Them = (Us == WHITE ? BLACK : WHITE); - - Score score = mobility = SCORE_ZERO; - - // 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 += evaluate_pieces(pos, ei, mobility, mobilityArea); - score += evaluate_pieces(pos, ei, mobility, mobilityArea); - score += evaluate_pieces(pos, ei, mobility, mobilityArea); - score += evaluate_pieces(pos, ei, mobility, mobilityArea); - - // Sum up all attacked squares - 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::scores[Us][MOBILITY] = apply_weight(mobility, Weights[Mobility]); - - return score; - } - - - // evaluate_king<>() assigns bonuses and penalties to a king of a given color - - template - Score evaluate_king(const Position& pos, EvalInfo& ei, Value margins[]) { + Score evaluate_king(const Position& pos, const EvalInfo& ei) { const Color Them = (Us == WHITE ? BLACK : WHITE); @@ -678,61 +394,60 @@ Value do_evaluate(const Position& pos, Value& margin) { // King shelter and enemy pawns storm Score score = ei.pi->king_safety(pos, ksq); - // King safety. This is quite complicated, and is almost certainly far - // from optimally tuned. - if ( ei.kingAttackersCount[Them] >= 2 - && ei.kingAdjacentZoneAttacksCount[Them]) + // Main king safety evaluation + if (ei.kingAttackersCount[Them]) { - // Find the attacked squares around the king which has no defenders + // Find the attacked squares around the king which have no defenders // apart from the king itself - undefended = ei.attackedBy[Them][ALL_PIECES] & ei.attackedBy[Us][KING]; - undefended &= ~( ei.attackedBy[Us][PAWN] | ei.attackedBy[Us][KNIGHT] + undefended = ei.attackedBy[Them][ALL_PIECES] + & ei.attackedBy[Us][KING] + & ~( ei.attackedBy[Us][PAWN] | ei.attackedBy[Us][KNIGHT] | ei.attackedBy[Us][BISHOP] | ei.attackedBy[Us][ROOK] | ei.attackedBy[Us][QUEEN]); // Initialize the 'attackUnits' variable, which is used later on as an // index to 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, the square of the - // king, and the quality of the pawn shelter. - attackUnits = std::min(25, (ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them]) / 2) + // 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)) - + KingExposed[relative_square(Us, ksq)] + + 2 * (ei.pinnedPieces[Us] != 0) - mg_value(score) / 32; - // Analyse enemy's safe queen contact checks. First find undefended - // squares around the king attacked by enemy queen... + // Analyse the enemy's safe queen contact checks. Firstly, find the + // undefended squares around the king that are attacked by the enemy's + // queen... b = undefended & ei.attackedBy[Them][QUEEN] & ~pos.pieces(Them); if (b) { - // ...then remove squares not supported by another enemy piece + // ...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]); + if (b) - attackUnits += QueenContactCheck - * popcount(b) - * (Them == pos.side_to_move() ? 2 : 1); + attackUnits += QueenContactCheck * popcount(b); } - // Analyse enemy's safe rook contact checks. First find undefended - // squares around the king attacked by enemy rooks... + // Analyse the enemy's safe rook contact checks. Firstly, find the + // undefended squares around the king that are attacked by the enemy's + // rooks... b = undefended & ei.attackedBy[Them][ROOK] & ~pos.pieces(Them); - // Consider only squares where the enemy rook gives check + // Consider only squares where the enemy's rook gives check b &= PseudoAttacks[ROOK][ksq]; if (b) { - // ...then remove squares not supported by another enemy piece + // ...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][QUEEN]); + if (b) - attackUnits += RookContactCheck - * popcount(b) - * (Them == pos.side_to_move() ? 2 : 1); + attackUnits += RookContactCheck * popcount(b); } - // Analyse enemy's safe distance checks for sliders and knights + // Analyse the enemy's safe distance checks for sliders and knights safe = ~(pos.pieces(Them) | ei.attackedBy[Us][ALL_PIECES]); b1 = pos.attacks_from(ksq) & safe; @@ -762,29 +477,72 @@ Value do_evaluate(const Position& pos, Value& margin) { attackUnits = std::min(99, std::max(0, attackUnits)); // Finally, extract the king danger score from the KingDanger[] - // array and subtract the score from evaluation. Set also margins[] - // value that will be used for pruning because this value can sometimes - // be very big, and so capturing a single attacking piece can therefore - // result in a score change far bigger than the value of the captured piece. - score -= KingDanger[Us == Search::RootColor][attackUnits]; - margins[Us] += mg_value(KingDanger[Us == Search::RootColor][attackUnits]); + // array and subtract the score from evaluation. + score -= KingDanger[attackUnits]; + } + + if (Trace) + Tracing::terms[Us][KING] = score; + + return score; + } + + + // evaluate_threats() assigns bonuses according to the type of attacking piece + // and the type of attacked one. + + template + Score evaluate_threats(const Position& pos, const EvalInfo& ei) { + + const Color Them = (Us == WHITE ? BLACK : WHITE); + + Bitboard b, weakEnemies, protectedEnemies; + Score score = SCORE_ZERO; + + // Protected enemies + protectedEnemies = (pos.pieces(Them) ^ pos.pieces(Them,PAWN)) + & ei.attackedBy[Them][PAWN] + & (ei.attackedBy[Us][KNIGHT] | ei.attackedBy[Us][BISHOP]); + + if(protectedEnemies) + score += Threat[0][type_of(pos.piece_on(lsb(protectedEnemies)))]; + + // Enemies not defended by a pawn and under our attack + weakEnemies = 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) + { + b = weakEnemies & (ei.attackedBy[Us][KNIGHT] | ei.attackedBy[Us][BISHOP]); + if (b) + score += Threat[0][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)))]; + + b = weakEnemies & ~ei.attackedBy[Them][ALL_PIECES]; + if (b) + score += more_than_one(b) ? Hanging * popcount(b) : Hanging; } if (Trace) - Tracing::scores[Us][KING] = score; + Tracing::terms[Us][Tracing::THREAT] = score; return score; } - // evaluate_passed_pawns<>() evaluates the passed pawns of the given color + // evaluate_passed_pawns() evaluates the passed pawns of the given color template - Score evaluate_passed_pawns(const Position& pos, EvalInfo& ei) { + Score evaluate_passed_pawns(const Position& pos, const EvalInfo& ei) { 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); @@ -793,32 +551,30 @@ Value do_evaluate(const Position& pos, Value& margin) { { Square s = pop_lsb(&b); - assert(pos.pawn_is_passed(Us, s)); + 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 kings proximity - ebonus += Value(square_distance(pos.king_square(Them), blockSq) * 5 * rr); - ebonus -= Value(square_distance(pos.king_square(Us), blockSq) * 2 * rr); + // Adjust bonus based on the king's proximity + 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 (rank_of(blockSq) != (Us == WHITE ? RANK_8 : RANK_1)) - ebonus -= Value(square_distance(pos.king_square(Us), blockSq + pawn_push(Us)) * rr); + if (relative_rank(Us, blockSq) != RANK_8) + ebonus -= square_distance(pos.king_square(Us), blockSq + pawn_push(Us)) * rr; - // If the pawn is free to advance, increase bonus - if (pos.is_empty(blockSq)) + // If the pawn is free to advance, then increase the bonus + if (pos.empty(blockSq)) { squaresToQueen = forward_bb(Us, s); - defendedSquares = squaresToQueen & ei.attackedBy[Us][ALL_PIECES]; // 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 @@ -829,351 +585,314 @@ Value do_evaluate(const Position& pos, Value& margin) { else unsafeSquares = squaresToQueen & (ei.attackedBy[Them][ALL_PIECES] | pos.pieces(Them)); - // If there aren't enemy attacks huge bonus, a bit smaller if at - // least block square is not attacked, otherwise smallest bonus. - int k = !unsafeSquares ? 15 : !(unsafeSquares & blockSq) ? 9 : 3; + 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, assign a big bonus. Otherwise + // assign a smaller bonus if the block square isn't attacked. + int k = !unsafeSquares ? 15 : !(unsafeSquares & blockSq) ? 9 : 0; - // Big bonus if the path to queen is fully defended, a bit less - // if at least block square is defended. + // 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; } } // 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; - } - score += make_score(mbonus, ebonus); + if (pos.count(Us) < pos.count(Them)) + ebonus += ebonus / 4; + score += make_score(mbonus, ebonus); } if (Trace) - Tracing::scores[Us][PASSED] = apply_weight(score, Weights[PassedPawns]); + Tracing::terms[Us][Tracing::PASSED] = apply_weight(score, Weights[PassedPawns]); - // Add the scores to the middle game and endgame eval + // Add the scores to the middlegame and endgame eval return apply_weight(score, Weights[PassedPawns]); } - // evaluate_unstoppable_pawns() evaluates the unstoppable passed pawns for both sides, this is quite - // conservative and returns a winning score only when we are very sure that the pawn is winning. + // evaluate_unstoppable_pawns() scores the most advanced among the passed and + // 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, EvalInfo& ei) { + Score evaluate_unstoppable_pawns(Color us, const EvalInfo& ei) { - Bitboard b, b2, blockers, supporters, queeningPath, candidates; - Square s, blockSq, queeningSquare; - Color c, winnerSide, loserSide; - bool pathDefended, opposed; - int pliesToGo, movesToGo, oppMovesToGo, sacptg, blockersCount, minKingDist, kingptg, d; - int pliesToQueen[] = { 256, 256 }; + Bitboard b = ei.pi->passed_pawns(us) | ei.pi->candidate_pawns(us); - // Step 1. Hunt for unstoppable passed pawns. If we find at least one, - // record how many plies are required for promotion. - for (c = WHITE; c <= BLACK; c++) - { - // Skip if other side has non-pawn pieces - if (pos.non_pawn_material(~c)) - continue; - - b = ei.pi->passed_pawns(c); + return b ? Unstoppable * int(relative_rank(us, frontmost_sq(us, b))) : SCORE_ZERO; + } - while (b) - { - s = pop_lsb(&b); - queeningSquare = relative_square(c, file_of(s) | RANK_8); - queeningPath = forward_bb(c, s); - // Compute plies to queening and check direct advancement - movesToGo = rank_distance(s, queeningSquare) - int(relative_rank(c, s) == RANK_2); - oppMovesToGo = square_distance(pos.king_square(~c), queeningSquare) - int(c != pos.side_to_move()); - pathDefended = ((ei.attackedBy[c][ALL_PIECES] & queeningPath) == queeningPath); + // 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. + template + int evaluate_space(const Position& pos, const EvalInfo& ei) { - if (movesToGo >= oppMovesToGo && !pathDefended) - continue; + const Color Them = (Us == WHITE ? BLACK : WHITE); - // Opponent king cannot block because path is defended and position - // is not in check. So only friendly pieces can be blockers. - assert(!pos.checkers()); - assert((queeningPath & pos.pieces()) == (queeningPath & pos.pieces(c))); + // 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[Us] + & ~pos.pieces(Us, PAWN) + & ~ei.attackedBy[Them][PAWN] + & (ei.attackedBy[Us][ALL_PIECES] | ~ei.attackedBy[Them][ALL_PIECES]); - // Add moves needed to free the path from friendly pieces and retest condition - movesToGo += popcount(queeningPath & pos.pieces(c)); + // 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); - if (movesToGo >= oppMovesToGo && !pathDefended) - continue; + // Since SpaceMask[Us] is fully on our half of the board + assert(unsigned(safe >> (Us == WHITE ? 32 : 0)) == 0); - pliesToGo = 2 * movesToGo - int(c == pos.side_to_move()); - pliesToQueen[c] = std::min(pliesToQueen[c], pliesToGo); - } - } + // Count safe + (behind & safe) with a single popcount + return popcount((Us == WHITE ? safe << 32 : safe >> 32) | (behind & safe)); + } - // Step 2. If either side cannot promote at least three plies before the other side then situation - // becomes too complex and we give up. Otherwise we determine the possibly "winning side" - if (abs(pliesToQueen[WHITE] - pliesToQueen[BLACK]) < 3) - return SCORE_ZERO; - winnerSide = (pliesToQueen[WHITE] < pliesToQueen[BLACK] ? WHITE : BLACK); - loserSide = ~winnerSide; + // do_evaluate() is the evaluation entry point, called directly from evaluate() - // Step 3. Can the losing side possibly create a new passed pawn and thus prevent the loss? - b = candidates = pos.pieces(loserSide, PAWN); + template + Value do_evaluate(const Position& pos) { - while (b) - { - s = pop_lsb(&b); + assert(!pos.checkers()); - // Compute plies from queening - queeningSquare = relative_square(loserSide, file_of(s) | RANK_8); - movesToGo = rank_distance(s, queeningSquare) - int(relative_rank(loserSide, s) == RANK_2); - pliesToGo = 2 * movesToGo - int(loserSide == pos.side_to_move()); + EvalInfo ei; + Score score, mobility[2] = { SCORE_ZERO, SCORE_ZERO }; + Thread* thisThread = pos.this_thread(); - // Check if (without even considering any obstacles) we're too far away or doubled - if ( pliesToQueen[winnerSide] + 3 <= pliesToGo - || (forward_bb(loserSide, s) & pos.pieces(loserSide, PAWN))) - candidates ^= s; - } + // 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(); - // If any candidate is already a passed pawn it _may_ promote in time. We give up. - if (candidates & ei.pi->passed_pawns(loserSide)) - return SCORE_ZERO; + // Probe the material hash table + ei.mi = Material::probe(pos, thisThread->materialTable, thisThread->endgames); + score += ei.mi->material_value(); - // Step 4. Check new passed pawn creation through king capturing and pawn sacrifices - b = candidates; + // 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); - while (b) - { - s = pop_lsb(&b); - sacptg = blockersCount = 0; - minKingDist = kingptg = 256; + // Probe the pawn hash table + ei.pi = Pawns::probe(pos, thisThread->pawnsTable); + score += apply_weight(ei.pi->pawns_value(), Weights[PawnStructure]); - // Compute plies from queening - queeningSquare = relative_square(loserSide, file_of(s) | RANK_8); - movesToGo = rank_distance(s, queeningSquare) - int(relative_rank(loserSide, s) == RANK_2); - pliesToGo = 2 * movesToGo - int(loserSide == pos.side_to_move()); + // Initialize attack and king safety bitboards + init_eval_info(pos, ei); + init_eval_info(pos, ei); - // Generate list of blocking pawns and supporters - supporters = adjacent_files_bb(file_of(s)) & candidates; - opposed = forward_bb(loserSide, s) & pos.pieces(winnerSide, PAWN); - blockers = passed_pawn_mask(loserSide, s) & pos.pieces(winnerSide, PAWN); + ei.attackedBy[WHITE][ALL_PIECES] |= ei.attackedBy[WHITE][KING]; + ei.attackedBy[BLACK][ALL_PIECES] |= ei.attackedBy[BLACK][KING]; - assert(blockers); + // 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)) }; - // How many plies does it take to remove all the blocking pawns? - while (blockers) - { - blockSq = pop_lsb(&blockers); - movesToGo = 256; + // Evaluate pieces and mobility + score += evaluate_pieces(pos, ei, mobility, mobilityArea); + score += apply_weight(mobility[WHITE] - mobility[BLACK], Weights[Mobility]); - // Check pawns that can give support to overcome obstacle, for instance - // black pawns: a4, b4 white: b2 then pawn in b4 is giving support. - if (!opposed) - { - b2 = supporters & in_front_bb(winnerSide, rank_of(blockSq + pawn_push(winnerSide))); + // 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); - while (b2) // This while-loop could be replaced with LSB/MSB (depending on color) - { - d = square_distance(blockSq, pop_lsb(&b2)) - 2; - movesToGo = std::min(movesToGo, d); - } - } + // Evaluate tactical threats, we need full attack information including king + score += evaluate_threats(pos, ei) + - evaluate_threats(pos, ei); - // Check pawns that can be sacrificed against the blocking pawn - b2 = pawn_attack_span(winnerSide, blockSq) & candidates & ~(1ULL << s); + // Evaluate passed pawns, we need full attack information including king + score += evaluate_passed_pawns(pos, ei) + - evaluate_passed_pawns(pos, ei); - while (b2) // This while-loop could be replaced with LSB/MSB (depending on color) - { - d = square_distance(blockSq, pop_lsb(&b2)) - 2; - movesToGo = std::min(movesToGo, d); - } + // 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); - // If obstacle can be destroyed with an immediate pawn exchange / sacrifice, - // it's not a real obstacle and we have nothing to add to pliesToGo. - if (movesToGo <= 0) - continue; + // 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]); + } - // Plies needed to sacrifice against all the blocking pawns - sacptg += movesToGo * 2; - blockersCount++; + // 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); - // Plies needed for the king to capture all the blocking pawns - d = square_distance(pos.king_square(loserSide), blockSq); - minKingDist = std::min(minKingDist, d); - kingptg = (minKingDist + blockersCount) * 2; + // 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)]); } + } - // Check if pawn sacrifice plan _may_ save the day - if (pliesToQueen[winnerSide] + 3 > pliesToGo + sacptg) - return SCORE_ZERO; + // 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; - // Check if king capture plan _may_ save the day (contains some false positives) - if (pliesToQueen[winnerSide] + 3 > pliesToGo + kingptg) - return SCORE_ZERO; + v /= int(PHASE_MIDGAME); + + // 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; } - // Winning pawn is unstoppable and will promote as first, return big score - Score score = make_score(0, (Value) 1280 - 32 * pliesToQueen[winnerSide]); - return winnerSide == WHITE ? score : -score; + return pos.side_to_move() == WHITE ? v : -v; } - // 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. - template - int evaluate_space(const Position& pos, EvalInfo& ei) { + // Tracing function definitions - const Color Them = (Us == WHITE ? BLACK : WHITE); + double Tracing::to_cp(Value v) { return double(v) / PawnValueEg; } - // 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[Us] - & ~pos.pieces(Us, PAWN) - & ~ei.attackedBy[Them][PAWN] - & (ei.attackedBy[Us][ALL_PIECES] | ~ei.attackedBy[Them][ALL_PIECES]); + void Tracing::add_term(int idx, Score wScore, Score bScore) { - // 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); + terms[WHITE][idx] = wScore; + terms[BLACK][idx] = bScore; + } - // Since SpaceMask[Us] is fully on our half of the board - assert(unsigned(safe >> (Us == WHITE ? 32 : 0)) == 0); + void Tracing::format_row(std::stringstream& ss, const char* name, int idx) { - // Count safe + (behind & safe) with a single popcount - return popcount((Us == WHITE ? safe << 32 : safe >> 32) | (behind & safe)); + Score wScore = terms[WHITE][idx]; + Score bScore = terms[BLACK][idx]; + + switch (idx) { + 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(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::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) { - // interpolate() interpolates between a middle game and an endgame score, - // based on game phase. It also scales the return value by a ScaleFactor array. + std::memset(terms, 0, sizeof(terms)); - Value interpolate(const Score& v, Phase ph, ScaleFactor sf) { + Value v = do_evaluate(pos); + v = pos.side_to_move() == WHITE ? v : -v; // White's point of view - assert(mg_value(v) > -VALUE_INFINITE && mg_value(v) < VALUE_INFINITE); - assert(eg_value(v) > -VALUE_INFINITE && eg_value(v) < VALUE_INFINITE); - assert(ph >= PHASE_ENDGAME && ph <= PHASE_MIDGAME); + 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"; - int ev = (eg_value(v) * int(sf)) / SCALE_FACTOR_NORMAL; - int result = (mg_value(v) * int(ph) + ev * int(128 - ph)) / 128; - return Value((result + GrainSize / 2) & ~(GrainSize - 1)); - } + 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); + 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); - // apply_weight() weights score v by score w trying to prevent overflow - Score apply_weight(Score v, Score w) { - return make_score((int(mg_value(v)) * mg_value(w)) / 0x100, - (int(eg_value(v)) * eg_value(w)) / 0x100); - } + ss << "----------------+-------------+-------------+-------------\n"; + format_row(ss, "Total", TOTAL); - // weight_option() computes the value of an evaluation weight, by combining - // two UCI-configurable weights (midgame and endgame) with an internal weight. + ss << "\nTotal Evaluation: " << to_cp(v) << " (white side)\n"; - Score weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight) { + return ss.str(); + } - // Scale option value from 100 to 256 - int mg = Options[mgOpt] * 256 / 100; - int eg = Options[egOpt] * 256 / 100; +} // namespace - return apply_weight(make_score(mg, eg), internalWeight); - } +namespace Eval { - // Tracing functions definitions + /// 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. - double to_cp(Value v) { return double(v) / double(PawnValueMg); } + Value evaluate(const Position& pos) { + return do_evaluate(pos) + Tempo; + } - void Tracing::add(int idx, Score wScore, Score bScore) { - scores[WHITE][idx] = wScore; - scores[BLACK][idx] = bScore; + /// 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); } - void Tracing::row(const char* name, int idx) { - Score wScore = scores[WHITE][idx]; - Score bScore = scores[BLACK][idx]; + /// init() computes evaluation weights from the corresponding UCI parameters + /// and setup king tables. - switch (idx) { - case PST: case IMBALANCE: case PAWN: case UNSTOPPABLE: case TOTAL: - stream << std::setw(20) << name << " | --- --- | --- --- | " - << std::setw(6) << to_cp(mg_value(wScore)) << " " - << std::setw(6) << to_cp(eg_value(wScore)) << " \n"; - break; - default: - stream << std::setw(20) << 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"; - } - } + void init() { - std::string Tracing::do_trace(const Position& pos) { + const double MaxSlope = 30; + const double Peak = 1280; - Search::RootColor = pos.side_to_move(); - - stream.str(""); - stream << std::showpoint << std::showpos << std::fixed << std::setprecision(2); - std::memset(scores, 0, 2 * (TOTAL + 1) * sizeof(Score)); - - Value margin; - do_evaluate(pos, margin); - - std::string totals = stream.str(); - stream.str(""); - - stream << std::setw(21) << "Eval term " << "| White | Black | Total \n" - << " | MG EG | MG EG | MG EG \n" - << "---------------------+-------------+-------------+---------------\n"; - - row("Material, PST, Tempo", PST); - row("Material imbalance", IMBALANCE); - row("Pawns", PAWN); - row("Knights", KNIGHT); - row("Bishops", BISHOP); - row("Rooks", ROOK); - row("Queens", QUEEN); - row("Mobility", MOBILITY); - row("King safety", KING); - row("Threats", THREAT); - row("Passed pawns", PASSED); - row("Unstoppable pawns", UNSTOPPABLE); - row("Space", SPACE); - - stream << "---------------------+-------------+-------------+---------------\n"; - row("Total", TOTAL); - stream << totals; - - return stream.str(); + 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