X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fevaluate.cpp;h=38f2d604ce9f05ad588631531b6119be1b2b91bc;hp=859a1c38138ae8c1284e6d92ddfce20770f7c7b0;hb=b4f6728e610848b202cee47af28fa3bb0a251e3c;hpb=800ba28e833cff47ef046637cf9e825031bb9244 diff --git a/src/evaluate.cpp b/src/evaluate.cpp index 859a1c38..177d2934 100644 --- a/src/evaluate.cpp +++ b/src/evaluate.cpp @@ -1,7 +1,8 @@ /* 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 + Copyright (C) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad Stockfish is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -17,33 +18,70 @@ along with this program. If not, see . */ +#include #include +#include // For std::memset #include #include -#include -#include "bitcount.h" +#include "bitboard.h" #include "evaluate.h" #include "material.h" #include "pawns.h" -#include "thread.h" -#include "ucioption.h" namespace { + namespace Trace { + + enum Term { // The first 8 entries are for PieceType + MATERIAL = 8, IMBALANCE, MOBILITY, THREAT, PASSED, SPACE, TOTAL, TERM_NB + }; + + double scores[TERM_NB][COLOR_NB][PHASE_NB]; + + double to_cp(Value v) { return double(v) / PawnValueEg; } + + void add(int idx, Color c, Score s) { + scores[idx][c][MG] = to_cp(mg_value(s)); + scores[idx][c][EG] = to_cp(eg_value(s)); + } + + void add(int idx, Score w, Score b = SCORE_ZERO) { + add(idx, WHITE, w); add(idx, BLACK, b); + } + + std::ostream& operator<<(std::ostream& os, Term t) { + + if (t == MATERIAL || t == IMBALANCE || t == Term(PAWN) || t == TOTAL) + os << " --- --- | --- --- | "; + else + os << std::setw(5) << scores[t][WHITE][MG] << " " + << std::setw(5) << scores[t][WHITE][EG] << " | " + << std::setw(5) << scores[t][BLACK][MG] << " " + << std::setw(5) << scores[t][BLACK][EG] << " | "; + + os << std::setw(5) << scores[t][WHITE][MG] - scores[t][BLACK][MG] << " " + << std::setw(5) << scores[t][WHITE][EG] - scores[t][BLACK][EG] << " \n"; + + return os; + } + } + + using namespace Trace; + // Struct EvalInfo contains various information computed and collected // by the evaluation functions. struct EvalInfo { - // Pointers to material and pawn hash table entries - Material::Entry* mi; - Pawns::Entry* pi; - // attackedBy[color][piece type] is a bitboard representing all squares - // attacked by a given color and piece type, attackedBy[color][ALL_PIECES] - // contains all squares attacked by the given color. + // attacked by a given color and piece type (can be also ALL_PIECES). Bitboard attackedBy[COLOR_NB][PIECE_TYPE_NB]; + // attackedBy2[color] are the squares attacked by 2 pieces of a given color, + // possibly via x-ray or by one pawn and one piece. Diagonal x-ray through + // pawn or squares attacked by 2 pawns are not explicitly added. + Bitboard attackedBy2[COLOR_NB]; + // kingRing[color] is the zone around the king which is considered // by the king safety evaluation. This consists of the squares directly // adjacent to the king, and the three (or two, for a king on an edge file) @@ -56,208 +94,156 @@ namespace { // which attack a square in the kingRing of the enemy king. int kingAttackersCount[COLOR_NB]; - // kingAttackersWeight[color] is the sum of the "weight" of the pieces of the + // kingAttackersWeight[color] is the sum of the "weights" of the pieces of the // given color which attack a square in the kingRing of the enemy king. The - // weights of the individual piece types are given by the 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]; + Material::Entry* me; + Pawns::Entry* pi; }; - namespace Tracing { - - enum Terms { // First 8 entries are for PieceType - PST = 8, IMBALANCE, MOBILITY, THREAT, PASSED, SPACE, TOTAL, TERMS_NB - }; - - Score terms[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); - std::string do_trace(const Position& pos); - } - - // Evaluation weights, initialized from UCI options - enum { Mobility, PawnStructure, PassedPawns, Space, KingDangerUs, KingDangerThem }; - struct Weight { int mg, eg; } Weights[6]; - - 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. + // game, indexed by piece type and number of attacked squares in the MobilityArea. const Score MobilityBonus[][32] = { {}, {}, - { 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) } + { S(-75,-76), S(-56,-54), S( -9,-26), S( -2,-10), S( 6, 5), S( 15, 11), // Knights + S( 22, 26), S( 30, 28), S( 36, 29) }, + { S(-48,-58), S(-21,-19), S( 16, -2), S( 26, 12), S( 37, 22), S( 51, 42), // Bishops + S( 54, 54), S( 63, 58), S( 65, 63), S( 71, 70), S( 79, 74), S( 81, 86), + S( 92, 90), S( 97, 94) }, + { S(-56,-78), S(-25,-18), S(-11, 26), S( -5, 55), S( -4, 70), S( -1, 81), // Rooks + S( 8,109), S( 14,120), S( 21,128), S( 23,143), S( 31,154), S( 32,160), + S( 43,165), S( 49,168), S( 59,169) }, + { S(-40,-35), S(-25,-12), S( 2, 7), S( 4, 19), S( 14, 37), S( 24, 55), // Queens + S( 25, 62), S( 40, 76), S( 43, 79), S( 47, 87), S( 54, 94), S( 56,102), + S( 60,111), S( 70,116), S( 72,118), S( 73,122), S( 75,128), S( 77,130), + S( 85,133), S( 94,136), S( 99,140), S(108,157), S(112,158), S(113,161), + S(118,174), S(119,177), S(123,191), S(128,199) } }; - // Outpost[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 - 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), - V(0), V(4),V(17),V(26),V(26),V(17), V(4), V(0), - V(0), V(8),V(26),V(35),V(35),V(26), V(8), V(0), - V(0), V(4),V(17),V(17),V(17),V(17), V(4), V(0) }, - { - V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // Bishops - V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), - V(0), V(0), V(5), V(5), V(5), V(5), V(0), V(0), - V(0), V(5),V(10),V(10),V(10),V(10), V(5), V(0), - V(0),V(10),V(21),V(21),V(21),V(21),V(10), V(0), - V(0), V(5), V(8), V(8), V(8), V(8), V(5), V(0) } + // Outpost[knight/bishop][supported by pawn] contains bonuses for knights and + // bishops outposts, bigger if outpost piece is supported by a pawn. + const Score Outpost[][2] = { + { S(43,11), S(65,20) }, // Knights + { S(20, 3), S(29, 8) } // Bishops + }; + + // ReachableOutpost[knight/bishop][supported by pawn] contains bonuses for + // knights and bishops which can reach an outpost square in one move, bigger + // if outpost square is supported by a pawn. + const Score ReachableOutpost[][2] = { + { S(21, 5), S(35, 8) }, // Knights + { S( 8, 0), S(14, 4) } // Bishops }; - // Threat[attacking][attacked] contains bonuses according to which piece - // type attacks which one. + // RookOnFile[semiopen/open] contains bonuses for each rook when there is no + // friendly pawn on the rook file. + const Score RookOnFile[2] = { S(20, 7), S(45, 20) }; + + // ThreatBySafePawn[PieceType] contains bonuses according to which piece + // type is attacked by a pawn which is protected or is not attacked. + const Score ThreatBySafePawn[PIECE_TYPE_NB] = { + S(0, 0), S(0, 0), S(176, 139), S(131, 127), S(217, 218), S(203, 215) }; + + // Threat[by minor/by rook][attacked PieceType] contains + // bonuses according to which piece type attacks which one. + // Attacks on lesser pieces which are pawn-defended are not considered. const Score Threat[][PIECE_TYPE_NB] = { - { S(0, 0), S( 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 + { S(0, 0), S(0, 33), S(45, 43), S(46, 47), S(72,107), S(48,118) }, // by Minor + { S(0, 0), S(0, 25), S(40, 62), S(40, 59), S( 0, 34), S(35, 48) } // by Rook }; - // 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) + // ThreatByKing[on one/on many] contains bonuses for King attacks on + // pawns or pieces which are not pawn-defended. + const Score ThreatByKing[2] = { S(3, 62), S(9, 138) }; + + // Passed[mg/eg][Rank] contains midgame and endgame bonuses for passed pawns. + // We don't use a Score because we process the two components independently. + const Value Passed[][RANK_NB] = { + { V(5), V( 5), V(31), V(73), V(166), V(252) }, + { V(7), V(14), V(38), V(73), V(166), V(252) } }; - #undef S + // PassedFile[File] contains a bonus according to the file of a passed pawn + const Score PassedFile[FILE_NB] = { + S( 9, 10), S( 2, 10), S( 1, -8), S(-20,-12), + S(-20,-12), S( 1, -8), S( 2, 10), S( 9, 10) + }; - const Score Tempo = make_score(24, 11); - const Score RookOn7th = make_score(11, 20); - const Score RookOnPawn = make_score(10, 28); - 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 MinorBehindPawn = S(16, 0); + const Score BishopPawns = S( 8, 12); + const Score RookOnPawn = S( 8, 24); + const Score TrappedRook = S(92, 0); + const Score CloseEnemies = S( 7, 0); + const Score SafeCheck = S(20, 20); + const Score OtherCheck = S(10, 10); + const Score ThreatByHangingPawn = S(71, 61); + const Score LooseEnemies = S( 0, 25); + const Score WeakQueen = S(35, 0); + const Score Hanging = S(48, 27); + const Score ThreatByPawnPush = S(38, 22); + const Score Unstoppable = S( 0, 20); // Penalty for a bishop on a1/h1 (a8/h8 for black) which is trapped by // a friendly pawn on b2/g2 (b7/g7 for black). This can obviously only // happen in Chess960 games. - const Score TrappedBishopA1H1 = make_score(50, 50); - - // 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[] = { - (FileCBB | FileDBB | FileEBB | FileFBB) & (Rank2BB | Rank3BB | Rank4BB), - (FileCBB | FileDBB | FileEBB | FileFBB) & (Rank7BB | Rank6BB | Rank5BB) - }; + const Score TrappedBishopA1H1 = S(50, 50); + + #undef S + #undef V - // 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 }; - - // 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]; - - - // 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); - } - - - // weight_option() computes the value of an evaluation weight, by combining - // two UCI-configurable weights (midgame and endgame) with an internal weight. - - Weight weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight) { - - Weight w = { Options[mgOpt] * mg_value(internalWeight) / 100, - Options[egOpt] * eg_value(internalWeight) / 100 }; - return w; - } + Score KingDanger[512]; + // KingAttackWeights[PieceType] contains king attack weights by piece type + const int KingAttackWeights[PIECE_TYPE_NB] = { 0, 0, 7, 5, 4, 1 }; - // interpolate() interpolates between a middlegame and an endgame score, - // based on game phase. It also scales the return value by a ScaleFactor array. - - Value interpolate(const Score& v, Phase ph, ScaleFactor sf) { - - 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); - - int eg = (eg_value(v) * int(sf)) / SCALE_FACTOR_NORMAL; - return Value((mg_value(v) * int(ph) + eg * int(PHASE_MIDGAME - ph)) / PHASE_MIDGAME); - } + // Penalties for enemy's safe checks + const int QueenContactCheck = 89; + const int QueenCheck = 62; + const int RookCheck = 57; + const int BishopCheck = 48; + const int KnightCheck = 78; - // init_eval_info() initializes king bitboards for given color adding - // pawn attacks. To be done at the beginning of the evaluation. + // eval_init() initializes king and attack bitboards for a given color + // adding pawn attacks. To be done at the beginning of the evaluation. template - void init_eval_info(const Position& pos, EvalInfo& ei) { + void eval_init(const Position& pos, EvalInfo& ei) { - const Color Them = (Us == WHITE ? BLACK : WHITE); + const 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][ALL_PIECES] = ei.attackedBy[Us][PAWN] = ei.pi->pawn_attacks(Us); + Bitboard b = ei.attackedBy[Them][KING]; + ei.attackedBy[Them][ALL_PIECES] |= b; + ei.attackedBy[Us][ALL_PIECES] |= ei.attackedBy[Us][PAWN] = ei.pi->pawn_attacks(Us); + ei.attackedBy2[Us] = ei.attackedBy[Us][PAWN] & ei.attackedBy[Us][KING]; // 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]; - ei.kingAttackersCount[Us] = b ? popcount(b) : 0; + ei.kingAttackersCount[Us] = popcount(b); ei.kingAdjacentZoneAttacksCount[Us] = ei.kingAttackersWeight[Us] = 0; } else @@ -265,45 +251,21 @@ namespace { } - // evaluate_outposts() evaluates bishop and knight outpost squares - - template - Score evaluate_outposts(const Position& pos, EvalInfo& ei, Square s) { - - const Color Them = (Us == WHITE ? BLACK : WHITE); - - assert (Pt == BISHOP || Pt == KNIGHT); - - // Initial bonus based on square - 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 trade with the outpost piece. - if (bonus && (ei.attackedBy[Us][PAWN] & s)) - { - if ( !pos.pieces(Them, KNIGHT) - && !(squares_of_color(s) & pos.pieces(Them, BISHOP))) - bonus += bonus + bonus / 2; - 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 and type. - template - Score evaluate_pieces(const Position& pos, EvalInfo& ei, Score* mobility, Bitboard* mobilityArea) { - - Bitboard b; + template + Score evaluate_pieces(const Position& pos, EvalInfo& ei, Score* mobility, + const Bitboard* mobilityArea) { + Bitboard b, bb; 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 Bitboard OutpostRanks = (Us == WHITE ? Rank4BB | Rank5BB | Rank6BB + : Rank5BB | Rank4BB | Rank3BB); + const Square* pl = pos.squares(Us); ei.attackedBy[Us][Pt] = 0; @@ -315,17 +277,16 @@ namespace { : pos.attacks_from(s); if (ei.pinnedPieces[Us] & s) - b &= LineBB[pos.king_square(Us)][s]; + b &= LineBB[pos.square(Us)][s]; + ei.attackedBy2[Us] |= ei.attackedBy[Us][ALL_PIECES] & b; ei.attackedBy[Us][ALL_PIECES] |= ei.attackedBy[Us][Pt] |= b; if (b & ei.kingRing[Them]) { ei.kingAttackersCount[Us]++; ei.kingAttackersWeight[Us] += KingAttackWeights[Pt]; - Bitboard bb = b & ei.attackedBy[Them][KING]; - if (bb) - ei.kingAdjacentZoneAttacksCount[Us] += popcount(bb); + ei.kingAdjacentZoneAttacksCount[Us] += popcount(b & ei.attackedBy[Them][KING]); } if (Pt == QUEEN) @@ -333,105 +294,114 @@ namespace { | ei.attackedBy[Them][BISHOP] | ei.attackedBy[Them][ROOK]); - int mob = Pt != QUEEN ? popcount(b & mobilityArea[Us]) - : popcount(b & mobilityArea[Us]); + int mob = popcount(b & mobilityArea[Us]); mobility[Us] += MobilityBonus[Pt][mob]; - // 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[Pt]; - 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 - if (!(pos.pieces(Them, PAWN) & pawn_attack_span(Us, s))) - score += evaluate_outposts(pos, ei, s); + // Bonus for outpost squares + bb = OutpostRanks & ~ei.pi->pawn_attacks_span(Them); + if (bb & s) + score += Outpost[Pt == BISHOP][!!(ei.attackedBy[Us][PAWN] & s)]; + else + { + bb &= b & ~pos.pieces(Us); + if (bb) + score += ReachableOutpost[Pt == BISHOP][!!(ei.attackedBy[Us][PAWN] & bb)]; + } - // 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) - { - // Rook 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 += RookOn7th; + // Penalty for pawns on the same color square as the bishop + if (Pt == BISHOP) + score -= BishopPawns * ei.pi->pawns_on_same_color_squares(Us, s); - // Rook piece attacking enemy pawns on the same rank/file - if (relative_rank(Us, s) >= RANK_5) + // 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))) { - Bitboard pawns = pos.pieces(Them, PAWN) & PseudoAttacks[ROOK][s]; - if (pawns) - score += popcount(pawns) * RookOnPawn; + 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; } + } - // 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 (Pt == ROOK) + { + // Bonus for aligning with enemy pawns on the same rank/file + if (relative_rank(Us, s) >= RANK_5) + score += RookOnPawn * popcount(pos.pieces(Them, PAWN) & PseudoAttacks[ROOK][s]); - if (mob > 3 || ei.pi->semiopen(Us, file_of(s))) - continue; + // Bonus when on an open or semi-open file + if (ei.pi->semiopen_file(Us, file_of(s))) + score += RookOnFile[!!ei.pi->semiopen_file(Them, file_of(s))]; - Square ksq = pos.king_square(Us); + // Penalize when trapped by the king, even more if the king cannot castle + else if (mob <= 3) + { + Square ksq = pos.square(Us); - // 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); + 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)); + } } - // 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))) + if (Pt == QUEEN) { - 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; + // Penalty if any relative pin or discovered attack against the queen + if (pos.slider_blockers(pos.pieces(Them, ROOK, BISHOP), s)) + score -= WeakQueen; } } - if (Trace) - Tracing::terms[Us][Pt] = score; + if (DoTrace) + Trace::add(Pt, Us, score); - return score - evaluate_pieces(pos, ei, mobility, mobilityArea); + // Recursively call evaluate_pieces() of next piece type until KING is excluded + return score - evaluate_pieces(pos, ei, mobility, mobilityArea); } template<> - Score evaluate_pieces(const Position&, EvalInfo&, Score*, Bitboard*) { return SCORE_ZERO; } + Score evaluate_pieces(const Position&, EvalInfo&, Score*, const Bitboard*) { return SCORE_ZERO; } template<> - Score evaluate_pieces(const Position&, EvalInfo&, Score*, Bitboard*) { return SCORE_ZERO; } + Score evaluate_pieces< true, WHITE, KING>(const Position&, EvalInfo&, Score*, const Bitboard*) { return SCORE_ZERO; } // evaluate_king() assigns bonuses and penalties to a king of a given color - template + const Bitboard WhiteCamp = Rank1BB | Rank2BB | Rank3BB | Rank4BB | Rank5BB; + const Bitboard BlackCamp = Rank8BB | Rank7BB | Rank6BB | Rank5BB | Rank4BB; + const Bitboard QueenSide = FileABB | FileBBB | FileCBB | FileDBB; + const Bitboard CenterFiles = FileCBB | FileDBB | FileEBB | FileFBB; + const Bitboard KingSide = FileEBB | FileFBB | FileGBB | FileHBB; + + const Bitboard KingFlank[COLOR_NB][FILE_NB] = { + { QueenSide & WhiteCamp, QueenSide & WhiteCamp, QueenSide & WhiteCamp, CenterFiles & WhiteCamp, + CenterFiles & WhiteCamp, KingSide & WhiteCamp, KingSide & WhiteCamp, KingSide & WhiteCamp }, + { QueenSide & BlackCamp, QueenSide & BlackCamp, QueenSide & BlackCamp, CenterFiles & BlackCamp, + CenterFiles & BlackCamp, KingSide & BlackCamp, KingSide & BlackCamp, KingSide & BlackCamp }, + }; + + template Score evaluate_king(const Position& pos, const EvalInfo& ei) { - const Color Them = (Us == WHITE ? BLACK : WHITE); + const Color Them = (Us == WHITE ? BLACK : WHITE); + const Square Up = (Us == WHITE ? DELTA_N : DELTA_S); - Bitboard undefended, b, b1, b2, safe; + Bitboard undefended, b, b1, b2, safe, other; int attackUnits; - const Square ksq = pos.king_square(Us); + const Square ksq = pos.square(Us); // King shelter and enemy pawns storm Score score = ei.pi->king_safety(pos, ksq); @@ -439,138 +409,184 @@ namespace { // Main king safety evaluation if (ei.kingAttackersCount[Them]) { - // Find the attacked squares around the king which have no defenders - // apart from the king itself - undefended = ei.attackedBy[Them][ALL_PIECES] - & ei.attackedBy[Us][KING] - & ~( ei.attackedBy[Us][PAWN] | ei.attackedBy[Us][KNIGHT] - | ei.attackedBy[Us][BISHOP] | ei.attackedBy[Us][ROOK] - | ei.attackedBy[Us][QUEEN]); + // Find the attacked squares which are defended only by the king... + undefended = ei.attackedBy[Them][ALL_PIECES] + & ei.attackedBy[Us][KING] + & ~ei.attackedBy2[Us]; + + // ... and those which are not defended at all in the larger king ring + b = ei.attackedBy[Them][ALL_PIECES] & ~ei.attackedBy[Us][ALL_PIECES] + & ei.kingRing[Us] & ~pos.pieces(Them); // Initialize the 'attackUnits' variable, which is used later on as an - // index 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)) - + 2 * (ei.pinnedPieces[Us] != 0) - - mg_value(score) / 32; + attackUnits = std::min(72, ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them]) + + 9 * ei.kingAdjacentZoneAttacksCount[Them] + + 21 * popcount(undefended) + + 12 * (popcount(b) + !!ei.pinnedPieces[Us]) + - 64 * !pos.count(Them) + - mg_value(score) / 8; // Analyse the enemy's safe queen contact checks. Firstly, find the - // undefended squares around the king 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]); - - if (b) - attackUnits += QueenContactCheck - * popcount(b) - * (Them == pos.side_to_move() ? 2 : 1); - } - - // 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's rook gives check - b &= PseudoAttacks[ROOK][ksq]; + // ...and keep squares supported by another enemy piece + attackUnits += QueenContactCheck * popcount(b & ei.attackedBy2[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][QUEEN]); - - if (b) - attackUnits += RookContactCheck - * popcount(b) - * (Them == pos.side_to_move() ? 2 : 1); - } + // Analyse the safe enemy's checks which are possible on next move... + safe = ~(ei.attackedBy[Us][ALL_PIECES] | pos.pieces(Them)); - // Analyse the enemy's safe distance checks for sliders and knights - safe = ~(pos.pieces(Them) | ei.attackedBy[Us][ALL_PIECES]); + // ... and some other potential checks, only requiring the square to be + // safe from pawn-attacks, and not being occupied by a blocked pawn. + other = ~( ei.attackedBy[Us][PAWN] + | (pos.pieces(Them, PAWN) & shift_bb(pos.pieces(PAWN)))); - b1 = pos.attacks_from(ksq) & safe; - b2 = pos.attacks_from(ksq) & safe; + b1 = pos.attacks_from(ksq); + b2 = pos.attacks_from(ksq); // Enemy queen safe checks - b = (b1 | b2) & ei.attackedBy[Them][QUEEN]; - if (b) - attackUnits += QueenCheck * popcount(b); + if ((b1 | b2) & ei.attackedBy[Them][QUEEN] & safe) + attackUnits += QueenCheck, score -= SafeCheck; - // Enemy rooks safe checks - b = b1 & ei.attackedBy[Them][ROOK]; - if (b) - attackUnits += RookCheck * popcount(b); + // For other pieces, also consider the square safe if attacked twice, + // and only defended by a queen. + safe |= ei.attackedBy2[Them] + & ~(ei.attackedBy2[Us] | pos.pieces(Them)) + & ei.attackedBy[Us][QUEEN]; - // Enemy bishops safe checks - b = b2 & ei.attackedBy[Them][BISHOP]; - if (b) - attackUnits += BishopCheck * popcount(b); + // Enemy rooks safe and other checks + if (b1 & ei.attackedBy[Them][ROOK] & safe) + attackUnits += RookCheck, score -= SafeCheck; - // Enemy knights safe checks - b = pos.attacks_from(ksq) & ei.attackedBy[Them][KNIGHT] & safe; - if (b) - attackUnits += KnightCheck * popcount(b); + else if (b1 & ei.attackedBy[Them][ROOK] & other) + score -= OtherCheck; + + // Enemy bishops safe and other checks + if (b2 & ei.attackedBy[Them][BISHOP] & safe) + attackUnits += BishopCheck, score -= SafeCheck; + + else if (b2 & ei.attackedBy[Them][BISHOP] & other) + score -= OtherCheck; - // To index KingDanger[] attackUnits must be in [0, 99] range - attackUnits = std::min(99, std::max(0, attackUnits)); + // Enemy knights safe and other checks + b = pos.attacks_from(ksq) & ei.attackedBy[Them][KNIGHT]; + if (b & safe) + attackUnits += KnightCheck, score -= SafeCheck; + + else if (b & other) + score -= OtherCheck; // Finally, extract the king danger score from the KingDanger[] - // array and subtract the score from evaluation. - score -= KingDanger[Us == Search::RootColor][attackUnits]; + // array and subtract the score from the evaluation. + score -= KingDanger[std::max(std::min(attackUnits, 399), 0)]; } - if (Trace) - Tracing::terms[Us][KING] = score; + // King tropism: firstly, find squares that opponent attacks in our king flank + b = ei.attackedBy[Them][ALL_PIECES] & KingFlank[Us][file_of(ksq)]; + + assert(((Us == WHITE ? b << 4 : b >> 4) & b) == 0); + assert(popcount(Us == WHITE ? b << 4 : b >> 4) == popcount(b)); + + // Secondly, add the squares which are attacked twice in that flank and + // which are not defended by our pawns. + b = (Us == WHITE ? b << 4 : b >> 4) + | (b & ei.attackedBy2[Them] & ~ei.attackedBy[Us][PAWN]); + + score -= CloseEnemies * popcount(b); + + if (DoTrace) + Trace::add(KING, Us, score); return score; } - // evaluate_threats() assigns bonuses according to the type of attacking piece - // and the type of attacked one. + // evaluate_threats() assigns bonuses according to the types of the attacking + // and the attacked pieces. - template + 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 { Minor, Rook }; + + Bitboard b, weak, defended, safeThreats; 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]; + // Small bonus if the opponent has loose pawns or pieces + if ( (pos.pieces(Them) ^ pos.pieces(Them, QUEEN, KING)) + & ~(ei.attackedBy[Us][ALL_PIECES] | ei.attackedBy[Them][ALL_PIECES])) + score += LooseEnemies; + + // Non-pawn enemies attacked by a pawn + weak = (pos.pieces(Them) ^ pos.pieces(Them, PAWN)) & ei.attackedBy[Us][PAWN]; - if (undefendedMinors) - score += UndefendedMinor; + if (weak) + { + b = pos.pieces(Us, PAWN) & ( ~ei.attackedBy[Them][ALL_PIECES] + | ei.attackedBy[Us][ALL_PIECES]); - // Enemy pieces not defended by a pawn and under our attack - weakEnemies = pos.pieces(Them) - & ~ei.attackedBy[Them][PAWN] - & ei.attackedBy[Us][ALL_PIECES]; + safeThreats = (shift_bb(b) | shift_bb(b)) & weak; - // Add a bonus according if the attacking pieces are minor or major - if (weakEnemies) + if (weak ^ safeThreats) + score += ThreatByHangingPawn; + + while (safeThreats) + score += ThreatBySafePawn[type_of(pos.piece_on(pop_lsb(&safeThreats)))]; + } + + // Non-pawn enemies defended by a pawn + defended = (pos.pieces(Them) ^ pos.pieces(Them, PAWN)) & ei.attackedBy[Them][PAWN]; + + // 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 to the kind of attacking pieces + if (defended | weak) { - b = weakEnemies & (ei.attackedBy[Us][KNIGHT] | ei.attackedBy[Us][BISHOP]); - if (b) - score += Threat[0][type_of(pos.piece_on(lsb(b)))]; + b = (defended | weak) & (ei.attackedBy[Us][KNIGHT] | ei.attackedBy[Us][BISHOP]); + while (b) + score += Threat[Minor][type_of(pos.piece_on(pop_lsb(&b)))]; - b = weakEnemies & (ei.attackedBy[Us][ROOK] | ei.attackedBy[Us][QUEEN]); + b = (pos.pieces(Them, QUEEN) | weak) & ei.attackedBy[Us][ROOK]; + while (b) + score += Threat[Rook ][type_of(pos.piece_on(pop_lsb(&b)))]; + + score += Hanging * popcount(weak & ~ei.attackedBy[Them][ALL_PIECES]); + + b = weak & ei.attackedBy[Us][KING]; if (b) - score += Threat[1][type_of(pos.piece_on(lsb(b)))]; + score += ThreatByKing[more_than_one(b)]; } - if (Trace) - Tracing::terms[Us][Tracing::THREAT] = score; + // Bonus if some pawns can safely push and attack an enemy piece + b = pos.pieces(Us, PAWN) & ~TRank7BB; + b = shift_bb(b | (shift_bb(b & TRank2BB) & ~pos.pieces())); + + b &= ~pos.pieces() + & ~ei.attackedBy[Them][PAWN] + & (ei.attackedBy[Us][ALL_PIECES] | ~ei.attackedBy[Them][ALL_PIECES]); + + b = (shift_bb(b) | shift_bb(b)) + & pos.pieces(Them) + & ~ei.attackedBy[Us][PAWN]; + + score += ThreatByPawnPush * popcount(b); + + if (DoTrace) + Trace::add(THREAT, Us, score); return score; } @@ -578,12 +594,12 @@ namespace { // evaluate_passed_pawns() evaluates the passed pawns of the given color - template + template 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); @@ -593,114 +609,67 @@ namespace { Square s = pop_lsb(&b); assert(pos.pawn_passed(Us, s)); + assert(!(pos.pieces(PAWN) & forward_bb(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 = Passed[MG][r], ebonus = Passed[EG][r]; 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.square(Them), blockSq) * 5 * rr + - distance(pos.square(Us ), blockSq) * 2 * rr; // If blockSq is not the queening square then consider also a second push if (relative_rank(Us, blockSq) != RANK_8) - ebonus -= Value(rr * square_distance(pos.king_square(Us), blockSq + pawn_push(Us))); + ebonus -= distance(pos.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 ? 18 : !(unsafeSquares & blockSq) ? 8 : 0; + + // If the path to the queen is fully defended, assign a big bonus. + // Otherwise assign a smaller bonus if the block square is defended. 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 + r * 2, 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; - - score += make_score(mbonus, ebonus); + score += make_score(mbonus, ebonus) + PassedFile[file_of(s)]; } - if (Trace) - Tracing::terms[Us][Tracing::PASSED] = apply_weight(score, Weights[PassedPawns]); + if (DoTrace) + Trace::add(PASSED, Us, score); // 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))); + return score; } @@ -708,17 +677,20 @@ namespace { // 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); + const Bitboard SpaceMask = + Us == WHITE ? (FileCBB | FileDBB | FileEBB | FileFBB) & (Rank2BB | Rank3BB | Rank4BB) + : (FileCBB | FileDBB | FileEBB | FileFBB) & (Rank7BB | Rank6BB | Rank5BB); // Find the safe squares for our pieces inside the area defined by - // SpaceMask[]. A square is unsafe if it is attacked by an enemy + // SpaceMask. A square is unsafe if it is attacked by an enemy // pawn, or if it is undefended and attacked by an enemy piece. - Bitboard safe = SpaceMask[Us] + Bitboard safe = SpaceMask & ~pos.pieces(Us, PAWN) & ~ei.attackedBy[Them][PAWN] & (ei.attackedBy[Us][ALL_PIECES] | ~ei.attackedBy[Them][ALL_PIECES]); @@ -728,241 +700,239 @@ namespace { behind |= (Us == WHITE ? behind >> 8 : behind << 8); behind |= (Us == WHITE ? behind >> 16 : behind << 16); - // Since SpaceMask[Us] is fully on our half of the board + // Since SpaceMask[Us] is fully on our half of the board... assert(unsigned(safe >> (Us == WHITE ? 32 : 0)) == 0); - // Count safe + (behind & safe) with a single popcount - return popcount((Us == WHITE ? safe << 32 : safe >> 32) | (behind & safe)); + // ...count safe + (behind & safe) with a single popcount + int bonus = popcount((Us == WHITE ? safe << 32 : safe >> 32) | (behind & safe)); + bonus = std::min(16, bonus); + int weight = pos.count(Us); + + return make_score(bonus * weight * weight / 22, 0); } - // do_evaluate() is the evaluation entry point, called directly from evaluate() + // evaluate_initiative() computes the initiative correction value for the + // position, i.e., second order bonus/malus based on the known attacking/defending + // status of the players. + Score evaluate_initiative(const Position& pos, int asymmetry, Value eg) { - template - Value do_evaluate(const Position& pos) { + int kingDistance = distance(pos.square(WHITE), pos.square(BLACK)) + - distance(pos.square(WHITE), pos.square(BLACK)); + int pawns = pos.count(WHITE) + pos.count(BLACK); - assert(!pos.checkers()); + // Compute the initiative bonus for the attacking side + int initiative = 8 * (asymmetry + kingDistance - 15) + 12 * pawns; - EvalInfo ei; - Score score, mobility[2] = { SCORE_ZERO, SCORE_ZERO }; - Thread* thisThread = pos.this_thread(); + // Now apply the bonus: note that we find the attacking side by extracting + // the sign of the endgame value, and that we carefully cap the bonus so + // that the endgame score will never be divided by more than two. + int value = ((eg > 0) - (eg < 0)) * std::max(initiative, -abs(eg / 2)); - // 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); + return make_score(0, value); + } - // 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); + // evaluate_scale_factor() computes the scale factor for the winning side + ScaleFactor evaluate_scale_factor(const Position& pos, const EvalInfo& ei, Value eg) { - // Probe the pawn hash table - ei.pi = Pawns::probe(pos, thisThread->pawnsTable); - score += apply_weight(ei.pi->pawns_value(), Weights[PawnStructure]); + Color strongSide = eg > VALUE_DRAW ? WHITE : BLACK; + ScaleFactor sf = ei.me->scale_factor(pos, strongSide); - // Initialize attack and king safety bitboards - init_eval_info(pos, ei); - init_eval_info(pos, ei); + // If we don't already have an unusual scale factor, check for certain + // types of endgames, and use a lower scale for those. + if ( ei.me->game_phase() < PHASE_MIDGAME + && (sf == SCALE_FACTOR_NORMAL || sf == SCALE_FACTOR_ONEPAWN)) + { + if (pos.opposite_bishops()) + { + // Endgame with opposite-colored bishops and no other pieces (ignoring pawns) + // is almost a draw, in case of KBP vs KB, it is even more a draw. + if ( pos.non_pawn_material(WHITE) == BishopValueMg + && pos.non_pawn_material(BLACK) == BishopValueMg) + sf = more_than_one(pos.pieces(PAWN)) ? ScaleFactor(31) : ScaleFactor(9); - ei.attackedBy[WHITE][ALL_PIECES] |= ei.attackedBy[WHITE][KING]; - ei.attackedBy[BLACK][ALL_PIECES] |= ei.attackedBy[BLACK][KING]; + // Endgame with opposite-colored bishops, but also other pieces. Still + // a bit drawish, but not as drawish as with only the two bishops. + else + sf = ScaleFactor(46); + } + // Endings where weaker side can place his king in front of the opponent's + // pawns are drawish. + else if ( abs(eg) <= BishopValueEg + && pos.count(strongSide) <= 2 + && !pos.pawn_passed(~strongSide, pos.square(~strongSide))) + sf = ScaleFactor(37 + 7 * pos.count(strongSide)); + } - // Do not include in mobility squares protected by enemy pawns or occupied by our pieces - Bitboard mobilityArea[] = { ~(ei.attackedBy[BLACK][PAWN] | pos.pieces(WHITE, PAWN, KING)), - ~(ei.attackedBy[WHITE][PAWN] | pos.pieces(BLACK, PAWN, KING)) }; + return sf; + } - // Evaluate pieces and mobility - score += evaluate_pieces(pos, ei, mobility, mobilityArea); - score += apply_weight(mobility[WHITE] - mobility[BLACK], Weights[Mobility]); +} // namespace - // 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() is the main evaluation function. It returns a static evaluation +/// of the position from the point of view of the side to move. - // Evaluate passed pawns, we need full attack information including king - score += evaluate_passed_pawns(pos, ei) - - evaluate_passed_pawns(pos, ei); +template +Value Eval::evaluate(const Position& pos) { - // 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); + assert(!pos.checkers()); - // 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]); - } + EvalInfo ei; + Score score, mobility[COLOR_NB] = { SCORE_ZERO, SCORE_ZERO }; - // 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); + // Initialize score by reading the incrementally updated scores included in + // the position object (material + piece square tables). Score is computed + // internally from the white point of view. + score = pos.psq_score(); - // 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); - } + // Probe the material hash table + ei.me = Material::probe(pos); + score += ei.me->imbalance(); - Value v = interpolate(score, ei.mi->game_phase(), sf); + // If we have a specialized evaluation function for the current material + // configuration, call it and return. + if (ei.me->specialized_eval_exists()) + return ei.me->evaluate(pos); - // 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()); - 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; - } + // Probe the pawn hash table + ei.pi = Pawns::probe(pos); + score += ei.pi->pawns_score(); - return pos.side_to_move() == WHITE ? v : -v; - } + // Initialize attack and king safety bitboards + ei.attackedBy[WHITE][ALL_PIECES] = ei.attackedBy[BLACK][ALL_PIECES] = 0; + ei.attackedBy[WHITE][KING] = pos.attacks_from(pos.square(WHITE)); + ei.attackedBy[BLACK][KING] = pos.attacks_from(pos.square(BLACK)); + eval_init(pos, ei); + eval_init(pos, ei); + // Pawns blocked or on ranks 2 and 3 will be excluded from the mobility area + Bitboard blockedPawns[] = { + pos.pieces(WHITE, PAWN) & (shift_bb(pos.pieces()) | Rank2BB | Rank3BB), + pos.pieces(BLACK, PAWN) & (shift_bb(pos.pieces()) | Rank7BB | Rank6BB) + }; - // Tracing function definitions + // Do not include in mobility area squares protected by enemy pawns, or occupied + // by our blocked pawns or king. + Bitboard mobilityArea[] = { + ~(ei.attackedBy[BLACK][PAWN] | blockedPawns[WHITE] | pos.square(WHITE)), + ~(ei.attackedBy[WHITE][PAWN] | blockedPawns[BLACK] | pos.square(BLACK)) + }; - double Tracing::to_cp(Value v) { return double(v) / PawnValueEg; } + // Evaluate all pieces but king and pawns + score += evaluate_pieces(pos, ei, mobility, mobilityArea); + score += mobility[WHITE] - mobility[BLACK]; - void Tracing::add_term(int idx, Score wScore, Score bScore) { + // Evaluate kings after all other pieces because we need full attack + // information when computing the king safety evaluation. + score += evaluate_king(pos, ei) + - evaluate_king(pos, ei); - terms[WHITE][idx] = wScore; - terms[BLACK][idx] = bScore; - } + // Evaluate tactical threats, we need full attack information including king + score += evaluate_threats(pos, ei) + - evaluate_threats(pos, ei); - void Tracing::format_row(std::stringstream& ss, const char* name, int idx) { - - Score wScore = terms[WHITE][idx]; - Score bScore = terms[BLACK][idx]; - - switch (idx) { - case PST: case IMBALANCE: case PAWN: case TOTAL: - ss << std::setw(20) << 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 - << 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"; - } - } + // Evaluate passed pawns, we need full attack information including king + score += evaluate_passed_pawns(pos, ei) + - evaluate_passed_pawns(pos, ei); - std::string Tracing::do_trace(const Position& pos) { + // If both sides have only pawns, score for potential unstoppable pawns + if (!pos.non_pawn_material(WHITE) && !pos.non_pawn_material(BLACK)) + { + Bitboard b; + if ((b = ei.pi->passed_pawns(WHITE)) != 0) + score += Unstoppable * int(relative_rank(WHITE, frontmost_sq(WHITE, b))); - std::memset(terms, 0, sizeof(terms)); + if ((b = ei.pi->passed_pawns(BLACK)) != 0) + score -= Unstoppable * int(relative_rank(BLACK, frontmost_sq(BLACK, b))); + } - Value v = do_evaluate(pos); - v = pos.side_to_move() == WHITE ? v : -v; // White's point of view + // Evaluate space for both sides, only during opening + if (pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK) >= 12222) + score += evaluate_space(pos, ei) + - evaluate_space(pos, ei); - 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"; + // Evaluate position potential for the winning side + score += evaluate_initiative(pos, ei.pi->pawn_asymmetry(), eg_value(score)); - 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); + // Evaluate scale factor for the winning side + ScaleFactor sf = evaluate_scale_factor(pos, ei, eg_value(score)); - ss << "---------------------+-------------+-------------+-------------\n"; - format_row(ss, "Total", TOTAL); + // Interpolate between a middlegame and a (scaled by 'sf') endgame score + Value v = mg_value(score) * int(ei.me->game_phase()) + + eg_value(score) * int(PHASE_MIDGAME - ei.me->game_phase()) * sf / SCALE_FACTOR_NORMAL; - ss << "\nTotal Evaluation: " << to_cp(v) << " (white side)\n"; + v /= int(PHASE_MIDGAME); - return ss.str(); + // In case of tracing add all remaining individual evaluation terms + if (DoTrace) + { + Trace::add(MATERIAL, pos.psq_score()); + Trace::add(IMBALANCE, ei.me->imbalance()); + Trace::add(PAWN, ei.pi->pawns_score()); + Trace::add(MOBILITY, mobility[WHITE], mobility[BLACK]); + Trace::add(SPACE, evaluate_space(pos, ei) + , evaluate_space(pos, ei)); + Trace::add(TOTAL, score); } -} // namespace + return (pos.side_to_move() == WHITE ? v : -v) + Eval::Tempo; // Side to move point of view +} +// Explicit template instantiations +template Value Eval::evaluate(const Position&); +template Value Eval::evaluate(const Position&); -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. +/// 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. Useful for debugging. - Value evaluate(const Position& pos) { - return do_evaluate(pos); - } +std::string Eval::trace(const Position& pos) { + std::memset(scores, 0, sizeof(scores)); - /// 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); - } + Value v = evaluate(pos); + v = pos.side_to_move() == WHITE ? v : -v; // White's point of view + std::stringstream ss; + ss << std::showpoint << std::noshowpos << std::fixed << std::setprecision(2) + << " Eval term | White | Black | Total \n" + << " | MG EG | MG EG | MG EG \n" + << "----------------+-------------+-------------+-------------\n" + << " Material | " << Term(MATERIAL) + << " Imbalance | " << Term(IMBALANCE) + << " Pawns | " << Term(PAWN) + << " Knights | " << Term(KNIGHT) + << " Bishop | " << Term(BISHOP) + << " Rooks | " << Term(ROOK) + << " Queens | " << Term(QUEEN) + << " Mobility | " << Term(MOBILITY) + << " King safety | " << Term(KING) + << " Threats | " << Term(THREAT) + << " Passed pawns | " << Term(PASSED) + << " Space | " << Term(SPACE) + << "----------------+-------------+-------------+-------------\n" + << " Total | " << Term(TOTAL); - /// init() computes evaluation weights from the corresponding UCI parameters - /// and setup king tables. + ss << "\nTotal Evaluation: " << to_cp(v) << " (white side)\n"; - void init() { + return ss.str(); +} - 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; +/// init() computes evaluation weights, usually at startup - for (int t = 0, i = 1; i < 100; ++i) - { - t = std::min(Peak, std::min(int(0.4 * i * i), t + MaxSlope)); +void Eval::init() { - KingDanger[1][i] = apply_weight(make_score(t, 0), Weights[KingDangerUs]); - KingDanger[0][i] = apply_weight(make_score(t, 0), Weights[KingDangerThem]); - } - } + const int MaxSlope = 322; + const int Peak = 47410; + int t = 0; -} // namespace Eval + for (int i = 0; i < 400; ++i) + { + t = std::min(Peak, std::min(i * i - 16, t + MaxSlope)); + KingDanger[i] = make_score(t * 268 / 7700, 0); + } +}