X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fevaluate.cpp;h=47d5eb3e9bc93760432f369c04195afff4f20ac3;hp=9007e9c78a1d73e642e89e2ee07c90487fbc7f30;hb=a56322fde813094afd8ffa60d12761f94e0bd3ef;hpb=2655f93c322c69c9ad85bd4be69d545c05e9260a diff --git a/src/evaluate.cpp b/src/evaluate.cpp index 9007e9c7..6e515d88 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) 2008-2009 Marco Costalba + Copyright (C) 2008-2012 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 @@ -17,40 +17,69 @@ along with this program. If not, see . */ - -//// -//// Includes -//// - #include -#include +#include +#include +#include #include "bitcount.h" #include "evaluate.h" #include "material.h" #include "pawns.h" -#include "scale.h" #include "thread.h" #include "ucioption.h" - -//// -//// Local definitions -//// - namespace { - const int Sign[2] = { 1, -1 }; + // Struct EvalInfo contains various information computed and collected + // by the evaluation functions. + struct EvalInfo { + + // Pointers to material and pawn hash table entries + MaterialInfo* mi; + PawnInfo* pi; + + // attackedBy[color][piece type] is a bitboard representing all squares + // attacked by a given color and piece type, attackedBy[color][0] contains + // all squares attacked by the given color. + Bitboard attackedBy[2][8]; + + // kingRing[color] is the zone around the king which is considered + // by the king safety evaluation. This consists of the squares directly + // adjacent to the king, and the three (or two, for a king on an edge file) + // squares two ranks in front of the king. For instance, if black's king + // is on g8, kingRing[BLACK] is a bitboard containing the squares f8, h8, + // f7, g7, h7, f6, g6 and h6. + Bitboard kingRing[2]; + + // kingAttackersCount[color] is the number of pieces of the given color + // which attack a square in the kingRing of the enemy king. + int kingAttackersCount[2]; + + // kingAttackersWeight[color] is the sum of the "weight" of the pieces of the + // given color which attack a square in the kingRing of the enemy king. The + // weights of the individual piece types are given by the variables + // QueenAttackWeight, RookAttackWeight, BishopAttackWeight and + // KnightAttackWeight in evaluate.cpp + int kingAttackersWeight[2]; + + // 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]. + int kingAdjacentZoneAttacksCount[2]; + }; // Evaluation grain size, must be a power of 2 const int GrainSize = 8; // Evaluation weights, initialized from UCI options - int WeightMobilityMidgame, WeightMobilityEndgame; - int WeightPawnStructureMidgame, WeightPawnStructureEndgame; - int WeightPassedPawnsMidgame, WeightPassedPawnsEndgame; - int WeightKingSafety[2]; - int WeightSpace; + enum { Mobility, PassedPawns, Space, KingDangerUs, KingDangerThem }; + Score Weights[6]; + + typedef Value V; + #define S(mg, eg) make_score(mg, eg) // Internal evaluation weights. These are applied on top of the evaluation // weights read from UCI parameters. The purpose is to be able to change @@ -58,192 +87,121 @@ namespace { // parameters at 100, which looks prettier. // // Values modified by Joona Kiiski - const int WeightMobilityMidgameInternal = 248; - const int WeightMobilityEndgameInternal = 271; - const int WeightPawnStructureMidgameInternal = 233; - const int WeightPawnStructureEndgameInternal = 201; - const int WeightPassedPawnsMidgameInternal = 252; - const int WeightPassedPawnsEndgameInternal = 259; - const int WeightKingSafetyInternal = 247; - const int WeightKingOppSafetyInternal = 259; - const int WeightSpaceInternal = 46; - - // Mobility and outposts bonus modified by Joona Kiiski - // - // Visually better to define tables constants - typedef Value V; - - // Knight mobility bonus in middle game and endgame, indexed by the number - // of attacked squares not occupied by friendly piecess. - const Value MidgameKnightMobilityBonus[] = { - // 0 1 2 3 4 5 6 7 8 - V(-38), V(-25),V(-12), V(0), V(12), V(25), V(31), V(38), V(38) - }; - - const Value EndgameKnightMobilityBonus[] = { - // 0 1 2 3 4 5 6 7 8 - V(-33), V(-23),V(-13), V(-3), V(7), V(17), V(22), V(27), V(27) - }; - - // Bishop mobility bonus in middle game and endgame, indexed by the number - // of attacked squares not occupied by friendly pieces. X-ray attacks through - // queens are also included. - const Value MidgameBishopMobilityBonus[] = { - // 0 1 2 3 4 5 6 7 - V(-25), V(-11), V(3), V(17), V(31), V(45), V(57), V(65), - // 8 9 10 11 12 13 14 15 - V( 71), V( 74), V(76), V(78), V(79), V(80), V(81), V(81) - }; - - const Value EndgameBishopMobilityBonus[] = { - // 0 1 2 3 4 5 6 7 - V(-30), V(-16), V(-2), V(12), V(26), V(40), V(52), V(60), - // 8 9 10 11 12 13 14 15 - V( 65), V( 69), V(71), V(73), V(74), V(75), V(76), V(76) + const Score WeightsInternal[] = { + S(252, 344), S(216, 266), S(46, 0), S(247, 0), S(259, 0) }; - // Rook mobility bonus in middle game and endgame, indexed by the number - // of attacked squares not occupied by friendly pieces. X-ray attacks through - // queens and rooks are also included. - const Value MidgameRookMobilityBonus[] = { - // 0 1 2 3 4 5 6 7 - V(-20), V(-14), V(-8), V(-2), V(4), V(10), V(14), V(19), - // 8 9 10 11 12 13 14 15 - V( 23), V( 26), V(27), V(28), V(29), V(30), V(31), V(32) + // MobilityBonus[PieceType][attacked] contains mobility 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(-38,-33), S(-25,-23), S(-12,-13), S( 0, -3), S(12, 7), S(25, 17), // Knights + S( 31, 22), S( 38, 27), S( 38, 27) }, + { S(-25,-30), S(-11,-16), S( 3, -2), S(17, 12), S(31, 26), S(45, 40), // Bishops + S( 57, 52), S( 65, 60), S( 71, 65), S(74, 69), S(76, 71), S(78, 73), + S( 79, 74), S( 80, 75), S( 81, 76), S(81, 76) }, + { S(-20,-36), S(-14,-19), S( -8, -3), S(-2, 13), S( 4, 29), S(10, 46), // Rooks + S( 14, 62), S( 19, 79), S( 23, 95), S(26,106), S(27,111), S(28,114), + S( 29,116), S( 30,117), S( 31,118), S(32,118) }, + { S(-10,-18), S( -8,-13), S( -6, -7), S(-3, -2), S(-1, 3), S( 1, 8), // Queens + S( 3, 13), S( 5, 19), S( 8, 23), S(10, 27), S(12, 32), S(15, 34), + S( 16, 35), S( 17, 35), S( 18, 35), S(20, 35), S(20, 35), S(20, 35), + S( 20, 35), S( 20, 35), S( 20, 35), S(20, 35), S(20, 35), S(20, 35), + S( 20, 35), S( 20, 35), S( 20, 35), S(20, 35), S(20, 35), S(20, 35), + S( 20, 35), S( 20, 35) } }; - const Value EndgameRookMobilityBonus[] = { - // 0 1 2 3 4 5 6 7 - V(-36), V(-19), V(-3), V(13), V(29), V(46), V(62), V(79), - // 8 9 10 11 12 13 14 15 - V( 95), V(106),V(111),V(114),V(116),V(117),V(118),V(118) - }; - - // Queen mobility bonus in middle game and endgame, indexed by the number - // of attacked squares not occupied by friendly pieces. - const Value MidgameQueenMobilityBonus[] = { - // 0 1 2 3 4 5 6 7 - V(-10), V(-8), V(-6), V(-3), V(-1), V( 1), V( 3), V( 5), - // 8 9 10 11 12 13 14 15 - V( 8), V(10), V(12), V(15), V(16), V(17), V(18), V(20), - // 16 17 18 19 20 21 22 23 - V( 20), V(20), V(20), V(20), V(20), V(20), V(20), V(20), - // 24 25 26 27 28 29 30 31 - V( 20), V(20), V(20), V(20), V(20), V(20), V(20), V(20) - }; - - const Value EndgameQueenMobilityBonus[] = { - // 0 1 2 3 4 5 6 7 - V(-18),V(-13), V(-7), V(-2), V( 3), V (8), V(13), V(19), - // 8 9 10 11 12 13 14 15 - V( 23), V(27), V(32), V(34), V(35), V(35), V(35), V(35), - // 16 17 18 19 20 21 22 23 - V( 35), V(35), V(35), V(35), V(35), V(35), V(35), V(35), - // 24 25 26 27 28 29 30 31 - V( 35), V(35), V(35), V(35), V(35), V(35), V(35), V(35) + // OutpostBonus[PieceType][Square] contains outpost bonuses of knights and + // bishops, indexed by piece type and square (from white's point of view). + const Value OutpostBonus[][64] = { + { + // 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 bonuses for knights and bishops, indexed by square (from white's - // point of view). - const Value KnightOutpostBonus[64] = { - // A B C D E F G H - V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // 1 - V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // 2 - V(0), V(0), V(4), V(8), V(8), V(4), V(0), V(0), // 3 - V(0), V(4),V(17),V(26),V(26),V(17), V(4), V(0), // 4 - V(0), V(8),V(26),V(35),V(35),V(26), V(8), V(0), // 5 - V(0), V(4),V(17),V(17),V(17),V(17), V(4), V(0), // 6 - V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // 7 - V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0) // 8 + // ThreatBonus[attacking][attacked] contains threat bonuses according to + // which piece type attacks which one. + const Score ThreatBonus[][8] = { + {}, {}, + { 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(-1, 29), 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 }; - const Value BishopOutpostBonus[64] = { - // A B C D E F G H - V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // 1 - V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // 2 - V(0), V(0), V(5), V(5), V(5), V(5), V(0), V(0), // 3 - V(0), V(5),V(10),V(10),V(10),V(10), V(5), V(0), // 4 - V(0),V(10),V(21),V(21),V(21),V(21),V(10), V(0), // 5 - V(0), V(5), V(8), V(8), V(8), V(8), V(5), V(0), // 6 - V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // 7 - V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0) // 8 + // ThreatenedByPawnPenalty[PieceType] contains a penalty according to which + // piece type is attacked by an enemy pawn. + const Score ThreatenedByPawnPenalty[] = { + S(0, 0), S(0, 0), S(56, 70), S(56, 70), S(76, 99), S(86, 118) }; - // Bonus for unstoppable passed pawns - const Value UnstoppablePawnValue = Value(0x500); + #undef S // Rooks and queens on the 7th rank (modified by Joona Kiiski) - const Value MidgameRookOn7thBonus = Value(47); - const Value EndgameRookOn7thBonus = Value(98); - const Value MidgameQueenOn7thBonus = Value(27); - const Value EndgameQueenOn7thBonus = Value(54); + const Score RookOn7thBonus = make_score(47, 98); + const Score QueenOn7thBonus = make_score(27, 54); // Rooks on open files (modified by Joona Kiiski) - const Value RookOpenFileBonus = Value(43); - const Value RookHalfOpenFileBonus = Value(19); + const Score RookOpenFileBonus = make_score(43, 21); + const Score RookHalfOpenFileBonus = make_score(19, 10); // Penalty for rooks trapped inside a friendly king which has lost the // right to castle. const Value TrappedRookPenalty = Value(180); - // Penalty for a bishop on a7/h7 (a2/h2 for black) which is trapped by - // enemy pawns. - const Value TrappedBishopA7H7Penalty = Value(300); - - // Bitboard masks for detecting trapped bishops on a7/h7 (a2/h2 for black) - const Bitboard MaskA7H7[2] = { - ((1ULL << SQ_A7) | (1ULL << SQ_H7)), - ((1ULL << SQ_A2) | (1ULL << SQ_H2)) - }; - // 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 Value TrappedBishopA1H1Penalty = Value(100); + const Score TrappedBishopA1H1Penalty = make_score(100, 100); - // Bitboard masks for detecting trapped bishops on a1/h1 (a8/h8 for black) - const Bitboard MaskA1H1[2] = { - ((1ULL << SQ_A1) | (1ULL << SQ_H1)), - ((1ULL << SQ_A8) | (1ULL << SQ_H8)) - }; + // Penalty for BNR that is not defended by anything + const Score UndefendedPiecePenalty = make_score(25, 10); - // The SpaceMask[color] contains the area of the board which is considered + // 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 // based on how many squares inside this area are safe and available for // friendly minor pieces. - const Bitboard SpaceMask[2] = { - (1ULL< - Value do_evaluate(const Position& pos, EvalInfo& ei, int threadID); + template + Value do_evaluate(const Position& pos, Value& margin); - template - void evaluate_pieces_of_color(const Position& pos, EvalInfo& ei); + template + void init_eval_info(const Position& pos, EvalInfo& ei); - template - void evaluate_king(const Position& pos, EvalInfo& ei); + template + Score evaluate_pieces_of_color(const Position& pos, EvalInfo& ei, Score& mobility); - template - void evaluate_space(const Position& pos, EvalInfo& ei); + template + Score evaluate_king(const Position& pos, EvalInfo& ei, Value margins[]); - void evaluate_passed_pawns(const Position& pos, EvalInfo& ei); - void evaluate_trapped_bishop_a7h7(const Position& pos, Square s, Color us, EvalInfo& ei); - void evaluate_trapped_bishop_a1h1(const Position& pos, Square s, Color us, EvalInfo& ei); - inline Value apply_weight(Value v, int w); - Value scale_by_game_phase(Value mv, Value ev, Phase ph, const ScaleFactor sf[]); - int weight_option(const std::string& opt, int weight); - void init_safety(); -} + template + Score evaluate_threats(const Position& pos, EvalInfo& ei); + template + int evaluate_space(const Position& pos, EvalInfo& ei); -//// -//// Functions -//// + template + Score evaluate_passed_pawns(const Position& pos, EvalInfo& ei); -/// 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, EvalInfo& ei, int threadID) { + Score evaluate_unstoppable_pawns(const Position& pos, EvalInfo& ei); - return CpuHasPOPCNT ? do_evaluate(pos, ei, threadID) - : do_evaluate(pos, ei, threadID); + inline Score apply_weight(Score v, Score weight); + Value scale_by_game_phase(const Score& v, Phase ph, ScaleFactor sf); + Score weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight); + double to_cp(Value v); + void trace_add(int idx, Score term_w, Score term_b = SCORE_ZERO); + void trace_row(const char* name, int idx); } -namespace { - -template -Value do_evaluate(const Position& pos, EvalInfo& ei, int threadID) { - assert(pos.is_ok()); - assert(threadID >= 0 && threadID < THREAD_MAX); +namespace Eval { - memset(&ei, 0, sizeof(EvalInfo)); + Color RootColor; - // Initialize by reading the incrementally updated scores included in the - // position object (material + piece square tables) - ei.mgValue = pos.mg_value(); - ei.egValue = pos.eg_value(); + /// 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. - // Probe the material hash table - ei.mi = MaterialTable[threadID]->get_material_info(pos); - ei.mgValue += ei.mi->material_value(); - ei.egValue += ei.mi->material_value(); + Value evaluate(const Position& pos, Value& margin) { + return do_evaluate(pos, margin); + } - // 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); - // After get_material_info() call that modifies them - ScaleFactor factor[2]; - factor[WHITE] = ei.mi->scale_factor(pos, WHITE); - factor[BLACK] = ei.mi->scale_factor(pos, BLACK); + /// init() computes evaluation weights from the corresponding UCI parameters + /// and setup king tables. - // Probe the pawn hash table - ei.pi = PawnTable[threadID]->get_pawn_info(pos); - ei.mgValue += apply_weight(ei.pi->mg_value(), WeightPawnStructureMidgame); - ei.egValue += apply_weight(ei.pi->eg_value(), WeightPawnStructureEndgame); - - // Initialize king attack bitboards and king attack zones for both sides - ei.attackedBy[WHITE][KING] = pos.attacks_from(pos.king_square(WHITE)); - ei.attackedBy[BLACK][KING] = pos.attacks_from(pos.king_square(BLACK)); - ei.kingZone[WHITE] = ei.attackedBy[BLACK][KING] | (ei.attackedBy[BLACK][KING] >> 8); - ei.kingZone[BLACK] = ei.attackedBy[WHITE][KING] | (ei.attackedBy[WHITE][KING] << 8); - - // Initialize pawn attack bitboards for both sides - ei.attackedBy[WHITE][PAWN] = ei.pi->pawn_attacks(WHITE); - ei.attackedBy[BLACK][PAWN] = ei.pi->pawn_attacks(BLACK); - Bitboard b1 = ei.attackedBy[WHITE][PAWN] & ei.attackedBy[BLACK][KING]; - Bitboard b2 = ei.attackedBy[BLACK][PAWN] & ei.attackedBy[WHITE][KING]; - if (b1) - ei.kingAttackersCount[WHITE] = count_1s_max_15(b1)/2; - - if (b2) - ei.kingAttackersCount[BLACK] = count_1s_max_15(b2)/2; - - // Evaluate pieces - evaluate_pieces_of_color(pos, ei); - evaluate_pieces_of_color(pos, ei); - - // Kings. Kings are evaluated after all other pieces for both sides, - // because we need complete attack information for all pieces when computing - // the king safety evaluation. - evaluate_king(pos, ei); - evaluate_king(pos, ei); - - // Evaluate passed pawns. We evaluate passed pawns for both sides at once, - // because we need to know which side promotes first in positions where - // both sides have an unstoppable passed pawn. - if (ei.pi->passed_pawns()) - evaluate_passed_pawns(pos, ei); - - Phase phase = pos.game_phase(); - - // Middle-game specific evaluation terms - if (phase > PHASE_ENDGAME) - { - // Pawn storms in positions with opposite castling. - if ( square_file(pos.king_square(WHITE)) >= FILE_E - && square_file(pos.king_square(BLACK)) <= FILE_D) + void init() { - ei.mgValue += ei.pi->queenside_storm_value(WHITE) - - ei.pi->kingside_storm_value(BLACK); + Weights[Mobility] = weight_option("Mobility (Middle Game)", "Mobility (Endgame)", WeightsInternal[Mobility]); + Weights[PassedPawns] = weight_option("Passed Pawns (Middle Game)", "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]); - else if ( square_file(pos.king_square(WHITE)) <= FILE_D - && square_file(pos.king_square(BLACK)) >= FILE_E) + // King safety is asymmetrical. Our king danger level is weighted by + // "Cowardice" UCI parameter, instead the opponent one by "Aggressiveness". + // If running in analysis mode, make sure we use symmetrical king safety. We + // do this by replacing both Weights[kingDangerUs] and Weights[kingDangerThem] + // by their average. + if (Options["UCI_AnalyseMode"]) + Weights[KingDangerUs] = Weights[KingDangerThem] = (Weights[KingDangerUs] + Weights[KingDangerThem]) / 2; - ei.mgValue += ei.pi->kingside_storm_value(WHITE) - - ei.pi->queenside_storm_value(BLACK); + const int MaxSlope = 30; + const int Peak = 1280; - // Evaluate space for both sides - if (ei.mi->space_weight() > 0) + for (int t = 0, i = 1; i < 100; i++) { - evaluate_space(pos, ei); - evaluate_space(pos, ei); + t = std::min(Peak, std::min(int(0.4 * i * i), t + MaxSlope)); + + KingDangerTable[1][i] = apply_weight(make_score(t, 0), Weights[KingDangerUs]); + KingDangerTable[0][i] = apply_weight(make_score(t, 0), Weights[KingDangerThem]); } } - // Mobility - ei.mgValue += apply_weight(ei.mgMobility, WeightMobilityMidgame); - ei.egValue += apply_weight(ei.egMobility, WeightMobilityEndgame); - - // If we don't already have an unusual scale factor, check for opposite - // colored bishop endgames, and use a lower scale for those - if ( phase < PHASE_MIDGAME - && pos.opposite_colored_bishops() - && ( (factor[WHITE] == SCALE_FACTOR_NORMAL && ei.egValue > Value(0)) - || (factor[BLACK] == SCALE_FACTOR_NORMAL && ei.egValue < Value(0)))) - { - ScaleFactor sf; - // Only the two bishops ? - if ( pos.non_pawn_material(WHITE) == BishopValueMidgame - && pos.non_pawn_material(BLACK) == BishopValueMidgame) - { - // 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.piece_count(WHITE, PAWN) + pos.piece_count(BLACK, PAWN) == 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); + /// 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. - if (factor[WHITE] == SCALE_FACTOR_NORMAL) - factor[WHITE] = sf; - if (factor[BLACK] == SCALE_FACTOR_NORMAL) - factor[BLACK] = sf; - } + std::string trace(const Position& pos) { - // Interpolate between the middle game and the endgame score - Color stm = pos.side_to_move(); + Value margin; + std::string totals; - Value v = Sign[stm] * scale_by_game_phase(ei.mgValue, ei.egValue, phase, factor); + RootColor = pos.side_to_move(); - return (ei.mateThreat[stm] == MOVE_NONE ? v : 8 * QueenValueMidgame - v); -} + TraceStream.str(""); + TraceStream << std::showpoint << std::showpos << std::fixed << std::setprecision(2); + memset(TracedScores, 0, 2 * 16 * sizeof(Score)); -} // namespace + do_evaluate(pos, margin); -/// quick_evaluate() does a very approximate evaluation of the current position. -/// It currently considers only material and piece square table scores. Perhaps -/// we should add scores from the pawn and material hash tables? + totals = TraceStream.str(); + TraceStream.str(""); -Value quick_evaluate(const Position &pos) { + TraceStream << std::setw(21) << "Eval term " << "| White | Black | Total \n" + << " | MG EG | MG EG | MG EG \n" + << "---------------------+-------------+-------------+---------------\n"; - assert(pos.is_ok()); + trace_row("Material, PST, Tempo", PST); + trace_row("Material imbalance", IMBALANCE); + trace_row("Pawns", PAWN); + trace_row("Knights", KNIGHT); + trace_row("Bishops", BISHOP); + trace_row("Rooks", ROOK); + trace_row("Queens", QUEEN); + trace_row("Mobility", MOBILITY); + trace_row("King safety", KING); + trace_row("Threats", THREAT); + trace_row("Passed pawns", PASSED); + trace_row("Unstoppable pawns", UNSTOPPABLE); + trace_row("Space", SPACE); - static const - ScaleFactor sf[2] = {SCALE_FACTOR_NORMAL, SCALE_FACTOR_NORMAL}; + TraceStream << "---------------------+-------------+-------------+---------------\n"; + trace_row("Total", TOTAL); + TraceStream << totals; - Value mgv = pos.mg_value(); - Value egv = pos.eg_value(); - Phase ph = pos.game_phase(); - Color stm = pos.side_to_move(); + return TraceStream.str(); + } - return Sign[stm] * scale_by_game_phase(mgv, egv, ph, sf); -} +} // namespace Eval -/// init_eval() initializes various tables used by the evaluation function +namespace { -void init_eval(int threads) { +template +Value do_evaluate(const Position& pos, Value& margin) { - assert(threads <= THREAD_MAX); + assert(!pos.in_check()); - for (int i = 0; i < THREAD_MAX; i++) - { - if (i >= threads) - { - delete PawnTable[i]; - delete MaterialTable[i]; - PawnTable[i] = NULL; - MaterialTable[i] = NULL; - continue; - } - if (!PawnTable[i]) - PawnTable[i] = new PawnInfoTable(PawnTableSize); - if (!MaterialTable[i]) - MaterialTable[i] = new MaterialInfoTable(MaterialTableSize); - } -} + EvalInfo ei; + Value margins[2]; + Score score, mobilityWhite, mobilityBlack; + // Initialize score by reading the incrementally updated scores included + // in the position object (material + piece square tables). + score = pos.value(); -/// quit_eval() releases heap-allocated memory at program termination + // 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; -void quit_eval() { + // Probe the material hash table + ei.mi = Threads[pos.thread()].materialTable.material_info(pos); + score += ei.mi->material_value(); - for (int i = 0; i < THREAD_MAX; i++) + // If we have a specialized evaluation function for the current material + // configuration, call it and return. + if (ei.mi->specialized_eval_exists()) { - delete PawnTable[i]; - delete MaterialTable[i]; - PawnTable[i] = NULL; - MaterialTable[i] = NULL; + margin = VALUE_ZERO; + return ei.mi->evaluate(pos); } -} + // Probe the pawn hash table + ei.pi = Threads[pos.thread()].pawnTable.pawn_info(pos); + score += ei.pi->pawns_value(); + + // 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]); -/// read_weights() reads evaluation weights from the corresponding UCI parameters + // 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); -void read_weights(Color us) { + // Evaluate tactical threats, we need full attack information including king + score += evaluate_threats(pos, ei) + - evaluate_threats(pos, ei); - Color them = opposite_color(us); + // Evaluate passed pawns, we need full attack information including king + score += evaluate_passed_pawns(pos, ei) + - evaluate_passed_pawns(pos, ei); - WeightMobilityMidgame = weight_option("Mobility (Middle Game)", WeightMobilityMidgameInternal); - WeightMobilityEndgame = weight_option("Mobility (Endgame)", WeightMobilityEndgameInternal); - WeightPawnStructureMidgame = weight_option("Pawn Structure (Middle Game)", WeightPawnStructureMidgameInternal); - WeightPawnStructureEndgame = weight_option("Pawn Structure (Endgame)", WeightPawnStructureEndgameInternal); - WeightPassedPawnsMidgame = weight_option("Passed Pawns (Middle Game)", WeightPassedPawnsMidgameInternal); - WeightPassedPawnsEndgame = weight_option("Passed Pawns (Endgame)", WeightPassedPawnsEndgameInternal); - WeightSpace = weight_option("Space", WeightSpaceInternal); - WeightKingSafety[us] = weight_option("Cowardice", WeightKingSafetyInternal); - WeightKingSafety[them] = weight_option("Aggressiveness", WeightKingOppSafetyInternal); + // 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); - // If running in analysis mode, make sure we use symmetrical king safety. We do this - // by replacing both WeightKingSafety[us] and WeightKingSafety[them] by their average. - if (get_option_value_bool("UCI_AnalyseMode")) + // Evaluate space for both sides, only in middle-game. + if (ei.mi->space_weight()) { - WeightKingSafety[us] = (WeightKingSafety[us] + WeightKingSafety[them]) / 2; - WeightKingSafety[them] = WeightKingSafety[us]; + int s = evaluate_space(pos, ei) - evaluate_space(pos, ei); + score += apply_weight(make_score(s * ei.mi->space_weight(), 0), Weights[Space]); } - init_safety(); -} - -namespace { + // 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); - // evaluate_mobility() computes mobility and attacks for every piece + // 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_colored_bishops() + && sf == SCALE_FACTOR_NORMAL) + { + // Only the two bishops ? + if ( pos.non_pawn_material(WHITE) == BishopValueMidgame + && pos.non_pawn_material(BLACK) == BishopValueMidgame) + { + // 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.piece_count(WHITE, PAWN) + pos.piece_count(BLACK, PAWN) == 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); + } - template - int evaluate_mobility(const Position& pos, Bitboard b, EvalInfo& ei) { + // Interpolate between the middle game and the endgame score + margin = margins[pos.side_to_move()]; + Value v = scale_by_game_phase(score, ei.mi->game_phase(), sf); - const Color Them = (Us == WHITE ? BLACK : WHITE); - static const int AttackWeight[] = { 0, 0, KnightAttackWeight, BishopAttackWeight, RookAttackWeight, QueenAttackWeight }; - static const Value* MgBonus[] = { 0, 0, MidgameKnightMobilityBonus, MidgameBishopMobilityBonus, MidgameRookMobilityBonus, MidgameQueenMobilityBonus }; - static const Value* EgBonus[] = { 0, 0, EndgameKnightMobilityBonus, EndgameBishopMobilityBonus, EndgameRookMobilityBonus, EndgameQueenMobilityBonus }; - static const int lastIndex[] = { 0, 0, 8, 15, 15, 31 }; + // In case of tracing add all single evaluation contributions for both white and black + if (Trace) + { + trace_add(PST, pos.value()); + trace_add(IMBALANCE, ei.mi->material_value()); + trace_add(PAWN, ei.pi->pawns_value()); + trace_add(MOBILITY, apply_weight(mobilityWhite, Weights[Mobility]), apply_weight(mobilityBlack, Weights[Mobility])); + trace_add(THREAT, evaluate_threats(pos, ei), evaluate_threats(pos, ei)); + trace_add(PASSED, evaluate_passed_pawns(pos, ei), evaluate_passed_pawns(pos, ei)); + trace_add(UNSTOPPABLE, evaluate_unstoppable_pawns(pos, ei)); + Score w = make_score(ei.mi->space_weight() * evaluate_space(pos, ei), 0); + Score b = make_score(ei.mi->space_weight() * evaluate_space(pos, ei), 0); + trace_add(SPACE, apply_weight(w, Weights[Space]), apply_weight(b, Weights[Space])); + trace_add(TOTAL, score); + TraceStream << "\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); + } - // Update attack info - ei.attackedBy[Us][Piece] |= b; + return pos.side_to_move() == WHITE ? v : -v; +} - // King attacks - if (b & ei.kingZone[Us]) - { - ei.kingAttackersCount[Us]++; - ei.kingAttackersWeight[Us] += AttackWeight[Piece]; - Bitboard bb = (b & ei.attackedBy[Them][KING]); - if (bb) - ei.kingAdjacentZoneAttacksCount[Us] += count_1s_max_15(bb); - } - // Remove squares protected by enemy pawns or occupied by our pieces - b &= ~(ei.attackedBy[Them][PAWN] | pos.pieces_of_color(Us)); + // init_eval_info() initializes king bitboards for given color adding + // pawn attacks. To be done at the beginning of the evaluation. - // The squares occupied by enemy pieces (not defended by pawns) will be - // counted two times instead of one. The shift (almost) guarantees that - // intersection of the shifted value with b is zero so that after or-ing - // the count of 1s bits is increased by the number of affected squares. - b |= Us == WHITE ? ((b & pos.pieces_of_color(Them)) >> 1) - : ((b & pos.pieces_of_color(Them)) << 1); + template + void init_eval_info(const Position& pos, EvalInfo& ei) { - // Mobility - int mob = (Piece != QUEEN ? count_1s_max_15(b) - : count_1s(b)); + const Color Them = (Us == WHITE ? BLACK : WHITE); - if (mob > lastIndex[Piece]) - mob = lastIndex[Piece]; + Bitboard b = ei.attackedBy[Them][KING] = pos.attacks_from(pos.king_square(Them)); + ei.attackedBy[Us][PAWN] = ei.pi->pawn_attacks(Us); - ei.mgMobility += Sign[Us] * MgBonus[Piece][mob]; - ei.egMobility += Sign[Us] * EgBonus[Piece][mob]; - return mob; + // Init king safety tables only if we are going to use them + if ( pos.piece_count(Us, QUEEN) + && pos.non_pawn_material(Us) >= QueenValueMidgame + RookValueMidgame) + { + ei.kingRing[Them] = (b | (Us == WHITE ? b >> 8 : b << 8)); + b &= ei.attackedBy[Us][PAWN]; + ei.kingAttackersCount[Us] = b ? popcount(b) / 2 : 0; + ei.kingAdjacentZoneAttacksCount[Us] = ei.kingAttackersWeight[Us] = 0; + } else + ei.kingRing[Them] = ei.kingAttackersCount[Us] = 0; } // evaluate_outposts() evaluates bishop and knight outposts squares template - void evaluate_outposts(const Position& pos, EvalInfo& ei, Square s) { + Score evaluate_outposts(const Position& pos, EvalInfo& ei, Square s) { const Color Them = (Us == WHITE ? BLACK : WHITE); + assert (Piece == BISHOP || Piece == KNIGHT); + // Initial bonus based on square - Value bonus = (Piece == BISHOP ? BishopOutpostBonus[relative_square(Us, s)] - : KnightOutpostBonus[relative_square(Us, s)]); + Value bonus = OutpostBonus[Piece == 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 - if (bonus && (pos.attacks_from(s, Them) & pos.pieces(PAWN, Us))) + // no minor piece which can exchange the outpost piece. + if (bonus && (ei.attackedBy[Us][PAWN] & s)) { - if ( pos.pieces(KNIGHT, Them) == EmptyBoardBB - && (SquaresByColorBB[square_color(s)] & pos.pieces(BISHOP, Them)) == EmptyBoardBB) + if ( !pos.pieces(KNIGHT, Them) + && !(same_color_squares(s) & pos.pieces(BISHOP, Them))) bonus += bonus + bonus / 2; else bonus += bonus / 2; } - ei.mgValue += Sign[Us] * bonus; - ei.egValue += Sign[Us] * bonus; + return make_score(bonus, bonus); } // evaluate_pieces<>() assigns bonuses and penalties to the pieces of a given color - template - void evaluate_pieces(const Position& pos, EvalInfo& ei) { + template + Score evaluate_pieces(const Position& pos, EvalInfo& ei, Score& mobility, Bitboard mobilityArea) { Bitboard b; Square s, ksq; int mob; File f; + Score score = SCORE_ZERO; const Color Them = (Us == WHITE ? BLACK : WHITE); - const Square* ptr = pos.piece_list_begin(Us, Piece); + const Square* pl = pos.piece_list(Us, Piece); + + ei.attackedBy[Us][Piece] = 0; - while ((s = *ptr++) != SQ_NONE) + while ((s = *pl++) != SQ_NONE) { + // Find attacked squares, including x-ray attacks for bishops and rooks if (Piece == KNIGHT || Piece == QUEEN) b = pos.attacks_from(s); else if (Piece == BISHOP) - b = bishop_attacks_bb(s, pos.occupied_squares() & ~pos.pieces(QUEEN, Us)); + b = attacks_bb(s, pos.pieces() ^ pos.pieces(QUEEN, Us)); else if (Piece == ROOK) - b = rook_attacks_bb(s, pos.occupied_squares() & ~pos.pieces(ROOK, QUEEN, Us)); + b = attacks_bb(s, pos.pieces() ^ pos.pieces(ROOK, QUEEN, Us)); else assert(false); - // Attacks and mobility - mob = evaluate_mobility(pos, b, ei); + ei.attackedBy[Us][Piece] |= b; - // Bishop and knight outposts squares - if ((Piece == BISHOP || Piece == KNIGHT) && pos.square_is_weak(s, Them)) - evaluate_outposts(pos, ei, s); + if (b & ei.kingRing[Them]) + { + ei.kingAttackersCount[Us]++; + ei.kingAttackersWeight[Us] += KingAttackWeights[Piece]; + Bitboard bb = (b & ei.attackedBy[Them][KING]); + if (bb) + ei.kingAdjacentZoneAttacksCount[Us] += popcount(bb); + } + + mob = (Piece != QUEEN ? popcount(b & mobilityArea) + : popcount(b & mobilityArea)); - // Special patterns: trapped bishops on a7/h7/a2/h2 - // and trapped bishops on a1/h1/a8/h8 in Chess960. - if (Piece == BISHOP) + mobility += MobilityBonus[Piece][mob]; + + // Add a bonus if a slider is pinning an enemy piece + if ( (Piece == BISHOP || Piece == ROOK || Piece == QUEEN) + && (PseudoAttacks[Piece][pos.king_square(Them)] & s)) { - if (bit_is_set(MaskA7H7[Us], s)) - evaluate_trapped_bishop_a7h7(pos, s, Us, ei); + b = BetweenBB[s][pos.king_square(Them)] & pos.pieces(); + + assert(b); + + if (single_bit(b) && (b & pos.pieces(Them))) + score += ThreatBonus[Piece][type_of(pos.piece_on(first_1(b)))]; + } - if (Chess960 && bit_is_set(MaskA1H1[Us], s)) - evaluate_trapped_bishop_a1h1(pos, s, Us, ei); + // Decrease score if we are attacked by an enemy pawn. Remaining part + // of threat evaluation must be done later when we have full attack info. + if (ei.attackedBy[Them][PAWN] & s) + score -= ThreatenedByPawnPenalty[Piece]; + + // Bishop and knight outposts squares + if ( (Piece == BISHOP || Piece == KNIGHT) + && !(pos.pieces(PAWN, Them) & attack_span_mask(Us, s))) + score += evaluate_outposts(pos, ei, s); + + // Queen or rook on 7th rank + if ( (Piece == ROOK || Piece == QUEEN) + && relative_rank(Us, s) == RANK_7 + && relative_rank(Us, pos.king_square(Them)) == RANK_8) + { + score += (Piece == ROOK ? RookOn7thBonus : QueenOn7thBonus); } - if (Piece == ROOK || Piece == QUEEN) + // Special extra evaluation for bishops + if (Piece == BISHOP && pos.is_chess960()) { - // Queen or rook on 7th rank - if ( relative_rank(Us, s) == RANK_7 - && relative_rank(Us, pos.king_square(Them)) == RANK_8) + // 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 (s == relative_square(Us, SQ_A1) || s == relative_square(Us, SQ_H1)) { - ei.mgValue += Sign[Us] * (Piece == ROOK ? MidgameRookOn7thBonus : MidgameQueenOn7thBonus); - ei.egValue += Sign[Us] * (Piece == ROOK ? EndgameRookOn7thBonus : EndgameQueenOn7thBonus); + Square d = pawn_push(Us) + (file_of(s) == FILE_A ? DELTA_E : DELTA_W); + if (pos.piece_on(s + d) == make_piece(Us, PAWN)) + { + if (!pos.square_is_empty(s + d + pawn_push(Us))) + score -= 2*TrappedBishopA1H1Penalty; + else if (pos.piece_on(s + 2*d) == make_piece(Us, PAWN)) + score -= TrappedBishopA1H1Penalty; + else + score -= TrappedBishopA1H1Penalty / 2; + } } } @@ -656,19 +626,13 @@ namespace { if (Piece == ROOK) { // Open and half-open files - f = square_file(s); + f = file_of(s); if (ei.pi->file_is_half_open(Us, f)) { if (ei.pi->file_is_half_open(Them, f)) - { - ei.mgValue += Sign[Us] * RookOpenFileBonus; - ei.egValue += Sign[Us] * RookOpenFileBonus; - } + score += RookOpenFileBonus; else - { - ei.mgValue += Sign[Us] * RookHalfOpenFileBonus; - ei.egValue += Sign[Us] * RookHalfOpenFileBonus; - } + score += RookHalfOpenFileBonus; } // Penalize rooks which are trapped inside a king. Penalize more if @@ -678,320 +642,292 @@ namespace { ksq = pos.king_square(Us); - if ( square_file(ksq) >= FILE_E - && square_file(s) > square_file(ksq) - && (relative_rank(Us, ksq) == RANK_1 || square_rank(ksq) == square_rank(s))) + if ( file_of(ksq) >= FILE_E + && file_of(s) > file_of(ksq) + && (relative_rank(Us, ksq) == RANK_1 || rank_of(ksq) == rank_of(s))) { // Is there a half-open file between the king and the edge of the board? - if (!ei.pi->has_open_file_to_right(Us, square_file(ksq))) - ei.mgValue -= pos.can_castle(Us)? Sign[Us] * ((TrappedRookPenalty - mob * 16) / 2) - : Sign[Us] * (TrappedRookPenalty - mob * 16); + if (!ei.pi->has_open_file_to_right(Us, file_of(ksq))) + score -= make_score(pos.can_castle(Us) ? (TrappedRookPenalty - mob * 16) / 2 + : (TrappedRookPenalty - mob * 16), 0); } - else if ( square_file(ksq) <= FILE_D - && square_file(s) < square_file(ksq) - && (relative_rank(Us, ksq) == RANK_1 || square_rank(ksq) == square_rank(s))) + else if ( file_of(ksq) <= FILE_D + && file_of(s) < file_of(ksq) + && (relative_rank(Us, ksq) == RANK_1 || rank_of(ksq) == rank_of(s))) { // Is there a half-open file between the king and the edge of the board? - if (!ei.pi->has_open_file_to_left(Us, square_file(ksq))) - ei.mgValue -= pos.can_castle(Us)? Sign[Us] * ((TrappedRookPenalty - mob * 16) / 2) - : Sign[Us] * (TrappedRookPenalty - mob * 16); + if (!ei.pi->has_open_file_to_left(Us, file_of(ksq))) + score -= make_score(pos.can_castle(Us) ? (TrappedRookPenalty - mob * 16) / 2 + : (TrappedRookPenalty - mob * 16), 0); } } } + + if (Trace) + TracedScores[Us][Piece] = 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, EvalInfo& ei) { + + const Color Them = (Us == WHITE ? BLACK : WHITE); + + Bitboard b, undefended, undefendedMinors, weakEnemies; + Score score = SCORE_ZERO; + + // Undefended pieces get penalized even if not under attack + undefended = pos.pieces(Them) & ~ei.attackedBy[Them][0]; + undefendedMinors = undefended & (pos.pieces(BISHOP) | pos.pieces(KNIGHT)); + + if (undefendedMinors) + score += single_bit(undefendedMinors) ? UndefendedPiecePenalty + : UndefendedPiecePenalty * 2; + if (undefended & pos.pieces(ROOK)) + score += UndefendedPiecePenalty; + + // Enemy pieces not defended by a pawn and under our attack + weakEnemies = pos.pieces(Them) + & ~ei.attackedBy[Them][PAWN] + & ei.attackedBy[Us][0]; + + if (!weakEnemies) + return score; + + // 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. + 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 += ThreatBonus[pt1][pt2]; + } + return score; } // evaluate_pieces_of_color<>() assigns bonuses and penalties to all the // pieces of a given color. - template - void evaluate_pieces_of_color(const Position& pos, EvalInfo& ei) { + 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; - evaluate_pieces(pos, ei); - evaluate_pieces(pos, ei); - evaluate_pieces(pos, ei); - evaluate_pieces(pos, ei); + // 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)); - // Sum up all attacked squares - ei.attackedBy[Us][0] = ei.attackedBy[Us][PAWN] | ei.attackedBy[Us][KNIGHT] - | ei.attackedBy[Us][BISHOP] | ei.attackedBy[Us][ROOK] - | ei.attackedBy[Us][QUEEN] | ei.attackedBy[Us][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][0] = ei.attackedBy[Us][PAWN] | ei.attackedBy[Us][KNIGHT] + | ei.attackedBy[Us][BISHOP] | ei.attackedBy[Us][ROOK] + | ei.attackedBy[Us][QUEEN] | ei.attackedBy[Us][KING]; + return score; } // evaluate_king<>() assigns bonuses and penalties to a king of a given color - template - void evaluate_king(const Position& pos, EvalInfo& ei) { + template + Score evaluate_king(const Position& pos, EvalInfo& ei, Value margins[]) { const Color Them = (Us == WHITE ? BLACK : WHITE); - const Square s = pos.king_square(Us); - int shelter = 0; + + Bitboard undefended, b, b1, b2, safe; + int attackUnits; + const Square ksq = pos.king_square(Us); // King shelter - if (relative_rank(Us, s) <= RANK_4) - { - shelter = ei.pi->get_king_shelter(pos, Us, s); - ei.mgValue += Sign[Us] * Value(shelter); - } + Score score = ei.pi->king_shelter(pos, ksq); // King safety. This is quite complicated, and is almost certainly far // from optimally tuned. - if ( pos.piece_count(Them, QUEEN) >= 1 - && ei.kingAttackersCount[Them] >= 2 - && pos.non_pawn_material(Them) >= QueenValueMidgame + RookValueMidgame + if ( ei.kingAttackersCount[Them] >= 2 && ei.kingAdjacentZoneAttacksCount[Them]) { - // Is it the attackers turn to move? - bool sente = (Them == pos.side_to_move()); - - // Find the attacked squares around the king which has no defenders - // apart from the king itself - Bitboard undefended = - ei.attacked_by(Them) & ~ei.attacked_by(Us, PAWN) - & ~ei.attacked_by(Us, KNIGHT) & ~ei.attacked_by(Us, BISHOP) - & ~ei.attacked_by(Us, ROOK) & ~ei.attacked_by(Us, QUEEN) - & ei.attacked_by(Us, KING); - - Bitboard occ = pos.occupied_squares(), b, b2; - - // Initialize the 'attackUnits' variable, which is used later on as an - // index to the SafetyTable[] array. The initial value is based on the - // number and types of the attacking pieces, the number of attacked and - // undefended squares around the king, the square of the king, and the - // quality of the pawn shelter. - int attackUnits = - Min((ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them]) / 2, 25) - + (ei.kingAdjacentZoneAttacksCount[Them] + count_1s_max_15(undefended)) * 3 - + InitKingDanger[relative_square(Us, s)] - (shelter >> 5); - - // Analyse safe queen contact checks - b = undefended & ei.attacked_by(Them, QUEEN) & ~pos.pieces_of_color(Them); - if (b) - { - Bitboard attackedByOthers = - ei.attacked_by(Them, PAWN) | ei.attacked_by(Them, KNIGHT) - | ei.attacked_by(Them, BISHOP) | ei.attacked_by(Them, ROOK); - - b &= attackedByOthers; + // Find the attacked squares around the king which has no defenders + // apart from the king itself + undefended = ei.attackedBy[Them][0] & ei.attackedBy[Us][KING]; + undefended &= ~( 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 KingDangerTable[] 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) + + 3 * (ei.kingAdjacentZoneAttacksCount[Them] + popcount(undefended)) + + InitKingDanger[relative_square(Us, ksq)] + - mg_value(ei.pi->king_shelter(pos, ksq)) / 32; + + // Analyse enemy's safe queen contact checks. First find undefended + // squares around the king attacked by enemy queen... + b = undefended & ei.attackedBy[Them][QUEEN] & ~pos.pieces(Them); if (b) { - // The bitboard b now contains the squares available for safe queen - // contact checks. - int count = count_1s_max_15(b); - attackUnits += QueenContactCheckBonus * count * (sente ? 2 : 1); - - // Is there a mate threat? - if (QueenContactMates && !pos.is_check()) - { - Bitboard escapeSquares = - pos.attacks_from(s) & ~pos.pieces_of_color(Us) & ~attackedByOthers; - - while (b) - { - Square from, to = pop_1st_bit(&b); - if (!(escapeSquares & ~queen_attacks_bb(to, occ & ClearMaskBB[s]))) - { - // We have a mate, unless the queen is pinned or there - // is an X-ray attack through the queen. - for (int i = 0; i < pos.piece_count(Them, QUEEN); i++) - { - from = pos.piece_list(Them, QUEEN, i); - if ( bit_is_set(pos.attacks_from(from), to) - && !bit_is_set(pos.pinned_pieces(Them), from) - && !(rook_attacks_bb(to, occ & ClearMaskBB[from]) & pos.pieces(ROOK, QUEEN, Us)) - && !(bishop_attacks_bb(to, occ & ClearMaskBB[from]) & pos.pieces(BISHOP, QUEEN, Us))) - - ei.mateThreat[Them] = make_move(from, to); - } - } - } - } + // ...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 += QueenContactCheckBonus + * popcount(b) + * (Them == pos.side_to_move() ? 2 : 1); } - } - // Analyse safe distance checks - if (QueenCheckBonus > 0 || RookCheckBonus > 0) - { - b = pos.attacks_from(s) & ~pos.pieces_of_color(Them) & ~ei.attacked_by(Us); + // Analyse enemy's safe rook contact checks. First find undefended + // squares around the king attacked by enemy rooks... + b = undefended & ei.attackedBy[Them][ROOK] & ~pos.pieces(Them); - // Queen checks - b2 = b & ei.attacked_by(Them, QUEEN); - if (b2) - attackUnits += QueenCheckBonus * count_1s_max_15(b2); + // Consider only squares where the enemy rook gives check + b &= PseudoAttacks[ROOK][ksq]; - // Rook checks - b2 = b & ei.attacked_by(Them, ROOK); - if (b2) - attackUnits += RookCheckBonus * count_1s_max_15(b2); - } - if (QueenCheckBonus > 0 || BishopCheckBonus > 0) - { - b = pos.attacks_from(s) & ~pos.pieces_of_color(Them) & ~ei.attacked_by(Us); + if (b) + { + // ...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 += RookContactCheckBonus + * popcount(b) + * (Them == pos.side_to_move() ? 2 : 1); + } - // Queen checks - b2 = b & ei.attacked_by(Them, QUEEN); - if (b2) - attackUnits += QueenCheckBonus * count_1s_max_15(b2); + // Analyse enemy's safe distance checks for sliders and knights + safe = ~(pos.pieces(Them) | ei.attackedBy[Us][0]); - // Bishop checks - b2 = b & ei.attacked_by(Them, BISHOP); - if (b2) - attackUnits += BishopCheckBonus * count_1s_max_15(b2); - } - if (KnightCheckBonus > 0) - { - b = pos.attacks_from(s) & ~pos.pieces_of_color(Them) & ~ei.attacked_by(Us); + b1 = pos.attacks_from(ksq) & safe; + b2 = pos.attacks_from(ksq) & safe; - // Knight checks - b2 = b & ei.attacked_by(Them, KNIGHT); - if (b2) - attackUnits += KnightCheckBonus * count_1s_max_15(b2); - } + // Enemy queen safe checks + b = (b1 | b2) & ei.attackedBy[Them][QUEEN]; + if (b) + attackUnits += QueenCheckBonus * popcount(b); - // Analyse discovered checks (only for non-pawns right now, consider - // adding pawns later). - if (DiscoveredCheckBonus) - { - b = pos.discovered_check_candidates(Them) & ~pos.pieces(PAWN); + // Enemy rooks safe checks + b = b1 & ei.attackedBy[Them][ROOK]; if (b) - attackUnits += DiscoveredCheckBonus * count_1s_max_15(b) * (sente ? 2 : 1); - } + attackUnits += RookCheckBonus * popcount(b); + + // Enemy bishops safe checks + b = b2 & ei.attackedBy[Them][BISHOP]; + if (b) + attackUnits += BishopCheckBonus * popcount(b); - // Has a mate threat been found? We don't do anything here if the - // side with the mating move is the side to move, because in that - // case the mating side will get a huge bonus at the end of the main - // evaluation function instead. - if (ei.mateThreat[Them] != MOVE_NONE) - attackUnits += MateThreatBonus; - - // Ensure that attackUnits is between 0 and 99, in order to avoid array - // out of bounds errors: - if (attackUnits < 0) - attackUnits = 0; - - if (attackUnits >= 100) - attackUnits = 99; - - // Finally, extract the king safety score from the SafetyTable[] array. - // Add the score to the evaluation, and also to ei.futilityMargin. The - // reason for adding the king safety score to the futility margin is - // that the king safety scores can sometimes be very big, and that - // capturing a single attacking piece can therefore result in a score - // change far bigger than the value of the captured piece. - Value v = apply_weight(SafetyTable[attackUnits], WeightKingSafety[Us]); - - ei.mgValue -= Sign[Us] * v; - - if (Us == pos.side_to_move()) - ei.futilityMargin += v; + // Enemy knights safe checks + b = pos.attacks_from(ksq) & ei.attackedBy[Them][KNIGHT] & safe; + if (b) + attackUnits += KnightCheckBonus * popcount(b); + + // To index KingDangerTable[] attackUnits must be in [0, 99] range + attackUnits = std::min(99, std::max(0, attackUnits)); + + // Finally, extract the king danger score from the KingDangerTable[] + // 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 -= KingDangerTable[Us == Eval::RootColor][attackUnits]; + margins[Us] += mg_value(KingDangerTable[Us == Eval::RootColor][attackUnits]); } + + if (Trace) + TracedScores[Us][KING] = 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 - void evaluate_passed_pawns_of_color(const Position& pos, int movesToGo[], EvalInfo& ei) { + Score evaluate_passed_pawns(const Position& pos, EvalInfo& ei) { const Color Them = (Us == WHITE ? BLACK : WHITE); - Bitboard b2, b3, b4; - Square ourKingSq = pos.king_square(Us); - Square theirKingSq = pos.king_square(Them); - Bitboard b = ei.pi->passed_pawns() & pos.pieces(PAWN, Us); + Bitboard b, squaresToQueen, defendedSquares, unsafeSquares, supportingPawns; + Score score = SCORE_ZERO; - while (b) - { + b = ei.pi->passed_pawns(Us); + + if (!b) + return SCORE_ZERO; + + do { Square s = pop_1st_bit(&b); - assert(pos.piece_on(s) == piece_of_color_and_type(Us, PAWN)); assert(pos.pawn_is_passed(Us, s)); int r = int(relative_rank(Us, s) - RANK_2); - int tr = Max(0, r * (r - 1)); + int rr = r * (r - 1); // Base bonus based on rank - Value mbonus = Value(20 * tr); - Value ebonus = Value(10 + r * r * 10); + Value mbonus = Value(20 * rr); + Value ebonus = Value(10 * (rr + r + 1)); - // Adjust bonus based on king proximity - if (tr) + if (rr) { Square blockSq = s + pawn_push(Us); - ebonus -= Value(square_distance(ourKingSq, blockSq) * 3 * tr); - ebonus -= Value(square_distance(ourKingSq, blockSq + pawn_push(Us)) * 1 * tr); - ebonus += Value(square_distance(theirKingSq, blockSq) * 6 * tr); + // 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); + + // 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 the pawn is free to advance, increase bonus if (pos.square_is_empty(blockSq)) { - // There are no enemy pawns in the pawn's path - b2 = squares_in_front_of(Us, s); - - assert((b2 & pos.pieces(PAWN, Them)) == EmptyBoardBB); - - // Squares attacked by us - b4 = b2 & ei.attacked_by(Us); - - // Squares attacked or occupied by enemy pieces - b3 = b2 & (ei.attacked_by(Them) | pos.pieces_of_color(Them)); + squaresToQueen = squares_in_front_of(Us, s); + defendedSquares = squaresToQueen & ei.attackedBy[Us][0]; // If there is an enemy rook or queen attacking the pawn from behind, - // add all X-ray attacks by the rook or queen. - if ( (squares_behind(Us, s) & pos.pieces(ROOK, QUEEN, Them)) - && (squares_behind(Us, s) & pos.pieces(ROOK, QUEEN, Them) & pos.attacks_from(s))) - b3 = b2; - - // Are any of the squares in the pawn's path attacked or occupied by the enemy? - if (b3 == EmptyBoardBB) - // No enemy attacks or pieces, huge bonus! - // Even bigger if we protect the pawn's path - ebonus += Value(tr * (b2 == b4 ? 17 : 15)); + // 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 ( (squares_in_front_of(Them, s) & pos.pieces(ROOK, QUEEN, Them)) + && (squares_in_front_of(Them, s) & pos.pieces(ROOK, QUEEN, Them) & pos.attacks_from(s))) + unsafeSquares = squaresToQueen; + else + unsafeSquares = squaresToQueen & (ei.attackedBy[Them][0] | pos.pieces(Them)); + + // If there aren't enemy attacks or pieces along the path to queen give + // huge bonus. Even bigger if we protect the pawn's path. + if (!unsafeSquares) + ebonus += Value(rr * (squaresToQueen == defendedSquares ? 17 : 15)); else // OK, there are enemy attacks or pieces (but not pawns). Are those // squares which are attacked by the enemy also attacked by us ? // If yes, big bonus (but smaller than when there are no enemy attacks), // if no, somewhat smaller bonus. - ebonus += Value(tr * ((b3 & b4) == b3 ? 13 : 8)); - - // At last, add a small bonus when there are no *friendly* pieces - // in the pawn's path. - if ((b2 & pos.pieces_of_color(Us)) == EmptyBoardBB) - ebonus += Value(tr); + ebonus += Value(rr * ((unsafeSquares & defendedSquares) == unsafeSquares ? 13 : 8)); } - } // tr != 0 + } // rr != 0 - // If the pawn is supported by a friendly pawn, increase bonus - b2 = pos.pieces(PAWN, Us) & neighboring_files_bb(s); - if (b2 & rank_bb(s)) + // 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(PAWN, Us) & adjacent_files_bb(file_of(s)); + if (supportingPawns & rank_bb(s)) ebonus += Value(r * 20); - else if (pos.attacks_from(s, Them) & b2) - ebonus += Value(r * 12); - - // If the other side has only a king, check whether the pawn is - // unstoppable - if (pos.non_pawn_material(Them) == Value(0)) - { - Square qsq; - int d; - qsq = relative_square(Us, make_square(square_file(s), RANK_8)); - d = square_distance(s, qsq) - - square_distance(theirKingSq, qsq) - + (Us != pos.side_to_move()); - - if (d < 0) - { - int mtg = RANK_8 - relative_rank(Us, s); - int blockerCount = count_1s_max_15(squares_in_front_of(Us,s) & pos.occupied_squares()); - mtg += blockerCount; - d += blockerCount; - if (d < 0) - movesToGo[Us] = movesToGo[Us] ? Min(movesToGo[Us], mtg) : mtg; - } - } + 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 @@ -999,126 +935,180 @@ namespace { // 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 (square_file(s) == FILE_A || square_file(s) == FILE_H) + if (file_of(s) == FILE_A || file_of(s) == FILE_H) { - if ( pos.non_pawn_material(Them) <= KnightValueMidgame - && pos.piece_count(Them, KNIGHT) <= 1) + if (pos.non_pawn_material(Them) <= KnightValueMidgame) ebonus += ebonus / 4; else if (pos.pieces(ROOK, QUEEN, Them)) ebonus -= ebonus / 4; } + score += make_score(mbonus, ebonus); - // Add the scores for this pawn to the middle game and endgame eval. - ei.mgValue += apply_weight(Sign[Us] * mbonus, WeightPassedPawnsMidgame); - ei.egValue += apply_weight(Sign[Us] * ebonus, WeightPassedPawnsEndgame); + } while (b); - } // while + // Add the scores to the middle game and endgame eval + return apply_weight(score, Weights[PassedPawns]); } - // evaluate_passed_pawns() evaluates the passed pawns for both sides - - void evaluate_passed_pawns(const Position& pos, EvalInfo& ei) { + // 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. - int movesToGo[2] = {0, 0}; + Score evaluate_unstoppable_pawns(const Position& pos, EvalInfo& ei) { - // Evaluate pawns for each color - evaluate_passed_pawns_of_color(pos, movesToGo, ei); - evaluate_passed_pawns_of_color(pos, movesToGo, 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 }; - // Does either side have an unstoppable passed pawn? - if (movesToGo[WHITE] && !movesToGo[BLACK]) - ei.egValue += UnstoppablePawnValue - Value(0x40 * movesToGo[WHITE]); - else if (movesToGo[BLACK] && !movesToGo[WHITE]) - ei.egValue -= UnstoppablePawnValue - Value(0x40 * movesToGo[BLACK]); - else if (movesToGo[BLACK] && movesToGo[WHITE]) + // 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++) { - // Both sides have unstoppable pawns! Try to find out who queens - // first. We begin by transforming 'movesToGo' to the number of - // plies until the pawn queens for both sides. - movesToGo[WHITE] *= 2; - movesToGo[BLACK] *= 2; - movesToGo[pos.side_to_move()]--; - - // If one side queens at least three plies before the other, that - // side wins. - if (movesToGo[WHITE] <= movesToGo[BLACK] - 3) - ei.egValue += UnstoppablePawnValue - Value(0x40 * (movesToGo[WHITE]/2)); - else if (movesToGo[BLACK] <= movesToGo[WHITE] - 3) - ei.egValue -= UnstoppablePawnValue - Value(0x40 * (movesToGo[BLACK]/2)); - - // We could also add some rules about the situation when one side - // queens exactly one ply before the other: Does the first queen - // check the opponent's king, or attack the opponent's queening square? - // This is slightly tricky to get right, because it is possible that - // the opponent's king has moved somewhere before the first pawn queens. - } - } + // Skip if other side has non-pawn pieces + if (pos.non_pawn_material(~c)) + continue; + b = ei.pi->passed_pawns(c); - // evaluate_trapped_bishop_a7h7() determines whether a bishop on a7/h7 - // (a2/h2 for black) is trapped by enemy pawns, and assigns a penalty - // if it is. + while (b) + { + s = pop_1st_bit(&b); + queeningSquare = relative_square(c, make_square(file_of(s), RANK_8)); + queeningPath = squares_in_front_of(c, s); - void evaluate_trapped_bishop_a7h7(const Position& pos, Square s, Color us, EvalInfo &ei) { + // 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][0] & queeningPath) == queeningPath); - assert(square_is_ok(s)); - assert(pos.piece_on(s) == piece_of_color_and_type(us, BISHOP)); + if (movesToGo >= oppMovesToGo && !pathDefended) + continue; - Square b6 = relative_square(us, (square_file(s) == FILE_A) ? SQ_B6 : SQ_G6); - Square b8 = relative_square(us, (square_file(s) == FILE_A) ? SQ_B8 : SQ_G8); + // Opponent king cannot block because path is defended and position + // is not in check. So only friendly pieces can be blockers. + assert(!pos.in_check()); + assert((queeningPath & pos.pieces()) == (queeningPath & pos.pieces(c))); - if ( pos.piece_on(b6) == piece_of_color_and_type(opposite_color(us), PAWN) - && pos.see(s, b6) < 0 - && pos.see(s, b8) < 0) - { - ei.mgValue -= Sign[us] * TrappedBishopA7H7Penalty; - ei.egValue -= Sign[us] * TrappedBishopA7H7Penalty; - } - } + // Add moves needed to free the path from friendly pieces and retest condition + movesToGo += popcount(queeningPath & pos.pieces(c)); + if (movesToGo >= oppMovesToGo && !pathDefended) + continue; - // evaluate_trapped_bishop_a1h1() determines whether a bishop on a1/h1 - // (a8/h8 for black) is trapped by a friendly pawn on b2/g2 (b7/g7 for - // black), and assigns a penalty if it is. This pattern can obviously - // only occur in Chess960 games. + pliesToGo = 2 * movesToGo - int(c == pos.side_to_move()); + pliesToQueen[c] = std::min(pliesToQueen[c], pliesToGo); + } + } - void evaluate_trapped_bishop_a1h1(const Position& pos, Square s, Color us, EvalInfo& ei) { + // 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; - Piece pawn = piece_of_color_and_type(us, PAWN); - Square b2, b3, c3; + winnerSide = (pliesToQueen[WHITE] < pliesToQueen[BLACK] ? WHITE : BLACK); + loserSide = ~winnerSide; - assert(Chess960); - assert(square_is_ok(s)); - assert(pos.piece_on(s) == piece_of_color_and_type(us, BISHOP)); + // Step 3. Can the losing side possibly create a new passed pawn and thus prevent the loss? + b = candidates = pos.pieces(PAWN, loserSide); - if (square_file(s) == FILE_A) - { - b2 = relative_square(us, SQ_B2); - b3 = relative_square(us, SQ_B3); - c3 = relative_square(us, SQ_C3); - } - else + while (b) { - b2 = relative_square(us, SQ_G2); - b3 = relative_square(us, SQ_G3); - c3 = relative_square(us, SQ_F3); + s = pop_1st_bit(&b); + + // Compute plies from queening + queeningSquare = relative_square(loserSide, make_square(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()); + + // Check if (without even considering any obstacles) we're too far away or doubled + if ( pliesToQueen[winnerSide] + 3 <= pliesToGo + || (squares_in_front_of(loserSide, s) & pos.pieces(PAWN, loserSide))) + candidates ^= s; } - if (pos.piece_on(b2) == pawn) + // 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; + + // Step 4. Check new passed pawn creation through king capturing and pawn sacrifices + b = candidates; + + while (b) { - Value penalty; + s = pop_1st_bit(&b); + sacptg = blockersCount = 0; + minKingDist = kingptg = 256; - if (!pos.square_is_empty(b3)) - penalty = 2*TrappedBishopA1H1Penalty; - else if (pos.piece_on(c3) == pawn) - penalty = TrappedBishopA1H1Penalty; - else - penalty = TrappedBishopA1H1Penalty / 2; + // Compute plies from queening + queeningSquare = relative_square(loserSide, make_square(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()); + + // Generate list of blocking pawns and supporters + supporters = adjacent_files_bb(file_of(s)) & candidates; + opposed = squares_in_front_of(loserSide, s) & pos.pieces(PAWN, winnerSide); + blockers = passed_pawn_mask(loserSide, s) & pos.pieces(PAWN, winnerSide); + + assert(blockers); + + // How many plies does it take to remove all the blocking pawns? + while (blockers) + { + blockSq = pop_1st_bit(&blockers); + movesToGo = 256; + + // 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, blockSq + pawn_push(winnerSide)); + + while (b2) // This while-loop could be replaced with LSB/MSB (depending on color) + { + d = square_distance(blockSq, pop_1st_bit(&b2)) - 2; + movesToGo = std::min(movesToGo, d); + } + } + + // Check pawns that can be sacrificed against the blocking pawn + b2 = attack_span_mask(winnerSide, blockSq) & candidates & ~(1ULL << s); + + while (b2) // This while-loop could be replaced with LSB/MSB (depending on color) + { + d = square_distance(blockSq, pop_1st_bit(&b2)) - 2; + movesToGo = std::min(movesToGo, d); + } + + // 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; + + // Plies needed to sacrifice against all the blocking pawns + sacptg += movesToGo * 2; + blockersCount++; + + // 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; + } - ei.mgValue -= Sign[us] * penalty; - ei.egValue -= Sign[us] * penalty; + // Check if pawn sacrifice plan _may_ save the day + if (pliesToQueen[winnerSide] + 3 > pliesToGo + sacptg) + return SCORE_ZERO; + + // Check if king capture plan _may_ save the day (contains some false positives) + if (pliesToQueen[winnerSide] + 3 > pliesToGo + kingptg) + return SCORE_ZERO; } + + // Winning pawn is unstoppable and will promote as first, return big score + Score score = make_score(0, (Value) 0x500 - 0x20 * pliesToQueen[winnerSide]); + return winnerSide == WHITE ? score : -score; } @@ -1127,107 +1117,100 @@ namespace { // 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. - template - void evaluate_space(const Position& pos, EvalInfo& ei) { + // material hash table. The aim is to improve play on game opening. + template + int evaluate_space(const Position& pos, EvalInfo& ei) { const Color Them = (Us == WHITE ? BLACK : WHITE); // Find the safe squares for our pieces inside the area defined by - // SpaceMask[us]. 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] + & ~pos.pieces(PAWN, Us) + & ~ei.attackedBy[Them][PAWN] + & (ei.attackedBy[Us][0] | ~ei.attackedBy[Them][0]); - Bitboard safeSquares = SpaceMask[Us] - & ~pos.pieces(PAWN, Us) - & ~ei.attacked_by(Them, PAWN) - & ~(~ei.attacked_by(Us) & ei.attacked_by(Them)); - - // Find all squares which are at most three squares behind some friendly - // pawn. - Bitboard behindFriendlyPawns = pos.pieces(PAWN, Us); - behindFriendlyPawns |= (Us == WHITE ? behindFriendlyPawns >> 8 : behindFriendlyPawns << 8); - behindFriendlyPawns |= (Us == WHITE ? behindFriendlyPawns >> 16 : behindFriendlyPawns << 16); + // Find all squares which are at most three squares behind some friendly pawn + Bitboard behind = pos.pieces(PAWN, Us); + behind |= (Us == WHITE ? behind >> 8 : behind << 8); + behind |= (Us == WHITE ? behind >> 16 : behind << 16); - int space = count_1s_max_15(safeSquares) - + count_1s_max_15(behindFriendlyPawns & safeSquares); - - ei.mgValue += Sign[Us] * apply_weight(Value(space * ei.mi->space_weight()), WeightSpace); + return popcount(safe) + popcount(behind & safe); } - // apply_weight() applies an evaluation weight to a value + // apply_weight() applies an evaluation weight to a value trying to prevent overflow - inline Value apply_weight(Value v, int w) { - return (v*w) / 0x100; + inline 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); } - // scale_by_game_phase() interpolates between a middle game and an endgame - // score, based on game phase. It also scales the return value by a - // ScaleFactor array. + // scale_by_game_phase() interpolates between a middle game and an endgame score, + // based on game phase. It also scales the return value by a ScaleFactor array. - Value scale_by_game_phase(Value mv, Value ev, Phase ph, const ScaleFactor sf[]) { + Value scale_by_game_phase(const Score& v, Phase ph, ScaleFactor sf) { - assert(mv > -VALUE_INFINITE && mv < VALUE_INFINITE); - assert(ev > -VALUE_INFINITE && ev < VALUE_INFINITE); + 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); - ev = apply_scale_factor(ev, sf[(ev > Value(0) ? WHITE : BLACK)]); - - Value result = Value(int((mv * ph + ev * (128 - ph)) / 128)); - return Value(int(result) & ~(GrainSize - 1)); + 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)); } // weight_option() computes the value of an evaluation weight, by combining - // an UCI-configurable weight with an internal weight. + // two UCI-configurable weights (midgame and endgame) with an internal weight. - int weight_option(const std::string& opt, int internalWeight) { + Score weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight) { - int uciWeight = get_option_value_int(opt); - uciWeight = (uciWeight * 0x100) / 100; - return (uciWeight * internalWeight) / 0x100; - } + // Scale option value from 100 to 256 + int mg = Options[mgOpt] * 256 / 100; + int eg = Options[egOpt] * 256 / 100; + return apply_weight(make_score(mg, eg), internalWeight); + } - // init_safety() initizes the king safety evaluation, based on UCI - // parameters. It is called from read_weights(). - void init_safety() { + // A couple of little helpers used by tracing code, to_cp() converts a value to + // a double in centipawns scale, trace_add() stores white and black scores. - QueenContactCheckBonus = get_option_value_int("Queen Contact Check Bonus"); - QueenCheckBonus = get_option_value_int("Queen Check Bonus"); - RookCheckBonus = get_option_value_int("Rook Check Bonus"); - BishopCheckBonus = get_option_value_int("Bishop Check Bonus"); - KnightCheckBonus = get_option_value_int("Knight Check Bonus"); - DiscoveredCheckBonus = get_option_value_int("Discovered Check Bonus"); - MateThreatBonus = get_option_value_int("Mate Threat Bonus"); + double to_cp(Value v) { return double(v) / double(PawnValueMidgame); } - int maxSlope = get_option_value_int("King Safety Max Slope"); - int peak = get_option_value_int("King Safety Max Value") * 256 / 100; - double a = get_option_value_int("King Safety Coefficient") / 100.0; - double b = get_option_value_int("King Safety X Intercept"); - bool quad = (get_option_value_string("King Safety Curve") == "Quadratic"); - bool linear = (get_option_value_string("King Safety Curve") == "Linear"); + void trace_add(int idx, Score wScore, Score bScore) { - for (int i = 0; i < 100; i++) - { - if (i < b) - SafetyTable[i] = Value(0); - else if (quad) - SafetyTable[i] = Value((int)(a * (i - b) * (i - b))); - else if (linear) - SafetyTable[i] = Value((int)(100 * a * (i - b))); - } + TracedScores[WHITE][idx] = wScore; + TracedScores[BLACK][idx] = bScore; + } - for (int i = 0; i < 100; i++) - { - if (SafetyTable[i+1] - SafetyTable[i] > maxSlope) - for (int j = i + 1; j < 100; j++) - SafetyTable[j] = SafetyTable[j-1] + Value(maxSlope); - if (SafetyTable[i] > Value(peak)) - SafetyTable[i] = Value(peak); + // trace_row() is an helper function used by tracing code to register the + // values of a single evaluation term. + + void trace_row(const char* name, int idx) { + + Score wScore = TracedScores[WHITE][idx]; + Score bScore = TracedScores[BLACK][idx]; + + switch (idx) { + case PST: case IMBALANCE: case PAWN: case UNSTOPPABLE: case TOTAL: + TraceStream << std::setw(20) << name << " | --- --- | --- --- | " + << std::setw(6) << to_cp(mg_value(wScore)) << " " + << std::setw(6) << to_cp(eg_value(wScore)) << " \n"; + break; + default: + TraceStream << 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"; } } }