X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fevaluate.cpp;h=5e4f4bdd6dc71749b22aba8417a7b5d2ed098664;hp=2e1465ff7b8a904966eae06b8623ea73e6bb1482;hb=4c95edddbf1aaec22c343adaca4796df0137e4c3;hpb=cccf3c815c2f2be884fac4248a2be91b6823df8a diff --git a/src/evaluate.cpp b/src/evaluate.cpp index 2e1465ff..5e4f4bdd 100644 --- a/src/evaluate.cpp +++ b/src/evaluate.cpp @@ -2,6 +2,7 @@ Stockfish, a UCI chess playing engine derived from Glaurung 2.1 Copyright (C) 2004-2008 Tord Romstad (Glaurung author) 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 @@ -23,7 +24,7 @@ #include #include -#include "bitcount.h" +#include "bitboard.h" #include "evaluate.h" #include "material.h" #include "pawns.h" @@ -32,7 +33,7 @@ namespace { namespace Trace { - enum Term { // First 8 entries are for PieceType + enum Term { // The first 8 entries are for PieceType MATERIAL = 8, IMBALANCE, MOBILITY, THREAT, PASSED, SPACE, TOTAL, TERM_NB }; @@ -76,6 +77,11 @@ namespace { // 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) @@ -88,7 +94,7 @@ 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 elements in the // KingAttackWeights array. @@ -102,106 +108,95 @@ namespace { int kingAdjacentZoneAttacksCount[COLOR_NB]; Bitboard pinnedPieces[COLOR_NB]; + Material::Entry* me; Pawns::Entry* pi; }; - - // Evaluation weights, indexed by the corresponding evaluation term - enum { Mobility, PawnStructure, PassedPawns, Space, KingSafety }; - - const struct Weight { int mg, eg; } Weights[] = { - {289, 344}, {233, 201}, {221, 273}, {46, 0}, {322, 0} - }; - - Score operator*(Score s, const Weight& w) { - return make_score(mg_value(s) * w.mg / 256, eg_value(s) * w.eg / 256); - } - - #define V(v) Value(v) #define S(mg, eg) make_score(mg, eg) // MobilityBonus[PieceType][attacked] contains bonuses for middle and end - // game, indexed by piece type and number of attacked squares not occupied by - // friendly pieces. + // game, indexed by piece type and number of attacked squares in the MobilityArea. const Score MobilityBonus[][32] = { {}, {}, - { S(-70,-52), S(-52,-37), S( -7,-17), S( 0, -6), S( 8, 5), S( 16, 9), // Knights - S( 23, 20), S( 31, 21), S( 36, 22) }, - { S(-49,-44), S(-22,-13), S( 16, 0), S( 27, 11), S( 38, 19), S( 52, 34), // Bishops - S( 56, 44), S( 65, 47), S( 67, 51), S( 73, 56), S( 81, 59), S( 83, 69), - S( 95, 72), S(100, 75) }, - { S(-49,-57), S(-22,-14), S(-10, 18), S( -5, 39), S( -4, 50), S( -2, 58), // Rooks - S( 6, 78), S( 11, 86), S( 17, 92), S( 19,103), S( 26,111), S( 27,115), - S( 36,119), S( 41,121), S( 50,122) }, - { S(-41,-24), S(-26, -8), S( 0, 6), S( 2, 14), S( 12, 27), S( 21, 40), // Queens - S( 22, 45), S( 37, 55), S( 40, 57), S( 43, 63), S( 50, 68), S( 52, 74), - S( 56, 80), S( 66, 84), S( 68, 85), S( 69, 88), S( 71, 92), S( 72, 94), - S( 80, 96), S( 89, 98), S( 94,101), S(102,113), S(106,114), S(107,116), - S(112,125), S(113,127), S(117,137), S(122,143) } - }; - - // Mask of allowed outpost squares indexed by color - const Bitboard OutpostMask[COLOR_NB] = { - Rank4BB | Rank5BB | Rank6BB, Rank5BB | Rank4BB | Rank3BB + { 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[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(42,11), S(63,17) }, // Knights - { S(18, 5), S(27, 8) } // Bishops + { 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 a outpost square in one move, bigger if outpost square is supported by a pawn. + // 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(31, 8) }, // Knights - { S( 8, 2), S(13, 4) } // Bishops + { S(21, 5), S(35, 8) }, // Knights + { S( 8, 0), S(14, 4) } // Bishops }; - // Threat[minor/rook][attacked PieceType] contains + // 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[2][PIECE_TYPE_NB] = { - { S(0, 0), S(0, 32), S(25, 39), S(28, 44), S(42, 98), S(35,105) }, // Minor attacks - { S(0, 0), S(0, 27), S(26, 57), S(26, 57), S( 0, 30), S(23, 51) } // Rook attacks + // Attacks on lesser pieces which are pawn-defended are not considered. + const Score Threat[][PIECE_TYPE_NB] = { + { 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 a pawn. - const Score ThreatenedByPawn[PIECE_TYPE_NB] = { - S(0, 0), S(0, 0), S(107, 138), S(84, 122), S(114, 203), S(121, 217) - }; + // 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. + // 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(0), V( 1), V(34), V(90), V(214), V(328) }, - { V(7), V(14), V(37), V(63), V(134), V(189) } + { V(5), V( 5), V(31), V(73), V(166), V(252) }, + { V(7), V(14), V(38), V(73), V(166), V(252) } }; - // PassedFile[File] contains a bonus according to the file of a passed pawn. - const Score PassedFile[] = { - S( 12, 10), S( 3, 10), S( 1, -8), S(-27, -12), - S(-27, -12), S( 1, -8), S( 3, 10), S( 12, 10) + // 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 ThreatenedByHangingPawn = S(40, 60); - // Assorted bonuses and penalties used by evaluation - const Score KingOnOne = S( 2, 58); - const Score KingOnMany = S( 6,125); - const Score RookOnPawn = S( 7, 27); - const Score RookOnOpenFile = S(43, 21); - const Score RookOnSemiOpenFile = S(19, 10); - const Score BishopPawns = S( 8, 12); - const Score MinorBehindPawn = S(16, 0); - const Score TrappedRook = S(92, 0); - const Score Unstoppable = S( 0, 20); - const Score Hanging = S(31, 26); - const Score PawnAttackThreat = S(20, 20); - const Score Checked = S(20, 20); + 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 @@ -211,52 +206,44 @@ namespace { #undef S #undef V - // SpaceMask[Color] contains the area of the board which is considered - // by the space evaluation. In the middlegame, each side is given a bonus - // based on how many squares inside this area are safe and available for - // friendly minor pieces. - const Bitboard SpaceMask[COLOR_NB] = { - (FileCBB | FileDBB | FileEBB | FileFBB) & (Rank2BB | Rank3BB | Rank4BB), - (FileCBB | FileDBB | FileEBB | FileFBB) & (Rank7BB | Rank6BB | Rank5BB) - }; - // 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[]. - Score KingDanger[512]; + Score KingDanger[400]; // KingAttackWeights[PieceType] contains king attack weights by piece type const int KingAttackWeights[PIECE_TYPE_NB] = { 0, 0, 7, 5, 4, 1 }; // Penalties for enemy's safe checks const int QueenContactCheck = 89; - const int QueenCheck = 50; - const int RookCheck = 45; - const int BishopCheck = 6; - const int KnightCheck = 14; + 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 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.square(Them)); + 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.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 @@ -264,17 +251,20 @@ namespace { } - // evaluate_pieces() assigns bonuses and penalties to the pieces of a given color - - template - Score evaluate_pieces(const Position& pos, EvalInfo& ei, Score* mobility, const Bitboard* mobilityArea) { + // 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, + 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 Bitboard OutpostRanks = (Us == WHITE ? Rank4BB | Rank5BB | Rank6BB + : Rank5BB | Rank4BB | Rank3BB); const Square* pl = pos.squares(Us); ei.attackedBy[Us][Pt] = 0; @@ -289,15 +279,14 @@ namespace { if (ei.pinnedPieces[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]; - 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) @@ -305,14 +294,14 @@ namespace { | ei.attackedBy[Them][BISHOP] | ei.attackedBy[Them][ROOK]); - int mob = popcount(b & mobilityArea[Us]); + int mob = popcount(b & mobilityArea[Us]); mobility[Us] += MobilityBonus[Pt][mob]; if (Pt == BISHOP || Pt == KNIGHT) { // Bonus for outpost squares - bb = OutpostMask[Us] & ~ei.pi->pawn_attacks_span(Them); + bb = OutpostRanks & ~ei.pi->pawn_attacks_span(Them); if (bb & s) score += Outpost[Pt == BISHOP][!!(ei.attackedBy[Us][PAWN] & s)]; else @@ -327,7 +316,7 @@ namespace { && (pos.pieces(PAWN) & (s + pawn_push(Us)))) score += MinorBehindPawn; - // Penalty for pawns on same color square of bishop + // 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); @@ -350,18 +339,14 @@ namespace { { // Bonus for aligning with enemy pawns on the same rank/file if (relative_rank(Us, s) >= RANK_5) - { - Bitboard alignedPawns = pos.pieces(Them, PAWN) & PseudoAttacks[ROOK][s]; - if (alignedPawns) - score += popcount(alignedPawns) * RookOnPawn; - } + score += RookOnPawn * popcount(pos.pieces(Them, PAWN) & PseudoAttacks[ROOK][s]); // Bonus when on an open or semi-open file if (ei.pi->semiopen_file(Us, file_of(s))) - score += ei.pi->semiopen_file(Them, file_of(s)) ? RookOnOpenFile : RookOnSemiOpenFile; + score += RookOnFile[!!ei.pi->semiopen_file(Them, file_of(s))]; - // Penalize when trapped by the king, even more if king cannot castle - if (mob <= 3 && !ei.pi->semiopen_file(Us, file_of(s))) + // Penalize when trapped by the king, even more if the king cannot castle + else if (mob <= 3) { Square ksq = pos.square(Us); @@ -371,29 +356,50 @@ namespace { score -= (TrappedRook - make_score(mob * 22, 0)) * (1 + !pos.can_castle(Us)); } } + + if (Pt == QUEEN) + { + // Penalty if any relative pin or discovered attack against the queen + if (pos.slider_blockers(pos.pieces(Them, ROOK, BISHOP), s)) + score -= WeakQueen; + } } if (DoTrace) Trace::add(Pt, Us, score); - // Recursively call evaluate_pieces() of next piece type until KING excluded - 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*, const Bitboard*) { return SCORE_ZERO; } + Score evaluate_pieces(const Position&, EvalInfo&, Score*, const Bitboard*) { return SCORE_ZERO; } template<> - Score evaluate_pieces(const Position&, EvalInfo&, Score*, const 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 + 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.square(Us); @@ -403,13 +409,14 @@ 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 into the KingDanger[] array. The initial value is based on the @@ -418,68 +425,79 @@ namespace { // the pawn shelter (current 'score' value). attackUnits = std::min(72, ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them]) + 9 * ei.kingAdjacentZoneAttacksCount[Them] - + 27 * popcount(undefended) - + 11 * !!ei.pinnedPieces[Us] + + 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 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] - | ei.attackedBy[Them][KING]; - if (b) - attackUnits += QueenContactCheck * popcount(b); - } + // ...and keep squares supported by another enemy piece + attackUnits += QueenContactCheck * popcount(b & ei.attackedBy2[Them]); - // Analyse the enemy's safe distance checks for sliders and knights - safe = ~(ei.attackedBy[Us][ALL_PIECES] | pos.pieces(Them)); + // Analyse the safe enemy's checks which are possible on next move... + safe = ~(ei.attackedBy[Us][ALL_PIECES] | pos.pieces(Them)); - b1 = pos.attacks_from(ksq) & safe; - b2 = pos.attacks_from(ksq) & safe; + // ... 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); + b2 = pos.attacks_from(ksq); // Enemy queen safe checks - b = (b1 | b2) & ei.attackedBy[Them][QUEEN]; - if (b) - { - attackUnits += QueenCheck * popcount(b); - score -= Checked; - } + 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); - score -= Checked; - } + // 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); - score -= Checked; - } + // 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); - score -= Checked; - } + 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; + + // 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. + // array and subtract the score from the evaluation. score -= KingDanger[std::max(std::min(attackUnits, 399), 0)]; } + // 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); @@ -487,8 +505,8 @@ namespace { } - // 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 Score evaluate_threats(const Position& pos, const EvalInfo& ei) { @@ -505,6 +523,11 @@ namespace { Bitboard b, weak, defended, safeThreats; Score score = SCORE_ZERO; + // 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]; @@ -516,10 +539,10 @@ namespace { safeThreats = (shift_bb(b) | shift_bb(b)) & weak; if (weak ^ safeThreats) - score += ThreatenedByHangingPawn; + score += ThreatByHangingPawn; while (safeThreats) - score += ThreatenedByPawn[type_of(pos.piece_on(pop_lsb(&safeThreats)))]; + score += ThreatBySafePawn[type_of(pos.piece_on(pop_lsb(&safeThreats)))]; } // Non-pawn enemies defended by a pawn @@ -541,13 +564,11 @@ namespace { while (b) score += Threat[Rook ][type_of(pos.piece_on(pop_lsb(&b)))]; - b = weak & ~ei.attackedBy[Them][ALL_PIECES]; - if (b) - score += Hanging * popcount(b); + score += Hanging * popcount(weak & ~ei.attackedBy[Them][ALL_PIECES]); b = weak & ei.attackedBy[Us][KING]; if (b) - score += more_than_one(b) ? KingOnMany : KingOnOne; + score += ThreatByKing[more_than_one(b)]; } // Bonus if some pawns can safely push and attack an enemy piece @@ -562,8 +583,7 @@ namespace { & pos.pieces(Them) & ~ei.attackedBy[Us][PAWN]; - if (b) - score += popcount(b) * PawnAttackThreat; + score += ThreatByPawnPush * popcount(b); if (DoTrace) Trace::add(THREAT, Us, score); @@ -589,6 +609,7 @@ namespace { Square s = pop_lsb(&b); assert(pos.pawn_passed(Us, s)); + assert(!(pos.pieces(PAWN) & forward_bb(Us, s))); int r = relative_rank(Us, s) - RANK_2; int rr = r * (r - 1); @@ -627,7 +648,7 @@ namespace { // assign a smaller bonus if the block square isn't attacked. int k = !unsafeSquares ? 18 : !(unsafeSquares & blockSq) ? 8 : 0; - // If the path to queen is fully defended, assign a big bonus. + // 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; @@ -638,20 +659,17 @@ namespace { mbonus += k * rr, ebonus += k * rr; } else if (pos.pieces(Us) & blockSq) - mbonus += rr * 3 + r * 2 + 3, ebonus += rr + r * 2; + mbonus += rr + r * 2, ebonus += rr + r * 2; } // rr != 0 - if (pos.count(Us) < pos.count(Them)) - ebonus += ebonus / 4; - score += make_score(mbonus, ebonus) + PassedFile[file_of(s)]; } if (DoTrace) - Trace::add(PASSED, Us, score * Weights[PassedPawns]); + Trace::add(PASSED, Us, score); // Add the scores to the middlegame and endgame eval - return score * Weights[PassedPawns]; + return score; } @@ -665,11 +683,14 @@ namespace { 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]); @@ -683,24 +704,25 @@ namespace { assert(unsigned(safe >> (Us == WHITE ? 32 : 0)) == 0); // ...count safe + (behind & safe) with a single popcount - int bonus = popcount((Us == WHITE ? safe << 32 : safe >> 32) | (behind & safe)); - int weight = pos.count(Us) + pos.count(Us) - + pos.count(Them) + pos.count(Them); + int bonus = popcount((Us == WHITE ? safe << 32 : safe >> 32) | (behind & safe)); + bonus = std::min(16, bonus); + int weight = pos.count(Us) - 2 * ei.pi->open_files(); - return make_score(bonus * weight * weight, 0); + return make_score(bonus * weight * weight / 18, 0); } // evaluate_initiative() computes the initiative correction value for the - // position, i.e. second order bonus/malus based on the known attacking/defending + // 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) { - int kingDistance = distance(pos.square(WHITE), pos.square(BLACK)); + int kingDistance = distance(pos.square(WHITE), pos.square(BLACK)) + - distance(pos.square(WHITE), pos.square(BLACK)); int pawns = pos.count(WHITE) + pos.count(BLACK); // Compute the initiative bonus for the attacking side - int initiative = 8 * (pawns + asymmetry + kingDistance - 15); + int initiative = 8 * (asymmetry + kingDistance - 15) + 12 * pawns; // 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 @@ -710,61 +732,98 @@ namespace { return make_score(0, value); } + + // evaluate_scale_factor() computes the scale factor for the winning side + ScaleFactor evaluate_scale_factor(const Position& pos, const EvalInfo& ei, Value eg) { + + Color strongSide = eg > VALUE_DRAW ? WHITE : BLACK; + ScaleFactor sf = ei.me->scale_factor(pos, strongSide); + + // If we don't already have an unusual scale factor, check for certain + // types of endgames, and use a lower scale for those. + if ( ei.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); + + // 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)); + } + + return sf; + } + } // namespace /// 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. +/// of the position from the point of view of the side to move. template Value Eval::evaluate(const Position& pos) { assert(!pos.checkers()); + Score mobility[COLOR_NB] = { SCORE_ZERO, SCORE_ZERO }; EvalInfo ei; - Score score, mobility[2] = { SCORE_ZERO, SCORE_ZERO }; - - // Initialize score by reading the incrementally updated scores included - // in the position object (material + piece square tables). - // Score is computed from the point of view of white. - score = pos.psq_score(); // Probe the material hash table - Material::Entry* me = Material::probe(pos); - score += me->imbalance(); + ei.me = Material::probe(pos); // If we have a specialized evaluation function for the current material // configuration, call it and return. - if (me->specialized_eval_exists()) - return me->evaluate(pos); + if (ei.me->specialized_eval_exists()) + return ei.me->evaluate(pos); + + // Initialize score by reading the incrementally updated scores included in + // the position object (material + piece square tables) and the material + // imbalance. Score is computed internally from the white point of view. + Score score = pos.psq_score() + ei.me->imbalance(); // Probe the pawn hash table ei.pi = Pawns::probe(pos); - score += ei.pi->pawns_score() * Weights[PawnStructure]; + score += ei.pi->pawns_score(); // Initialize attack and king safety bitboards ei.attackedBy[WHITE][ALL_PIECES] = ei.attackedBy[BLACK][ALL_PIECES] = 0; - init_eval_info(pos, ei); - init_eval_info(pos, ei); + 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 + // 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) }; - // Do not include in mobility squares protected by enemy pawns, or occupied + // 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)) }; - // Evaluate pieces and mobility - score += evaluate_pieces(pos, ei, mobility, mobilityArea); - score += (mobility[WHITE] - mobility[BLACK]) * Weights[Mobility]; + // Evaluate all pieces but king and pawns + score += evaluate_pieces(pos, ei, mobility, mobilityArea); + score += mobility[WHITE] - mobility[BLACK]; - // Evaluate kings after all other pieces because we need complete attack + // 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); @@ -782,65 +841,38 @@ Value Eval::evaluate(const Position& pos) { { Bitboard b; if ((b = ei.pi->passed_pawns(WHITE)) != 0) - score += int(relative_rank(WHITE, frontmost_sq(WHITE, b))) * Unstoppable; + score += Unstoppable * int(relative_rank(WHITE, frontmost_sq(WHITE, b))); if ((b = ei.pi->passed_pawns(BLACK)) != 0) - score -= int(relative_rank(BLACK, frontmost_sq(BLACK, b))) * Unstoppable; + score -= Unstoppable * int(relative_rank(BLACK, frontmost_sq(BLACK, b))); } // 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)) * Weights[Space]; + score += evaluate_space(pos, ei) + - evaluate_space(pos, ei); // Evaluate position potential for the winning side score += evaluate_initiative(pos, ei.pi->pawn_asymmetry(), eg_value(score)); - // Scale winning side if position is more drawish than it appears - Color strongSide = eg_value(score) > VALUE_DRAW ? WHITE : BLACK; - ScaleFactor sf = me->scale_factor(pos, strongSide); - - // If we don't already have an unusual scale factor, check for certain - // types of endgames, and use a lower scale for those. - if ( 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 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); - - // 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 * sf / SCALE_FACTOR_NORMAL); - } - // Endings where weaker side can place his king in front of the opponent's - // pawns are drawish. - else if ( abs(eg_value(score)) <= BishopValueEg - && ei.pi->pawn_span(strongSide) <= 1 - && !pos.pawn_passed(~strongSide, pos.square(~strongSide))) - sf = ei.pi->pawn_span(strongSide) ? ScaleFactor(51) : ScaleFactor(37); - } + // Evaluate scale factor for the winning side + ScaleFactor sf = evaluate_scale_factor(pos, ei, eg_value(score)); // Interpolate between a middlegame and a (scaled by 'sf') endgame score - Value v = mg_value(score) * int(me->game_phase()) - + eg_value(score) * int(PHASE_MIDGAME - me->game_phase()) * sf / SCALE_FACTOR_NORMAL; + Value v = mg_value(score) * int(ei.me->game_phase()) + + eg_value(score) * int(PHASE_MIDGAME - ei.me->game_phase()) * sf / SCALE_FACTOR_NORMAL; v /= int(PHASE_MIDGAME); - // In case of tracing add all single evaluation terms + // In case of tracing add all remaining individual evaluation terms if (DoTrace) { Trace::add(MATERIAL, pos.psq_score()); - Trace::add(IMBALANCE, me->imbalance()); + Trace::add(IMBALANCE, ei.me->imbalance()); Trace::add(PAWN, ei.pi->pawns_score()); - Trace::add(MOBILITY, mobility[WHITE] * Weights[Mobility] - , mobility[BLACK] * Weights[Mobility]); - Trace::add(SPACE, evaluate_space(pos, ei) * Weights[Space] - , evaluate_space(pos, ei) * Weights[Space]); + Trace::add(MOBILITY, mobility[WHITE], mobility[BLACK]); + Trace::add(SPACE, evaluate_space(pos, ei) + , evaluate_space(pos, ei)); Trace::add(TOTAL, score); } @@ -893,13 +925,13 @@ std::string Eval::trace(const Position& pos) { void Eval::init() { - const int MaxSlope = 8700; - const int Peak = 1280000; + const int MaxSlope = 322; + const int Peak = 47410; int t = 0; for (int i = 0; i < 400; ++i) { - t = std::min(Peak, std::min(i * i * 27, t + MaxSlope)); - KingDanger[i] = make_score(t / 1000, 0) * Weights[KingSafety]; + t = std::min(Peak, std::min(i * i - 16, t + MaxSlope)); + KingDanger[i] = make_score(t * 268 / 7700, 0); } }