X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fevaluate.cpp;h=12329fcdceef82a7872aa2f43af3c8dfd1344e2f;hp=3f95f0d32a253598e57073721efa2df70f1df67c;hb=d11426c7779b45a5f91f260ecb9e0c4c1e964e2b;hpb=2e3faae067e31d79f9157074c9e37f4631b8d59f diff --git a/src/evaluate.cpp b/src/evaluate.cpp index 3f95f0d3..12329fcd 100644 --- a/src/evaluate.cpp +++ b/src/evaluate.cpp @@ -1,13 +1,14 @@ /* - Glaurung, a UCI chess playing engine. - Copyright (C) 2004-2008 Tord Romstad + Stockfish, a UCI chess playing engine derived from Glaurung 2.1 + Copyright (C) 2004-2008 Tord Romstad (Glaurung author) + Copyright (C) 2008 Marco Costalba - Glaurung is free software: you can redistribute it and/or modify + Stockfish is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. - Glaurung is distributed in the hope that it will be useful, + Stockfish is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. @@ -51,6 +52,7 @@ namespace { int WeightPassedPawnsMidgame = 0x100; int WeightPassedPawnsEndgame = 0x100; int WeightKingSafety[2] = { 0x100, 0x100 }; + int WeightSpace; // Internal evaluation weights. These are applied on top of the evaluation // weights read from UCI parameters. The purpose is to be able to change @@ -62,8 +64,9 @@ namespace { const int WeightPawnStructureEndgameInternal = 0x100; const int WeightPassedPawnsMidgameInternal = 0x100; const int WeightPassedPawnsEndgameInternal = 0x100; - const int WeightKingSafetyInternal = 0x100; - const int WeightKingOppSafetyInternal = 0x100; + const int WeightKingSafetyInternal = 0x110; + const int WeightKingOppSafetyInternal = 0x110; + const int WeightSpaceInternal = 0x30; // Visually better to define tables constants typedef Value V; @@ -202,6 +205,19 @@ namespace { ((1ULL << SQ_A8) | (1ULL << SQ_H8)) }; + // The SpaceMask[color] contains area of the board which is consdered 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<eg_value(), WeightPawnStructureEndgame); // Initialize king attack bitboards and king attack zones for both sides - ei.attackedBy[WHITE][KING] = pos.king_attacks(pos.king_square(WHITE)); - ei.attackedBy[BLACK][KING] = pos.king_attacks(pos.king_square(BLACK)); + ei.attackedBy[WHITE][KING] = pos.piece_attacks(pos.king_square(WHITE)); + ei.attackedBy[BLACK][KING] = pos.piece_attacks(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); @@ -337,20 +353,20 @@ Value evaluate(const Position &pos, EvalInfo &ei, int threadID) { for (Color c = WHITE; c <= BLACK; c++) { // Knights - for (int i = 0; i < pos.knight_count(c); i++) - evaluate_knight(pos, pos.knight_list(c, i), c, ei); + for (int i = 0; i < pos.piece_count(c, KNIGHT); i++) + evaluate_knight(pos, pos.piece_list(c, KNIGHT, i), c, ei); // Bishops - for (int i = 0; i < pos.bishop_count(c); i++) - evaluate_bishop(pos, pos.bishop_list(c, i), c, ei); + for (int i = 0; i < pos.piece_count(c, BISHOP); i++) + evaluate_bishop(pos, pos.piece_list(c, BISHOP, i), c, ei); // Rooks - for (int i = 0; i < pos.rook_count(c); i++) - evaluate_rook(pos, pos.rook_list(c, i), c, ei); + for (int i = 0; i < pos.piece_count(c, ROOK); i++) + evaluate_rook(pos, pos.piece_list(c, ROOK, i), c, ei); // Queens - for(int i = 0; i < pos.queen_count(c); i++) - evaluate_queen(pos, pos.queen_list(c, i), c, ei); + for(int i = 0; i < pos.piece_count(c, QUEEN); i++) + evaluate_queen(pos, pos.piece_list(c, QUEEN, i), c, ei); // Special pattern: trapped bishops on a7/h7/a2/h2 Bitboard b = pos.bishops(c) & MaskA7H7[c]; @@ -406,6 +422,13 @@ Value evaluate(const Position &pos, EvalInfo &ei, int threadID) { ei.mgValue += ei.pi->kingside_storm_value(WHITE) - ei.pi->queenside_storm_value(BLACK); + + // Evaluate space for both sides + if (ei.mi->space_weight() > 0) + { + evaluate_space(pos, WHITE, ei); + evaluate_space(pos, BLACK, ei); + } } // Mobility @@ -413,7 +436,7 @@ Value evaluate(const Position &pos, EvalInfo &ei, int threadID) { 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: + // 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)) @@ -427,7 +450,7 @@ Value evaluate(const Position &pos, EvalInfo &ei, int threadID) { { // 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.pawn_count(WHITE) + pos.pawn_count(BLACK) == 1); + bool one_pawn = (pos.piece_count(WHITE, PAWN) + pos.piece_count(BLACK, PAWN) == 1); sf = one_pawn ? ScaleFactor(8) : ScaleFactor(32); } else @@ -526,6 +549,7 @@ void read_weights(Color us) { WeightKingSafety[us] = weight_option("Cowardice", WeightKingSafetyInternal); WeightKingSafety[them] = weight_option("Aggressiveness", WeightKingOppSafetyInternal); + WeightSpace = weight_option("Space", WeightSpaceInternal); init_safety(); } @@ -569,7 +593,7 @@ namespace { if (v && (p.pawn_attacks(them, s) & p.pawns(us))) { bonus += v / 2; - if ( p.knight_count(them) == 0 + if ( p.piece_count(them, KNIGHT) == 0 && (SquaresByColorBB[square_color(s)] & p.bishops(them)) == EmptyBoardBB) bonus += v; } @@ -584,7 +608,7 @@ namespace { void evaluate_knight(const Position &p, Square s, Color us, EvalInfo &ei) { - Bitboard b = p.knight_attacks(s); + Bitboard b = p.piece_attacks(s); ei.attackedBy[us][KNIGHT] |= b; // King attack, mobility and outposts @@ -612,7 +636,6 @@ namespace { void evaluate_rook(const Position &p, Square s, Color us, EvalInfo &ei) { - //Bitboard b = p.rook_attacks(s); Bitboard b = rook_attacks_bb(s, p.occupied_squares() & ~p.rooks_and_queens(us)); ei.attackedBy[us][ROOK] |= b; @@ -679,7 +702,7 @@ namespace { void evaluate_queen(const Position &p, Square s, Color us, EvalInfo &ei) { - Bitboard b = p.queen_attacks(s); + Bitboard b = p.piece_attacks(s); ei.attackedBy[us][QUEEN] |= b; // King attack and mobility @@ -697,6 +720,10 @@ namespace { } } + inline Bitboard shiftRowsDown(const Bitboard& b, int num) { + + return b >> (num << 3); + } // evaluate_king() assigns bonuses and penalties to a king of a given // color on a given square. @@ -705,147 +732,156 @@ namespace { int shelter = 0, sign = Sign[us]; - // King shelter. - if(relative_rank(us, s) <= RANK_4) { - Bitboard pawns = p.pawns(us) & this_and_neighboring_files_bb(s); - Rank r = square_rank(s); - for(int i = 0; i < 3; i++) - shelter += count_1s_8bit(pawns >> ((r+(i+1)*sign) * 8)) * (64>>i); - ei.mgValue += sign * Value(shelter); + // King shelter + if (relative_rank(us, s) <= RANK_4) + { + Bitboard pawns = p.pawns(us) & this_and_neighboring_files_bb(s); + Rank r = square_rank(s); + for (int i = 1; i < 4; i++) + shelter += count_1s_8bit(shiftRowsDown(pawns, r+i*sign)) * (128>>i); + + ei.mgValue += sign * Value(shelter); } // King safety. This is quite complicated, and is almost certainly far // from optimally tuned. Color them = opposite_color(us); - if(p.queen_count(them) >= 1 && ei.kingAttackersCount[them] >= 2 - && p.non_pawn_material(them) >= QueenValueMidgame + RookValueMidgame - && ei.kingAdjacentZoneAttacksCount[them]) { + if ( p.piece_count(them, QUEEN) >= 1 + && ei.kingAttackersCount[them] >= 2 + && p.non_pawn_material(them) >= QueenValueMidgame + RookValueMidgame + && ei.kingAdjacentZoneAttacksCount[them]) + { // Is it the attackers turn to move? bool sente = (them == p.side_to_move()); // Find the attacked squares around the king which has no defenders - // apart from the king itself: + // 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); + 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 = p.occupied_squares(), b, b2; // Initialize the 'attackUnits' variable, which is used later on as an - // index to the SafetyTable[] array. The initial is based on the number - // and types of the attacking pieces, the number of attacked and + // 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 / 32; + 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: + // Analyse safe queen contact checks b = undefended & ei.attacked_by(them, QUEEN) & ~p.pieces_of_color(them); - if(b) { + if (b) + { Bitboard attackedByOthers = - ei.attacked_by(them, PAWN) | ei.attacked_by(them, KNIGHT) - | ei.attacked_by(them, BISHOP) | ei.attacked_by(them, ROOK); + ei.attacked_by(them, PAWN) | ei.attacked_by(them, KNIGHT) + | ei.attacked_by(them, BISHOP) | ei.attacked_by(them, ROOK); + b &= attackedByOthers; - if(b) { + 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); + attackUnits += QueenContactCheckBonus * count * (sente ? 2 : 1); // Is there a mate threat? - if(QueenContactMates && !p.is_check()) { + if (QueenContactMates && !p.is_check()) + { Bitboard escapeSquares = - p.king_attacks(s) & ~p.pieces_of_color(us) & ~attackedByOthers; - while(b) { - Square from, to = pop_1st_bit(&b); - if(!(escapeSquares - & ~queen_attacks_bb(to, occ & clear_mask_bb(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 < p.queen_count(them); i++) { - from = p.queen_list(them, i); - if(bit_is_set(p.queen_attacks(from), to) - && !bit_is_set(p.pinned_pieces(them), from) - && !(rook_attacks_bb(to, occ & clear_mask_bb(from)) - & p.rooks_and_queens(us)) - && !(rook_attacks_bb(to, occ & clear_mask_bb(from)) - & p.rooks_and_queens(us))) - ei.mateThreat[them] = make_move(from, to); + p.piece_attacks(s) & ~p.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 < p.piece_count(them, QUEEN); i++) + { + from = p.piece_list(them, QUEEN, i); + if ( bit_is_set(p.piece_attacks(from), to) + && !bit_is_set(p.pinned_pieces(them), from) + && !(rook_attacks_bb(to, occ & ClearMaskBB[from]) & p.rooks_and_queens(us)) + && !(rook_attacks_bb(to, occ & ClearMaskBB[from]) & p.rooks_and_queens(us))) + + ei.mateThreat[them] = make_move(from, to); + } } - } } } } } - // Analyse safe rook contact checks: - if(RookContactCheckBonus) { - b = undefended & ei.attacked_by(them, ROOK) & ~p.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, QUEEN); - b &= attackedByOthers; - if(b) { - int count = count_1s_max_15(b); - attackUnits += (RookContactCheckBonus * count * (sente? 2 : 1)); - } - } - } - - // Analyse safe distance checks: - if(QueenCheckBonus > 0 || RookCheckBonus > 0) { - b = p.rook_attacks(s) & ~p.pieces_of_color(them) & ~ei.attacked_by(us); + // Analyse safe distance checks + if (QueenCheckBonus > 0 || RookCheckBonus > 0) + { + b = p.piece_attacks(s) & ~p.pieces_of_color(them) & ~ei.attacked_by(us); - // Queen checks - b2 = b & ei.attacked_by(them, QUEEN); - if(b2) attackUnits += QueenCheckBonus * count_1s_max_15(b2); + // Queen checks + b2 = b & ei.attacked_by(them, QUEEN); + if( b2) + attackUnits += QueenCheckBonus * count_1s_max_15(b2); - // Rook checks - b2 = b & ei.attacked_by(them, ROOK); - if(b2) attackUnits += RookCheckBonus * count_1s_max_15(b2); + // Rook checks + b2 = b & ei.attacked_by(them, ROOK); + if (b2) + attackUnits += RookCheckBonus * count_1s_max_15(b2); } - if(QueenCheckBonus > 0 || BishopCheckBonus > 0) { - b = p.bishop_attacks(s) & ~p.pieces_of_color(them) & ~ei.attacked_by(us); - // Queen checks - b2 = b & ei.attacked_by(them, QUEEN); - if(b2) attackUnits += QueenCheckBonus * count_1s_max_15(b2); - - // Bishop checks - b2 = b & ei.attacked_by(them, BISHOP); - if(b2) attackUnits += BishopCheckBonus * count_1s_max_15(b2); + if (QueenCheckBonus > 0 || BishopCheckBonus > 0) + { + b = p.piece_attacks(s) & ~p.pieces_of_color(them) & ~ei.attacked_by(us); + + // Queen checks + b2 = b & ei.attacked_by(them, QUEEN); + if (b2) + attackUnits += QueenCheckBonus * count_1s_max_15(b2); + + // Bishop checks + b2 = b & ei.attacked_by(them, BISHOP); + if (b2) + attackUnits += BishopCheckBonus * count_1s_max_15(b2); } - if(KnightCheckBonus > 0) { - b = p.knight_attacks(s) & ~p.pieces_of_color(them) & ~ei.attacked_by(us); - // Knight checks - b2 = b & ei.attacked_by(them, KNIGHT); - if(b2) attackUnits += KnightCheckBonus * count_1s_max_15(b2); + if (KnightCheckBonus > 0) + { + b = p.piece_attacks(s) & ~p.pieces_of_color(them) & ~ei.attacked_by(us); + + // Knight checks + b2 = b & ei.attacked_by(them, KNIGHT); + if (b2) + attackUnits += KnightCheckBonus * count_1s_max_15(b2); } // Analyse discovered checks (only for non-pawns right now, consider // adding pawns later). - if(DiscoveredCheckBonus) { + if (DiscoveredCheckBonus) + { b = p.discovered_check_candidates(them) & ~p.pawns(); - if(b) - attackUnits += - DiscoveredCheckBonus * count_1s_max_15(b) * (sente? 2 : 1); + if (b) + attackUnits += DiscoveredCheckBonus * count_1s_max_15(b) * (sente? 2 : 1); } // 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; + 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; + 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 @@ -854,9 +890,11 @@ namespace { // 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 * v; - if(us == p.side_to_move()) - ei.futilityMargin += v; + + if (us == p.side_to_move()) + ei.futilityMargin += v; } } @@ -898,6 +936,13 @@ namespace { b2 = squares_in_front_of(us, s); b3 = b2 & ei.attacked_by(them); b4 = b2 & ei.attacked_by(us); + + // If there is an enemy rook or queen attacking the pawn from behind, + // add all X-ray attacks by the rook or queen. + if(bit_is_set(ei.attacked_by(them,ROOK)|ei.attacked_by(them,QUEEN),s) + && squares_behind(us, s) & pos.rooks_and_queens(them)) + b3 = b2; + if((b2 & pos.pieces_of_color(them)) == EmptyBoardBB) { // There are no enemy pieces in the pawn's path! Are any of the // squares in the pawn's path attacked by the enemy? @@ -962,7 +1007,7 @@ namespace { // value if the other side has a rook or queen. if(square_file(s) == FILE_A || square_file(s) == FILE_H) { if(pos.non_pawn_material(them) == KnightValueMidgame - && pos.knight_count(them) == 1) + && pos.piece_count(them, KNIGHT) == 1) ebonus += ebonus / 4; else if(pos.rooks_and_queens(them)) ebonus -= ebonus / 4; @@ -1068,14 +1113,54 @@ namespace { } - // apply_weight applies an evaluation weight to a value. + // evaluate_space() computes the space evaluation for a given side. The + // space evaluation is a simple bonus based on the number of safe squares + // available for minor pieces on the central four files on ranks 2--4. Safe + // squares one, two or three squares behind a friendly pawn are counted + // twice. Finally, the space bonus is scaled by a weight taken from the + // material hash table. + + void evaluate_space(const Position &pos, Color us, EvalInfo &ei) { + + Color them = opposite_color(us); + + // Find the safe squares for our pieces inside the area defined by + // SpaceMask[us]. A square is unsafe it is attacked by an enemy + // pawn, or if it is undefended and attacked by an enemy piece. + + Bitboard safeSquares = + SpaceMask[us] & ~pos.pawns(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.pawns(us); + if(us == WHITE) { + behindFriendlyPawns |= (behindFriendlyPawns >> 8); + behindFriendlyPawns |= (behindFriendlyPawns >> 16); + } + else { + behindFriendlyPawns |= (behindFriendlyPawns << 8); + behindFriendlyPawns |= (behindFriendlyPawns << 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); + } + + + // apply_weight() applies an evaluation weight to a value inline Value apply_weight(Value v, int w) { return (v*w) / 0x100; } - // scale_by_game_phase interpolates between a middle game and an endgame + // 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. @@ -1087,13 +1172,7 @@ namespace { ev = apply_scale_factor(ev, sf[(ev > Value(0) ? WHITE : BLACK)]); - // Linearized sigmoid interpolator - int sph = int(ph); - sph -= (64 - sph) / 4; - sph = Min(PHASE_MIDGAME, Max(PHASE_ENDGAME, sph)); - - Value result = Value(int((mv * sph + ev * (128 - sph)) / 128)); - + Value result = Value(int((mv * ph + ev * (128 - ph)) / 128)); return Value(int(result) & ~(GrainSize - 1)); } @@ -1129,7 +1208,6 @@ namespace { void init_safety() { QueenContactCheckBonus = get_option_value_int("Queen Contact Check Bonus"); - RookContactCheckBonus = get_option_value_int("Rook 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");