X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fendgame.cpp;h=f82beef608e2a1772d0ce472847c62754edcead6;hp=f01f75a0171ff2df2b41f888e489531b5d65aef0;hb=683595fee15a1d8ceeb1bbd577d96ed9c0f8aaaa;hpb=039badfda8fa05bc466612bce996837c7d69f22b diff --git a/src/endgame.cpp b/src/endgame.cpp index f01f75a0..f82beef6 100644 --- a/src/endgame.cpp +++ b/src/endgame.cpp @@ -51,41 +51,16 @@ EvaluationFunction EvaluateKBBKN(WHITE), EvaluateKNKBB(BLACK); // KBB vs /// Scaling functions -// KBP vs K -KBPKScalingFunction ScaleKBPK = KBPKScalingFunction(WHITE); -KBPKScalingFunction ScaleKKBP = KBPKScalingFunction(BLACK); - -// KQ vs KRP -KQKRPScalingFunction ScaleKQKRP = KQKRPScalingFunction(WHITE); -KQKRPScalingFunction ScaleKRPKQ = KQKRPScalingFunction(BLACK); - -// KRP vs KR -KRPKRScalingFunction ScaleKRPKR = KRPKRScalingFunction(WHITE); -KRPKRScalingFunction ScaleKRKRP = KRPKRScalingFunction(BLACK); - -// KRPP vs KRP -KRPPKRPScalingFunction ScaleKRPPKRP = KRPPKRPScalingFunction(WHITE); -KRPPKRPScalingFunction ScaleKRPKRPP = KRPPKRPScalingFunction(BLACK); - -// King and pawns vs king -KPsKScalingFunction ScaleKPsK = KPsKScalingFunction(WHITE); -KPsKScalingFunction ScaleKKPs = KPsKScalingFunction(BLACK); - -// KBP vs KB -KBPKBScalingFunction ScaleKBPKB = KBPKBScalingFunction(WHITE); -KBPKBScalingFunction ScaleKBKBP = KBPKBScalingFunction(BLACK); - -// KBP vs KN -KBPKNScalingFunction ScaleKBPKN = KBPKNScalingFunction(WHITE); -KBPKNScalingFunction ScaleKNKBP = KBPKNScalingFunction(BLACK); - -// KNP vs K -KNPKScalingFunction ScaleKNPK = KNPKScalingFunction(WHITE); -KNPKScalingFunction ScaleKKNP = KNPKScalingFunction(BLACK); - -// KPKP -KPKPScalingFunction ScaleKPKPw = KPKPScalingFunction(WHITE); -KPKPScalingFunction ScaleKPKPb = KPKPScalingFunction(BLACK); +ScalingFunction ScaleKBPK(WHITE), ScaleKKBP(BLACK); // KBP vs K +ScalingFunction ScaleKQKRP(WHITE), ScaleKRPKQ(BLACK); // KQ vs KRP +ScalingFunction ScaleKRPKR(WHITE), ScaleKRKRP(BLACK); // KRP vs KR +ScalingFunction ScaleKRPPKRP(WHITE), ScaleKRPKRPP(BLACK); // KRPP vs KRP +ScalingFunction ScaleKPsK(WHITE), ScaleKKPs(BLACK); // King and pawns vs king +ScalingFunction ScaleKBPKB(WHITE), ScaleKBKBP(BLACK); // KBP vs KB +ScalingFunction ScaleKBPPKB(WHITE), ScaleKBKBPP(BLACK); // KBPP vs KB +ScalingFunction ScaleKBPKN(WHITE), ScaleKNKBP(BLACK); // KBP vs KN +ScalingFunction ScaleKNPK(WHITE), ScaleKKNP(BLACK); // KNP vs K +ScalingFunction ScaleKPKPw(WHITE), ScaleKPKPb(BLACK); // KPKP //// @@ -158,27 +133,6 @@ namespace { //// Functions //// -/// Constructors - -EndgameEvaluationFunction::EndgameEvaluationFunction(Color c) : strongerSide(c) { - weakerSide = opposite_color(strongerSide); -} - -ScalingFunction::ScalingFunction(Color c) : strongerSide(c) { - weakerSide = opposite_color(c); -} - -KBPKScalingFunction::KBPKScalingFunction(Color c) : ScalingFunction(c) {} -KQKRPScalingFunction::KQKRPScalingFunction(Color c) : ScalingFunction(c) {} -KRPKRScalingFunction::KRPKRScalingFunction(Color c) : ScalingFunction(c) {} -KRPPKRPScalingFunction::KRPPKRPScalingFunction(Color c) : ScalingFunction(c) {} -KPsKScalingFunction::KPsKScalingFunction(Color c) : ScalingFunction(c) {} -KBPKBScalingFunction::KBPKBScalingFunction(Color c) : ScalingFunction(c) {} -KBPKNScalingFunction::KBPKNScalingFunction(Color c) : ScalingFunction(c) {} -KNPKScalingFunction::KNPKScalingFunction(Color c) : ScalingFunction(c) {} -KPKPScalingFunction::KPKPScalingFunction(Color c) : ScalingFunction(c) {} - - /// Mate with KX vs K. This function is used to evaluate positions with /// King and plenty of material vs a lone king. It simply gives the /// attacking side a bonus for driving the defending king towards the edge @@ -429,7 +383,7 @@ Value EvaluationFunction::apply(const Position& pos) { } template<> -Value EvaluationFunction::apply(const Position &pos) { +Value EvaluationFunction::apply(const Position&) { return Value(0); } @@ -439,8 +393,8 @@ Value EvaluationFunction::apply(const Position &pos) { /// bishop of the wrong color. If such a draw is detected, ScaleFactor(0) is /// returned. If not, the return value is SCALE_FACTOR_NONE, i.e. no scaling /// will be used. - -ScaleFactor KBPKScalingFunction::apply(const Position& pos) { +template<> +ScaleFactor ScalingFunction::apply(const Position& pos) { assert(pos.non_pawn_material(strongerSide) == BishopValueMidgame); assert(pos.piece_count(strongerSide, BISHOP) == 1); @@ -494,8 +448,8 @@ ScaleFactor KBPKScalingFunction::apply(const Position& pos) { /// king and queen, while the weaker side has at least a rook and a pawn. /// It tests for fortress draws with a rook on the third rank defended by /// a pawn. - -ScaleFactor KQKRPScalingFunction::apply(const Position& pos) { +template<> +ScaleFactor ScalingFunction::apply(const Position& pos) { assert(pos.non_pawn_material(strongerSide) == QueenValueMidgame); assert(pos.piece_count(strongerSide, QUEEN) == 1); @@ -525,8 +479,8 @@ ScaleFactor KQKRPScalingFunction::apply(const Position& pos) { /// /// It would also be nice to rewrite the actual code for this function, /// which is mostly copied from Glaurung 1.x, and not very pretty. - -ScaleFactor KRPKRScalingFunction::apply(const Position &pos) { +template<> +ScaleFactor ScalingFunction::apply(const Position &pos) { assert(pos.non_pawn_material(strongerSide) == RookValueMidgame); assert(pos.piece_count(strongerSide, PAWN) == 1); @@ -643,8 +597,8 @@ ScaleFactor KRPKRScalingFunction::apply(const Position &pos) { /// KRPPKRPScalingFunction scales KRPP vs KRP endgames. There is only a /// single pattern: If the stronger side has no pawns and the defending king /// is actively placed, the position is drawish. - -ScaleFactor KRPPKRPScalingFunction::apply(const Position &pos) { +template<> +ScaleFactor ScalingFunction::apply(const Position &pos) { assert(pos.non_pawn_material(strongerSide) == RookValueMidgame); assert(pos.piece_count(strongerSide, PAWN) == 2); @@ -682,8 +636,8 @@ ScaleFactor KRPPKRPScalingFunction::apply(const Position &pos) { /// KPsKScalingFunction scales endgames with king and two or more pawns /// against king. There is just a single rule here: If all pawns are on /// the same rook file and are blocked by the defending king, it's a draw. - -ScaleFactor KPsKScalingFunction::apply(const Position &pos) { +template<> +ScaleFactor ScalingFunction::apply(const Position &pos) { assert(pos.non_pawn_material(strongerSide) == Value(0)); assert(pos.piece_count(strongerSide, PAWN) >= 2); @@ -728,8 +682,8 @@ ScaleFactor KPsKScalingFunction::apply(const Position &pos) { /// square of the king is not of the same color as the stronger side's bishop, /// it's a draw. If the two bishops have opposite color, it's almost always /// a draw. - -ScaleFactor KBPKBScalingFunction::apply(const Position &pos) { +template<> +ScaleFactor ScalingFunction::apply(const Position &pos) { assert(pos.non_pawn_material(strongerSide) == BishopValueMidgame); assert(pos.piece_count(strongerSide, BISHOP) == 1); @@ -779,12 +733,86 @@ ScaleFactor KBPKBScalingFunction::apply(const Position &pos) { } +/// KBPPKBScalingFunction scales KBPP vs KB endgames. It detects a few basic +/// draws with opposite-colored bishops. +template<> +ScaleFactor ScalingFunction::apply(const Position& pos) { + + assert(pos.non_pawn_material(strongerSide) == BishopValueMidgame); + assert(pos.piece_count(strongerSide, BISHOP) == 1); + assert(pos.piece_count(strongerSide, PAWN) == 2); + assert(pos.non_pawn_material(weakerSide) == BishopValueMidgame); + assert(pos.piece_count(weakerSide, BISHOP) == 1); + assert(pos.piece_count(weakerSide, PAWN) == 0); + + Square wbsq = pos.piece_list(strongerSide, BISHOP, 0); + Square bbsq = pos.piece_list(weakerSide, BISHOP, 0); + + if (square_color(wbsq) == square_color(bbsq)) + // Not opposite-colored bishops, no scaling + return SCALE_FACTOR_NONE; + + Square ksq = pos.king_square(weakerSide); + Square psq1 = pos.piece_list(strongerSide, PAWN, 0); + Square psq2 = pos.piece_list(strongerSide, PAWN, 1); + Rank r1 = square_rank(psq1); + Rank r2 = square_rank(psq2); + Square blockSq1, blockSq2; + + if (relative_rank(strongerSide, psq1) > relative_rank(strongerSide, psq2)) + { + blockSq1 = psq1 + pawn_push(strongerSide); + blockSq2 = make_square(square_file(psq2), square_rank(psq1)); + } + else + { + blockSq1 = psq2 + pawn_push(strongerSide); + blockSq2 = make_square(square_file(psq1), square_rank(psq2)); + } + + switch (file_distance(psq1, psq2)) + { + case 0: + // Both pawns are on the same file. Easy draw if defender firmly controls + // some square in the frontmost pawn's path. + if ( square_file(ksq) == square_file(blockSq1) + && relative_rank(strongerSide, ksq) >= relative_rank(strongerSide, blockSq1) + && square_color(ksq) != square_color(wbsq)) + return ScaleFactor(0); + else + return SCALE_FACTOR_NONE; + + case 1: + // Pawns on neighboring files. Draw if defender firmly controls the square + // in front of the frontmost pawn's path, and the square diagonally behind + // this square on the file of the other pawn. + if ( ksq == blockSq1 + && square_color(ksq) != square_color(wbsq) + && ( bbsq == blockSq2 + || (pos.piece_attacks(blockSq2) & pos.bishops(weakerSide)) + || rank_distance(r1, r2) >= 2)) + return ScaleFactor(0); + else if ( ksq == blockSq2 + && square_color(ksq) != square_color(wbsq) + && ( bbsq == blockSq1 + || (pos.piece_attacks(blockSq1) & pos.bishops(weakerSide)))) + return ScaleFactor(0); + else + return SCALE_FACTOR_NONE; + + default: + // The pawns are not on the same file or adjacent files. No scaling. + return SCALE_FACTOR_NONE; + } +} + + /// KBPKNScalingFunction scales KBP vs KN endgames. There is a single rule: /// If the defending king is somewhere along the path of the pawn, and the /// square of the king is not of the same color as the stronger side's bishop, /// it's a draw. - -ScaleFactor KBPKNScalingFunction::apply(const Position &pos) { +template<> +ScaleFactor ScalingFunction::apply(const Position &pos) { assert(pos.non_pawn_material(strongerSide) == BishopValueMidgame); assert(pos.piece_count(strongerSide, BISHOP) == 1); @@ -810,8 +838,8 @@ ScaleFactor KBPKNScalingFunction::apply(const Position &pos) { /// KNPKScalingFunction scales KNP vs K endgames. There is a single rule: /// If the pawn is a rook pawn on the 7th rank and the defending king prevents /// the pawn from advancing, the position is drawn. - -ScaleFactor KNPKScalingFunction::apply(const Position &pos) { +template<> +ScaleFactor ScalingFunction::apply(const Position &pos) { assert(pos.non_pawn_material(strongerSide) == KnightValueMidgame); assert(pos.piece_count(strongerSide, KNIGHT) == 1); @@ -840,8 +868,8 @@ ScaleFactor KNPKScalingFunction::apply(const Position &pos) { /// the pawn as well. The exception is when the stronger side's pawn is far /// advanced and not on a rook file; in this case it is often possible to win /// (e.g. 8/4k3/3p4/3P4/6K1/8/8/8 w - - 0 1). - -ScaleFactor KPKPScalingFunction::apply(const Position &pos) { +template<> +ScaleFactor ScalingFunction::apply(const Position &pos) { assert(pos.non_pawn_material(strongerSide) == Value(0)); assert(pos.non_pawn_material(weakerSide) == Value(0));