X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fendgame.cpp;h=05de131fb2b26deff9336ddc2137db701752d56e;hp=d38247805b50fe87ec6df57cf3cd34b7982e61af;hb=bc3b148d5712ef9ea00e74d3ff5aea10a4d3cabe;hpb=d8f683760c9eb6d2c4714ec83e717dd2143de55c diff --git a/src/endgame.cpp b/src/endgame.cpp index d3824780..05de131f 100644 --- a/src/endgame.cpp +++ b/src/endgame.cpp @@ -2,7 +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) 2015-2017 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + Copyright (C) 2015-2018 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 @@ -31,7 +31,7 @@ namespace { // Table used to drive the king towards the edge of the board // in KX vs K and KQ vs KR endgames. - const int PushToEdges[SQUARE_NB] = { + constexpr int PushToEdges[SQUARE_NB] = { 100, 90, 80, 70, 70, 80, 90, 100, 90, 70, 60, 50, 50, 60, 70, 90, 80, 60, 40, 30, 30, 40, 60, 80, @@ -44,7 +44,7 @@ namespace { // Table used to drive the king towards a corner square of the // right color in KBN vs K endgames. - const int PushToCorners[SQUARE_NB] = { + constexpr int PushToCorners[SQUARE_NB] = { 200, 190, 180, 170, 160, 150, 140, 130, 190, 180, 170, 160, 150, 140, 130, 140, 180, 170, 155, 140, 140, 125, 140, 150, @@ -56,11 +56,11 @@ namespace { }; // Tables used to drive a piece towards or away from another piece - const int PushClose[8] = { 0, 0, 100, 80, 60, 40, 20, 10 }; - const int PushAway [8] = { 0, 5, 20, 40, 60, 80, 90, 100 }; + constexpr int PushClose[8] = { 0, 0, 100, 80, 60, 40, 20, 10 }; + constexpr int PushAway [8] = { 0, 5, 20, 40, 60, 80, 90, 100 }; // Pawn Rank based scaling factors used in KRPPKRP endgame - const int KRPPKRPScaleFactors[RANK_NB] = { 0, 9, 10, 14, 21, 44, 0, 0 }; + constexpr int KRPPKRPScaleFactors[RANK_NB] = { 0, 9, 10, 14, 21, 44, 0, 0 }; #ifndef NDEBUG bool verify_material(const Position& pos, Color c, Value npm, int pawnsCnt) { @@ -86,38 +86,6 @@ namespace { } // namespace -/// Endgames members definitions - -Endgames::Endgames() { - - add("KPK"); - add("KNNK"); - add("KBNK"); - add("KRKP"); - add("KRKB"); - add("KRKN"); - add("KQKP"); - add("KQKR"); - - add("KNPK"); - add("KNPKB"); - add("KRPKR"); - add("KRPKB"); - add("KBPKB"); - add("KBPKN"); - add("KBPPKB"); - add("KRPPKRP"); -} - - -template -void Endgames::add(const string& code) { - StateInfo st; - map()[Position().set(code, WHITE, &st).material_key()] = std::unique_ptr>(new Endgame(WHITE)); - map()[Position().set(code, BLACK, &st).material_key()] = std::unique_ptr>(new Endgame(BLACK)); -} - - /// 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 @@ -143,8 +111,8 @@ Value Endgame::operator()(const Position& pos) const { if ( pos.count(strongSide) || pos.count(strongSide) ||(pos.count(strongSide) && pos.count(strongSide)) - ||(pos.count(strongSide) > 1 && opposite_colors(pos.squares(strongSide)[0], - pos.squares(strongSide)[1]))) + || ( (pos.pieces(strongSide, BISHOP) & ~DarkSquares) + && (pos.pieces(strongSide, BISHOP) & DarkSquares))) result = std::min(result + VALUE_KNOWN_WIN, VALUE_MATE_IN_MAX_PLY - 1); return strongSide == pos.side_to_move() ? result : -result; @@ -222,7 +190,7 @@ Value Endgame::operator()(const Position& pos) const { Value result; // If the stronger side's king is in front of the pawn, it's a win - if (wksq < psq && file_of(wksq) == file_of(psq)) + if (forward_file_bb(WHITE, wksq) & psq) result = RookValueEg - distance(wksq, psq); // If the weaker side's king is too far from the pawn and the rook, @@ -248,7 +216,7 @@ Value Endgame::operator()(const Position& pos) const { } -/// KR vs KB. This is very simple, and always returns drawish scores. The +/// KR vs KB. This is very simple, and always returns drawish scores. The /// score is slightly bigger when the defending king is close to the edge. template<> Value Endgame::operator()(const Position& pos) const { @@ -532,7 +500,7 @@ ScaleFactor Endgame::operator()(const Position& pos) const { Square bsq = pos.square(weakSide); Square psq = pos.square(strongSide); Rank rk = relative_rank(strongSide, psq); - Square push = pawn_push(strongSide); + Direction push = pawn_push(strongSide); // If the pawn is on the 5th rank and the pawn (currently) is on // the same color square as the bishop then there is a chance of @@ -606,7 +574,7 @@ ScaleFactor Endgame::operator()(const Position& pos) const { // If all pawns are ahead of the king, on a single rook file and // the king is within one file of the pawns, it's a draw. - if ( !(pawns & ~in_front_bb(weakSide, rank_of(ksq))) + if ( !(pawns & ~forward_ranks_bb(weakSide, ksq)) && !((pawns & ~FileABB) && (pawns & ~FileHBB)) && distance(ksq, lsb(pawns)) <= 1) return SCALE_FACTOR_DRAW; @@ -639,29 +607,8 @@ ScaleFactor Endgame::operator()(const Position& pos) const { // Case 2: Opposite colored bishops if (opposite_colors(strongBishopSq, weakBishopSq)) - { - // We assume that the position is drawn in the following three situations: - // - // a. The pawn is on rank 5 or further back. - // b. The defending king is somewhere in the pawn's path. - // c. The defending bishop attacks some square along the pawn's path, - // and is at least three squares away from the pawn. - // - // These rules are probably not perfect, but in practice they work - // reasonably well. - - if (relative_rank(strongSide, pawnSq) <= RANK_5) - return SCALE_FACTOR_DRAW; - - Bitboard path = forward_bb(strongSide, pawnSq); - - if (path & pos.pieces(weakSide, KING)) - return SCALE_FACTOR_DRAW; + return SCALE_FACTOR_DRAW; - if ( (pos.attacks_from(weakBishopSq) & path) - && distance(weakBishopSq, pawnSq) >= 3) - return SCALE_FACTOR_DRAW; - } return SCALE_FACTOR_NONE; } @@ -788,7 +735,7 @@ ScaleFactor Endgame::operator()(const Position& pos) const { // King needs to get close to promoting pawn to prevent knight from blocking. // Rules for this are very tricky, so just approximate. - if (forward_bb(strongSide, pawnSq) & pos.attacks_from(bishopSq)) + if (forward_file_bb(strongSide, pawnSq) & pos.attacks_from(bishopSq)) return ScaleFactor(distance(weakKingSq, pawnSq)); return SCALE_FACTOR_NONE;