X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fendgame.cpp;h=56583c58890ffb6f7aac25979987719388407477;hp=55a4caba593a43c77bf3d3d2343f239f8b9a0301;hb=ddcbacd04d1c860e808202ce8c1206c8acdca627;hpb=cf5d683408a2ef8a1c80be9bf7d6790a38b16277 diff --git a/src/endgame.cpp b/src/endgame.cpp index 55a4caba..56583c58 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) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + Copyright (C) 2015-2020 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 @@ -18,49 +18,29 @@ along with this program. If not, see . */ -#include #include #include "bitboard.h" #include "endgame.h" #include "movegen.h" -using std::string; - namespace { - // Table used to drive the king towards the edge of the board + // Used to drive the king towards the edge of the board // in KX vs K and KQ vs KR endgames. - 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, - 70, 50, 30, 20, 20, 30, 50, 70, - 70, 50, 30, 20, 20, 30, 50, 70, - 80, 60, 40, 30, 30, 40, 60, 80, - 90, 70, 60, 50, 50, 60, 70, 90, - 100, 90, 80, 70, 70, 80, 90, 100 - }; - - // Table used to drive the king towards a corner square of the - // right color in KBN vs K endgames. - 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, - 170, 160, 140, 120, 110, 140, 150, 160, - 160, 150, 140, 110, 120, 140, 160, 170, - 150, 140, 125, 140, 140, 155, 170, 180, - 140, 130, 140, 150, 160, 170, 180, 190, - 130, 140, 150, 160, 170, 180, 190, 200 - }; - - // Tables used to drive a piece towards or away from another piece - 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 - constexpr int KRPPKRPScaleFactors[RANK_NB] = { 0, 9, 10, 14, 21, 44, 0, 0 }; + inline int push_to_edge(Square s) { + int rd = edge_distance(rank_of(s)), fd = edge_distance(file_of(s)); + return 90 - (7 * fd * fd / 2 + 7 * rd * rd / 2); + } + + // Used to drive the king towards A1H8 corners in KBN vs K endgames. + inline int push_to_corner(Square s) { + return abs(7 - rank_of(s) - file_of(s)); + } + + // Drive a piece close to or away from another piece + inline int push_close(Square s1, Square s2) { return 140 - 20 * distance(s1, s2); } + inline int push_away(Square s1, Square s2) { return 120 - push_close(s1, s2); } #ifndef NDEBUG bool verify_material(const Position& pos, Color c, Value npm, int pawnsCnt) { @@ -75,17 +55,42 @@ namespace { assert(pos.count(strongSide) == 1); if (file_of(pos.square(strongSide)) >= FILE_E) - sq = Square(sq ^ 7); // Mirror SQ_H1 -> SQ_A1 - - if (strongSide == BLACK) - sq = ~sq; + sq = flip_file(sq); - return sq; + return strongSide == WHITE ? sq : flip_rank(sq); } } // namespace +namespace Endgames { + + std::pair, Map> maps; + + void init() { + + add("KPK"); + add("KNNK"); + add("KBNK"); + add("KRKP"); + add("KRKB"); + add("KRKN"); + add("KQKP"); + add("KQKR"); + add("KNNKP"); + + add("KNPK"); + add("KNPKB"); + add("KRPKR"); + add("KRPKB"); + add("KBPKB"); + add("KBPKN"); + add("KBPPKB"); + add("KRPPKRP"); + } +} + + /// 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 @@ -105,22 +110,22 @@ Value Endgame::operator()(const Position& pos) const { Value result = pos.non_pawn_material(strongSide) + pos.count(strongSide) * PawnValueEg - + PushToEdges[loserKSq] - + PushClose[distance(winnerKSq, loserKSq)]; + + push_to_edge(loserKSq) + + push_close(winnerKSq, loserKSq); if ( pos.count(strongSide) || pos.count(strongSide) ||(pos.count(strongSide) && pos.count(strongSide)) || ( (pos.pieces(strongSide, BISHOP) & ~DarkSquares) && (pos.pieces(strongSide, BISHOP) & DarkSquares))) - result = std::min(result + VALUE_KNOWN_WIN, VALUE_MATE_IN_MAX_PLY - 1); + result = std::min(result + VALUE_KNOWN_WIN, VALUE_TB_WIN_IN_MAX_PLY - 1); return strongSide == pos.side_to_move() ? result : -result; } /// Mate with KBN vs K. This is similar to KX vs K, but we have to drive the -/// defending king towards a corner square of the right color. +/// defending king towards a corner square that our bishop attacks. template<> Value Endgame::operator()(const Position& pos) const { @@ -131,24 +136,19 @@ Value Endgame::operator()(const Position& pos) const { Square loserKSq = pos.square(weakSide); Square bishopSq = pos.square(strongSide); - // kbnk_mate_table() tries to drive toward corners A1 or H8. If we have a - // bishop that cannot reach the above squares, we flip the kings in order - // to drive the enemy toward corners A8 or H1. - if (opposite_colors(bishopSq, SQ_A1)) - { - winnerKSq = ~winnerKSq; - loserKSq = ~loserKSq; - } + // If our bishop does not attack A1/H8, we flip the enemy king square + // to drive to opposite corners (A8/H1). - Value result = VALUE_KNOWN_WIN - + PushClose[distance(winnerKSq, loserKSq)] - + PushToCorners[loserKSq]; + Value result = (VALUE_KNOWN_WIN + 3520) + + push_close(winnerKSq, loserKSq) + + 420 * push_to_corner(opposite_colors(bishopSq, SQ_A1) ? flip_file(loserKSq) : loserKSq); + assert(abs(result) < VALUE_TB_WIN_IN_MAX_PLY); return strongSide == pos.side_to_move() ? result : -result; } -/// KP vs K. This endgame is evaluated with the help of a bitbase. +/// KP vs K. This endgame is evaluated with the help of a bitbase template<> Value Endgame::operator()(const Position& pos) const { @@ -224,7 +224,7 @@ Value Endgame::operator()(const Position& pos) const { assert(verify_material(pos, strongSide, RookValueMg, 0)); assert(verify_material(pos, weakSide, BishopValueMg, 0)); - Value result = Value(PushToEdges[pos.square(weakSide)]); + Value result = Value(push_to_edge(pos.square(weakSide))); return strongSide == pos.side_to_move() ? result : -result; } @@ -239,7 +239,7 @@ Value Endgame::operator()(const Position& pos) const { Square bksq = pos.square(weakSide); Square bnsq = pos.square(weakSide); - Value result = Value(PushToEdges[bksq] + PushAway[distance(bksq, bnsq)]); + Value result = Value(push_to_edge(bksq) + push_away(bksq, bnsq)); return strongSide == pos.side_to_move() ? result : -result; } @@ -258,11 +258,11 @@ Value Endgame::operator()(const Position& pos) const { Square loserKSq = pos.square(weakSide); Square pawnSq = pos.square(weakSide); - Value result = Value(PushClose[distance(winnerKSq, loserKSq)]); + Value result = Value(push_close(winnerKSq, loserKSq)); if ( relative_rank(weakSide, pawnSq) != RANK_7 || distance(loserKSq, pawnSq) != 1 - || !((FileABB | FileCBB | FileFBB | FileHBB) & pawnSq)) + || ((FileBBB | FileDBB | FileEBB | FileGBB) & pawnSq)) result += QueenValueEg - PawnValueEg; return strongSide == pos.side_to_move() ? result : -result; @@ -284,8 +284,24 @@ Value Endgame::operator()(const Position& pos) const { Value result = QueenValueEg - RookValueEg - + PushToEdges[loserKSq] - + PushClose[distance(winnerKSq, loserKSq)]; + + push_to_edge(loserKSq) + + push_close(winnerKSq, loserKSq); + + return strongSide == pos.side_to_move() ? result : -result; +} + + +/// KNN vs KP. Very drawish, but there are some mate opportunities if we can +// press the weakSide King to a corner before the pawn advances too much. +template<> +Value Endgame::operator()(const Position& pos) const { + + assert(verify_material(pos, strongSide, 2 * KnightValueMg, 0)); + assert(verify_material(pos, weakSide, VALUE_ZERO, 1)); + + Value result = PawnValueEg + + 2 * push_to_edge(pos.square(weakSide)) + - 10 * relative_rank(weakSide, pos.square(weakSide)); return strongSide == pos.side_to_move() ? result : -result; } @@ -308,30 +324,28 @@ ScaleFactor Endgame::operator()(const Position& pos) const { // No assertions about the material of weakSide, because we want draws to // be detected even when the weaker side has some pawns. - Bitboard pawns = pos.pieces(strongSide, PAWN); - File pawnsFile = file_of(lsb(pawns)); + Bitboard strongPawns = pos.pieces(strongSide, PAWN); + Bitboard allPawns = pos.pieces(PAWN); - // All pawns are on a single rook file? - if ( (pawnsFile == FILE_A || pawnsFile == FILE_H) - && !(pawns & ~file_bb(pawnsFile))) + // All strongSide pawns are on a single rook file? + if (!(strongPawns & ~FileABB) || !(strongPawns & ~FileHBB)) { Square bishopSq = pos.square(strongSide); - Square queeningSq = relative_square(strongSide, make_square(pawnsFile, RANK_8)); - Square kingSq = pos.square(weakSide); + Square queeningSq = relative_square(strongSide, make_square(file_of(lsb(strongPawns)), RANK_8)); + Square weakKingSq = pos.square(weakSide); if ( opposite_colors(queeningSq, bishopSq) - && distance(queeningSq, kingSq) <= 1) + && distance(queeningSq, weakKingSq) <= 1) return SCALE_FACTOR_DRAW; } // If all the pawns are on the same B or G file, then it's potentially a draw - if ( (pawnsFile == FILE_B || pawnsFile == FILE_G) - && !(pos.pieces(PAWN) & ~file_bb(pawnsFile)) + if ((!(allPawns & ~FileBBB) || !(allPawns & ~FileGBB)) && pos.non_pawn_material(weakSide) == 0 && pos.count(weakSide) >= 1) { - // Get weakSide pawn that is closest to the home rank - Square weakPawnSq = backmost_sq(weakSide, pos.pieces(weakSide, PAWN)); + // Get the least advanced weakSide pawn + Square weakPawnSq = frontmost_sq(strongSide, pos.pieces(weakSide, PAWN)); Square strongKingSq = pos.square(strongSide); Square weakKingSq = pos.square(weakSide); @@ -340,8 +354,8 @@ ScaleFactor Endgame::operator()(const Position& pos) const { // There's potential for a draw if our pawn is blocked on the 7th rank, // the bishop cannot attack it or they only have one pawn left if ( relative_rank(strongSide, weakPawnSq) == RANK_7 - && (pos.pieces(strongSide, PAWN) & (weakPawnSq + pawn_push(weakSide))) - && (opposite_colors(bishopSq, weakPawnSq) || pos.count(strongSide) == 1)) + && (strongPawns & (weakPawnSq + pawn_push(weakSide))) + && (opposite_colors(bishopSq, weakPawnSq) || !more_than_one(strongPawns))) { int strongKingDist = distance(weakPawnSq, strongKingSq); int weakKingDist = distance(weakPawnSq, weakKingSq); @@ -554,7 +568,7 @@ ScaleFactor Endgame::operator()(const Position& pos) const { && relative_rank(strongSide, bksq) > r) { assert(r > RANK_1 && r < RANK_7); - return ScaleFactor(KRPPKRPScaleFactors[r]); + return ScaleFactor(7 * r); } return SCALE_FACTOR_NONE; } @@ -572,11 +586,9 @@ ScaleFactor Endgame::operator()(const Position& pos) const { Square ksq = pos.square(weakSide); Bitboard pawns = pos.pieces(strongSide, PAWN); - // 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 & ~forward_ranks_bb(weakSide, ksq)) - && !((pawns & ~FileABB) && (pawns & ~FileHBB)) - && distance(ksq, lsb(pawns)) <= 1) + // If all pawns are ahead of the king on a single rook file, it's a draw. + if (!((pawns & ~FileABB) || (pawns & ~FileHBB)) && + !(pawns & ~passed_pawn_span(weakSide, ksq))) return SCALE_FACTOR_DRAW; return SCALE_FACTOR_NONE; @@ -599,8 +611,7 @@ ScaleFactor Endgame::operator()(const Position& pos) const { Square weakKingSq = pos.square(weakSide); // Case 1: Defending king blocks the pawn, and cannot be driven away - if ( file_of(weakKingSq) == file_of(pawnSq) - && relative_rank(strongSide, pawnSq) < relative_rank(strongSide, weakKingSq) + if ( (forward_file_bb(strongSide, pawnSq) & weakKingSq) && ( opposite_colors(weakKingSq, strongBishopSq) || relative_rank(strongSide, weakKingSq) <= RANK_6)) return SCALE_FACTOR_DRAW; @@ -629,8 +640,6 @@ ScaleFactor Endgame::operator()(const Position& pos) const { Square ksq = pos.square(weakSide); Square psq1 = pos.squares(strongSide)[0]; Square psq2 = pos.squares(strongSide)[1]; - Rank r1 = rank_of(psq1); - Rank r2 = rank_of(psq2); Square blockSq1, blockSq2; if (relative_rank(strongSide, psq1) > relative_rank(strongSide, psq2)) @@ -664,7 +673,7 @@ ScaleFactor Endgame::operator()(const Position& pos) const { && opposite_colors(ksq, wbsq) && ( bbsq == blockSq2 || (pos.attacks_from(blockSq2) & pos.pieces(weakSide, BISHOP)) - || distance(r1, r2) >= 2)) + || distance(psq1, psq2) >= 2)) return SCALE_FACTOR_DRAW; else if ( ksq == blockSq2 @@ -729,6 +738,9 @@ ScaleFactor Endgame::operator()(const Position& pos) const { template<> ScaleFactor Endgame::operator()(const Position& pos) const { + assert(verify_material(pos, strongSide, KnightValueMg, 1)); + assert(verify_material(pos, weakSide, BishopValueMg, 0)); + Square pawnSq = pos.square(strongSide); Square bishopSq = pos.square(weakSide); Square weakKingSq = pos.square(weakSide);