X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fpawns.cpp;h=cee744134f4f779031f73bd65aa20547367ce545;hp=6e564c9ddae2c6e6ea21829a085bfd6deab22c26;hb=14548312203bcd164f3bfb778c7e29abd89109dd;hpb=0d33466bcd84d9d58ea7049b224f375ba6a51221 diff --git a/src/pawns.cpp b/src/pawns.cpp index 6e564c9d..cee74413 100644 --- a/src/pawns.cpp +++ b/src/pawns.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) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + Copyright (C) 2015-2017 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 @@ -44,7 +44,7 @@ namespace { Score Connected[2][2][2][RANK_NB]; // Doubled pawn penalty - const Score Doubled = S(18,38); + const Score Doubled = S(18, 38); // Lever bonus by rank const Score Lever[RANK_NB] = { @@ -52,7 +52,8 @@ namespace { S(17, 16), S(33, 32), S(0, 0), S(0, 0) }; - // Weakness of our pawn shelter in front of the king by [distance from edge][rank] + // Weakness of our pawn shelter in front of the king by [distance from edge][rank]. + // RANK_1 = 0 is used for files where we have no pawns or our pawn is behind our king. const Value ShelterWeakness[][RANK_NB] = { { V(100), V(20), V(10), V(46), V(82), V( 86), V( 98) }, { V(116), V( 4), V(28), V(87), V(94), V(108), V(104) }, @@ -60,25 +61,26 @@ namespace { { V( 75), V(12), V(43), V(59), V(90), V( 84), V(112) } }; - // Danger of enemy pawns moving toward our king by [type][distance from edge][rank] + // Danger of enemy pawns moving toward our king by [type][distance from edge][rank]. + // For the unopposed and unblocked cases, RANK_1 = 0 is used when opponent has no pawn + // on the given file, or their pawn is behind our king. const Value StormDanger[][4][RANK_NB] = { - { { V( 4), V( 73), V( 132), V(46), V(31) }, + { { V( 0), V(-290), V(-274), V(57), V(41) }, //BlockedByKing + { V( 0), V( 60), V( 144), V(39), V(13) }, + { V( 0), V( 65), V( 141), V(41), V(34) }, + { V( 0), V( 53), V( 127), V(56), V(14) } }, + { { V( 4), V( 73), V( 132), V(46), V(31) }, //Unopposed { V( 1), V( 64), V( 143), V(26), V(13) }, { V( 1), V( 47), V( 110), V(44), V(24) }, { V( 0), V( 72), V( 127), V(50), V(31) } }, - { { V(22), V( 45), V( 104), V(62), V( 6) }, - { V(31), V( 30), V( 99), V(39), V(19) }, - { V(23), V( 29), V( 96), V(41), V(15) }, - { V(21), V( 23), V( 116), V(41), V(15) } }, - { { V( 0), V( 0), V( 79), V(23), V( 1) }, + { { V( 0), V( 0), V( 79), V(23), V( 1) }, //BlockedByPawn { V( 0), V( 0), V( 148), V(27), V( 2) }, { V( 0), V( 0), V( 161), V(16), V( 1) }, { V( 0), V( 0), V( 171), V(22), V(15) } }, - { { V( 0), V(-290), V(-274), V(57), V(41) }, - { V( 0), V( 60), V( 144), V(39), V(13) }, - { V( 0), V( 65), V( 141), V(41), V(34) }, - { V( 0), V( 53), V( 127), V(56), V(14) } } - + { { V(22), V( 45), V( 104), V(62), V( 6) }, //Unblocked + { V(31), V( 30), V( 99), V(39), V(19) }, + { V(23), V( 29), V( 96), V(41), V(15) }, + { V(21), V( 23), V( 116), V(41), V(15) } } }; // Max bonus for king safety. Corresponds to start position with all the pawns @@ -97,8 +99,9 @@ namespace { const Square Left = (Us == WHITE ? NORTH_WEST : SOUTH_EAST); Bitboard b, neighbours, stoppers, doubled, supported, phalanx; + Bitboard lever, leverPush, connected; Square s; - bool opposed, lever, connected, backward; + bool opposed, backward; Score score = SCORE_ZERO; const Square* pl = pos.squares(Us); const Bitboard* pawnAttacksBB = StepAttacksBB[make_piece(Us, PAWN)]; @@ -127,7 +130,8 @@ namespace { opposed = theirPawns & forward_bb(Us, s); stoppers = theirPawns & passed_pawn_mask(Us, s); lever = theirPawns & pawnAttacksBB[s]; - doubled = ourPawns & (s + Up); + leverPush = theirPawns & pawnAttacksBB[s + Up]; + doubled = ourPawns & (s - Up); neighbours = ourPawns & adjacent_files_bb(f); phalanx = neighbours & rank_bb(s); supported = neighbours & rank_bb(s - Up); @@ -151,8 +155,13 @@ namespace { } // Passed pawns will be properly scored in evaluation because we need - // full attack info to evaluate them. - if (!stoppers && !(ourPawns & forward_bb(Us, s))) + // full attack info to evaluate them. Include also not passed pawns + // which could become passed after one or two pawn pushes when are + // not attacked more times than defended. + if ( !(stoppers ^ lever ^ leverPush) + && !(ourPawns & forward_bb(Us, s)) + && popcount(supported) >= popcount(lever) + && popcount(phalanx) >= popcount(leverPush)) e->passedPawns[Us] |= s; // Score this pawn @@ -168,8 +177,8 @@ namespace { if (connected) score += Connected[opposed][!!phalanx][more_than_one(supported)][relative_rank(Us, s)]; - if (doubled) - score -= Doubled; + if (doubled && !supported) + score -= Doubled; if (lever) score += Lever[relative_rank(Us, s)]; @@ -224,14 +233,14 @@ Entry* probe(const Position& pos) { /// Entry::shelter_storm() calculates shelter and storm penalties for the file -/// the king is on, as well as the two adjacent files. +/// the king is on, as well as the two closest files. template Value Entry::shelter_storm(const Position& pos, Square ksq) { const Color Them = (Us == WHITE ? BLACK : WHITE); - enum { NoFriendlyPawn, Unblocked, BlockedByPawn, BlockedByKing }; + enum { BlockedByKing, Unopposed, BlockedByPawn, Unblocked }; Bitboard b = pos.pieces(PAWN) & (in_front_bb(Us, rank_of(ksq)) | rank_bb(ksq)); Bitboard ourPawns = b & pos.pieces(Us); @@ -247,12 +256,13 @@ Value Entry::shelter_storm(const Position& pos, Square ksq) { b = theirPawns & file_bb(f); Rank rkThem = b ? relative_rank(Us, frontmost_sq(Them, b)) : RANK_1; - safety -= ShelterWeakness[std::min(f, FILE_H - f)][rkUs] + int d = std::min(f, FILE_H - f); + safety -= ShelterWeakness[d][rkUs] + StormDanger [f == file_of(ksq) && rkThem == relative_rank(Us, ksq) + 1 ? BlockedByKing : - rkUs == RANK_1 ? NoFriendlyPawn : + rkUs == RANK_1 ? Unopposed : rkThem == rkUs + 1 ? BlockedByPawn : Unblocked] - [std::min(f, FILE_H - f)][rkThem]; + [d][rkThem]; } return safety;