X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fpawns.cpp;h=5d6770ed76eafb88bcd871a790f45c289a0b1e0a;hp=f18e03155042112dc71e89472b55120ad26c312b;hb=77eeea407c9d10cf6dbca6f4e07efbbe836c4fb0;hpb=7225d254f90c7b9d64d4adf85ec2d319c6cf75a0 diff --git a/src/pawns.cpp b/src/pawns.cpp index f18e0315..5d6770ed 100644 --- a/src/pawns.cpp +++ b/src/pawns.cpp @@ -1,8 +1,6 @@ /* 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) 2015-2020 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + Copyright (C) 2004-2021 The Stockfish developers (see AUTHORS file) Stockfish is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -32,29 +30,30 @@ namespace { #define S(mg, eg) make_score(mg, eg) // Pawn penalties - constexpr Score Backward = S( 9, 24); - constexpr Score Doubled = S(11, 56); - constexpr Score Isolated = S( 5, 15); - constexpr Score WeakLever = S( 0, 56); - constexpr Score WeakUnopposed = S(13, 27); + constexpr Score Backward = S( 6, 23); + constexpr Score Doubled = S(13, 53); + constexpr Score DoubledEarly = S(20, 10); + constexpr Score Isolated = S( 2, 15); + constexpr Score WeakLever = S( 5, 57); + constexpr Score WeakUnopposed = S(16, 22); // Bonus for blocked pawns at 5th or 6th rank - constexpr Score BlockedPawn[2] = { S(-10, -3), S(-3, 3) }; + constexpr Score BlockedPawn[2] = { S(-15, -3), S(-6, 3) }; constexpr Score BlockedStorm[RANK_NB] = { - S(0, 0), S(0, 0), S(76, 78), S(-10, 15), S(-7, 10), S(-4, 6), S(-1, 2) + S(0, 0), S(0, 0), S(75, 78), S(-8, 16), S(-6, 10), S(-6, 6), S(0, 2) }; // Connected pawn bonus - constexpr int Connected[RANK_NB] = { 0, 7, 8, 12, 29, 48, 86 }; + constexpr int Connected[RANK_NB] = { 0, 5, 7, 11, 24, 48, 86 }; // Strength of pawn shelter for our king by [distance from edge][rank]. // RANK_1 = 0 is used for files where we have no pawn, or pawn is behind our king. constexpr Value ShelterStrength[int(FILE_NB) / 2][RANK_NB] = { - { V( -6), V( 81), V( 93), V( 58), V( 39), V( 18), V( 25) }, - { V(-43), V( 61), V( 35), V(-49), V(-29), V(-11), V( -63) }, - { V(-10), V( 75), V( 23), V( -2), V( 32), V( 3), V( -45) }, - { V(-39), V(-13), V(-29), V(-52), V(-48), V(-67), V(-166) } + { V( -5), V( 82), V( 92), V( 54), V( 36), V( 22), V( 28) }, + { V(-44), V( 63), V( 33), V(-50), V(-30), V(-12), V( -62) }, + { V(-11), V( 77), V( 22), V( -6), V( 31), V( 8), V( -45) }, + { V(-39), V(-12), V(-29), V(-50), V(-43), V(-68), V(-164) } }; // Danger of enemy pawns moving toward our king by [distance from edge][rank]. @@ -62,12 +61,18 @@ namespace { // is behind our king. Note that UnblockedStorm[0][1-2] accommodate opponent pawn // on edge, likely blocked by our king. constexpr Value UnblockedStorm[int(FILE_NB) / 2][RANK_NB] = { - { V( 85), V(-289), V(-166), V(97), V(50), V( 45), V( 50) }, - { V( 46), V( -25), V( 122), V(45), V(37), V(-10), V( 20) }, - { V( -6), V( 51), V( 168), V(34), V(-2), V(-22), V(-14) }, - { V(-15), V( -11), V( 101), V( 4), V(11), V(-15), V(-29) } + { V( 87), V(-288), V(-168), V( 96), V( 47), V( 44), V( 46) }, + { V( 42), V( -25), V( 120), V( 45), V( 34), V( -9), V( 24) }, + { V( -8), V( 51), V( 167), V( 35), V( -4), V(-16), V(-12) }, + { V(-17), V( -13), V( 100), V( 4), V( 9), V(-16), V(-31) } }; + + // KingOnFile[semi-open Us][semi-open Them] contains bonuses/penalties + // for king when the king is on a semi-open or open file. + constexpr Score KingOnFile[2][2] = {{ S(-21,10), S(-7, 1) }, + { S( 0,-3), S( 9,-4) }}; + #undef S #undef V @@ -82,13 +87,14 @@ namespace { constexpr Color Them = ~Us; constexpr Direction Up = pawn_push(Us); + constexpr Direction Down = -Up; Bitboard neighbours, stoppers, support, phalanx, opposed; Bitboard lever, leverPush, blocked; Square s; bool backward, passed, doubled; Score score = SCORE_ZERO; - const Square* pl = pos.squares(Us); + Bitboard b = pos.pieces(Us, PAWN); Bitboard ourPawns = pos.pieces( Us, PAWN); Bitboard theirPawns = pos.pieces(Them, PAWN); @@ -101,8 +107,9 @@ namespace { e->blockedCount += popcount(shift(ourPawns) & (theirPawns | doubleAttackThem)); // Loop through all pawns of the current color and score each pawn - while ((s = *pl++) != SQ_NONE) - { + while (b) { + s = pop_lsb(&b); + assert(pos.piece_on(s) == make_piece(Us, PAWN)); Rank r = relative_rank(Us, s); @@ -118,6 +125,13 @@ namespace { phalanx = neighbours & rank_bb(s); support = neighbours & rank_bb(s - Up); + if (doubled) + { + // Additional doubled penalty if none of their pawns is fixed + if (!(ourPawns & shift(theirPawns | pawn_attacks_bb(theirPawns)))) + score -= DoubledEarly; + } + // A pawn is backward when it is behind all pawns of the same color on // the adjacent files and cannot safely advance. backward = !(neighbours & forward_ranks_bb(Them, s + Up)) @@ -148,8 +162,8 @@ namespace { // Score this pawn if (support | phalanx) { - int v = Connected[r] * (4 + 2 * bool(phalanx) - 2 * bool(opposed) - bool(blocked)) / 2 - + 21 * popcount(support); + int v = Connected[r] * (2 + bool(phalanx) - bool(opposed)) + + 22 * popcount(support); score += make_score(v, v * (r - 2) / 4); } @@ -167,14 +181,14 @@ namespace { else if (backward) score -= Backward - + WeakUnopposed * !opposed; + + WeakUnopposed * !opposed * bool(~(FileABB | FileHBB) & s); if (!support) score -= Doubled * doubled + WeakLever * more_than_one(lever); - if (blocked && r > RANK_4) - score += BlockedPawn[r-4]; + if (blocked && r >= RANK_5) + score += BlockedPawn[r - RANK_5]; } return score; @@ -221,7 +235,7 @@ Score Entry::evaluate_shelter(const Position& pos, Square ksq) const { Score bonus = make_score(5, 5); - File center = Utility::clamp(file_of(ksq), FILE_B, FILE_G); + File center = std::clamp(file_of(ksq), FILE_B, FILE_G); for (File f = File(center - 1); f <= File(center + 1); ++f) { b = ourPawns & file_bb(f); @@ -239,6 +253,9 @@ Score Entry::evaluate_shelter(const Position& pos, Square ksq) const { bonus -= make_score(UnblockedStorm[d][theirRank], 0); } + // King On File + bonus -= KingOnFile[pos.is_on_semiopen_file(Us, ksq)][pos.is_on_semiopen_file(Them, ksq)]; + return bonus; }