X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Fpawns.cpp;h=b74f0659b24a371a92a6184ce5c73a50ea57ae7c;hb=f86d2aee29d9fd86a29e976698c76afc2a187903;hp=135633a3ab9f74d8f1e6654983df16d781a92365;hpb=404c4122ce8f5dd55593668fc87ae46236a71b92;p=stockfish diff --git a/src/pawns.cpp b/src/pawns.cpp index 135633a3..b74f0659 100644 --- a/src/pawns.cpp +++ b/src/pawns.cpp @@ -52,10 +52,16 @@ namespace { S(33, 31), S(33, 31), S(29, 31), S(20, 28) }}; // Pawn chain membership bonus by file - const Score ChainMember[FILE_NB] = { - S(11,-1), S(13,-1), S(13,-1), S(14,-1), - S(14,-1), S(13,-1), S(13,-1), S(11,-1) - }; + const Score ChainMember[FILE_NB][RANK_NB] = { + { S(0, 0), S(14, 0), S(16, 4), S(18, 9), S(56, 56), S(104, 208), S(236, 472) }, + { S(0, 0), S(16, 0), S(18, 5), S(20, 10), S(60, 60), S(108, 216), S(240, 480) }, + { S(0, 0), S(16, 0), S(18, 5), S(20, 10), S(60, 60), S(108, 216), S(240, 480) }, + { S(0, 0), S(17, 0), S(19, 6), S(22, 11), S(66, 66), S(118, 236), S(254, 508) }, + { S(0, 0), S(17, 0), S(19, 6), S(22, 11), S(66, 66), S(118, 236), S(254, 508) }, + { S(0, 0), S(16, 0), S(18, 5), S(20, 10), S(60, 60), S(108, 216), S(240, 480) }, + { S(0, 0), S(16, 0), S(18, 5), S(20, 10), S(60, 60), S(108, 216), S(240, 480) }, + { S(0, 0), S(14, 0), S(16, 4), S(18, 9), S(56, 56), S(104, 208), S(236, 472) } + }; // Candidate passed pawn bonus by rank const Score CandidatePassed[RANK_NB] = { @@ -63,15 +69,16 @@ namespace { S(34,68), S(83,166), S(0, 0), S( 0, 0) }; - // Weakness of our pawn shelter in front of the king indexed by [king pawn][rank] - const Value ShelterWeakness[2][RANK_NB] = - { { V(141), V(0), V(38), V(102), V(128), V(141), V(141) }, - { V( 61), V(0), V(16), V( 44), V( 56), V( 61), V( 61) } }; + // Weakness of our pawn shelter in front of the king indexed by [rank] + const Value ShelterWeakness[RANK_NB] = + { V(100), V(0), V(27), V(73), V(92), V(101), V(101) }; - // Danger of enemy pawns moving toward our king indexed by [pawn blocked][rank] - const Value StormDanger[2][RANK_NB] = - { { V(26), V(0), V(128), V(51), V(26) }, - { V(13), V(0), V( 64), V(25), V(13) } }; + // Danger of enemy pawns moving toward our king indexed by + // [no friendly pawn | pawn unblocked | pawn blocked][rank of enemy pawn] + const Value StormDanger[3][RANK_NB] = { + { V( 0), V(64), V(128), V(51), V(26) }, + { V(26), V(32), V( 96), V(38), V(20) }, + { V( 0), V( 0), V( 64), V(25), V(13) }}; // Max bonus for king safety. Corresponds to start position with all the pawns // in front of the king and no enemy pawn on the horizont. @@ -99,11 +106,11 @@ namespace { Bitboard ourPawns = pos.pieces(Us, PAWN); Bitboard theirPawns = pos.pieces(Them, PAWN); - e->passedPawns[Us] = 0; + e->passedPawns[Us] = e->candidatePawns[Us] = 0; e->kingSquares[Us] = SQ_NONE; e->semiopenFiles[Us] = 0xFF; e->pawnAttacks[Us] = shift_bb(ourPawns) | shift_bb(ourPawns); - e->pawnsOnSquares[Us][BLACK] = popcount(ourPawns & BlackSquares); + e->pawnsOnSquares[Us][BLACK] = popcount(ourPawns & DarkSquares); e->pawnsOnSquares[Us][WHITE] = pos.count(Us) - e->pawnsOnSquares[Us][BLACK]; // Loop through all pawns of the current color and score each pawn @@ -112,13 +119,13 @@ namespace { assert(pos.piece_on(s) == make_piece(Us, PAWN)); f = file_of(s); - r = rank_of(s); + r = relative_rank(Us, s); // This file cannot be semi-open e->semiopenFiles[Us] &= ~(1 << f); // Our rank plus previous one. Used for chain detection - b = rank_bb(r) | rank_bb(Us == WHITE ? r - Rank(1) : r + Rank(1)); + b = rank_bb(s) | rank_bb(s - pawn_push(Us)); // Flag the pawn as passed, isolated, doubled or member of a pawn // chain (but not the backward one). @@ -128,29 +135,25 @@ namespace { opposed = theirPawns & forward_bb(Us, s); passed = !(theirPawns & passed_pawn_mask(Us, s)); - // Test for backward pawn - backward = false; - + // Test for backward pawn. // If the pawn is passed, isolated, or member of a pawn chain it cannot // be backward. If there are friendly pawns behind on adjacent files // or if can capture an enemy pawn it cannot be backward either. - if ( !(passed | isolated | chain) - && !(ourPawns & pawn_attack_span(Them, s)) - && !(pos.attacks_from(s, Us) & theirPawns)) + if ( (passed | isolated | chain) + || (ourPawns & pawn_attack_span(Them, s)) + || (pos.attacks_from(s, Us) & theirPawns)) + backward = false; + else { // We now know that there are no friendly pawns beside or behind this // pawn on adjacent files. We now check whether the pawn is // backward by looking in the forward direction on the adjacent - // files, and seeing whether we meet a friendly or an enemy pawn first. - b = pos.attacks_from(s, Us); + // files, and picking the closest pawn there. + b = pawn_attack_span(Us, s) & (ourPawns | theirPawns); + b = pawn_attack_span(Us, s) & rank_bb(backmost_sq(Us, b)); - // Note that we are sure to find something because pawn is not passed - // nor isolated, so loop is potentially infinite, but it isn't. - while (!(b & (ourPawns | theirPawns))) - b = shift_bb(b); - - // The friendly pawn needs to be at least two ranks closer than the - // enemy pawn in order to help the potentially backward pawn advance. + // If we have an enemy pawn in the same or next rank, the pawn is + // backward because it cannot advance without being captured. backward = (b | shift_bb(b)) & theirPawns; } @@ -181,10 +184,15 @@ namespace { value -= Backward[opposed][f]; if (chain) - value += ChainMember[f]; + value += opposed ? ChainMember[f][r] / 2 : ChainMember[f][r]; if (candidate) - value += CandidatePassed[relative_rank(Us, s)]; + { + value += CandidatePassed[r]; + + if (!doubled) + e->candidatePawns[Us] |= s; + } } return value; @@ -222,24 +230,20 @@ Value Entry::shelter_storm(const Position& pos, Square ksq) { Value safety = MaxSafetyBonus; Bitboard b = pos.pieces(PAWN) & (in_front_bb(Us, rank_of(ksq)) | rank_bb(ksq)); - Bitboard ourPawns = b & pos.pieces(Us) & ~rank_bb(ksq); + Bitboard ourPawns = b & pos.pieces(Us); Bitboard theirPawns = b & pos.pieces(Them); Rank rkUs, rkThem; - File kf = file_of(ksq); - - kf = (kf == FILE_A) ? FILE_B : (kf == FILE_H) ? FILE_G : kf; + File kf = std::max(FILE_B, std::min(FILE_G, file_of(ksq))); - for (int f = kf - 1; f <= kf + 1; f++) + for (int f = kf - 1; f <= kf + 1; ++f) { - // Shelter penalty is higher for the pawn in front of the king b = ourPawns & FileBB[f]; - rkUs = b ? rank_of(Us == WHITE ? lsb(b) : ~msb(b)) : RANK_1; - safety -= ShelterWeakness[f != kf][rkUs]; + rkUs = b ? relative_rank(Us, backmost_sq(Us, b)) : RANK_1; + safety -= ShelterWeakness[rkUs]; - // Storm danger is smaller if enemy pawn is blocked b = theirPawns & FileBB[f]; - rkThem = b ? rank_of(Us == WHITE ? lsb(b) : ~msb(b)) : RANK_1; - safety -= StormDanger[rkThem == rkUs + 1][rkThem]; + rkThem = b ? relative_rank(Us, frontmost_sq(Them, b)) : RANK_1; + safety -= StormDanger[rkUs == RANK_1 ? 0 : rkThem == rkUs + 1 ? 2 : 1][rkThem]; } return safety;