X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;ds=sidebyside;f=src%2Fpawns.cpp;h=df8a68f961bf04d4c901621b3519db1568e726ed;hb=2c825294ecbc7c959af9bc05300efd137d9ec7c6;hp=74aa0e0dd95892df9b1cdd44e00dc0c9a6d02638;hpb=7487eb0dcae93731330f06c7d289ca156487a16f;p=stockfish diff --git a/src/pawns.cpp b/src/pawns.cpp index 74aa0e0d..df8a68f9 100644 --- a/src/pawns.cpp +++ b/src/pawns.cpp @@ -52,10 +52,15 @@ 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(28, 28), S(52, 104), S(118, 236) }, + { S(0, 0), S(16, 0), S(18, 5), S(20, 10), S(30, 30), S(54, 108), S(120, 240) }, + { S(0, 0), S(16, 0), S(18, 5), S(20, 10), S(30, 30), S(54, 108), S(120, 240) }, + { S(0, 0), S(17, 0), S(19, 6), S(22, 11), S(33, 33), S(59, 118), S(127, 254) }, + { S(0, 0), S(17, 0), S(19, 6), S(22, 11), S(33, 33), S(59, 118), S(127, 254) }, + { S(0, 0), S(16, 0), S(18, 5), S(20, 10), S(30, 30), S(54, 108), S(120, 240) }, + { S(0, 0), S(16, 0), S(18, 5), S(20, 10), S(30, 30), S(54, 108), S(120, 240) }, + { S(0, 0), S(14, 0), S(16, 4), S(18, 9), S(28, 28), S(52, 104), S(118, 236) }}; // Candidate passed pawn bonus by rank const Score CandidatePassed[RANK_NB] = { @@ -92,7 +97,6 @@ namespace { Bitboard b; Square s; File f; - Rank r; bool passed, isolated, doubled, opposed, chain, backward, candidate; Score value = SCORE_ZERO; const Square* pl = pos.list(Us); @@ -100,11 +104,11 @@ 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 @@ -113,13 +117,12 @@ namespace { assert(pos.piece_on(s) == make_piece(Us, PAWN)); f = file_of(s); - r = rank_of(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). @@ -129,29 +132,25 @@ 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; } @@ -182,10 +181,15 @@ namespace { value -= Backward[opposed][f]; if (chain) - value += ChainMember[f]; + value += ChainMember[f][relative_rank(Us, s)]; if (candidate) + { value += CandidatePassed[relative_rank(Us, s)]; + + if (!doubled) + e->candidatePawns[Us] |= s; + } } return value; @@ -226,18 +230,16 @@ Value Entry::shelter_storm(const Position& pos, Square 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) { b = ourPawns & FileBB[f]; - rkUs = b ? relative_rank(Us, Us == WHITE ? lsb(b) : msb(b)) : RANK_1; + rkUs = b ? relative_rank(Us, backmost_sq(Us, b)) : RANK_1; safety -= ShelterWeakness[rkUs]; b = theirPawns & FileBB[f]; - rkThem = b ? relative_rank(Us, Us == WHITE ? lsb(b) : msb(b)) : RANK_1; + rkThem = b ? relative_rank(Us, frontmost_sq(Them, b)) : RANK_1; safety -= StormDanger[rkUs == RANK_1 ? 0 : rkThem == rkUs + 1 ? 2 : 1][rkThem]; }