constexpr Value SpaceThreshold = Value(12222);
// KingAttackWeights[PieceType] contains king attack weights by piece type
- constexpr int KingAttackWeights[PIECE_TYPE_NB] = { 0, 0, 78, 56, 45, 11 };
+ constexpr int KingAttackWeights[PIECE_TYPE_NB] = { 0, 0, 77, 55, 44, 10 };
// Penalties for enemy's safe checks
constexpr int QueenSafeCheck = 780;
else if (file_of(pos.square<KING>(Us)) == FILE_A)
kingRing[Us] |= shift<EAST>(kingRing[Us]);
- kingAttackersCount[Them] = popcount(attackedBy[Us][KING] & pe->pawn_attacks(Them));
+ kingAttackersCount[Them] = popcount(kingRing[Us] & pe->pawn_attacks(Them));
kingAttacksCount[Them] = kingAttackersWeight[Them] = 0;
}
else
: AllSquares ^ Rank1BB ^ Rank2BB ^ Rank3BB);
const Square ksq = pos.square<KING>(Us);
- Bitboard weak, b, b1, b2, safe, unsafeChecks, pinned;
+ Bitboard weak, b, b1, b2, safe, unsafeChecks;
// King shelter and enemy pawns storm
Score score = pe->king_safety<Us>(pos, ksq);
// Unsafe or occupied checking squares will also be considered, as long as
// the square is in the attacker's mobility area.
unsafeChecks &= mobilityArea[Them];
- pinned = pos.blockers_for_king(Us) & pos.pieces(Us);
kingDanger += kingAttackersCount[Them] * kingAttackersWeight[Them]
+ 102 * kingAttacksCount[Them]
+ 191 * popcount(kingRing[Us] & weak)
- + 143 * popcount(pinned | unsafeChecks)
+ + 143 * popcount(pos.blockers_for_king(Us) | unsafeChecks)
- 848 * !pos.count<QUEEN>(Them)
- 9 * mg_value(score) / 8
+ 40;
// If scale is not already specific, scale down the endgame via general heuristics
if (sf == SCALE_FACTOR_NORMAL)
{
- if (pos.opposite_bishops())
- {
+ if ( pos.opposite_bishops()
+ && pos.non_pawn_material(WHITE) == BishopValueMg
+ && pos.non_pawn_material(BLACK) == BishopValueMg)
// Endgame with opposite-colored bishops and no other pieces is almost a draw
- if ( pos.non_pawn_material(WHITE) == BishopValueMg
- && pos.non_pawn_material(BLACK) == BishopValueMg)
- sf = 31;
-
- // Endgame with opposite-colored bishops, but also other pieces. Still
- // a bit drawish, but not as drawish as with only the two bishops.
- else
- sf = 46;
- }
+ sf = 31;
else
- sf = std::min(40 + 7 * pos.count<PAWN>(strongSide), sf);
+ sf = std::min(40 + (pos.opposite_bishops()? 2 : 7) * pos.count<PAWN>(strongSide), sf);
}
return ScaleFactor(sf);