const Score Unstoppable = S( 0, 20);
const Score PawnlessFlank = S(20, 80);
const Score HinderPassedPawn = S( 7, 0);
+ const Score ThreatByRank = S(16, 3);
// Penalty for a bishop on a1/h1 (a8/h8 for black) which is trapped by
// a friendly pawn on b2/g2 (b7/g7 for black). This can obviously only
{
b = (defended | weak) & (ei.attackedBy[Us][KNIGHT] | ei.attackedBy[Us][BISHOP]);
while (b)
- score += Threat[Minor][type_of(pos.piece_on(pop_lsb(&b)))];
+ {
+ Square s = pop_lsb(&b);
+ score += Threat[Minor][type_of(pos.piece_on(s))];
+ if (type_of(pos.piece_on(s)) != PAWN)
+ score += ThreatByRank * (int)relative_rank(Them, s);
+ }
b = (pos.pieces(Them, QUEEN) | weak) & ei.attackedBy[Us][ROOK];
while (b)
- score += Threat[Rook ][type_of(pos.piece_on(pop_lsb(&b)))];
+ {
+ Square s = pop_lsb(&b);
+ score += Threat[Rook][type_of(pos.piece_on(s))];
+ if (type_of(pos.piece_on(s)) != PAWN)
+ score += ThreatByRank * (int)relative_rank(Them, s);
+ }
score += Hanging * popcount(weak & ~ei.attackedBy[Them][ALL_PIECES]);