// happen in Chess960 games.
const Score TrappedBishopA1H1Penalty = make_score(100, 100);
- // Penalty for a minor piece that is not defended by anything
- const Score UndefendedMinorPenalty = make_score(25, 10);
+ // Penalty for BNR that is not defended by anything
+ const Score UndefendedPiecePenalty = make_score(25, 10);
// The SpaceMask[Color] contains the area of the board which is considered
// by the space evaluation. In the middle game, each side is given a bonus
template<bool Trace>
Value do_evaluate(const Position& pos, Value& margin) {
+ assert(!pos.in_check());
+
EvalInfo ei;
Value margins[2];
Score score, mobilityWhite, mobilityBlack;
- assert(pos.thread() >= 0 && pos.thread() < MAX_THREADS);
- assert(!pos.in_check());
-
// Initialize score by reading the incrementally updated scores included
// in the position object (material + piece square tables).
score = pos.value();
const Color Them = (Us == WHITE ? BLACK : WHITE);
- Bitboard b;
+ Bitboard b, undefended, undefendedMinors, weakEnemies;
Score score = SCORE_ZERO;
- // Undefended minors get penalized even if not under attack
- const Bitboard undefended = pos.pieces(Them)
- & (pos.pieces(BISHOP) | pos.pieces(KNIGHT))
- & ~ei.attackedBy[Them][0];
- if (undefended) {
- score += UndefendedMinorPenalty;
- if (!single_bit(undefended))
- score += UndefendedMinorPenalty;
- }
+ // Undefended pieces get penalized even if not under attack
+ undefended = pos.pieces(Them) & ~ei.attackedBy[Them][0];
+ undefendedMinors = undefended & (pos.pieces(BISHOP) | pos.pieces(KNIGHT));
+
+ if (undefendedMinors)
+ score += single_bit(undefendedMinors) ? UndefendedPiecePenalty
+ : UndefendedPiecePenalty * 2;
+ if (undefended & pos.pieces(ROOK))
+ score += UndefendedPiecePenalty;
// Enemy pieces not defended by a pawn and under our attack
- const Bitboard weakEnemies = pos.pieces(Them)
- & ~ei.attackedBy[Them][PAWN]
- & ei.attackedBy[Us][0];
+ weakEnemies = pos.pieces(Them)
+ & ~ei.attackedBy[Them][PAWN]
+ & ei.attackedBy[Us][0];
+
if (!weakEnemies)
return score;