- // evaluate_threats<>() assigns bonuses according to the type of attacking piece
- // and the type of attacked one.
-
- template<Color Us, bool Trace>
- Score evaluate_threats(const Position& pos, const EvalInfo& ei) {
-
- const Color Them = (Us == WHITE ? BLACK : WHITE);
-
- Bitboard b, undefendedMinors, weakEnemies;
- Score score = SCORE_ZERO;
-
- // Undefended minors get penalized even if not under attack
- undefendedMinors = pos.pieces(Them, BISHOP, KNIGHT)
- & ~ei.attackedBy[Them][ALL_PIECES];
-
- if (undefendedMinors)
- score += UndefendedMinor;
-
- // Enemy pieces not defended by a pawn and under our attack
- weakEnemies = pos.pieces(Them)
- & ~ei.attackedBy[Them][PAWN]
- & ei.attackedBy[Us][ALL_PIECES];
-
- // Add bonus according to type of attacked enemy piece and to the
- // type of attacking piece, from knights to queens. Kings are not
- // considered because are already handled in king evaluation.
- if (weakEnemies)
- for (PieceType pt1 = KNIGHT; pt1 < KING; ++pt1)
- {
- b = ei.attackedBy[Us][pt1] & weakEnemies;
- if (b)
- for (PieceType pt2 = PAWN; pt2 < KING; ++pt2)
- if (b & pos.pieces(pt2))
- score += Threat[pt1][pt2];
- }
-
- if (Trace)
- Tracing::scores[Us][THREAT] = score;
-
- return score;
- }
-
-
- // evaluate_pieces_of_color<>() assigns bonuses and penalties to all the