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Move restricted squares to threats to recycle already calculated strong protection #413

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Merged
TheRealGioviok merged 1 commit into from
Jun 10, 2026
+4 −7
Merged

Move restricted squares to threats to recycle already calculated strong protection #413

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2 changes: 1 addition & 1 deletion src/eval_constants.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -18,7 +18,7 @@ inline const PParam BISHOP_PAIR_VAL = S(64, 230);
inline const PParam ROOK_OPEN_VAL = S(109, -2);
inline const PParam ROOK_SEMIOPEN_VAL = S(43, 13);
inline const PParam MINOR_BEHIND_PAWN = S(15, 39);
inline const PParam RESTRICTED_SQUARES = S(-20, -4);
inline const PParam RESTRICTED_SQUARES = S(20, 4);

inline const PParam DOUBLED_PAWN_VAL = S(-20, -82);
inline const PParam ISOLATED_PAWN_VAL = S(-14, -36);
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9 changes: 3 additions & 6 deletions src/evaluation.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -533,6 +533,9 @@ PScore evaluate_threats(const Position& pos, const EvalData& data) {
eval += HANGING_NON_PAWN * (b & opp_non_pawn).ipopcount();
}

eval += RESTRICTED_SQUARES
* (data.attacked_by(color) & ~strongly_protected & data.attacked_by(opp)).ipopcount();

Bitboard pawn_attacks = data.attacked_by(color, PieceType::Pawn);
eval +=
PAWN_THREAT_KNIGHT * (pos.bitboard_for(opp, PieceType::Knight) & pawn_attacks).ipopcount();
Expand Down Expand Up @@ -595,12 +598,6 @@ PScore evaluate_space(const Position& pos, const EvalData& data) {
& (pos.bitboard_for(them, PieceType::Pawn) | pos.bitboard_for(color, PieceType::Pawn)))
.ipopcount();

Bitboard strongly_defended = data.attacked_by(color, PieceType::Pawn)
| (data.attacked_by_2(color) & ~data.attacked_by_2(them));

eval += RESTRICTED_SQUARES
* (data.attacked_by(color) & ~strongly_defended & data.attacked_by(them)).ipopcount();

return eval;
}

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