namespace {
+ #define V Value
#define S(mg, eg) make_score(mg, eg)
// Doubled pawn penalty by opposed flag and file
const Score PawnStructureWeight = S(233, 201);
- #undef S
-
- typedef Value V;
-
// Weakness of our pawn shelter in front of the king indexed by [king pawn][rank]
const Value ShelterWeakness[2][8] =
- { { V(141), V(0), V(38), V(102), V(128), V(141), V(141), V(141) },
- { V( 61), V(0), V(16), V( 44), V( 56), V( 61), V( 61), V( 61) } };
+ { { V(141), V(0), V(38), V(102), V(128), V(141), V(141) },
+ { V( 61), V(0), V(16), V( 44), V( 56), V( 61), V( 61) } };
// Danger of enemy pawns moving toward our king indexed by [pawn blocked][rank]
const Value StormDanger[2][8] =
- { { V(26), V(0), V(128), V(51), V(26), V(0), V(0), V(0) },
- { V(13), V(0), V( 64), V(25), V(13), V(0), V(0), V(0) } };
+ { { V(26), V(0), V(128), V(51), V(26) },
+ { V(13), V(0), V( 64), V(25), V(13) } };
// Max bonus for king safety. Corresponds to start position with all the pawns
- // in front of the king and no enemy pawns on the horizont.
+ // in front of the king and no enemy pawn on the horizont.
const Value MaxSafetyBonus = V(263);
+ #undef S
+ #undef V
+
inline Score apply_weight(Score v, Score w) {
return make_score((int(mg_value(v)) * mg_value(w)) / 0x100,
(int(eg_value(v)) * eg_value(w)) / 0x100);
}
+/// PawnInfo::shelter_storm() calculates shelter and storm penalties for the file
+/// the king is on, as well as the two adjacent files.
+
template<Color Us>
-int PawnInfo::shelter_storm(const Position& pos, Square ksq) {
+Value PawnInfo::shelter_storm(const Position& pos, Square ksq) {
const Color Them = (Us == WHITE ? BLACK : WHITE);
- int safety = 0;
- Bitboard b = pos.pieces(PAWN) & (in_front_bb(Us, ksq) | RankBB[rank_of(ksq)]);
- Bitboard ourPawns = b & pos.pieces(Us) & ~RankBB[rank_of(ksq)];
+ Value safety = MaxSafetyBonus;
+ Bitboard b = pos.pieces(PAWN) & (in_front_bb(Us, ksq) | rank_bb(ksq));
+ Bitboard ourPawns = b & pos.pieces(Us) & ~rank_bb(ksq);
Bitboard theirPawns = b & pos.pieces(Them);
Rank rkUs, rkThem;
File kf = file_of(ksq);
- // Compute shelter and storm values for the file the king is on, as well as
- // the two adjacent files. Computation is done from the white point of view.
kf = (kf == FILE_A) ? kf++ : (kf == FILE_H) ? kf-- : kf;
for (int f = kf - 1; f <= kf + 1; f++)
template<Color Us>
Score PawnInfo::update_safety(const Position& pos, Square ksq) {
- int bonus = 0;
+ kingSquares[Us] = ksq;
- if (relative_rank(Us, ksq) <= RANK_4)
- {
- bonus = shelter_storm<Us>(pos, ksq);
+ if (relative_rank(Us, ksq) > RANK_4)
+ return kingShelters[Us] = SCORE_ZERO;
- // If we can castle use the bonus after the castle if is bigger
- if (pos.can_castle(Us == WHITE ? WHITE_OO : BLACK_OO))
- bonus = std::max(bonus, shelter_storm<Us>(pos, relative_square(Us, SQ_G1)));
+ Value bonus = shelter_storm<Us>(pos, ksq);
- if (pos.can_castle(Us == WHITE ? WHITE_OOO : BLACK_OOO))
- bonus = std::max(bonus, shelter_storm<Us>(pos, relative_square(Us, SQ_C1)));
+ // If we can castle use the bonus after the castle if is bigger
+ if (pos.can_castle(Us == WHITE ? WHITE_OO : BLACK_OO))
+ bonus = std::max(bonus, shelter_storm<Us>(pos, relative_square(Us, SQ_G1)));
- bonus += MaxSafetyBonus; // Offset to be sure bonus is always positive
- }
+ if (pos.can_castle(Us == WHITE ? WHITE_OOO : BLACK_OOO))
+ bonus = std::max(bonus, shelter_storm<Us>(pos, relative_square(Us, SQ_C1)));
- kingSquares[Us] = ksq;
- kingShelters[Us] = make_score(bonus, 0);
- return kingShelters[Us];
+ return kingShelters[Us] = make_score(bonus, 0);
}
// Explicit template instantiation