};
// Danger of enemy pawns moving toward our king by [type][distance from edge][rank].
- // For the unopposed and unblocked cases, RANK_1 = 0 is used when opponent has
- // no pawn on the given file, or their pawn is behind our king.
+ // For the unblocked case, RANK_1 = 0 is used when opponent has no pawn on the
+ // given file, or their pawn is behind our king.
constexpr Value StormDanger[][4][RANK_NB] = {
- { { V(11), V( 79), V(132), V( 68), V( 33) }, // Unopposed
- { V( 4), V(104), V(155), V( 4), V( 21) },
- { V(-7), V( 59), V(142), V( 45), V( 30) },
- { V( 0), V( 62), V(113), V( 43), V( 13) } },
+ { { V(25), V( 79), V(107), V( 51), V( 27) }, // UnBlocked
+ { V(15), V( 45), V(131), V( 8), V( 25) },
+ { V( 0), V( 42), V(118), V( 56), V( 27) },
+ { V( 3), V( 54), V(110), V( 55), V( 26) } },
{ { V( 0), V( 0), V( 37), V( 5), V(-48) }, // BlockedByPawn
{ V( 0), V( 0), V( 68), V(-12), V( 13) },
{ V( 0), V( 0), V(111), V(-25), V( -3) },
- { V( 0), V( 0), V(108), V( 14), V( 21) } },
- { { V(38), V( 78), V( 83), V( 35), V( 22) }, // Unblocked
- { V(33), V(-15), V(108), V( 12), V( 28) },
- { V( 8), V( 25), V( 94), V( 68), V( 25) },
- { V( 6), V( 48), V(120), V( 68), V( 40) } }
+ { V( 0), V( 0), V(108), V( 14), V( 21) } }
};
#undef S
template<Color Us>
Value Entry::evaluate_shelter(const Position& pos, Square ksq) {
- enum { Unopposed, BlockedByPawn, Unblocked };
+ enum { UnBlocked, BlockedByPawn };
constexpr Color Them = (Us == WHITE ? BLACK : WHITE);
constexpr Direction Down = (Us == WHITE ? SOUTH : NORTH);
constexpr Bitboard BlockRanks = (Us == WHITE ? Rank1BB | Rank2BB : Rank8BB | Rank7BB);
Value safety = (ourPawns & file_bb(ksq)) ? Value(5) : Value(-5);
if (shift<Down>(theirPawns) & (FileABB | FileHBB) & BlockRanks & ksq)
- safety += 374;
+ safety += Value(374);
File center = std::max(FILE_B, std::min(FILE_G, file_of(ksq)));
for (File f = File(center - 1); f <= File(center + 1); ++f)
{
b = ourPawns & file_bb(f);
- Rank rkUs = b ? relative_rank(Us, backmost_sq(Us, b)) : RANK_1;
+ int ourRank = b ? relative_rank(Us, backmost_sq(Us, b)) : 0;
b = theirPawns & file_bb(f);
- Rank rkThem = b ? relative_rank(Us, frontmost_sq(Them, b)) : RANK_1;
+ int theirRank = b ? relative_rank(Us, frontmost_sq(Them, b)) : 0;
int d = std::min(f, ~f);
- safety += ShelterStrength[d][rkUs]
- - StormDanger[rkUs == RANK_1 ? Unopposed :
- rkUs == rkThem - 1 ? BlockedByPawn : Unblocked]
- [d][rkThem];
+
+ safety += ShelterStrength[d][ourRank];
+ if (ourRank || theirRank)
+ safety -= StormDanger[ourRank && (ourRank == theirRank - 1) ? BlockedByPawn : UnBlocked][d][theirRank];
}
return safety;