kate/BadFish
1
0
Fork 0
mirror of https://github.com/sockspls/badfish synced 2025-07-11 19:49:14 +00:00
Code Issues Releases Wiki Activity

Last touches to pawns shelter code

Browse source 
No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Marco Costalba 2012-03-29 06:04:44 +01:00
parent 5e18b81e87
commit b0b9bb3462
2 changed files with 31 additions and 34 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

63
src/pawns.cpp
View file

@ -26,6 +26,7 @@
namespace {
#define V Value
#define S(mg, eg) make_score(mg, eg)
// Doubled pawn penalty by opposed flag and file
@ -63,24 +64,23 @@ namespace {
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);
@ -226,20 +226,21 @@ Score PawnInfoTable::evaluate_pawns(const Position& pos, Bitboard ourPawns,
}
/// 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++)
@ -265,25 +266,21 @@ int PawnInfo::shelter_storm(const Position& pos, Square ksq) {
template<Color Us>
Score PawnInfo::update_safety(const Position& pos, Square ksq) {
int bonus = 0;
if (relative_rank(Us, ksq) <= RANK_4)
{
bonus = shelter_storm<Us>(pos, ksq);
// 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)));
if (pos.can_castle(Us == WHITE ? WHITE_OOO : BLACK_OOO))
bonus = std::max(bonus, shelter_storm<Us>(pos, relative_square(Us, SQ_C1)));
bonus += MaxSafetyBonus; // Offset to be sure bonus is always positive
}
kingSquares[Us] = ksq;
kingShelters[Us] = make_score(bonus, 0);
return kingShelters[Us];
if (relative_rank(Us, ksq) > RANK_4)
return kingShelters[Us] = SCORE_ZERO;
Value bonus = shelter_storm<Us>(pos, ksq);
// 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)));
if (pos.can_castle(Us == WHITE ? WHITE_OOO : BLACK_OOO))
bonus = std::max(bonus, shelter_storm<Us>(pos, relative_square(Us, SQ_C1)));
return kingShelters[Us] = make_score(bonus, 0);
}
// Explicit template instantiation

2
src/pawns.h
View file

@ -53,7 +53,7 @@ private:
Score update_safety(const Position& pos, Square ksq);
template<Color Us>
int shelter_storm(const Position& pos, Square ksq);
Value shelter_storm(const Position& pos, Square ksq);
Key key;
Bitboard passedPawns[2];