kate/BadFish
1
0
Fork 0
mirror of https://github.com/sockspls/badfish synced 2025-04-30 00:33:09 +00:00
Code Issues Releases Wiki Activity

Improve signature of evaluate_shelter()

Browse source 
Remove one parameter in function evaluate_shelter(), making all
comparisons for castled/uncastled shelter locally in do_king_safety().
Also introduce BlockedStorm penalty.

Passed non-regression test at STC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 65864 W: 14630 L: 14596 D: 36638
http://tests.stockfishchess.org/tests/view/5d5fc80c0ebc5939d09f0acc

No functional change
This commit is contained in:
protonspring 2019-08-24 08:16:20 +02:00 • committed by Stéphane Nicolet
parent 3984b8f8f0
commit d799529b48
2 changed files with 22 additions and 17 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

37
src/pawns.cpp
View file

@ -33,6 +33,7 @@ namespace {
// Pawn penalties // Pawn penalties
constexpr Score Backward = S( 9, 24); constexpr Score Backward = S( 9, 24);
constexpr Score BlockedStorm = S(82, 82);
constexpr Score Doubled = S(11, 56); constexpr Score Doubled = S(11, 56);
constexpr Score Isolated = S( 5, 15); constexpr Score Isolated = S( 5, 15);
constexpr Score WeakLever = S( 0, 56); constexpr Score WeakLever = S( 0, 56);
@ -182,7 +183,7 @@ Entry* probe(const Position& pos) {
/// penalty for a king, looking at the king file and the two closest files. /// penalty for a king, looking at the king file and the two closest files.
template<Color Us> template<Color Us>
void Entry::evaluate_shelter(const Position& pos, Square ksq, Score& shelter) { Score Entry::evaluate_shelter(const Position& pos, Square ksq) {
constexpr Color Them = (Us == WHITE ? BLACK : WHITE); constexpr Color Them = (Us == WHITE ? BLACK : WHITE);
@ -205,13 +206,12 @@ void Entry::evaluate_shelter(const Position& pos, Square ksq, Score& shelter) {
bonus += make_score(ShelterStrength[d][ourRank], 0); bonus += make_score(ShelterStrength[d][ourRank], 0);
if (ourRank && (ourRank == theirRank - 1)) if (ourRank && (ourRank == theirRank - 1))
bonus -= make_score(82 * (theirRank == RANK_3), 82 * (theirRank == RANK_3)); bonus -= BlockedStorm * int(theirRank == RANK_3);
else else
bonus -= make_score(UnblockedStorm[d][theirRank], 0); bonus -= make_score(UnblockedStorm[d][theirRank], 0);
} }
if (mg_value(bonus) > mg_value(shelter)) return bonus;
shelter = bonus;
} }
@ -225,26 +225,31 @@ Score Entry::do_king_safety(const Position& pos) {
kingSquares[Us] = ksq; kingSquares[Us] = ksq;
castlingRights[Us] = pos.castling_rights(Us); castlingRights[Us] = pos.castling_rights(Us);
Score shelters[3] = { evaluate_shelter<Us>(pos, ksq),
make_score(-VALUE_INFINITE, 0),
make_score(-VALUE_INFINITE, 0) };
// If we can castle use the bonus after castling if it is bigger
if (pos.can_castle(Us & KING_SIDE))
shelters[1] = evaluate_shelter<Us>(pos, relative_square(Us, SQ_G1));
if (pos.can_castle(Us & QUEEN_SIDE))
shelters[2] = evaluate_shelter<Us>(pos, relative_square(Us, SQ_C1));
for (int i : {1, 2})
if (mg_value(shelters[i]) > mg_value(shelters[0]))
shelters[0] = shelters[i];
// In endgame we like to bring our king near our closest pawn
Bitboard pawns = pos.pieces(Us, PAWN); Bitboard pawns = pos.pieces(Us, PAWN);
int minPawnDist = pawns ? 8 : 0; int minPawnDist = pawns ? 8 : 0;
if (pawns & PseudoAttacks[KING][ksq]) if (pawns & PseudoAttacks[KING][ksq])
minPawnDist = 1; minPawnDist = 1;
else while (pawns) else while (pawns)
minPawnDist = std::min(minPawnDist, distance(ksq, pop_lsb(&pawns))); minPawnDist = std::min(minPawnDist, distance(ksq, pop_lsb(&pawns)));
Score shelter = make_score(-VALUE_INFINITE, 0); return shelters[0] - make_score(0, 16 * minPawnDist);
evaluate_shelter<Us>(pos, ksq, shelter);
// If we can castle use the bonus after the castling if it is bigger
if (pos.can_castle(Us & KING_SIDE))
evaluate_shelter<Us>(pos, relative_square(Us, SQ_G1), shelter);
if (pos.can_castle(Us & QUEEN_SIDE))
evaluate_shelter<Us>(pos, relative_square(Us, SQ_C1), shelter);
return shelter - make_score(0, 16 * minPawnDist);
} }
// Explicit template instantiation // Explicit template instantiation

2
src/pawns.h
View file

@ -49,7 +49,7 @@ struct Entry {
Score do_king_safety(const Position& pos); Score do_king_safety(const Position& pos);
template<Color Us> template<Color Us>
void evaluate_shelter(const Position& pos, Square ksq, Score& shelter); Score evaluate_shelter(const Position& pos, Square ksq);
Key key; Key key;
Score scores[COLOR_NB]; Score scores[COLOR_NB];