We double the bonus for potential threats by minors and rooks against
our queen, in case of "queen vs pieces imbalance". Hopefully this will
improve a little bit the evaluation for this well-known Stockfish weakness.
passed STC:
LLR: 2.93 (-2.94,2.94) {-0.50,1.50}
Total: 72976 W: 14003 L: 13710 D: 45263
Ptnml(0-2): 1218, 8370, 17094, 8513, 1293
https://tests.stockfishchess.org/tests/view/
5efa50eb020eec13834a977d
passed LTC:
LLR: 2.93 (-2.94,2.94) {0.25,1.75}
Total: 22232 W: 2779 L: 2560 D: 16893
Ptnml(0-2): 129, 1885, 6896, 2050, 156
https://tests.stockfishchess.org/tests/view/
5f1fdd2dc09435d870cb9f13
closes https://github.com/official-stockfish/Stockfish/pull/2864
Bench:
4367349
// Bonus for threats on the next moves against enemy queen
if (pos.count<QUEEN>(Them) == 1)
{
+ bool queenImbalance = pos.count<QUEEN>() == 1;
+
Square s = pos.square<QUEEN>(Them);
- safe = mobilityArea[Us] & ~stronglyProtected;
+ safe = mobilityArea[Us]
+ & ~pos.pieces(Us, PAWN)
+ & ~stronglyProtected;
b = attackedBy[Us][KNIGHT] & attacks_bb<KNIGHT>(s);
- score += KnightOnQueen * popcount(b & safe);
+ score += KnightOnQueen * popcount(b & safe) * (1 + queenImbalance);
b = (attackedBy[Us][BISHOP] & attacks_bb<BISHOP>(s, pos.pieces()))
| (attackedBy[Us][ROOK ] & attacks_bb<ROOK >(s, pos.pieces()));
- score += SliderOnQueen * popcount(b & safe & attackedBy2[Us]);
+ score += SliderOnQueen * popcount(b & safe & attackedBy2[Us]) * (1 + queenImbalance);
}
if (T)