It appears as though removing squares that are already attacked
by our pawns can be removed.
STC
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 51242 W: 11503 L: 11440 D: 28299
http://tests.stockfishchess.org/tests/view/
5b58b5a40ebc5902bdb88f52
LTC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 35246 W: 6063 L: 5966 D: 23217
http://tests.stockfishchess.org/tests/view/
5b58f8e20ebc5902bdb8959b
How to continue after this patch: there is now a slight semantic
overlap between the ThreatByPawnPush and the ThreatBySafePawn bonuses,
so hand-tuning either of these, or both at the same time, is natural.
Closes https://github.com/official-stockfish/Stockfish/pull/1702
Bench
4734881
& (attackedBy[Us][ALL_PIECES] | ~attackedBy[Them][ALL_PIECES]);
// Bonus for safe pawn threats on the next move
- b = pawn_attacks_bb<Us>(b)
- & pos.pieces(Them)
- & ~attackedBy[Us][PAWN];
-
+ b = pawn_attacks_bb<Us>(b) & pos.pieces(Them);
score += ThreatByPawnPush * popcount(b);
// Bonus for threats on the next moves against enemy queen