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Allow RQ through pieces. Bench: 3415326 (#2153)

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We evaluate defended and unsafe squares for a passed pawn push based on friendly and enemy rooks and queens on the passed pawn's file. Prior to this patch, we further required that these rooks and queens be able to directly attack the passed pawn. However, this restriction appears unnecessary and worth almost exactly 0 Elo at LTC.

The simplified code allows rooks and queens to attack/defend the passed pawn through other pieces of either color.

STC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 29019 W: 6488 L: 6381 D: 16150
http://tests.stockfishchess.org/tests/view/5cdcf7270ebc5925cf05d30c

LTC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 54224 W: 9200 L: 9133 D: 35891
http://tests.stockfishchess.org/tests/view/5cddc6210ebc5925cf05eca3

Bench: 3415326
This commit is contained in:
31m059 2019-05-17 07:38:23 -04:00 • committed by Marco Costalba
parent 2985a6b5d7
commit bf6b647a1a
1 changed files with 1 additions and 1 deletions
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2
src/evaluate.cpp
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@ -649,7 +649,7 @@ namespace {
// in the pawn's path attacked or occupied by the enemy.
defendedSquares = unsafeSquares = squaresToQueen = forward_file_bb(Us, s);
bb = forward_file_bb(Them, s) & pos.pieces(ROOK, QUEEN) & pos.attacks_from<ROOK>(s);
bb = forward_file_bb(Them, s) & pos.pieces(ROOK, QUEEN);
if (!(pos.pieces(Us) & bb))
defendedSquares &= attackedBy[Us][ALL_PIECES];