Verified SEE pruning for capturing and checking moves.

Patch analyzes field after SEE exchanges concluded with a recapture by
the opponent:
if opponent Queen/Rook/King results under attack after the exchanges, we
consider the move sharp and don't prune it.

Important note:
By accident I forgot to adjust 'occupied' when the king takes part in
the exchanges.
As result of this a move is considered sharp too, when opponent king
apparently can evade check by recapturing.
Surprisingly this seems contribute to patch's strength.

STC:
https://tests.stockfishchess.org/tests/view/640b16132644b62c33947397
LLR: 2.96 (-2.94,2.94) <0.00,2.00>
Total: 116400 W: 31239 L: 30817 D: 54344
Ptnml(0-2): 350, 12742, 31618, 13116, 374

LTC:
https://tests.stockfishchess.org/tests/view/640c88092644b62c3394c1c5
LLR: 2.95 (-2.94,2.94) <0.50,2.50>
Total: 177600 W: 47988 L: 47421 D: 82191
Ptnml(0-2): 62, 16905, 54317, 17436, 80

closes https://github.com/official-stockfish/Stockfish/pull/4453

bench: 5012145
This commit is contained in:
pb00067
2023-03-20 08:56:44 +01:00
committed by Joost VandeVondele
parent 02e4697055
commit 24b37e4586
5 changed files with 37 additions and 17 deletions

View File

@@ -144,7 +144,7 @@ public:
void undo_null_move();
// Static Exchange Evaluation
bool see_ge(Move m, Value threshold = VALUE_ZERO) const;
bool see_ge(Move m, Bitboard& occupied, Value threshold = VALUE_ZERO) const;
// Accessing hash keys
Key key() const;