HCha/Stockfish
1
0
Fork 0
mirror of https://github.com/HChaZZY/Stockfish.git synced 2025-12-22 18:17:02 +08:00
Code Issues Packages Projects Releases Wiki Activity

Extend irreversible moves

Browse Source 
if these are ttMoves and played in positions with a high value of the rule50 counter. The unusual extension of 2 is safe in this context as awarding it will reset the rule50 counter, making sure it is awarded very rarely in a search path.

This patch partially addresses https://github.com/official-stockfish/Stockfish/issues/2620 as it should make it less likely to play a move that resets the counter, but that is worse than alternative moves after a slightly deeper search.

passed STC:
LLR: 2.96 (-2.94,2.94) {-0.50,1.50}
Total: 71658 W: 13840 L: 13560 D: 44258
Ptnml(0-2): 1058, 7921, 17643, 8097, 1110
https://tests.stockfishchess.org/tests/view/5e90d0f6754c3424c4cf9f41

passed LTC:
LLR: 2.94 (-2.94,2.94) {0.25,1.75}
Total: 85082 W: 11069 L: 10680 D: 63333
Ptnml(0-2): 459, 6982, 27259, 7393, 448
https://tests.stockfishchess.org/tests/view/5e917470af0a0143109dc341

closes https://github.com/official-stockfish/Stockfish/pull/2623

Bench: 4432822
This commit is contained in:
Joost VandeVondele
2020-04-10 21:53:00 +02:00
parent 6596f0eac0
commit 2c5f0efa13
1 changed files with 6 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

6
src/search.cpp
View File

@@ -1110,6 +1110,12 @@ moves_loop: // When in check, search starts from here
if (type_of(move) == CASTLING) if (type_of(move) == CASTLING)
extension = 1; extension = 1;
// Late irreversible move extension
if ( move == ttMove
&& pos.rule50_count() > 80
&& (captureOrPromotion || type_of(movedPiece) == PAWN))
extension = 2;
// Add extension to new depth // Add extension to new depth
newDepth += extension; newDepth += extension;