Shallow depth pruning on NonPV advanced pawn push
authorMiguel Lahoz <miguel_lahoz@protonmail.com>
Sun, 10 Nov 2019 09:49:06 +0000 (17:49 +0800)
committerStéphane Nicolet <cassio@free.fr>
Tue, 12 Nov 2019 00:36:06 +0000 (01:36 +0100)
commit9ab2590963b029092a378c7a69d1c80c43999db8
treefdf82634a124aec92680e02e231d220531906f4d
parent44b6697f19ed45a6fb3f542acc83fc5d7111f375
Shallow depth pruning on NonPV advanced pawn push

Usually advanced pawn pushes are not considered in shallow depth pruning
because it is risky to do so with possible promotions near the horizon.
However, this heuristic is not also beneficial on NonPV nodes since we
can afford to take slightly more risk on less important nodes.

STC:
LLR: 2.95 (-2.94,2.94) [-1.50,4.50]
Total: 54530 W: 11955 L: 11686 D: 30889
http://tests.stockfishchess.org/tests/view/5dc7dda30ebc5902ea57efd0

LTC:
LLR: 2.95 (-2.94,2.94) [0.00,3.50]
Total: 77336 W: 12786 L: 12399 D: 52151
http://tests.stockfishchess.org/tests/view/5dc8050d0ebc5902ea57f491

Closes https://github.com/official-stockfish/Stockfish/pull/2408

Bench: 4422068
src/search.cpp