Tweak null move pruning conditions
authorStefan Geschwentner <stgeschwentner@gmail.com>
Tue, 8 May 2018 17:03:22 +0000 (19:03 +0200)
committerStéphane Nicolet <cassio@free.fr>
Tue, 8 May 2018 21:31:55 +0000 (23:31 +0200)
commitde0889612f93d021e0754a201ce751fe05d8cb2c
treeb7e2b75b21066a4bbf5fe63e6060b3cad77c2b95
parent6634f41ac9e76fe623dd36d312b6955ab2c66a4f
Tweak null move pruning conditions

Allow null move pruning only if last stat score < 30000.

Passed STC:
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 12653 W: 2641 L: 2454 D: 7558
http://tests.stockfishchess.org/tests/view/5af1d8830ebc5968e6523edb

Passed LTC:
LLR: 2.97 (-2.94,2.94) [0.00,5.00]
Total: 19782 W: 3072 L: 2878 D: 13832
http://tests.stockfishchess.org/tests/view/5af1ee8c0ebc5968e6523ee4

Ideas for further work:

• Tune the stat score threshold.
• Try depth based stat score threshold.
• Try stat score condition for other prunings.

Closes https://github.com/official-stockfish/Stockfish/pull/1589

Bench: 5088156
src/search.cpp