More random draw evaluations
authorJoost VandeVondele <Joost.VandeVondele@gmail.com>
Fri, 20 Sep 2019 14:33:57 +0000 (16:33 +0200)
committerStéphane Nicolet <cassio@free.fr>
Mon, 23 Sep 2019 05:29:00 +0000 (07:29 +0200)
commit770c8d92f3886d11ae88afef13f6552f9132a714
tree9469b496070fc154c084b374c174e7cc7a6e207a
parent7e4c3256aab178f303578b4c4a31c59d43421640
More random draw evaluations

Use the randomized draw function value_draw() also for draw evalutions.

This extends the earlier commit
https://github.com/official-stockfish/Stockfish/commit/97d2cc9a9c1c4b6ff1b470676fa18c7fc6509886
which did this only for 3folds.

As in that case, this test was yellow at STC and LTC, but green at VLTC,
indicative of the fact that the higher the drawrate, the more likely this
idea is beneficial.

STC:
LLR: -2.96 (-2.94,2.94) [0.50,4.50]
Total: 83573 W: 18584 L: 18335 D: 46654
http://tests.stockfishchess.org/tests/view/5d84e44d0ebc5971531d4f94

LTC:
LLR: -2.96 (-2.94,2.94) [0.00,3.50]
Total: 92252 W: 15240 L: 15160 D: 61852
http://tests.stockfishchess.org/tests/view/5d865dd90ebc5971531d68e1

VLTC: 120+1.2 @ 2th
LLR: 2.96 (-2.94,2.94) [0.00,3.50]
Total: 51902 W: 7323 L: 7028 D: 37551
http://tests.stockfishchess.org/tests/view/5d8763620ebc595f57c22b15

Closes https://github.com/official-stockfish/Stockfish/pull/2321

Bench: 3441237
src/search.cpp