Do more reductions for late quiet moves in case of consecutive fail highs.
authorVizvezdenec <Vizvezdenec@gmail.com>
Sat, 17 Oct 2020 11:40:10 +0000 (13:40 +0200)
committerJoost VandeVondele <Joost.VandeVondele@gmail.com>
Sun, 18 Oct 2020 11:54:28 +0000 (13:54 +0200)
commit560c776397483feaaa0deb5b666f46ff3f5b655f
tree4a85409d14f446afa7109e74afc66dc927346628
parent281d520cc2bb0123efd230fce45119b57f0bae0d
Do more reductions for late quiet moves in case of consecutive fail highs.

Idea of this patch can be described as following - in case we have consecutive fail highs and we reach late enough moves at root node probability of remaining quiet moves being able to produce even bigger value than moves that produced previous cutoff (so ones that should be high in move ordering but now they fail to produce beta cutoff because we actually reached high move count) should be quiet small so we can reduce them more.

passed STC
LLR: 2.94 (-2.94,2.94) {-0.25,1.25}
Total: 53392 W: 5681 L: 5474 D: 42237
Ptnml(0-2): 214, 4104, 17894, 4229, 255
https://tests.stockfishchess.org/tests/view/5f88501adcdad978fe8c527e

passed LTC
LLR: 2.94 (-2.94,2.94) {0.25,1.25}
Total: 59136 W: 2773 L: 2564 D: 53799
Ptnml(0-2): 30, 2117, 25078, 2300, 43
https://tests.stockfishchess.org/tests/view/5f884dbfdcdad978fe8c527a

closes https://github.com/official-stockfish/Stockfish/pull/3184

Bench: 4066972
src/search.cpp
src/thread.h