!! latest version !!Windows x64 for Haswell CPUsWindows x64 for modern computersWindows x64Windows 32Linux x64 for Haswell CPUsLinux x64 for modern computersLinux x64Author: 31m059
Date: Thu Dec 27 21:38:31 2018 +0100
Timestamp: 1545943111
Always initialize and evaluate king safety
Recent tests by @xoto10, @Vizvezdenec, and myself seemed to hint that Elo could
be gained by expanding the number of cases where king safety is applied. Several
users (@Spliffjiffer, @Vizvezdenec) have anticipated benefits specifically in
evaluation of tactics. It appears that we actually do not need to restrict the
cases in which we initialize and evaluate king safety at all: initializing and
evaluating it in every position appears roughly Elo-neutral at STC and possibly
a substantial Elo gain at LTC.
Any explanation for this scaling is, at this point, conjecture. Assuming it is
not due to chance, my hypothesis is that initialization of king safety in all
positions is a mild slowdown, offset by an Elo gain of evaluating king safety
in all positions. At STC this produces Elo gains and losses that offset each
other, while at longer time control the slowdown is much less important, leaving
only the Elo gain. It probably helps SF to explore king attacks much earlier in
search with high numbers of enemy pieces concentrating but not essentially attacking
king ring.
Thanks to @xoto10 and @Vizvezdenec for helping run my LTC!
Closes
https://github.com/official-stockfish/Stockfish/pull/1906 STC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 35432 W: 7815 L: 7721 D: 19896
Elo +0.92http://tests.stockfishchess.org/tests/view/5c24779d0ebc5902ba131b26 LTC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 12887 W: 2217 L: 2084 D: 8586
Elo +3.59http://tests.stockfishchess.org/tests/view/5c25049a0ebc5902ba132586 Bench: 3163951
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How to continue from there?
* Next step will be to tune all the king danger terms once more after that :-)