Why is Stockfish removing killer moves in move ordering ?

[Paul JF]

From this commit https://github.com/official-stockfish/S ... 790ee56176, Stockfish stops using killer moves in move ordering. Why ? I thought it was in important piece of move ordering, am I right ? Even is Stockfish can manage to have few more wins against itself, it is something "usual" to have killer moves, I do not understand why they remove it.

[shawn]

It was removed because it accounts for many lines of code but doesn't account for any strength. IMO the reason that it doesn't gain elo anymore is both due to the improvements in history heuristics over the years and advancements in NNUE making the minor slowdown of removing one movepicker stage even more negligible.

[Viz]

From this commit https://github.com/official-stockfish/S ... 790ee56176, Stockfish stops using killer moves in move ordering. Why ? I thought it was in important piece of move ordering, am I right ? Even is Stockfish can manage to have few more wins against itself, it is something "usual" to have killer moves, I do not understand why they remove it.

because they don't do anything any longer (strength-wise)? No matter how "usual" smth is if it is useless stockfish will remove it. And it was done before a lot of times.
For example IID was a "usual" thing but completely useless once you get to 3000 CCRL strength. Or check extensions. Or (a lot of other things).

[AndrewGrant]

The passage of time necessitates revisiting previous decisions.

[mar]

For example IID was a "usual" thing but completely useless once you get to 3000 CCRL strength. Or check extensions. Or (a lot of other things).

I wonder since by removing check extensions the engine will be severely crippled tactically

[AndrewGrant]

For example IID was a "usual" thing but completely useless once you get to 3000 CCRL strength. Or check extensions. Or (a lot of other things).

I wonder since by removing check extensions the engine will be severely crippled tactically

I wonder if <the opposite of the thing that was measured to not happen in order to make the decision> will happen

[Viz]

For example IID was a "usual" thing but completely useless once you get to 3000 CCRL strength. Or check extensions. Or (a lot of other things).

I wonder since by removing check extensions the engine will be severely crippled tactically

I wonder if severely tactically crippled engine would be able to pass non-reg SPRT vs severely better tactical engine.
My guess would be no, since it only means that this doesn't happen.

[mar]

I wonder if <the opposite of the thing that was measured to not happen in order to make the decision> will happen

I still remember a game a couple of years ago where SF lost to Weiss in TCEC exactly due to missing some tactics - so it may happen

also some people use engines for analysis

elo is not the best way to measure tactical blindness since it correllates with that works most of the time

[Ciekce]

I wonder since by removing check extensions the engine will be severely crippled tactically

source: I made it up

[AndrewGrant]

I wonder if <the opposite of the thing that was measured to not happen in order to make the decision> will happen

I still remember a game a couple of years ago where SF lost to Weiss in TCEC exactly due to missing some tactics - so it may happen

also some people use engines for analysis

elo is not the best way to measure tactical blindness since it correllates with that works most of the time

you'll be hard pressed to show that one patch has a material impact and not just chance, on a particular position.
nothing you wrote is based in any fact or science, where as the removal of the concept is. So I defer to science.