bob wrote:
700-1500 Elo is certainly meaningless. Where does that come from? 20 years ago the assumption was that 2800 was the upper bound on Elo. That seems to have bitten the big banana. The only thing that bounds Elo is that the best player will be hard-pressed to get more than 800 above the second-best player. But then the second best can get to 800 below the 3rd.
Well, I will show how that is "meaningless". Some 2-3 years ago I computed the estimate of the rating of the perfect engine as limiting ELO of Houdini 3 to infinite number of nodes (time control). Duncan refers to that post of mine. Today I repeated with thousands of games this estimate with Komodo 9.3 to infinite time control (doubling in time). I guess you consider ELO gain per doubling as "close to 70 ELO points", which is totally misleading, and the diminishing returns are thought by you as "hard to measure".
My today's tests:
First doubling: 10s+0.1s vs 5s+0.05s -- 148 ELO points
Second doubling: 20s + 0.2s vs 10s+0.1s -- 128 ELO points
Third doubling: 40s+0.4s vs 20s+0.2s -- 110 ELO points
Other data:
Close to eighth doubling -- CEGT 40/20' -- 65 ELO points
Close to ninth doubling -- CCRL 40/40' -- 55 ELO points
Diminishing returns are very visible here. I fitted these results with the relevant curve. Here is the plot of ELO gain per doubling in time:
The red dots are not data, they are predictions, first for Larry's 45'+15'' on 24 cores level against humans in odds matches, for which Larry got as Komodo performing at 3250 FIDE ELO level, second red dot shows TCEC level of 150'+30'' on 24 faster cores. One sees that at those high levels the gain per doubling is below 40 ELO points.
The fit: the fitting curve chosen is relevant as I show. It is a/(1+b*(number of doublings)^c). {a,b,c} are parameters to fit, and {c} is the relevant exponent here. If {c} is between 0 and 1, then we do have diminishing returns, but the total ELO is unbounded for higher and higher number of doublings, therefore the rating of perfect engine is undetermined and high. If c>1, then the perfect engine has a definite limited rating which can be derived.
It turns out that the best fit is
c=1.56, which is significantly larger than 1, and
the ELO of the perfect engine can be computed and is not very high. I actually
derive this, it is not assumed.
Do you have a more relevant fitting expression? I assume only that diminishing gains are going to 0 gain per doubling to infinite number of doublings, and this is related to the draw ratio going to 100% to infinite time control (doublings). Do you have a more plausible model which shows that the draw ratio has in fact lower limit than 100%?
Having the fit, I can compute the ELO of the perfect engine by summing up all gains from doublings starting from established by Larry FIDE ELO 3250 (close to 13th doubling in time).
It is ~1300 ELO points above Larry's 24 core Komodo. Therefore, Komodo 9.3 shows a FIDE ELO of the perfect engines at about 3250+1300 =
4550 ELO points. CCRL rating would be 100-200 ELO points higher, as their rating is computer rating. And very close to 4800 CCRL I got 2-3 years ago with Houdini 3.
As you see, 700-1500 ELO points estimate for improvement over Komodo I gave previously is not meaningless at all, my model here is simple, robust, and consistent with earlier results (including one or two by Don Dailey). If you want to dismiss it, it's surely not by "we don't know" mantra, because it seems it is mostly you who "doesn't know".