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[Bug-gnubg] Re: Checkerplay vs cube decision errors
From: |
kvandoel |
Subject: |
[Bug-gnubg] Re: Checkerplay vs cube decision errors |
Date: |
Sat, 22 May 2004 18:59:27 +0200 (CEST) |
On Fri, 21 May 2004, Joachim Matussek wrote:
> > > Should be self-explaing now. It is not b(N) which goes down. It is
> > > b(N)/(No. of close or actual cube decisions) which goes down.
> > I don't get it. If you reduce the cutoff "No. of close or actual cube
> > decisions" goes down. b(N) also goes down so the ratio remains the same.
> you seem to be right.
> It seems that (a2(N)/(No. of unforced moves))/(b(N)/(No. of close or
>actual cube decisions)) only depends on the match length. It ranges
>from 3.38 to 2.56 within the chosen examples.
> Thus we should be able to conclude that checkerplay errors and cube
>decision errors have different weights when calculating a player?s
>rating. It also means that they have different influence on the outcome
>of matches.
> Yes?
> No?
> If yes, why?
> Isn?t our term and calculation of cube decision errors flawed? Should
>we estimate cube errors in a different way?
The idea behind my simulations was to just consider the chequer and
error rates, however computed, as probes into the system, and see how
they correlate to the actual rating of players as obtained by estimating
their playing strengths statistically from the luck adjusted match
results.
The formula that's currently programmed into GNUBG to translate error
rates into rating point losses over a match is a good empirical fit to
the data.
How to interpret the individual terms in the formula and if you can draw
any grand conclusions about the importance of chequerplay versus cube
decisions is less clear.
However, in practice, without exception, the number of rating points
lost due to chequer error (QLO) is always much larger than the number of
rating points lost due to cube errors (CLO), in a particular match.
(Well maybe if someone cubes after opponent opens 31 and then gets a
forced game with a closeout and no real chequer play you would see an
exception.) This seems to hold across all ratings, though the actual
ratio CQ = CLO/QLO is player dependent (and of course fluctuates a lot).
It seems reasonable to interpret CQ as the balance between chequer play
skill and cube handling skill of a player, CQ = 1 means the player is
equally skilled in both. In practice, for every human I've observed, CQ
is much larger than 1, of the order of 10.
We can conclude that chequer play is more important in the following
sense. Suppose there is a bg pill on the market. The red pill gives you
perfect chequer skills, the green pill gives you perfect cube handling
skills, but you can take only one pill at a time due to disastrous drug
interactions. Which pill should you take? Clearly the red pill for
almost everyone.
The small effect of cube errors on overall performance allso gives an
interesting perspective on the so-called "pip-counting" methods. It
follows that for almost everyone, learning to accurately pip-count is a
complete waste of time.
Kees