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Re: FW: [Bug-gnubg] Update: Checkerplay vs cube decision errors
From: |
Joachim Matussek |
Subject: |
Re: FW: [Bug-gnubg] Update: Checkerplay vs cube decision errors |
Date: |
Wed, 19 May 2004 21:28:22 +0200 |
address@hidden schrieb am 19.05.04 20:14:23:
>
> Hi,
>
> Apart from noticing the misspelling of my name I have more comments:
>
Sorry if I misspelled your name. But I read my item several times. Did not find
it.
> Since chequer errors and cube errors really have different "units" the
> ratio of the coefficients a2 and b is meaningless.
>
> A meaningful measure is:
>
> M = a2(N)*EPM / b(N)*EPC
>
> M represents ratio of rating points lost due to chequer error adn cube
> error. Clearly it is player dependent. For me it is usually 10 in actual
> games I play.
This was not what I was talking about.
> Now in the article this is rewritten in the form of Eq. 5. The table
> below Eq. 5 plots something undefined but I guess it is
>
> (a2(N)/UFM(N))/(b(N)/UFC)
>
> with UFM # unforced moves and UFC # unforced cubes as obtained from
> rollout.
Sorry about that. I did not explain these expressions well.
Checker error coefficient = a2(N)/(No. of unforced moves)
Cube error coefficient = b(N)/(No. of close or actual cube decisions)
Checker error/Cube error ratio = (a2(N)/(No. of unforced moves)/(b(N)/(No. of
close or actual cube decisions)
I am not talking about unforced cube decisions because this would mean _all_
cube decision. I am talking of close or actual cube decisions as defined by
GNUBG.
> This is the ratio of the coefficients of a bilinear fit to total error
> rates of chequer and cube play. It is not clear to me this is really a
> better measure than a2/b. We still have the fact that cube decisions are
> really of a different kind than chequer play decisions even though both
> can be expressed in equity losses.
> I don't understand the ssecond paragraph of the "Results". If the cutoff
> for actual cube decision is decreased to .05 the # of actual cube
> decision goes down and the coefficient b(N) will also go down (it was
> measured assuming a fixed cutoff) so nothing changes.
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.
> In the 3d paragraph I read "... doubtful to clain cube error were
> less..". I don't see any arguments that support that claim.
>
> The opposite statement "cube errors are less important than chequer
> errors" has no rigorous meaning either. It just seems in practice that
> the rating points you lose due to cube errors are much less than the
> loss due to chequer play.
Some players concluded from reading your article that cube error were less
important. You didnĀ“t claim that.
>
> Kees
> --
I hope this discussion will stay friendly. I am just a backgammon player who
wants to understand this game.
Joachim Matussek
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