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## Re: [Bug-gnubg] R.Janowski paper "Take-Points in Money Games"

 From: Christian Anthon Subject: Re: [Bug-gnubg] R.Janowski paper "Take-Points in Money Games" Date: Mon, 2 Mar 2009 16:52:03 +0100

```On Mon, Mar 2, 2009 at 10:02 AM, Massimiliano Maini

I believe you are right, but possibly janowski is as well. Take a look
a this thread http://www.bkgm.com/rgb/rgb.cgi?view+965, it might make
you wiser.

Christian.

>
> Hi all,
>
> I was reading Rick Janowski's article "Take-Points in Money Games" (you can
> find it here:
> http://www.msoworld.com/mindzine/news/classic/bg/cubeformulae.pdf). I didn't
> dig into the
> refined general mode, but in the general model (the one used by gnubg) I get
> a different
> expression for the centered cube equity.
>
> The reasoning in Janowski's paper seems to be (if I got it right):
>
> 1) We know the expressions of dead cube equity and dead cube take/cash
> points.
>
> 2) We compute (as shown in Appendix 5, par. 1) the live cube take and cash
> point.
>
> 3) We compute live cube equities expressions:
>         3.1) Live cube equity owning the cube can be computed as linear
> interpolation
>         between the points (p=0%,E=-Cv*L) and (p=TP%,E=-Cv/2)
>         3.2) Live cube equity with unavailable cube can be computed as
> linear interpolation
>         between the points (p=CP%,E=Cv/2) and (p=100%,E=Cv*W)
>         3.3) Live cube equity with centered cube can be computed as linear
> interpolation
>         between the points (p=TP%,E=-Cv) and (p=CP%,E=Cv)
> 4) At this point we can deduce the live initial double point (No Jacoby),
> redouble point
> and too good point (I don't care yet for beaver/racoon points and initial
> double point
> with Jacoby rule in use).
>
> Up to this point, I get exactly the same results.
>
> 5) We compute general cube equities. Here's where it gets fuzzy. I think
> that general cube
> equities are/should be computed by linear interpolation between dead and
> live equities (that's
> even what's written in gnubg manual), with the cube life index x being
> between 0 and 1:
>         5.1) Egeneral_own  = Edead*(1-x) + Elive_own*x  : developing this I
> get the same result
>         5.2) Egeneral_unav = Edead*(1-x) + Elive_unav*x : developing this I
> get the same result
>         5.3) Egeneral_cen  = Edead*(1-x) + Elive_cen*x  : here I get a
> different result
>
> 6) We compute the general TP, IDP, RDP, CP, TGP by definition (i.e. with
> equations involving
> the equities expressions). Of course, with identical own and unav general
> equities, I get the
> same expressions for general TP, RDP, CP and TGP. But with a different
> expression for the
> general centered equity I naturally get a different expression for the IDP
> (initial double
> point, I only checked the No-Jacoby case).
>
> What looks strange to me is that Janowski's expression of the general
> centered cube equity
> is not even linear in x ... Anybody with an idea ?
>
> MaX.
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>
>

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