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Re: OSR [Was: Re: [Bug-gnubg] call for cycles (unix/libux only for now)]
From: |
Joseph Heled |
Subject: |
Re: OSR [Was: Re: [Bug-gnubg] call for cycles (unix/libux only for now)] |
Date: |
Thu, 01 Aug 2002 09:35:58 +1200 |
Joern Thyssen wrote:
>
> > When cube > 1, My cube code estimates the equity by 'a * live + (1-a) *
> > dead'
> > For contact positions, the best empirical value I found is a = 0.7
>
> This is identical to gnubg (except that gnubg uses 0.68 for contact,
> 0.60 for BEAROFF1 and BEAROFF2, and some linear interpolation for
> CLASS_RACE).
>
> > For race, I developed another model
> >
> > a = M * P * I
> >
> > M = a magic scaler (0.0606)
> > P = average number of rolls to race end.
> > (Take the smaller value computed for the two players.)
> > I = redouble incentive
>
> It was something like that I was looking for.
>
> > P is obtained from a modified pip count. Wastage is accounted for by
> > adding 2.5 points for every checker on the 1 point, 2 for checkers on
> > the 2 point etc., and the total is divided by 8.16
>
> If 'a' is to be used with a OSR, the average number of rolls from the
> OSR or BEAROFF2 can be used.
>
> > I is 'G/L', where G (gain) is (equity after redouble - equity at
> > current cube) when he wins, and L is same when he loses. I tried to
> > capture the "eagerness" of the cube holder to redouble.
>
> So at -4, -5 with a centered cube:
>
Not exactly. Note the (When cube > 1) at the very beginning. This does not apply
for centered cube
> G = MWC(-2,-5) - MWC(-3,-5) ~= 75% - 66% = 9%
> L = MWC(-4,-4) - MWC(-4,-3) ~= 50% - 41% = 9%
>
> So I = 1 in this case. Also, for money I = 1.
>
> At -3, -4 the same calculation gives: I = 1.5
>
> I think this should be easy to implememt in gnubg as well.
>
For centered cube, I use 'a * live + (1-a)/2 * (dead-for-player1 +
dead-for-player-2)'
a = 0.65 is the best I know of.
I tried to improve this generic case for race and failed.
-Joseph