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## Re: [Bug-gnubg] Huge evaluation difference

 From: Philippe Michel Subject: Re: [Bug-gnubg] Huge evaluation difference Date: Wed, 20 Mar 2019 23:10:21 +0100 User-agent: Mutt/1.11.4 (2019-03-13)

On Wed, Mar 20, 2019 at 11:40:41AM +0100, ?ystein Sch?nning-Johansen wrote:

> I managed to calculate the gammon saving probability of the posted position
> in a few minutes using about 15GB of memory. (I also have a slower version
> of the tool that uses sparse matrices to store the probabilities, but I did
> not try that today)
>
> 2000036300001 2231
> #off:  0  board: 2----3|63----|1-----|-----
>         chk(bb): x----x|xx----|x-----|----- back: 13 #out: 10 #cross: 26
> #off:  7  board: 2231--|------|------|-----
>         chk(bb): xxxx--|------|------|----- back:  4 #out:  0 #cross:  8
> Cubeless prob. of saving gammon: 0.129424

This is not directly comparable with the numbers below since your number
is before the roll. Can you compute it from the other side (probability
of winning a gammon) for the first 2 or 3 choices of playing a 61 roll ?

> >     1. Cubeful 2-ply    13/6                         Eq.: -2.201
> >        0.000 0.000 0.000 - 1.000 0.913 0.000
> >         2-ply cubeful prune [world class]
> >     2. Cubeful 2-ply    8/2 7/6                      Eq.: -2.204 (-0.003)
> >        0.000 0.000 0.000 - 1.000 0.915 0.000
> >         2-ply cubeful prune [world class]
> >     3. Cubeful 2-ply    7/6 7/1                      Eq.: -2.213 (-0.013)
> >        0.000 0.000 0.000 - 1.000 0.923 0.000
> >         2-ply cubeful prune [world class]
> >     4. Cubeful 2-ply    13/12 8/2                    Eq.: -2.234 (-0.034)
> >        0.000 0.000 0.000 - 1.000 0.939 0.000
> >         2-ply cubeful prune [world class]
> >     5. Cubeful 2-ply    13/12 7/1                    Eq.: -2.240 (-0.039)
> >        0.000 0.000 0.000 - 1.000 0.943 0.000
> >         2-ply cubeful prune [world class]
> >     6. Cubeful 2-ply    13/7 6/5                     Eq.: -2.294 (-0.093)
> >        0.000 0.000 0.000 - 1.000 0.984 0.000
> >         2-ply cubeful prune [world class]