[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Bug-gnubg] Odd rollout results of classic reference position
From: |
Ned Cross |
Subject: |
Re: [Bug-gnubg] Odd rollout results of classic reference position |
Date: |
Sun, 18 May 2003 17:27:03 -0700 |
I think this would be a take if all of O's checkers were on the ace and 2
pts, and even perhaps with 2 on the 3 pt. I think it's the distribution
here that makes it a pass for O. Walter Trice had a good article on
1-checker closeouts in Gammon Village about a year or so ago.
http://www.gammonvillage.com/backgammon/news/article_display.cfm?resourceid=1182
I agree that it seems like X should be able to cash more games later by
retaining cube access. I've seen this show up with GNUBg in other positions
as well.
-Ned
----- Original Message -----
From: "ershaw" <address@hidden>
To: "GNUBackgammon bug reporting" <address@hidden>
Cc: "Ian Shaw" <address@hidden>
Sent: Sunday, May 18, 2003 8:22 AM
Subject: [Bug-gnubg] Odd rollout results of classic reference position
> Five off and one closed out is traditioanlly a take. A GnuBg rollout has
it
> as a pass. I've got no problem with that.
>
> What is odd is that the equit of No DOuble is greater than 1. How can this
> be? That would make it Too Good in a position where no gammons are
possible.
>
> This is yet another position where the doubler is seen to win more games
by
> doubling than by holding on to the cube. I would expect O to double X out
in
> some games if O has cube access. Therefore X ought to win less games if he
> gives up the cube. Something seems wrong. Is it me?
>
> --Ian
>
> GNU Backgammon Position ID: tw0AANp2dwAAAA
> Match ID : UQkAAAAAAAAA
> +24-23-22-21-20-19------18-17-16-15-14-13-+ O: gnubg
> O | O O O O | O | | 0 points
> O | O O O O | | |
> O | O | | |
> O | | | |
> O | | | |
> | |BAR| |v
> | | | |
> | | | |
> | X X X | | |
> | X X X X X X | | | On roll
> | X X X X X X | | | 0 points
> +-1--2--3--4--5--6-------7--8--9-10-11-12-+ X: user (Cube: 2)
>
> Cube analysis
> Rollout cubeless equity +0.584
>
> Cubeful equities:
> 1. Double, pass +1.000
> 2. Double, take +1.061 ( +0.048)
> 3. No double +1.013 ( +0.000)
> Proper cube action: Redouble, pass
> Rollout details:
> Player user owns 2-cube:
> 0.792 0.000 0.000 - 0.208 0.000 0.000 CL +0.584 CF +1.013
> [0.000 0.000 0.000 - 0.000 0.000 0.000 CL 0.001 CF +0.003]
> Player gnubg owns 4-cube:
> 0.795 0.000 0.000 - 0.205 0.000 0.000 CL +1.181 CF +1.061
> [0.001 0.000 0.000 - 0.001 0.000 0.000 CL 0.002 CF +0.003]
> Full cubeful rollout with var.redn.
> 1296 games, seed 1206724736 using quasi-random dice and Mersenne Twister
> Play and cube: 2-ply cubeful 100% speed [world class]
>
>
>
>
> _______________________________________________
> Bug-gnubg mailing list
> address@hidden
> http://mail.gnu.org/mailman/listinfo/bug-gnubg