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Re: [Bug-gnubg] Cubeless equity in cubeful rollouts
From: |
Christian Anthon |
Subject: |
Re: [Bug-gnubg] Cubeless equity in cubeful rollouts |
Date: |
Mon, 15 Dec 2008 09:59:33 +0100 |
Without consulting the code, I'm guessing the following: For money
games the cubeless equity is a fairly well defined thing, as the
relative cost of a point, gammon or backgammon is independent of the
cube value. For matches it is different. Suppose the there is a
double/take in a game in your example game. Now, should the cubeless
equity of such a game be calculated with the cube at two or one.
Neither is probably a very good idea, but I'm guessing that the
evaluation is done with the cube at two, which explains the difference
in numbers that you are observing.
The bottom line: don't use the CL equities for matches.
Christian.
On Sun, Dec 14, 2008 at 7:59 PM, <address@hidden> wrote:
> I have a question concerning the cubeless equity derived from cubeful
> rollouts
>
>
>
> Date: Dezember 14, 2008
> Move number 3: X to play 32
>
> GNU Backgammon Position ID: mGdrBgDLzInBAA
> Match ID : cImpACAAAAAA
> +24-23-22-21-20-19------18-17-16-15-14-13-+ O: somebody
> | O O | | X O O O O X | 2 points
> | O O | | X O O O X |
> | O | | |
> | O | | |
> | | | |
> | |BAR| |v 5 point match (Cube: 1)
> | | | |
> | | | |
> | | | X |
> | X X X | | X O | Rolled 32
> | X X X X | | X X O | 0 points
> +-1--2--3--4--5--6-------7--8--9-10-11-12-+ X: You
> Pip counts: O 124, X 120
>
> * You moves 18/15*/13
>
>
> This is a cubeless rollout result:
>
> 1. Rollout 8/6 8/5 Eq.: -0,008
> 0,498 0,015 0,000 - 0,502 0,014 0,001 CL -0,008
> [0,001 0,001 0,000 - 0,001 0,001 0,000 CL 0,003]
> Full cubeless rollout with var.redn.
> 1296 games, Mersenne Twister dice gen. with seed 812588963 and
> quasi-random dice
> Play: 0-ply cubeful prune
> Cube: 0-ply cubeful prune
> 2. Rollout 18/15*/13 Eq.: -0,134 ( -0,127)
> 0,464 0,174 0,005 - 0,536 0,174 0,009 CL -0,134
> [0,002 0,002 0,001 - 0,002 0,002 0,001 CL 0,006]
> Full cubeless rollout with var.redn.
> 1296 games, Mersenne Twister dice gen. with seed 812588963 and
> quasi-random dice
> Play: 0-ply cubeful prune
> Cube: 0-ply cubeful prune
>
>
> And this is a cubeful rollout result:
>
> 1. Rollout 18/15*/13 Eq.: +0,031
> 0,465 0,176 0,006 - 0,535 0,176 0,015 CL -0,025 CF +0,031
> [0,002 0,002 0,001 - 0,002 0,002 0,002 CL 0,006 CF 0,012]
> Full cubeful rollout with var.redn.
> 1296 games, Mersenne Twister dice gen. with seed 812585055 and
> quasi-random dice
> Play: 0-ply cubeful prune [expert]
> Cube: 0-ply cubeful prune [expert]
> 2. Rollout 8/6 8/5 Eq.: -0,009 ( -0,040)
> 0,500 0,017 0,000 - 0,500 0,014 0,001 CL -0,001 CF -0,009
> [0,001 0,001 0,000 - 0,001 0,001 0,000 CL 0,003 CF 0,006]
> Full cubeful rollout with var.redn.
> 1296 games, Mersenne Twister dice gen. with seed 812585055 and
> quasi-random dice
> Play: 0-ply cubeful prune [expert]
> Cube: 0-ply cubeful prune [expert]
>
>
>
> I know why we should not expect the w/g/bg breakdowns to be the same (with
> the cubeful rollout being truncated in case of a double/pass), but anyway in
> this case they are close. What I don't understand at all is why the cubeless
> equity of 18/15*/13 differs so much in the cubeful and in the cubeless
> rollout.
>
>
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