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Re: [Bug-gnubg] I'm a bit confused
From: |
Joern Thyssen |
Subject: |
Re: [Bug-gnubg] I'm a bit confused |
Date: |
Tue, 29 Jul 2003 21:13:40 +0000 |
User-agent: |
Mutt/1.4.1i |
On Tue, Jul 29, 2003 at 04:19:01PM -0300, Albert Silver wrote
>
> I'm trying to understand why move 3 is a -0.147 blunder when its wins
> are only 0.1% less, it scores more gammons, and loses less gammons and
> backgammons.
You can't rely on the cubeless numbers when doing a cubeful rollout.
If the game reaches a "double, pass" then the rollout is truncated with
a cubeful equity of +1 (or -1) and gnubg uses the cubeless numbers from
the cube decision (which is 0-ply in your case).
Worst case scenario: you're on roll in a position where you'll be
doubled out no matter what you roll. If you do a 0-ply cubeful rollout
then the cubeful equity is -1 and the cubeless gwc is identical to a
1-ply evaluation even though you've selected 1,679,616 trials.
For this very reason I've been on the verge of removing the output
wins/gammons/backgammons from all evaluations and rollouts! Your
question is not the first, and certainly not the last!
Try doing a full cubeless rollout. I imagine that you'll see totally
different numbers. Your numbers may also be an indication of 0-ply not
being good enough for the cube decision, so you can try a rollout with
0-ply chequerplay and 2-ply cube play.
You may see similar problems for evaluations as well, but as evaluations
are never truncated then the problem is usually not so large.
Jørn
- [Bug-gnubg] I'm a bit confused, Albert Silver, 2003/07/29
- Re: [Bug-gnubg] I'm a bit confused, Jim Segrave, 2003/07/29
- Re: [Bug-gnubg] I'm a bit confused,
Joern Thyssen <=
- Re: [Bug-gnubg] I'm a bit confused, Joseph Heled, 2003/07/29
- Re: [Bug-gnubg] I'm a bit confused, Jim Segrave, 2003/07/29
- RE: [Bug-gnubg] I'm a bit confused, Albert Silver, 2003/07/29
- Re: [Bug-gnubg] I'm a bit confused, Joern Thyssen, 2003/07/30
- Re: [Bug-gnubg] I'm a bit confused, Jim Segrave, 2003/07/30
- Re: [Bug-gnubg] I'm a bit confused, Joern Thyssen, 2003/07/30
- Re: [Bug-gnubg] I'm a bit confused, Jim Segrave, 2003/07/30
- Re: [Bug-gnubg] I'm a bit confused, Joern Thyssen, 2003/07/30
- Re: [Bug-gnubg] I'm a bit confused, Joern Thyssen, 2003/07/30
- Re: [Bug-gnubg] I'm a bit confused, Jim Segrave, 2003/07/30