Rollouts

 Cubeless vs centered-cube rollouts

 From: Ron Karr Address: karr@best.com Date: 22 December 1997 Subject: Re: Difference and value of "cubeless" vs. "centered" roll outs Forum: rec.games.backgammon Google: 349EB00F.1A5B@best.com

```> My questions concern the terms "centered" and "cubeless" in the equity
> evaluations.
>
> 1. Am I correct in assuming that "cubeless" means that the game is
> played to completion with no doubling by either side?

Yes

> 2. Am I correct in assuming that "centered" means that the cube is
> available for either side during the roll out?

Yes

> 3. Why are both "cubeless" and "centered" roll outs valuable in
> determining whether to double?  Is a different type of information
> gleaned from each of them?

Yes, you get different information.  Cubeless tells you the results when
the game is played to the end.  "Centered cube" means that both players
have access to the cube; when either player's equity gets to a point
greater than the "settlement limit" (usually set at .55), that player is
counted as winning a single game.

To determine whether to double (according to the level 5 rollouts), you
also need to look at the figures for "player not on roll owns cube".
You multiply that figure times 2 (because the guy being doubled owns a
2-cube), and if it's greater (for the doubler) than the center cube
equity, then doubling is correct.  (And it's a pass if the "player not
on roll owns cube" equity is worse than -.5).

(If you're looking at redoubles, then you use "player on roll owns cube"

Ron
```

### Rollouts

Cautionary tale  (Kit Woolsey, Sept 1995)
Combining rollouts  (Gregg Cattanach+, Dec 2003)
Confidence intervals  (Bob Koca, Nov 2010)
Confidence intervals  (Timothy Chow, May 2010)
Confidence intervals  (Gerry Tesauro, Feb 1994)
Cubeless vs centered-cube rollouts  (Ron Karr, Dec 1997)
Duplicate dice  (David Montgomery, June 1998)
How reliable are rollouts?  (David Montgomery, Aug 1999)
Level-5 versus level-6 rollouts  (Michael J. Zehr, June 1998)
Level-5 versus level-6 rollouts  (Chuck Bower, Aug 1997)
Positions with inaccurate rollouts  (Douglas Zare, Oct 2002)
Reporting results of rollouts  (David Montgomery, June 1995)
Rollout settings  (Lokicol+, Apr 2010)
Settlement limit  (Michael J. Zehr, Apr 1998)
Settlement limit  (Kit Woolsey, Dec 1997)
Settlement limit in races  (Alexander Nitschke, Dec 1997)
Some guidelines  (Kit Woolsey, Apr 1996)
Standard error and JSD  (rambiz+, Feb 2011)
Standard error and JSD  (Stick+, Oct 2007)
Systematic error  (Chuck Bower, Oct 1996)
Tips for doing rollouts  (Douglas Zare, June 2002)
Truncated rollouts  (Gregg Cattanach, Oct 2002)
Truncated rollouts: pros and cons  (Jason Lee+, Jan 2006)
What is a rollout?  (Gregg Cattanach, Dec 1999)

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