Forum Archive :
Rollouts
A rollout is playing a game out from a specific position many times and
recording the results. This used to be done by hand in the 'old' days, but
now we can use JellyFish and Snowie to do it. Many of Snowie's rollout
options 'truncate' the rollout in various ways and use other methods to
shorten the actual amount of moves that must be analyzed. Often Snowie
will play out the position 1296, 3888 times (or other numbers of that
scale) and add up all the wins and losses (or in the case of truncated
rollouts, add up the equity of the resulting positions) to see what the
position is actually worth.
One of the biggest features of the new Snowie 3.0, is that all rollouts and
evaluations are played with a live cube, unlike Snowie 2.0 (which had that
option, but only on specific settings).
Unless the position is quite complicated (deep backgames or containment
positions especially), Snowie's 3-ply evaluation is very often very close
to a rollout result, so it is usually only needed when deep analysis of a
specific position is required. Also, some experts won't trust some
specific types of Snowie rollouts, because they believe Snowie isn't
playing the position "correctly". Some rollout setups can take days, but
standard ones can be done in 5-10 minutes.
--
Gregg Cattanach
Zox at GamesGrid, VOG, Zone
http://gateway.to/backgammon
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Rollouts
- Advice (David Montgomery, Apr 1996)
- 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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