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Please explain "Rollouts"

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Dec 15, 1999, 3:00:00 AM12/15/99
Rollouts , statistically give the result of any number of rolls at any
given position. Therefore if you were at a given position and question
whether a double was appropriate or a gammon was possible you could
"rollout" the position and calculate all the possiblities.

Hope this was of help..


> Could someone please explain the concept of "rollouts" to the few of
> us who really do not know. I was visiting the Snowie website and one
> version available would not do "rollouts". What are the advantages of
> doing these?
> Please explain and I thank you in advance for your explanation.
> Mark Ferrante
> Shrine of THE SHEIK

Gregg Cattanach

Dec 17, 1999, 3:00:00 AM12/17/99

I'm not sure if Eugene was very clear, so let me try. 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

ICQ #2266410

"EUGENE COOPER" <> wrote in message

Martins Sanders

Dec 17, 1999, 3:00:00 AM12/17/99
On Fri, 17 Dec 1999 08:03:32 -0500, "Gregg Cattanach"
<> wrote:

>One of the biggest features of the new Snowie 3.0, is that all

are you sure about it? ( that ALL ROLLOUTS)

> rollouts and
>evaluations are played with a live cube, unlike Snowie 2.0 (which had that
>option, but only on specific settings).


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