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## [Bug-gnubg] Re: rollout settings

 From: Gordon Bower Subject: [Bug-gnubg] Re: rollout settings Date: Tue, 29 Oct 2002 11:02:23 -0900 (AKST)

```>
> Rotate Rolls. The first 1296 rolls are preset to give a combination of =
> all possible sequences of rolls for player X and O on the upcoming two =
> rolls. In fact, looking at the change log I see:
>
> 1 679 616 is 36^4, so it looks like rotation is in place for the first =
> two rolls for each player.
>
> There has been some discussion about what happens if you do a rollout of =
> < 1296 trials with rotation enabled. If the rolls are not random, you =
> might skew the results if you do less than 1296 trials because, for =
> example, you miss all sequences where X rolls 66.

At risk of asking something obvious....

Why do we do rollouts in multiples of 36/1296?

Can't we gain a huge savings in how long deep-ply rollouts take, if we do
them by powers of 21, and weight each result in proportion to
2^(non-doublets rolled in this dice sequence?) It's only a tiny increase
in the complexity of the mean and variance calculations, in exchange for
making each ply take only 1/3 as many rolls.

GRB

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