On Nov 13, 2007 11:14 AM, Massimiliano Maini <address@hidden
1- When you say "cubeless", do you mean
that the game will be truncated
right after the very first double decision, if any?
I understand your
example of a double/pass, but what about a double/take
A cubeful rollout trial will be truncated whenever GNUbg thinks it's a (re)double/pass. The reason is simply this: the cubeful equity is known at that point: +1 in EMG. Also, in a real game, play would be over when one side passes: GNUbg works the same way. For the w/g/bg breakdown and cubeless equity figure, the values from the cube evaluation at that point are used.
When a (re)double/take happens, the trial just continues, since the cubeful equity isn't known at that point. The new cube value and position will be taken into account ("fully live cube").
2- At the end of the trials, the computed "cubeless"
lead to a "cubeless" equity that will be
translated into a cubefull
equity via the janowski formula, right?
No. GNUbg currently has no such feature. Either it's a cubeless rollout and only gives you a cubeless equity, or it's a cubeful rollout and uses a live cube to determine cubeful equity (not a Janowski approximation).
It might be a nice feature though, to have GNUbg give us a Janowski cubeful equity in cubeless rollouts, handy for those positions where GNUbg's cube actions in a rollout lead to many (quick) incorrect double/passes (with the associated wrong w/g/bg breakdowns...). I think Jellyfish uses this approach, and Snowie also has it as a feature ("cubeful" equity in a cubeless,
i.e. no live cube rollout).
example, the W/G/BG%
are the "cubeless" results of the rollout,
the CL is the "cubeless"
equity and CF is comuted via Janowski formula?
3- Any idea why a simple "full cubefull rollout"
approach is not implemented ?
> > Rollout details:
> > Centered 1-cube:
> > 0.669 0.146 0.002 - 0.331 0.078 0.003 CL +0.405
> > Player player owns 2-cube:
> > 0.670 0.152 0.001 - 0.330 0.077 0.003 CL +0.854
I mean letting gnubg play against himeself cubefull
and record the outcome.
So, this is what a GNUbg cubeful rollout does.
I suspect this comes from the fact that its result
would not be a W/G/BG%
but more an equity (for money) or a MWC (for match),
but hey, these
are what matters ...
The w/g/bg are still basically the same (as they would be in a cubeless ("dead cube") rollout), except that any (re)double/passes during the rollout will use the evaluation breakdown at that point (
i.e. truncated). The "live cube" is reflected in the cubeful equity.
Another reason is that the current method, truncating
at double decisions,
should/could "reduce the variance" (provided
the evaluation is good).
So the truncating only happens when it's a (re)double/pass. This reduces variance and speeds up the rollout.