Re: [Bug-gnubg] Crawford Cubeful equity not matching cubeless during rollouts.

[Joern Thyssen]

On Thu, May 06, 2004 at 12:50:50PM +0200, Jim Segrave wrote
> On Wed 05 May 2004 (15:08 -0400), Eberlein, Robert (REBERLEI) wrote:
> > I have noticed bizarre results during rollouts of the Crawford game for
> > matches.  The cubeless and cubeful equities should always match, since
> > the cube cannot be turned.
> > 
> > They seem to start out that way, but as the rollout proceeds each
> > alternative getting rolled out on my Windows 2000 machine eventually
> > shows a significant discrepancy between the cubeless and the cubeful
> > equities.  I think the cubeful equities are messed up.  The simplest way
> > to reproduce the problem is to start a 3 point match, resign a gammon on
> > move 1 of game 1, and then analyze a 43 opener in game 2.  My rollouts
> > were 0-ply (expert level) untruncated, with variance reduction.  I used
> > gnubg 0.14.2 - dev 1.1578 040503.
> 
> Is it true that the cubeful and cubeless should be the same? The value
> of a gammon to the trailer is very much a function of how much they
> are trailing by. For example, if you are 3-away 1-away Crawford and
> win, the next game 2-away 1-away is going to be played for DMP in a
> cubeful environment, so in fact winning the Crawford game makes you
> 50% to win the match. That's not so in a cubeless match

"cubeless" just means that the /current/ game is played without cube...
which make it rather meaningless number. 

So the equities should in fact be identical.

Joern