Re: [Bug-gnubg] Bug - Multiple errors in rollouts.

[Joern Thyssen]

On Wed, Oct 15, 2003 at 08:24:15PM -0400, Eberlein, Robert (REBERLEI) wrote
> I rolled out the same position using three Windows versions of gnubg:
> 0.14-dev 1.1379, 0.14-dev 1.1399, and 0.14-dev 1.1427.  To my dismay, as the
> version number of gnubg increased, the displayed results were progressively
> worse!  I have attached the rollouts as files: Rollout_1_1379.sgf,
> Rollout_1_1399.sgf and Rollout_1_1427.sgf
> 
[snip]
> Because the best way to win is to close out two checkers, gnubg must break
> the prime to execute a trap play, if the two checkers make an anchor.
> Therefore, I expected gnubg to lose some gammons and backgammons if user
> gets lucky, and version 1.1379 seemed to give reasonable results.  Bug #1 -
> Both of the later versions show zero for the lost gammons and lost
> backgammons.  In addition, the standard error displayed for both lost
> gammons and lost backgammons is insanely large and increases as the rollout
> proceeds.  

I've committed a fix. 

> Bug #2 - Version 1.1427 (I think the problem happened by October
> 4, 2003) 

I'm guessing September 22. I fixed a similar problem for cube rollouts,
but broke chequerplay rollouts. Now I've completely removed the
offending code :-)

> shows user losing small numbers of gammons and backgammons, after
> he has borne 13 checkers off!

I can't reproduce that. Perhaps my fix for bug#1 fixed this one too. Can
you check with the next build, please?

Jørn

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