Re: [Bug-gnubg] Bug in gammon price calculations using inverted asymmetric MET's

[Philippe Michel]

On Sun, 24 Mar 2013, Maik Stiebler wrote:

> Hi folks,
>
> I tried to do some analysis using the Jacobs-Trice 100 MET and got a 
> surprising result.
>
> Upon investigation, I found that in non-variance-reduced, non-truncated 
> rollouts, the rollout match equity given by gnubg did not match my hand 
> calculation based on the cube statistics info. I suspect that on inversion of 
> the match equity table, the gammon values don't get inversed. This seems to 
> influence not only rollouts, but also evals. I will refrain from an awkward 
> description of my debugging process until you tell me this is not a known bug 
> and just give you a symptomatic example (sorry for the German, I hope it's 
> easy enough to follow):

I don't think this is a known bug. I reproduced your case with 0-ply 
evaluations (where looking at what happens step by step should be easier) 
and the results from the two positions differ as well.

I took a quick look at the code and didn't find anything obvious, except 
that the problem is unlikely to be in the inverting but rather in the 
handling of asymetric METs in general.

You don't write it explicitly but does the first result, with the table 
not inverted, match your hand calculation or do they both seem wrong ? I 
would expect the latter.