Re: Benson Rules!

["P.J.Leonard" <P.J.Leonard@xxxxxxxxxx>]

Martin Mueller wrote:

[snip]
> Benson's algorithm finds blocks that are safe even if the opponents gets an
> unlimited number of moves in a row. In my Ph.D. thesis and in the GPW'97
> article, I have studied some extensions which are less elegant
> mathematically, but more useful under the usual alternating play. I needed
> them for my endgame solver, which first computes safe stones and
> territories and then analyzes the connected components of the rest of the
> board. I believe my extensions are also proven and true. (There is one bug
> in the dame-finding algorithm as printed in the thesis but this has nothing
> to do with the earlier safety calculation.)


 I studied your thesis and even started to implement some code
when I was implementing the scoring for pubgo (many thanks for
making your work public).

I found that to implement the scheme for a general case
(many strings and false eyes etc) would have required a considerable
effort (in terms of program structure). The problem is deciding which
strings are the focus of the algolrithm. It looked like you would
need to try all combinations or have some heuristics for flaging
a stable core. I am missing something ?


 I also came to the conclusion that us humans do not think like this.
In the end I just used a brute force search to detect life / death. 

 Has anyone compared Bensons/Martins scheme with brute force ?

 cheers Paul.