Re: [gnugo-devel] two stone games

[Arend Bayer]

Stéphane wrote:

> I wonder if we could use an alphabeta-like idea to speed up that code.
> The idea is that, fondamentaly, it works by reducing the opponent's
> territory step by step, so this is the first place in gnugo where we
> explore a reading reading while having have a clear valuation (or
> should we call it a pay-off?) along the paths.
>
> So it would be really nice and faster if we could prune some variations
> with alphabeta ideas, like : "ah, I have already proven that I can
> reduce that territory by 10 points in that old variation, but now
> my opponent claims it can prevent me from getting more than 4 here,
> so I can cut some work here"

This sounds good but does not fit to how the code currently works. At
the moment, the recursive breakin reading can only decide _whether_ there
is a break-in possible, not how deep it will be. To decide how deep, the
recursive code is, in case of success, called again with a shrunk goal
area.

Your idea seems worthwile, not so much for performance but for precision
to avoid the crude heuristic mentioned in the previous sentence. Most of
the time the break-in code seems to be investigating unsuccessful
break-in attempts, and there alpha-beta reading wouldn't make a
difference.

Arend