Re: [gnugo-devel] A speedup

[Arend Bayer]

Portela wrote:

> A simple idea : when defending, first look for easy ways to gain enough
> liberties.
(...)
> Performance :
>
> * reading nodes : -12%
> * owl nodes : not worth mentioning (but improved)

I wanted to try this, too! I think we should look for exact timing results,
however. You are duplicating a lot of work of the move generation. (And
note that many of the reading nodes you have saved will be extremely
short ones, where the attacking code would return immediately.)

A compromise might be to add shortcuts e.g. in defend4 as soon as we
discover a move that gains 5 liberties.

> * I'm not 100% sure, but I haven't been able to think of a position where
>   a ko could mess up the result. So I ignored them, but maybe someone should
>   take a (better) look.
No, that is no problem. As said above, the attacking code will
immediately give up once the move your fast_defense would suggest is
played.

Arend