RE: computer-go: Go4++: Passing in tsume searches.

["Tim Hunt" <timhunt@xxxxxxxxxxxxxxxxxxxxxxx>]

> > It works if you change the shape a bit, e.g.
> >
> >  9 . . * * * * * . .
> >  8 . * * 0 0 0 * * .
> >  7 . * 0 0 . 0 0 * .
> >  6 . * 0 0 * * 0 * .
> >  5 . * 0 . * * 0 * .
> >  4 . * 0 0 0 . 0 * .
> >  3 . * 0 0 0 0 0 * .
> >  2 . * * * * * * * .
> >  1 . . . . . . . . .
> >    A B C D E F G H
> >
> > Then * cannot almost-fill the area with a nakade shape.
> >
> > Martin
> >
>
> So that's two examples found for having to pass twice...
> anyone construct a 3-pass situation?

> >  9 . . * * * * * . . .
> >  8 . * * 0 0 0 * * . .
> >  7 . * 0 0 . 0 0 0 * .
> >  6 . * 0 0 * * . 0 * .
> >  5 . * 0 . * * . 0 * .
> >  4 . * 0 0 0 . 0 0 * .
> >  3 . * 0 0 0 0 0 * . .
> >  2 . * * * * * * * . .
> >  1 . . . . . . . . . .
> >    A B C D E F G H

Surely this works.

> I'm praying that I can have some sort of limit on the
> number of passes allowed because some of my tsumego
> searches are getting 80 ply deep and half the defensive
> moves are passes!! Passes are very expensive in tsumego
> searches firstly because they add an extra move to
> look at within any given ply and they also fail to fill
> up space in the search region and so leave more choices
> in the next ply.
>
> Am I the only one who's searches are clogged up with
> passes? How have other people dealt with this?

Well, "A, pass, B, pass" and "B, pass, A, pass" are basically the same line
of play. Removing that redundancy should halve of quater the search time.

Tim.