Re: [computer-go] Designing faster, better influence functions

[Peter Drake <drake@xxxxxxxxxx>]

This is something that has always confused me:  I can see how to 
incrementally update the liberty count of a block if it is simply 
expanded by one stone, but what if two blocks are merged or (in an 
undo) split?  Blocks of vacant points can be split by a move or merged 
by an undo.

Similarly, it is difficult for a block to keep track of neighboring 
blocks if they are splitting and merging all over the place.  Do people 
have a way of doing this, or do you just recompute this information 
from scratch after each move?

Peter Drake
Assistant Professor of Computer Science
Lewis & Clark College
http://www.lclark.edu/~drake/


On Monday, November 1, 2004, at 07:29  PM, David Fotland wrote:

> Many Faces also keeps incremental lists of liberties and liberty 
> counts,
> block sizes, etc.
> It's very fast.
>
> David
>
> > -----Original Message-----
> > From: computer-go-bounces@xxxxxxxxxxxxxxxxx
> > [mailto:computer-go-bounces@xxxxxxxxxxxxxxxxx] On Behalf Of Evan Daniel
> > Sent: Monday, November 01, 2004 5:33 PM
> > To: computer-go
> > Subject: Re: [computer-go] Designing faster, better influence
> > functions
> >
> >
> > On Tue, 2 Nov 2004 02:14:52 +0100, Mark Boon <tesuji@xxxxxxxxxxxxxxxxx> wrote:
> > > I don't think I would want to get into using CPU-specific
> > > instructions. But I must say I've sometimes thought about
> > what could
> > > be useful to have in terms of Go-specific hardware. In
> > Tsume-Goliath I
> > > think I found that the single most expensive function was
> > getNlib(),
> > > which would retrieve the number of liberties of a chain at
> > a certain
> > > coordinate and put the coordinates of those liberties in a little
> > > list, with a maximum of 'n' liberties. A very simple and basic
> > > function, used in a lot of different places. The total time
> > spent in
> > > this one function was something like 20 or 30%.
> > Have you looked at how GNU Go deals with the problem?  The
> > GNU Go board code keeps incremental updates of things like
> > liberty counts, liberty locations, etc.  I don't really
> > remember how fast it is, but I don't think it spends that
> > much of the runtime on it.
> >
> > Evan Daniel
> > _______________________________________________
> > computer-go mailing list
> > computer-go@xxxxxxxxxxxxxxxxx
> > http://www.computer-go.org/mailman/listinfo/computer-go/
>
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