Re: [gnugo-devel] New joseki patterns

[Evan Berggren Daniel]

On Sun, 3 Nov 2002 address@hidden wrote:

>
> > # Joseki side extensions, and shape fixing
> >
> > #added 3.3.12 evand
> > Pattern J44
> >
> > ?O....??
> > XO.*..??
> > xXO...??
> > xx....??
> > --------
> >
> > :8,j
> >
> > ?O....a?
> > eO.*..b?
> > cfO...??
> > d.....??
> > --------
> >
> > ; (!omoyo(a) || !omoyo(b) || x_somewhere(c,d))
> > ; && !weak(e) && !oplay_attack_either(c,e,f)
>
> I believe some j pattern like this may be appropriate.
> See also nngs4:30.

Looks like it would help there.

The new version fixes this case.  However, I don't think making it a full
J pattern is a great solution, but making it just a j pattern isn't
sufficient.

>
> But !oplay_attack_either(c,e,f) looks wrong. I'm not
> sure if this will cause a crash if there's a B stone
> at c, but in any case it seems to me that both this
> and x_somewhere(c,d) should be just !attack(f).

Sounds good.

>
> Also, the omoyo(a) and omoyo(b) are presumably intended
> to prevent overconcentration. However this pattern
> would still be OK if there are O stones at a or b.
> True a small amount of overconcentration results but
> even so the shape the shape needs to be fixed.

They're to prevent concentration, and also there under the theory that if
that region is O's moyo, then the fight after the cut is to O's advantage,
and so there may be more urgent plays in the region.  There should
probably be a second pattern with a lower value and no moyo restriction as
the proper way to address this.

Also, the other pattern (J45) causes a PASS at trevord:290 (the only
change to regressions).  The engine
now plays R10.  I think
this is an improvement over Q8, but maybe not the best play.  Perhaps
there should be another test added?

So here's the new version.  I have not yet checked regressions on it.


Thanks

Evan Daniel

Index: patterns/fuseki.db
===================================================================
RCS file: /cvsroot/gnugo/gnugo/patterns/fuseki.db,v
retrieving revision 1.19
diff -u -r1.19 fuseki.db
--- patterns/fuseki.db  8 Oct 2002 20:06:39 -0000       1.19
+++ patterns/fuseki.db  4 Nov 2002 05:05:57 -0000
@@ -2447,4 +2447,36 @@
 > replace(d,*)


+# Joseki side extensions, and shape fixing
+
+#added 3.3.12 evand
+Pattern J44
+
+?O....??
+XO.*..??
+xXO...??
+xx....??
+--------
+
+:8,J
+
+?O...ab?
+XO.*..??
+xcO...??
+xx....??
+--------
+
+; (!omoyo(a) || !omoyo(b)) && !attack(c)
+
+Pattern J45
+
+???.....???
+??o......??
+?oO........
+oO.....*...
+...........
+...........
+-----------
+
+:8,J
 # END OF FILE