Re: [gnugo-devel] eye patterns

[Gunnar Farneback]

Paul wrote:
> this patch is extracted from paul_3_18.7. regression delta is negative,
> but i believe the patch itself is correct.
> 
> strategy2:77    FAIL H15 [H3]
> strategy2:80    FAIL S8 [P4|Q4|Q3]
> nngs3:740       FAIL F2 [!F2]
> 
> 
> strategy2:77 now gnu go prefers H15 since it thinks H15 attacks H17. the patch
>              saves some owl nodes here: original gnu go with OWL_NODE_LIMIT
>              set to 1200 says H15 as well.

This test is revised by one of Evan's pending patches and should no
longer be a problem.

> strategy2:80 S8 looks like a correct move to me (in addition to P4, Q4 and 
> Q3).
>              it's not that solid, but it does win the semeai. i don't exactly
>              understand why it doesn't like Q4 anymore, owl_does_attack Q4 R5
>              says "1". however, nonpatched gnu go with OWL_NODE_LIMIT raised
>              to 2000 agrees with patched one that S8 is better than Q4.

S8 leaves significant aji and loses points compared to the connecting
moves so I wouldn't consider it as correct. But the choice of moves is
a move valuation issue and unrelated to this patch.

> nngs3:740    gnu go was never good in reading such unclear positions. with
>              the patch it sees that E2 doesn't owl defend C2 (because it
>              orders attacking moves differently and doesn't run out of nodes).
>              so it devalues E2 a couple points and F2 becomes the top move.
>              nonpatched gnu go with OWL_NODE_LIMIT == 2000 doesn't count E2
>              as an owl defence for C2 (it doesn't like F2 at all, but that's
>              another story).

Seems to be passing rather much by luck currently.

Most of the pattern changes look correct. A few comments though:

> @@ -661,19 +660,13 @@ Pattern 469
>  
>  Pattern 491
>  
> - .
> -!X!
> -
> -:0001
> -
> -Pattern 492
> -

Anything wrong with that pattern?

> @@ -2783,13 +2776,14 @@ x..x@
>  Pattern 6261
>  # tm New Pattern (3.1.22) (see owl:111)
>  
> -  @
> -!.*.!
> +  )
> address@hidden>.@
>  
>  :0011

I don't quite get this one.
 
 
>  Pattern 6262
> +# FIXME: I don't understand this pattern. Is it correct? -pp
>  
>    !
>  !x..!

Agreed, looks strange.

> @@ -4399,6 +4393,8 @@ Pattern 70004
>  
>  
>  Pattern 70005
> +# FIXME: This pattern looks like 1112 to me. "$...<." seems to be
> +#     attackable at '<'. -pp
>  
>  $.....@

Also agreed. The "$>..*." pattern should be added too.

/Gunnar