RE: computer-go: Ratings, God and everything.

["jliu" <jliu@xxxxxxxxxx>]

// I think there is a language problem , so I rewrite it in C.
God[0].ranking = 9;   // 9p player
God[0].lookdepth = m; // whatever a 9p's lookdepth is. est. 30.
for(i=1;i<=200;i++) {
  God[i].lookdepth=God[i-1].lookdepth+1;
  God[i].ranking = God[i-1].ranking + 3;  // assume 3 for a diff. of 1
}
printf("The ranking of a god who can see to the end is:"+God[200].ranking);

result: 609p.

You may wish to adjust some parameters but I believe the algorithm is
correct.  To me, look 1-level deeper is 3 stones.

James ( Jun Liu )

-----Original Message-----
From: owner-computer-go@xxxxxxxxxxxxxxxxx
[mailto:owner-computer-go@xxxxxxxxxxxxxxxxx]On Behalf Of Nick Wedd
Sent: Wednesday, September 27, 2000 5:16 PM
To: computer-go@xxxxxxxxxxxxxxxxx
Subject: Re: computer-go: Ratings, God and everything.


jliu <jliu@xxxxxxxxxxxxxxxxx> writes
>I think the Go rating is not additive.  I mean A can give B 3 stone (to
>reach 50/50 chance), B can give C 2 stone does not add-up to A can give C 5
>stone.  In fact I think 2+3<5.  Maybe God can only take 4 stones from 9p
>pros, but that should not be translated into God has a ranking of 13p.

Of course.  The handicap-giver moves first, so an n-stone handicap is
worth n-1/2.

In your example, 1.5 + 2.5 < 4.5, which I do not doubt.

Also you assume that a difference of 1 in p ratings is worth one stone.
This is only true for amateur ratings.  For p ratings, it is more like
1/3 stone.

>I think when closer to God (I mean perfect play), the non-linearity is very
>strong.  Let's say people can see one-step further is 3 stones stronger,
>God's (again, I mean perfect player) ranking is 3 times number of more
steps
>God can see as compared to 9p pro.  A Go game has about 230 moves.  So,
>God's ranking is 3 x (230-30?) = 600p.
>
>Anybody has serious objection to this (stepwise) estimate?

I think it is seriously wrong.  God is around 12d, or 18p.

If he were 600p, = 206d, he would be able to give me a 205 stone
handicap.  I guarantee that I could win with only 180 handicap stones,
even while drunk.

Nick
--
Nick Wedd    nick@xxxxxxxxxxxxxxxxx