[computer-go] Noise reduction in alpha-beta search

[Chrilly]

It can't be. He was probably studying the general game, not Go

Ingo Althoefer published his results in the context of chess. Alpha-Beta Search was until recently not a topic in Go (besides its not possible).

The score in Go is additive, if the score is territory.

But that is not a possible evaluation function. E.g. in the first stages only on small parts of the board is white/black territory defined. The rest is influence/Moyo (or nothing). One needs also some notion of weakness of a group. The All or Nothing (Group is Living or Death) approach does not work. There must be some evaluations/stages in between. If a weak group controls some territory, this territory should also count less...

This problem is to be solved by deeper search.
Yes. But it is very difficult to find reasonable "quiet" criterions. One has to stop the search at one point, because otherwise it explodes. 

Chrilly
  ----- Original Message ----- 
  From: compgo123 at aol.com 
  To: computer-go at computer-go.org 
  Sent: Tuesday, April 10, 2007 5:23 PM
  Subject: Re: [computer-go] Noise reduction in alpha-beta search


  It can't be. He was probably studying the general game, not Go. The score in Go is additive, if the score is territory. 2-steps approach make some sense, but not in general situation. At each step the pendlum swings to one side is the nature of the game. Nothing wrong with it. One gets the same problem with single step evaluation too. This problem is to be solved by deeper search.

  Daniel Liu

   
  -----Original Message-----
  From: c.donninger at wavenet.at
  To: computer-go at computer-go.org
  Sent: Tue, 10 Apr 2007 1:46 AM
  Subject: Re: [computer-go] Noise reduction in alpha-beta search


  Ingo Althoeffer has published some time ago a theoretical article about this idea. He called it "telescope" evaluation. According his theorectical findings is the error propagation not better than the usual approach.

  Chrilly

    ----- Original Message ----- 
    From: compgo123 at aol.com 
    To: computer-go at computer-go.org 
    Sent: Monday, April 09, 2007 4:48 PM
    Subject: [computer-go] Noise reduction in alpha-beta search


    I think following is a way to reduce the noise in alpha-beta search. Instead of using the evaluation values, use the cummulative evaluation values. That is the sum of the evaluation values of each node of the playing path under examination.


    Daniel Liu

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