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Subject: Re: What information to store in book learning?

Author: José Carlos

Date: 13:27:23 01/02/01

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On January 02, 2001 at 16:10:53, Christian Söderström wrote:

>On January 02, 2001 at 15:36:45, Jon Dart wrote:
>
>>On January 02, 2001 at 05:30:07, Christian Söderström wrote:
>>
>>>So I am left with 4 bytes. I want to use these to store statistics
>>>about the move, to support a future book-learning function. But the
>>>thing is I'm not sure what information would be most useful to store!
>>>
>>>I have a couple of ideas obviously but I am very interested to hear
>>>any ideas others might have. 4 bytes is pretty much, but not enough
>>>to get too crazy :)
>>>
>>
>>Arasan implements book learning by keeping a float value (which you
>>can store in 4 bytes) for each position. If it gets a big + score a
>>few moves out of book, it goes back and ups the float value for
>>the last book move and (in decreasing amounts) the preceding book
>>moves. Similarly it decreases the scores if the score a few moves
>>out of book is bad.
>>
>>Crafty does something similar. The idea is that in subsequent
>>games you favor moves with positive learned values and avoid moves with
>>negative learned values.
>>
>>This is certainly not foolproof and not very sophisticated but it's
>>at least a basic form of learning.
>
>Something like that definately works. Isn't a float a bit
>overkill though? (No pun intentended)
>
>Anyway I always figured one of the big points of adding
>learning was that the program would avoid playing openings
>which it plays poorly long-term, not just those that result
>in bad positions a few moves out of book. For instance,
>Mint often plays the french with black now, and does very
>poorly (especially against humans), however it doesn't
>understand that it's doing badly (and in fact it might
>objectively be fine) until it sees a material-winning
>or mating attack 30 moves in the game.
>
>So isn't it possible to supplement your idea by also
>learning from the end-result of a game?

  Of course many kind of sophisticated learning technics are possible, but in
such cases (like the french you talk about) I see it easier to build a book
where the french is forbidden for the program.
  Right now, I'm working on Averno's book that way, and results are becoming
better.

  José C.

>- Christian
>
>>--Jon



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