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Subject: Re: Crafty 18.13 and Deep Blue extension limit removed

Author: David Rasmussen

Date: 07:17:38 01/13/02

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On January 12, 2002 at 20:37:36, Robert Hyatt wrote:

>On January 12, 2002 at 10:07:11, Pham Minh Tri wrote:
>
>>main.c: "Deep Blue extension limit removed and restored to one ply of extension
>>per ply of search."
>>
>>Amazing! I still think that Crafty 18.12 is significantly stronger than previous
>>versions because of that limit.
>
>
>I did a lot of testing and found that in real games, the DB method simply
>does too many extensions for my liking.  The normal Crafty search can explode
>in some positions.  It happened more often with the DB limit (no more than
>two plies of extension for any two consecutive plies, rather than the current
>one ply of extension max for any ply.)

How about a general limit saying if we're at ply 7, and we have extended 4.25 so
far, it is ok at this ply to extend as much as 2.75, since this will amount to 1
per ply on average anyway. I realize that this would yield even more extensions
than with the deep blue method, but if it could be restrained correctly, I think
it would also be tactically stronger. I will try it for sure.

/David



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