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Subject: Re: Speaking of the Thesis by Marcel van Kervinck (hopefully no storms)...

Author: Uri Blass

Date: 14:45:15 09/06/02

Go up one level in this thread


On September 06, 2002 at 15:46:53, Tony Werten wrote:

>On September 06, 2002 at 14:45:11, Dann Corbit wrote:
>
>>Did anyone notice his cutoff idea in the evaluation function?
>>
>>It seems to me to be a very good idea, and I don't know if others have tried it
>>out.
>>
>>Basically, it consists of three modes with two early exits...
>>
>>1. If the material + structure score alone is dominant enough, it exits right
>>away.
>>2. Otherwise, it processes the piece list.  If that score is dominant, it exits.
>>3. Otherwise, it does a full board control scan for all 64 squares.
>>
>>It is described starting on page 62 under the section "3.3.2 Multi Staged
>>Design"
>>He gets roughly 71% evals returning in stage #1, 13% in stage #2 and 7% in stage
>>#3.
>>
>>It seems like it might be a big win to do it that way.
>
>It's called lazy eval and is not a good idea. The times it is wrong happen to be
>the important ones.
>
>Tony

I use incremental evaluation.
The only cases when I can be wrong in being lazy is in my qsearch because I do
not make every stupid capture in my qsearch.

Example:
Suppose I search the position after
1.e4 e6 2.Bb5 a6 as the root position and have a score of 0.0 pawns at depth 2.

If I search 3.c4 axb5 and goto qsearch then I do not make the move 4.cxb5
inspite of the fact that with possible high positional scores I cannot be sure
that the positional score after 4.cxb5 is not high enough to justify that move.

Uri



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