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Subject: Re: Evaluation Approach

Author: William H Rogers

Date: 14:49:06 01/15/99

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On January 14, 1999 at 17:49:15, KarinsDad wrote:

>I have been considering the possibility of having two sets of evaluation
>routines in my code. One set is a quick simplistic evalution and the other is a
>slower, more detailed evaluation.
>
>The simplistic evaluation consists of any set of data which can quickly be
>calculated such as material and safe squares. I was also going to have my pawn
>structure score here as well since I am using one large hash table for it,
>hence, since pawn structures are relatively stable and once calculated, they can
>be re-used for multiple positions across the search tree.
>
>The detailed evaluation was going to consist of the simplistic evaluation, plus
>modified piece values (based on where they are and what they are doing), square
>control, king safety, etc.
>
>My questions are:
>
>1) Has anyone used an approach similar to this, and if so, is it successful? and
>2) If I use this approach, where should I use each evaluation? I was thinking of
>using the detailed evaluation only on the first few ply (maybe up to 4), on the
>entire PV, and at the leaf nodes of non-quiescent paths (once they became
>relatively quiescent again). I would then use the simplistic evaluation
>everywhere else for speed. Does this seem reasonable, or am I missing something
>here? Will having scores derived from two different evaluations result in a
>skewing of the search?
>
>Thanks,
>
>KarinsDad

Consider the following, but I am not sure it would suite your needs

1. first part of eval
2. if ply < 2 then next ply
3. the rest, or the best eval
4. next ply.

One routine with a banch in it. Of course you could set your own branching
factor.
I tried someting like this at the final ply to try to look beyound the horizon.
Bill



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