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Subject: Re: Live chat with Feng-Hsiung Hsu (of Deep Blue fame) on ICC

Author: Vincent Diepeveen

Date: 08:15:14 10/11/02

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On October 11, 2002 at 11:11:01, Jeremiah Penery wrote:

>On October 11, 2002 at 10:46:16, Gian-Carlo Pascutto wrote:
>
>>On October 11, 2002 at 10:38:12, Jeremiah Penery wrote:
>>
>>>On October 11, 2002 at 08:09:59, Vincent Diepeveen wrote:
>>>
>>>>you skip one important point. Because of a simplistic evaluation
>>>>it was able to get 12.2 ply. If you use a more complex evaluation
>>>>then you do fullwidth not get 12.2 ply at all, but more like 10.5 ply.
>>>
>>>It did evaluation in hardware.  The complexity of the function has NOTHING to do
>>>with the speed of computing it.  This is obviously something you don't
>>>understand, or you wouldn't be writing crap like the above, or the below.
>>
>>You missed Vincents point. His point was that a more complicated
>>evaluation (with bigger positional scores) will slow down the search
>>compared to (for example) a piece-square evaluation, because it causes
>>more instability.
>
>Having a more complicated evaluation does not require having bigger positional
>scores, but I agree that in the general case that is what happens.  However,
>search instability depends on the correctness of your evaluation function and
>your move ordering - the variability of the evaluation function is secondary.
>If your evaluation is very complex, but also extremely accurate, it will be far
>more stable than a simpler but less accurate evaluation will yield.

If you always return 0 as score, then any move will give a cutoff.

If you are material based, just material, then capturing a piece will
give usually a cutoff.

If you have a complex evaluation, then you do not know in advance whether
trying a capture is going to give a cutoff. Obviously it's harder to order
moves too. If you knew ahead which move would going to give a cutoff for you,
why the hell would you do a search anyway?

It's a trivial thing in algorithms. Already reported years ago by
the darkthought team (Peter Gillgasch).

Best regards,
Vincent



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