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

Author: Robert Hyatt

Date: 09:21:23 10/11/02

Go up one level in this thread


On October 11, 2002 at 11:32:11, Jeremiah Penery wrote:

>On October 11, 2002 at 11:15:14, Vincent Diepeveen wrote:
>
>>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.
>
>I wouldn't call that an evaluation function.
>
>>If you are material based, just material, then capturing a piece will
>>give usually a cutoff.
>
>For the overly simple case(s) (only material or similar), you're correct.  I was
>using 'simple' evaluation to mean something like piece/square tables plus a few
>basic positional things.  Material only is uninteresting.
>
>>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?
>
>Why is it harder to order moves when you have a more complex evaluation?  It
>would seem to depend more on the accuracy of the evaluation, rather than the
>complexity.


You are missing the point.  What is hard/impossible for vincent is impossible
for
anybody else to do.

end of story.

Once you realize that, these threads will get a lot shorter...



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