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Subject: Re: Couple of chess programming questions

Author: Dann Corbit

Date: 10:33:01 09/11/02

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On September 11, 2002 at 05:19:27, Andrew Williams wrote:

>On September 10, 2002 at 20:17:21, Gian-Carlo Pascutto wrote:
>
>>On September 10, 2002 at 19:52:32, Dann Corbit wrote:
>>
>>>If MTD(f) were linear [or linear behavior happened more than once in a blue
>>>moon], then PostModernist would not score nearly so well, I think.
>>
>>I'm fairly sure Andrew uses convergence accelerators, so it's not
>>strictly MTD(n,f) in PostModernist.
>>
>
>Yes. I do 1, 1, 2, 3, 4, 5, 6, 7, 7, 7... I've tried all sorts in my time:
>
> 1,  2,  4,  9, 16, 25, 36, 36, 36...
> 1,  1,  2,  3,  5,  8, 13, 21, 34, 55, 55, 55...
> 1,  2,  3,  4,  4,  4...
>
>If I get FH, FH, FH, FH, FL, I start heading back down subtracting from the
>first numbner.
>
>All of these work better for me than just using 1 for every step.

Have you tried a "tiny" NegaC* centered on f?  I would be interested to see how
a binary search with a very small window fares.  The reason I mention it is that
I suspect your implementation of MTD(f) framework is as good or better than
anyone else's.  The rest of us just play with toys.

For instance, a 256 unit wide interval will take 8 searches.  If you know the
average value for the number of searches applied, you could try a window one or
two bits narrower and see how it comes out.

Just a thought.



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