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Subject: Re: Beating MTD(n,f)

Author: Dann Corbit

Date: 13:04:49 06/07/01

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On June 07, 2001 at 06:52:07, Tony Werten wrote:
>On June 06, 2001 at 10:32:14, Gian-Carlo Pascutto wrote:
>>On June 06, 2001 at 09:06:40, Vincent Diepeveen wrote:
>>>Noop it doesn't make it void.
>>>To get from 100 to 200 is harder as it is to get from 10 to 20.
>>If they mean the same thing, not at all.
>>Note that I said you should be taking convergence acceletrators
>>into account. Every competetive implementation of MTD(n,f) has
>>them and the papers suggest them so that is a valid requirement.
>>
>>If you increase the window forecefull from 100 to 200 when you
>>are using millipawns it's the exact same thing as increasing it
>>from 10 to 20 when you are using centipawns.
>>
>>If you rely purely on the fail-soft and do not adjust the bounds
>>with the accelerators, I think you are right, but I really would
>>like to see evidence of it. When forcing the bounds it's just the
>>same thing however, and that is what every good MTD(n,f) implementation
>>is doing.
>>
>>You are basically saying that the difference between 0.1 and 0.2
>>is different from that between 0.1 and 0.2. No it's not :)
>
>I think what Vincent is saying is that there's a difference between 0.1 and 0.2
>and 0.10 and 0.20 The first 2 are following each other while the second 2 have 9
>numbers between them.
>
>Suppose the current score is 0.10 Now I find a move with score 0.12 MTD will
>fail and I have to research. If I had scored 0.1 then the new move would have
>also been 0.1 and MTD wouldn't have to research.
>
>Of course is this not only true for MTD, but for all minimum window searches,
>but in MTD the first (best) move is also done with mws and this is most of the
>time the one that has the fluctuating scores.

I imagine that this is a stupid question, but what happens if we simply truncate
on the test to research?  We could just reorder the moves at that point instead,
if the difference is tiny.



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