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Subject: Re: Search algorithms and effeciency

Author: Rudolf Huber

Date: 09:47:34 05/31/01

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On May 31, 2001 at 12:26:19, Vincent Diepeveen wrote:

>On May 31, 2001 at 08:11:16, Dan Andersson wrote:
>
>>You are comaring apples with oranges, re-search in MTD is never full width. Thus
>>even a thusand re-searches (clearly an extreme case) may be less expensive than
>>one full width re-search (not bloody likely, but still possible). You never seem
>>to get that point.
>
>Please annotate in each research how many NEW nodes you searched
>and how many of those you had to evaluate. That would be cool
>info.
>
>It's too expensive for my poor evaluation. Even though i store
>evaluation both in transposition table AND special eval table,
>note i do 8 probes which is pretty something compared to most
>which do 2 probes or so.
>
>But if i do researches i search loads of new nodes and loads of new
>evaluations are needed.
>
>Please post here how many NEW nodes you search!
>
>If you measure that you will get scared to death!
>
>Also search fluctuations of 0.3 pawn are very normal first
>few plies in diep. Of course above 10 ply fluctuations get less,
>but i do not even get to 10 ply with MTD...
>
>If i have bound 0.100 now which fails high
>and suppose i need to go to 0.400
>(but of course i do not know that i get to 0.400).
>
>If i want to profit optimal from hashtable with MTD then my
>next bound should be 0.101 right?
>
>So you advice me to do 300 researches?
>
>That's *pretty* expensive.

No. Lets say you search 20 ply deep. With 300 researches times 20 ply
you visit 6000 nodes. Is that much? Is is really not an issue.

I also can not follow you millipawn argument. I myself use
centipawns but I tried also milli and dezipawns. There is
a only small difference in efficency (5-10 percent). What
really helps however is full pawn evaluation. With this I
search the starting position to 30 ply full width over night.

>
>>Regards Dan Andersson
>
>Vincent

Rudolf





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