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Subject: Re: Dynamic TB Access & MChess

Author: Robert Hyatt

Date: 07:34:33 10/17/98

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On October 17, 1998 at 07:49:52, Kai Lübke wrote:

>On October 16, 1998 at 15:52:56, Ernst A. Heinz wrote:
>
>>On October 16, 1998 at 11:41:21, Mark Young wrote:
>>>
>>>** MChess played its games so far with "dynamic TB access" activated which is
>>>discouraged by Marty. It's likely it would have played better without it.
>>
>>Isn't it only discouraged if you use the TBs from CD?
>>
>>Should be not worse than for any other program that probes TBs at interior
>>nodes if you copy the Tbs to your harddisk.
>
>I had them on HD. However, the problem seems to be that MChess slows down a lot
>during heavy TB access (8 Knps or less on P6-233, about 14 Knps on PII-400)
>which seems to outweigh the positive information from the TB's.
>Crafty is not affected this much since it's 3-4 times faster than MChess.
>
>>Maybe it is worse for MChess because it extends much more aggressively, thus
>>going deeper in selected lines than others and hitting on the TBs more often.
>
>Exactly. Crafty hardly ever goes below 1/2 its usual speed, MChess often goes to
>1/10.
>
>---
>Shep


this logic seems wrong, however.  IE if I search 4x faster than Mchess, I am
going to search 4x the captures, and do 4x the disk I/O as well.  It might be
more basic than a nps different.  It *might* be that the code written by SJE
does a better job at caching to avoid disk I/O than what Marty is using.  But
in any case, a faster program ought to get hurt more when probing in the tree
than a slower program, since the fast program is going to probe more, and disk
speeds are constant...



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