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Subject: Re: Benefit of tablebases seems to be 2 points!?

Author: Eugene Nalimov

Date: 09:42:41 10/13/99

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On October 13, 1999 at 10:17:59, Robert Hyatt wrote:

>On October 13, 1999 at 08:54:43, Jouni Uski wrote:
>
>>On October 13, 1999 at 08:09:13, Robert Hyatt wrote:
>>
>>>On October 13, 1999 at 01:10:30, Harald Faber wrote:
>>>
>>>>On October 13, 1999 at 01:04:05, Jouni Uski wrote:
>>>>
>>>>>Yes from latest SSDF list You see that Hiarcs7.32 with tablebases is only
>>>>>2 points over Hiarcs7 without them. Hmm. Not much benefit from 100+ MB packed
>>>>>data...
>>>>>
>>>>>Jouni
>>>>
>>>>Argh!!!
>>>>The question is how much below would Hiarcs7.32 be WITHOUT the tablebases...
>>>
>>>
>>>Even more important, how would _other_ programs do?  Hiarcs has an apparently
>>>very conservative approach to probing in the search, based on some numbers that
>>>were posted here recently.  It is not surprising that tablebases don't make any
>>>difference given that circumstance.
>>
>>Bob. I just installed Crafty 16.15 (TB version) under Fritz5.32. It's
>>unbelievable how Crafty can access TB dynamically (in search) without slowing
>>NPS much.
>>How is this possible? I remember when I tested same thing with Mchess 7 NPS
>>go down to about 1knps (it was P90 PC then).
>>
>>Jouni
>
>Several things.  (1) Eugene's buffering code is quite good;  (2) if you only
>probe _after_ a capture, and only when pieces <= 5, the probes aren't done
>a ridiculous number of times.  (3) I did a _lot_ of testing to find a way to
>steadily increase the depth at which probes occur without smashing the search
>back to 1K nps as you mentioned.

(4) My indexing schema is optimized for probing by chess programs - I am trying
to increase locality of references. That helps a lot, as after first probe there
are good chances that block that was read contains results for second, third,
... probes.

Eugene

>And don't forget that a CD will kill me.  And if you really want to see it
>probe, try 10K rpm LVDS drives at 80 mbytes/second transfer rate.



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