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Subject: Re: Chess Tiger -- Hash dilemma

Author: Jesus de la Villa

Date: 16:27:06 08/23/00

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On August 23, 2000 at 18:59:24, Christophe Theron wrote:

>On August 23, 2000 at 14:30:20, Keith Conary wrote:
>
>>I currently have an active account which runs Chess Tiger automatically on ICC
>>and I've found that running it with the suggested hash table increment of 4-8M
>>works well for fast times against computers only.  But I get several draws and
>>losses to IMs and GMs with the small hash table settings.  After increasing the
>>hash table size to 64M, I get the opposite effect, meaning I crush the humans
>>and lose to the computer at 5 3.  Is there a medium that can be reached in
>>tigers' settings to balance the performance between humans and computers?
>>
>>Thanks
>>
>>Keith
>
>
>Hi Keith!
>
>
>As the author of the engine, I confirm that what you have noticed can only be
>explained by "luck" (noise).
>
>When you play fast time control games with Tiger, you must set the hash table
>size to a low value (between 2Mb and 8Mb). This is because Chess Tiger 12.0
>needs to clear the hash tables before every thinking process, and this takes too
>much time if your hash tables are big.
>
>With really big hash tables, you simply waste 0.2 to 0.5 second per move
>clearing the tables, and after 100 moves you have simply wasted 50 seconds
>clearing them, and will lose on time.
>
>This problem will totally disappear in the next version of the engine (Chess
>Tiger 13), and with the new engine the rule is simple: you give as much RAM for
>hash tables as you can, even if you play game in 10 seconds. Because the new
>engine does not need to clear the hash tables anymore.
>
>But until you get the new engine, you need to set a low hash table size when you
>play fast time control games.
>
>And the hash table size has no effect on the playing strength against humans. As
>far as I know.
>
>
>
>    Christophe

I can guess that you now do a logical clear, not a physical clear, rigth?



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