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Subject: Re: Two-Tier Hashtable vs. One-Tier

Author: Stuart Cracraft

Date: 16:42:53 09/21/04

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On September 21, 2004 at 18:03:13, Michael Henderson wrote:

>On September 21, 2004 at 17:36:47, Stuart Cracraft wrote:
>
>>Hi -- this past weekend I switched from single-tier replace
>>always to two-tier place 1st tier in 2nd if incoming position
>>is searched to a >= depth than currently stored at hash entry
>>and store incoming position in 1st tier, otherwise always replace
>>2nd tier if depth is.
>>
>>This is represented by the actual code below.
>>
>>After doing this, I expected least the same result or slightly
>>better (than 250/300 on Win-at-Chess). Instead I scored 248/300
>>(consistently) with Two-Tier and 250/300 consistently with One-Tier.
>
>Excuse me for the simple explanation, but 2-tier works much better at deeper
>depths/long search time trees.  2-tier is slightly slower in the 1 second
>searches due to the extra memory lookups.  It is best at handling filled and
>active hash tables.  I'm thinking 1-tier is fast and all you need for 1 second
>searches...
>
>Michael

Great -- I'm sure you're right.



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