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Subject: Re: question about hash tables

Author: Miguel A. Ballicora

Date: 13:30:06 05/08/02

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On May 08, 2002 at 16:15:58, martin fierz wrote:

>On May 08, 2002 at 15:27:33, Uri Blass wrote:
>
>>On May 07, 2002 at 19:26:43, martin fierz wrote:
>>
>><snipped>
>>>i used to use a two-table approach in my checkers program, with one table being
>>>used for all nodes which were <N plies from the root, the other for >=N. in the
>>>first table, i replaced with deeper draft only, in the second, i always
>>>replaced. i changed it to a single table after finding no significant
>>>difference; in the single table i have a hash bucket size of 2,
>>
>>I do not understand.
>>
>>What does a hash buket size of 2 means?
>
>you get an index to save your hashentry to from your hashkey. instead of saving
>1 entry at every index, you can save N there - N is the bucket size. the idea is
>that if the bucket is full, you can choose one of the N entries you want to
>overwrite - instead of overwriting what may have been a valuable entry, you look
>which of them is the least valuable, and overwrite that one.

It is possible to do exactly the same as in the two table approach, but I always
thought that with a bucket it will be more "cache friendly". Maybe
is not such a big deal. I will have to try it one day.

Regards,
Miguel

>
>>Note that I do not understand what is the reason for using 3 integers for
>>depth,flags and value when it is possible to compress these 3 numbers to a
>>single 32 bit integer in order to have more entries in the hash tables.
>just so it's clear...
>
>aloha
>  martin



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