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Subject: Re: Size of PawnHashTable

Author: Ron Murawski

Date: 08:35:51 11/08/02

Go up one level in this thread


On November 08, 2002 at 07:40:45, Tony Werten wrote:

>On November 08, 2002 at 04:14:34, Daniel Clausen wrote:
>
>>On November 07, 2002 at 18:03:52, Ron Murawski wrote:
>>
>>>On November 07, 2002 at 16:57:04, Martin Bauer wrote:
>>>
>>>>On November 07, 2002 at 16:08:49, Tony Werten wrote:
>>>>
>>>>>Somewhere from 8Mb you will get a 99,9% hitrate after a few seconds.
>>>>
>>>>Memory usage depends on waht I am storing, can you tell me a number of Hashtable
>>>>entries?
>>>>
>>>
>>>One less than a power of two (aka Mesenne number) entries is best, a prime
>>>number of entries is supposed to be acceptable.
>>
>>Shouldn't it be the opposite? "prime number is best but 2^n-1 is acceptable"?
>
>Don't think so. With a big table, collisions are not probable so no real
>difference there. But: 2^n-1 can be calculated with a cheap AND and prime most
>be done with an  expensive mod.
>
>BTW the AND number is 2^n-1 so the number of entries is 2^n
>


My power-of-two code was written yesterday and you've already found a bug!
Thanks, Tony

Ron


>Tony
>
>>
>>Sargon



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