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Subject: Re: Hashtables: is larger always better?

Author: Antonio Dieguez

Date: 00:37:08 09/23/01

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On September 23, 2001 at 02:50:59, Uri Blass wrote:

>On September 22, 2001 at 23:42:29, James Swafford wrote:
>
>>On September 22, 2001 at 22:17:06, Uri Blass wrote:
>>
>>>On September 22, 2001 at 19:08:06, Torstein Hall wrote:
>>>
>>>>On September 22, 2001 at 18:29:46, Andreas De Troy wrote:
>>>>
>>
>>>If the hash tables are very big then the probability for hash collision can
>>>increase and if there are enough hash collisions the result can be a bad move.
>>>
>>>Uri
>>
>>Why do you think the size of the table has any bearing on the number
>>of collisions?  The number of collisions is a function of the
>>"uniqueness" of your key, not how many entries are in your table.
>
>let take an extreme case:
>suppose there is only one entry in your hash tables and you use 64 bit numbers.
>
>The probability for wrong hash collision is 1/2^64 for every new node after the
>first node.
>
>If you have 1000000 entries in your hash tables and the hash tables are full
>then the probability for hash collision is 1000000/2^64 for every new node.

Hi both. Excuse me.

Sure! (what were I doing writing some silly things... I can't resist to say that
my bro was asking the comp)

be well.

>>
>>Maybe my definition of a collision is different than the norm:  I
>>define a collision as a match of the entire key between different
>>positions, not a match of the portion of the key used as a probe into
>>the table.
>
>I also define a collision as a match of the full key(2 different positions with
>the same 64 bit number).
>
>Uri



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