Re: scoring differences between bitmasks

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От Ben
Тема Re: scoring differences between bitmasks
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Msg-id F8B339D3-2D35-4C9B-9FCC-776CA4776C87@silentmedia.com
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Ответ на scoring differences between bitmasks  (Ben <bench@silentmedia.com>)
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Hrm, I don't understand. Can you give me an example with some
reasonably sized vectors?

On Oct 2, 2005, at 10:59 AM, Todd A. Cook wrote:

> Hi,
>
> Try breaking the vector into 4 bigint columns and building a multi-
> column
> index, with index columns going from the most evenly distributed to
> the
> least.  Depending on the distribution of your data, you may only
> need 2
> or 3 columns in the index.  If you can cluster the table in that
> order,
> it should be really fast.  (This structure is a tabular form of a
> linked
> trie.)
>
> -- todd
>
>
> Ben wrote:
>
>> Yes, that's the straightforward way to do it. But given that my
>> vectors are 256 bits in length, and that I'm going to eventually
>> have  about 4 million of them to search through, I was hoping
>> greater minds  than mine had figured out how to do it faster, or
>> how compute some  kind of indexing....... somehow.
>


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