Re: scoring differences between bitmasks

From: Ben <bench(at)silentmedia(dot)com>
To: "Todd A(dot) Cook" <tcook(at)blackducksoftware(dot)com>
Cc: Postgresql-General mailing list <pgsql-general(at)postgresql(dot)org>
Subject: Re: scoring differences between bitmasks
Date: 2005-10-02 19:46:33
Message-ID: E609BD70-26A2-472B-9B6D-DE2462C39C1E@silentmedia.com
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Sure, but unless I can figure out some way to choose a small number
of vectors, I'm left with computing the full N^2 set. Given that I'm
shooting for N to be 4 million or larger, that's a lot of data to
store.....

On Oct 2, 2005, at 12:14 PM, Todd A. Cook wrote:

> Ben wrote:
>
>> Just the number of bits, not which ones. Basically, the hamming
>> distance.
>>
>
> I see. Could you pre-compute the bit counts for the vectors in the
> table?
> You could count the bits in the search vector as Martijn suggested,
> and then
> do a lookup based on the count.
>
> -- todd
>
>
>
>

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