From: | "John D(dot) Burger" <john(at)mitre(dot)org> |
---|---|
To: | ABHANG RANE <arane(at)indiana(dot)edu> |
Cc: | Postgres General <pgsql-general(at)postgresql(dot)org> |
Subject: | Re: cube operations |
Date: | 2007-05-17 02:15:02 |
Message-ID: | 71868041-8ECF-49A7-8B9C-D460FEEA1CB3@mitre.org |
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Lists: | pgsql-general |
ABHANG RANE wrote:
> I have a array column which has 12 real values in it. Basically
> these values represent co-ordinates in 12 dimensions for a
> substance. My main need is to find substances similar to a
> particular compound. Now I can do by calculating differences with
> each array in the whole table. But the table has millions of rows.
> So I need some kinda higher dimensional index.
Is there any particular reason you're using an array? If every row
has all twelve values, I'd just make them columns. Then I could use
a multi-column index.
> I have read about the cube operation in postgre, can it be extended
> to 12 dimensions or something like that.
I have no experience with CUBE, but I think it's just a kind of
summarization aggregate.
It sounds like you want the Nearest Neighbor(s) of your "particular
compound". You might to read about that:
http://en.wikipedia.org/wiki/Nearest_neighbor_search
- John Burger
G63
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