hacking contrib/intarray could help you. You need to add function which
return the number of overlapped elements.
Oleg
On Wed, 16 May 2007, John D. Burger wrote:
> 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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Regards,
Oleg
_____________________________________________________________
Oleg Bartunov, Research Scientist, Head of AstroNet (www.astronet.ru),
Sternberg Astronomical Institute, Moscow University, Russia
Internet: oleg@sai.msu.su, http://www.sai.msu.su/~megera/
phone: +007(495)939-16-83, +007(495)939-23-83