From: | "Stewart Ben (RBAU/EQS4) *" <Ben(dot)Stewart(at)au(dot)bosch(dot)com> |
---|---|
To: | <pgsql-sql(at)postgresql(dot)org> |
Subject: | Re: SEVEN cross joins?!?!? |
Date: | 2005-10-13 02:02:42 |
Message-ID: | E253BDD7F008244585AEE87AF8F0224F116C7ACB@cl-mail01.au.bosch.com |
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Lists: | pgsql-sql |
> Splitting locations into subsets (like 2,2,3) doesn't work
> because it is possible that low values in one location can be offset
by
> high values in another location, and still result in an excellent
combo.
>
> The good news is these suggestions got me thinking outside
> the box. I think I can program a modified brute-force that bypasses
> large numbers of combos early. It might still be too large/slow, so
I'd be
> interested in finding more info about these "smarter algorithms" in
option
Could you define an view with a calculated field, say, 2 * a1 + 6 * a2 +
3 * a3, and then use this aggregate to score the individual rows? I
haven't looked at the exact nature of the problem, but if you're
multiplying a table by itself, it may be worth redefining the problem in
terms of a simple ranking algorithm, define a column to calculate this,
then sort by that column.
Best regards,
Ben Stewart
--
Robert Bosch (Australia) Pty. Ltd.
Engineering Quality Services, Student Software Engineer (RBAU/EQS4)
Locked Bag 66 - Clayton South, VIC 3169 - AUSTRALIA
Tel: +61 3 9541-7002 Fax: +61 3 9541-7700
mailto:ben(dot)stewart(at)au(dot)bosch(dot)com
http://www.bosch.com.au/
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