[lsst-dm-stack-users] How to calculate RMS, sigma-clipped RMS on DM Winter2013 Stripe82 forced photometry

[Michael Wood-Vasey]

Hi Simon,

I'd like to calculate the RMS, the chisq, and a sigma-clipped RMS on the DM Winter2013 Stripe 82 forced photometry that was announced and described at the LSST Splinter meeting this past Sunday at AAS.

http://dev.lsstcorp.org/trac/wiki/DC/Winter2013

I've been interacting with and using the database and I understand connections and the matching.  But what would be the most efficient way to calculate the above aggregate quantities?  Should I implement a cursor in my SQL query (easy to write, probably painfully slow to run), is there some support for such aggregate functions in the MySQL server (I checked and STDEV wasn't available), or should I talk to you about efficient ways to reprocess the raw files that fed these tables?

Thank you kindly,
Michael



--
Michael Wood-Vasey, Assistant Professor
Department of Physics and Astronomy
University of Pittsburgh, Pittsburgh, PA 15260
http://www.phyast.pitt.edu/~wmwv