Interesting patch. I did a quick review looking only into the patch file. The "sum of variances" variable contains the "sum of squared differences" instead, I think.
And a very minor aspect: The term "standard deviation" in your code stands for (corrected) sample standard deviation, I think, because you devide by n-1 instead of n to keep the estimator unbiased. How about mentioning the prefix "sample" to indicate this beiing the estimator? And I'm sure I'm missing C specifics (again) (or it's the reduced patch file scope), but you introduce sqrtd, but sqrt is called? VlG Arne -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
