tree fe072c8128b16b4d614f5ac4c8c1f6bd9a50c4bc
parent 34ca6188ecb51577d5994699636a231d2615c548
author Orhan Kislal <okislal@pivotal.io> 1526514874 -0700
committer Orhan Kislal <okislal@pivotal.io> 1526514874 -0700

Statistics: Add grouping support for correlation functions

JIRA: MADLIB-1128

This commit adds grouping support to correlation and covariance
functions in MADlib stats. Changes include relevant queries to do the
same.
This commit also has refactor changes to a helper function in
utilities.py_in.

Co-authored-by: Jingyi Mei <jmei@pivotal.io>
Co-authored-by: Nikhil Kak <nkak@pivotal.io>
Co-authored-by: Nandish Jayaram <njayaram@apache.org>
Co-authored-by: Frank McQuillan <fmcquillan@pivotal.io>