tree be0c4c755ca0e62a8844694400619f46503f50bd
parent 4b0c37714c17a4aae8759a4dd05e59f0c94ba598
author Nandish Jayaram <njayaram@apache.org> 1493052363 -0700
committer Nandish Jayaram <njayaram@apache.org> 1493426840 -0700

Bugfix: Elastic net gives inconsistent result

JIRA: MADLIB-1092

- Elastic net used to consider the number of rows as the total number
of rows in the table even when grouping was used. This fix changes
that to consider the number of rows in a group while computing IGD.
- Elastic net used to consider mean and standard deviation for both
independent and dependent variables based on the entire table even
when grouping was used. This is now computed based on a group,
which is used to computed the scaled data when standardize=TRUE
for Gaussian IGD.
- One approximation still remains. During gradient computation (C++),
every value in the independent variable (for each dimension) is
subtracted with the mean computed based on the entire table and
not groups. This approximiation was adopted since it is messy to
pass group specific mean values for every row in the table to the
C++ layer.

Closes #126