[MADLIB-1092] Elastic Net gives inconsistent results with grouping

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: v1.11
• Component/s: Module: Regularized Regression
• Assignee: Unassigned
• Reporter: Nandish Jayaram
• Created: 21/Apr/17 01:08
• Updated: 01/May/17 21:06
• Resolved: 27/Apr/17 21:43

Description

Elastic net train seems to be giving incorrect results when used with grouping.

Steps:

• Run elastic net (train) on a table and obtain a model (M1).
• Create a new table with all rows in the original input table and assign group value 1 for it.
• Replicate the rows in the table and assign group value 2 for the replicated rows.
• Run the elastic net train function with grouping while keeping the same optimization parameters for the function.

Result:

• The model (for each group) when run with grouping is different from the model M1.
• The model for both the groups is the same, but not same as M1.

Issue Links

• links to: GitHub Pull Request #126