[MADLIB-1300] Clarify dep and indep var column names in output table for deep learning minibatch preprocessor

• Type: Improvement
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: v1.16
• Component/s: Module: Utilities
• Assignee: Himanshu Pandey
• Reporter: Frank McQuillan
• Created: 07/Feb/19 19:37
• Updated: 13/Feb/19 22:11
• Resolved: 13/Feb/19 22:11

Description

Follow on to this commit:
Minibatch Preprocessor for Deep learning
https://github.com/apache/madlib/commit/8de32ede33c48d2f4a440f0f639c94a277a359c1

The output table produced by the deep mini-batch preprocessor contains the following columns:

...
dependent_varname	FLOAT8[]. Packed array of dependent variables. If the dependent variable in the source table is categorical, the preprocessor will one-hot encode it.
independent_varname	FLOAT8[]. Packed array of independent variables.
...

This is misleading because these columns contain values not names, so we should rename these columns to:

...
dependent_var
independent_var
...

The output summary table contains the following columns:

dependent_varname	Dependent variable from the source table.
independent_varname	Independent variable from the source table.

This is OK since the columns actually do contain names.

There is a related 2.0 story for the regular mini-batch preprocessor
http://madlib.apache.org/docs/latest/group__grp__minibatch__preprocessing.html
in JIRA https://issues.apache.org/jira/browse/MADLIB-1294 which we don't want to do in 1.16 since it will break semantic versioning