If you want to select specific variable combinations by hand, then you will
need to modify the dataset before passing it to the ML algorithm.  The
DataFrame API should make that easy to do.

If you want to have an ML algorithm select variables automatically, then I
would recommend using L1 regularization for now and possibly elastic net
after 1.4 is release, per DB's suggestion.

If you want detailed model statistics similar to what R provides, I've
created a JIRA for discussing how we should add that functionality to
MLlib.  Those types of stats will be added incrementally, but feedback
would be great for prioritization:
https://issues.apache.org/jira/browse/SPARK-7674

To answer your question: "How are the weights calculated: is there a
correlation calculation with the variable of interest?"
--> Weights are calculated as with all logistic regression algorithms, by
using convex optimization to minimize a regularized log loss.

Good luck!
Joseph

On Fri, May 22, 2015 at 1:07 PM, DB Tsai <dbt...@dbtsai.com> wrote:

> In Spark 1.4, Logistic Regression with elasticNet is implemented in ML
> pipeline framework. Model selection can be achieved through high
> lambda resulting lots of zero in the coefficients.
>
> Sincerely,
>
> DB Tsai
> -------------------------------------------------------
> Blog: https://www.dbtsai.com
>
>
> On Fri, May 22, 2015 at 1:19 AM, SparknewUser
> <melanie.galloi...@gmail.com> wrote:
> > I am new in MLlib and in Spark.(I use Scala)
> >
> > I'm trying to understand how LogisticRegressionWithLBFGS and
> > LogisticRegressionWithSGD work.
> > I usually use R to do logistic regressions but now I do it on Spark
> > to be able to analyze Big Data.
> >
> > The model only returns weights and intercept. My problem is that I have
> no
> > information about which variable is significant and which variable I had
> > better
> > to delete to improve my model. I only have the confusion matrix and the
> AUC
> > to evaluate the performance.
> >
> > Is there any way to have information about the variables I put in my
> model?
> > How can I try different variable combinations, do I have to modify the
> > dataset
> > of origin (e.g. delete one or several columns?)
> > How are the weights calculated: is there a correlation calculation with
> the
> > variable
> > of interest?
> >
> >
> >
> > --
> > View this message in context:
> http://apache-spark-user-list.1001560.n3.nabble.com/MLlib-how-to-get-the-best-model-with-only-the-most-significant-explanatory-variables-in-LogisticRegr-tp22993.html
> > Sent from the Apache Spark User List mailing list archive at Nabble.com.
> >
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