a) multinomial is supported b) the --categories is there for the command line version which is mostly for demo purposes
c) ridge regression originally meant L2 regularization. Nowadays people use it to describe either L1 or L2, but Lasso would be a better word for L1. d) regularization is independent of link function. Mahout only supports inverse logistic link function (i.e. logistic regression). Other links are easy to install. Linear regression is very easy to support, but since there is a strong initial solution (using Cholesky decomposition = L2 regularization), I would recommend a from-scratch implementation. e) Hector's work has added some additional flexibility, mostly untried as yet. On Thu, Sep 29, 2011 at 12:01 PM, Dmitriy Lyubimov <[email protected]>wrote: > If by ridge estimator you imply l1 regularization, afaik you can choose > from > l1 and l2 gularization. > > Also I guess ridge implies identity link function, but I don't think mahout > is limited just to ridge and lasso. > > Ted knows for sure. > On Sep 28, 2011 7:27 PM, "Keith Thompson" <[email protected]> wrote: > > Thanks Dmitriy. I also found the Mahout in Action book and checked there. > > In one of the examples it seems there is a --categories option which > allows > > the user to specify the number of categories for classification purposes > > (although all of the examples in the text are binary classifications). I > am > > curious though as to whether the algorithm employed in Mahout uses ridge > > estimators or not. > > > > Keith > > > > On Wed, Sep 28, 2011 at 10:18 PM, Dmitriy Lyubimov <[email protected] > >wrote: > > > >> As far as I know, Mahout implementation does multinomial classification. > >> On Sep 28, 2011 8:47 AM, "Keith Thompson" <[email protected]> > wrote: > >> > Is the version of the logistic regression classifier in Mahout for > >> binomial > >> > classification only or can it be used for multinomial as well? > >> > > >> > Regards, > >> > Keith > >> > > > > > > > > -- > > *Keith Thompson* > > Graduate Research Associate, Xerox Corporation > > SUNY Research Foundation > > Dept. of Systems Science and Industrial Engineering > > Binghamton University > > work: 585-422-6587 > > cell: 607-793-6203 >
