What are you referring to in what paper? implicit input would never materialize 0s for missing values.
On Tue, Dec 6, 2016 at 3:42 AM Jerry Lam <chiling...@gmail.com> wrote: > Hello spark users and developers, > > I read the paper from Yahoo about CF with implicit feedback and other > papers using implicit feedbacks. Their implementation require to set the > missing rating with 0. That is for unobserved ratings, the confidence for > those is set to 1 (c=1). Therefore, the matrix to be factorized is a dense > matrix. > > I read the source code of the ALS implementation in spark (version 1.6.x) > for implicit feedback. Apparently, it ignores rating that is 0 (Line 1159 > in ALS.scala). It could be a mistake or it could be an optimization. Just > want to see if anyone steps on this yet. > > Best Regards, > > Jerry >
