Re: Collaborative Filtering Implicit Feedback Impl.

2016-12-05 Thread Sean Owen
As I recall, it is in there in the math, but doesn't appear as an explicit term in the computation. You don't actually materialize the 0 input or the "c=1" corresponding to them. Or: do you have a computation that agrees with the paper but not this code? Put another way, none of this would

Re: Collaborative Filtering Implicit Feedback Impl.

2016-12-05 Thread Jerry Lam
Hi Sean, I agree there is no need for that if the implementation actually assigns c=1 for all missing ratings but from the current implementation of ALS, I don't think it is doing that. The idea is that for missing ratings, they are assigned to c=1 (in the paper) and they do contribute to the

Re: Collaborative Filtering Implicit Feedback Impl.

2016-12-05 Thread Sean Owen
That doesn't mean this 0 value is literally included in the input. There's no need for that. On Tue, Dec 6, 2016 at 4:24 AM Jerry Lam wrote: > Hi Sean, > > I'm referring to the paper (http://yifanhu.net/PUB/cf.pdf) Section 2: > " However, with implicit feedback it would be

Re: Collaborative Filtering Implicit Feedback Impl.

2016-12-05 Thread Jerry Lam
Hi Sean, I'm referring to the paper (http://yifanhu.net/PUB/cf.pdf) Section 2: " However, with implicit feedback it would be natural to assign values to all rui variables. If no action was observed rui is set to zero, thus meaning in our examples zero watching time, or zero purchases on record."

Re: Collaborative Filtering Implicit Feedback Impl.

2016-12-05 Thread Sean Owen
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 wrote: > Hello spark users and developers, > > I read the paper from Yahoo about CF with implicit feedback and other > papers

Collaborative Filtering Implicit Feedback Impl.

2016-12-05 Thread Jerry Lam
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