Re: Question about mllib als's implicit training

2015-02-12 Thread Crystal Xing
HI Sean, I am reading the paper of implicit training. Collaborative Filtering for Implicit Feedback Datasets http://labs.yahoo.com/files/HuKorenVolinsky-ICDM08.pdf It mentioned To this end, let us introduce a set of binary variables p_ui, which indicates the preference of user u to item i. The

Re: Question about mllib als's implicit training

2015-02-12 Thread Sean Owen
Where there is no user-item interaction, you provide no interaction, not an interaction with strength 0. Otherwise your input is fully dense. On Thu, Feb 12, 2015 at 11:09 PM, Crystal Xing crystalxin...@gmail.com wrote: Hi, I have some implicit rating data, such as the purchasing data. I read

Re: Question about mllib als's implicit training

2015-02-12 Thread Sean Owen
This all describes how the implementation operates, logically. The matrix P is never formed, for sure, certainly not by the caller. The implementation actually extends to handle negative values in R too but it's all taken care of by the implementation. On Thu, Feb 12, 2015 at 11:29 PM, Crystal

Re: Question about mllib als's implicit training

2015-02-12 Thread Crystal Xing
Many thanks! On Thu, Feb 12, 2015 at 3:31 PM, Sean Owen so...@cloudera.com wrote: This all describes how the implementation operates, logically. The matrix P is never formed, for sure, certainly not by the caller. The implementation actually extends to handle negative values in R too but

Question about mllib als's implicit training

2015-02-12 Thread Crystal Xing
Hi, I have some implicit rating data, such as the purchasing data. I read the paper about the implicit training algorithm used in spark and it mentioned the for user-prodct pairs which do not have implicit rating data, such as no purchase, we need to provide the value as 0. This is different