Re: MLib: How to set preferences for ALS implicit feedback in Collaborative Filtering?

2015-01-20 Thread Xiangrui Meng
The assumption of implicit feedback model is that the unobserved ratings are more likely to be negative. So you may want to add some negatives for evaluation. Otherwise, the input ratings are all 1 and the test ratings are all 1 as well. The baseline predictor, which uses the average rating (that

MLib: How to set preferences for ALS implicit feedback in Collaborative Filtering?

2015-01-16 Thread Zork Sail
I am trying to use Spark MLib ALS with implicit feedback for collaborative filtering. Input data has only two fields `userId` and `productId`. I have **no product ratings**, just info on what products users have bought, that's all. So to train ALS I use: def trainImplicit(ratings:

MLib: How to set preferences for ALS implicit feedback in Collaborative Filtering?

2015-01-16 Thread Julian Ricardo
I am trying to use Spark MLib ALS with implicit feedback for collaborative filtering. Input data has only two fields `userId` and `productId`. I have **no product ratings**, just info on what products users have bought, that's all. So to train ALS I use: def trainImplicit(ratings:

MLib: How to set preferences for ALS implicit feedback in Collaborative Filtering?

2015-01-16 Thread Zork
I am trying to use Spark MLib ALS with implicit feedback for collaborative filtering. Input data has only two fields `userId` and `productId`. I have **no product ratings**, just info on what products users have bought, that's all. So to train ALS I use: def

Re: MLib: How to set preferences for ALS implicit feedback in Collaborative Filtering?

2015-01-16 Thread Sean Owen
On Fri, Jan 16, 2015 at 9:58 AM, Zork Sail zorks...@gmail.com wrote: And then train ALSL: val model = ALS.trainImplicit(ratings, rank, numIter) I get RMSE 0.9, which is a big error in case of preferences taking 0 or 1 value: This is likely the problem. RMSE is not an appropriate