In the paper “Large-Scale Parallel Collaborative Filtering for the Netflix Prize”, the following steps are described for ALS:
Step 1 Initialize matrix M by assigning the average rating for that movie as the first row, and small random numbers for the remaining entries. Step 2 Fix M, Solve U by minimizing the objective function (the sum of squared errors); Step 3 Fix U, solve M by minimizing the objective function similarly; Step 4 Repeat Steps 2 and 3 until a stopping criterion is satisfied. Does spark take the average rating for the movie as the first row? I've looked through the source code, but I can't see the average rating being calculated for the movie. Many thanks, Chris --------------------------------------------------------------------- To unsubscribe e-mail: [email protected]
