Data:
MovieLens is a dataset that is collected by the GroupLens Research Project at the University of Minnesota and made available rating data sets from the MovieLens web site. Download and unzip the MovieLens 100K Dataset (ml-100k.zip). http://grouplens.org/datasets/movielens/ u.data is the dataset. The full dataset contains 100,000 ratings by 943 users on 1682 items. Each user has rated at least 20 movies. Users and items are numbered consecutively from 1. The data is randomly ordered.
We need to build a recommender system (Alternating Least Squares), report the original performance (Mean Square Error), improve the performance using 10-fold cross-validation, and solve the cold-start problem. …