Hi, all: I try to user mahout api to make recommendations, but I find some userId has no recommendations, why?
here is my code public static void main(String args[]) throws Exception { String inFile = "F:\\hadoop\\data\\recsysinput.txt"; DataModel dataModel = new FileDataModel(new File(inFile)); UserSimilarity userSimilarity = new PearsonCorrelationSimilarity(dataModel); UserNeighborhood userNeighborhood = new NearestNUserNeighborhood(100, userSimilarity, dataModel); Recommender recommender = new GenericUserBasedRecommender(dataModel, userNeighborhood, userSimilarity); for (int i = 1; i < 5; i++) { List<RecommendedItem> recommendations = recommender.recommend(i, 1); System.out.println("recommend for user:" + i); for (RecommendedItem recommendation : recommendations) { System.out.println(recommendation); } } } input data(recsysinput.txt): 1,101,5.0 1,102,3.0 1,103,2.5 2,101,2 2,102,2.5 2,103,5 2,104,2 3,101,2.5 3,104,4 3,105,4.5 3,107,5 4,101,5 4,103,3 4,104,4.5 4,106,4 5,101,4 5,102,3 5,103,2 5,104,4 5,105,3.5 5,106,4 output: recommend for user:1 RecommendedItem[item:104, value:5.0] recommend for user:2 RecommendedItem[item:106, value:4.0] recommend for user:3 RecommendedItem[item:106, value:4.0] recommend for user:4 RecommendedItem[item:105, value:5.0] recommend for user:5 UserId 5 has no recommendations, is it right? Can I get some recommendations for userId 5, even if the recommendation results are not good enough? thanks Regards!