User 3 gave a recommendation to item 107. User 5 did not rate 107.
On Thu, Feb 13, 2014 at 1:57 AM, Suresh M <suresh4mas...@gmail.com> wrote: > user 5 has given rating for all 5 books, > So there will be no recommendations for him. > > > > On 12 February 2014 08:55, jiangwen jiang <jiangwen...@gmail.com> wrote: > > > 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! > > >