Computes a
neigbhorhood consisting of all users whose similarity to the given user meets
or exceeds a certain threshold. Similarity is defined by UserSimilarity
instance provided at the time of construction ThresholdUserNeighborhood
instance.
Following
example shows usage of NearestNUserNeighborhood.
Let’s say I
had following data.
customers.csv
1,1,3 1,2,1 1,4,5 1,5,3 1,9,3 1,10,2 2,1,2 2,3,2 2,4,1 2,7,5 3,1,5 3,2,1 3,3,1 3,6,1 3,8,1 4,1,1 4,2,1 4,6,3 4,7,1 4,9,2 5,2,1 5,3,3 5,6,5 5,10,3 6,1,1 6,2,4 6,3,4 6,7,2 6,8,3 7,1,3 7,2,3 7,3,1 7,5,3 7,6,3 7,7,3 8,1,1 8,3,3 8,4,5 8,8,1 8,9,2 9,4,2 9,6,5 9,8,3 9,9,3 10,2,5 10,3,1 10,4,2 10,5,1 10,9,4 11,2,3 11,4,2 11,5,2 11,8,1 12,1,1 12,3,4 12,7,3 12,8,2 13,1,3 13,2,4 13,3,2 13,5,3 13,9,3 14,2,3 14,3,2 14,5,1 14,7,1 14,8,5 14,9,2 15,1,3 15,2,2 15,3,2 15,6,5 15,7,1 15,9,3 16,2,2 16,3,4 16,6,1 16,7,3 16,10,1 17,3,1 17,4,3 17,7,4 17,8,4 18,3,3 18,5,2 18,6,3 18,9,1 18,10,2 19,1,1 19,2,5 19,6,2 19,7,2 19,8,3 19,10,3 20,1,2 20,2,2 20,3,1 20,4,4 20,8,1
20,8,1 means
user 20 bought item 8 and rated 1.
import java.io.File; import java.io.IOException; import org.apache.mahout.cf.taste.common.TasteException; import org.apache.mahout.cf.taste.impl.model.file.FileDataModel; import org.apache.mahout.cf.taste.impl.neighborhood.ThresholdUserNeighborhood; import org.apache.mahout.cf.taste.impl.similarity.EuclideanDistanceSimilarity; import org.apache.mahout.cf.taste.model.DataModel; import org.apache.mahout.cf.taste.neighborhood.UserNeighborhood; public class ThresholdUserNeighborhoodEx { public static String dataFile = "/Users/harikrishna_gurram/customer.csv"; public static void main(String args[]) throws IOException, TasteException { DataModel model = new FileDataModel(new File(dataFile)); EuclideanDistanceSimilarity similarity = new EuclideanDistanceSimilarity( model); UserNeighborhood neighborhood = new ThresholdUserNeighborhood(0.5, similarity, model); long[] neighbors = neighborhood.getUserNeighborhood(1); System.out.println("Neighbors for user 1 are"); for (long user : neighbors) { System.out.print(user + " "); } } }
Output
Neighbors
for user 1 are
5 16 20 15
5 16 20 15
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