Java Cosine Similarity cosineSimilarity(String[] tkn0, String[] tkn1)

Description

cosine Similarity

License

Open Source License

Declaration

public static double cosineSimilarity(String[] tkn0, String[] tkn1) 

Method Source Code

//package com.java2s;
//License from project: Open Source License 

import java.util.*;
import java.util.Map.Entry;

public class Main {
    public static double cosineSimilarity(String[] tkn0, String[] tkn1) {

        HashMap<String, int[]> map = new HashMap<String, int[]>();
        for (int i = 0; i < tkn0.length; i++) {
            String t = tkn0[i].toLowerCase();
            if (!map.containsKey(t)) {
                map.put(t, new int[2]);
            }/*from  w w  w .  j a  v a 2s . co m*/
            map.get(t)[0]++;
        }
        for (int i = 0; i < tkn1.length; i++) {
            String t = tkn1[i].toLowerCase();
            if (!map.containsKey(t)) {
                map.put(t, new int[2]);
            }
            map.get(t)[1]++;
        }
        double dot = 0;
        double norma = 0;
        double normb = 0;
        for (Entry<String, int[]> e : map.entrySet()) {
            int[] v = e.getValue();
            dot += v[0] * v[1];
            norma += v[0] * v[0];
            normb += v[1] * v[1];
        }
        norma = Math.sqrt(norma);
        normb = Math.sqrt(normb);
        if (dot == 0) {
            return 0;
        } else {
            return dot / (norma * normb);
        }
    }
}

Related

1. cosineSim(double[] a, double[] b)
2. cosineSimilarity(double[] vector1, double[] vector2)
3. cosineSimilarity(double[] x, double[] y)
4. cosineSimilarity(float[] f1, float[] f2)
5. cosineSimilarity(float[] vectorA, float[] vectorB)