CosineSimilarity

package com.test.document.parser;

/**
 * Cosine similarity calculator class
 * @author Sandeep Naik
 */
public class CosineSimilarity {

    /**
     * Method to calculate cosine similarity between two documents.
     * @param docVector1 : document vector 1 (a)
     * @param docVector2 : document vector 2 (b)
     * @return 
     */
    public double cosineSimilarity(double[] docVector1, double[] docVector2) {
        double dotProduct = 0.0;
        double magnitude1 = 0.0;
        double magnitude2 = 0.0;
        double cosineSimilarity = 0.0;

        for (int i = 0; i < docVector1.length; i++) //docVector1 and docVector2 must be of same length
        {
            dotProduct += docVector1[i] * docVector2[i];  //a.b
            magnitude1 += Math.pow(docVector1[i], 2);  //(a^2)
            magnitude2 += Math.pow(docVector2[i], 2); //(b^2)
        }

        magnitude1 = Math.sqrt(magnitude1);//sqrt(a^2)
        magnitude2 = Math.sqrt(magnitude2);//sqrt(b^2)

        if (magnitude1 != 0.0 | magnitude2 != 0.0) {
            cosineSimilarity = dotProduct / (magnitude1 * magnitude2);
        } else {
            return 0.0;
        }
        return cosineSimilarity;
    }
}