Computes the euclidean distance between 2 double value lists - Java java.lang

Java examples for java.lang:double

  1. HOME
  2. Java
  3. java.lang
  4. double

Description

Computes the euclidean distance between 2 double value lists

Demo Code


//package com.java2s;

public class Main {


    public static double euclideanDistance(double[] l1, double[] l2,
            boolean weighted) {
        if (weighted) {
            return weightedEuclideanDistance(l1, l2);
        } else {/*from  w w  w .  ja  v a 2 s .  c o  m*/
            return standardEuclideanDistance(l1, l2);
        }
    }

    /**
     * Computes the euclidean distance between 2 lists with more weight on first elements.
     * 
     * @param l1
     *            list of doubles
     * @param l2
     *            list of doubles
     * @return euclidean distance
     */
    public static double weightedEuclideanDistance(double[] l1, double[] l2) {

        if (l1.length != l2.length) {
            throw new IllegalArgumentException(
                    "Both list must have the same number of elements");
        }

        double sum = 0;

        for (int i = 0; i < l1.length; i++) {
            double delta = (l2[i] - l1[i]);
            double weightRatio = (1 / (i + 1));
            sum += delta * delta * weightRatio;
        }

        return Math.sqrt(sum);
    }

    /**
     * Computes the euclidean distance between 2 lists
     * 
     * @param l1
     *            list of doubles
     * @param l2
     *            list of doubles
     * @return euclidean distance
     */
    public static double standardEuclideanDistance(double[] l1, double[] l2) {

        if (l1.length != l2.length) {
            throw new IllegalArgumentException(
                    "Both list must have the same number of elements");
        }

        double sum = 0;

        for (int i = 0; i < l1.length; i++) {
            double delta = (l2[i] - l1[i]);
            sum += delta * delta;
        }

        return Math.sqrt(sum);
    }
}

Related Tutorials