Basic Distance Calculation of two Vectors with Scala

DistanceMetrics.scala

import math._

object DistanceMetrics {
  /**
    * distance method helps get the Euclidean Distance between two vectors
    * Euclidean Distance tests the space betweeen two Vectors and the result is
    * between 0 and 2 where:
    * 0 means the space between them is 0
    * 2 meanns the space between the two vector is at maximum
    * @param xs
    * @param ys
    * @return
    */
  def distance(xs: Array[Double], ys: Array[Double]): Double = {
    sqrt(
      (xs zip ys).map { case (x, y) => pow(y - x, 2) }.sum)
  }

  /**
    * Compute the Cosine Similarity between Two Vectors.
    * It makes use of the dot_product and magnitute function
    * Answer of the Cosine Similarity should range between -1 and 1
    * Where -1 means the Similarity between the two arrays is 180 and
    * 1 means there Similarity is at 0
    * @param xs: X - Array[Double] to compare
    * @param ys Y - Array[DOuble] to compare
    * @return
    */
  def cosine_similarity(xs: Array[Double], ys: Array[Double]): Double = {
    require(xs.length == ys.length)
    dot_product(xs, ys)/(get_magnitude(xs) * get_magnitude(ys))
  }

  /**
    * Compute the Dot product of two 1-D Array[Double]
    * @param xs
    * @param ys
    * @return
    */
  def dot_product(xs: Array[Double], ys: Array[Double]): Double = {
    xs.zip(ys).map { case (x, y) => x*y}.sum
  }

  def get_magnitude(xs: Array[Double]): Double=
    sqrt(
      xs.map(i => i * i).sum
    )
}