class DbClustering::DistanceMetrics::EuclideanDistance

Public Class Methods

new(min_dimensions: 1) click to toggle source
# File lib/distance_metrics/euclidean_distance.rb, line 6
def initialize(min_dimensions: 1)
  @min_dimensions = min_dimensions
end

Public Instance Methods

distance(vector1, vector2) click to toggle source
# File lib/distance_metrics/euclidean_distance.rb, line 10
def distance(vector1, vector2)
  vector1_array = vector1.array_for_comparison(vector2)
  vector2_array = vector2.array_for_comparison(vector1)

  if vector1_array.count != vector2_array.count
    raise "Vectors with different sizes cannot be compared"
  end

  if vector1_array.count < @min_dimensions
    return Float::INFINITY
  end

  # see here for calculation formula: http://en.wikipedia.org/wiki/Euclidean_distance
  sum = 0
  vector1_array.count.times do |i|
    sum += (vector1_array[i] - vector2_array[i]) ** 2
  end
  sqrt sum
end