Class: DbClustering::DistanceMetrics::EuclideanDistance

Inherits:
Object
  • Object
show all
Includes:
Math
Defined in:
lib/distance_metrics/euclidean_distance.rb

Instance Method Summary collapse

Constructor Details

#initialize(min_dimensions: 1) ⇒ EuclideanDistance

Returns a new instance of EuclideanDistance.



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# File 'lib/distance_metrics/euclidean_distance.rb', line 6

def initialize(min_dimensions: 1)
  @min_dimensions = min_dimensions
end

Instance Method Details

#distance(vector1, vector2) ⇒ Object 



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# 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