Class: CanberraDistance

Inherits:
Object
  • Object
show all
Defined in:
lib/canberra_distance.rb

Class Method Summary collapse

Class Method Details

.calculate(vector1, vector2) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/canberra_distance.rb', line 2

def self.calculate(vector1, vector2)
  raise ArgumentError.new(
    "Cardinality mismatch when calculating Canberra distance."
  ) if vector1.size != vector2.size

  pairs = vector1.zip(vector2)

  numerators   = pairs.map { |a, b| (a - b).abs.to_f }
  denominators = pairs.map { |a, b| a.abs + b.abs    }

  distances = numerators.zip(denominators).map do |n, d|
    d.zero? ? 0 : n / d
  end

  distances.inject(:+)
end