43 lines
809 B
Ruby
43 lines
809 B
Ruby
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class AbstractMeasure
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def initialize(attributes)
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@attributes = attributes
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end
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def distance(point1, point2)
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raise "You should probably override this method!"
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end
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end
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class EuclideanDistance < AbstractMeasure
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def distance(p1,p2)
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sum_of_squares = 0
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p1.each_with_index do |p1_coord,index|
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if (@attributes.include?(index))
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sum_of_squares += (p1_coord - p2[index]) ** 2
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end
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end
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Math.sqrt( sum_of_squares )
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end
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end
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class JensenShannonDistance < AbstractMeasure
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def distance(p1, p2)
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m = []
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p1.each_index {|i| m[i] = (p1[i]+p2[i]) / 2 }
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return ( 0.5*kl(p1, m) + 0.5*kl(p2, m) )
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end
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def kl(p1, p2)
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sum = 0.0
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p1.each_index do |i|
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if (@attributes.include?(i))
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if (p1[i] > 0)
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sum += p1[i] * Math.log( p1[i] / p2[i] )
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end
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end
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end
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return sum
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end
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end
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