Class: Array

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

Instance Method Summary collapse

Instance Method Details

#covariance ⇒ Object 



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# File 'lib/array.rb', line 3

def covariance
  sx, sy, sp = 0.0, 0.0, 0.0
  return sx if empty?
target = first.respond_to?(:to_ary) ? self :
self.class.new(size) { |i| [i + 1, at(i)] }
target.each { |x, y|
  sx += x
  sy += y
  sp += x * y
}
(sp - sx * sy / size) / size
end