class Array

Public Instance Methods

covariance() click to toggle source

# 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