module MoreMath::Sequence::MovingAverage

def simple_moving_average(n)
  n < 1 and raise ArgumentError, 'n < 1, has to be >= 1'
  n <= @elements.size or raise ArgumentError,
    'n > #elements, has to be <= #elements'
  avg = []
  0.upto(@elements.size - n) do |i|
    sum = 0.0
    i.upto(i + n - 1) do |j|
      sum += @elements[j].to_f
    end
    avg << sum / n
  end
  avg
end