code: func Blackman(L int) []float64 {
  	r := make([]float64, L)
  	LF := float64(L)
  	alpha := 0.16
  	a0 := (1 - alpha) / 2.0
  	a1 := 0.5
  	a2 := alpha / 2.0
  
  	for i := 0; i < L; i++ {
  		iF := float64(i)
  		r[i] = a0 - (a1 * math.Cos((twoPi*iF)/(LF-1))) + (a2 * math.Cos((fourPi*iF)/(LF-1)))
  	}
  	return r
  }
docs: // Blackman generates a Blackman window of the requested size
  // See https://en.wikipedia.org/wiki/Window_function#Blackman_windows