21.5.12  Riemann window

The riemann_window command applies the Riemann window function to a sequence or its segment.

• riemann_window takes one mandatory argument and two optional arguments:
  • v, a real vector with length n.
  • Optionally, m, N, a sequence of two integers (by default, m=0 and N=n).
• riemann_window returns the elementwise product of [v_m,v_m+1,…,v_m+N−1] and the vector w of length N defined by

  wk=	⎧ ⎪ ⎪ ⎪ ⎨ ⎪ ⎪ ⎪ ⎩ 1, k= N−1 2 ,        sin(π xk) π xk , otherwise,

  where x_k=2 k/N−1−1 for k=0,1,…,N−1.

Example