code: def triang(M, sym=True):
      r"""Return a triangular window.
  
      Parameters
      ----------
      M : int
          Number of points in the output window. If zero or less, an empty
          array is returned.
      sym : bool, optional
          When True (default), generates a symmetric window, for use in filter
          design.
          When False, generates a periodic window, for use in spectral analysis.
  
      Returns
      -------
      w : ndarray
          The window, with the maximum value normalized to 1 (though the value 1
          does not appear if `M` is even and `sym` is True).
  
      See Also
      --------
      bartlett : A triangular window that touches zero
  
      Examples
      --------
      Plot the window and its frequency response:
  
      >>> from cupyx.scipy.signal.windows import triang
      >>> import cupy as cp
      >>> from cupy.fft import fft, fftshift
      >>> import matplotlib.pyplot as plt
  
      >>> window = triang(51)
      >>> plt.plot(cupy.asnumpy(window))
      >>> plt.title("Triangular window")
      >>> plt.ylabel("Amplitude")
      >>> plt.xlabel("Sample")
  
      >>> plt.figure()
      >>> A = fft(window, 2048) / (len(window)/2.0)
      >>> freq = cupy.linspace(-0.5, 0.5, len(A))
      >>> response = cupy.abs(fftshift(A / cupy.abs(A).max()))
      >>> response = 20 * cupy.log10(cupy.maximum(response, 1e-10))
      >>> plt.plot(cupy.asnumpy(freq), cupy.asnumpy(response))
      >>> plt.axis([-0.5, 0.5, -120, 0])
      >>> plt.title("Frequency response of the triangular window")
      >>> plt.ylabel("Normalized magnitude [dB]")
      >>> plt.xlabel("Normalized frequency [cycles per sample]")
  
      """
      if _len_guards(M):
          return cupy.ones(M)
      M, needs_trunc = _extend(M, sym)
  
      w = _triang_kernel(size=M)
  
      return _truncate(w, needs_trunc)
  
imports: import warnings
  from typing import Set
  import cupy
  import numpy
label_desc: Use image node_id 6 for calling a global function with example usage: triang(M, sym) and returns: _truncate, cupy