code: def toeplitz(c, r=None):
      """Construct a Toeplitz matrix.
  
      The Toeplitz matrix has constant diagonals, with ``c`` as its first column
      and ``r`` as its first row. If ``r`` is not given, ``r == conjugate(c)`` is
      assumed.
  
      Args:
          c (cupy.ndarray): First column of the matrix. Whatever the actual shape
              of ``c``, it will be converted to a 1-D array.
          r (cupy.ndarray, optional): First row of the matrix. If None,
              ``r = conjugate(c)`` is assumed; in this case, if ``c[0]`` is real,
              the result is a Hermitian matrix. r[0] is ignored; the first row of
              the returned matrix is ``[c[0], r[1:]]``. Whatever the actual shape
              of ``r``, it will be converted to a 1-D array.
  
      Returns:
          cupy.ndarray: The Toeplitz matrix. Dtype is the same as
          ``(c[0] + r[0]).dtype``.
  
      .. seealso:: :func:`cupyx.scipy.linalg.circulant`
      .. seealso:: :func:`cupyx.scipy.linalg.hankel`
      .. seealso:: :func:`cupyx.scipy.linalg.solve_toeplitz`
      .. seealso:: :func:`cupyx.scipy.linalg.fiedler`
      .. seealso:: :func:`scipy.linalg.toeplitz`
      """
      c = c.ravel()
      r = c.conjugate() if r is None else r.ravel()
      return _create_toeplitz_matrix(c[::-1], r[1:])
  
imports: import math
  import warnings
  import cupy
  from cupy import _core
  from cupyx.scipy.linalg import _uarray
label_desc: Use image node_id 4 for calling a global function with example usage: toeplitz(c, r) and returns: _create_toeplitz_matrix