code: def circulant(c):
      """Construct a circulant matrix.
  
      Args:
          c (cupy.ndarray): 1-D array, the first column of the matrix.
  
      Returns:
          cupy.ndarray: A circulant matrix whose first column is ``c``.
  
      .. seealso:: :func:`cupyx.scipy.linalg.toeplitz`
      .. seealso:: :func:`cupyx.scipy.linalg.hankel`
      .. seealso:: :func:`cupyx.scipy.linalg.solve_circulant`
      .. seealso:: :func:`cupyx.scipy.linalg.fiedler`
      .. seealso:: :func:`scipy.linalg.circulant`
      """
      c = c.ravel()
      return _create_toeplitz_matrix(c[::-1], c[:0:-1])
  
imports: import math
  import warnings
  import cupy
  from cupy import _core
  from cupyx.scipy.linalg import _uarray
label_desc: Use image node_id 5 for calling a global function with example usage: circulant(c) and returns: _create_toeplitz_matrix