code: def polycompanion(c):
      """Computes the companion matrix of c.
  
      Args:
          c (cupy.ndarray): 1-D array of polynomial coefficients
              ordered from low to high degree.
  
      Returns:
          cupy.ndarray: Companion matrix of dimensions (deg, deg).
  
      .. seealso:: :func:`numpy.polynomial.polynomial.polycompanion`
  
      """
      [c] = cupy.polynomial.polyutils.as_series([c])
      deg = c.size - 1
      if deg == 0:
          raise ValueError(
              "Series must have maximum degree of at least 1."
          )
      matrix = cupy.eye(deg, k=-1, dtype=c.dtype)
      matrix[:, -1] -= c[:-1] / c[-1]
      return matrix
  
imports: import cupy
label_desc: Use image node_id 2 for calling a global function with example usage: polycompanion(c) and returns: matrix