code: def funTransQuadF(k, s):
      
      sqrtk = np.sqrt(complex(k))
      a = np.cos(sqrtk * s)
      b = np.sin(sqrtk * s) / sqrtk
      c = -sqrtk * np.sin(sqrtk * s)
      d = np.cos(sqrtk * s)
      return np.matrix([[a.real, b.real], [c.real, d.real]], dtype=np.double)
docs: Focusing quad in X, defocusing in Y
  
      :param k: k1, in [T/m]
      :param s: width, in [m]
      :return: 2x2 numpy array