add logger

meanas/fdfd/waveguide_cyl.py

@@ -10,6 +10,7 @@ As the z-dependence is known, all the functions in this file assume a 2D grid
 
 from typing import Any
 from collections.abc import Sequence
+import logging
 
 import numpy
 from numpy.typing import NDArray, ArrayLike
@@ -20,6 +21,9 @@ from ..fdmath.operators import deriv_forward, deriv_back
 from ..eigensolvers import signed_eigensolve, rayleigh_quotient_iteration
 
 
+logger = logging.getLogger(__name__)
+
+
 def cylindrical_operator(
         omega: complex,
         dxes: dx_lists_t,