From c543868c0b016ecd522537b68a25744978376f21 Mon Sep 17 00:00:00 2001
From: Jan Petykiewicz <jan@mpxd.net>
Date: Tue, 14 Jan 2025 21:51:32 -0800
Subject: [PATCH] check for sign=0 case

---
 meanas/fdfd/waveguide_2d.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/meanas/fdfd/waveguide_2d.py b/meanas/fdfd/waveguide_2d.py
index 8ea4846..f2306c1 100644
--- a/meanas/fdfd/waveguide_2d.py
+++ b/meanas/fdfd/waveguide_2d.py
@@ -435,6 +435,7 @@ def _normalized_fields(
     sign = numpy.sign(E_weighted[:,
                                  :max(shape[0] // 2, 1),
                                  :max(shape[1] // 2, 1)].real.sum())
+    assert sign != 0
 
     norm_factor = sign * norm_amplitude * numpy.exp(1j * norm_angle)