From bcae5348920fe010dce15349c60bd87d05b7ee7a Mon Sep 17 00:00:00 2001
From: Peter Munch <peterrmuench@gmail.com>
Date: Thu, 9 Jul 2020 20:01:26 +0200
Subject: [PATCH] Add check to step-12

---
 examples/step-12/step-12.cc | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/examples/step-12/step-12.cc b/examples/step-12/step-12.cc
index fcec1e2c1f..70a6bd64c6 100644
--- a/examples/step-12/step-12.cc
+++ b/examples/step-12/step-12.cc
@@ -126,7 +126,9 @@ namespace Step12
     Point<dim> wind_field;
     wind_field(0) = -p(1);
     wind_field(1) = p(0);
-    wind_field /= wind_field.norm();
+
+    if (wind_field.norm() > 1e-10)
+      wind_field /= wind_field.norm();
 
     return wind_field;
   }
-- 
2.39.5