From 32397c7be16fb56656f1dc2f39c7bedf5778b4de Mon Sep 17 00:00:00 2001
From: Martin Kronbichler <kronbichler@lnm.mw.tum.de>
Date: Thu, 1 Jun 2017 16:09:03 +0200
Subject: [PATCH] Avoid division by zero.

---
 source/fe/mapping_q_generic.cc | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/source/fe/mapping_q_generic.cc b/source/fe/mapping_q_generic.cc
index 5338286124..0320705483 100644
--- a/source/fe/mapping_q_generic.cc
+++ b/source/fe/mapping_q_generic.cc
@@ -107,11 +107,8 @@ namespace internal
         const double discriminant = b*b - 4*a*c;
         // exit if the point is not in the cell (this is the only case where the
         // discriminant is negative)
-        if (discriminant < 0.0)
-          {
-            AssertThrow (false,
-                         (typename Mapping<spacedim,spacedim>::ExcTransformationFailed()));
-          }
+        AssertThrow (discriminant > 0.0,
+                     (typename Mapping<spacedim,spacedim>::ExcTransformationFailed()));
 
         double eta1;
         double eta2;
-- 
2.39.5