Avoid division by zero.

diff --git a/source/fe/mapping_q_generic.cc b/source/fe/mapping_q_generic.cc
index 53382861240df084c8eaa3e4eaae47328b6eebd5..0320705483c8e4cb70c9148e235c10072ab63eee 100644 (file)
--- 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;