From 3eb0abe907ce6286fda8fafca11dcb7e4ad3e792 Mon Sep 17 00:00:00 2001
From: Hrvoje Jasak <h.jasak@wikki.co.uk>
Date: Sun, 27 Feb 2011 02:19:31 +0000
Subject: [PATCH] Robustness improvement

---
 .../primitives/Tensor/tensor/tensor.C         | 20 +++++--------------
 1 file changed, 5 insertions(+), 15 deletions(-)

diff --git a/src/OpenFOAM/primitives/Tensor/tensor/tensor.C b/src/OpenFOAM/primitives/Tensor/tensor/tensor.C
index 5f466159c..248e52bf7 100644
--- a/src/OpenFOAM/primitives/Tensor/tensor/tensor.C
+++ b/src/OpenFOAM/primitives/Tensor/tensor/tensor.C
@@ -317,24 +317,14 @@ vector eigenValues(const symmTensor& t)
 
         // If there is a zero root
         if (mag(c) < SMALL)
-//         if (mag(c) < 1.0e-100)
         {
-            scalar disc = sqr(a) - 4*b;
+            const scalar disc = Foam::max(sqr(a) - 4*b, 0.0);
 
-            if (disc >= -SMALL)
-            {
-                scalar q = -0.5*sqrt(max(scalar(0), disc));
+            scalar q = -0.5*sqrt(max(scalar(0), disc));
 
-                i = 0;
-                ii = -0.5*a + q;
-                iii = -0.5*a - q;
-            }
-            else
-            {
-                FatalErrorIn("eigenValues(const tensor&)")
-                    << "zero and complex eigenvalues in tensor: " << t
-                    << abort(FatalError);
-            }
+            i = 0;
+            ii = -0.5*a + q;
+            iii = -0.5*a - q;
         }
         else
         {