From 4eaa06a60f53448a9d97a81b3470f26661b075a7 Mon Sep 17 00:00:00 2001
From: Henry Weller <http://cfd.direct>
Date: Sat, 26 Nov 2016 20:49:54 +0000
Subject: [PATCH] tensor::eigenValues: Test the magnitude of 'QQ' before
 dividing by it.

Resolves bug-report http://bugs.openfoam.org/view.php?id=2351
---
 src/OpenFOAM/primitives/Tensor/tensor/tensor.C | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/OpenFOAM/primitives/Tensor/tensor/tensor.C b/src/OpenFOAM/primitives/Tensor/tensor/tensor.C
index cadbef6a9..2d8da5e71 100644
--- a/src/OpenFOAM/primitives/Tensor/tensor/tensor.C
+++ b/src/OpenFOAM/primitives/Tensor/tensor/tensor.C
@@ -123,7 +123,7 @@ Foam::vector Foam::eigenValues(const tensor& t)
         }
 
         // Two identical roots and one distinct root
-        else if (mag(PPP/QQ - 1) < SMALL)
+        else if (mag(QQ) > SMALL && mag(PPP/QQ - 1) < SMALL)
         {
             scalar sqrtP = sqrt(P);
             scalar signQ = sign(Q);