From af58d024c36317231f381434b2f9ec82ec042305 Mon Sep 17 00:00:00 2001
From: Sandeep Menon <smenon@ecs.umass.edu>
Date: Thu, 19 May 2011 12:31:03 -0400
Subject: [PATCH] Bug-fix:

 - Account for solution singularity in the CG solver
---
 .../mesquiteMotionSolver/mesquiteMotionSolver.C     | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/src/dynamicMesh/meshMotion/mesquiteMotionSolver/mesquiteMotionSolver.C b/src/dynamicMesh/meshMotion/mesquiteMotionSolver/mesquiteMotionSolver.C
index 7229559d4..d6bebd5c1 100644
--- a/src/dynamicMesh/meshMotion/mesquiteMotionSolver/mesquiteMotionSolver.C
+++ b/src/dynamicMesh/meshMotion/mesquiteMotionSolver/mesquiteMotionSolver.C
@@ -2886,7 +2886,7 @@ label mesquiteMotionSolver::CG
 )
 {
     // Local variables
-    scalar alpha, beta, rho, rhoOld, residual;
+    scalar alpha, beta, rho, rhoOld, residual, wApA;
     label maxIter = x.size(), iter = 0;
 
     reduce(maxIter, sumOp<label>());
@@ -2915,7 +2915,16 @@ label mesquiteMotionSolver::CG
     {
         A(p,w);
 
-        alpha = rho / dot(p,w);
+        wApA = dot(p,w);
+
+        if ((mag(wApA)/norm) < VSMALL)
+        {
+            Info<< " Solution singularity.";
+
+            return iter;
+        }
+
+        alpha = rho / wApA;
 
         forAll (x, i)
         {