From ec39a39cb6fb0e3b1863e26b955087f0d8bbe560 Mon Sep 17 00:00:00 2001
From: Gael Guennebaud <g.gael@free.fr>
Date: Thu, 15 Jul 2010 20:00:34 +0200
Subject: [PATCH] fix LLT for zero matrix

---
 Eigen/src/Cholesky/LLT.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/Eigen/src/Cholesky/LLT.h b/Eigen/src/Cholesky/LLT.h
index b7bf58e63..ffee76012 100644
--- a/Eigen/src/Cholesky/LLT.h
+++ b/Eigen/src/Cholesky/LLT.h
@@ -132,7 +132,8 @@ void LLT<MatrixType>::compute(const MatrixType& a)
     m_isInitialized = true;
     return;
   }
-  m_matrix.col(0).end(size-1) = a.row(0).end(size-1).adjoint() / ei_real(m_matrix.coeff(0,0));
+  if(ei_real(m_matrix.coeff(0,0))>0)
+    m_matrix.col(0).end(size-1) = a.row(0).end(size-1).adjoint() / ei_real(m_matrix.coeff(0,0));
   for (int j = 1; j < size; ++j)
   {
     x = ei_real(a.coeff(j,j)) - m_matrix.row(j).start(j).squaredNorm();