From 032594cee238f39a6b8d200b8e3986c0c3aebdc2 Mon Sep 17 00:00:00 2001
From: Benoit Jacob <jacob.benoit.1@gmail.com>
Date: Fri, 19 Jun 2009 18:51:15 +0200
Subject: [PATCH] forward port fix to #12

---
 Eigen/src/QR/Tridiagonalization.h | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/Eigen/src/QR/Tridiagonalization.h b/Eigen/src/QR/Tridiagonalization.h
index b2381da0c..bd8ff4fe3 100644
--- a/Eigen/src/QR/Tridiagonalization.h
+++ b/Eigen/src/QR/Tridiagonalization.h
@@ -205,6 +205,7 @@ void Tridiagonalization<MatrixType>::_compute(MatrixType& matA, CoeffVectorType&
     // squared norm of the vector v skipping the first element
     RealScalar v1norm2 = matA.col(i).end(n-(i+2)).squaredNorm();
 
+    // FIXME comparing against 1
     if (ei_isMuchSmallerThan(v1norm2,static_cast<Scalar>(1)))
     {
       hCoeffs.coeffRef(i) = 0.;
@@ -253,10 +254,12 @@ void Tridiagonalization<MatrixType>::_compute(MatrixType& matA, CoeffVectorType&
     int i = n-2;
     Scalar v0 = matA.col(i).coeff(i+1);
     RealScalar beta = ei_abs(v0);
-    if (ei_real(v0)>=0.)
+    if (ei_real(v0)>=RealScalar(0))
       beta = -beta;
     matA.col(i).coeffRef(i+1) = beta;
-    hCoeffs.coeffRef(i) = (beta - v0) / beta;
+    // FIXME comparing against 1
+    if(ei_isMuchSmallerThan(beta, Scalar(1))) hCoeffs.coeffRef(i) = Scalar(0);
+    else hCoeffs.coeffRef(i) = (beta - v0) / beta;
   }
   else
   {