From 476beed7f837cbed9abc401f685c1882936fa959 Mon Sep 17 00:00:00 2001
From: Gael Guennebaud <g.gael@free.fr>
Date: Mon, 22 Jun 2015 16:51:45 +0200
Subject: bug #1017: apply Christoph's patch preventing underflows in
 makeHouseholder

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

(limited to 'Eigen/src/Householder')

diff --git a/Eigen/src/Householder/Householder.h b/Eigen/src/Householder/Householder.h
index 32112af9b..4c1f499a1 100644
--- a/Eigen/src/Householder/Householder.h
+++ b/Eigen/src/Householder/Householder.h
@@ -75,8 +75,9 @@ void MatrixBase<Derived>::makeHouseholder(
   
   RealScalar tailSqNorm = size()==1 ? RealScalar(0) : tail.squaredNorm();
   Scalar c0 = coeff(0);
+  const RealScalar tol = (std::numeric_limits<RealScalar>::min)();
 
-  if(tailSqNorm == RealScalar(0) && numext::imag(c0)==RealScalar(0))
+  if(tailSqNorm <= tol && numext::abs2(numext::imag(c0))<=tol)
   {
     tau = RealScalar(0);
     beta = numext::real(c0);
-- 
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