From ef817306252f33e844eb789ef850778de84f47cb Mon Sep 17 00:00:00 2001
From: Gael Guennebaud <g.gael@free.fr>
Date: Tue, 12 May 2015 18:38:43 +0200
Subject: [PATCH] Ignore denormal numbers in selfadjoint eigensolver.

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

diff --git a/Eigen/src/Eigenvalues/SelfAdjointEigenSolver.h b/Eigen/src/Eigenvalues/SelfAdjointEigenSolver.h
index 8240b9465..fff331d33 100644
--- a/Eigen/src/Eigenvalues/SelfAdjointEigenSolver.h
+++ b/Eigen/src/Eigenvalues/SelfAdjointEigenSolver.h
@@ -474,11 +474,14 @@ ComputationInfo computeFromTridiagonal_impl(DiagType& diag, SubDiagType& subdiag
   Index end = n-1;
   Index start = 0;
   Index iter = 0; // total number of iterations
-
+  
+  typedef typename DiagType::RealScalar RealScalar;
+  const RealScalar considerAsZero = (std::numeric_limits<RealScalar>::min)();
+  
   while (end>0)
   {
     for (Index i = start; i<end; ++i)
-      if (internal::isMuchSmallerThan(abs(subdiag[i]),(abs(diag[i])+abs(diag[i+1]))))
+      if (internal::isMuchSmallerThan(abs(subdiag[i]),(abs(diag[i])+abs(diag[i+1]))) || abs(subdiag[i]) <= considerAsZero)
         subdiag[i] = 0;
 
     // find the largest unreduced block