From b94c00226f52f48f1d2e6a5060325d4327ba27ff Mon Sep 17 00:00:00 2001
From: Gael Guennebaud <g.gael@free.fr>
Date: Tue, 11 Oct 2011 11:28:13 +0200
Subject: [PATCH] make it compatible with Diagonal<>

---
 Eigen/src/Sparse/SparseMatrixBase.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Eigen/src/Sparse/SparseMatrixBase.h b/Eigen/src/Sparse/SparseMatrixBase.h
index 944dbb8e3..182ea0c7e 100644
--- a/Eigen/src/Sparse/SparseMatrixBase.h
+++ b/Eigen/src/Sparse/SparseMatrixBase.h
@@ -44,6 +44,9 @@ template<typename Derived> class SparseMatrixBase : public EigenBase<Derived>
     typedef typename internal::packet_traits<Scalar>::type PacketScalar;
     typedef typename internal::traits<Derived>::StorageKind StorageKind;
     typedef typename internal::traits<Derived>::Index Index;
+    typedef typename internal::add_const_on_value_type_if_arithmetic<
+                         typename internal::packet_traits<Scalar>::type
+                     >::type PacketReturnType;
 
     typedef SparseMatrixBase StorageBaseType;
     typedef EigenBase<Derived> Base;