diff --git a/Eigen/Sparse b/Eigen/Sparse
index ce65d4d..168511c 100644
--- a/Eigen/Sparse
+++ b/Eigen/Sparse
@@ -79,6 +79,7 @@
 #include "src/Sparse/SparseMatrix.h"
 #include "src/Sparse/SparseVector.h"
 #include "src/Sparse/CoreIterators.h"
+#include "src/Sparse/SparseRedux.h"
 #include "src/Sparse/SparseProduct.h"
 #include "src/Sparse/TriangularSolver.h"
 #include "src/Sparse/SparseLLT.h"
diff --git a/Eigen/src/Sparse/CoreIterators.h b/Eigen/src/Sparse/CoreIterators.h
index ebe0bf8..b1d113a 100644
--- a/Eigen/src/Sparse/CoreIterators.h
+++ b/Eigen/src/Sparse/CoreIterators.h
@@ -33,21 +33,21 @@
 {
     typedef typename Derived::Scalar Scalar;
   public:
-    InnerIterator(const Derived& mat, int outer)
+    EIGEN_STRONG_INLINE InnerIterator(const Derived& mat, int outer)
       : m_matrix(mat), m_inner(0), m_outer(outer), m_end(mat.rows())
     {}
 
-    Scalar value() const
+    EIGEN_STRONG_INLINE Scalar value() const
     {
       return (Derived::Flags&RowMajorBit) ? m_matrix.coeff(m_outer, m_inner)
                                           : m_matrix.coeff(m_inner, m_outer);
     }
 
-    InnerIterator& operator++() { m_inner++; return *this; }
+    EIGEN_STRONG_INLINE InnerIterator& operator++() { m_inner++; return *this; }
 
-    int index() const { return m_inner; }
+    EIGEN_STRONG_INLINE int index() const { return m_inner; }
 
-    operator bool() const { return m_inner < m_end && m_inner>=0; }
+    EIGEN_STRONG_INLINE operator bool() const { return m_inner < m_end && m_inner>=0; }
 
   protected:
     const Derived& m_matrix;
@@ -61,7 +61,7 @@
 {
   public:
 
-    InnerIterator(const Transpose& trans, int outer)
+    EIGEN_STRONG_INLINE InnerIterator(const Transpose& trans, int outer)
       : MatrixType::InnerIterator(trans.m_matrix, outer)
     {}
 };
@@ -74,7 +74,7 @@
     typedef typename _MatrixTypeNested::InnerIterator MatrixTypeIterator;
   public:
 
-    InnerIterator(const Block& block, int outer)
+    EIGEN_STRONG_INLINE InnerIterator(const Block& block, int outer)
       : m_iter(block.m_matrix,(Block::Flags&RowMajor) ? block.m_startRow.value() + outer : block.m_startCol.value() + outer),
         m_start( (Block::Flags&RowMajor) ? block.m_startCol.value() : block.m_startRow.value()),
         m_end(m_start + ((Block::Flags&RowMajor) ? block.m_blockCols.value() : block.m_blockRows.value())),
@@ -84,24 +84,24 @@
         ++m_iter;
     }
 
-    InnerIterator& operator++()
+    EIGEN_STRONG_INLINE InnerIterator& operator++()
     {
       ++m_iter;
       return *this;
     }
 
-    Scalar value() const { return m_iter.value(); }
+    EIGEN_STRONG_INLINE Scalar value() const { return m_iter.value(); }
 
-    int index() const { return m_iter.index() - m_offset; }
+    EIGEN_STRONG_INLINE int index() const { return m_iter.index() - m_offset; }
 
-    operator bool() const { return m_iter && m_iter.index()<m_end; }
+    EIGEN_STRONG_INLINE operator bool() const { return m_iter && m_iter.index()<m_end; }
 
   protected:
     MatrixTypeIterator m_iter;
     int m_start;
     int m_end;
     int m_offset;
-}; 
+};
 
 template<typename MatrixType, int BlockRows, int BlockCols, int PacketAccess>
 class Block<MatrixType, BlockRows, BlockCols, PacketAccess, IsSparse>::InnerIterator
@@ -111,7 +111,7 @@
     typedef typename _MatrixTypeNested::InnerIterator MatrixTypeIterator;
   public:
 
-    InnerIterator(const Block& block, int outer)
+    EIGEN_STRONG_INLINE InnerIterator(const Block& block, int outer)
       : m_iter(block.m_matrix,(Block::Flags&RowMajor) ? block.m_startRow.value() + outer : block.m_startCol.value() + outer),
         m_start( (Block::Flags&RowMajor) ? block.m_startCol.value() : block.m_startRow.value()),
         m_end(m_start + ((Block::Flags&RowMajor) ? block.m_blockCols.value() : block.m_blockRows.value())),
@@ -121,17 +121,17 @@
         ++m_iter;
     }
 
-    InnerIterator& operator++()
+    EIGEN_STRONG_INLINE InnerIterator& operator++()
     {
       ++m_iter;
       return *this;
     }
 
-    Scalar value() const { return m_iter.value(); }
+    EIGEN_STRONG_INLINE Scalar value() const { return m_iter.value(); }
 
-    int index() const { return m_iter.index() - m_offset; }
+    EIGEN_STRONG_INLINE int index() const { return m_iter.index() - m_offset; }
 
-    operator bool() const { return m_iter && m_iter.index()<m_end; }
+    EIGEN_STRONG_INLINE operator bool() const { return m_iter && m_iter.index()<m_end; }
 
   protected:
     MatrixTypeIterator m_iter;
@@ -148,13 +148,13 @@
     typedef typename _MatrixTypeNested::InnerIterator MatrixTypeIterator;
   public:
 
-    InnerIterator(const CwiseUnaryOp& unaryOp, int outer)
+    EIGEN_STRONG_INLINE InnerIterator(const CwiseUnaryOp& unaryOp, int outer)
       : m_iter(unaryOp.m_matrix,outer), m_functor(unaryOp.m_functor), m_id(-1)
     {
       this->operator++();
     }
 
-    InnerIterator& operator++()
+    EIGEN_STRONG_INLINE InnerIterator& operator++()
     {
       if (m_iter)
       {
@@ -169,11 +169,11 @@
       return *this;
     }
 
-    Scalar value() const { return m_value; }
+    EIGEN_STRONG_INLINE Scalar value() const { return m_value; }
 
-    int index() const { return m_id; }
+    EIGEN_STRONG_INLINE int index() const { return m_id; }
 
-    operator bool() const { return m_id>=0; }
+    EIGEN_STRONG_INLINE operator bool() const { return m_id>=0; }
 
   protected:
     MatrixTypeIterator m_iter;
@@ -182,23 +182,54 @@
     int m_id;
 };
 
+template<typename T> struct ei_is_scalar_product { enum { ret = false }; };
+template<typename T> struct ei_is_scalar_product<ei_scalar_product_op<T> > { enum { ret = true }; };
+
+template<typename BinaryOp, typename Lhs, typename Rhs, typename Derived>
+class CwiseBinaryOpInnerIterator;
+
 template<typename BinaryOp, typename Lhs, typename Rhs>
 class CwiseBinaryOp<BinaryOp,Lhs,Rhs>::InnerIterator
+  : public CwiseBinaryOpInnerIterator<BinaryOp,Lhs,Rhs, typename CwiseBinaryOp<BinaryOp,Lhs,Rhs>::InnerIterator>
 {
+    typedef CwiseBinaryOpInnerIterator<
+      BinaryOp,Lhs,Rhs, typename CwiseBinaryOp<BinaryOp,Lhs,Rhs>::InnerIterator> Base;
+  public:
     typedef typename CwiseBinaryOp::Scalar Scalar;
     typedef typename ei_traits<CwiseBinaryOp>::_LhsNested _LhsNested;
     typedef typename _LhsNested::InnerIterator LhsIterator;
     typedef typename ei_traits<CwiseBinaryOp>::_RhsNested _RhsNested;
     typedef typename _RhsNested::InnerIterator RhsIterator;
+//   public:
+    EIGEN_STRONG_INLINE InnerIterator(const CwiseBinaryOp& binOp, int outer)
+      : Base(binOp.m_lhs,binOp.m_rhs,binOp.m_functor,outer)
+    {}
+};
+
+template<typename BinaryOp, typename Lhs, typename Rhs, typename Derived>
+class CwiseBinaryOpInnerIterator
+{
+    typedef CwiseBinaryOp<BinaryOp,Lhs,Rhs> ExpressionType;
+    typedef typename ExpressionType::Scalar Scalar;
+    typedef typename ei_traits<ExpressionType>::_LhsNested _LhsNested;
+//     typedef typename ei_traits<ExpressionType>::LhsIterator LhsIterator;
+    typedef typename ei_traits<ExpressionType>::_RhsNested _RhsNested;
+//     typedef typename ei_traits<ExpressionType>::RhsIterator RhsIterator;
+//     typedef typename ei_traits<CwiseBinaryOp>::_LhsNested _LhsNested;
+    typedef typename _LhsNested::InnerIterator LhsIterator;
+//     typedef typename ei_traits<CwiseBinaryOp>::_RhsNested _RhsNested;
+    typedef typename _RhsNested::InnerIterator RhsIterator;
+//     enum { IsProduct = ei_is_scalar_product<BinaryOp>::ret };
   public:
 
-    InnerIterator(const CwiseBinaryOp& binOp, int outer)
-      : m_lhsIter(binOp.m_lhs,outer), m_rhsIter(binOp.m_rhs,outer), m_functor(binOp.m_functor), m_id(-1)
+    EIGEN_STRONG_INLINE CwiseBinaryOpInnerIterator(const _LhsNested& lhs, const _RhsNested& rhs,
+      const BinaryOp& functor, int outer)
+      : m_lhsIter(lhs,outer), m_rhsIter(rhs,outer), m_functor(functor), m_id(-1)
     {
       this->operator++();
     }
 
-    InnerIterator& operator++()
+    EIGEN_STRONG_INLINE Derived& operator++()
     {
       if (m_lhsIter && m_rhsIter && (m_lhsIter.index() == m_rhsIter.index()))
       {
@@ -223,14 +254,14 @@
       {
         m_id = -1;
       }
-      return *this;
+      return *static_cast<Derived*>(this);
     }
 
-    Scalar value() const { return m_value; }
+    EIGEN_STRONG_INLINE Scalar value() const { return m_value; }
 
-    int index() const { return m_id; }
+    EIGEN_STRONG_INLINE int index() const { return m_id; }
 
-    operator bool() const { return m_id>=0; }
+    EIGEN_STRONG_INLINE operator bool() const { return m_id>=0; }
 
   protected:
     LhsIterator m_lhsIter;
@@ -239,5 +270,65 @@
     Scalar m_value;
     int m_id;
 };
+/*
+template<typename T, typename Lhs, typename Rhs, typename Derived>
+class CwiseBinaryOpInnerIterator<ei_scalar_product_op<T>,Lhs,Rhs,Derived>
+{
+    typedef typename CwiseBinaryOp::Scalar Scalar;
+    typedef typename ei_traits<CwiseBinaryOp>::_LhsNested _LhsNested;
+    typedef typename _LhsNested::InnerIterator LhsIterator;
+    typedef typename ei_traits<CwiseBinaryOp>::_RhsNested _RhsNested;
+    typedef typename _RhsNested::InnerIterator RhsIterator;
+  public:
+
+    EIGEN_STRONG_INLINE CwiseBinaryOpInnerIterator(const CwiseBinaryOp& binOp, int outer)
+      : m_lhsIter(binOp.m_lhs,outer), m_rhsIter(binOp.m_rhs,outer), m_functor(binOp.m_functor)//, m_id(-1)
+    {
+      //this->operator++();
+      while (m_lhsIter && m_rhsIter && m_lhsIter.index() != m_rhsIter.index())
+      {
+        if (m_lhsIter.index() < m_rhsIter.index())
+          ++m_lhsIter;
+        else
+          ++m_rhsIter;
+      }
+    }
+
+    EIGEN_STRONG_INLINE Derived& operator++()
+    {
+//       m_id = -1;
+      asm("#beginwhile");
+      while (m_lhsIter && m_rhsIter)
+      {
+        if (m_lhsIter.index() == m_rhsIter.index())
+        {
+//           m_id = m_lhsIter.index();
+          //m_value = m_functor(m_lhsIter.value(), m_rhsIter.value());
+          ++m_lhsIter;
+          ++m_rhsIter;
+          break;
+        }
+        else if (m_lhsIter.index() < m_rhsIter.index())
+          ++m_lhsIter;
+        else
+          ++m_rhsIter;
+      }
+      asm("#endwhile");
+      return *static_cast<Derived*>(this);
+    }
+
+    EIGEN_STRONG_INLINE Scalar value() const { return m_functor(m_lhsIter.value(), m_rhsIter.value()); }
+
+    EIGEN_STRONG_INLINE int index() const { return m_lhsIter.index(); }
+
+    EIGEN_STRONG_INLINE operator bool() const { return m_lhsIter && m_rhsIter; }
+
+  protected:
+    LhsIterator m_lhsIter;
+    RhsIterator m_rhsIter;
+    const BinaryOp& m_functor;
+//     Scalar m_value;
+//     int m_id;
+};*/
 
 #endif // EIGEN_COREITERATORS_H
diff --git a/Eigen/src/Sparse/SparseMatrixBase.h b/Eigen/src/Sparse/SparseMatrixBase.h
index 4ea9593..d70c992 100644
--- a/Eigen/src/Sparse/SparseMatrixBase.h
+++ b/Eigen/src/Sparse/SparseMatrixBase.h
@@ -167,6 +167,49 @@
       return s;
     }
 
+//     template<typename OtherDerived>
+//     Scalar dot(const MatrixBase<OtherDerived>& other) const
+//     {
+//       EIGEN_STATIC_ASSERT_VECTOR_ONLY(Derived)
+//       EIGEN_STATIC_ASSERT_VECTOR_ONLY(OtherDerived)
+//       EIGEN_STATIC_ASSERT((ei_is_same_type<Scalar, typename OtherDerived::Scalar>::ret),
+//         YOU_MIXED_DIFFERENT_NUMERIC_TYPES__YOU_NEED_TO_USE_THE_CAST_METHOD_OF_MATRIXBASE_TO_CAST_NUMERIC_TYPES_EXPLICITLY)
+//
+//       ei_assert(derived().size() == other.size());
+//       // short version, but the assembly looks more complicated because
+//       // of the CwiseBinaryOp iterator complexity
+//       // return res = (derived().cwise() * other.derived().conjugate()).sum();
+//
+//       // optimized, generic version
+//       typename Derived::InnerIterator i(derived(),0);
+//       typename OtherDerived::InnerIterator j(other.derived(),0);
+//       Scalar res = 0;
+//       while (i && j)
+//       {
+//         if (i.index()==j.index())
+//         {
+// //           std::cerr << i.value() << " * " << j.value() << "\n";
+//           res += i.value() * ei_conj(j.value());
+//           ++i; ++j;
+//         }
+//         else if (i.index()<j.index())
+//           ++i;
+//         else
+//           ++j;
+//       }
+//       return res;
+//     }
+//
+//     Scalar sum() const
+//     {
+//       Scalar res = 0;
+//       for (typename Derived::InnerIterator iter(*this,0); iter; ++iter)
+//       {
+//         res += iter.value();
+//       }
+//       return res;
+//     }
+
   protected:
 
     bool m_isRValue;
diff --git a/Eigen/src/Sparse/SparseRedux.h b/Eigen/src/Sparse/SparseRedux.h
new file mode 100644
index 0000000..746ae2f
--- /dev/null
+++ b/Eigen/src/Sparse/SparseRedux.h
@@ -0,0 +1,70 @@
+// This file is part of Eigen, a lightweight C++ template library
+// for linear algebra. Eigen itself is part of the KDE project.
+//
+// Copyright (C) 2008 Gael Guennebaud <g.gael@free.fr>
+//
+// Eigen is free software; you can redistribute it and/or
+// modify it under the terms of the GNU Lesser General Public
+// License as published by the Free Software Foundation; either
+// version 3 of the License, or (at your option) any later version.
+//
+// Alternatively, you can redistribute it and/or
+// modify it under the terms of the GNU General Public License as
+// published by the Free Software Foundation; either version 2 of
+// the License, or (at your option) any later version.
+//
+// Eigen is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+// FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License or the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License and a copy of the GNU General Public License along with
+// Eigen. If not, see <http://www.gnu.org/licenses/>.
+
+#ifndef EIGEN_SPARSEREDUX_H
+#define EIGEN_SPARSEREDUX_H
+
+
+template<typename Derived, int Vectorization, int Unrolling>
+struct ei_sum_impl<Derived, Vectorization, Unrolling, IsSparse>
+{
+  typedef typename Derived::Scalar Scalar;
+  static Scalar run(const Derived& mat)
+  {
+    ei_assert(mat.rows()>0 && mat.cols()>0 && "you are using a non initialized matrix");
+    Scalar res = 0;
+    for (int j=0; j<mat.outerSize(); ++j)
+      for (typename Derived::InnerIterator iter(mat,j); iter; ++iter)
+        res += iter.value();
+    return res;
+  }
+};
+
+template<typename Derived1, typename Derived2, int Vectorization, int Unrolling>
+struct ei_dot_impl<Derived1, Derived2, Vectorization, Unrolling, IsSparse>
+{
+  typedef typename Derived1::Scalar Scalar;
+  static Scalar run(const Derived1& v1, const Derived2& v2)
+  {
+    ei_assert(v1.size()>0 && "you are using a non initialized vector");
+    typename Derived1::InnerIterator i(v1,0);
+    typename Derived2::InnerIterator j(v2,0);
+    Scalar res = 0;
+    while (i && j)
+    {
+      if (i.index()==j.index())
+      {
+        res += i.value() * ei_conj(j.value());
+        ++i; ++j;
+      }
+      else if (i.index()<j.index())
+        ++i;
+      else
+        ++j;
+    }
+    return res;
+  }
+};
+
+#endif // EIGEN_SPARSEREDUX_H
diff --git a/Eigen/src/Sparse/SparseVector.h b/Eigen/src/Sparse/SparseVector.h
index 2f80b6e..7a2ce70 100644
--- a/Eigen/src/Sparse/SparseVector.h
+++ b/Eigen/src/Sparse/SparseVector.h
@@ -272,6 +272,28 @@
       return s;
     }
 
+    // this specialized version does not seems to be faster
+//     Scalar dot(const SparseVector& other) const
+//     {
+//       int i=0, j=0;
+//       Scalar res = 0;
+//       asm("#begindot");
+//       while (i<nonZeros() && j<other.nonZeros())
+//       {
+//         if (m_data.index(i)==other.m_data.index(j))
+//         {
+//           res += m_data.value(i) * ei_conj(other.m_data.value(j));
+//           ++i; ++j;
+//         }
+//         else if (m_data.index(i)<other.m_data.index(j))
+//           ++i;
+//         else
+//           ++j;
+//       }
+//       asm("#enddot");
+//       return res;
+//     }
+
     /** Destructor */
     inline ~SparseVector() {}
 };
diff --git a/Eigen/src/Sparse/SuperLUSupport.h b/Eigen/src/Sparse/SuperLUSupport.h
index 6f554fa..c9acfc2 100644
--- a/Eigen/src/Sparse/SuperLUSupport.h
+++ b/Eigen/src/Sparse/SuperLUSupport.h
@@ -114,13 +114,13 @@
   }
 };
 
-template<typename Scalar, int Rows, int Cols, int StorageOrder, int MRows, int MCols>
-struct SluMatrixMapHelper<Matrix<Scalar,Rows,Cols,StorageOrder,MRows,MCols> >
+template<typename Scalar, int Rows, int Cols, int Options, int MRows, int MCols>
+struct SluMatrixMapHelper<Matrix<Scalar,Rows,Cols,Options,MRows,MCols> >
 {
-  typedef Matrix<Scalar,Rows,Cols,StorageOrder,MRows,MCols> MatrixType;
+  typedef Matrix<Scalar,Rows,Cols,Options,MRows,MCols> MatrixType;
   static void run(MatrixType& mat, SluMatrix& res)
   {
-    assert(StorageOrder==0 && "row-major dense matrices is not supported by SuperLU");
+    ei_assert( ((Options&RowMajor)!=RowMajor) && "row-major dense matrices is not supported by SuperLU");
     res.setStorageType(SLU_DN);
     res.setScalarType<Scalar>();
     res.Mtype     = SLU_GE;
@@ -139,7 +139,7 @@
   typedef SparseMatrix<Scalar,Flags> MatrixType;
   static void run(MatrixType& mat, SluMatrix& res)
   {
-    if (Flags&RowMajorBit)
+    if ((Flags&RowMajorBit)==RowMajorBit)
     {
       res.setStorageType(SLU_NR);
       res.nrow      = mat.cols();
@@ -181,7 +181,7 @@
 SparseMatrix<Scalar,Flags> SparseMatrix<Scalar,Flags>::Map(SluMatrix& sluMat)
 {
   SparseMatrix res;
-  if (Flags&RowMajorBit)
+  if ((Flags&RowMajorBit)==RowMajorBit)
   {
     assert(sluMat.Stype == SLU_NR);
     res.m_innerSize   = sluMat.ncol;
@@ -276,7 +276,7 @@
     mutable UMatrixType m_u;
     mutable IntColVectorType m_p;
     mutable IntRowVectorType m_q;
-    
+
     mutable SparseMatrix<Scalar> m_matrix;
     mutable SluMatrix m_sluA;
     mutable SuperMatrix m_sluL, m_sluU;
@@ -423,7 +423,7 @@
     int* Ucol = m_u._outerIndexPtr();
     int* Urow = m_u._innerIndexPtr();
     Scalar* Uval = m_u._valuePtr();
-    
+
     Ucol[0] = 0;
     Ucol[0] = 0;
 
@@ -434,7 +434,7 @@
       istart  = L_SUB_START(fsupc);
       nsupr   = L_SUB_START(fsupc+1) - istart;
       upper   = 1;
-      
+
       /* for each column in the supernode */
       for (int j = fsupc; j < L_FST_SUPC(k+1); ++j)
       {
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 326965c..0fac209 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -187,5 +187,5 @@
 ei_add_test(alignedbox)
 ei_add_test(regression)
 ei_add_test(sparse_basic " " "${SPARSE_LIBS}")
+ei_add_test(sparse_vector " " "${SPARSE_LIBS}")
 ei_add_test(sparse_solvers " " "${SPARSE_LIBS}")
-
diff --git a/test/sparse.h b/test/sparse.h
index bf4a2ac..310e976 100644
--- a/test/sparse.h
+++ b/test/sparse.h
@@ -89,4 +89,28 @@
   sparseMat.endFill();
 }
 
+template<typename Scalar> void
+initSparse(double density,
+           Matrix<Scalar,Dynamic,1>& refVec,
+           SparseVector<Scalar>& sparseVec,
+           std::vector<int>* zeroCoords = 0,
+           std::vector<int>* nonzeroCoords = 0)
+{
+  sparseVec.reserve(refVec.size()*density);
+  sparseVec.setZero();
+  for(int i=0; i<refVec.size(); i++)
+  {
+    Scalar v = (ei_random<double>(0,1) < density) ? ei_random<Scalar>() : Scalar(0);
+    if (v!=Scalar(0))
+    {
+      sparseVec.fill(i) = v;
+      if (nonzeroCoords)
+        nonzeroCoords->push_back(i);
+    }
+    else if (zeroCoords)
+        zeroCoords->push_back(i);
+    refVec[i] = v;
+  }
+}
+
 #endif // EIGEN_TESTSPARSE_H
diff --git a/test/sparse_vector.cpp b/test/sparse_vector.cpp
new file mode 100644
index 0000000..0a25884
--- /dev/null
+++ b/test/sparse_vector.cpp
@@ -0,0 +1,92 @@
+// This file is part of Eigen, a lightweight C++ template library
+// for linear algebra. Eigen itself is part of the KDE project.
+//
+// Copyright (C) 2008 Daniel Gomez Ferro <dgomezferro@gmail.com>
+//
+// Eigen is free software; you can redistribute it and/or
+// modify it under the terms of the GNU Lesser General Public
+// License as published by the Free Software Foundation; either
+// version 3 of the License, or (at your option) any later version.
+//
+// Alternatively, you can redistribute it and/or
+// modify it under the terms of the GNU General Public License as
+// published by the Free Software Foundation; either version 2 of
+// the License, or (at your option) any later version.
+//
+// Eigen is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+// FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License or the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License and a copy of the GNU General Public License along with
+// Eigen. If not, see <http://www.gnu.org/licenses/>.
+
+#include "sparse.h"
+
+template<typename Scalar> void sparse_vector(int rows, int cols)
+{
+  double densityMat = std::max(8./(rows*cols), 0.01);
+  double densityVec = std::max(8./float(rows), 0.1);
+  typedef Matrix<Scalar,Dynamic,Dynamic> DenseMatrix;
+  typedef Matrix<Scalar,Dynamic,1> DenseVector;
+  typedef SparseVector<Scalar> SparseVectorType;
+  typedef SparseMatrix<Scalar> SparseMatrixType;
+  Scalar eps = 1e-6;
+
+  SparseMatrixType m1(rows,cols);
+  SparseVectorType v1(rows), v2(rows), v3(rows);
+  DenseMatrix refM1 = DenseMatrix::Zero(rows, cols);
+  DenseVector refV1 = DenseVector::Random(rows),
+    refV2 = DenseVector::Random(rows),
+    refV3 = DenseVector::Random(rows);
+
+  std::vector<int> zerocoords, nonzerocoords;
+  initSparse<Scalar>(densityVec, refV1, v1, &zerocoords, &nonzerocoords);
+  initSparse<Scalar>(densityMat, refM1, m1);
+
+  initSparse<Scalar>(densityVec, refV2, v2);
+  initSparse<Scalar>(densityVec, refV3, v3);
+
+  Scalar s1 = ei_random<Scalar>();
+
+  // test coeff and coeffRef
+  for (unsigned int i=0; i<zerocoords.size(); ++i)
+  {
+    VERIFY_IS_MUCH_SMALLER_THAN( v1.coeff(zerocoords[i]), eps );
+    VERIFY_RAISES_ASSERT( v1.coeffRef(zerocoords[i]) = 5 );
+  }
+  {
+    VERIFY(int(nonzerocoords.size()) == v1.nonZeros());
+    int j=0;
+    for (typename SparseVectorType::InnerIterator it(v1); it; ++it,++j)
+    {
+      VERIFY(nonzerocoords[j]==it.index());
+      VERIFY(it.value()==v1[it.index()]);
+    }
+  }
+  VERIFY_IS_APPROX(v1, refV1);
+
+  v1.coeffRef(nonzerocoords[0]) = Scalar(5);
+  refV1.coeffRef(nonzerocoords[0]) = Scalar(5);
+  VERIFY_IS_APPROX(v1, refV1);
+
+  VERIFY_IS_APPROX(v1+v2, refV1+refV2);
+  VERIFY_IS_APPROX(v1+v2+v3, refV1+refV2+refV3);
+
+  VERIFY_IS_APPROX(v1*s1-v2, refV1*s1-refV2);
+
+  std::cerr << v1.dot(v2) << " == " << refV1.dot(refV2) << "\n";
+  VERIFY_IS_APPROX(v1.dot(v2), refV1.dot(refV2));
+
+}
+
+void test_sparse_vector()
+{
+  for(int i = 0; i < g_repeat; i++) {
+    CALL_SUBTEST( sparse_vector<double>(8, 8) );
+//     CALL_SUBTEST( sparse_vector<std::complex<double> >(16, 16) );
+    CALL_SUBTEST( sparse_vector<double>(299, 535) );
+  }
+}
+