Merge of itasc branch. Project files, scons and cmake should be working. Makefile updated but not tested. Comes with Eigen2 2.0.6 C++ matrix library.

30 files changed, 7415 insertions, 0 deletions

diff --git a/extern/Eigen2/Eigen/src/Sparse/AmbiVector.h b/extern/Eigen2/Eigen/src/Sparse/AmbiVector.h
new file mode 100644
index 00000000000..75001a2fa25
--- /dev/null
+++ b/extern/Eigen2/Eigen/src/Sparse/AmbiVector.h
@@ -0,0 +1,371 @@
+// 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_AMBIVECTOR_H
+#define EIGEN_AMBIVECTOR_H
+
+/** \internal
+  * Hybrid sparse/dense vector class designed for intensive read-write operations.
+  *
+  * See BasicSparseLLT and SparseProduct for usage examples.
+  */
+template<typename _Scalar> class AmbiVector
+{
+  public:
+    typedef _Scalar Scalar;
+    typedef typename NumTraits<Scalar>::Real RealScalar;
+    AmbiVector(int size)
+      : m_buffer(0), m_size(0), m_allocatedSize(0), m_allocatedElements(0), m_mode(-1)
+    {
+      resize(size);
+    }
+
+    void init(RealScalar estimatedDensity);
+    void init(int mode);
+
+    void nonZeros() const;
+
+    /** Specifies a sub-vector to work on */
+    void setBounds(int start, int end) { m_start = start; m_end = end; }
+
+    void setZero();
+
+    void restart();
+    Scalar& coeffRef(int i);
+    Scalar coeff(int i);
+
+    class Iterator;
+
+    ~AmbiVector() { delete[] m_buffer; }
+
+    void resize(int size)
+    {
+      if (m_allocatedSize < size)
+        reallocate(size);
+      m_size = size;
+    }
+
+    int size() const { return m_size; }
+
+  protected:
+
+    void reallocate(int size)
+    {
+      // if the size of the matrix is not too large, let's allocate a bit more than needed such
+      // that we can handle dense vector even in sparse mode.
+      delete[] m_buffer;
+      if (size<1000)
+      {
+        int allocSize = (size * sizeof(ListEl))/sizeof(Scalar);
+        m_allocatedElements = (allocSize*sizeof(Scalar))/sizeof(ListEl);
+        m_buffer = new Scalar[allocSize];
+      }
+      else
+      {
+        m_allocatedElements = (size*sizeof(Scalar))/sizeof(ListEl);
+        m_buffer = new Scalar[size];
+      }
+      m_size = size;
+      m_start = 0;
+      m_end = m_size;
+    }
+
+    void reallocateSparse()
+    {
+      int copyElements = m_allocatedElements;
+      m_allocatedElements = std::min(int(m_allocatedElements*1.5),m_size);
+      int allocSize = m_allocatedElements * sizeof(ListEl);
+      allocSize = allocSize/sizeof(Scalar) + (allocSize%sizeof(Scalar)>0?1:0);
+      Scalar* newBuffer = new Scalar[allocSize];
+      memcpy(newBuffer,  m_buffer,  copyElements * sizeof(ListEl));
+    }
+
+  protected:
+    // element type of the linked list
+    struct ListEl
+    {
+      int next;
+      int index;
+      Scalar value;
+    };
+
+    // used to store data in both mode
+    Scalar* m_buffer;
+    int m_size;
+    int m_start;
+    int m_end;
+    int m_allocatedSize;
+    int m_allocatedElements;
+    int m_mode;
+
+    // linked list mode
+    int m_llStart;
+    int m_llCurrent;
+    int m_llSize;
+
+  private:
+    AmbiVector(const AmbiVector&);
+
+};
+
+/** \returns the number of non zeros in the current sub vector */
+template<typename Scalar>
+void AmbiVector<Scalar>::nonZeros() const
+{
+  if (m_mode==IsSparse)
+    return m_llSize;
+  else
+    return m_end - m_start;
+}
+
+template<typename Scalar>
+void AmbiVector<Scalar>::init(RealScalar estimatedDensity)
+{
+  if (estimatedDensity>0.1)
+    init(IsDense);
+  else
+    init(IsSparse);
+}
+
+template<typename Scalar>
+void AmbiVector<Scalar>::init(int mode)
+{
+  m_mode = mode;
+  if (m_mode==IsSparse)
+  {
+    m_llSize = 0;
+    m_llStart = -1;
+  }
+}
+
+/** Must be called whenever we might perform a write access
+  * with an index smaller than the previous one.
+  *
+  * Don't worry, this function is extremely cheap.
+  */
+template<typename Scalar>
+void AmbiVector<Scalar>::restart()
+{
+  m_llCurrent = m_llStart;
+}
+
+/** Set all coefficients of current subvector to zero */
+template<typename Scalar>
+void AmbiVector<Scalar>::setZero()
+{
+  if (m_mode==IsDense)
+  {
+    for (int i=m_start; i<m_end; ++i)
+      m_buffer[i] = Scalar(0);
+  }
+  else
+  {
+    ei_assert(m_mode==IsSparse);
+    m_llSize = 0;
+    m_llStart = -1;
+  }
+}
+
+template<typename Scalar>
+Scalar& AmbiVector<Scalar>::coeffRef(int i)
+{
+  if (m_mode==IsDense)
+    return m_buffer[i];
+  else
+  {
+    ListEl* EIGEN_RESTRICT llElements = reinterpret_cast<ListEl*>(m_buffer);
+    // TODO factorize the following code to reduce code generation
+    ei_assert(m_mode==IsSparse);
+    if (m_llSize==0)
+    {
+      // this is the first element
+      m_llStart = 0;
+      m_llCurrent = 0;
+      ++m_llSize;
+      llElements[0].value = Scalar(0);
+      llElements[0].index = i;
+      llElements[0].next = -1;
+      return llElements[0].value;
+    }
+    else if (i<llElements[m_llStart].index)
+    {
+      // this is going to be the new first element of the list
+      ListEl& el = llElements[m_llSize];
+      el.value = Scalar(0);
+      el.index = i;
+      el.next = m_llStart;
+      m_llStart = m_llSize;
+      ++m_llSize;
+      m_llCurrent = m_llStart;
+      return el.value;
+    }
+    else
+    {
+      int nextel = llElements[m_llCurrent].next;
+      ei_assert(i>=llElements[m_llCurrent].index && "you must call restart() before inserting an element with lower or equal index");
+      while (nextel >= 0 && llElements[nextel].index<=i)
+      {
+        m_llCurrent = nextel;
+        nextel = llElements[nextel].next;
+      }
+
+      if (llElements[m_llCurrent].index==i)
+      {
+        // the coefficient already exists and we found it !
+        return llElements[m_llCurrent].value;
+      }
+      else
+      {
+        if (m_llSize>=m_allocatedElements)
+          reallocateSparse();
+        ei_internal_assert(m_llSize<m_size && "internal error: overflow in sparse mode");
+        // let's insert a new coefficient
+        ListEl& el = llElements[m_llSize];
+        el.value = Scalar(0);
+        el.index = i;
+        el.next = llElements[m_llCurrent].next;
+        llElements[m_llCurrent].next = m_llSize;
+        ++m_llSize;
+        return el.value;
+      }
+    }
+  }
+}
+
+template<typename Scalar>
+Scalar AmbiVector<Scalar>::coeff(int i)
+{
+  if (m_mode==IsDense)
+    return m_buffer[i];
+  else
+  {
+    ListEl* EIGEN_RESTRICT llElements = reinterpret_cast<ListEl*>(m_buffer);
+    ei_assert(m_mode==IsSparse);
+    if ((m_llSize==0) || (i<llElements[m_llStart].index))
+    {
+      return Scalar(0);
+    }
+    else
+    {
+      int elid = m_llStart;
+      while (elid >= 0 && llElements[elid].index<i)
+        elid = llElements[elid].next;
+
+      if (llElements[elid].index==i)
+        return llElements[m_llCurrent].value;
+      else
+        return Scalar(0);
+    }
+  }
+}
+
+/** Iterator over the nonzero coefficients */
+template<typename _Scalar>
+class AmbiVector<_Scalar>::Iterator
+{
+  public:
+    typedef _Scalar Scalar;
+    typedef typename NumTraits<Scalar>::Real RealScalar;
+
+    /** Default constructor
+      * \param vec the vector on which we iterate
+      * \param epsilon the minimal value used to prune zero coefficients.
+      * In practice, all coefficients having a magnitude smaller than \a epsilon
+      * are skipped.
+      */
+    Iterator(const AmbiVector& vec, RealScalar epsilon = RealScalar(0.1)*precision<RealScalar>())
+      : m_vector(vec)
+    {
+      m_epsilon = epsilon;
+      m_isDense = m_vector.m_mode==IsDense;
+      if (m_isDense)
+      {
+        m_cachedIndex = m_vector.m_start-1;
+        ++(*this);
+      }
+      else
+      {
+        ListEl* EIGEN_RESTRICT llElements = reinterpret_cast<ListEl*>(m_vector.m_buffer);
+        m_currentEl = m_vector.m_llStart;
+        while (m_currentEl>=0 && ei_abs(llElements[m_currentEl].value)<m_epsilon)
+          m_currentEl = llElements[m_currentEl].next;
+        if (m_currentEl<0)
+        {
+          m_cachedIndex = -1;
+        }
+        else
+        {
+          m_cachedIndex = llElements[m_currentEl].index;
+          m_cachedValue = llElements[m_currentEl].value;
+        }
+      }
+    }
+
+    int index() const { return m_cachedIndex; }
+    Scalar value() const { return m_cachedValue; }
+
+    operator bool() const { return m_cachedIndex>=0; }
+
+    Iterator& operator++()
+    {
+      if (m_isDense)
+      {
+        do {
+          ++m_cachedIndex;
+        } while (m_cachedIndex<m_vector.m_end && ei_abs(m_vector.m_buffer[m_cachedIndex])<m_epsilon);
+        if (m_cachedIndex<m_vector.m_end)
+          m_cachedValue = m_vector.m_buffer[m_cachedIndex];
+        else
+          m_cachedIndex=-1;
+      }
+      else
+      {
+        ListEl* EIGEN_RESTRICT llElements = reinterpret_cast<ListEl*>(m_vector.m_buffer);
+        do {
+          m_currentEl = llElements[m_currentEl].next;
+        } while (m_currentEl>=0 && ei_abs(llElements[m_currentEl].value)<m_epsilon);
+        if (m_currentEl<0)
+        {
+          m_cachedIndex = -1;
+        }
+        else
+        {
+          m_cachedIndex = llElements[m_currentEl].index;
+          m_cachedValue = llElements[m_currentEl].value;
+        }
+      }
+      return *this;
+    }
+
+  protected:
+    const AmbiVector& m_vector; // the target vector
+    int m_currentEl;            // the current element in sparse/linked-list mode
+    RealScalar m_epsilon;       // epsilon used to prune zero coefficients
+    int m_cachedIndex;          // current coordinate
+    Scalar m_cachedValue;       // current value
+    bool m_isDense;             // mode of the vector
+};
+
+
+#endif // EIGEN_AMBIVECTOR_H
diff --git a/extern/Eigen2/Eigen/src/Sparse/CholmodSupport.h b/extern/Eigen2/Eigen/src/Sparse/CholmodSupport.h
new file mode 100644
index 00000000000..dfd9c787ae9
--- /dev/null
+++ b/extern/Eigen2/Eigen/src/Sparse/CholmodSupport.h
@@ -0,0 +1,236 @@
+// This file is part of Eigen, a lightweight C++ template library
+// for linear algebra. Eigen itself is part of the KDE project.
+//
+// Copyright (C) 2008-2009 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_CHOLMODSUPPORT_H
+#define EIGEN_CHOLMODSUPPORT_H
+
+template<typename Scalar, typename CholmodType>
+void ei_cholmod_configure_matrix(CholmodType& mat)
+{
+  if (ei_is_same_type<Scalar,float>::ret)
+  {
+    mat.xtype = CHOLMOD_REAL;
+    mat.dtype = 1;
+  }
+  else if (ei_is_same_type<Scalar,double>::ret)
+  {
+    mat.xtype = CHOLMOD_REAL;
+    mat.dtype = 0;
+  }
+  else if (ei_is_same_type<Scalar,std::complex<float> >::ret)
+  {
+    mat.xtype = CHOLMOD_COMPLEX;
+    mat.dtype = 1;
+  }
+  else if (ei_is_same_type<Scalar,std::complex<double> >::ret)
+  {
+    mat.xtype = CHOLMOD_COMPLEX;
+    mat.dtype = 0;
+  }
+  else
+  {
+    ei_assert(false && "Scalar type not supported by CHOLMOD");
+  }
+}
+
+template<typename Derived>
+cholmod_sparse SparseMatrixBase<Derived>::asCholmodMatrix()
+{
+  typedef typename Derived::Scalar Scalar;
+  cholmod_sparse res;
+  res.nzmax   = nonZeros();
+  res.nrow    = rows();;
+  res.ncol    = cols();
+  res.p       = derived()._outerIndexPtr();
+  res.i       = derived()._innerIndexPtr();
+  res.x       = derived()._valuePtr();
+  res.xtype = CHOLMOD_REAL;
+  res.itype = CHOLMOD_INT;
+  res.sorted = 1;
+  res.packed = 1;
+  res.dtype = 0;
+  res.stype = -1;
+
+  ei_cholmod_configure_matrix<Scalar>(res);
+
+  if (Derived::Flags & SelfAdjoint)
+  {
+    if (Derived::Flags & UpperTriangular)
+      res.stype = 1;
+    else if (Derived::Flags & LowerTriangular)
+      res.stype = -1;
+    else
+      res.stype = 0;
+  }
+  else
+    res.stype = 0;
+
+  return res;
+}
+
+template<typename Derived>
+cholmod_dense ei_cholmod_map_eigen_to_dense(MatrixBase<Derived>& mat)
+{
+  EIGEN_STATIC_ASSERT((ei_traits<Derived>::Flags&RowMajorBit)==0,THIS_METHOD_IS_ONLY_FOR_COLUMN_MAJOR_MATRICES);
+  typedef typename Derived::Scalar Scalar;
+
+  cholmod_dense res;
+  res.nrow   = mat.rows();
+  res.ncol   = mat.cols();
+  res.nzmax  = res.nrow * res.ncol;
+  res.d      = mat.derived().stride();
+  res.x      = mat.derived().data();
+  res.z      = 0;
+
+  ei_cholmod_configure_matrix<Scalar>(res);
+
+  return res;
+}
+
+template<typename Scalar, int Flags>
+MappedSparseMatrix<Scalar,Flags>::MappedSparseMatrix(cholmod_sparse& cm)
+{
+  m_innerSize = cm.nrow;
+  m_outerSize = cm.ncol;
+  m_outerIndex = reinterpret_cast<int*>(cm.p);
+  m_innerIndices = reinterpret_cast<int*>(cm.i);
+  m_values = reinterpret_cast<Scalar*>(cm.x);
+  m_nnz = m_outerIndex[cm.ncol];
+}
+
+template<typename MatrixType>
+class SparseLLT<MatrixType,Cholmod> : public SparseLLT<MatrixType>
+{
+  protected:
+    typedef SparseLLT<MatrixType> Base;
+    typedef typename Base::Scalar Scalar;
+    typedef typename Base::RealScalar RealScalar;
+    using Base::MatrixLIsDirty;
+    using Base::SupernodalFactorIsDirty;
+    using Base::m_flags;
+    using Base::m_matrix;
+    using Base::m_status;
+
+  public:
+
+    SparseLLT(int flags = 0)
+      : Base(flags), m_cholmodFactor(0)
+    {
+      cholmod_start(&m_cholmod);
+    }
+
+    SparseLLT(const MatrixType& matrix, int flags = 0)
+      : Base(flags), m_cholmodFactor(0)
+    {
+      cholmod_start(&m_cholmod);
+      compute(matrix);
+    }
+
+    ~SparseLLT()
+    {
+      if (m_cholmodFactor)
+        cholmod_free_factor(&m_cholmodFactor, &m_cholmod);
+      cholmod_finish(&m_cholmod);
+    }
+
+    inline const typename Base::CholMatrixType& matrixL(void) const;
+
+    template<typename Derived>
+    void solveInPlace(MatrixBase<Derived> &b) const;
+
+    void compute(const MatrixType& matrix);
+
+  protected:
+    mutable cholmod_common m_cholmod;
+    cholmod_factor* m_cholmodFactor;
+};
+
+template<typename MatrixType>
+void SparseLLT<MatrixType,Cholmod>::compute(const MatrixType& a)
+{
+  if (m_cholmodFactor)
+  {
+    cholmod_free_factor(&m_cholmodFactor, &m_cholmod);
+    m_cholmodFactor = 0;
+  }
+
+  cholmod_sparse A = const_cast<MatrixType&>(a).asCholmodMatrix();
+  m_cholmod.supernodal = CHOLMOD_AUTO;
+  // TODO
+  if (m_flags&IncompleteFactorization)
+  {
+    m_cholmod.nmethods = 1;
+    m_cholmod.method[0].ordering = CHOLMOD_NATURAL;
+    m_cholmod.postorder = 0;
+  }
+  else
+  {
+    m_cholmod.nmethods = 1;
+    m_cholmod.method[0].ordering = CHOLMOD_NATURAL;
+    m_cholmod.postorder = 0;
+  }
+  m_cholmod.final_ll = 1;
+  m_cholmodFactor = cholmod_analyze(&A, &m_cholmod);
+  cholmod_factorize(&A, m_cholmodFactor, &m_cholmod);
+
+  m_status = (m_status & ~SupernodalFactorIsDirty) | MatrixLIsDirty;
+}
+
+template<typename MatrixType>
+inline const typename SparseLLT<MatrixType>::CholMatrixType&
+SparseLLT<MatrixType,Cholmod>::matrixL() const
+{
+  if (m_status & MatrixLIsDirty)
+  {
+    ei_assert(!(m_status & SupernodalFactorIsDirty));
+
+    cholmod_sparse* cmRes = cholmod_factor_to_sparse(m_cholmodFactor, &m_cholmod);
+    const_cast<typename Base::CholMatrixType&>(m_matrix) = MappedSparseMatrix<Scalar>(*cmRes);
+    free(cmRes);
+
+    m_status = (m_status & ~MatrixLIsDirty);
+  }
+  return m_matrix;
+}
+
+template<typename MatrixType>
+template<typename Derived>
+void SparseLLT<MatrixType,Cholmod>::solveInPlace(MatrixBase<Derived> &b) const
+{
+  const int size = m_cholmodFactor->n;
+  ei_assert(size==b.rows());
+
+  // this uses Eigen's triangular sparse solver
+//   if (m_status & MatrixLIsDirty)
+//     matrixL();
+//   Base::solveInPlace(b);
+  // as long as our own triangular sparse solver is not fully optimal,
+  // let's use CHOLMOD's one:
+  cholmod_dense cdb = ei_cholmod_map_eigen_to_dense(b);
+  cholmod_dense* x = cholmod_solve(CHOLMOD_LDLt, m_cholmodFactor, &cdb, &m_cholmod);
+  b = Matrix<typename Base::Scalar,Dynamic,1>::Map(reinterpret_cast<typename Base::Scalar*>(x->x),b.rows());
+  cholmod_free_dense(&x, &m_cholmod);
+}
+
+#endif // EIGEN_CHOLMODSUPPORT_H
diff --git a/extern/Eigen2/Eigen/src/Sparse/CompressedStorage.h b/extern/Eigen2/Eigen/src/Sparse/CompressedStorage.h
new file mode 100644
index 00000000000..4dbd3230985
--- /dev/null
+++ b/extern/Eigen2/Eigen/src/Sparse/CompressedStorage.h
@@ -0,0 +1,230 @@
+// 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_COMPRESSED_STORAGE_H
+#define EIGEN_COMPRESSED_STORAGE_H
+
+/** Stores a sparse set of values as a list of values and a list of indices.
+  *
+  */
+template<typename Scalar>
+class CompressedStorage
+{
+    typedef typename NumTraits<Scalar>::Real RealScalar;
+  public:
+    CompressedStorage()
+      : m_values(0), m_indices(0), m_size(0), m_allocatedSize(0)
+    {}
+
+    CompressedStorage(size_t size)
+      : m_values(0), m_indices(0), m_size(0), m_allocatedSize(0)
+    {
+      resize(size);
+    }
+
+    CompressedStorage(const CompressedStorage& other)
+      : m_values(0), m_indices(0), m_size(0), m_allocatedSize(0)
+    {
+      *this = other;
+    }
+
+    CompressedStorage& operator=(const CompressedStorage& other)
+    {
+      resize(other.size());
+      memcpy(m_values, other.m_values, m_size * sizeof(Scalar));
+      memcpy(m_indices, other.m_indices, m_size * sizeof(int));
+      return *this;
+    }
+
+    void swap(CompressedStorage& other)
+    {
+      std::swap(m_values, other.m_values);
+      std::swap(m_indices, other.m_indices);
+      std::swap(m_size, other.m_size);
+      std::swap(m_allocatedSize, other.m_allocatedSize);
+    }
+
+    ~CompressedStorage()
+    {
+      delete[] m_values;
+      delete[] m_indices;
+    }
+
+    void reserve(size_t size)
+    {
+      size_t newAllocatedSize = m_size + size;
+      if (newAllocatedSize > m_allocatedSize)
+        reallocate(newAllocatedSize);
+    }
+
+    void squeeze()
+    {
+      if (m_allocatedSize>m_size)
+        reallocate(m_size);
+    }
+
+    void resize(size_t size, float reserveSizeFactor = 0)
+    {
+      if (m_allocatedSize<size)
+        reallocate(size + size_t(reserveSizeFactor*size));
+      m_size = size;
+    }
+
+    void append(const Scalar& v, int i)
+    {
+      int id = m_size;
+      resize(m_size+1, 1);
+      m_values[id] = v;
+      m_indices[id] = i;
+    }
+
+    inline size_t size() const { return m_size; }
+    inline size_t allocatedSize() const { return m_allocatedSize; }
+    inline void clear() { m_size = 0; }
+
+    inline Scalar& value(size_t i) { return m_values[i]; }
+    inline const Scalar& value(size_t i) const { return m_values[i]; }
+
+    inline int& index(size_t i) { return m_indices[i]; }
+    inline const int& index(size_t i) const { return m_indices[i]; }
+
+    static CompressedStorage Map(int* indices, Scalar* values, size_t size)
+    {
+      CompressedStorage res;
+      res.m_indices = indices;
+      res.m_values = values;
+      res.m_allocatedSize = res.m_size = size;
+      return res;
+    }
+    
+    /** \returns the largest \c k such that for all \c j in [0,k) index[\c j]\<\a key */
+    inline int searchLowerIndex(int key) const
+    {
+      return searchLowerIndex(0, m_size, key);
+    }
+    
+    /** \returns the largest \c k in [start,end) such that for all \c j in [start,k) index[\c j]\<\a key */
+    inline int searchLowerIndex(size_t start, size_t end, int key) const
+    {
+      while(end>start)
+      {
+        size_t mid = (end+start)>>1;
+        if (m_indices[mid]<key)
+          start = mid+1;
+        else
+          end = mid;
+      }
+      return start;
+    }
+    
+    /** \returns the stored value at index \a key
+      * If the value does not exist, then the value \a defaultValue is returned without any insertion. */
+    inline Scalar at(int key, Scalar defaultValue = Scalar(0)) const
+    {
+      if (m_size==0)
+        return defaultValue;
+      else if (key==m_indices[m_size-1])
+        return m_values[m_size-1];
+      // ^^  optimization: let's first check if it is the last coefficient
+      // (very common in high level algorithms)
+      const size_t id = searchLowerIndex(0,m_size-1,key);
+      return ((id<m_size) && (m_indices[id]==key)) ? m_values[id] : defaultValue;
+    }
+    
+    /** Like at(), but the search is performed in the range [start,end) */
+    inline Scalar atInRange(size_t start, size_t end, int key, Scalar defaultValue = Scalar(0)) const
+    {
+      if (start==end)
+        return Scalar(0);
+      else if (end>start && key==m_indices[end-1])
+        return m_values[end-1];
+      // ^^  optimization: let's first check if it is the last coefficient
+      // (very common in high level algorithms)
+      const size_t id = searchLowerIndex(start,end-1,key);
+      return ((id<end) && (m_indices[id]==key)) ? m_values[id] : defaultValue;
+    }
+    
+    /** \returns a reference to the value at index \a key
+      * If the value does not exist, then the value \a defaultValue is inserted
+      * such that the keys are sorted. */
+    inline Scalar& atWithInsertion(int key, Scalar defaultValue = Scalar(0))
+    {
+      size_t id = searchLowerIndex(0,m_size,key);
+      if (id>=m_size || m_indices[id]!=key)
+      {
+        resize(m_size+1,1);
+        for (size_t j=m_size-1; j>id; --j)
+        {
+          m_indices[j] = m_indices[j-1];
+          m_values[j] = m_values[j-1];
+        }
+        m_indices[id] = key;
+        m_values[id] = defaultValue;
+      }
+      return m_values[id];
+    }
+    
+    void prune(Scalar reference, RealScalar epsilon = precision<RealScalar>())
+    {
+      size_t k = 0;
+      size_t n = size();
+      for (size_t i=0; i<n; ++i)
+      {
+        if (!ei_isMuchSmallerThan(value(i), reference, epsilon))
+        {
+          value(k) = value(i);
+          index(k) = index(i);
+          ++k;
+        }
+      }
+      resize(k,0);
+    }
+
+  protected:
+
+    inline void reallocate(size_t size)
+    {
+      Scalar* newValues  = new Scalar[size];
+      int* newIndices = new int[size];
+      size_t copySize = std::min(size, m_size);
+      // copy
+      memcpy(newValues,  m_values,  copySize * sizeof(Scalar));
+      memcpy(newIndices, m_indices, copySize * sizeof(int));
+      // delete old stuff
+      delete[] m_values;
+      delete[] m_indices;
+      m_values = newValues;
+      m_indices = newIndices;
+      m_allocatedSize = size;
+    }
+
+  protected:
+    Scalar* m_values;
+    int* m_indices;
+    size_t m_size;
+    size_t m_allocatedSize;
+
+};
+
+#endif // EIGEN_COMPRESSED_STORAGE_H
diff --git a/extern/Eigen2/Eigen/src/Sparse/CoreIterators.h b/extern/Eigen2/Eigen/src/Sparse/CoreIterators.h
new file mode 100644
index 00000000000..f1520a585ca
--- /dev/null
+++ b/extern/Eigen2/Eigen/src/Sparse/CoreIterators.h
@@ -0,0 +1,68 @@
+// 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_COREITERATORS_H
+#define EIGEN_COREITERATORS_H
+
+/* This file contains the respective InnerIterator definition of the expressions defined in Eigen/Core
+ */
+
+/** \class InnerIterator
+  * \brief An InnerIterator allows to loop over the element of a sparse (or dense) matrix or expression
+  *
+  * todo
+  */
+
+// generic version for dense matrix and expressions
+template<typename Derived> class MatrixBase<Derived>::InnerIterator
+{
+    typedef typename Derived::Scalar Scalar;
+    enum { IsRowMajor = (Derived::Flags&RowMajorBit)==RowMajorBit };
+  public:
+    EIGEN_STRONG_INLINE InnerIterator(const Derived& expr, int outer)
+      : m_expression(expr), m_inner(0), m_outer(outer), m_end(expr.rows())
+    {}
+
+    EIGEN_STRONG_INLINE Scalar value() const
+    {
+      return (IsRowMajor) ? m_expression.coeff(m_outer, m_inner)
+                          : m_expression.coeff(m_inner, m_outer);
+    }
+
+    EIGEN_STRONG_INLINE InnerIterator& operator++() { m_inner++; return *this; }
+
+    EIGEN_STRONG_INLINE int index() const { return m_inner; }
+    inline int row() const { return IsRowMajor ? m_outer : index(); }
+    inline int col() const { return IsRowMajor ? index() : m_outer; }
+
+    EIGEN_STRONG_INLINE operator bool() const { return m_inner < m_end && m_inner>=0; }
+
+  protected:
+    const Derived& m_expression;
+    int m_inner;
+    const int m_outer;
+    const int m_end;
+};
+
+#endif // EIGEN_COREITERATORS_H
diff --git a/extern/Eigen2/Eigen/src/Sparse/DynamicSparseMatrix.h b/extern/Eigen2/Eigen/src/Sparse/DynamicSparseMatrix.h
new file mode 100644
index 00000000000..7119a84bd51
--- /dev/null
+++ b/extern/Eigen2/Eigen/src/Sparse/DynamicSparseMatrix.h
@@ -0,0 +1,297 @@
+// This file is part of Eigen, a lightweight C++ template library
+// for linear algebra. Eigen itself is part of the KDE project.
+//
+// Copyright (C) 2008-2009 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_DYNAMIC_SPARSEMATRIX_H
+#define EIGEN_DYNAMIC_SPARSEMATRIX_H
+
+/** \class DynamicSparseMatrix
+  *
+  * \brief A sparse matrix class designed for matrix assembly purpose
+  *
+  * \param _Scalar the scalar type, i.e. the type of the coefficients
+  *
+  * Unlike SparseMatrix, this class provides a much higher degree of flexibility. In particular, it allows
+  * random read/write accesses in log(rho*outer_size) where \c rho is the probability that a coefficient is
+  * nonzero and outer_size is the number of columns if the matrix is column-major and the number of rows
+  * otherwise.
+  * 
+  * Internally, the data are stored as a std::vector of compressed vector. The performances of random writes might
+  * decrease as the number of nonzeros per inner-vector increase. In practice, we observed very good performance
+  * till about 100 nonzeros/vector, and the performance remains relatively good till 500 nonzeros/vectors.
+  *
+  * \see SparseMatrix
+  */
+template<typename _Scalar, int _Flags>
+struct ei_traits<DynamicSparseMatrix<_Scalar, _Flags> >
+{
+  typedef _Scalar Scalar;
+  enum {
+    RowsAtCompileTime = Dynamic,
+    ColsAtCompileTime = Dynamic,
+    MaxRowsAtCompileTime = Dynamic,
+    MaxColsAtCompileTime = Dynamic,
+    Flags = SparseBit | _Flags,
+    CoeffReadCost = NumTraits<Scalar>::ReadCost,
+    SupportedAccessPatterns = OuterRandomAccessPattern
+  };
+};
+
+template<typename _Scalar, int _Flags>
+class DynamicSparseMatrix
+  : public SparseMatrixBase<DynamicSparseMatrix<_Scalar, _Flags> >
+{
+  public:
+    EIGEN_SPARSE_GENERIC_PUBLIC_INTERFACE(DynamicSparseMatrix)
+    // FIXME: why are these operator already alvailable ???
+    // EIGEN_SPARSE_INHERIT_ASSIGNMENT_OPERATOR(DynamicSparseMatrix, +=)
+    // EIGEN_SPARSE_INHERIT_ASSIGNMENT_OPERATOR(DynamicSparseMatrix, -=)
+    typedef MappedSparseMatrix<Scalar,Flags> Map;
+
+  protected:
+
+    enum { IsRowMajor = Base::IsRowMajor };
+    typedef DynamicSparseMatrix<Scalar,(Flags&~RowMajorBit)|(IsRowMajor?RowMajorBit:0)> TransposedSparseMatrix;
+
+    int m_innerSize;
+    std::vector<CompressedStorage<Scalar> > m_data;
+
+  public:
+  
+    inline int rows() const { return IsRowMajor ? outerSize() : m_innerSize; }
+    inline int cols() const { return IsRowMajor ? m_innerSize : outerSize(); }
+    inline int innerSize() const { return m_innerSize; }
+    inline int outerSize() const { return m_data.size(); }
+    inline int innerNonZeros(int j) const { return m_data[j].size(); }
+    
+    std::vector<CompressedStorage<Scalar> >& _data() { return m_data; }
+    const std::vector<CompressedStorage<Scalar> >& _data() const { return m_data; }
+
+    /** \returns the coefficient value at given position \a row, \a col
+      * This operation involes a log(rho*outer_size) binary search.
+      */
+    inline Scalar coeff(int row, int col) const
+    {
+      const int outer = IsRowMajor ? row : col;
+      const int inner = IsRowMajor ? col : row;
+      return m_data[outer].at(inner);
+    }
+
+    /** \returns a reference to the coefficient value at given position \a row, \a col
+      * This operation involes a log(rho*outer_size) binary search. If the coefficient does not
+      * exist yet, then a sorted insertion into a sequential buffer is performed.
+      */
+    inline Scalar& coeffRef(int row, int col)
+    {
+      const int outer = IsRowMajor ? row : col;
+      const int inner = IsRowMajor ? col : row;
+      return m_data[outer].atWithInsertion(inner);
+    }
+
+    class InnerIterator;
+
+    inline void setZero()
+    {
+      for (int j=0; j<outerSize(); ++j)
+        m_data[j].clear();
+    }
+
+    /** \returns the number of non zero coefficients */
+    inline int nonZeros() const
+    {
+      int res = 0;
+      for (int j=0; j<outerSize(); ++j)
+        res += m_data[j].size();
+      return res;
+    }
+
+    /** Set the matrix to zero and reserve the memory for \a reserveSize nonzero coefficients. */
+    inline void startFill(int reserveSize = 1000)
+    {
+      if (outerSize()>0)
+      {
+        int reserveSizePerVector = std::max(reserveSize/outerSize(),4);
+        for (int j=0; j<outerSize(); ++j)
+        {
+          m_data[j].clear();
+          m_data[j].reserve(reserveSizePerVector);
+        }
+      }
+    }
+
+    /** inserts a nonzero coefficient at given coordinates \a row, \a col and returns its reference assuming that:
+      *  1 - the coefficient does not exist yet
+      *  2 - this the coefficient with greater inner coordinate for the given outer coordinate.
+      * In other words, assuming \c *this is column-major, then there must not exists any nonzero coefficient of coordinates
+      * \c i \c x \a col such that \c i >= \a row. Otherwise the matrix is invalid.
+      * 
+      * \see fillrand(), coeffRef()
+      */
+    inline Scalar& fill(int row, int col)
+    {
+      const int outer = IsRowMajor ? row : col;
+      const int inner = IsRowMajor ? col : row;
+      ei_assert(outer<int(m_data.size()) && inner<m_innerSize);
+      ei_assert((m_data[outer].size()==0) || (m_data[outer].index(m_data[outer].size()-1)<inner));
+      m_data[outer].append(0, inner);
+      return m_data[outer].value(m_data[outer].size()-1);
+    }
+
+    /** Like fill() but with random inner coordinates.
+      * Compared to the generic coeffRef(), the unique limitation is that we assume
+      * the coefficient does not exist yet.
+      */
+    inline Scalar& fillrand(int row, int col)
+    {
+      const int outer = IsRowMajor ? row : col;
+      const int inner = IsRowMajor ? col : row;
+      
+      int startId = 0;
+      int id = m_data[outer].size() - 1;
+      m_data[outer].resize(id+2,1);
+
+      while ( (id >= startId) && (m_data[outer].index(id) > inner) )
+      {
+        m_data[outer].index(id+1) = m_data[outer].index(id);
+        m_data[outer].value(id+1) = m_data[outer].value(id);
+        --id;
+      }
+      m_data[outer].index(id+1) = inner;
+      m_data[outer].value(id+1) = 0;
+      return m_data[outer].value(id+1);
+    }
+
+    /** Does nothing. Provided for compatibility with SparseMatrix. */
+    inline void endFill() {}
+    
+    void prune(Scalar reference, RealScalar epsilon = precision<RealScalar>())
+    {
+      for (int j=0; j<outerSize(); ++j)
+        m_data[j].prune(reference,epsilon);
+    }
+
+    /** Resize the matrix without preserving the data (the matrix is set to zero)
+      */
+    void resize(int rows, int cols)
+    {
+      const int outerSize = IsRowMajor ? rows : cols;
+      m_innerSize = IsRowMajor ? cols : rows;
+      setZero();
+      if (int(m_data.size()) != outerSize)
+      {
+        m_data.resize(outerSize);
+      }
+    }
+    
+    void resizeAndKeepData(int rows, int cols)
+    {
+      const int outerSize = IsRowMajor ? rows : cols;
+      const int innerSize = IsRowMajor ? cols : rows;
+      if (m_innerSize>innerSize)
+      {
+        // remove all coefficients with innerCoord>=innerSize
+        // TODO
+        std::cerr << "not implemented yet\n";
+        exit(2);
+      }
+      if (m_data.size() != outerSize)
+      {
+        m_data.resize(outerSize);
+      }
+    }
+
+    inline DynamicSparseMatrix()
+      : m_innerSize(0), m_data(0)
+    {
+      ei_assert(innerSize()==0 && outerSize()==0);
+    }
+
+    inline DynamicSparseMatrix(int rows, int cols)
+      : m_innerSize(0)
+    {
+      resize(rows, cols);
+    }
+
+    template<typename OtherDerived>
+    inline DynamicSparseMatrix(const SparseMatrixBase<OtherDerived>& other)
+      : m_innerSize(0)
+    {
+      *this = other.derived();
+    }
+
+    inline DynamicSparseMatrix(const DynamicSparseMatrix& other)
+      : Base(), m_innerSize(0)
+    {
+      *this = other.derived();
+    }
+
+    inline void swap(DynamicSparseMatrix& other)
+    {
+      //EIGEN_DBG_SPARSE(std::cout << "SparseMatrix:: swap\n");
+      std::swap(m_innerSize, other.m_innerSize);
+      //std::swap(m_outerSize, other.m_outerSize);
+      m_data.swap(other.m_data);
+    }
+
+    inline DynamicSparseMatrix& operator=(const DynamicSparseMatrix& other)
+    {
+      if (other.isRValue())
+      {
+        swap(other.const_cast_derived());
+      }
+      else
+      {
+        resize(other.rows(), other.cols());
+        m_data = other.m_data;
+      }
+      return *this;
+    }
+
+    template<typename OtherDerived>
+    inline DynamicSparseMatrix& operator=(const SparseMatrixBase<OtherDerived>& other)
+    {
+      return SparseMatrixBase<DynamicSparseMatrix>::operator=(other.derived());
+    }
+
+    /** Destructor */
+    inline ~DynamicSparseMatrix() {}
+};
+
+template<typename Scalar, int _Flags>
+class DynamicSparseMatrix<Scalar,_Flags>::InnerIterator : public SparseVector<Scalar,_Flags>::InnerIterator
+{
+    typedef typename SparseVector<Scalar,_Flags>::InnerIterator Base;
+  public:
+    InnerIterator(const DynamicSparseMatrix& mat, int outer)
+      : Base(mat.m_data[outer]), m_outer(outer)
+    {}
+    
+    inline int row() const { return IsRowMajor ? m_outer : Base::index(); }
+    inline int col() const { return IsRowMajor ? Base::index() : m_outer; }
+
+
+  protected:
+    const int m_outer;
+};
+
+#endif // EIGEN_DYNAMIC_SPARSEMATRIX_H
diff --git a/extern/Eigen2/Eigen/src/Sparse/MappedSparseMatrix.h b/extern/Eigen2/Eigen/src/Sparse/MappedSparseMatrix.h
new file mode 100644
index 00000000000..f4935d8344e
--- /dev/null
+++ b/extern/Eigen2/Eigen/src/Sparse/MappedSparseMatrix.h
@@ -0,0 +1,175 @@
+// 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_MAPPED_SPARSEMATRIX_H
+#define EIGEN_MAPPED_SPARSEMATRIX_H
+
+/** \class MappedSparseMatrix
+  *
+  * \brief Sparse matrix
+  *
+  * \param _Scalar the scalar type, i.e. the type of the coefficients
+  *
+  * See http://www.netlib.org/linalg/html_templates/node91.html for details on the storage scheme.
+  *
+  */
+template<typename _Scalar, int _Flags>
+struct ei_traits<MappedSparseMatrix<_Scalar, _Flags> > : ei_traits<SparseMatrix<_Scalar, _Flags> >
+{};
+
+template<typename _Scalar, int _Flags>
+class MappedSparseMatrix
+  : public SparseMatrixBase<MappedSparseMatrix<_Scalar, _Flags> >
+{
+  public:
+    EIGEN_SPARSE_GENERIC_PUBLIC_INTERFACE(MappedSparseMatrix)
+
+  protected:
+    enum { IsRowMajor = Base::IsRowMajor };
+
+    int m_outerSize;
+    int m_innerSize;
+    int m_nnz;
+    int* m_outerIndex;
+    int* m_innerIndices;
+    Scalar* m_values;
+
+  public:
+
+    inline int rows() const { return IsRowMajor ? m_outerSize : m_innerSize; }
+    inline int cols() const { return IsRowMajor ? m_innerSize : m_outerSize; }
+    inline int innerSize() const { return m_innerSize; }
+    inline int outerSize() const { return m_outerSize; }
+    inline int innerNonZeros(int j) const { return m_outerIndex[j+1]-m_outerIndex[j]; }
+
+    //----------------------------------------
+    // direct access interface
+    inline const Scalar* _valuePtr() const { return m_values; }
+    inline Scalar* _valuePtr() { return m_values; }
+
+    inline const int* _innerIndexPtr() const { return m_innerIndices; }
+    inline int* _innerIndexPtr() { return m_innerIndices; }
+
+    inline const int* _outerIndexPtr() const { return m_outerIndex; }
+    inline int* _outerIndexPtr() { return m_outerIndex; }
+    //----------------------------------------
+
+    inline Scalar coeff(int row, int col) const
+    {
+      const int outer = RowMajor ? row : col;
+      const int inner = RowMajor ? col : row;
+
+      int start = m_outerIndex[outer];
+      int end = m_outerIndex[outer+1];
+      if (start==end)
+        return Scalar(0);
+      else if (end>0 && inner==m_innerIndices[end-1])
+        return m_values[end-1];
+      // ^^  optimization: let's first check if it is the last coefficient
+      // (very common in high level algorithms)
+
+      const int* r = std::lower_bound(&m_innerIndices[start],&m_innerIndices[end-1],inner);
+      const int id = r-&m_innerIndices[0];
+      return ((*r==inner) && (id<end)) ? m_values[id] : Scalar(0);
+    }
+
+    inline Scalar& coeffRef(int row, int col)
+    {
+      const int outer = RowMajor ? row : col;
+      const int inner = RowMajor ? col : row;
+
+      int start = m_outerIndex[outer];
+      int end = m_outerIndex[outer+1];
+      ei_assert(end>=start && "you probably called coeffRef on a non finalized matrix");
+      ei_assert(end>start && "coeffRef cannot be called on a zero coefficient");
+      int* r = std::lower_bound(&m_innerIndices[start],&m_innerIndices[end],inner);
+      const int id = r-&m_innerIndices[0];
+      ei_assert((*r==inner) && (id<end) && "coeffRef cannot be called on a zero coefficient");
+      return m_values[id];
+    }
+
+    class InnerIterator;
+
+    /** \returns the number of non zero coefficients */
+    inline int nonZeros() const  { return m_nnz; }
+
+    inline MappedSparseMatrix(int rows, int cols, int nnz, int* outerIndexPtr, int* innerIndexPtr, Scalar* valuePtr)
+      : m_outerSize(IsRowMajor?rows:cols), m_innerSize(IsRowMajor?cols:rows), m_nnz(nnz), m_outerIndex(outerIndexPtr),
+        m_innerIndices(innerIndexPtr), m_values(valuePtr)
+    {}
+
+    #ifdef EIGEN_TAUCS_SUPPORT
+    explicit MappedSparseMatrix(taucs_ccs_matrix& taucsMatrix);
+    #endif
+
+    #ifdef EIGEN_CHOLMOD_SUPPORT
+    explicit MappedSparseMatrix(cholmod_sparse& cholmodMatrix);
+    #endif
+
+    #ifdef EIGEN_SUPERLU_SUPPORT
+    explicit MappedSparseMatrix(SluMatrix& sluMatrix);
+    #endif
+
+    /** Empty destructor */
+    inline ~MappedSparseMatrix() {}
+};
+
+template<typename Scalar, int _Flags>
+class MappedSparseMatrix<Scalar,_Flags>::InnerIterator
+{
+  public:
+    InnerIterator(const MappedSparseMatrix& mat, int outer)
+      : m_matrix(mat),
+        m_outer(outer),
+        m_id(mat._outerIndexPtr()[outer]),
+        m_start(m_id),
+        m_end(mat._outerIndexPtr()[outer+1])
+    {}
+
+    template<unsigned int Added, unsigned int Removed>
+    InnerIterator(const Flagged<MappedSparseMatrix,Added,Removed>& mat, int outer)
+      : m_matrix(mat._expression()), m_id(m_matrix._outerIndexPtr()[outer]),
+        m_start(m_id), m_end(m_matrix._outerIndexPtr()[outer+1])
+    {}
+
+    inline InnerIterator& operator++() { m_id++; return *this; }
+
+    inline Scalar value() const { return m_matrix._valuePtr()[m_id]; }
+    inline Scalar& valueRef() { return const_cast<Scalar&>(m_matrix._valuePtr()[m_id]); }
+
+    inline int index() const { return m_matrix._innerIndexPtr()[m_id]; }
+    inline int row() const { return IsRowMajor ? m_outer : index(); }
+    inline int col() const { return IsRowMajor ? index() : m_outer; }
+
+    inline operator bool() const { return (m_id < m_end) && (m_id>=m_start); }
+
+  protected:
+    const MappedSparseMatrix& m_matrix;
+    const int m_outer;
+    int m_id;
+    const int m_start;
+    const int m_end;
+};
+
+#endif // EIGEN_MAPPED_SPARSEMATRIX_H
diff --git a/extern/Eigen2/Eigen/src/Sparse/RandomSetter.h b/extern/Eigen2/Eigen/src/Sparse/RandomSetter.h
new file mode 100644
index 00000000000..d908e315f3b
--- /dev/null
+++ b/extern/Eigen2/Eigen/src/Sparse/RandomSetter.h
@@ -0,0 +1,330 @@
+// 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_RANDOMSETTER_H
+#define EIGEN_RANDOMSETTER_H
+
+/** Represents a std::map
+  *
+  * \see RandomSetter
+  */
+template<typename Scalar> struct StdMapTraits
+{
+  typedef int KeyType;
+  typedef std::map<KeyType,Scalar> Type;
+  enum {
+    IsSorted = 1
+  };
+
+  static void setInvalidKey(Type&, const KeyType&) {}
+};
+
+#ifdef EIGEN_UNORDERED_MAP_SUPPORT
+/** Represents a std::unordered_map
+  *
+  * To use it you need to both define EIGEN_UNORDERED_MAP_SUPPORT and include the unordered_map header file
+  * yourself making sure that unordered_map is defined in the std namespace.
+  * 
+  * For instance, with current version of gcc you can either enable C++0x standard (-std=c++0x) or do:
+  * \code
+  * #include <tr1/unordered_map>
+  * #define EIGEN_UNORDERED_MAP_SUPPORT
+  * namespace std {
+  *   using std::tr1::unordered_map;
+  * }
+  * \endcode
+  *
+  * \see RandomSetter
+  */
+template<typename Scalar> struct StdUnorderedMapTraits
+{
+  typedef int KeyType;
+  typedef std::unordered_map<KeyType,Scalar> Type;
+  enum {
+    IsSorted = 0
+  };
+
+  static void setInvalidKey(Type&, const KeyType&) {}
+};
+#endif // EIGEN_UNORDERED_MAP_SUPPORT
+
+#ifdef _DENSE_HASH_MAP_H_
+/** Represents a google::dense_hash_map
+  *
+  * \see RandomSetter
+  */
+template<typename Scalar> struct GoogleDenseHashMapTraits
+{
+  typedef int KeyType;
+  typedef google::dense_hash_map<KeyType,Scalar> Type;
+  enum {
+    IsSorted = 0
+  };
+
+  static void setInvalidKey(Type& map, const KeyType& k)
+  { map.set_empty_key(k); }
+};
+#endif
+
+#ifdef _SPARSE_HASH_MAP_H_
+/** Represents a google::sparse_hash_map
+  *
+  * \see RandomSetter
+  */
+template<typename Scalar> struct GoogleSparseHashMapTraits
+{
+  typedef int KeyType;
+  typedef google::sparse_hash_map<KeyType,Scalar> Type;
+  enum {
+    IsSorted = 0
+  };
+
+  static void setInvalidKey(Type&, const KeyType&) {}
+};
+#endif
+
+/** \class RandomSetter
+  *
+  * \brief The RandomSetter is a wrapper object allowing to set/update a sparse matrix with random access
+  *
+  * \param SparseMatrixType the type of the sparse matrix we are updating
+  * \param MapTraits a traits class representing the map implementation used for the temporary sparse storage.
+  *                  Its default value depends on the system.
+  * \param OuterPacketBits defines the number of rows (or columns) manage by a single map object
+  *                        as a power of two exponent.
+  *
+  * This class temporarily represents a sparse matrix object using a generic map implementation allowing for
+  * efficient random access. The conversion from the compressed representation to a hash_map object is performed
+  * in the RandomSetter constructor, while the sparse matrix is updated back at destruction time. This strategy
+  * suggest the use of nested blocks as in this example:
+  *
+  * \code
+  * SparseMatrix<double> m(rows,cols);
+  * {
+  *   RandomSetter<SparseMatrix<double> > w(m);
+  *   // don't use m but w instead with read/write random access to the coefficients:
+  *   for(;;)
+  *     w(rand(),rand()) = rand;
+  * }
+  * // when w is deleted, the data are copied back to m
+  * // and m is ready to use.
+  * \endcode
+  *
+  * Since hash_map objects are not fully sorted, representing a full matrix as a single hash_map would
+  * involve a big and costly sort to update the compressed matrix back. To overcome this issue, a RandomSetter
+  * use multiple hash_map, each representing 2^OuterPacketBits columns or rows according to the storage order.
+  * To reach optimal performance, this value should be adjusted according to the average number of nonzeros
+  * per rows/columns.
+  *
+  * The possible values for the template parameter MapTraits are:
+  *  - \b StdMapTraits: corresponds to std::map. (does not perform very well)
+  *  - \b GnuHashMapTraits: corresponds to __gnu_cxx::hash_map (available only with GCC)
+  *  - \b GoogleDenseHashMapTraits: corresponds to google::dense_hash_map (best efficiency, reasonable memory consumption)
+  *  - \b GoogleSparseHashMapTraits: corresponds to google::sparse_hash_map (best memory consumption, relatively good performance)
+  *
+  * The default map implementation depends on the availability, and the preferred order is:
+  * GoogleSparseHashMapTraits, GnuHashMapTraits, and finally StdMapTraits.
+  *
+  * For performance and memory consumption reasons it is highly recommended to use one of
+  * the Google's hash_map implementation. To enable the support for them, you have two options:
+  *  - \#include <google/dense_hash_map> yourself \b before Eigen/Sparse header
+  *  - define EIGEN_GOOGLEHASH_SUPPORT
+  * In the later case the inclusion of <google/dense_hash_map> is made for you.
+  * 
+  * \see http://code.google.com/p/google-sparsehash/
+  */
+template<typename SparseMatrixType,
+         template <typename T> class MapTraits =
+#if defined _DENSE_HASH_MAP_H_
+          GoogleDenseHashMapTraits
+#elif defined _HASH_MAP
+          GnuHashMapTraits
+#else
+          StdMapTraits
+#endif
+         ,int OuterPacketBits = 6>
+class RandomSetter
+{
+    typedef typename ei_traits<SparseMatrixType>::Scalar Scalar;
+    struct ScalarWrapper
+    {
+      ScalarWrapper() : value(0) {}
+      Scalar value;
+    };
+    typedef typename MapTraits<ScalarWrapper>::KeyType KeyType;
+    typedef typename MapTraits<ScalarWrapper>::Type HashMapType;
+    static const int OuterPacketMask = (1 << OuterPacketBits) - 1;
+    enum {
+      SwapStorage = 1 - MapTraits<ScalarWrapper>::IsSorted,
+      TargetRowMajor = (SparseMatrixType::Flags & RowMajorBit) ? 1 : 0,
+      SetterRowMajor = SwapStorage ? 1-TargetRowMajor : TargetRowMajor,
+      IsUpperTriangular = SparseMatrixType::Flags & UpperTriangularBit,
+      IsLowerTriangular = SparseMatrixType::Flags & LowerTriangularBit
+    };
+
+  public:
+
+    /** Constructs a random setter object from the sparse matrix \a target
+      *
+      * Note that the initial value of \a target are imported. If you want to re-set
+      * a sparse matrix from scratch, then you must set it to zero first using the
+      * setZero() function.
+      */
+    inline RandomSetter(SparseMatrixType& target)
+      : mp_target(&target)
+    {
+      const int outerSize = SwapStorage ? target.innerSize() : target.outerSize();
+      const int innerSize = SwapStorage ? target.outerSize() : target.innerSize();
+      m_outerPackets = outerSize >> OuterPacketBits;
+      if (outerSize&OuterPacketMask)
+        m_outerPackets += 1;
+      m_hashmaps = new HashMapType[m_outerPackets];
+      // compute number of bits needed to store inner indices
+      int aux = innerSize - 1;
+      m_keyBitsOffset = 0;
+      while (aux)
+      {
+        ++m_keyBitsOffset;
+        aux = aux >> 1;
+      }
+      KeyType ik = (1<<(OuterPacketBits+m_keyBitsOffset));
+      for (int k=0; k<m_outerPackets; ++k)
+        MapTraits<ScalarWrapper>::setInvalidKey(m_hashmaps[k],ik);
+
+      // insert current coeffs
+      for (int j=0; j<mp_target->outerSize(); ++j)
+        for (typename SparseMatrixType::InnerIterator it(*mp_target,j); it; ++it)
+          (*this)(TargetRowMajor?j:it.index(), TargetRowMajor?it.index():j) = it.value();
+    }
+
+    /** Destructor updating back the sparse matrix target */
+    ~RandomSetter()
+    {
+      KeyType keyBitsMask = (1<<m_keyBitsOffset)-1;
+      if (!SwapStorage) // also means the map is sorted
+      {
+        mp_target->startFill(nonZeros());
+        for (int k=0; k<m_outerPackets; ++k)
+        {
+          const int outerOffset = (1<<OuterPacketBits) * k;
+          typename HashMapType::iterator end = m_hashmaps[k].end();
+          for (typename HashMapType::iterator it = m_hashmaps[k].begin(); it!=end; ++it)
+          {
+            const int outer = (it->first >> m_keyBitsOffset) + outerOffset;
+            const int inner = it->first & keyBitsMask;
+            mp_target->fill(TargetRowMajor ? outer : inner, TargetRowMajor ? inner : outer) = it->second.value;
+          }
+        }
+        mp_target->endFill();
+      }
+      else
+      {
+        VectorXi positions(mp_target->outerSize());
+        positions.setZero();
+        // pass 1
+        for (int k=0; k<m_outerPackets; ++k)
+        {
+          typename HashMapType::iterator end = m_hashmaps[k].end();
+          for (typename HashMapType::iterator it = m_hashmaps[k].begin(); it!=end; ++it)
+          {
+            const int outer = it->first & keyBitsMask;
+            ++positions[outer];
+          }
+        }
+        // prefix sum
+        int count = 0;
+        for (int j=0; j<mp_target->outerSize(); ++j)
+        {
+          int tmp = positions[j];
+          mp_target->_outerIndexPtr()[j] = count;
+          positions[j] = count;
+          count += tmp;
+        }
+        mp_target->_outerIndexPtr()[mp_target->outerSize()] = count;
+        mp_target->resizeNonZeros(count);
+        // pass 2
+        for (int k=0; k<m_outerPackets; ++k)
+        {
+          const int outerOffset = (1<<OuterPacketBits) * k;
+          typename HashMapType::iterator end = m_hashmaps[k].end();
+          for (typename HashMapType::iterator it = m_hashmaps[k].begin(); it!=end; ++it)
+          {
+            const int inner = (it->first >> m_keyBitsOffset) + outerOffset;
+            const int outer = it->first & keyBitsMask;
+            // sorted insertion
+            // Note that we have to deal with at most 2^OuterPacketBits unsorted coefficients,
+            // moreover those 2^OuterPacketBits coeffs are likely to be sparse, an so only a
+            // small fraction of them have to be sorted, whence the following simple procedure:
+            int posStart = mp_target->_outerIndexPtr()[outer];
+            int i = (positions[outer]++) - 1;
+            while ( (i >= posStart) && (mp_target->_innerIndexPtr()[i] > inner) )
+            {
+              mp_target->_valuePtr()[i+1] = mp_target->_valuePtr()[i];
+              mp_target->_innerIndexPtr()[i+1] = mp_target->_innerIndexPtr()[i];
+              --i;
+            }
+            mp_target->_innerIndexPtr()[i+1] = inner;
+            mp_target->_valuePtr()[i+1] = it->second.value;
+          }
+        }
+      }
+      delete[] m_hashmaps;
+    }
+
+    /** \returns a reference to the coefficient at given coordinates \a row, \a col */
+    Scalar& operator() (int row, int col)
+    {
+      ei_assert(((!IsUpperTriangular) || (row<=col)) && "Invalid access to an upper triangular matrix");
+      ei_assert(((!IsLowerTriangular) || (col<=row)) && "Invalid access to an upper triangular matrix");
+      const int outer = SetterRowMajor ? row : col;
+      const int inner = SetterRowMajor ? col : row;
+      const int outerMajor = outer >> OuterPacketBits; // index of the packet/map
+      const int outerMinor = outer & OuterPacketMask;  // index of the inner vector in the packet
+      const KeyType key = (KeyType(outerMinor)<<m_keyBitsOffset) | inner;
+      return m_hashmaps[outerMajor][key].value;
+    }
+
+    /** \returns the number of non zero coefficients 
+      *
+      * \note According to the underlying map/hash_map implementation,
+      * this function might be quite expensive.
+      */
+    int nonZeros() const
+    {
+      int nz = 0;
+      for (int k=0; k<m_outerPackets; ++k)
+        nz += m_hashmaps[k].size();
+      return nz;
+    }
+
+
+  protected:
+
+    HashMapType* m_hashmaps;
+    SparseMatrixType* mp_target;
+    int m_outerPackets;
+    unsigned char m_keyBitsOffset;
+};
+
+#endif // EIGEN_RANDOMSETTER_H
diff --git a/extern/Eigen2/Eigen/src/Sparse/SparseAssign.h b/extern/Eigen2/Eigen/src/Sparse/SparseAssign.h
new file mode 100644
index 00000000000..e69de29bb2d
--- /dev/null
+++ b/extern/Eigen2/Eigen/src/Sparse/SparseAssign.h
diff --git a/extern/Eigen2/Eigen/src/Sparse/SparseBlock.h b/extern/Eigen2/Eigen/src/Sparse/SparseBlock.h
new file mode 100644
index 00000000000..c39066676b6
--- /dev/null
+++ b/extern/Eigen2/Eigen/src/Sparse/SparseBlock.h
@@ -0,0 +1,449 @@
+// 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>
+// 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/>.
+
+#ifndef EIGEN_SPARSE_BLOCK_H
+#define EIGEN_SPARSE_BLOCK_H
+
+template<typename MatrixType, int Size>
+struct ei_traits<SparseInnerVectorSet<MatrixType, Size> >
+{
+  typedef typename ei_traits<MatrixType>::Scalar Scalar;
+  enum {
+    IsRowMajor = (int(MatrixType::Flags)&RowMajorBit)==RowMajorBit,
+    Flags = MatrixType::Flags,
+    RowsAtCompileTime = IsRowMajor ? Size : MatrixType::RowsAtCompileTime,
+    ColsAtCompileTime = IsRowMajor ? MatrixType::ColsAtCompileTime : Size,
+    CoeffReadCost = MatrixType::CoeffReadCost
+  };
+};
+
+template<typename MatrixType, int Size>
+class SparseInnerVectorSet : ei_no_assignment_operator,
+  public SparseMatrixBase<SparseInnerVectorSet<MatrixType, Size> >
+{
+    enum { IsRowMajor = ei_traits<SparseInnerVectorSet>::IsRowMajor };
+  public:
+
+    EIGEN_SPARSE_GENERIC_PUBLIC_INTERFACE(SparseInnerVectorSet)
+    class InnerIterator: public MatrixType::InnerIterator
+    {
+      public:
+        inline InnerIterator(const SparseInnerVectorSet& xpr, int outer)
+          : MatrixType::InnerIterator(xpr.m_matrix, xpr.m_outerStart + outer)
+        {}
+    };
+
+    inline SparseInnerVectorSet(const MatrixType& matrix, int outerStart, int outerSize)
+      : m_matrix(matrix), m_outerStart(outerStart), m_outerSize(outerSize)
+    {
+      ei_assert( (outerStart>=0) && ((outerStart+outerSize)<=matrix.outerSize()) );
+    }
+
+    inline SparseInnerVectorSet(const MatrixType& matrix, int outer)
+      : m_matrix(matrix), m_outerStart(outer), m_outerSize(Size)
+    {
+      ei_assert(Size!=Dynamic);
+      ei_assert( (outer>=0) && (outer<matrix.outerSize()) );
+    }
+
+//     template<typename OtherDerived>
+//     inline SparseInnerVectorSet& operator=(const SparseMatrixBase<OtherDerived>& other)
+//     {
+//       return *this;
+//     }
+
+//     template<typename Sparse>
+//     inline SparseInnerVectorSet& operator=(const SparseMatrixBase<OtherDerived>& other)
+//     {
+//       return *this;
+//     }
+
+    EIGEN_STRONG_INLINE int rows() const { return IsRowMajor ? m_outerSize.value() : m_matrix.rows(); }
+    EIGEN_STRONG_INLINE int cols() const { return IsRowMajor ? m_matrix.cols() : m_outerSize.value(); }
+
+  protected:
+
+    const typename MatrixType::Nested m_matrix;
+    int m_outerStart;
+    const ei_int_if_dynamic<Size> m_outerSize;
+
+};
+
+/***************************************************************************
+* specialisation for DynamicSparseMatrix
+***************************************************************************/
+
+template<typename _Scalar, int _Options, int Size>
+class SparseInnerVectorSet<DynamicSparseMatrix<_Scalar, _Options>, Size>
+  : public SparseMatrixBase<SparseInnerVectorSet<DynamicSparseMatrix<_Scalar, _Options>, Size> >
+{
+    typedef DynamicSparseMatrix<_Scalar, _Options> MatrixType;
+    enum { IsRowMajor = ei_traits<SparseInnerVectorSet>::IsRowMajor };
+  public:
+
+    EIGEN_SPARSE_GENERIC_PUBLIC_INTERFACE(SparseInnerVectorSet)
+    class InnerIterator: public MatrixType::InnerIterator
+    {
+      public:
+        inline InnerIterator(const SparseInnerVectorSet& xpr, int outer)
+          : MatrixType::InnerIterator(xpr.m_matrix, xpr.m_outerStart + outer)
+        {}
+    };
+
+    inline SparseInnerVectorSet(const MatrixType& matrix, int outerStart, int outerSize)
+      : m_matrix(matrix), m_outerStart(outerStart), m_outerSize(outerSize)
+    {
+      ei_assert( (outerStart>=0) && ((outerStart+outerSize)<=matrix.outerSize()) );
+    }
+
+    inline SparseInnerVectorSet(const MatrixType& matrix, int outer)
+      : m_matrix(matrix), m_outerStart(outer), m_outerSize(Size)
+    {
+      ei_assert(Size!=Dynamic);
+      ei_assert( (outer>=0) && (outer<matrix.outerSize()) );
+    }
+
+    template<typename OtherDerived>
+    inline SparseInnerVectorSet& operator=(const SparseMatrixBase<OtherDerived>& other)
+    {
+      if (IsRowMajor != ((OtherDerived::Flags&RowMajorBit)==RowMajorBit))
+      {
+        // need to transpose => perform a block evaluation followed by a big swap
+        DynamicSparseMatrix<Scalar,IsRowMajor?RowMajorBit:0> aux(other);
+        *this = aux.markAsRValue();
+      }
+      else
+      {
+        // evaluate/copy vector per vector
+        for (int j=0; j<m_outerSize.value(); ++j)
+        {
+          SparseVector<Scalar,IsRowMajor ? RowMajorBit : 0> aux(other.innerVector(j));
+          m_matrix.const_cast_derived()._data()[m_outerStart+j].swap(aux._data());
+        }
+      }
+      return *this;
+    }
+
+    inline SparseInnerVectorSet& operator=(const SparseInnerVectorSet& other)
+    {
+      return operator=<SparseInnerVectorSet>(other);
+    }
+
+//     template<typename Sparse>
+//     inline SparseInnerVectorSet& operator=(const SparseMatrixBase<OtherDerived>& other)
+//     {
+//       return *this;
+//     }
+
+    EIGEN_STRONG_INLINE int rows() const { return IsRowMajor ? m_outerSize.value() : m_matrix.rows(); }
+    EIGEN_STRONG_INLINE int cols() const { return IsRowMajor ? m_matrix.cols() : m_outerSize.value(); }
+
+  protected:
+
+    const typename MatrixType::Nested m_matrix;
+    int m_outerStart;
+    const ei_int_if_dynamic<Size> m_outerSize;
+
+};
+
+
+/***************************************************************************
+* specialisation for SparseMatrix
+***************************************************************************/
+/*
+template<typename _Scalar, int _Options, int Size>
+class SparseInnerVectorSet<SparseMatrix<_Scalar, _Options>, Size>
+  : public SparseMatrixBase<SparseInnerVectorSet<SparseMatrix<_Scalar, _Options>, Size> >
+{
+    typedef DynamicSparseMatrix<_Scalar, _Options> MatrixType;
+    enum { IsRowMajor = ei_traits<SparseInnerVectorSet>::IsRowMajor };
+  public:
+
+    EIGEN_SPARSE_GENERIC_PUBLIC_INTERFACE(SparseInnerVectorSet)
+    class InnerIterator: public MatrixType::InnerIterator
+    {
+      public:
+        inline InnerIterator(const SparseInnerVectorSet& xpr, int outer)
+          : MatrixType::InnerIterator(xpr.m_matrix, xpr.m_outerStart + outer)
+        {}
+    };
+
+    inline SparseInnerVectorSet(const MatrixType& matrix, int outerStart, int outerSize)
+      : m_matrix(matrix), m_outerStart(outerStart), m_outerSize(outerSize)
+    {
+      ei_assert( (outerStart>=0) && ((outerStart+outerSize)<=matrix.outerSize()) );
+    }
+
+    inline SparseInnerVectorSet(const MatrixType& matrix, int outer)
+      : m_matrix(matrix), m_outerStart(outer)
+    {
+      ei_assert(Size==1);
+      ei_assert( (outer>=0) && (outer<matrix.outerSize()) );
+    }
+
+    template<typename OtherDerived>
+    inline SparseInnerVectorSet& operator=(const SparseMatrixBase<OtherDerived>& other)
+    {
+      if (IsRowMajor != ((OtherDerived::Flags&RowMajorBit)==RowMajorBit))
+      {
+        // need to transpose => perform a block evaluation followed by a big swap
+        DynamicSparseMatrix<Scalar,IsRowMajor?RowMajorBit:0> aux(other);
+        *this = aux.markAsRValue();
+      }
+      else
+      {
+        // evaluate/copy vector per vector
+        for (int j=0; j<m_outerSize.value(); ++j)
+        {
+          SparseVector<Scalar,IsRowMajor ? RowMajorBit : 0> aux(other.innerVector(j));
+          m_matrix.const_cast_derived()._data()[m_outerStart+j].swap(aux._data());
+        }
+      }
+      return *this;
+    }
+
+    inline SparseInnerVectorSet& operator=(const SparseInnerVectorSet& other)
+    {
+      return operator=<SparseInnerVectorSet>(other);
+    }
+
+    inline const Scalar* _valuePtr() const
+    { return m_matrix._valuePtr() + m_matrix._outerIndexPtr()[m_outerStart]; }
+    inline const int* _innerIndexPtr() const
+    { return m_matrix._innerIndexPtr() + m_matrix._outerIndexPtr()[m_outerStart]; }
+    inline const int* _outerIndexPtr() const { return m_matrix._outerIndexPtr() + m_outerStart; }
+
+//     template<typename Sparse>
+//     inline SparseInnerVectorSet& operator=(const SparseMatrixBase<OtherDerived>& other)
+//     {
+//       return *this;
+//     }
+
+    EIGEN_STRONG_INLINE int rows() const { return IsRowMajor ? m_outerSize.value() : m_matrix.rows(); }
+    EIGEN_STRONG_INLINE int cols() const { return IsRowMajor ? m_matrix.cols() : m_outerSize.value(); }
+
+  protected:
+
+    const typename MatrixType::Nested m_matrix;
+    int m_outerStart;
+    const ei_int_if_dynamic<Size> m_outerSize;
+
+};
+*/
+//----------
+
+/** \returns the i-th row of the matrix \c *this. For row-major matrix only. */
+template<typename Derived>
+SparseInnerVectorSet<Derived,1> SparseMatrixBase<Derived>::row(int i)
+{
+  EIGEN_STATIC_ASSERT(IsRowMajor,THIS_METHOD_IS_ONLY_FOR_ROW_MAJOR_MATRICES);
+  return innerVector(i);
+}
+
+/** \returns the i-th row of the matrix \c *this. For row-major matrix only.
+  * (read-only version) */
+template<typename Derived>
+const SparseInnerVectorSet<Derived,1> SparseMatrixBase<Derived>::row(int i) const
+{
+  EIGEN_STATIC_ASSERT(IsRowMajor,THIS_METHOD_IS_ONLY_FOR_ROW_MAJOR_MATRICES);
+  return innerVector(i);
+}
+
+/** \returns the i-th column of the matrix \c *this. For column-major matrix only. */
+template<typename Derived>
+SparseInnerVectorSet<Derived,1> SparseMatrixBase<Derived>::col(int i)
+{
+  EIGEN_STATIC_ASSERT(!IsRowMajor,THIS_METHOD_IS_ONLY_FOR_COLUMN_MAJOR_MATRICES);
+  return innerVector(i);
+}
+
+/** \returns the i-th column of the matrix \c *this. For column-major matrix only.
+  * (read-only version) */
+template<typename Derived>
+const SparseInnerVectorSet<Derived,1> SparseMatrixBase<Derived>::col(int i) const
+{
+  EIGEN_STATIC_ASSERT(!IsRowMajor,THIS_METHOD_IS_ONLY_FOR_COLUMN_MAJOR_MATRICES);
+  return innerVector(i);
+}
+
+/** \returns the \a outer -th column (resp. row) of the matrix \c *this if \c *this
+  * is col-major (resp. row-major).
+  */
+template<typename Derived>
+SparseInnerVectorSet<Derived,1> SparseMatrixBase<Derived>::innerVector(int outer)
+{ return SparseInnerVectorSet<Derived,1>(derived(), outer); }
+
+/** \returns the \a outer -th column (resp. row) of the matrix \c *this if \c *this
+  * is col-major (resp. row-major). Read-only.
+  */
+template<typename Derived>
+const SparseInnerVectorSet<Derived,1> SparseMatrixBase<Derived>::innerVector(int outer) const
+{ return SparseInnerVectorSet<Derived,1>(derived(), outer); }
+
+//----------
+
+/** \returns the i-th row of the matrix \c *this. For row-major matrix only. */
+template<typename Derived>
+SparseInnerVectorSet<Derived,Dynamic> SparseMatrixBase<Derived>::subrows(int start, int size)
+{
+  EIGEN_STATIC_ASSERT(IsRowMajor,THIS_METHOD_IS_ONLY_FOR_ROW_MAJOR_MATRICES);
+  return innerVectors(start, size);
+}
+
+/** \returns the i-th row of the matrix \c *this. For row-major matrix only.
+  * (read-only version) */
+template<typename Derived>
+const SparseInnerVectorSet<Derived,Dynamic> SparseMatrixBase<Derived>::subrows(int start, int size) const
+{
+  EIGEN_STATIC_ASSERT(IsRowMajor,THIS_METHOD_IS_ONLY_FOR_ROW_MAJOR_MATRICES);
+  return innerVectors(start, size);
+}
+
+/** \returns the i-th column of the matrix \c *this. For column-major matrix only. */
+template<typename Derived>
+SparseInnerVectorSet<Derived,Dynamic> SparseMatrixBase<Derived>::subcols(int start, int size)
+{
+  EIGEN_STATIC_ASSERT(!IsRowMajor,THIS_METHOD_IS_ONLY_FOR_COLUMN_MAJOR_MATRICES);
+  return innerVectors(start, size);
+}
+
+/** \returns the i-th column of the matrix \c *this. For column-major matrix only.
+  * (read-only version) */
+template<typename Derived>
+const SparseInnerVectorSet<Derived,Dynamic> SparseMatrixBase<Derived>::subcols(int start, int size) const
+{
+  EIGEN_STATIC_ASSERT(!IsRowMajor,THIS_METHOD_IS_ONLY_FOR_COLUMN_MAJOR_MATRICES);
+  return innerVectors(start, size);
+}
+
+/** \returns the \a outer -th column (resp. row) of the matrix \c *this if \c *this
+  * is col-major (resp. row-major).
+  */
+template<typename Derived>
+SparseInnerVectorSet<Derived,Dynamic> SparseMatrixBase<Derived>::innerVectors(int outerStart, int outerSize)
+{ return SparseInnerVectorSet<Derived,Dynamic>(derived(), outerStart, outerSize); }
+
+/** \returns the \a outer -th column (resp. row) of the matrix \c *this if \c *this
+  * is col-major (resp. row-major). Read-only.
+  */
+template<typename Derived>
+const SparseInnerVectorSet<Derived,Dynamic> SparseMatrixBase<Derived>::innerVectors(int outerStart, int outerSize) const
+{ return SparseInnerVectorSet<Derived,Dynamic>(derived(), outerStart, outerSize); }
+
+# if 0
+template<typename MatrixType, int BlockRows, int BlockCols, int PacketAccess>
+class Block<MatrixType,BlockRows,BlockCols,PacketAccess,IsSparse>
+  : public SparseMatrixBase<Block<MatrixType,BlockRows,BlockCols,PacketAccess,IsSparse> >
+{
+public:
+
+    _EIGEN_GENERIC_PUBLIC_INTERFACE(Block, SparseMatrixBase<Block>)
+    class InnerIterator;
+
+    /** Column or Row constructor
+      */
+    inline Block(const MatrixType& matrix, int i)
+      : m_matrix(matrix),
+        // It is a row if and only if BlockRows==1 and BlockCols==MatrixType::ColsAtCompileTime,
+        // and it is a column if and only if BlockRows==MatrixType::RowsAtCompileTime and BlockCols==1,
+        // all other cases are invalid.
+        // The case a 1x1 matrix seems ambiguous, but the result is the same anyway.
+        m_startRow( (BlockRows==1) && (BlockCols==MatrixType::ColsAtCompileTime) ? i : 0),
+        m_startCol( (BlockRows==MatrixType::RowsAtCompileTime) && (BlockCols==1) ? i : 0),
+        m_blockRows(matrix.rows()), // if it is a row, then m_blockRows has a fixed-size of 1, so no pb to try to overwrite it
+        m_blockCols(matrix.cols())  // same for m_blockCols
+    {
+      ei_assert( (i>=0) && (
+          ((BlockRows==1) && (BlockCols==MatrixType::ColsAtCompileTime) && i<matrix.rows())
+        ||((BlockRows==MatrixType::RowsAtCompileTime) && (BlockCols==1) && i<matrix.cols())));
+    }
+
+    /** Fixed-size constructor
+      */
+    inline Block(const MatrixType& matrix, int startRow, int startCol)
+      : m_matrix(matrix), m_startRow(startRow), m_startCol(startCol),
+        m_blockRows(matrix.rows()), m_blockCols(matrix.cols())
+    {
+      EIGEN_STATIC_ASSERT(RowsAtCompileTime!=Dynamic && RowsAtCompileTime!=Dynamic,THIS_METHOD_IS_ONLY_FOR_FIXED_SIZE)
+      ei_assert(startRow >= 0 && BlockRows >= 1 && startRow + BlockRows <= matrix.rows()
+          && startCol >= 0 && BlockCols >= 1 && startCol + BlockCols <= matrix.cols());
+    }
+
+    /** Dynamic-size constructor
+      */
+    inline Block(const MatrixType& matrix,
+          int startRow, int startCol,
+          int blockRows, int blockCols)
+      : m_matrix(matrix), m_startRow(startRow), m_startCol(startCol),
+                          m_blockRows(blockRows), m_blockCols(blockCols)
+    {
+      ei_assert((RowsAtCompileTime==Dynamic || RowsAtCompileTime==blockRows)
+          && (ColsAtCompileTime==Dynamic || ColsAtCompileTime==blockCols));
+      ei_assert(startRow >= 0 && blockRows >= 1 && startRow + blockRows <= matrix.rows()
+          && startCol >= 0 && blockCols >= 1 && startCol + blockCols <= matrix.cols());
+    }
+
+    inline int rows() const { return m_blockRows.value(); }
+    inline int cols() const { return m_blockCols.value(); }
+
+    inline int stride(void) const { return m_matrix.stride(); }
+
+    inline Scalar& coeffRef(int row, int col)
+    {
+      return m_matrix.const_cast_derived()
+               .coeffRef(row + m_startRow.value(), col + m_startCol.value());
+    }
+
+    inline const Scalar coeff(int row, int col) const
+    {
+      return m_matrix.coeff(row + m_startRow.value(), col + m_startCol.value());
+    }
+
+    inline Scalar& coeffRef(int index)
+    {
+      return m_matrix.const_cast_derived()
+             .coeffRef(m_startRow.value() + (RowsAtCompileTime == 1 ? 0 : index),
+                       m_startCol.value() + (RowsAtCompileTime == 1 ? index : 0));
+    }
+
+    inline const Scalar coeff(int index) const
+    {
+      return m_matrix
+             .coeff(m_startRow.value() + (RowsAtCompileTime == 1 ? 0 : index),
+                    m_startCol.value() + (RowsAtCompileTime == 1 ? index : 0));
+    }
+
+  protected:
+
+    const typename MatrixType::Nested m_matrix;
+    const ei_int_if_dynamic<MatrixType::RowsAtCompileTime == 1 ? 0 : Dynamic> m_startRow;
+    const ei_int_if_dynamic<MatrixType::ColsAtCompileTime == 1 ? 0 : Dynamic> m_startCol;
+    const ei_int_if_dynamic<RowsAtCompileTime> m_blockRows;
+    const ei_int_if_dynamic<ColsAtCompileTime> m_blockCols;
+
+};
+#endif
+
+#endif // EIGEN_SPARSE_BLOCK_H
diff --git a/extern/Eigen2/Eigen/src/Sparse/SparseCwise.h b/extern/Eigen2/Eigen/src/Sparse/SparseCwise.h
new file mode 100644
index 00000000000..2206883cc76
--- /dev/null
+++ b/extern/Eigen2/Eigen/src/Sparse/SparseCwise.h
@@ -0,0 +1,175 @@
+// 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>
+// Copyright (C) 2008 Benoit Jacob <jacob.benoit.1@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/>.
+
+#ifndef EIGEN_SPARSE_CWISE_H
+#define EIGEN_SPARSE_CWISE_H
+
+/** \internal
+  * convenient macro to defined the return type of a cwise binary operation */
+#define EIGEN_SPARSE_CWISE_BINOP_RETURN_TYPE(OP) \
+    CwiseBinaryOp<OP<typename ei_traits<ExpressionType>::Scalar>, ExpressionType, OtherDerived>
+
+#define EIGEN_SPARSE_CWISE_PRODUCT_RETURN_TYPE \
+    SparseCwiseBinaryOp< \
+      ei_scalar_product_op< \
+        typename ei_scalar_product_traits< \
+          typename ei_traits<ExpressionType>::Scalar, \
+          typename ei_traits<OtherDerived>::Scalar \
+        >::ReturnType \
+      >, \
+      ExpressionType, \
+      OtherDerived \
+    >
+
+/** \internal
+  * convenient macro to defined the return type of a cwise unary operation */
+#define EIGEN_SPARSE_CWISE_UNOP_RETURN_TYPE(OP) \
+    SparseCwiseUnaryOp<OP<typename ei_traits<ExpressionType>::Scalar>, ExpressionType>
+
+/** \internal
+  * convenient macro to defined the return type of a cwise comparison to a scalar */
+/*#define EIGEN_CWISE_COMP_TO_SCALAR_RETURN_TYPE(OP) \
+    CwiseBinaryOp<OP<typename ei_traits<ExpressionType>::Scalar>, ExpressionType, \
+        NestByValue<typename ExpressionType::ConstantReturnType> >*/
+
+template<typename ExpressionType> class SparseCwise
+{
+  public:
+
+    typedef typename ei_traits<ExpressionType>::Scalar Scalar;
+    typedef typename ei_meta_if<ei_must_nest_by_value<ExpressionType>::ret,
+        ExpressionType, const ExpressionType&>::ret ExpressionTypeNested;
+    typedef CwiseUnaryOp<ei_scalar_add_op<Scalar>, ExpressionType> ScalarAddReturnType;
+
+    inline SparseCwise(const ExpressionType& matrix) : m_matrix(matrix) {}
+
+    /** \internal */
+    inline const ExpressionType& _expression() const { return m_matrix; }
+
+    template<typename OtherDerived>
+    const EIGEN_SPARSE_CWISE_PRODUCT_RETURN_TYPE
+    operator*(const SparseMatrixBase<OtherDerived> &other) const;
+
+    template<typename OtherDerived>
+    const EIGEN_SPARSE_CWISE_PRODUCT_RETURN_TYPE
+    operator*(const MatrixBase<OtherDerived> &other) const;
+
+//     template<typename OtherDerived>
+//     const EIGEN_SPARSE_CWISE_BINOP_RETURN_TYPE(ei_scalar_quotient_op)
+//     operator/(const SparseMatrixBase<OtherDerived> &other) const;
+//
+//     template<typename OtherDerived>
+//     const EIGEN_SPARSE_CWISE_BINOP_RETURN_TYPE(ei_scalar_quotient_op)
+//     operator/(const MatrixBase<OtherDerived> &other) const;
+
+    template<typename OtherDerived>
+    const EIGEN_SPARSE_CWISE_BINOP_RETURN_TYPE(ei_scalar_min_op)
+    min(const SparseMatrixBase<OtherDerived> &other) const;
+
+    template<typename OtherDerived>
+    const EIGEN_SPARSE_CWISE_BINOP_RETURN_TYPE(ei_scalar_max_op)
+    max(const SparseMatrixBase<OtherDerived> &other) const;
+
+    const EIGEN_SPARSE_CWISE_UNOP_RETURN_TYPE(ei_scalar_abs_op)      abs() const;
+    const EIGEN_SPARSE_CWISE_UNOP_RETURN_TYPE(ei_scalar_abs2_op)     abs2() const;
+//     const EIGEN_SPARSE_CWISE_UNOP_RETURN_TYPE(ei_scalar_square_op)   square() const;
+//     const EIGEN_SPARSE_CWISE_UNOP_RETURN_TYPE(ei_scalar_cube_op)     cube() const;
+//     const EIGEN_SPARSE_CWISE_UNOP_RETURN_TYPE(ei_scalar_inverse_op)  inverse() const;
+//     const EIGEN_SPARSE_CWISE_UNOP_RETURN_TYPE(ei_scalar_sqrt_op)     sqrt() const;
+//     const EIGEN_SPARSE_CWISE_UNOP_RETURN_TYPE(ei_scalar_exp_op)      exp() const;
+//     const EIGEN_SPARSE_CWISE_UNOP_RETURN_TYPE(ei_scalar_log_op)      log() const;
+//     const EIGEN_SPARSE_CWISE_UNOP_RETURN_TYPE(ei_scalar_cos_op)      cos() const;
+//     const EIGEN_SPARSE_CWISE_UNOP_RETURN_TYPE(ei_scalar_sin_op)      sin() const;
+//     const EIGEN_SPARSE_CWISE_UNOP_RETURN_TYPE(ei_scalar_pow_op)      pow(const Scalar& exponent) const;
+
+    template<typename OtherDerived>
+    inline ExpressionType& operator*=(const SparseMatrixBase<OtherDerived> &other);
+
+//     template<typename OtherDerived>
+//     inline ExpressionType& operator/=(const SparseMatrixBase<OtherDerived> &other);
+
+    /*
+    template<typename OtherDerived> const EIGEN_CWISE_BINOP_RETURN_TYPE(std::less)
+    operator<(const MatrixBase<OtherDerived>& other) const;
+
+    template<typename OtherDerived> const EIGEN_CWISE_BINOP_RETURN_TYPE(std::less_equal)
+    operator<=(const MatrixBase<OtherDerived>& other) const;
+
+    template<typename OtherDerived> const EIGEN_CWISE_BINOP_RETURN_TYPE(std::greater)
+    operator>(const MatrixBase<OtherDerived>& other) const;
+
+    template<typename OtherDerived> const EIGEN_CWISE_BINOP_RETURN_TYPE(std::greater_equal)
+    operator>=(const MatrixBase<OtherDerived>& other) const;
+
+    template<typename OtherDerived> const EIGEN_CWISE_BINOP_RETURN_TYPE(std::equal_to)
+    operator==(const MatrixBase<OtherDerived>& other) const;
+
+    template<typename OtherDerived> const EIGEN_CWISE_BINOP_RETURN_TYPE(std::not_equal_to)
+    operator!=(const MatrixBase<OtherDerived>& other) const;
+
+    // comparisons to a scalar value
+    const EIGEN_CWISE_COMP_TO_SCALAR_RETURN_TYPE(std::less)
+    operator<(Scalar s) const;
+
+    const EIGEN_CWISE_COMP_TO_SCALAR_RETURN_TYPE(std::less_equal)
+    operator<=(Scalar s) const;
+
+    const EIGEN_CWISE_COMP_TO_SCALAR_RETURN_TYPE(std::greater)
+    operator>(Scalar s) const;
+
+    const EIGEN_CWISE_COMP_TO_SCALAR_RETURN_TYPE(std::greater_equal)
+    operator>=(Scalar s) const;
+
+    const EIGEN_CWISE_COMP_TO_SCALAR_RETURN_TYPE(std::equal_to)
+    operator==(Scalar s) const;
+
+    const EIGEN_CWISE_COMP_TO_SCALAR_RETURN_TYPE(std::not_equal_to)
+    operator!=(Scalar s) const;
+    */
+
+    // allow to extend SparseCwise outside Eigen
+    #ifdef EIGEN_SPARSE_CWISE_PLUGIN
+    #include EIGEN_SPARSE_CWISE_PLUGIN
+    #endif
+
+  protected:
+    ExpressionTypeNested m_matrix;
+};
+
+template<typename Derived>
+inline const SparseCwise<Derived>
+SparseMatrixBase<Derived>::cwise() const
+{
+  return derived();
+}
+
+template<typename Derived>
+inline SparseCwise<Derived>
+SparseMatrixBase<Derived>::cwise()
+{
+  return derived();
+}
+
+#endif // EIGEN_SPARSE_CWISE_H
diff --git a/extern/Eigen2/Eigen/src/Sparse/SparseCwiseBinaryOp.h b/extern/Eigen2/Eigen/src/Sparse/SparseCwiseBinaryOp.h
new file mode 100644
index 00000000000..d19970efcb1
--- /dev/null
+++ b/extern/Eigen2/Eigen/src/Sparse/SparseCwiseBinaryOp.h
@@ -0,0 +1,442 @@
+// 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_SPARSE_CWISE_BINARY_OP_H
+#define EIGEN_SPARSE_CWISE_BINARY_OP_H
+
+// Here we have to handle 3 cases:
+//  1 - sparse op dense
+//  2 - dense op sparse
+//  3 - sparse op sparse
+// We also need to implement a 4th iterator for:
+//  4 - dense op dense
+// Finally, we also need to distinguish between the product and other operations :
+//                configuration      returned mode
+//  1 - sparse op dense    product      sparse
+//                         generic      dense
+//  2 - dense op sparse    product      sparse
+//                         generic      dense
+//  3 - sparse op sparse   product      sparse
+//                         generic      sparse
+//  4 - dense op dense     product      dense
+//                         generic      dense
+
+template<typename BinaryOp, typename Lhs, typename Rhs>
+struct ei_traits<SparseCwiseBinaryOp<BinaryOp, Lhs, Rhs> >
+{
+  typedef typename ei_result_of<
+                     BinaryOp(
+                       typename Lhs::Scalar,
+                       typename Rhs::Scalar
+                     )
+                   >::type Scalar;
+  typedef typename Lhs::Nested LhsNested;
+  typedef typename Rhs::Nested RhsNested;
+  typedef typename ei_unref<LhsNested>::type _LhsNested;
+  typedef typename ei_unref<RhsNested>::type _RhsNested;
+  enum {
+    LhsCoeffReadCost = _LhsNested::CoeffReadCost,
+    RhsCoeffReadCost = _RhsNested::CoeffReadCost,
+    LhsFlags = _LhsNested::Flags,
+    RhsFlags = _RhsNested::Flags,
+    RowsAtCompileTime = Lhs::RowsAtCompileTime,
+    ColsAtCompileTime = Lhs::ColsAtCompileTime,
+    MaxRowsAtCompileTime = Lhs::MaxRowsAtCompileTime,
+    MaxColsAtCompileTime = Lhs::MaxColsAtCompileTime,
+    Flags = (int(LhsFlags) | int(RhsFlags)) & HereditaryBits,
+    CoeffReadCost = LhsCoeffReadCost + RhsCoeffReadCost + ei_functor_traits<BinaryOp>::Cost
+  };
+};
+
+template<typename BinaryOp, typename Lhs, typename Rhs>
+class SparseCwiseBinaryOp : ei_no_assignment_operator,
+  public SparseMatrixBase<SparseCwiseBinaryOp<BinaryOp, Lhs, Rhs> >
+{
+  public:
+
+    class InnerIterator;
+
+    EIGEN_SPARSE_GENERIC_PUBLIC_INTERFACE(SparseCwiseBinaryOp)
+    typedef typename ei_traits<SparseCwiseBinaryOp>::LhsNested LhsNested;
+    typedef typename ei_traits<SparseCwiseBinaryOp>::RhsNested RhsNested;
+    typedef typename ei_unref<LhsNested>::type _LhsNested;
+    typedef typename ei_unref<RhsNested>::type _RhsNested;
+
+    EIGEN_STRONG_INLINE SparseCwiseBinaryOp(const Lhs& lhs, const Rhs& rhs, const BinaryOp& func = BinaryOp())
+      : m_lhs(lhs), m_rhs(rhs), m_functor(func)
+    {
+      EIGEN_STATIC_ASSERT((_LhsNested::Flags&RowMajorBit)==(_RhsNested::Flags&RowMajorBit),
+        BOTH_MATRICES_MUST_HAVE_THE_SAME_STORAGE_ORDER)
+      EIGEN_STATIC_ASSERT((ei_functor_allows_mixing_real_and_complex<BinaryOp>::ret
+                           ? int(ei_is_same_type<typename Lhs::RealScalar, typename Rhs::RealScalar>::ret)
+                           : int(ei_is_same_type<typename Lhs::Scalar, typename Rhs::Scalar>::ret)),
+        YOU_MIXED_DIFFERENT_NUMERIC_TYPES__YOU_NEED_TO_USE_THE_CAST_METHOD_OF_MATRIXBASE_TO_CAST_NUMERIC_TYPES_EXPLICITLY)
+      // require the sizes to match
+      EIGEN_STATIC_ASSERT_SAME_MATRIX_SIZE(Lhs, Rhs)
+      ei_assert(lhs.rows() == rhs.rows() && lhs.cols() == rhs.cols());
+    }
+
+    EIGEN_STRONG_INLINE int rows() const { return m_lhs.rows(); }
+    EIGEN_STRONG_INLINE int cols() const { return m_lhs.cols(); }
+
+    EIGEN_STRONG_INLINE const _LhsNested& lhs() const { return m_lhs; }
+    EIGEN_STRONG_INLINE const _RhsNested& rhs() const { return m_rhs; }
+    EIGEN_STRONG_INLINE const BinaryOp& functor() const { return m_functor; }
+
+  protected:
+    const LhsNested m_lhs;
+    const RhsNested m_rhs;
+    const BinaryOp m_functor;
+};
+
+template<typename BinaryOp, typename Lhs, typename Rhs, typename Derived,
+  int _LhsStorageMode = int(Lhs::Flags) & SparseBit,
+  int _RhsStorageMode = int(Rhs::Flags) & SparseBit>
+class ei_sparse_cwise_binary_op_inner_iterator_selector;
+
+template<typename BinaryOp, typename Lhs, typename Rhs>
+class SparseCwiseBinaryOp<BinaryOp,Lhs,Rhs>::InnerIterator
+  : public ei_sparse_cwise_binary_op_inner_iterator_selector<BinaryOp,Lhs,Rhs, typename SparseCwiseBinaryOp<BinaryOp,Lhs,Rhs>::InnerIterator>
+{
+  public:
+    typedef ei_sparse_cwise_binary_op_inner_iterator_selector<
+      BinaryOp,Lhs,Rhs, InnerIterator> Base;
+
+    EIGEN_STRONG_INLINE InnerIterator(const SparseCwiseBinaryOp& binOp, int outer)
+      : Base(binOp,outer)
+    {}
+};
+
+/***************************************************************************
+* Implementation of inner-iterators
+***************************************************************************/
+
+// template<typename T> struct ei_func_is_conjunction { enum { ret = false }; };
+// template<typename T> struct ei_func_is_conjunction<ei_scalar_product_op<T> > { enum { ret = true }; };
+
+// TODO generalize the ei_scalar_product_op specialization to all conjunctions if any !
+
+// sparse - sparse  (generic)
+template<typename BinaryOp, typename Lhs, typename Rhs, typename Derived>
+class ei_sparse_cwise_binary_op_inner_iterator_selector<BinaryOp, Lhs, Rhs, Derived, IsSparse, IsSparse>
+{
+    typedef SparseCwiseBinaryOp<BinaryOp, Lhs, Rhs> CwiseBinaryXpr;
+    typedef typename ei_traits<CwiseBinaryXpr>::Scalar Scalar;
+    typedef typename ei_traits<CwiseBinaryXpr>::_LhsNested _LhsNested;
+    typedef typename ei_traits<CwiseBinaryXpr>::_RhsNested _RhsNested;
+    typedef typename _LhsNested::InnerIterator LhsIterator;
+    typedef typename _RhsNested::InnerIterator RhsIterator;
+  public:
+
+    EIGEN_STRONG_INLINE ei_sparse_cwise_binary_op_inner_iterator_selector(const CwiseBinaryXpr& xpr, int outer)
+      : m_lhsIter(xpr.lhs(),outer), m_rhsIter(xpr.rhs(),outer), m_functor(xpr.functor())
+    {
+      this->operator++();
+    }
+
+    EIGEN_STRONG_INLINE Derived& operator++()
+    {
+      if (m_lhsIter && m_rhsIter && (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;
+      }
+      else if (m_lhsIter && (!m_rhsIter || (m_lhsIter.index() < m_rhsIter.index())))
+      {
+        m_id = m_lhsIter.index();
+        m_value = m_functor(m_lhsIter.value(), Scalar(0));
+        ++m_lhsIter;
+      }
+      else if (m_rhsIter && (!m_lhsIter || (m_lhsIter.index() > m_rhsIter.index())))
+      {
+        m_id = m_rhsIter.index();
+        m_value = m_functor(Scalar(0), m_rhsIter.value());
+        ++m_rhsIter;
+      }
+      else
+      {
+        m_id = -1;
+      }
+      return *static_cast<Derived*>(this);
+    }
+
+    EIGEN_STRONG_INLINE Scalar value() const { return m_value; }
+
+    EIGEN_STRONG_INLINE int index() const { return m_id; }
+    EIGEN_STRONG_INLINE int row() const { return m_lhsIter.row(); }
+    EIGEN_STRONG_INLINE int col() const { return m_lhsIter.col(); }
+
+    EIGEN_STRONG_INLINE operator bool() const { return m_id>=0; }
+
+  protected:
+    LhsIterator m_lhsIter;
+    RhsIterator m_rhsIter;
+    const BinaryOp& m_functor;
+    Scalar m_value;
+    int m_id;
+};
+
+// sparse - sparse  (product)
+template<typename T, typename Lhs, typename Rhs, typename Derived>
+class ei_sparse_cwise_binary_op_inner_iterator_selector<ei_scalar_product_op<T>, Lhs, Rhs, Derived, IsSparse, IsSparse>
+{
+    typedef ei_scalar_product_op<T> BinaryFunc;
+    typedef SparseCwiseBinaryOp<BinaryFunc, Lhs, Rhs> CwiseBinaryXpr;
+    typedef typename CwiseBinaryXpr::Scalar Scalar;
+    typedef typename ei_traits<CwiseBinaryXpr>::_LhsNested _LhsNested;
+    typedef typename _LhsNested::InnerIterator LhsIterator;
+    typedef typename ei_traits<CwiseBinaryXpr>::_RhsNested _RhsNested;
+    typedef typename _RhsNested::InnerIterator RhsIterator;
+  public:
+
+    EIGEN_STRONG_INLINE ei_sparse_cwise_binary_op_inner_iterator_selector(const CwiseBinaryXpr& xpr, int outer)
+      : m_lhsIter(xpr.lhs(),outer), m_rhsIter(xpr.rhs(),outer), m_functor(xpr.functor())
+    {
+      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_lhsIter;
+      ++m_rhsIter;
+      while (m_lhsIter && m_rhsIter && (m_lhsIter.index() != m_rhsIter.index()))
+      {
+        if (m_lhsIter.index() < m_rhsIter.index())
+          ++m_lhsIter;
+        else
+          ++m_rhsIter;
+      }
+      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 int row() const { return m_lhsIter.row(); }
+    EIGEN_STRONG_INLINE int col() const { return m_lhsIter.col(); }
+
+    EIGEN_STRONG_INLINE operator bool() const { return (m_lhsIter && m_rhsIter); }
+
+  protected:
+    LhsIterator m_lhsIter;
+    RhsIterator m_rhsIter;
+    const BinaryFunc& m_functor;
+};
+
+// sparse - dense  (product)
+template<typename T, typename Lhs, typename Rhs, typename Derived>
+class ei_sparse_cwise_binary_op_inner_iterator_selector<ei_scalar_product_op<T>, Lhs, Rhs, Derived, IsSparse, IsDense>
+{
+    typedef ei_scalar_product_op<T> BinaryFunc;
+    typedef SparseCwiseBinaryOp<BinaryFunc, Lhs, Rhs> CwiseBinaryXpr;
+    typedef typename CwiseBinaryXpr::Scalar Scalar;
+    typedef typename ei_traits<CwiseBinaryXpr>::_LhsNested _LhsNested;
+    typedef typename ei_traits<CwiseBinaryXpr>::RhsNested RhsNested;
+    typedef typename _LhsNested::InnerIterator LhsIterator;
+    enum { IsRowMajor = (int(Lhs::Flags)&RowMajorBit)==RowMajorBit };
+  public:
+
+    EIGEN_STRONG_INLINE ei_sparse_cwise_binary_op_inner_iterator_selector(const CwiseBinaryXpr& xpr, int outer)
+      : m_rhs(xpr.rhs()), m_lhsIter(xpr.lhs(),outer), m_functor(xpr.functor()), m_outer(outer)
+    {}
+
+    EIGEN_STRONG_INLINE Derived& operator++()
+    {
+      ++m_lhsIter;
+      return *static_cast<Derived*>(this);
+    }
+
+    EIGEN_STRONG_INLINE Scalar value() const
+    { return m_functor(m_lhsIter.value(),
+                       m_rhs.coeff(IsRowMajor?m_outer:m_lhsIter.index(),IsRowMajor?m_lhsIter.index():m_outer)); }
+
+    EIGEN_STRONG_INLINE int index() const { return m_lhsIter.index(); }
+    EIGEN_STRONG_INLINE int row() const { return m_lhsIter.row(); }
+    EIGEN_STRONG_INLINE int col() const { return m_lhsIter.col(); }
+
+    EIGEN_STRONG_INLINE operator bool() const { return m_lhsIter; }
+
+  protected:
+    const RhsNested m_rhs;
+    LhsIterator m_lhsIter;
+    const BinaryFunc m_functor;
+    const int m_outer;
+};
+
+// sparse - dense  (product)
+template<typename T, typename Lhs, typename Rhs, typename Derived>
+class ei_sparse_cwise_binary_op_inner_iterator_selector<ei_scalar_product_op<T>, Lhs, Rhs, Derived, IsDense, IsSparse>
+{
+    typedef ei_scalar_product_op<T> BinaryFunc;
+    typedef SparseCwiseBinaryOp<BinaryFunc, Lhs, Rhs> CwiseBinaryXpr;
+    typedef typename CwiseBinaryXpr::Scalar Scalar;
+    typedef typename ei_traits<CwiseBinaryXpr>::_RhsNested _RhsNested;
+    typedef typename _RhsNested::InnerIterator RhsIterator;
+    enum { IsRowMajor = (int(Rhs::Flags)&RowMajorBit)==RowMajorBit };
+  public:
+
+    EIGEN_STRONG_INLINE ei_sparse_cwise_binary_op_inner_iterator_selector(const CwiseBinaryXpr& xpr, int outer)
+      : m_xpr(xpr), m_rhsIter(xpr.rhs(),outer), m_functor(xpr.functor()), m_outer(outer)
+    {}
+
+    EIGEN_STRONG_INLINE Derived& operator++()
+    {
+      ++m_rhsIter;
+      return *static_cast<Derived*>(this);
+    }
+
+    EIGEN_STRONG_INLINE Scalar value() const
+    { return m_functor(m_xpr.lhs().coeff(IsRowMajor?m_outer:m_rhsIter.index(),IsRowMajor?m_rhsIter.index():m_outer), m_rhsIter.value()); }
+
+    EIGEN_STRONG_INLINE int index() const { return m_rhsIter.index(); }
+    EIGEN_STRONG_INLINE int row() const { return m_rhsIter.row(); }
+    EIGEN_STRONG_INLINE int col() const { return m_rhsIter.col(); }
+
+    EIGEN_STRONG_INLINE operator bool() const { return m_rhsIter; }
+
+  protected:
+    const CwiseBinaryXpr& m_xpr;
+    RhsIterator m_rhsIter;
+    const BinaryFunc& m_functor;
+    const int m_outer;
+};
+
+
+/***************************************************************************
+* Implementation of SparseMatrixBase and SparseCwise functions/operators
+***************************************************************************/
+
+template<typename Derived>
+template<typename OtherDerived>
+EIGEN_STRONG_INLINE const SparseCwiseBinaryOp<ei_scalar_difference_op<typename ei_traits<Derived>::Scalar>,
+                                 Derived, OtherDerived>
+SparseMatrixBase<Derived>::operator-(const SparseMatrixBase<OtherDerived> &other) const
+{
+  return SparseCwiseBinaryOp<ei_scalar_difference_op<Scalar>,
+                       Derived, OtherDerived>(derived(), other.derived());
+}
+
+template<typename Derived>
+template<typename OtherDerived>
+EIGEN_STRONG_INLINE Derived &
+SparseMatrixBase<Derived>::operator-=(const SparseMatrixBase<OtherDerived> &other)
+{
+  return *this = derived() - other.derived();
+}
+
+template<typename Derived>
+template<typename OtherDerived>
+EIGEN_STRONG_INLINE const SparseCwiseBinaryOp<ei_scalar_sum_op<typename ei_traits<Derived>::Scalar>, Derived, OtherDerived>
+SparseMatrixBase<Derived>::operator+(const SparseMatrixBase<OtherDerived> &other) const
+{
+  return SparseCwiseBinaryOp<ei_scalar_sum_op<Scalar>, Derived, OtherDerived>(derived(), other.derived());
+}
+
+template<typename Derived>
+template<typename OtherDerived>
+EIGEN_STRONG_INLINE Derived &
+SparseMatrixBase<Derived>::operator+=(const SparseMatrixBase<OtherDerived>& other)
+{
+  return *this = derived() + other.derived();
+}
+
+template<typename ExpressionType>
+template<typename OtherDerived>
+EIGEN_STRONG_INLINE const EIGEN_SPARSE_CWISE_PRODUCT_RETURN_TYPE
+SparseCwise<ExpressionType>::operator*(const SparseMatrixBase<OtherDerived> &other) const
+{
+  return EIGEN_SPARSE_CWISE_PRODUCT_RETURN_TYPE(_expression(), other.derived());
+}
+
+template<typename ExpressionType>
+template<typename OtherDerived>
+EIGEN_STRONG_INLINE const EIGEN_SPARSE_CWISE_PRODUCT_RETURN_TYPE
+SparseCwise<ExpressionType>::operator*(const MatrixBase<OtherDerived> &other) const
+{
+  return EIGEN_SPARSE_CWISE_PRODUCT_RETURN_TYPE(_expression(), other.derived());
+}
+
+// template<typename ExpressionType>
+// template<typename OtherDerived>
+// EIGEN_STRONG_INLINE const EIGEN_SPARSE_CWISE_BINOP_RETURN_TYPE(ei_scalar_quotient_op)
+// SparseCwise<ExpressionType>::operator/(const SparseMatrixBase<OtherDerived> &other) const
+// {
+//   return EIGEN_SPARSE_CWISE_BINOP_RETURN_TYPE(ei_scalar_quotient_op)(_expression(), other.derived());
+// }
+//
+// template<typename ExpressionType>
+// template<typename OtherDerived>
+// EIGEN_STRONG_INLINE const EIGEN_SPARSE_CWISE_BINOP_RETURN_TYPE(ei_scalar_quotient_op)
+// SparseCwise<ExpressionType>::operator/(const MatrixBase<OtherDerived> &other) const
+// {
+//   return EIGEN_SPARSE_CWISE_BINOP_RETURN_TYPE(ei_scalar_quotient_op)(_expression(), other.derived());
+// }
+
+template<typename ExpressionType>
+template<typename OtherDerived>
+inline ExpressionType& SparseCwise<ExpressionType>::operator*=(const SparseMatrixBase<OtherDerived> &other)
+{
+  return m_matrix.const_cast_derived() = _expression() * other.derived();
+}
+
+// template<typename ExpressionType>
+// template<typename OtherDerived>
+// inline ExpressionType& SparseCwise<ExpressionType>::operator/=(const SparseMatrixBase<OtherDerived> &other)
+// {
+//   return m_matrix.const_cast_derived() = *this / other;
+// }
+
+template<typename ExpressionType>
+template<typename OtherDerived>
+EIGEN_STRONG_INLINE const EIGEN_SPARSE_CWISE_BINOP_RETURN_TYPE(ei_scalar_min_op)
+SparseCwise<ExpressionType>::min(const SparseMatrixBase<OtherDerived> &other) const
+{
+  return EIGEN_SPARSE_CWISE_BINOP_RETURN_TYPE(ei_scalar_min_op)(_expression(), other.derived());
+}
+
+template<typename ExpressionType>
+template<typename OtherDerived>
+EIGEN_STRONG_INLINE const EIGEN_SPARSE_CWISE_BINOP_RETURN_TYPE(ei_scalar_max_op)
+SparseCwise<ExpressionType>::max(const SparseMatrixBase<OtherDerived> &other) const
+{
+  return EIGEN_SPARSE_CWISE_BINOP_RETURN_TYPE(ei_scalar_max_op)(_expression(), other.derived());
+}
+
+// template<typename Derived>
+// template<typename CustomBinaryOp, typename OtherDerived>
+// EIGEN_STRONG_INLINE const CwiseBinaryOp<CustomBinaryOp, Derived, OtherDerived>
+// SparseMatrixBase<Derived>::binaryExpr(const SparseMatrixBase<OtherDerived> &other, const CustomBinaryOp& func) const
+// {
+//   return CwiseBinaryOp<CustomBinaryOp, Derived, OtherDerived>(derived(), other.derived(), func);
+// }
+
+#endif // EIGEN_SPARSE_CWISE_BINARY_OP_H
diff --git a/extern/Eigen2/Eigen/src/Sparse/SparseCwiseUnaryOp.h b/extern/Eigen2/Eigen/src/Sparse/SparseCwiseUnaryOp.h
new file mode 100644
index 00000000000..b11c0f8a377
--- /dev/null
+++ b/extern/Eigen2/Eigen/src/Sparse/SparseCwiseUnaryOp.h
@@ -0,0 +1,183 @@
+// 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_SPARSE_CWISE_UNARY_OP_H
+#define EIGEN_SPARSE_CWISE_UNARY_OP_H
+
+template<typename UnaryOp, typename MatrixType>
+struct ei_traits<SparseCwiseUnaryOp<UnaryOp, MatrixType> > : ei_traits<MatrixType>
+{
+  typedef typename ei_result_of<
+                     UnaryOp(typename MatrixType::Scalar)
+                   >::type Scalar;
+  typedef typename MatrixType::Nested MatrixTypeNested;
+  typedef typename ei_unref<MatrixTypeNested>::type _MatrixTypeNested;
+  enum {
+    CoeffReadCost = _MatrixTypeNested::CoeffReadCost + ei_functor_traits<UnaryOp>::Cost
+  };
+};
+
+template<typename UnaryOp, typename MatrixType>
+class SparseCwiseUnaryOp : ei_no_assignment_operator,
+  public SparseMatrixBase<SparseCwiseUnaryOp<UnaryOp, MatrixType> >
+{
+  public:
+
+    class InnerIterator;
+//     typedef typename ei_unref<LhsNested>::type _LhsNested;
+
+    EIGEN_SPARSE_GENERIC_PUBLIC_INTERFACE(SparseCwiseUnaryOp)
+
+    inline SparseCwiseUnaryOp(const MatrixType& mat, const UnaryOp& func = UnaryOp())
+      : m_matrix(mat), m_functor(func) {}
+
+    EIGEN_STRONG_INLINE int rows() const { return m_matrix.rows(); }
+    EIGEN_STRONG_INLINE int cols() const { return m_matrix.cols(); }
+
+//     EIGEN_STRONG_INLINE const typename MatrixType::Nested& _matrix() const { return m_matrix; }
+//     EIGEN_STRONG_INLINE const UnaryOp& _functor() const { return m_functor; }
+
+  protected:
+    const typename MatrixType::Nested m_matrix;
+    const UnaryOp m_functor;
+};
+
+
+template<typename UnaryOp, typename MatrixType>
+class SparseCwiseUnaryOp<UnaryOp,MatrixType>::InnerIterator
+{
+    typedef typename SparseCwiseUnaryOp::Scalar Scalar;
+    typedef typename ei_traits<SparseCwiseUnaryOp>::_MatrixTypeNested _MatrixTypeNested;
+    typedef typename _MatrixTypeNested::InnerIterator MatrixTypeIterator;
+  public:
+
+    EIGEN_STRONG_INLINE InnerIterator(const SparseCwiseUnaryOp& unaryOp, int outer)
+      : m_iter(unaryOp.m_matrix,outer), m_functor(unaryOp.m_functor)
+    {}
+
+    EIGEN_STRONG_INLINE InnerIterator& operator++()
+    { ++m_iter; return *this; }
+
+    EIGEN_STRONG_INLINE Scalar value() const { return m_functor(m_iter.value()); }
+
+    EIGEN_STRONG_INLINE int index() const { return m_iter.index(); }
+    EIGEN_STRONG_INLINE int row() const { return m_iter.row(); }
+    EIGEN_STRONG_INLINE int col() const { return m_iter.col(); }
+
+    EIGEN_STRONG_INLINE operator bool() const { return m_iter; }
+
+  protected:
+    MatrixTypeIterator m_iter;
+    const UnaryOp m_functor;
+};
+
+template<typename Derived>
+template<typename CustomUnaryOp>
+EIGEN_STRONG_INLINE const SparseCwiseUnaryOp<CustomUnaryOp, Derived>
+SparseMatrixBase<Derived>::unaryExpr(const CustomUnaryOp& func) const
+{
+  return SparseCwiseUnaryOp<CustomUnaryOp, Derived>(derived(), func);
+}
+
+template<typename Derived>
+EIGEN_STRONG_INLINE const SparseCwiseUnaryOp<ei_scalar_opposite_op<typename ei_traits<Derived>::Scalar>,Derived>
+SparseMatrixBase<Derived>::operator-() const
+{
+  return derived();
+}
+
+template<typename ExpressionType>
+EIGEN_STRONG_INLINE const EIGEN_SPARSE_CWISE_UNOP_RETURN_TYPE(ei_scalar_abs_op)
+SparseCwise<ExpressionType>::abs() const
+{
+  return _expression();
+}
+
+template<typename ExpressionType>
+EIGEN_STRONG_INLINE const EIGEN_SPARSE_CWISE_UNOP_RETURN_TYPE(ei_scalar_abs2_op)
+SparseCwise<ExpressionType>::abs2() const
+{
+  return _expression();
+}
+
+template<typename Derived>
+EIGEN_STRONG_INLINE typename SparseMatrixBase<Derived>::ConjugateReturnType
+SparseMatrixBase<Derived>::conjugate() const
+{
+  return ConjugateReturnType(derived());
+}
+
+template<typename Derived>
+EIGEN_STRONG_INLINE const typename SparseMatrixBase<Derived>::RealReturnType
+SparseMatrixBase<Derived>::real() const { return derived(); }
+
+template<typename Derived>
+EIGEN_STRONG_INLINE const typename SparseMatrixBase<Derived>::ImagReturnType
+SparseMatrixBase<Derived>::imag() const { return derived(); }
+
+template<typename Derived>
+template<typename NewType>
+EIGEN_STRONG_INLINE const SparseCwiseUnaryOp<ei_scalar_cast_op<typename ei_traits<Derived>::Scalar, NewType>, Derived>
+SparseMatrixBase<Derived>::cast() const
+{
+  return derived();
+}
+
+template<typename Derived>
+EIGEN_STRONG_INLINE const SparseCwiseUnaryOp<ei_scalar_multiple_op<typename ei_traits<Derived>::Scalar>, Derived>
+SparseMatrixBase<Derived>::operator*(const Scalar& scalar) const
+{
+  return SparseCwiseUnaryOp<ei_scalar_multiple_op<Scalar>, Derived>
+    (derived(), ei_scalar_multiple_op<Scalar>(scalar));
+}
+
+template<typename Derived>
+EIGEN_STRONG_INLINE const SparseCwiseUnaryOp<ei_scalar_quotient1_op<typename ei_traits<Derived>::Scalar>, Derived>
+SparseMatrixBase<Derived>::operator/(const Scalar& scalar) const
+{
+  return SparseCwiseUnaryOp<ei_scalar_quotient1_op<Scalar>, Derived>
+    (derived(), ei_scalar_quotient1_op<Scalar>(scalar));
+}
+
+template<typename Derived>
+EIGEN_STRONG_INLINE Derived&
+SparseMatrixBase<Derived>::operator*=(const Scalar& other)
+{
+  for (int j=0; j<outerSize(); ++j)
+    for (typename Derived::InnerIterator i(derived(),j); i; ++i)
+      i.valueRef() *= other;
+  return derived();
+}
+
+template<typename Derived>
+EIGEN_STRONG_INLINE Derived&
+SparseMatrixBase<Derived>::operator/=(const Scalar& other)
+{
+  for (int j=0; j<outerSize(); ++j)
+    for (typename Derived::InnerIterator i(derived(),j); i; ++i)
+      i.valueRef() /= other;
+  return derived();
+}
+
+#endif // EIGEN_SPARSE_CWISE_UNARY_OP_H
diff --git a/extern/Eigen2/Eigen/src/Sparse/SparseDiagonalProduct.h b/extern/Eigen2/Eigen/src/Sparse/SparseDiagonalProduct.h
new file mode 100644
index 00000000000..932daf220b9
--- /dev/null
+++ b/extern/Eigen2/Eigen/src/Sparse/SparseDiagonalProduct.h
@@ -0,0 +1,157 @@
+// This file is part of Eigen, a lightweight C++ template library
+// for linear algebra. Eigen itself is part of the KDE project.
+//
+// Copyright (C) 2009 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_SPARSE_DIAGONAL_PRODUCT_H
+#define EIGEN_SPARSE_DIAGONAL_PRODUCT_H
+
+// the product a diagonal matrix with a sparse matrix can be easily
+// implemented using expression template. We have two very different cases:
+// 1 - diag * row-major sparse
+//     => each inner vector <=> scalar * sparse vector product
+//     => so we can reuse CwiseUnaryOp::InnerIterator
+// 2 - diag * col-major sparse
+//     => each inner vector <=> densevector * sparse vector cwise product
+//     => again, we can reuse specialization of CwiseBinaryOp::InnerIterator
+//        for that particular case
+// The two other cases are symmetric.
+
+template<typename Lhs, typename Rhs>
+struct ei_traits<SparseDiagonalProduct<Lhs, Rhs> > : ei_traits<SparseProduct<Lhs, Rhs, DiagonalProduct> >
+{
+  typedef typename ei_cleantype<Lhs>::type _Lhs;
+  typedef typename ei_cleantype<Rhs>::type _Rhs;
+  enum {
+    SparseFlags = ((int(_Lhs::Flags)&Diagonal)==Diagonal) ? int(_Rhs::Flags) : int(_Lhs::Flags),
+    Flags = SparseBit | (SparseFlags&RowMajorBit)
+  };
+};
+
+enum {SDP_IsDiagonal, SDP_IsSparseRowMajor, SDP_IsSparseColMajor};
+template<typename Lhs, typename Rhs, typename SparseDiagonalProductType, int RhsMode, int LhsMode> 
+class ei_sparse_diagonal_product_inner_iterator_selector;
+
+template<typename LhsNested, typename RhsNested>
+class SparseDiagonalProduct : public SparseMatrixBase<SparseDiagonalProduct<LhsNested,RhsNested> >, ei_no_assignment_operator
+{
+    typedef typename ei_traits<SparseDiagonalProduct>::_LhsNested _LhsNested;
+    typedef typename ei_traits<SparseDiagonalProduct>::_RhsNested _RhsNested;
+    
+    enum {
+      LhsMode = (_LhsNested::Flags&Diagonal)==Diagonal ? SDP_IsDiagonal
+              : (_LhsNested::Flags&RowMajorBit) ? SDP_IsSparseRowMajor : SDP_IsSparseColMajor,
+      RhsMode = (_RhsNested::Flags&Diagonal)==Diagonal ? SDP_IsDiagonal
+              : (_RhsNested::Flags&RowMajorBit) ? SDP_IsSparseRowMajor : SDP_IsSparseColMajor
+    };
+
+  public:
+
+    EIGEN_SPARSE_GENERIC_PUBLIC_INTERFACE(SparseDiagonalProduct)
+    
+    typedef ei_sparse_diagonal_product_inner_iterator_selector
+                <_LhsNested,_RhsNested,SparseDiagonalProduct,LhsMode,RhsMode> InnerIterator;
+
+    template<typename Lhs, typename Rhs>
+    EIGEN_STRONG_INLINE SparseDiagonalProduct(const Lhs& lhs, const Rhs& rhs)
+      : m_lhs(lhs), m_rhs(rhs)
+    {
+      ei_assert(lhs.cols() == rhs.rows() && "invalid sparse matrix * diagonal matrix product");
+    }
+
+    EIGEN_STRONG_INLINE int rows() const { return m_lhs.rows(); }
+    EIGEN_STRONG_INLINE int cols() const { return m_rhs.cols(); }
+
+    EIGEN_STRONG_INLINE const _LhsNested& lhs() const { return m_lhs; }
+    EIGEN_STRONG_INLINE const _RhsNested& rhs() const { return m_rhs; }
+
+  protected:
+    LhsNested m_lhs;
+    RhsNested m_rhs;
+};
+
+
+template<typename Lhs, typename Rhs, typename SparseDiagonalProductType>
+class ei_sparse_diagonal_product_inner_iterator_selector
+<Lhs,Rhs,SparseDiagonalProductType,SDP_IsDiagonal,SDP_IsSparseRowMajor>
+  : public SparseCwiseUnaryOp<ei_scalar_multiple_op<typename Lhs::Scalar>,Rhs>::InnerIterator
+{
+    typedef typename SparseCwiseUnaryOp<ei_scalar_multiple_op<typename Lhs::Scalar>,Rhs>::InnerIterator Base;
+  public:
+    inline ei_sparse_diagonal_product_inner_iterator_selector(
+              const SparseDiagonalProductType& expr, int outer)
+      : Base(expr.rhs()*(expr.lhs().diagonal().coeff(outer)), outer)
+    {}
+};
+
+template<typename Lhs, typename Rhs, typename SparseDiagonalProductType>
+class ei_sparse_diagonal_product_inner_iterator_selector
+<Lhs,Rhs,SparseDiagonalProductType,SDP_IsDiagonal,SDP_IsSparseColMajor>
+  : public SparseCwiseBinaryOp<
+      ei_scalar_product_op<typename Lhs::Scalar>,
+      SparseInnerVectorSet<Rhs,1>,
+      typename Lhs::_CoeffsVectorType>::InnerIterator
+{
+    typedef typename SparseCwiseBinaryOp<
+      ei_scalar_product_op<typename Lhs::Scalar>,
+      SparseInnerVectorSet<Rhs,1>,
+      typename Lhs::_CoeffsVectorType>::InnerIterator Base;
+  public:
+    inline ei_sparse_diagonal_product_inner_iterator_selector(
+              const SparseDiagonalProductType& expr, int outer)
+      : Base(expr.rhs().innerVector(outer) .cwise()* expr.lhs().diagonal(), 0)
+    {}
+};
+
+template<typename Lhs, typename Rhs, typename SparseDiagonalProductType>
+class ei_sparse_diagonal_product_inner_iterator_selector
+<Lhs,Rhs,SparseDiagonalProductType,SDP_IsSparseColMajor,SDP_IsDiagonal>
+  : public SparseCwiseUnaryOp<ei_scalar_multiple_op<typename Rhs::Scalar>,Lhs>::InnerIterator
+{
+    typedef typename SparseCwiseUnaryOp<ei_scalar_multiple_op<typename Rhs::Scalar>,Lhs>::InnerIterator Base;
+  public:
+    inline ei_sparse_diagonal_product_inner_iterator_selector(
+              const SparseDiagonalProductType& expr, int outer)
+      : Base(expr.lhs()*expr.rhs().diagonal().coeff(outer), outer)
+    {}
+};
+
+template<typename Lhs, typename Rhs, typename SparseDiagonalProductType>
+class ei_sparse_diagonal_product_inner_iterator_selector
+<Lhs,Rhs,SparseDiagonalProductType,SDP_IsSparseRowMajor,SDP_IsDiagonal>
+  : public SparseCwiseBinaryOp<
+      ei_scalar_product_op<typename Rhs::Scalar>,
+      SparseInnerVectorSet<Lhs,1>,
+      NestByValue<Transpose<typename Rhs::_CoeffsVectorType> > >::InnerIterator
+{
+    typedef typename SparseCwiseBinaryOp<
+      ei_scalar_product_op<typename Rhs::Scalar>,
+      SparseInnerVectorSet<Lhs,1>,
+      NestByValue<Transpose<typename Rhs::_CoeffsVectorType> > >::InnerIterator Base;
+  public:
+    inline ei_sparse_diagonal_product_inner_iterator_selector(
+              const SparseDiagonalProductType& expr, int outer)
+      : Base(expr.lhs().innerVector(outer) .cwise()* expr.rhs().diagonal().transpose().nestByValue(), 0)
+    {}
+};
+
+#endif // EIGEN_SPARSE_DIAGONAL_PRODUCT_H
diff --git a/extern/Eigen2/Eigen/src/Sparse/SparseDot.h b/extern/Eigen2/Eigen/src/Sparse/SparseDot.h
new file mode 100644
index 00000000000..7a26e0f4ba5
--- /dev/null
+++ b/extern/Eigen2/Eigen/src/Sparse/SparseDot.h
@@ -0,0 +1,97 @@
+// 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_SPARSE_DOT_H
+#define EIGEN_SPARSE_DOT_H
+
+template<typename Derived>
+template<typename OtherDerived>
+typename ei_traits<Derived>::Scalar
+SparseMatrixBase<Derived>::dot(const MatrixBase<OtherDerived>& other) const
+{
+  EIGEN_STATIC_ASSERT_VECTOR_ONLY(Derived)
+  EIGEN_STATIC_ASSERT_VECTOR_ONLY(OtherDerived)
+  EIGEN_STATIC_ASSERT_SAME_VECTOR_SIZE(Derived,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(size() == other.size());
+  ei_assert(other.size()>0 && "you are using a non initialized vector");
+  
+  typename Derived::InnerIterator i(derived(),0);
+  Scalar res = 0;
+  while (i)
+  {
+    res += i.value() * ei_conj(other.coeff(i.index()));
+    ++i;
+  }
+  return res;
+}
+
+template<typename Derived>
+template<typename OtherDerived>
+typename ei_traits<Derived>::Scalar
+SparseMatrixBase<Derived>::dot(const SparseMatrixBase<OtherDerived>& other) const
+{
+  EIGEN_STATIC_ASSERT_VECTOR_ONLY(Derived)
+  EIGEN_STATIC_ASSERT_VECTOR_ONLY(OtherDerived)
+  EIGEN_STATIC_ASSERT_SAME_VECTOR_SIZE(Derived,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(size() == other.size());
+  
+  typename Derived::InnerIterator i(derived(),0);
+  typename OtherDerived::InnerIterator j(other.derived(),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;
+}
+
+template<typename Derived>
+inline typename NumTraits<typename ei_traits<Derived>::Scalar>::Real
+SparseMatrixBase<Derived>::squaredNorm() const
+{
+  return ei_real((*this).cwise().abs2().sum());
+}
+
+template<typename Derived>
+inline typename NumTraits<typename ei_traits<Derived>::Scalar>::Real
+SparseMatrixBase<Derived>::norm() const
+{
+  return ei_sqrt(squaredNorm());
+}
+
+#endif // EIGEN_SPARSE_DOT_H
diff --git a/extern/Eigen2/Eigen/src/Sparse/SparseFlagged.h b/extern/Eigen2/Eigen/src/Sparse/SparseFlagged.h
new file mode 100644
index 00000000000..c47e162f538
--- /dev/null
+++ b/extern/Eigen2/Eigen/src/Sparse/SparseFlagged.h
@@ -0,0 +1,97 @@
+// 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 Benoit Jacob <jacob.benoit.1@gmail.com>
+// 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_SPARSE_FLAGGED_H
+#define EIGEN_SPARSE_FLAGGED_H
+
+template<typename ExpressionType, unsigned int Added, unsigned int Removed>
+struct ei_traits<SparseFlagged<ExpressionType, Added, Removed> > : ei_traits<ExpressionType>
+{
+  enum { Flags = (ExpressionType::Flags | Added) & ~Removed };
+};
+
+template<typename ExpressionType, unsigned int Added, unsigned int Removed> class SparseFlagged
+  : public SparseMatrixBase<SparseFlagged<ExpressionType, Added, Removed> >
+{
+  public:
+
+    EIGEN_SPARSE_GENERIC_PUBLIC_INTERFACE(SparseFlagged)
+    class InnerIterator;
+    class ReverseInnerIterator;
+    
+    typedef typename ei_meta_if<ei_must_nest_by_value<ExpressionType>::ret,
+        ExpressionType, const ExpressionType&>::ret ExpressionTypeNested;
+
+    inline SparseFlagged(const ExpressionType& matrix) : m_matrix(matrix) {}
+
+    inline int rows() const { return m_matrix.rows(); }
+    inline int cols() const { return m_matrix.cols(); }
+    
+    // FIXME should be keep them ?
+    inline Scalar& coeffRef(int row, int col)
+    { return m_matrix.const_cast_derived().coeffRef(col, row); }
+
+    inline const Scalar coeff(int row, int col) const
+    { return m_matrix.coeff(col, row); }
+
+    inline const Scalar coeff(int index) const
+    { return m_matrix.coeff(index); }
+
+    inline Scalar& coeffRef(int index)
+    { return m_matrix.const_cast_derived().coeffRef(index); }
+
+  protected:
+    ExpressionTypeNested m_matrix;
+};
+
+template<typename ExpressionType, unsigned int Added, unsigned int Removed>
+  class SparseFlagged<ExpressionType,Added,Removed>::InnerIterator : public ExpressionType::InnerIterator
+{
+  public:
+
+    EIGEN_STRONG_INLINE InnerIterator(const SparseFlagged& xpr, int outer)
+      : ExpressionType::InnerIterator(xpr.m_matrix, outer)
+    {}
+};
+
+template<typename ExpressionType, unsigned int Added, unsigned int Removed>
+  class SparseFlagged<ExpressionType,Added,Removed>::ReverseInnerIterator : public ExpressionType::ReverseInnerIterator
+{
+  public:
+
+    EIGEN_STRONG_INLINE ReverseInnerIterator(const SparseFlagged& xpr, int outer)
+      : ExpressionType::ReverseInnerIterator(xpr.m_matrix, outer)
+    {}
+};
+
+template<typename Derived>
+template<unsigned int Added>
+inline const SparseFlagged<Derived, Added, 0>
+SparseMatrixBase<Derived>::marked() const
+{
+  return derived();
+}
+
+#endif // EIGEN_SPARSE_FLAGGED_H
diff --git a/extern/Eigen2/Eigen/src/Sparse/SparseFuzzy.h b/extern/Eigen2/Eigen/src/Sparse/SparseFuzzy.h
new file mode 100644
index 00000000000..355f4d52eab
--- /dev/null
+++ b/extern/Eigen2/Eigen/src/Sparse/SparseFuzzy.h
@@ -0,0 +1,41 @@
+// 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_SPARSE_FUZZY_H
+#define EIGEN_SPARSE_FUZZY_H
+
+// template<typename Derived>
+// template<typename OtherDerived>
+// bool SparseMatrixBase<Derived>::isApprox(
+//   const OtherDerived& other,
+//   typename NumTraits<Scalar>::Real prec
+// ) const
+// {
+//   const typename ei_nested<Derived,2>::type nested(derived());
+//   const typename ei_nested<OtherDerived,2>::type otherNested(other.derived());
+//   return    (nested - otherNested).cwise().abs2().sum()
+//          <= prec * prec * std::min(nested.cwise().abs2().sum(), otherNested.cwise().abs2().sum());
+// }
+
+#endif // EIGEN_SPARSE_FUZZY_H
diff --git a/extern/Eigen2/Eigen/src/Sparse/SparseLDLT.h b/extern/Eigen2/Eigen/src/Sparse/SparseLDLT.h
new file mode 100644
index 00000000000..a1bac4d084d
--- /dev/null
+++ b/extern/Eigen2/Eigen/src/Sparse/SparseLDLT.h
@@ -0,0 +1,346 @@
+// 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/>.
+
+/*
+
+NOTE: the _symbolic, and _numeric functions has been adapted from
+      the LDL library:
+
+LDL Copyright (c) 2005 by Timothy A. Davis.  All Rights Reserved.
+
+LDL License:
+
+    Your use or distribution of LDL or any modified version of
+    LDL implies that you agree to this License.
+
+    This library 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 2.1 of the License, or (at your option) any later version.
+
+    This library 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 for more details.
+
+    You should have received a copy of the GNU Lesser General Public
+    License along with this library; if not, write to the Free Software
+    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301
+    USA
+
+    Permission is hereby granted to use or copy this program under the
+    terms of the GNU LGPL, provided that the Copyright, this License,
+    and the Availability of the original version is retained on all copies.
+    User documentation of any code that uses this code or any modified
+    version of this code must cite the Copyright, this License, the
+    Availability note, and "Used by permission." Permission to modify
+    the code and to distribute modified code is granted, provided the
+    Copyright, this License, and the Availability note are retained,
+    and a notice that the code was modified is included.
+ */
+
+#ifndef EIGEN_SPARSELDLT_H
+#define EIGEN_SPARSELDLT_H
+
+/** \ingroup Sparse_Module
+  *
+  * \class SparseLDLT
+  *
+  * \brief LDLT Cholesky decomposition of a sparse matrix and associated features
+  *
+  * \param MatrixType the type of the matrix of which we are computing the LDLT Cholesky decomposition
+  *
+  * \sa class LDLT, class LDLT
+  */
+template<typename MatrixType, int Backend = DefaultBackend>
+class SparseLDLT
+{
+  protected:
+    typedef typename MatrixType::Scalar Scalar;
+    typedef typename NumTraits<typename MatrixType::Scalar>::Real RealScalar;
+    typedef SparseMatrix<Scalar,LowerTriangular|UnitDiagBit> CholMatrixType;
+    typedef Matrix<Scalar,MatrixType::ColsAtCompileTime,1> VectorType;
+
+    enum {
+      SupernodalFactorIsDirty      = 0x10000,
+      MatrixLIsDirty               = 0x20000
+    };
+
+  public:
+
+    /** Creates a dummy LDLT factorization object with flags \a flags. */
+    SparseLDLT(int flags = 0)
+      : m_flags(flags), m_status(0)
+    {
+      ei_assert((MatrixType::Flags&RowMajorBit)==0);
+      m_precision = RealScalar(0.1) * Eigen::precision<RealScalar>();
+    }
+
+    /** Creates a LDLT object and compute the respective factorization of \a matrix using
+      * flags \a flags. */
+    SparseLDLT(const MatrixType& matrix, int flags = 0)
+      : m_matrix(matrix.rows(), matrix.cols()), m_flags(flags), m_status(0)
+    {
+      ei_assert((MatrixType::Flags&RowMajorBit)==0);
+      m_precision = RealScalar(0.1) * Eigen::precision<RealScalar>();
+      compute(matrix);
+    }
+
+    /** Sets the relative threshold value used to prune zero coefficients during the decomposition.
+      *
+      * Setting a value greater than zero speeds up computation, and yields to an imcomplete
+      * factorization with fewer non zero coefficients. Such approximate factors are especially
+      * useful to initialize an iterative solver.
+      *
+      * \warning if precision is greater that zero, the LDLT factorization is not guaranteed to succeed
+      * even if the matrix is positive definite.
+      *
+      * Note that the exact meaning of this parameter might depends on the actual
+      * backend. Moreover, not all backends support this feature.
+      *
+      * \sa precision() */
+    void setPrecision(RealScalar v) { m_precision = v; }
+
+    /** \returns the current precision.
+      *
+      * \sa setPrecision() */
+    RealScalar precision() const { return m_precision; }
+
+    /** Sets the flags. Possible values are:
+      *  - CompleteFactorization
+      *  - IncompleteFactorization
+      *  - MemoryEfficient          (hint to use the memory most efficient method offered by the backend)
+      *  - SupernodalMultifrontal   (implies a complete factorization if supported by the backend,
+      *                              overloads the MemoryEfficient flags)
+      *  - SupernodalLeftLooking    (implies a complete factorization  if supported by the backend,
+      *                              overloads the MemoryEfficient flags)
+      *
+      * \sa flags() */
+    void settagss(int f) { m_flags = f; }
+    /** \returns the current flags */
+    int flags() const { return m_flags; }
+
+    /** Computes/re-computes the LDLT factorization */
+    void compute(const MatrixType& matrix);
+
+    /** Perform a symbolic factorization */
+    void _symbolic(const MatrixType& matrix);
+    /** Perform the actual factorization using the previously
+      * computed symbolic factorization */
+    bool _numeric(const MatrixType& matrix);
+
+    /** \returns the lower triangular matrix L */
+    inline const CholMatrixType& matrixL(void) const { return m_matrix; }
+
+    /** \returns the coefficients of the diagonal matrix D */
+    inline VectorType vectorD(void) const { return m_diag; }
+
+    template<typename Derived>
+    bool solveInPlace(MatrixBase<Derived> &b) const;
+
+    /** \returns true if the factorization succeeded */
+    inline bool succeeded(void) const { return m_succeeded; }
+
+  protected:
+    CholMatrixType m_matrix;
+    VectorType m_diag;
+    VectorXi m_parent; // elimination tree
+    VectorXi m_nonZerosPerCol;
+//     VectorXi m_w; // workspace
+    RealScalar m_precision;
+    int m_flags;
+    mutable int m_status;
+    bool m_succeeded;
+};
+
+/** Computes / recomputes the LDLT decomposition of matrix \a a
+  * using the default algorithm.
+  */
+template<typename MatrixType, int Backend>
+void SparseLDLT<MatrixType,Backend>::compute(const MatrixType& a)
+{
+  _symbolic(a);
+  m_succeeded = _numeric(a);
+}
+
+template<typename MatrixType, int Backend>
+void SparseLDLT<MatrixType,Backend>::_symbolic(const MatrixType& a)
+{
+  assert(a.rows()==a.cols());
+  const int size = a.rows();
+  m_matrix.resize(size, size);
+  m_parent.resize(size);
+  m_nonZerosPerCol.resize(size);
+  int * tags = ei_aligned_stack_new(int, size);
+
+  const int* Ap = a._outerIndexPtr();
+  const int* Ai = a._innerIndexPtr();
+  int* Lp = m_matrix._outerIndexPtr();
+  const int* P = 0;
+  int* Pinv = 0;
+
+  if (P)
+  {
+    /* If P is present then compute Pinv, the inverse of P */
+    for (int k = 0; k < size; ++k)
+      Pinv[P[k]] = k;
+  }
+  for (int k = 0; k < size; ++k)
+  {
+    /* L(k,:) pattern: all nodes reachable in etree from nz in A(0:k-1,k) */
+    m_parent[k] = -1;             /* parent of k is not yet known */
+    tags[k] = k;                  /* mark node k as visited */
+    m_nonZerosPerCol[k] = 0;      /* count of nonzeros in column k of L */
+    int kk = P ? P[k] : k;  /* kth original, or permuted, column */
+    int p2 = Ap[kk+1];
+    for (int p = Ap[kk]; p < p2; ++p)
+    {
+      /* A (i,k) is nonzero (original or permuted A) */
+      int i = Pinv ? Pinv[Ai[p]] : Ai[p];
+      if (i < k)
+      {
+        /* follow path from i to root of etree, stop at flagged node */
+        for (; tags[i] != k; i = m_parent[i])
+        {
+          /* find parent of i if not yet determined */
+          if (m_parent[i] == -1)
+            m_parent[i] = k;
+          ++m_nonZerosPerCol[i];        /* L (k,i) is nonzero */
+          tags[i] = k;                  /* mark i as visited */
+        }
+      }
+    }
+  }
+  /* construct Lp index array from m_nonZerosPerCol column counts */
+  Lp[0] = 0;
+  for (int k = 0; k < size; ++k)
+    Lp[k+1] = Lp[k] + m_nonZerosPerCol[k];
+
+  m_matrix.resizeNonZeros(Lp[size]);
+  ei_aligned_stack_delete(int, tags, size);
+}
+
+template<typename MatrixType, int Backend>
+bool SparseLDLT<MatrixType,Backend>::_numeric(const MatrixType& a)
+{
+  assert(a.rows()==a.cols());
+  const int size = a.rows();
+  assert(m_parent.size()==size);
+  assert(m_nonZerosPerCol.size()==size);
+
+  const int* Ap = a._outerIndexPtr();
+  const int* Ai = a._innerIndexPtr();
+  const Scalar* Ax = a._valuePtr();
+  const int* Lp = m_matrix._outerIndexPtr();
+  int* Li = m_matrix._innerIndexPtr();
+  Scalar* Lx = m_matrix._valuePtr();
+  m_diag.resize(size);
+
+  Scalar * y = ei_aligned_stack_new(Scalar, size);
+  int * pattern = ei_aligned_stack_new(int, size);
+  int * tags = ei_aligned_stack_new(int, size);
+
+  const int* P = 0;
+  const int* Pinv = 0;
+  bool ok = true;
+
+  for (int k = 0; k < size; ++k)
+  {
+    /* compute nonzero pattern of kth row of L, in topological order */
+    y[k] = 0.0;                   /* Y(0:k) is now all zero */
+    int top = size;               /* stack for pattern is empty */
+    tags[k] = k;                  /* mark node k as visited */
+    m_nonZerosPerCol[k] = 0;      /* count of nonzeros in column k of L */
+    int kk = (P) ? (P[k]) : (k);  /* kth original, or permuted, column */
+    int p2 = Ap[kk+1];
+    for (int p = Ap[kk]; p < p2; ++p)
+    {
+      int i = Pinv ? Pinv[Ai[p]] : Ai[p]; /* get A(i,k) */
+      if (i <= k)
+      {
+        y[i] += Ax[p];            /* scatter A(i,k) into Y (sum duplicates) */
+        int len;
+        for (len = 0; tags[i] != k; i = m_parent[i])
+        {
+          pattern[len++] = i;     /* L(k,i) is nonzero */
+          tags[i] = k;            /* mark i as visited */
+        }
+        while (len > 0)
+          pattern[--top] = pattern[--len];
+      }
+    }
+    /* compute numerical values kth row of L (a sparse triangular solve) */
+    m_diag[k] = y[k];                       /* get D(k,k) and clear Y(k) */
+    y[k] = 0.0;
+    for (; top < size; ++top)
+    {
+      int i = pattern[top];      /* pattern[top:n-1] is pattern of L(:,k) */
+      Scalar yi = y[i];          /* get and clear Y(i) */
+      y[i] = 0.0;
+      int p2 = Lp[i] + m_nonZerosPerCol[i];
+      int p;
+      for (p = Lp[i]; p < p2; ++p)
+        y[Li[p]] -= Lx[p] * yi;
+      Scalar l_ki = yi / m_diag[i];       /* the nonzero entry L(k,i) */
+      m_diag[k] -= l_ki * yi;
+      Li[p] = k;                          /* store L(k,i) in column form of L */
+      Lx[p] = l_ki;
+      ++m_nonZerosPerCol[i];              /* increment count of nonzeros in col i */
+    }
+    if (m_diag[k] == 0.0)
+    {
+      ok = false;                         /* failure, D(k,k) is zero */
+      break;
+    }
+  }
+
+  ei_aligned_stack_delete(Scalar, y, size);
+  ei_aligned_stack_delete(int, pattern, size);
+  ei_aligned_stack_delete(int, tags, size);
+
+  return ok;  /* success, diagonal of D is all nonzero */
+}
+
+/** Computes b = L^-T L^-1 b */
+template<typename MatrixType, int Backend>
+template<typename Derived>
+bool SparseLDLT<MatrixType, Backend>::solveInPlace(MatrixBase<Derived> &b) const
+{
+  const int size = m_matrix.rows();
+  ei_assert(size==b.rows());
+  if (!m_succeeded)
+    return false;
+
+  if (m_matrix.nonZeros()>0) // otherwise L==I
+    m_matrix.solveTriangularInPlace(b);
+  b = b.cwise() / m_diag;
+  // FIXME should be .adjoint() but it fails to compile...
+
+  if (m_matrix.nonZeros()>0) // otherwise L==I
+  m_matrix.transpose().solveTriangularInPlace(b);
+
+  return true;
+}
+
+#endif // EIGEN_SPARSELDLT_H
diff --git a/extern/Eigen2/Eigen/src/Sparse/SparseLLT.h b/extern/Eigen2/Eigen/src/Sparse/SparseLLT.h
new file mode 100644
index 00000000000..e7c314c2cad
--- /dev/null
+++ b/extern/Eigen2/Eigen/src/Sparse/SparseLLT.h
@@ -0,0 +1,205 @@
+// 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_SPARSELLT_H
+#define EIGEN_SPARSELLT_H
+
+/** \ingroup Sparse_Module
+  *
+  * \class SparseLLT
+  *
+  * \brief LLT Cholesky decomposition of a sparse matrix and associated features
+  *
+  * \param MatrixType the type of the matrix of which we are computing the LLT Cholesky decomposition
+  *
+  * \sa class LLT, class LDLT
+  */
+template<typename MatrixType, int Backend = DefaultBackend>
+class SparseLLT
+{
+  protected:
+    typedef typename MatrixType::Scalar Scalar;
+    typedef typename NumTraits<typename MatrixType::Scalar>::Real RealScalar;
+    typedef SparseMatrix<Scalar,LowerTriangular> CholMatrixType;
+
+    enum {
+      SupernodalFactorIsDirty      = 0x10000,
+      MatrixLIsDirty               = 0x20000
+    };
+
+  public:
+
+    /** Creates a dummy LLT factorization object with flags \a flags. */
+    SparseLLT(int flags = 0)
+      : m_flags(flags), m_status(0)
+    {
+      m_precision = RealScalar(0.1) * Eigen::precision<RealScalar>();
+    }
+
+    /** Creates a LLT object and compute the respective factorization of \a matrix using
+      * flags \a flags. */
+    SparseLLT(const MatrixType& matrix, int flags = 0)
+      : m_matrix(matrix.rows(), matrix.cols()), m_flags(flags), m_status(0)
+    {
+      m_precision = RealScalar(0.1) * Eigen::precision<RealScalar>();
+      compute(matrix);
+    }
+
+    /** Sets the relative threshold value used to prune zero coefficients during the decomposition.
+      *
+      * Setting a value greater than zero speeds up computation, and yields to an imcomplete
+      * factorization with fewer non zero coefficients. Such approximate factors are especially
+      * useful to initialize an iterative solver.
+      *
+      * \warning if precision is greater that zero, the LLT factorization is not guaranteed to succeed
+      * even if the matrix is positive definite.
+      *
+      * Note that the exact meaning of this parameter might depends on the actual
+      * backend. Moreover, not all backends support this feature.
+      *
+      * \sa precision() */
+    void setPrecision(RealScalar v) { m_precision = v; }
+
+    /** \returns the current precision.
+      *
+      * \sa setPrecision() */
+    RealScalar precision() const { return m_precision; }
+
+    /** Sets the flags. Possible values are:
+      *  - CompleteFactorization
+      *  - IncompleteFactorization
+      *  - MemoryEfficient          (hint to use the memory most efficient method offered by the backend)
+      *  - SupernodalMultifrontal   (implies a complete factorization if supported by the backend,
+      *                              overloads the MemoryEfficient flags)
+      *  - SupernodalLeftLooking    (implies a complete factorization  if supported by the backend,
+      *                              overloads the MemoryEfficient flags)
+      *
+      * \sa flags() */
+    void setFlags(int f) { m_flags = f; }
+    /** \returns the current flags */
+    int flags() const { return m_flags; }
+
+    /** Computes/re-computes the LLT factorization */
+    void compute(const MatrixType& matrix);
+
+    /** \returns the lower triangular matrix L */
+    inline const CholMatrixType& matrixL(void) const { return m_matrix; }
+
+    template<typename Derived>
+    bool solveInPlace(MatrixBase<Derived> &b) const;
+
+    /** \returns true if the factorization succeeded */
+    inline bool succeeded(void) const { return m_succeeded; }
+
+  protected:
+    CholMatrixType m_matrix;
+    RealScalar m_precision;
+    int m_flags;
+    mutable int m_status;
+    bool m_succeeded;
+};
+
+/** Computes / recomputes the LLT decomposition of matrix \a a
+  * using the default algorithm.
+  */
+template<typename MatrixType, int Backend>
+void SparseLLT<MatrixType,Backend>::compute(const MatrixType& a)
+{
+  assert(a.rows()==a.cols());
+  const int size = a.rows();
+  m_matrix.resize(size, size);
+
+  // allocate a temporary vector for accumulations
+  AmbiVector<Scalar> tempVector(size);
+  RealScalar density = a.nonZeros()/RealScalar(size*size);
+
+  // TODO estimate the number of non zeros
+  m_matrix.startFill(a.nonZeros()*2);
+  for (int j = 0; j < size; ++j)
+  {
+    Scalar x = ei_real(a.coeff(j,j));
+
+    // TODO better estimate of the density !
+    tempVector.init(density>0.001? IsDense : IsSparse);
+    tempVector.setBounds(j+1,size);
+    tempVector.setZero();
+    // init with current matrix a
+    {
+      typename MatrixType::InnerIterator it(a,j);
+      ++it; // skip diagonal element
+      for (; it; ++it)
+        tempVector.coeffRef(it.index()) = it.value();
+    }
+    for (int k=0; k<j+1; ++k)
+    {
+      typename CholMatrixType::InnerIterator it(m_matrix, k);
+      while (it && it.index()<j)
+        ++it;
+      if (it && it.index()==j)
+      {
+        Scalar y = it.value();
+        x -= ei_abs2(y);
+        ++it; // skip j-th element, and process remaining column coefficients
+        tempVector.restart();
+        for (; it; ++it)
+        {
+          tempVector.coeffRef(it.index()) -= it.value() * y;
+        }
+      }
+    }
+    // copy the temporary vector to the respective m_matrix.col()
+    // while scaling the result by 1/real(x)
+    RealScalar rx = ei_sqrt(ei_real(x));
+    m_matrix.fill(j,j) = rx;
+    Scalar y = Scalar(1)/rx;
+    for (typename AmbiVector<Scalar>::Iterator it(tempVector, m_precision*rx); it; ++it)
+    {
+      m_matrix.fill(it.index(), j) = it.value() * y;
+    }
+  }
+  m_matrix.endFill();
+}
+
+/** Computes b = L^-T L^-1 b */
+template<typename MatrixType, int Backend>
+template<typename Derived>
+bool SparseLLT<MatrixType, Backend>::solveInPlace(MatrixBase<Derived> &b) const
+{
+  const int size = m_matrix.rows();
+  ei_assert(size==b.rows());
+
+  m_matrix.solveTriangularInPlace(b);
+  // FIXME should be simply .adjoint() but it fails to compile...
+  if (NumTraits<Scalar>::IsComplex)
+  {
+    CholMatrixType aux = m_matrix.conjugate();
+    aux.transpose().solveTriangularInPlace(b);
+  }
+  else
+    m_matrix.transpose().solveTriangularInPlace(b);
+
+  return true;
+}
+
+#endif // EIGEN_SPARSELLT_H
diff --git a/extern/Eigen2/Eigen/src/Sparse/SparseLU.h b/extern/Eigen2/Eigen/src/Sparse/SparseLU.h
new file mode 100644
index 00000000000..1425920509f
--- /dev/null
+++ b/extern/Eigen2/Eigen/src/Sparse/SparseLU.h
@@ -0,0 +1,148 @@
+// 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_SPARSELU_H
+#define EIGEN_SPARSELU_H
+
+/** \ingroup Sparse_Module
+  *
+  * \class SparseLU
+  *
+  * \brief LU decomposition of a sparse matrix and associated features
+  *
+  * \param MatrixType the type of the matrix of which we are computing the LU factorization
+  *
+  * \sa class LU, class SparseLLT
+  */
+template<typename MatrixType, int Backend = DefaultBackend>
+class SparseLU
+{
+  protected:
+    typedef typename MatrixType::Scalar Scalar;
+    typedef typename NumTraits<typename MatrixType::Scalar>::Real RealScalar;
+    typedef SparseMatrix<Scalar,LowerTriangular> LUMatrixType;
+
+    enum {
+      MatrixLUIsDirty             = 0x10000
+    };
+
+  public:
+
+    /** Creates a dummy LU factorization object with flags \a flags. */
+    SparseLU(int flags = 0)
+      : m_flags(flags), m_status(0)
+    {
+      m_precision = RealScalar(0.1) * Eigen::precision<RealScalar>();
+    }
+
+    /** Creates a LU object and compute the respective factorization of \a matrix using
+      * flags \a flags. */
+    SparseLU(const MatrixType& matrix, int flags = 0)
+      : /*m_matrix(matrix.rows(), matrix.cols()),*/ m_flags(flags), m_status(0)
+    {
+      m_precision = RealScalar(0.1) * Eigen::precision<RealScalar>();
+      compute(matrix);
+    }
+
+    /** Sets the relative threshold value used to prune zero coefficients during the decomposition.
+      *
+      * Setting a value greater than zero speeds up computation, and yields to an imcomplete
+      * factorization with fewer non zero coefficients. Such approximate factors are especially
+      * useful to initialize an iterative solver.
+      *
+      * Note that the exact meaning of this parameter might depends on the actual
+      * backend. Moreover, not all backends support this feature.
+      *
+      * \sa precision() */
+    void setPrecision(RealScalar v) { m_precision = v; }
+
+    /** \returns the current precision.
+      *
+      * \sa setPrecision() */
+    RealScalar precision() const { return m_precision; }
+
+    /** Sets the flags. Possible values are:
+      *  - CompleteFactorization
+      *  - IncompleteFactorization
+      *  - MemoryEfficient
+      *  - one of the ordering methods
+      *  - etc...
+      *
+      * \sa flags() */
+    void setFlags(int f) { m_flags = f; }
+    /** \returns the current flags */
+    int flags() const { return m_flags; }
+
+    void setOrderingMethod(int m)
+    {
+      ei_assert(m&~OrderingMask == 0 && m!=0 && "invalid ordering method");
+      m_flags = m_flags&~OrderingMask | m&OrderingMask;
+    }
+
+    int orderingMethod() const
+    {
+      return m_flags&OrderingMask;
+    }
+
+    /** Computes/re-computes the LU factorization */
+    void compute(const MatrixType& matrix);
+
+    /** \returns the lower triangular matrix L */
+    //inline const MatrixType& matrixL() const { return m_matrixL; }
+
+    /** \returns the upper triangular matrix U */
+    //inline const MatrixType& matrixU() const { return m_matrixU; }
+
+    template<typename BDerived, typename XDerived>
+    bool solve(const MatrixBase<BDerived> &b, MatrixBase<XDerived>* x) const;
+
+    /** \returns true if the factorization succeeded */
+    inline bool succeeded(void) const { return m_succeeded; }
+
+  protected:
+    RealScalar m_precision;
+    int m_flags;
+    mutable int m_status;
+    bool m_succeeded;
+};
+
+/** Computes / recomputes the LU decomposition of matrix \a a
+  * using the default algorithm.
+  */
+template<typename MatrixType, int Backend>
+void SparseLU<MatrixType,Backend>::compute(const MatrixType& a)
+{
+  ei_assert(false && "not implemented yet");
+}
+
+/** Computes *x = U^-1 L^-1 b */
+template<typename MatrixType, int Backend>
+template<typename BDerived, typename XDerived>
+bool SparseLU<MatrixType,Backend>::solve(const MatrixBase<BDerived> &b, MatrixBase<XDerived>* x) const
+{
+  ei_assert(false && "not implemented yet");
+  return false;
+}
+
+#endif // EIGEN_SPARSELU_H
diff --git a/extern/Eigen2/Eigen/src/Sparse/SparseMatrix.h b/extern/Eigen2/Eigen/src/Sparse/SparseMatrix.h
new file mode 100644
index 00000000000..3f09596bc64
--- /dev/null
+++ b/extern/Eigen2/Eigen/src/Sparse/SparseMatrix.h
@@ -0,0 +1,447 @@
+// This file is part of Eigen, a lightweight C++ template library
+// for linear algebra. Eigen itself is part of the KDE project.
+//
+// Copyright (C) 2008-2009 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_SPARSEMATRIX_H
+#define EIGEN_SPARSEMATRIX_H
+
+/** \class SparseMatrix
+  *
+  * \brief Sparse matrix
+  *
+  * \param _Scalar the scalar type, i.e. the type of the coefficients
+  *
+  * See http://www.netlib.org/linalg/html_templates/node91.html for details on the storage scheme.
+  *
+  */
+template<typename _Scalar, int _Flags>
+struct ei_traits<SparseMatrix<_Scalar, _Flags> >
+{
+  typedef _Scalar Scalar;
+  enum {
+    RowsAtCompileTime = Dynamic,
+    ColsAtCompileTime = Dynamic,
+    MaxRowsAtCompileTime = Dynamic,
+    MaxColsAtCompileTime = Dynamic,
+    Flags = SparseBit | _Flags,
+    CoeffReadCost = NumTraits<Scalar>::ReadCost,
+    SupportedAccessPatterns = InnerRandomAccessPattern
+  };
+};
+
+
+
+template<typename _Scalar, int _Flags>
+class SparseMatrix
+  : public SparseMatrixBase<SparseMatrix<_Scalar, _Flags> >
+{
+  public:
+    EIGEN_SPARSE_GENERIC_PUBLIC_INTERFACE(SparseMatrix)
+    EIGEN_SPARSE_INHERIT_ASSIGNMENT_OPERATOR(SparseMatrix, +=)
+    EIGEN_SPARSE_INHERIT_ASSIGNMENT_OPERATOR(SparseMatrix, -=)
+    // FIXME: why are these operator already alvailable ???
+    // EIGEN_SPARSE_INHERIT_SCALAR_ASSIGNMENT_OPERATOR(SparseMatrix, *=)
+    // EIGEN_SPARSE_INHERIT_SCALAR_ASSIGNMENT_OPERATOR(SparseMatrix, /=)
+
+    typedef MappedSparseMatrix<Scalar,Flags> Map;
+
+  protected:
+
+    enum { IsRowMajor = Base::IsRowMajor };
+    typedef SparseMatrix<Scalar,(Flags&~RowMajorBit)|(IsRowMajor?RowMajorBit:0)> TransposedSparseMatrix;
+
+    int m_outerSize;
+    int m_innerSize;
+    int* m_outerIndex;
+    CompressedStorage<Scalar> m_data;
+
+  public:
+
+    inline int rows() const { return IsRowMajor ? m_outerSize : m_innerSize; }
+    inline int cols() const { return IsRowMajor ? m_innerSize : m_outerSize; }
+
+    inline int innerSize() const { return m_innerSize; }
+    inline int outerSize() const { return m_outerSize; }
+    inline int innerNonZeros(int j) const { return m_outerIndex[j+1]-m_outerIndex[j]; }
+
+    inline const Scalar* _valuePtr() const { return &m_data.value(0); }
+    inline Scalar* _valuePtr() { return &m_data.value(0); }
+
+    inline const int* _innerIndexPtr() const { return &m_data.index(0); }
+    inline int* _innerIndexPtr() { return &m_data.index(0); }
+
+    inline const int* _outerIndexPtr() const { return m_outerIndex; }
+    inline int* _outerIndexPtr() { return m_outerIndex; }
+
+    inline Scalar coeff(int row, int col) const
+    {
+      const int outer = IsRowMajor ? row : col;
+      const int inner = IsRowMajor ? col : row;
+      return m_data.atInRange(m_outerIndex[outer], m_outerIndex[outer+1], inner);
+    }
+
+    inline Scalar& coeffRef(int row, int col)
+    {
+      const int outer = IsRowMajor ? row : col;
+      const int inner = IsRowMajor ? col : row;
+
+      int start = m_outerIndex[outer];
+      int end = m_outerIndex[outer+1];
+      ei_assert(end>=start && "you probably called coeffRef on a non finalized matrix");
+      ei_assert(end>start && "coeffRef cannot be called on a zero coefficient");
+      const int id = m_data.searchLowerIndex(start,end-1,inner);
+      ei_assert((id<end) && (m_data.index(id)==inner) && "coeffRef cannot be called on a zero coefficient");
+      return m_data.value(id);
+    }
+
+  public:
+
+    class InnerIterator;
+
+    inline void setZero()
+    {
+      m_data.clear();
+      //if (m_outerSize)
+      memset(m_outerIndex, 0, (m_outerSize+1)*sizeof(int));
+//       for (int i=0; i<m_outerSize; ++i)
+//         m_outerIndex[i] = 0;
+//       if (m_outerSize)
+//         m_outerIndex[i] = 0;
+    }
+
+    /** \returns the number of non zero coefficients */
+    inline int nonZeros() const  { return m_data.size(); }
+
+    /** Initializes the filling process of \c *this.
+      * \param reserveSize approximate number of nonzeros
+      * Note that the matrix \c *this is zero-ed.
+      */
+    inline void startFill(int reserveSize = 1000)
+    {
+      setZero();
+      m_data.reserve(reserveSize);
+    }
+
+    /**
+      */
+    inline Scalar& fill(int row, int col)
+    {
+      const int outer = IsRowMajor ? row : col;
+      const int inner = IsRowMajor ? col : row;
+
+      if (m_outerIndex[outer+1]==0)
+      {
+        // we start a new inner vector
+        int i = outer;
+        while (i>=0 && m_outerIndex[i]==0)
+        {
+          m_outerIndex[i] = m_data.size();
+          --i;
+        }
+        m_outerIndex[outer+1] = m_outerIndex[outer];
+      }
+      else
+      {
+        ei_assert(m_data.index(m_data.size()-1)<inner && "wrong sorted insertion");
+      }
+      assert(size_t(m_outerIndex[outer+1]) == m_data.size());
+      int id = m_outerIndex[outer+1];
+      ++m_outerIndex[outer+1];
+
+      m_data.append(0, inner);
+      return m_data.value(id);
+    }
+
+    /** Like fill() but with random inner coordinates.
+      */
+    inline Scalar& fillrand(int row, int col)
+    {
+      const int outer = IsRowMajor ? row : col;
+      const int inner = IsRowMajor ? col : row;
+      if (m_outerIndex[outer+1]==0)
+      {
+        // we start a new inner vector
+        // nothing special to do here
+        int i = outer;
+        while (i>=0 && m_outerIndex[i]==0)
+        {
+          m_outerIndex[i] = m_data.size();
+          --i;
+        }
+        m_outerIndex[outer+1] = m_outerIndex[outer];
+      }
+      assert(size_t(m_outerIndex[outer+1]) == m_data.size() && "invalid outer index");
+      size_t startId = m_outerIndex[outer];
+      // FIXME let's make sure sizeof(long int) == sizeof(size_t)
+      size_t id = m_outerIndex[outer+1];
+      ++m_outerIndex[outer+1];
+
+      float reallocRatio = 1;
+      if (m_data.allocatedSize()<id+1)
+      {
+        // we need to reallocate the data, to reduce multiple reallocations
+        // we use a smart resize algorithm based on the current filling ratio
+        // we use float to avoid overflows
+        float nnzEstimate = float(m_outerIndex[outer])*float(m_outerSize)/float(outer);
+        reallocRatio = (nnzEstimate-float(m_data.size()))/float(m_data.size());
+        // let's bounds the realloc ratio to
+        //   1) reduce multiple minor realloc when the matrix is almost filled
+        //   2) avoid to allocate too much memory when the matrix is almost empty
+        reallocRatio = std::min(std::max(reallocRatio,1.5f),8.f);
+      }
+      m_data.resize(id+1,reallocRatio);
+
+      while ( (id > startId) && (m_data.index(id-1) > inner) )
+      {
+        m_data.index(id) = m_data.index(id-1);
+        m_data.value(id) = m_data.value(id-1);
+        --id;
+      }
+
+      m_data.index(id) = inner;
+      return (m_data.value(id) = 0);
+    }
+
+    inline void endFill()
+    {
+      int size = m_data.size();
+      int i = m_outerSize;
+      // find the last filled column
+      while (i>=0 && m_outerIndex[i]==0)
+        --i;
+      ++i;
+      while (i<=m_outerSize)
+      {
+        m_outerIndex[i] = size;
+        ++i;
+      }
+    }
+
+    void prune(Scalar reference, RealScalar epsilon = precision<RealScalar>())
+    {
+      int k = 0;
+      for (int j=0; j<m_outerSize; ++j)
+      {
+        int previousStart = m_outerIndex[j];
+        m_outerIndex[j] = k;
+        int end = m_outerIndex[j+1];
+        for (int i=previousStart; i<end; ++i)
+        {
+          if (!ei_isMuchSmallerThan(m_data.value(i), reference, epsilon))
+          {
+            m_data.value(k) = m_data.value(i);
+            m_data.index(k) = m_data.index(i);
+            ++k;
+          }
+        }
+      }
+      m_outerIndex[m_outerSize] = k;
+      m_data.resize(k,0);
+    }
+
+    void resize(int rows, int cols)
+    {
+//       std::cerr << this << " resize " << rows << "x" << cols << "\n";
+      const int outerSize = IsRowMajor ? rows : cols;
+      m_innerSize = IsRowMajor ? cols : rows;
+      m_data.clear();
+      if (m_outerSize != outerSize)
+      {
+        delete[] m_outerIndex;
+        m_outerIndex = new int [outerSize+1];
+        m_outerSize = outerSize;
+        memset(m_outerIndex, 0, (m_outerSize+1)*sizeof(int));
+      }
+    }
+    void resizeNonZeros(int size)
+    {
+      m_data.resize(size);
+    }
+
+    inline SparseMatrix()
+      : m_outerSize(-1), m_innerSize(0), m_outerIndex(0)
+    {
+      resize(0, 0);
+    }
+
+    inline SparseMatrix(int rows, int cols)
+      : m_outerSize(0), m_innerSize(0), m_outerIndex(0)
+    {
+      resize(rows, cols);
+    }
+
+    template<typename OtherDerived>
+    inline SparseMatrix(const SparseMatrixBase<OtherDerived>& other)
+      : m_outerSize(0), m_innerSize(0), m_outerIndex(0)
+    {
+      *this = other.derived();
+    }
+
+    inline SparseMatrix(const SparseMatrix& other)
+      : Base(), m_outerSize(0), m_innerSize(0), m_outerIndex(0)
+    {
+      *this = other.derived();
+    }
+
+    inline void swap(SparseMatrix& other)
+    {
+      //EIGEN_DBG_SPARSE(std::cout << "SparseMatrix:: swap\n");
+      std::swap(m_outerIndex, other.m_outerIndex);
+      std::swap(m_innerSize, other.m_innerSize);
+      std::swap(m_outerSize, other.m_outerSize);
+      m_data.swap(other.m_data);
+    }
+
+    inline SparseMatrix& operator=(const SparseMatrix& other)
+    {
+//       std::cout << "SparseMatrix& operator=(const SparseMatrix& other)\n";
+      if (other.isRValue())
+      {
+        swap(other.const_cast_derived());
+      }
+      else
+      {
+        resize(other.rows(), other.cols());
+        memcpy(m_outerIndex, other.m_outerIndex, (m_outerSize+1)*sizeof(int));
+        m_data = other.m_data;
+      }
+      return *this;
+    }
+
+    template<typename OtherDerived>
+    inline SparseMatrix& operator=(const SparseMatrixBase<OtherDerived>& other)
+    {
+      const bool needToTranspose = (Flags & RowMajorBit) != (OtherDerived::Flags & RowMajorBit);
+      if (needToTranspose)
+      {
+        // two passes algorithm:
+        //  1 - compute the number of coeffs per dest inner vector
+        //  2 - do the actual copy/eval
+        // Since each coeff of the rhs has to be evaluated twice, let's evauluate it if needed
+        //typedef typename ei_nested<OtherDerived,2>::type OtherCopy;
+        typedef typename ei_eval<OtherDerived>::type OtherCopy;
+        typedef typename ei_cleantype<OtherCopy>::type _OtherCopy;
+        OtherCopy otherCopy(other.derived());
+
+        resize(other.rows(), other.cols());
+        Eigen::Map<VectorXi>(m_outerIndex,outerSize()).setZero();
+        // pass 1
+        // FIXME the above copy could be merged with that pass
+        for (int j=0; j<otherCopy.outerSize(); ++j)
+          for (typename _OtherCopy::InnerIterator it(otherCopy, j); it; ++it)
+            ++m_outerIndex[it.index()];
+
+        // prefix sum
+        int count = 0;
+        VectorXi positions(outerSize());
+        for (int j=0; j<outerSize(); ++j)
+        {
+          int tmp = m_outerIndex[j];
+          m_outerIndex[j] = count;
+          positions[j] = count;
+          count += tmp;
+        }
+        m_outerIndex[outerSize()] = count;
+        // alloc
+        m_data.resize(count);
+        // pass 2
+        for (int j=0; j<otherCopy.outerSize(); ++j)
+          for (typename _OtherCopy::InnerIterator it(otherCopy, j); it; ++it)
+          {
+            int pos = positions[it.index()]++;
+            m_data.index(pos) = j;
+            m_data.value(pos) = it.value();
+          }
+
+        return *this;
+      }
+      else
+      {
+        // there is no special optimization
+        return SparseMatrixBase<SparseMatrix>::operator=(other.derived());
+      }
+    }
+
+    friend std::ostream & operator << (std::ostream & s, const SparseMatrix& m)
+    {
+      EIGEN_DBG_SPARSE(
+        s << "Nonzero entries:\n";
+        for (int i=0; i<m.nonZeros(); ++i)
+        {
+          s << "(" << m.m_data.value(i) << "," << m.m_data.index(i) << ") ";
+        }
+        s << std::endl;
+        s << std::endl;
+        s << "Column pointers:\n";
+        for (int i=0; i<m.outerSize(); ++i)
+        {
+          s << m.m_outerIndex[i] << " ";
+        }
+        s << " $" << std::endl;
+        s << std::endl;
+      );
+      s << static_cast<const SparseMatrixBase<SparseMatrix>&>(m);
+      return s;
+    }
+
+    /** Destructor */
+    inline ~SparseMatrix()
+    {
+      delete[] m_outerIndex;
+    }
+};
+
+template<typename Scalar, int _Flags>
+class SparseMatrix<Scalar,_Flags>::InnerIterator
+{
+  public:
+    InnerIterator(const SparseMatrix& mat, int outer)
+      : m_matrix(mat), m_outer(outer), m_id(mat.m_outerIndex[outer]), m_start(m_id), m_end(mat.m_outerIndex[outer+1])
+    {}
+
+    template<unsigned int Added, unsigned int Removed>
+    InnerIterator(const Flagged<SparseMatrix,Added,Removed>& mat, int outer)
+      : m_matrix(mat._expression()), m_outer(outer), m_id(m_matrix.m_outerIndex[outer]),
+        m_start(m_id), m_end(m_matrix.m_outerIndex[outer+1])
+    {}
+
+    inline InnerIterator& operator++() { m_id++; return *this; }
+
+    inline Scalar value() const { return m_matrix.m_data.value(m_id); }
+    inline Scalar& valueRef() { return const_cast<Scalar&>(m_matrix.m_data.value(m_id)); }
+
+    inline int index() const { return m_matrix.m_data.index(m_id); }
+    inline int row() const { return IsRowMajor ? m_outer : index(); }
+    inline int col() const { return IsRowMajor ? index() : m_outer; }
+
+    inline operator bool() const { return (m_id < m_end) && (m_id>=m_start); }
+
+  protected:
+    const SparseMatrix& m_matrix;
+    const int m_outer;
+    int m_id;
+    const int m_start;
+    const int m_end;
+};
+
+#endif // EIGEN_SPARSEMATRIX_H
diff --git a/extern/Eigen2/Eigen/src/Sparse/SparseMatrixBase.h b/extern/Eigen2/Eigen/src/Sparse/SparseMatrixBase.h
new file mode 100644
index 00000000000..468bc9e227c
--- /dev/null
+++ b/extern/Eigen2/Eigen/src/Sparse/SparseMatrixBase.h
@@ -0,0 +1,626 @@
+// 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_SPARSEMATRIXBASE_H
+#define EIGEN_SPARSEMATRIXBASE_H
+
+template<typename Derived> class SparseMatrixBase
+{
+  public:
+
+    typedef typename ei_traits<Derived>::Scalar Scalar;
+//     typedef typename Derived::InnerIterator InnerIterator;
+
+    enum {
+
+      RowsAtCompileTime = ei_traits<Derived>::RowsAtCompileTime,
+        /**< The number of rows at compile-time. This is just a copy of the value provided
+          * by the \a Derived type. If a value is not known at compile-time,
+          * it is set to the \a Dynamic constant.
+          * \sa MatrixBase::rows(), MatrixBase::cols(), ColsAtCompileTime, SizeAtCompileTime */
+
+      ColsAtCompileTime = ei_traits<Derived>::ColsAtCompileTime,
+        /**< The number of columns at compile-time. This is just a copy of the value provided
+          * by the \a Derived type. If a value is not known at compile-time,
+          * it is set to the \a Dynamic constant.
+          * \sa MatrixBase::rows(), MatrixBase::cols(), RowsAtCompileTime, SizeAtCompileTime */
+
+
+      SizeAtCompileTime = (ei_size_at_compile_time<ei_traits<Derived>::RowsAtCompileTime,
+                                                   ei_traits<Derived>::ColsAtCompileTime>::ret),
+        /**< This is equal to the number of coefficients, i.e. the number of
+          * rows times the number of columns, or to \a Dynamic if this is not
+          * known at compile-time. \sa RowsAtCompileTime, ColsAtCompileTime */
+
+      MaxRowsAtCompileTime = RowsAtCompileTime,
+      MaxColsAtCompileTime = ColsAtCompileTime,
+
+      MaxSizeAtCompileTime = (ei_size_at_compile_time<MaxRowsAtCompileTime,
+                                                      MaxColsAtCompileTime>::ret),
+
+      IsVectorAtCompileTime = RowsAtCompileTime == 1 || ColsAtCompileTime == 1,
+        /**< This is set to true if either the number of rows or the number of
+          * columns is known at compile-time to be equal to 1. Indeed, in that case,
+          * we are dealing with a column-vector (if there is only one column) or with
+          * a row-vector (if there is only one row). */
+
+      Flags = ei_traits<Derived>::Flags,
+        /**< This stores expression \ref flags flags which may or may not be inherited by new expressions
+          * constructed from this one. See the \ref flags "list of flags".
+          */
+      
+      CoeffReadCost = ei_traits<Derived>::CoeffReadCost,
+        /**< This is a rough measure of how expensive it is to read one coefficient from
+          * this expression.
+          */
+
+      IsRowMajor = Flags&RowMajorBit ? 1 : 0
+    };
+
+    /** \internal the return type of MatrixBase::conjugate() */
+    typedef typename ei_meta_if<NumTraits<Scalar>::IsComplex,
+                        const SparseCwiseUnaryOp<ei_scalar_conjugate_op<Scalar>, Derived>,
+                        const Derived&
+                     >::ret ConjugateReturnType;
+    /** \internal the return type of MatrixBase::real() */
+    typedef CwiseUnaryOp<ei_scalar_real_op<Scalar>, Derived> RealReturnType;
+    /** \internal the return type of MatrixBase::imag() */
+    typedef CwiseUnaryOp<ei_scalar_imag_op<Scalar>, Derived> ImagReturnType;
+    /** \internal the return type of MatrixBase::adjoint() */
+    typedef SparseTranspose</*NestByValue<*/typename ei_cleantype<ConjugateReturnType>::type> /*>*/
+            AdjointReturnType;
+
+#ifndef EIGEN_PARSED_BY_DOXYGEN
+    /** This is the "real scalar" type; if the \a Scalar type is already real numbers
+      * (e.g. int, float or double) then \a RealScalar is just the same as \a Scalar. If
+      * \a Scalar is \a std::complex<T> then RealScalar is \a T.
+      *
+      * \sa class NumTraits
+      */
+    typedef typename NumTraits<Scalar>::Real RealScalar;
+
+    /** type of the equivalent square matrix */
+    typedef Matrix<Scalar,EIGEN_ENUM_MAX(RowsAtCompileTime,ColsAtCompileTime),
+                          EIGEN_ENUM_MAX(RowsAtCompileTime,ColsAtCompileTime)> SquareMatrixType;
+
+    inline const Derived& derived() const { return *static_cast<const Derived*>(this); }
+    inline Derived& derived() { return *static_cast<Derived*>(this); }
+    inline Derived& const_cast_derived() const
+    { return *static_cast<Derived*>(const_cast<SparseMatrixBase*>(this)); }
+#endif // not EIGEN_PARSED_BY_DOXYGEN
+
+    /** \returns the number of rows. \sa cols(), RowsAtCompileTime */
+    inline int rows() const { return derived().rows(); }
+    /** \returns the number of columns. \sa rows(), ColsAtCompileTime*/
+    inline int cols() const { return derived().cols(); }
+    /** \returns the number of coefficients, which is \a rows()*cols().
+      * \sa rows(), cols(), SizeAtCompileTime. */
+    inline int size() const { return rows() * cols(); }
+    /** \returns the number of nonzero coefficients which is in practice the number
+      * of stored coefficients. */
+    inline int nonZeros() const { return derived().nonZeros(); }
+    /** \returns true if either the number of rows or the number of columns is equal to 1.
+      * In other words, this function returns
+      * \code rows()==1 || cols()==1 \endcode
+      * \sa rows(), cols(), IsVectorAtCompileTime. */
+    inline bool isVector() const { return rows()==1 || cols()==1; }
+    /** \returns the size of the storage major dimension,
+      * i.e., the number of columns for a columns major matrix, and the number of rows otherwise */
+    int outerSize() const { return (int(Flags)&RowMajorBit) ? this->rows() : this->cols(); }
+    /** \returns the size of the inner dimension according to the storage order,
+      * i.e., the number of rows for a columns major matrix, and the number of cols otherwise */
+    int innerSize() const { return (int(Flags)&RowMajorBit) ? this->cols() : this->rows(); }
+
+    bool isRValue() const { return m_isRValue; }
+    Derived& markAsRValue() { m_isRValue = true; return derived(); }
+
+    SparseMatrixBase() : m_isRValue(false) { /* TODO check flags */ }
+
+    inline Derived& operator=(const Derived& other)
+    {
+//       std::cout << "Derived& operator=(const Derived& other)\n";
+//       if (other.isRValue())
+//         derived().swap(other.const_cast_derived());
+//       else
+        this->operator=<Derived>(other);
+      return derived();
+    }
+
+
+    template<typename OtherDerived>
+    inline void assignGeneric(const OtherDerived& other)
+    {
+//       std::cout << "Derived& operator=(const MatrixBase<OtherDerived>& other)\n";
+      //const bool transpose = (Flags & RowMajorBit) != (OtherDerived::Flags & RowMajorBit);
+      ei_assert(( ((ei_traits<Derived>::SupportedAccessPatterns&OuterRandomAccessPattern)==OuterRandomAccessPattern) ||
+                  (!((Flags & RowMajorBit) != (OtherDerived::Flags & RowMajorBit)))) &&
+                  "the transpose operation is supposed to be handled in SparseMatrix::operator=");
+
+      const int outerSize = other.outerSize();
+      //typedef typename ei_meta_if<transpose, LinkedVectorMatrix<Scalar,Flags&RowMajorBit>, Derived>::ret TempType;
+      // thanks to shallow copies, we always eval to a tempary
+      Derived temp(other.rows(), other.cols());
+
+      temp.startFill(std::max(this->rows(),this->cols())*2);
+      for (int j=0; j<outerSize; ++j)
+      {
+        for (typename OtherDerived::InnerIterator it(other.derived(), j); it; ++it)
+        {
+          Scalar v = it.value();
+          if (v!=Scalar(0))
+          {
+            if (OtherDerived::Flags & RowMajorBit) temp.fill(j,it.index()) = v;
+            else temp.fill(it.index(),j) = v;
+          }
+        }
+      }
+      temp.endFill();
+
+      derived() = temp.markAsRValue();
+    }
+
+
+    template<typename OtherDerived>
+    inline Derived& operator=(const SparseMatrixBase<OtherDerived>& other)
+    {
+//       std::cout << typeid(OtherDerived).name() << "\n";
+//       std::cout << Flags << " " << OtherDerived::Flags << "\n";
+      const bool transpose = (Flags & RowMajorBit) != (OtherDerived::Flags & RowMajorBit);
+//       std::cout << "eval transpose = " << transpose << "\n";
+      const int outerSize = (int(OtherDerived::Flags) & RowMajorBit) ? other.rows() : other.cols();
+      if ((!transpose) && other.isRValue())
+      {
+        // eval without temporary
+        derived().resize(other.rows(), other.cols());
+        derived().startFill(std::max(this->rows(),this->cols())*2);
+        for (int j=0; j<outerSize; ++j)
+        {
+          for (typename OtherDerived::InnerIterator it(other.derived(), j); it; ++it)
+          {
+            Scalar v = it.value();
+            if (v!=Scalar(0))
+            {
+              if (IsRowMajor) derived().fill(j,it.index()) = v;
+              else derived().fill(it.index(),j) = v;
+            }
+          }
+        }
+        derived().endFill();
+      }
+      else
+      {
+        assignGeneric(other.derived());
+      }
+      return derived();
+    }
+
+    template<typename Lhs, typename Rhs>
+    inline Derived& operator=(const SparseProduct<Lhs,Rhs,SparseTimeSparseProduct>& product);
+
+    friend std::ostream & operator << (std::ostream & s, const SparseMatrixBase& m)
+    {
+      if (Flags&RowMajorBit)
+      {
+        for (int row=0; row<m.outerSize(); ++row)
+        {
+          int col = 0;
+          for (typename Derived::InnerIterator it(m.derived(), row); it; ++it)
+          {
+            for ( ; col<it.index(); ++col)
+              s << "0 ";
+            s << it.value() << " ";
+            ++col;
+          }
+          for ( ; col<m.cols(); ++col)
+            s << "0 ";
+          s << std::endl;
+        }
+      }
+      else
+      {
+        if (m.cols() == 1) {
+          int row = 0;
+          for (typename Derived::InnerIterator it(m.derived(), 0); it; ++it)
+          {
+            for ( ; row<it.index(); ++row)
+              s << "0" << std::endl;
+            s << it.value() << std::endl;
+            ++row;
+          }
+          for ( ; row<m.rows(); ++row)
+            s << "0" << std::endl;
+        }
+        else
+        {
+          SparseMatrix<Scalar, RowMajorBit> trans = m.derived();
+          s << trans;
+        }
+      }
+      return s;
+    }
+
+    const SparseCwiseUnaryOp<ei_scalar_opposite_op<typename ei_traits<Derived>::Scalar>,Derived> operator-() const;
+
+    template<typename OtherDerived>
+    const SparseCwiseBinaryOp<ei_scalar_sum_op<typename ei_traits<Derived>::Scalar>, Derived, OtherDerived>
+    operator+(const SparseMatrixBase<OtherDerived> &other) const;
+
+    template<typename OtherDerived>
+    const SparseCwiseBinaryOp<ei_scalar_difference_op<typename ei_traits<Derived>::Scalar>, Derived, OtherDerived>
+    operator-(const SparseMatrixBase<OtherDerived> &other) const;
+
+    template<typename OtherDerived>
+    Derived& operator+=(const SparseMatrixBase<OtherDerived>& other);
+    template<typename OtherDerived>
+    Derived& operator-=(const SparseMatrixBase<OtherDerived>& other);
+
+//     template<typename Lhs,typename Rhs>
+//     Derived& operator+=(const Flagged<Product<Lhs,Rhs,CacheFriendlyProduct>, 0, EvalBeforeNestingBit | EvalBeforeAssigningBit>& other);
+
+    Derived& operator*=(const Scalar& other);
+    Derived& operator/=(const Scalar& other);
+
+    const SparseCwiseUnaryOp<ei_scalar_multiple_op<typename ei_traits<Derived>::Scalar>, Derived>
+    operator*(const Scalar& scalar) const;
+    const SparseCwiseUnaryOp<ei_scalar_quotient1_op<typename ei_traits<Derived>::Scalar>, Derived>
+    operator/(const Scalar& scalar) const;
+
+    inline friend const SparseCwiseUnaryOp<ei_scalar_multiple_op<typename ei_traits<Derived>::Scalar>, Derived>
+    operator*(const Scalar& scalar, const SparseMatrixBase& matrix)
+    { return matrix*scalar; }
+
+
+    template<typename OtherDerived>
+    const typename SparseProductReturnType<Derived,OtherDerived>::Type
+    operator*(const SparseMatrixBase<OtherDerived> &other) const;
+    
+    // dense * sparse (return a dense object)
+    template<typename OtherDerived> friend 
+    const typename SparseProductReturnType<OtherDerived,Derived>::Type
+    operator*(const MatrixBase<OtherDerived>& lhs, const Derived& rhs)
+    { return typename SparseProductReturnType<OtherDerived,Derived>::Type(lhs.derived(),rhs); }
+    
+    template<typename OtherDerived>
+    const typename SparseProductReturnType<Derived,OtherDerived>::Type
+    operator*(const MatrixBase<OtherDerived> &other) const;
+
+    template<typename OtherDerived>
+    Derived& operator*=(const SparseMatrixBase<OtherDerived>& other);
+
+    template<typename OtherDerived>
+    typename ei_plain_matrix_type_column_major<OtherDerived>::type
+    solveTriangular(const MatrixBase<OtherDerived>& other) const;
+
+    template<typename OtherDerived>
+    void solveTriangularInPlace(MatrixBase<OtherDerived>& other) const;
+
+    template<typename OtherDerived> Scalar dot(const MatrixBase<OtherDerived>& other) const;
+    template<typename OtherDerived> Scalar dot(const SparseMatrixBase<OtherDerived>& other) const;
+    RealScalar squaredNorm() const;
+    RealScalar norm()  const;
+//     const PlainMatrixType normalized() const;
+//     void normalize();
+
+    SparseTranspose<Derived> transpose() { return derived(); }
+    const SparseTranspose<Derived> transpose() const { return derived(); }
+    // void transposeInPlace();
+    const AdjointReturnType adjoint() const { return conjugate()/*.nestByValue()*/; }
+
+    // sub-vector
+    SparseInnerVectorSet<Derived,1> row(int i);
+    const SparseInnerVectorSet<Derived,1> row(int i) const;
+    SparseInnerVectorSet<Derived,1> col(int j);
+    const SparseInnerVectorSet<Derived,1> col(int j) const;
+    SparseInnerVectorSet<Derived,1> innerVector(int outer);
+    const SparseInnerVectorSet<Derived,1> innerVector(int outer) const;
+    
+    // set of sub-vectors
+    SparseInnerVectorSet<Derived,Dynamic> subrows(int start, int size);
+    const SparseInnerVectorSet<Derived,Dynamic> subrows(int start, int size) const;
+    SparseInnerVectorSet<Derived,Dynamic> subcols(int start, int size);
+    const SparseInnerVectorSet<Derived,Dynamic> subcols(int start, int size) const;
+    SparseInnerVectorSet<Derived,Dynamic> innerVectors(int outerStart, int outerSize);
+    const SparseInnerVectorSet<Derived,Dynamic> innerVectors(int outerStart, int outerSize) const;
+
+//     typename BlockReturnType<Derived>::Type block(int startRow, int startCol, int blockRows, int blockCols);
+//     const typename BlockReturnType<Derived>::Type
+//     block(int startRow, int startCol, int blockRows, int blockCols) const;
+//
+//     typename BlockReturnType<Derived>::SubVectorType segment(int start, int size);
+//     const typename BlockReturnType<Derived>::SubVectorType segment(int start, int size) const;
+//
+//     typename BlockReturnType<Derived,Dynamic>::SubVectorType start(int size);
+//     const typename BlockReturnType<Derived,Dynamic>::SubVectorType start(int size) const;
+//
+//     typename BlockReturnType<Derived,Dynamic>::SubVectorType end(int size);
+//     const typename BlockReturnType<Derived,Dynamic>::SubVectorType end(int size) const;
+//
+//     typename BlockReturnType<Derived>::Type corner(CornerType type, int cRows, int cCols);
+//     const typename BlockReturnType<Derived>::Type corner(CornerType type, int cRows, int cCols) const;
+//
+//     template<int BlockRows, int BlockCols>
+//     typename BlockReturnType<Derived, BlockRows, BlockCols>::Type block(int startRow, int startCol);
+//     template<int BlockRows, int BlockCols>
+//     const typename BlockReturnType<Derived, BlockRows, BlockCols>::Type block(int startRow, int startCol) const;
+
+//     template<int CRows, int CCols>
+//     typename BlockReturnType<Derived, CRows, CCols>::Type corner(CornerType type);
+//     template<int CRows, int CCols>
+//     const typename BlockReturnType<Derived, CRows, CCols>::Type corner(CornerType type) const;
+
+//     template<int Size> typename BlockReturnType<Derived,Size>::SubVectorType start(void);
+//     template<int Size> const typename BlockReturnType<Derived,Size>::SubVectorType start() const;
+
+//     template<int Size> typename BlockReturnType<Derived,Size>::SubVectorType end();
+//     template<int Size> const typename BlockReturnType<Derived,Size>::SubVectorType end() const;
+
+//     template<int Size> typename BlockReturnType<Derived,Size>::SubVectorType segment(int start);
+//     template<int Size> const typename BlockReturnType<Derived,Size>::SubVectorType segment(int start) const;
+
+//     DiagonalCoeffs<Derived> diagonal();
+//     const DiagonalCoeffs<Derived> diagonal() const;
+
+//     template<unsigned int Mode> Part<Derived, Mode> part();
+//     template<unsigned int Mode> const Part<Derived, Mode> part() const;
+
+
+//     static const ConstantReturnType Constant(int rows, int cols, const Scalar& value);
+//     static const ConstantReturnType Constant(int size, const Scalar& value);
+//     static const ConstantReturnType Constant(const Scalar& value);
+
+//     template<typename CustomNullaryOp>
+//     static const CwiseNullaryOp<CustomNullaryOp, Derived> NullaryExpr(int rows, int cols, const CustomNullaryOp& func);
+//     template<typename CustomNullaryOp>
+//     static const CwiseNullaryOp<CustomNullaryOp, Derived> NullaryExpr(int size, const CustomNullaryOp& func);
+//     template<typename CustomNullaryOp>
+//     static const CwiseNullaryOp<CustomNullaryOp, Derived> NullaryExpr(const CustomNullaryOp& func);
+
+//     static const ConstantReturnType Zero(int rows, int cols);
+//     static const ConstantReturnType Zero(int size);
+//     static const ConstantReturnType Zero();
+//     static const ConstantReturnType Ones(int rows, int cols);
+//     static const ConstantReturnType Ones(int size);
+//     static const ConstantReturnType Ones();
+//     static const IdentityReturnType Identity();
+//     static const IdentityReturnType Identity(int rows, int cols);
+//     static const BasisReturnType Unit(int size, int i);
+//     static const BasisReturnType Unit(int i);
+//     static const BasisReturnType UnitX();
+//     static const BasisReturnType UnitY();
+//     static const BasisReturnType UnitZ();
+//     static const BasisReturnType UnitW();
+
+//     const DiagonalMatrix<Derived> asDiagonal() const;
+
+//     Derived& setConstant(const Scalar& value);
+//     Derived& setZero();
+//     Derived& setOnes();
+//     Derived& setRandom();
+//     Derived& setIdentity();
+
+      Matrix<Scalar,RowsAtCompileTime,ColsAtCompileTime> toDense() const
+      {
+        Matrix<Scalar,RowsAtCompileTime,ColsAtCompileTime> res(rows(),cols());
+        res.setZero();
+        for (int j=0; j<outerSize(); ++j)
+        {
+          for (typename Derived::InnerIterator i(derived(),j); i; ++i)
+            if(IsRowMajor)
+              res.coeffRef(j,i.index()) = i.value();
+            else
+              res.coeffRef(i.index(),j) = i.value();
+        }
+        return res;
+      }
+
+    template<typename OtherDerived>
+    bool isApprox(const SparseMatrixBase<OtherDerived>& other,
+                  RealScalar prec = precision<Scalar>()) const
+    { return toDense().isApprox(other.toDense(),prec); }
+
+    template<typename OtherDerived>
+    bool isApprox(const MatrixBase<OtherDerived>& other,
+                  RealScalar prec = precision<Scalar>()) const
+    { return toDense().isApprox(other,prec); }
+//     bool isMuchSmallerThan(const RealScalar& other,
+//                            RealScalar prec = precision<Scalar>()) const;
+//     template<typename OtherDerived>
+//     bool isMuchSmallerThan(const MatrixBase<OtherDerived>& other,
+//                            RealScalar prec = precision<Scalar>()) const;
+
+//     bool isApproxToConstant(const Scalar& value, RealScalar prec = precision<Scalar>()) const;
+//     bool isZero(RealScalar prec = precision<Scalar>()) const;
+//     bool isOnes(RealScalar prec = precision<Scalar>()) const;
+//     bool isIdentity(RealScalar prec = precision<Scalar>()) const;
+//     bool isDiagonal(RealScalar prec = precision<Scalar>()) const;
+
+//     bool isUpperTriangular(RealScalar prec = precision<Scalar>()) const;
+//     bool isLowerTriangular(RealScalar prec = precision<Scalar>()) const;
+
+//     template<typename OtherDerived>
+//     bool isOrthogonal(const MatrixBase<OtherDerived>& other,
+//                       RealScalar prec = precision<Scalar>()) const;
+//     bool isUnitary(RealScalar prec = precision<Scalar>()) const;
+
+//     template<typename OtherDerived>
+//     inline bool operator==(const MatrixBase<OtherDerived>& other) const
+//     { return (cwise() == other).all(); }
+
+//     template<typename OtherDerived>
+//     inline bool operator!=(const MatrixBase<OtherDerived>& other) const
+//     { return (cwise() != other).any(); }
+
+
+    template<typename NewType>
+    const SparseCwiseUnaryOp<ei_scalar_cast_op<typename ei_traits<Derived>::Scalar, NewType>, Derived> cast() const;
+
+    /** \returns the matrix or vector obtained by evaluating this expression.
+      *
+      * Notice that in the case of a plain matrix or vector (not an expression) this function just returns
+      * a const reference, in order to avoid a useless copy.
+      */
+    EIGEN_STRONG_INLINE const typename ei_eval<Derived>::type eval() const
+    { return typename ei_eval<Derived>::type(derived()); }
+
+//     template<typename OtherDerived>
+//     void swap(const MatrixBase<OtherDerived>& other);
+
+    template<unsigned int Added>
+    const SparseFlagged<Derived, Added, 0> marked() const;
+//     const Flagged<Derived, 0, EvalBeforeNestingBit | EvalBeforeAssigningBit> lazy() const;
+
+    /** \returns number of elements to skip to pass from one row (resp. column) to another
+      * for a row-major (resp. column-major) matrix.
+      * Combined with coeffRef() and the \ref flags flags, it allows a direct access to the data
+      * of the underlying matrix.
+      */
+//     inline int stride(void) const { return derived().stride(); }
+
+//     inline const NestByValue<Derived> nestByValue() const;
+
+
+    ConjugateReturnType conjugate() const;
+    const RealReturnType real() const;
+    const ImagReturnType imag() const;
+
+    template<typename CustomUnaryOp>
+    const SparseCwiseUnaryOp<CustomUnaryOp, Derived> unaryExpr(const CustomUnaryOp& func = CustomUnaryOp()) const;
+
+//     template<typename CustomBinaryOp, typename OtherDerived>
+//     const CwiseBinaryOp<CustomBinaryOp, Derived, OtherDerived>
+//     binaryExpr(const MatrixBase<OtherDerived> &other, const CustomBinaryOp& func = CustomBinaryOp()) const;
+
+
+    Scalar sum() const;
+//     Scalar trace() const;
+
+//     typename ei_traits<Derived>::Scalar minCoeff() const;
+//     typename ei_traits<Derived>::Scalar maxCoeff() const;
+
+//     typename ei_traits<Derived>::Scalar minCoeff(int* row, int* col = 0) const;
+//     typename ei_traits<Derived>::Scalar maxCoeff(int* row, int* col = 0) const;
+
+//     template<typename BinaryOp>
+//     typename ei_result_of<BinaryOp(typename ei_traits<Derived>::Scalar)>::type
+//     redux(const BinaryOp& func) const;
+
+//     template<typename Visitor>
+//     void visit(Visitor& func) const;
+
+
+    const SparseCwise<Derived> cwise() const;
+    SparseCwise<Derived> cwise();
+
+//     inline const WithFormat<Derived> format(const IOFormat& fmt) const;
+
+/////////// Array module ///////////
+    /*
+    bool all(void) const;
+    bool any(void) const;
+
+    const PartialRedux<Derived,Horizontal> rowwise() const;
+    const PartialRedux<Derived,Vertical> colwise() const;
+
+    static const CwiseNullaryOp<ei_scalar_random_op<Scalar>,Derived> Random(int rows, int cols);
+    static const CwiseNullaryOp<ei_scalar_random_op<Scalar>,Derived> Random(int size);
+    static const CwiseNullaryOp<ei_scalar_random_op<Scalar>,Derived> Random();
+
+    template<typename ThenDerived,typename ElseDerived>
+    const Select<Derived,ThenDerived,ElseDerived>
+    select(const MatrixBase<ThenDerived>& thenMatrix,
+           const MatrixBase<ElseDerived>& elseMatrix) const;
+
+    template<typename ThenDerived>
+    inline const Select<Derived,ThenDerived, NestByValue<typename ThenDerived::ConstantReturnType> >
+    select(const MatrixBase<ThenDerived>& thenMatrix, typename ThenDerived::Scalar elseScalar) const;
+
+    template<typename ElseDerived>
+    inline const Select<Derived, NestByValue<typename ElseDerived::ConstantReturnType>, ElseDerived >
+    select(typename ElseDerived::Scalar thenScalar, const MatrixBase<ElseDerived>& elseMatrix) const;
+
+    template<int p> RealScalar lpNorm() const;
+    */
+
+
+//     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;
+//     }
+
+    #ifdef EIGEN_TAUCS_SUPPORT
+    taucs_ccs_matrix asTaucsMatrix();
+    #endif
+
+    #ifdef EIGEN_CHOLMOD_SUPPORT
+    cholmod_sparse asCholmodMatrix();
+    #endif
+
+    #ifdef EIGEN_SUPERLU_SUPPORT
+    SluMatrix asSluMatrix();
+    #endif
+
+  protected:
+
+    bool m_isRValue;
+};
+
+#endif // EIGEN_SPARSEMATRIXBASE_H
diff --git a/extern/Eigen2/Eigen/src/Sparse/SparseProduct.h b/extern/Eigen2/Eigen/src/Sparse/SparseProduct.h
new file mode 100644
index 00000000000..c98a71e993b
--- /dev/null
+++ b/extern/Eigen2/Eigen/src/Sparse/SparseProduct.h
@@ -0,0 +1,415 @@
+// 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_SPARSEPRODUCT_H
+#define EIGEN_SPARSEPRODUCT_H
+
+template<typename Lhs, typename Rhs> struct ei_sparse_product_mode
+{
+  enum {
+
+    value = ((Lhs::Flags&Diagonal)==Diagonal || (Rhs::Flags&Diagonal)==Diagonal)
+          ? DiagonalProduct
+          :  (Rhs::Flags&Lhs::Flags&SparseBit)==SparseBit
+          ? SparseTimeSparseProduct
+          : (Lhs::Flags&SparseBit)==SparseBit
+          ? SparseTimeDenseProduct
+          : DenseTimeSparseProduct };
+};
+
+template<typename Lhs, typename Rhs, int ProductMode>
+struct SparseProductReturnType
+{
+  typedef const typename ei_nested<Lhs,Rhs::RowsAtCompileTime>::type LhsNested;
+  typedef const typename ei_nested<Rhs,Lhs::RowsAtCompileTime>::type RhsNested;
+
+  typedef SparseProduct<LhsNested, RhsNested, ProductMode> Type;
+};
+
+template<typename Lhs, typename Rhs>
+struct SparseProductReturnType<Lhs,Rhs,DiagonalProduct>
+{
+  typedef const typename ei_nested<Lhs,Rhs::RowsAtCompileTime>::type LhsNested;
+  typedef const typename ei_nested<Rhs,Lhs::RowsAtCompileTime>::type RhsNested;
+
+  typedef SparseDiagonalProduct<LhsNested, RhsNested> Type;
+};
+
+// sparse product return type specialization
+template<typename Lhs, typename Rhs>
+struct SparseProductReturnType<Lhs,Rhs,SparseTimeSparseProduct>
+{
+  typedef typename ei_traits<Lhs>::Scalar Scalar;
+  enum {
+    LhsRowMajor = ei_traits<Lhs>::Flags & RowMajorBit,
+    RhsRowMajor = ei_traits<Rhs>::Flags & RowMajorBit,
+    TransposeRhs = (!LhsRowMajor) && RhsRowMajor,
+    TransposeLhs = LhsRowMajor && (!RhsRowMajor)
+  };
+
+  // FIXME if we transpose let's evaluate to a LinkedVectorMatrix since it is the
+  // type of the temporary to perform the transpose op
+  typedef typename ei_meta_if<TransposeLhs,
+    SparseMatrix<Scalar,0>,
+    const typename ei_nested<Lhs,Rhs::RowsAtCompileTime>::type>::ret LhsNested;
+
+  typedef typename ei_meta_if<TransposeRhs,
+    SparseMatrix<Scalar,0>,
+    const typename ei_nested<Rhs,Lhs::RowsAtCompileTime>::type>::ret RhsNested;
+
+  typedef SparseProduct<LhsNested, RhsNested, SparseTimeSparseProduct> Type;
+};
+
+template<typename LhsNested, typename RhsNested, int ProductMode>
+struct ei_traits<SparseProduct<LhsNested, RhsNested, ProductMode> >
+{
+  // clean the nested types:
+  typedef typename ei_cleantype<LhsNested>::type _LhsNested;
+  typedef typename ei_cleantype<RhsNested>::type _RhsNested;
+  typedef typename _LhsNested::Scalar Scalar;
+
+  enum {
+    LhsCoeffReadCost = _LhsNested::CoeffReadCost,
+    RhsCoeffReadCost = _RhsNested::CoeffReadCost,
+    LhsFlags = _LhsNested::Flags,
+    RhsFlags = _RhsNested::Flags,
+
+    RowsAtCompileTime = _LhsNested::RowsAtCompileTime,
+    ColsAtCompileTime = _RhsNested::ColsAtCompileTime,
+    InnerSize = EIGEN_ENUM_MIN(_LhsNested::ColsAtCompileTime, _RhsNested::RowsAtCompileTime),
+
+    MaxRowsAtCompileTime = _LhsNested::MaxRowsAtCompileTime,
+    MaxColsAtCompileTime = _RhsNested::MaxColsAtCompileTime,
+
+//     LhsIsRowMajor = (LhsFlags & RowMajorBit)==RowMajorBit,
+//     RhsIsRowMajor = (RhsFlags & RowMajorBit)==RowMajorBit,
+
+    EvalToRowMajor = (RhsFlags & LhsFlags & RowMajorBit),
+    ResultIsSparse = ProductMode==SparseTimeSparseProduct || ProductMode==DiagonalProduct,
+
+    RemovedBits = ~( (EvalToRowMajor ? 0 : RowMajorBit) | (ResultIsSparse ? 0 : SparseBit) ),
+
+    Flags = (int(LhsFlags | RhsFlags) & HereditaryBits & RemovedBits)
+          | EvalBeforeAssigningBit
+          | EvalBeforeNestingBit,
+
+    CoeffReadCost = Dynamic
+  };
+
+  typedef typename ei_meta_if<ResultIsSparse,
+    SparseMatrixBase<SparseProduct<LhsNested, RhsNested, ProductMode> >,
+    MatrixBase<SparseProduct<LhsNested, RhsNested, ProductMode> > >::ret Base;
+};
+
+template<typename LhsNested, typename RhsNested, int ProductMode>
+class SparseProduct : ei_no_assignment_operator,
+  public ei_traits<SparseProduct<LhsNested, RhsNested, ProductMode> >::Base
+{
+  public:
+
+    EIGEN_GENERIC_PUBLIC_INTERFACE(SparseProduct)
+
+  private:
+
+    typedef typename ei_traits<SparseProduct>::_LhsNested _LhsNested;
+    typedef typename ei_traits<SparseProduct>::_RhsNested _RhsNested;
+
+  public:
+
+    template<typename Lhs, typename Rhs>
+    EIGEN_STRONG_INLINE SparseProduct(const Lhs& lhs, const Rhs& rhs)
+      : m_lhs(lhs), m_rhs(rhs)
+    {
+      ei_assert(lhs.cols() == rhs.rows());
+
+      enum {
+        ProductIsValid = _LhsNested::ColsAtCompileTime==Dynamic
+                      || _RhsNested::RowsAtCompileTime==Dynamic
+                      || int(_LhsNested::ColsAtCompileTime)==int(_RhsNested::RowsAtCompileTime),
+        AreVectors = _LhsNested::IsVectorAtCompileTime && _RhsNested::IsVectorAtCompileTime,
+        SameSizes = EIGEN_PREDICATE_SAME_MATRIX_SIZE(_LhsNested,_RhsNested)
+      };
+      // note to the lost user:
+      //    * for a dot product use: v1.dot(v2)
+      //    * for a coeff-wise product use: v1.cwise()*v2
+      EIGEN_STATIC_ASSERT(ProductIsValid || !(AreVectors && SameSizes),
+        INVALID_VECTOR_VECTOR_PRODUCT__IF_YOU_WANTED_A_DOT_OR_COEFF_WISE_PRODUCT_YOU_MUST_USE_THE_EXPLICIT_FUNCTIONS)
+      EIGEN_STATIC_ASSERT(ProductIsValid || !(SameSizes && !AreVectors),
+        INVALID_MATRIX_PRODUCT__IF_YOU_WANTED_A_COEFF_WISE_PRODUCT_YOU_MUST_USE_THE_EXPLICIT_FUNCTION)
+      EIGEN_STATIC_ASSERT(ProductIsValid || SameSizes, INVALID_MATRIX_PRODUCT)
+    }
+
+    EIGEN_STRONG_INLINE int rows() const { return m_lhs.rows(); }
+    EIGEN_STRONG_INLINE int cols() const { return m_rhs.cols(); }
+
+    EIGEN_STRONG_INLINE const _LhsNested& lhs() const { return m_lhs; }
+    EIGEN_STRONG_INLINE const _RhsNested& rhs() const { return m_rhs; }
+
+  protected:
+    LhsNested m_lhs;
+    RhsNested m_rhs;
+};
+
+// perform a pseudo in-place sparse * sparse product assuming all matrices are col major
+template<typename Lhs, typename Rhs, typename ResultType>
+static void ei_sparse_product_impl(const Lhs& lhs, const Rhs& rhs, ResultType& res)
+{
+  typedef typename ei_traits<typename ei_cleantype<Lhs>::type>::Scalar Scalar;
+
+  // make sure to call innerSize/outerSize since we fake the storage order.
+  int rows = lhs.innerSize();
+  int cols = rhs.outerSize();
+  //int size = lhs.outerSize();
+  ei_assert(lhs.outerSize() == rhs.innerSize());
+
+  // allocate a temporary buffer
+  AmbiVector<Scalar> tempVector(rows);
+
+  // estimate the number of non zero entries
+  float ratioLhs = float(lhs.nonZeros())/(float(lhs.rows())*float(lhs.cols()));
+  float avgNnzPerRhsColumn = float(rhs.nonZeros())/float(cols);
+  float ratioRes = std::min(ratioLhs * avgNnzPerRhsColumn, 1.f);
+
+  res.resize(rows, cols);
+  res.startFill(int(ratioRes*rows*cols));
+  for (int j=0; j<cols; ++j)
+  {
+    // let's do a more accurate determination of the nnz ratio for the current column j of res
+    //float ratioColRes = std::min(ratioLhs * rhs.innerNonZeros(j), 1.f);
+    // FIXME find a nice way to get the number of nonzeros of a sub matrix (here an inner vector)
+    float ratioColRes = ratioRes;
+    tempVector.init(ratioColRes);
+    tempVector.setZero();
+    for (typename Rhs::InnerIterator rhsIt(rhs, j); rhsIt; ++rhsIt)
+    {
+      // FIXME should be written like this: tmp += rhsIt.value() * lhs.col(rhsIt.index())
+      tempVector.restart();
+      Scalar x = rhsIt.value();
+      for (typename Lhs::InnerIterator lhsIt(lhs, rhsIt.index()); lhsIt; ++lhsIt)
+      {
+        tempVector.coeffRef(lhsIt.index()) += lhsIt.value() * x;
+      }
+    }
+    for (typename AmbiVector<Scalar>::Iterator it(tempVector); it; ++it)
+      if (ResultType::Flags&RowMajorBit)
+        res.fill(j,it.index()) = it.value();
+      else
+        res.fill(it.index(), j) = it.value();
+  }
+  res.endFill();
+}
+
+template<typename Lhs, typename Rhs, typename ResultType,
+  int LhsStorageOrder = ei_traits<Lhs>::Flags&RowMajorBit,
+  int RhsStorageOrder = ei_traits<Rhs>::Flags&RowMajorBit,
+  int ResStorageOrder = ei_traits<ResultType>::Flags&RowMajorBit>
+struct ei_sparse_product_selector;
+
+template<typename Lhs, typename Rhs, typename ResultType>
+struct ei_sparse_product_selector<Lhs,Rhs,ResultType,ColMajor,ColMajor,ColMajor>
+{
+  typedef typename ei_traits<typename ei_cleantype<Lhs>::type>::Scalar Scalar;
+
+  static void run(const Lhs& lhs, const Rhs& rhs, ResultType& res)
+  {
+    typename ei_cleantype<ResultType>::type _res(res.rows(), res.cols());
+    ei_sparse_product_impl<Lhs,Rhs,ResultType>(lhs, rhs, _res);
+    res.swap(_res);
+  }
+};
+
+template<typename Lhs, typename Rhs, typename ResultType>
+struct ei_sparse_product_selector<Lhs,Rhs,ResultType,ColMajor,ColMajor,RowMajor>
+{
+  static void run(const Lhs& lhs, const Rhs& rhs, ResultType& res)
+  {
+    // we need a col-major matrix to hold the result
+    typedef SparseMatrix<typename ResultType::Scalar> SparseTemporaryType;
+    SparseTemporaryType _res(res.rows(), res.cols());
+    ei_sparse_product_impl<Lhs,Rhs,SparseTemporaryType>(lhs, rhs, _res);
+    res = _res;
+  }
+};
+
+template<typename Lhs, typename Rhs, typename ResultType>
+struct ei_sparse_product_selector<Lhs,Rhs,ResultType,RowMajor,RowMajor,RowMajor>
+{
+  static void run(const Lhs& lhs, const Rhs& rhs, ResultType& res)
+  {
+    // let's transpose the product to get a column x column product
+    typename ei_cleantype<ResultType>::type _res(res.rows(), res.cols());
+    ei_sparse_product_impl<Rhs,Lhs,ResultType>(rhs, lhs, _res);
+    res.swap(_res);
+  }
+};
+
+template<typename Lhs, typename Rhs, typename ResultType>
+struct ei_sparse_product_selector<Lhs,Rhs,ResultType,RowMajor,RowMajor,ColMajor>
+{
+  static void run(const Lhs& lhs, const Rhs& rhs, ResultType& res)
+  {
+    // let's transpose the product to get a column x column product
+    typedef SparseMatrix<typename ResultType::Scalar> SparseTemporaryType;
+    SparseTemporaryType _res(res.cols(), res.rows());
+    ei_sparse_product_impl<Rhs,Lhs,SparseTemporaryType>(rhs, lhs, _res);
+    res = _res.transpose();
+  }
+};
+
+// NOTE eventually let's transpose one argument even in this case since it might be expensive if
+// the result is not dense.
+// template<typename Lhs, typename Rhs, typename ResultType, int ResStorageOrder>
+// struct ei_sparse_product_selector<Lhs,Rhs,ResultType,RowMajor,ColMajor,ResStorageOrder>
+// {
+//   static void run(const Lhs& lhs, const Rhs& rhs, ResultType& res)
+//   {
+//     // trivial product as lhs.row/rhs.col dot products
+//     // loop over the preferred order of the result
+//   }
+// };
+
+// NOTE the 2 others cases (col row *) must never occurs since they are caught
+// by ProductReturnType which transform it to (col col *) by evaluating rhs.
+
+
+// template<typename Derived>
+// template<typename Lhs, typename Rhs>
+// inline Derived& SparseMatrixBase<Derived>::lazyAssign(const SparseProduct<Lhs,Rhs>& product)
+// {
+// //   std::cout << "sparse product to dense\n";
+//   ei_sparse_product_selector<
+//     typename ei_cleantype<Lhs>::type,
+//     typename ei_cleantype<Rhs>::type,
+//     typename ei_cleantype<Derived>::type>::run(product.lhs(),product.rhs(),derived());
+//   return derived();
+// }
+
+// sparse = sparse * sparse
+template<typename Derived>
+template<typename Lhs, typename Rhs>
+inline Derived& SparseMatrixBase<Derived>::operator=(const SparseProduct<Lhs,Rhs,SparseTimeSparseProduct>& product)
+{
+  ei_sparse_product_selector<
+    typename ei_cleantype<Lhs>::type,
+    typename ei_cleantype<Rhs>::type,
+    Derived>::run(product.lhs(),product.rhs(),derived());
+  return derived();
+}
+
+// dense = sparse * dense
+// template<typename Derived>
+// template<typename Lhs, typename Rhs>
+// Derived& MatrixBase<Derived>::lazyAssign(const SparseProduct<Lhs,Rhs,SparseTimeDenseProduct>& product)
+// {
+//   typedef typename ei_cleantype<Lhs>::type _Lhs;
+//   typedef typename _Lhs::InnerIterator LhsInnerIterator;
+//   enum { LhsIsRowMajor = (_Lhs::Flags&RowMajorBit)==RowMajorBit };
+//   derived().setZero();
+//   for (int j=0; j<product.lhs().outerSize(); ++j)
+//     for (LhsInnerIterator i(product.lhs(),j); i; ++i)
+//       derived().row(LhsIsRowMajor ? j : i.index()) += i.value() * product.rhs().row(LhsIsRowMajor ? i.index() : j);
+//   return derived();
+// }
+
+template<typename Derived>
+template<typename Lhs, typename Rhs>
+Derived& MatrixBase<Derived>::lazyAssign(const SparseProduct<Lhs,Rhs,SparseTimeDenseProduct>& product)
+{
+  typedef typename ei_cleantype<Lhs>::type _Lhs;
+  typedef typename ei_cleantype<Rhs>::type _Rhs;
+  typedef typename _Lhs::InnerIterator LhsInnerIterator;
+  enum {
+    LhsIsRowMajor = (_Lhs::Flags&RowMajorBit)==RowMajorBit,
+    LhsIsSelfAdjoint = (_Lhs::Flags&SelfAdjointBit)==SelfAdjointBit,
+    ProcessFirstHalf = LhsIsSelfAdjoint
+      && (   ((_Lhs::Flags&(UpperTriangularBit|LowerTriangularBit))==0)
+          || ( (_Lhs::Flags&UpperTriangularBit) && !LhsIsRowMajor)
+          || ( (_Lhs::Flags&LowerTriangularBit) && LhsIsRowMajor) ),
+    ProcessSecondHalf = LhsIsSelfAdjoint && (!ProcessFirstHalf)
+  };
+  derived().setZero();
+  for (int j=0; j<product.lhs().outerSize(); ++j)
+  {
+    LhsInnerIterator i(product.lhs(),j);
+    if (ProcessSecondHalf && i && (i.index()==j))
+    {
+      derived().row(j) += i.value() * product.rhs().row(j);
+      ++i;
+    }
+    Block<Derived,1,Derived::ColsAtCompileTime> res(derived().row(LhsIsRowMajor ? j : 0));
+    for (; (ProcessFirstHalf ? i && i.index() < j : i) ; ++i)
+    {
+      if (LhsIsSelfAdjoint)
+      {
+        int a = LhsIsRowMajor ? j : i.index();
+        int b = LhsIsRowMajor ? i.index() : j;
+        Scalar v = i.value();
+        derived().row(a) += (v) * product.rhs().row(b);
+        derived().row(b) += ei_conj(v) * product.rhs().row(a);
+      }
+      else if (LhsIsRowMajor)
+        res += i.value() * product.rhs().row(i.index());
+      else
+        derived().row(i.index()) += i.value() * product.rhs().row(j);
+    }
+    if (ProcessFirstHalf && i && (i.index()==j))
+      derived().row(j) += i.value() * product.rhs().row(j);
+  }
+  return derived();
+}
+
+// dense = dense * sparse
+template<typename Derived>
+template<typename Lhs, typename Rhs>
+Derived& MatrixBase<Derived>::lazyAssign(const SparseProduct<Lhs,Rhs,DenseTimeSparseProduct>& product)
+{
+  typedef typename ei_cleantype<Rhs>::type _Rhs;
+  typedef typename _Rhs::InnerIterator RhsInnerIterator;
+  enum { RhsIsRowMajor = (_Rhs::Flags&RowMajorBit)==RowMajorBit };
+  derived().setZero();
+  for (int j=0; j<product.rhs().outerSize(); ++j)
+    for (RhsInnerIterator i(product.rhs(),j); i; ++i)
+      derived().col(RhsIsRowMajor ? i.index() : j) += i.value() * product.lhs().col(RhsIsRowMajor ? j : i.index());
+  return derived();
+}
+
+// sparse * sparse
+template<typename Derived>
+template<typename OtherDerived>
+EIGEN_STRONG_INLINE const typename SparseProductReturnType<Derived,OtherDerived>::Type
+SparseMatrixBase<Derived>::operator*(const SparseMatrixBase<OtherDerived> &other) const
+{
+  return typename SparseProductReturnType<Derived,OtherDerived>::Type(derived(), other.derived());
+}
+
+// sparse * dense
+template<typename Derived>
+template<typename OtherDerived>
+EIGEN_STRONG_INLINE const typename SparseProductReturnType<Derived,OtherDerived>::Type
+SparseMatrixBase<Derived>::operator*(const MatrixBase<OtherDerived> &other) const
+{
+  return typename SparseProductReturnType<Derived,OtherDerived>::Type(derived(), other.derived());
+}
+
+#endif // EIGEN_SPARSEPRODUCT_H
diff --git a/extern/Eigen2/Eigen/src/Sparse/SparseRedux.h b/extern/Eigen2/Eigen/src/Sparse/SparseRedux.h
new file mode 100644
index 00000000000..f0d3705488e
--- /dev/null
+++ b/extern/Eigen2/Eigen/src/Sparse/SparseRedux.h
@@ -0,0 +1,40 @@
+// 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>
+typename ei_traits<Derived>::Scalar
+SparseMatrixBase<Derived>::sum() const
+{
+  ei_assert(rows()>0 && cols()>0 && "you are using a non initialized matrix");
+  Scalar res = 0;
+  for (int j=0; j<outerSize(); ++j)
+    for (typename Derived::InnerIterator iter(derived(),j); iter; ++iter)
+      res += iter.value();
+  return res;
+}
+
+#endif // EIGEN_SPARSEREDUX_H
diff --git a/extern/Eigen2/Eigen/src/Sparse/SparseTranspose.h b/extern/Eigen2/Eigen/src/Sparse/SparseTranspose.h
new file mode 100644
index 00000000000..89a14d70707
--- /dev/null
+++ b/extern/Eigen2/Eigen/src/Sparse/SparseTranspose.h
@@ -0,0 +1,85 @@
+// 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_SPARSETRANSPOSE_H
+#define EIGEN_SPARSETRANSPOSE_H
+
+template<typename MatrixType>
+struct ei_traits<SparseTranspose<MatrixType> > : ei_traits<Transpose<MatrixType> >
+{};
+
+template<typename MatrixType> class SparseTranspose
+  : public SparseMatrixBase<SparseTranspose<MatrixType> >
+{
+  public:
+
+    EIGEN_GENERIC_PUBLIC_INTERFACE(SparseTranspose)
+
+    class InnerIterator;
+    class ReverseInnerIterator;
+
+    inline SparseTranspose(const MatrixType& matrix) : m_matrix(matrix) {}
+
+    //EIGEN_INHERIT_ASSIGNMENT_OPERATORS(SparseTranspose)
+
+    inline int rows() const { return m_matrix.cols(); }
+    inline int cols() const { return m_matrix.rows(); }
+    inline int nonZeros() const { return m_matrix.nonZeros(); }
+
+    // FIXME should be keep them ?
+    inline Scalar& coeffRef(int row, int col)
+    { return m_matrix.const_cast_derived().coeffRef(col, row); }
+
+    inline const Scalar coeff(int row, int col) const
+    { return m_matrix.coeff(col, row); }
+
+    inline const Scalar coeff(int index) const
+    { return m_matrix.coeff(index); }
+
+    inline Scalar& coeffRef(int index)
+    { return m_matrix.const_cast_derived().coeffRef(index); }
+
+  protected:
+    const typename MatrixType::Nested m_matrix;
+};
+
+template<typename MatrixType> class SparseTranspose<MatrixType>::InnerIterator : public MatrixType::InnerIterator
+{
+  public:
+
+    EIGEN_STRONG_INLINE InnerIterator(const SparseTranspose& trans, int outer)
+      : MatrixType::InnerIterator(trans.m_matrix, outer)
+    {}
+};
+
+template<typename MatrixType> class SparseTranspose<MatrixType>::ReverseInnerIterator : public MatrixType::ReverseInnerIterator
+{
+  public:
+
+    EIGEN_STRONG_INLINE ReverseInnerIterator(const SparseTranspose& xpr, int outer)
+      : MatrixType::ReverseInnerIterator(xpr.m_matrix, outer)
+    {}
+};
+
+#endif // EIGEN_SPARSETRANSPOSE_H
diff --git a/extern/Eigen2/Eigen/src/Sparse/SparseUtil.h b/extern/Eigen2/Eigen/src/Sparse/SparseUtil.h
new file mode 100644
index 00000000000..393cdda6ea2
--- /dev/null
+++ b/extern/Eigen2/Eigen/src/Sparse/SparseUtil.h
@@ -0,0 +1,148 @@
+// 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_SPARSEUTIL_H
+#define EIGEN_SPARSEUTIL_H
+
+#ifdef NDEBUG
+#define EIGEN_DBG_SPARSE(X)
+#else
+#define EIGEN_DBG_SPARSE(X) X
+#endif
+
+#define EIGEN_SPARSE_INHERIT_ASSIGNMENT_OPERATOR(Derived, Op) \
+template<typename OtherDerived> \
+EIGEN_STRONG_INLINE Derived& operator Op(const Eigen::SparseMatrixBase<OtherDerived>& other) \
+{ \
+  return Base::operator Op(other.derived()); \
+} \
+EIGEN_STRONG_INLINE Derived& operator Op(const Derived& other) \
+{ \
+  return Base::operator Op(other); \
+}
+
+#define EIGEN_SPARSE_INHERIT_SCALAR_ASSIGNMENT_OPERATOR(Derived, Op) \
+template<typename Other> \
+EIGEN_STRONG_INLINE Derived& operator Op(const Other& scalar) \
+{ \
+  return Base::operator Op(scalar); \
+}
+
+#define EIGEN_SPARSE_INHERIT_ASSIGNMENT_OPERATORS(Derived) \
+EIGEN_SPARSE_INHERIT_ASSIGNMENT_OPERATOR(Derived, =) \
+EIGEN_SPARSE_INHERIT_ASSIGNMENT_OPERATOR(Derived, +=) \
+EIGEN_SPARSE_INHERIT_ASSIGNMENT_OPERATOR(Derived, -=) \
+EIGEN_SPARSE_INHERIT_SCALAR_ASSIGNMENT_OPERATOR(Derived, *=) \
+EIGEN_SPARSE_INHERIT_SCALAR_ASSIGNMENT_OPERATOR(Derived, /=)
+
+#define _EIGEN_SPARSE_GENERIC_PUBLIC_INTERFACE(Derived, BaseClass) \
+typedef BaseClass Base; \
+typedef typename Eigen::ei_traits<Derived>::Scalar Scalar; \
+typedef typename Eigen::NumTraits<Scalar>::Real RealScalar; \
+typedef typename Eigen::ei_nested<Derived>::type Nested; \
+enum { RowsAtCompileTime = Eigen::ei_traits<Derived>::RowsAtCompileTime, \
+       ColsAtCompileTime = Eigen::ei_traits<Derived>::ColsAtCompileTime, \
+       Flags = Eigen::ei_traits<Derived>::Flags, \
+       CoeffReadCost = Eigen::ei_traits<Derived>::CoeffReadCost, \
+       SizeAtCompileTime = Base::SizeAtCompileTime, \
+       IsVectorAtCompileTime = Base::IsVectorAtCompileTime };
+
+#define EIGEN_SPARSE_GENERIC_PUBLIC_INTERFACE(Derived) \
+_EIGEN_SPARSE_GENERIC_PUBLIC_INTERFACE(Derived, Eigen::SparseMatrixBase<Derived>)
+
+enum SparseBackend {
+  DefaultBackend,
+  Taucs,
+  Cholmod,
+  SuperLU,
+  UmfPack
+};
+
+// solver flags
+enum {
+  CompleteFactorization       = 0x0000,  // the default
+  IncompleteFactorization     = 0x0001,
+  MemoryEfficient             = 0x0002,
+
+  // For LLT Cholesky:
+  SupernodalMultifrontal      = 0x0010,
+  SupernodalLeftLooking       = 0x0020,
+
+  // Ordering methods:
+  NaturalOrdering             = 0x0100, // the default
+  MinimumDegree_AT_PLUS_A     = 0x0200,
+  MinimumDegree_ATA           = 0x0300,
+  ColApproxMinimumDegree      = 0x0400,
+  Metis                       = 0x0500,
+  Scotch                      = 0x0600,
+  Chaco                       = 0x0700,
+  OrderingMask                = 0x0f00
+};
+
+template<typename Derived> class SparseMatrixBase;
+template<typename _Scalar, int _Flags = 0> class SparseMatrix;
+template<typename _Scalar, int _Flags = 0> class DynamicSparseMatrix;
+template<typename _Scalar, int _Flags = 0> class SparseVector;
+template<typename _Scalar, int _Flags = 0> class MappedSparseMatrix;
+
+template<typename MatrixType>                            class SparseTranspose;
+template<typename MatrixType, int Size>                  class SparseInnerVectorSet;
+template<typename Derived>                               class SparseCwise;
+template<typename UnaryOp,   typename MatrixType>        class SparseCwiseUnaryOp;
+template<typename BinaryOp,  typename Lhs, typename Rhs> class SparseCwiseBinaryOp;
+template<typename ExpressionType,
+         unsigned int Added, unsigned int Removed>       class SparseFlagged;
+template<typename Lhs, typename Rhs>                     class SparseDiagonalProduct;
+
+template<typename Lhs, typename Rhs> struct ei_sparse_product_mode;
+template<typename Lhs, typename Rhs, int ProductMode = ei_sparse_product_mode<Lhs,Rhs>::value> struct SparseProductReturnType;
+
+const int CoherentAccessPattern  = 0x1;
+const int InnerRandomAccessPattern  = 0x2 | CoherentAccessPattern;
+const int OuterRandomAccessPattern  = 0x4 | CoherentAccessPattern;
+const int RandomAccessPattern       = 0x8 | OuterRandomAccessPattern | InnerRandomAccessPattern;
+
+// const int AccessPatternNotSupported = 0x0;
+// const int AccessPatternSupported    = 0x1;
+// 
+// template<typename MatrixType, int AccessPattern> struct ei_support_access_pattern
+// {
+//   enum { ret = (int(ei_traits<MatrixType>::SupportedAccessPatterns) & AccessPattern) == AccessPattern
+//              ? AccessPatternSupported
+//              : AccessPatternNotSupported
+//   };
+// };
+
+template<typename T> class ei_eval<T,IsSparse>
+{
+    typedef typename ei_traits<T>::Scalar _Scalar;
+    enum {
+          _Flags = ei_traits<T>::Flags
+    };
+
+  public:
+    typedef SparseMatrix<_Scalar, _Flags> type;
+};
+
+#endif // EIGEN_SPARSEUTIL_H
diff --git a/extern/Eigen2/Eigen/src/Sparse/SparseVector.h b/extern/Eigen2/Eigen/src/Sparse/SparseVector.h
new file mode 100644
index 00000000000..8e5a6efeda8
--- /dev/null
+++ b/extern/Eigen2/Eigen/src/Sparse/SparseVector.h
@@ -0,0 +1,365 @@
+// This file is part of Eigen, a lightweight C++ template library
+// for linear algebra. Eigen itself is part of the KDE project.
+//
+// Copyright (C) 2008-2009 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_SPARSEVECTOR_H
+#define EIGEN_SPARSEVECTOR_H
+
+/** \class SparseVector
+  *
+  * \brief a sparse vector class
+  *
+  * \param _Scalar the scalar type, i.e. the type of the coefficients
+  *
+  * See http://www.netlib.org/linalg/html_templates/node91.html for details on the storage scheme.
+  *
+  */
+template<typename _Scalar, int _Flags>
+struct ei_traits<SparseVector<_Scalar, _Flags> >
+{
+  typedef _Scalar Scalar;
+  enum {
+    IsColVector = _Flags & RowMajorBit ? 0 : 1,
+
+    RowsAtCompileTime = IsColVector ? Dynamic : 1,
+    ColsAtCompileTime = IsColVector ? 1 : Dynamic,
+    MaxRowsAtCompileTime = RowsAtCompileTime,
+    MaxColsAtCompileTime = ColsAtCompileTime,
+    Flags = SparseBit | _Flags,
+    CoeffReadCost = NumTraits<Scalar>::ReadCost,
+    SupportedAccessPatterns = InnerRandomAccessPattern
+  };
+};
+
+template<typename _Scalar, int _Flags>
+class SparseVector
+  : public SparseMatrixBase<SparseVector<_Scalar, _Flags> >
+{
+  public:
+    EIGEN_SPARSE_GENERIC_PUBLIC_INTERFACE(SparseVector)
+    EIGEN_SPARSE_INHERIT_ASSIGNMENT_OPERATOR(SparseVector, +=)
+    EIGEN_SPARSE_INHERIT_ASSIGNMENT_OPERATOR(SparseVector, -=)
+//     EIGEN_SPARSE_INHERIT_ASSIGNMENT_OPERATOR(SparseVector, =)
+
+  protected:
+  public:
+
+    typedef SparseMatrixBase<SparseVector> SparseBase;
+    enum { IsColVector = ei_traits<SparseVector>::IsColVector };
+
+    CompressedStorage<Scalar> m_data;
+    int m_size;
+    
+    CompressedStorage<Scalar>& _data() { return m_data; }
+    CompressedStorage<Scalar>& _data() const { return m_data; }
+
+  public:
+
+    EIGEN_STRONG_INLINE int rows() const { return IsColVector ? m_size : 1; }
+    EIGEN_STRONG_INLINE int cols() const { return IsColVector ? 1 : m_size; }
+    EIGEN_STRONG_INLINE int innerSize() const { return m_size; }
+    EIGEN_STRONG_INLINE int outerSize() const { return 1; }
+    EIGEN_STRONG_INLINE int innerNonZeros(int j) const { ei_assert(j==0); return m_size; }
+
+    EIGEN_STRONG_INLINE const Scalar* _valuePtr() const { return &m_data.value(0); }
+    EIGEN_STRONG_INLINE Scalar* _valuePtr() { return &m_data.value(0); }
+
+    EIGEN_STRONG_INLINE const int* _innerIndexPtr() const { return &m_data.index(0); }
+    EIGEN_STRONG_INLINE int* _innerIndexPtr() { return &m_data.index(0); }
+
+    inline Scalar coeff(int row, int col) const
+    {
+      ei_assert((IsColVector ? col : row)==0);
+      return coeff(IsColVector ? row : col);
+    }
+    inline Scalar coeff(int i) const { return m_data.at(i); }
+
+    inline Scalar& coeffRef(int row, int col)
+    {
+      ei_assert((IsColVector ? col : row)==0);
+      return coeff(IsColVector ? row : col);
+    }
+
+    /** \returns a reference to the coefficient value at given index \a i
+      * This operation involes a log(rho*size) binary search. If the coefficient does not
+      * exist yet, then a sorted insertion into a sequential buffer is performed.
+      * 
+      * This insertion might be very costly if the number of nonzeros above \a i is large.
+      */
+    inline Scalar& coeffRef(int i)
+    {
+      return m_data.atWithInsertion(i);
+    }
+
+  public:
+
+    class InnerIterator;
+
+    inline void setZero() { m_data.clear(); }
+
+    /** \returns the number of non zero coefficients */
+    inline int nonZeros() const  { return m_data.size(); }
+
+    /**
+      */
+    inline void reserve(int reserveSize) { m_data.reserve(reserveSize); }
+    
+    inline void startFill(int reserve)
+    {
+      setZero();
+      m_data.reserve(reserve);
+    }
+
+    /**
+      */
+    inline Scalar& fill(int r, int c)
+    {
+      ei_assert(r==0 || c==0);
+      return fill(IsColVector ? r : c);
+    }
+    
+    inline Scalar& fill(int i)
+    {
+      m_data.append(0, i);
+      return m_data.value(m_data.size()-1);
+    }
+    
+    inline Scalar& fillrand(int r, int c)
+    {
+      ei_assert(r==0 || c==0);
+      return fillrand(IsColVector ? r : c);
+    }
+
+    /** Like fill() but with random coordinates.
+      */
+    inline Scalar& fillrand(int i)
+    {
+      int startId = 0;
+      int id = m_data.size() - 1;
+      m_data.resize(id+2,1);
+
+      while ( (id >= startId) && (m_data.index(id) > i) )
+      {
+        m_data.index(id+1) = m_data.index(id);
+        m_data.value(id+1) = m_data.value(id);
+        --id;
+      }
+      m_data.index(id+1) = i;
+      m_data.value(id+1) = 0;
+      return m_data.value(id+1);
+    }
+    
+    inline void endFill() {}
+    
+    void prune(Scalar reference, RealScalar epsilon = precision<RealScalar>())
+    {
+      m_data.prune(reference,epsilon);
+    }
+    
+    void resize(int rows, int cols)
+    {
+      ei_assert(rows==1 || cols==1);
+      resize(IsColVector ? rows : cols);
+    }
+
+    void resize(int newSize)
+    {
+      m_size = newSize;
+      m_data.clear();
+    }
+
+    void resizeNonZeros(int size) { m_data.resize(size); }
+
+    inline SparseVector() : m_size(0) { resize(0); }
+
+    inline SparseVector(int size) : m_size(0) { resize(size); }
+    
+    inline SparseVector(int rows, int cols) : m_size(0) { resize(rows,cols); }
+
+    template<typename OtherDerived>
+    inline SparseVector(const MatrixBase<OtherDerived>& other)
+      : m_size(0)
+    {
+      *this = other.derived();
+    }
+    
+    template<typename OtherDerived>
+    inline SparseVector(const SparseMatrixBase<OtherDerived>& other)
+      : m_size(0)
+    {
+      *this = other.derived();
+    }
+
+    inline SparseVector(const SparseVector& other)
+      : m_size(0)
+    {
+      *this = other.derived();
+    }
+
+    inline void swap(SparseVector& other)
+    {
+      std::swap(m_size, other.m_size);
+      m_data.swap(other.m_data);
+    }
+
+    inline SparseVector& operator=(const SparseVector& other)
+    {
+      if (other.isRValue())
+      {
+        swap(other.const_cast_derived());
+      }
+      else
+      {
+        resize(other.size());
+        m_data = other.m_data;
+      }
+      return *this;
+    }
+
+    template<typename OtherDerived>
+    inline SparseVector& operator=(const SparseMatrixBase<OtherDerived>& other)
+    {
+      return Base::operator=(other);
+    }
+    
+//       const bool needToTranspose = (Flags & RowMajorBit) != (OtherDerived::Flags & RowMajorBit);
+//       if (needToTranspose)
+//       {
+//         // two passes algorithm:
+//         //  1 - compute the number of coeffs per dest inner vector
+//         //  2 - do the actual copy/eval
+//         // Since each coeff of the rhs has to be evaluated twice, let's evauluate it if needed
+//         typedef typename ei_nested<OtherDerived,2>::type OtherCopy;
+//         OtherCopy otherCopy(other.derived());
+//         typedef typename ei_cleantype<OtherCopy>::type _OtherCopy;
+//
+//         resize(other.rows(), other.cols());
+//         Eigen::Map<VectorXi>(m_outerIndex,outerSize()).setZero();
+//         // pass 1
+//         // FIXME the above copy could be merged with that pass
+//         for (int j=0; j<otherCopy.outerSize(); ++j)
+//           for (typename _OtherCopy::InnerIterator it(otherCopy, j); it; ++it)
+//             ++m_outerIndex[it.index()];
+//
+//         // prefix sum
+//         int count = 0;
+//         VectorXi positions(outerSize());
+//         for (int j=0; j<outerSize(); ++j)
+//         {
+//           int tmp = m_outerIndex[j];
+//           m_outerIndex[j] = count;
+//           positions[j] = count;
+//           count += tmp;
+//         }
+//         m_outerIndex[outerSize()] = count;
+//         // alloc
+//         m_data.resize(count);
+//         // pass 2
+//         for (int j=0; j<otherCopy.outerSize(); ++j)
+//           for (typename _OtherCopy::InnerIterator it(otherCopy, j); it; ++it)
+//           {
+//             int pos = positions[it.index()]++;
+//             m_data.index(pos) = j;
+//             m_data.value(pos) = it.value();
+//           }
+//
+//         return *this;
+//       }
+//       else
+//       {
+//         // there is no special optimization
+//         return SparseMatrixBase<SparseMatrix>::operator=(other.derived());
+//       }
+//     }
+
+    friend std::ostream & operator << (std::ostream & s, const SparseVector& m)
+    {
+      for (unsigned int i=0; i<m.nonZeros(); ++i)
+        s << "(" << m.m_data.value(i) << "," << m.m_data.index(i) << ") ";
+      s << std::endl;
+      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() {}
+};
+
+template<typename Scalar, int _Flags>
+class SparseVector<Scalar,_Flags>::InnerIterator
+{
+  public:
+    InnerIterator(const SparseVector& vec, int outer=0)
+      : m_data(vec.m_data), m_id(0), m_end(m_data.size())
+    {
+      ei_assert(outer==0);
+    }
+    
+    InnerIterator(const CompressedStorage<Scalar>& data)
+      : m_data(data), m_id(0), m_end(m_data.size())
+    {}
+
+    template<unsigned int Added, unsigned int Removed>
+    InnerIterator(const Flagged<SparseVector,Added,Removed>& vec, int outer)
+      : m_data(vec._expression().m_data), m_id(0), m_end(m_data.size())
+    {}
+
+    inline InnerIterator& operator++() { m_id++; return *this; }
+
+    inline Scalar value() const { return m_data.value(m_id); }
+    inline Scalar& valueRef() { return const_cast<Scalar&>(m_data.value(m_id)); }
+
+    inline int index() const { return m_data.index(m_id); }
+    inline int row() const { return IsColVector ? index() : 0; }
+    inline int col() const { return IsColVector ? 0 : index(); }
+
+    inline operator bool() const { return (m_id < m_end); }
+
+  protected:
+    const CompressedStorage<Scalar>& m_data;
+    int m_id;
+    const int m_end;
+};
+
+#endif // EIGEN_SPARSEVECTOR_H
diff --git a/extern/Eigen2/Eigen/src/Sparse/SuperLUSupport.h b/extern/Eigen2/Eigen/src/Sparse/SuperLUSupport.h
new file mode 100644
index 00000000000..3c9a4fcced6
--- /dev/null
+++ b/extern/Eigen2/Eigen/src/Sparse/SuperLUSupport.h
@@ -0,0 +1,565 @@
+// This file is part of Eigen, a lightweight C++ template library
+// for linear algebra. Eigen itself is part of the KDE project.
+//
+// Copyright (C) 2008-2009 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_SUPERLUSUPPORT_H
+#define EIGEN_SUPERLUSUPPORT_H
+
+// declaration of gssvx taken from GMM++
+#define DECL_GSSVX(NAMESPACE,FNAME,FLOATTYPE,KEYTYPE) \
+    inline float SuperLU_gssvx(superlu_options_t *options, SuperMatrix *A,  \
+         int *perm_c, int *perm_r, int *etree, char *equed,  \
+         FLOATTYPE *R, FLOATTYPE *C, SuperMatrix *L,         \
+         SuperMatrix *U, void *work, int lwork,              \
+         SuperMatrix *B, SuperMatrix *X,                     \
+         FLOATTYPE *recip_pivot_growth,                      \
+         FLOATTYPE *rcond, FLOATTYPE *ferr, FLOATTYPE *berr, \
+         SuperLUStat_t *stats, int *info, KEYTYPE) {         \
+    using namespace NAMESPACE; \
+    mem_usage_t mem_usage;                                    \
+    NAMESPACE::FNAME(options, A, perm_c, perm_r, etree, equed, R, C, L,  \
+         U, work, lwork, B, X, recip_pivot_growth, rcond,    \
+         ferr, berr, &mem_usage, stats, info);               \
+    return mem_usage.for_lu; /* bytes used by the factor storage */     \
+  }
+
+DECL_GSSVX(SuperLU_S,sgssvx,float,float)
+DECL_GSSVX(SuperLU_C,cgssvx,float,std::complex<float>)
+DECL_GSSVX(SuperLU_D,dgssvx,double,double)
+DECL_GSSVX(SuperLU_Z,zgssvx,double,std::complex<double>)
+
+template<typename MatrixType>
+struct SluMatrixMapHelper;
+
+/** \internal
+  *
+  * A wrapper class for SuperLU matrices. It supports only compressed sparse matrices
+  * and dense matrices. Supernodal and other fancy format are not supported by this wrapper.
+  *
+  * This wrapper class mainly aims to avoids the need of dynamic allocation of the storage structure.
+  */
+struct SluMatrix : SuperMatrix
+{
+  SluMatrix()
+  {
+    Store = &storage;
+  }
+
+  SluMatrix(const SluMatrix& other)
+    : SuperMatrix(other)
+  {
+    Store = &storage;
+    storage = other.storage;
+  }
+  
+  SluMatrix& operator=(const SluMatrix& other)
+  {
+    SuperMatrix::operator=(static_cast<const SuperMatrix&>(other));
+    Store = &storage;
+    storage = other.storage;
+    return *this;
+  }
+
+  struct
+  {
+    union {int nnz;int lda;};
+    void *values;
+    int *innerInd;
+    int *outerInd;
+  } storage;
+
+  void setStorageType(Stype_t t)
+  {
+    Stype = t;
+    if (t==SLU_NC || t==SLU_NR || t==SLU_DN)
+      Store = &storage;
+    else
+    {
+      ei_assert(false && "storage type not supported");
+      Store = 0;
+    }
+  }
+
+  template<typename Scalar>
+  void setScalarType()
+  {
+    if (ei_is_same_type<Scalar,float>::ret)
+      Dtype = SLU_S;
+    else if (ei_is_same_type<Scalar,double>::ret)
+      Dtype = SLU_D;
+    else if (ei_is_same_type<Scalar,std::complex<float> >::ret)
+      Dtype = SLU_C;
+    else if (ei_is_same_type<Scalar,std::complex<double> >::ret)
+      Dtype = SLU_Z;
+    else
+    {
+      ei_assert(false && "Scalar type not supported by SuperLU");
+    }
+  }
+
+  template<typename Scalar, int Rows, int Cols, int Options, int MRows, int MCols>
+  static SluMatrix Map(Matrix<Scalar,Rows,Cols,Options,MRows,MCols>& mat)
+  {
+    typedef Matrix<Scalar,Rows,Cols,Options,MRows,MCols> MatrixType;
+    ei_assert( ((Options&RowMajor)!=RowMajor) && "row-major dense matrices is not supported by SuperLU");
+    SluMatrix res;
+    res.setStorageType(SLU_DN);
+    res.setScalarType<Scalar>();
+    res.Mtype     = SLU_GE;
+
+    res.nrow      = mat.rows();
+    res.ncol      = mat.cols();
+
+    res.storage.lda       = mat.stride();
+    res.storage.values    = mat.data();
+    return res;
+  }
+
+  template<typename MatrixType>
+  static SluMatrix Map(SparseMatrixBase<MatrixType>& mat)
+  {
+    SluMatrix res;
+    if ((MatrixType::Flags&RowMajorBit)==RowMajorBit)
+    {
+      res.setStorageType(SLU_NR);
+      res.nrow      = mat.cols();
+      res.ncol      = mat.rows();
+    }
+    else
+    {
+      res.setStorageType(SLU_NC);
+      res.nrow      = mat.rows();
+      res.ncol      = mat.cols();
+    }
+
+    res.Mtype     = SLU_GE;
+
+    res.storage.nnz       = mat.nonZeros();
+    res.storage.values    = mat.derived()._valuePtr();
+    res.storage.innerInd  = mat.derived()._innerIndexPtr();
+    res.storage.outerInd  = mat.derived()._outerIndexPtr();
+
+    res.setScalarType<typename MatrixType::Scalar>();
+
+    // FIXME the following is not very accurate
+    if (MatrixType::Flags & UpperTriangular)
+      res.Mtype = SLU_TRU;
+    if (MatrixType::Flags & LowerTriangular)
+      res.Mtype = SLU_TRL;
+    if (MatrixType::Flags & SelfAdjoint)
+      ei_assert(false && "SelfAdjoint matrix shape not supported by SuperLU");
+    return res;
+  }
+};
+
+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,Options,MRows,MCols> MatrixType;
+  static void run(MatrixType& mat, SluMatrix& res)
+  {
+    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;
+
+    res.nrow      = mat.rows();
+    res.ncol      = mat.cols();
+
+    res.storage.lda       = mat.stride();
+    res.storage.values    = mat.data();
+  }
+};
+
+template<typename Derived>
+struct SluMatrixMapHelper<SparseMatrixBase<Derived> >
+{
+  typedef Derived MatrixType;
+  static void run(MatrixType& mat, SluMatrix& res)
+  {
+    if ((MatrixType::Flags&RowMajorBit)==RowMajorBit)
+    {
+      res.setStorageType(SLU_NR);
+      res.nrow      = mat.cols();
+      res.ncol      = mat.rows();
+    }
+    else
+    {
+      res.setStorageType(SLU_NC);
+      res.nrow      = mat.rows();
+      res.ncol      = mat.cols();
+    }
+
+    res.Mtype     = SLU_GE;
+
+    res.storage.nnz       = mat.nonZeros();
+    res.storage.values    = mat._valuePtr();
+    res.storage.innerInd  = mat._innerIndexPtr();
+    res.storage.outerInd  = mat._outerIndexPtr();
+
+    res.setScalarType<typename MatrixType::Scalar>();
+
+    // FIXME the following is not very accurate
+    if (MatrixType::Flags & UpperTriangular)
+      res.Mtype = SLU_TRU;
+    if (MatrixType::Flags & LowerTriangular)
+      res.Mtype = SLU_TRL;
+    if (MatrixType::Flags & SelfAdjoint)
+      ei_assert(false && "SelfAdjoint matrix shape not supported by SuperLU");
+  }
+};
+
+template<typename Derived>
+SluMatrix SparseMatrixBase<Derived>::asSluMatrix()
+{
+  return SluMatrix::Map(derived());
+}
+
+/** View a Super LU matrix as an Eigen expression */
+template<typename Scalar, int Flags>
+MappedSparseMatrix<Scalar,Flags>::MappedSparseMatrix(SluMatrix& sluMat)
+{
+  if ((Flags&RowMajorBit)==RowMajorBit)
+  {
+    assert(sluMat.Stype == SLU_NR);
+    m_innerSize   = sluMat.ncol;
+    m_outerSize   = sluMat.nrow;
+  }
+  else
+  {
+    assert(sluMat.Stype == SLU_NC);
+    m_innerSize   = sluMat.nrow;
+    m_outerSize   = sluMat.ncol;
+  }
+  m_outerIndex = sluMat.storage.outerInd;
+  m_innerIndices = sluMat.storage.innerInd;
+  m_values = reinterpret_cast<Scalar*>(sluMat.storage.values);
+  m_nnz = sluMat.storage.outerInd[m_outerSize];
+}
+
+template<typename MatrixType>
+class SparseLU<MatrixType,SuperLU> : public SparseLU<MatrixType>
+{
+  protected:
+    typedef SparseLU<MatrixType> Base;
+    typedef typename Base::Scalar Scalar;
+    typedef typename Base::RealScalar RealScalar;
+    typedef Matrix<Scalar,Dynamic,1> Vector;
+    typedef Matrix<int, 1, MatrixType::ColsAtCompileTime> IntRowVectorType;
+    typedef Matrix<int, MatrixType::RowsAtCompileTime, 1> IntColVectorType;
+    typedef SparseMatrix<Scalar,LowerTriangular|UnitDiagBit> LMatrixType;
+    typedef SparseMatrix<Scalar,UpperTriangular> UMatrixType;
+    using Base::m_flags;
+    using Base::m_status;
+
+  public:
+
+    SparseLU(int flags = NaturalOrdering)
+      : Base(flags)
+    {
+    }
+
+    SparseLU(const MatrixType& matrix, int flags = NaturalOrdering)
+      : Base(flags)
+    {
+      compute(matrix);
+    }
+
+    ~SparseLU()
+    {
+    }
+
+    inline const LMatrixType& matrixL() const
+    {
+      if (m_extractedDataAreDirty) extractData();
+      return m_l;
+    }
+
+    inline const UMatrixType& matrixU() const
+    {
+      if (m_extractedDataAreDirty) extractData();
+      return m_u;
+    }
+
+    inline const IntColVectorType& permutationP() const
+    {
+      if (m_extractedDataAreDirty) extractData();
+      return m_p;
+    }
+
+    inline const IntRowVectorType& permutationQ() const
+    {
+      if (m_extractedDataAreDirty) extractData();
+      return m_q;
+    }
+
+    Scalar determinant() const;
+
+    template<typename BDerived, typename XDerived>
+    bool solve(const MatrixBase<BDerived> &b, MatrixBase<XDerived>* x) const;
+
+    void compute(const MatrixType& matrix);
+
+  protected:
+
+    void extractData() const;
+
+  protected:
+    // cached data to reduce reallocation, etc.
+    mutable LMatrixType m_l;
+    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;
+    mutable SluMatrix m_sluB, m_sluX;
+    mutable SuperLUStat_t m_sluStat;
+    mutable superlu_options_t m_sluOptions;
+    mutable std::vector<int> m_sluEtree;
+    mutable std::vector<RealScalar> m_sluRscale, m_sluCscale;
+    mutable std::vector<RealScalar> m_sluFerr, m_sluBerr;
+    mutable char m_sluEqued;
+    mutable bool m_extractedDataAreDirty;
+};
+
+template<typename MatrixType>
+void SparseLU<MatrixType,SuperLU>::compute(const MatrixType& a)
+{
+  const int size = a.rows();
+  m_matrix = a;
+
+  set_default_options(&m_sluOptions);
+  m_sluOptions.ColPerm = NATURAL;
+  m_sluOptions.PrintStat = NO;
+  m_sluOptions.ConditionNumber = NO;
+  m_sluOptions.Trans = NOTRANS;
+  // m_sluOptions.Equil = NO;
+
+  switch (Base::orderingMethod())
+  {
+      case NaturalOrdering          : m_sluOptions.ColPerm = NATURAL; break;
+      case MinimumDegree_AT_PLUS_A  : m_sluOptions.ColPerm = MMD_AT_PLUS_A; break;
+      case MinimumDegree_ATA        : m_sluOptions.ColPerm = MMD_ATA; break;
+      case ColApproxMinimumDegree   : m_sluOptions.ColPerm = COLAMD; break;
+      default:
+        std::cerr << "Eigen: ordering method \"" << Base::orderingMethod() << "\" not supported by the SuperLU backend\n";
+        m_sluOptions.ColPerm = NATURAL;
+  };
+
+  m_sluA = m_matrix.asSluMatrix();
+  memset(&m_sluL,0,sizeof m_sluL);
+  memset(&m_sluU,0,sizeof m_sluU);
+  m_sluEqued = 'B';
+  int info = 0;
+
+  m_p.resize(size);
+  m_q.resize(size);
+  m_sluRscale.resize(size);
+  m_sluCscale.resize(size);
+  m_sluEtree.resize(size);
+
+  RealScalar recip_pivot_gross, rcond;
+  RealScalar ferr, berr;
+
+  // set empty B and X
+  m_sluB.setStorageType(SLU_DN);
+  m_sluB.setScalarType<Scalar>();
+  m_sluB.Mtype = SLU_GE;
+  m_sluB.storage.values = 0;
+  m_sluB.nrow = m_sluB.ncol = 0;
+  m_sluB.storage.lda = size;
+  m_sluX = m_sluB;
+
+  StatInit(&m_sluStat);
+  SuperLU_gssvx(&m_sluOptions, &m_sluA, m_q.data(), m_p.data(), &m_sluEtree[0],
+          &m_sluEqued, &m_sluRscale[0], &m_sluCscale[0],
+          &m_sluL, &m_sluU,
+          NULL, 0,
+          &m_sluB, &m_sluX,
+          &recip_pivot_gross, &rcond,
+          &ferr, &berr,
+          &m_sluStat, &info, Scalar());
+  StatFree(&m_sluStat);
+
+  m_extractedDataAreDirty = true;
+
+  // FIXME how to better check for errors ???
+  Base::m_succeeded = (info == 0);
+}
+
+template<typename MatrixType>
+template<typename BDerived,typename XDerived>
+bool SparseLU<MatrixType,SuperLU>::solve(const MatrixBase<BDerived> &b, MatrixBase<XDerived> *x) const
+{
+  const int size = m_matrix.rows();
+  const int rhsCols = b.cols();
+  ei_assert(size==b.rows());
+
+  m_sluOptions.Fact = FACTORED;
+  m_sluOptions.IterRefine = NOREFINE;
+
+  m_sluFerr.resize(rhsCols);
+  m_sluBerr.resize(rhsCols);
+  m_sluB = SluMatrix::Map(b.const_cast_derived());
+  m_sluX = SluMatrix::Map(x->derived());
+
+  StatInit(&m_sluStat);
+  int info = 0;
+  RealScalar recip_pivot_gross, rcond;
+  SuperLU_gssvx(
+    &m_sluOptions, &m_sluA,
+    m_q.data(), m_p.data(),
+    &m_sluEtree[0], &m_sluEqued,
+    &m_sluRscale[0], &m_sluCscale[0],
+    &m_sluL, &m_sluU,
+    NULL, 0,
+    &m_sluB, &m_sluX,
+    &recip_pivot_gross, &rcond,
+    &m_sluFerr[0], &m_sluBerr[0],
+    &m_sluStat, &info, Scalar());
+  StatFree(&m_sluStat);
+
+  return info==0;
+}
+
+//
+// the code of this extractData() function has been adapted from the SuperLU's Matlab support code,
+//
+//  Copyright (c) 1994 by Xerox Corporation.  All rights reserved.
+//
+//  THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY
+//  EXPRESSED OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
+//
+template<typename MatrixType>
+void SparseLU<MatrixType,SuperLU>::extractData() const
+{
+  if (m_extractedDataAreDirty)
+  {
+    int         upper;
+    int         fsupc, istart, nsupr;
+    int         lastl = 0, lastu = 0;
+    SCformat    *Lstore = static_cast<SCformat*>(m_sluL.Store);
+    NCformat    *Ustore = static_cast<NCformat*>(m_sluU.Store);
+    Scalar      *SNptr;
+
+    const int size = m_matrix.rows();
+    m_l.resize(size,size);
+    m_l.resizeNonZeros(Lstore->nnz);
+    m_u.resize(size,size);
+    m_u.resizeNonZeros(Ustore->nnz);
+
+    int* Lcol = m_l._outerIndexPtr();
+    int* Lrow = m_l._innerIndexPtr();
+    Scalar* Lval = m_l._valuePtr();
+
+    int* Ucol = m_u._outerIndexPtr();
+    int* Urow = m_u._innerIndexPtr();
+    Scalar* Uval = m_u._valuePtr();
+
+    Ucol[0] = 0;
+    Ucol[0] = 0;
+
+    /* for each supernode */
+    for (int k = 0; k <= Lstore->nsuper; ++k)
+    {
+      fsupc   = L_FST_SUPC(k);
+      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)
+      {
+        SNptr = &((Scalar*)Lstore->nzval)[L_NZ_START(j)];
+
+        /* Extract U */
+        for (int i = U_NZ_START(j); i < U_NZ_START(j+1); ++i)
+        {
+          Uval[lastu] = ((Scalar*)Ustore->nzval)[i];
+          /* Matlab doesn't like explicit zero. */
+          if (Uval[lastu] != 0.0)
+            Urow[lastu++] = U_SUB(i);
+        }
+        for (int i = 0; i < upper; ++i)
+        {
+          /* upper triangle in the supernode */
+          Uval[lastu] = SNptr[i];
+          /* Matlab doesn't like explicit zero. */
+          if (Uval[lastu] != 0.0)
+            Urow[lastu++] = L_SUB(istart+i);
+        }
+        Ucol[j+1] = lastu;
+
+        /* Extract L */
+        Lval[lastl] = 1.0; /* unit diagonal */
+        Lrow[lastl++] = L_SUB(istart + upper - 1);
+        for (int i = upper; i < nsupr; ++i)
+        {
+          Lval[lastl] = SNptr[i];
+          /* Matlab doesn't like explicit zero. */
+          if (Lval[lastl] != 0.0)
+            Lrow[lastl++] = L_SUB(istart+i);
+        }
+        Lcol[j+1] = lastl;
+
+        ++upper;
+      } /* for j ... */
+
+    } /* for k ... */
+
+    // squeeze the matrices :
+    m_l.resizeNonZeros(lastl);
+    m_u.resizeNonZeros(lastu);
+
+    m_extractedDataAreDirty = false;
+  }
+}
+
+template<typename MatrixType>
+typename SparseLU<MatrixType,SuperLU>::Scalar SparseLU<MatrixType,SuperLU>::determinant() const
+{
+  if (m_extractedDataAreDirty)
+    extractData();
+
+  // TODO this code coule be moved to the default/base backend
+  // FIXME perhaps we have to take into account the scale factors m_sluRscale and m_sluCscale ???
+  Scalar det = Scalar(1);
+  for (int j=0; j<m_u.cols(); ++j)
+  {
+    if (m_u._outerIndexPtr()[j+1]-m_u._outerIndexPtr()[j] > 0)
+    {
+      int lastId = m_u._outerIndexPtr()[j+1]-1;
+      ei_assert(m_u._innerIndexPtr()[lastId]<=j);
+      if (m_u._innerIndexPtr()[lastId]==j)
+      {
+        det *= m_u._valuePtr()[lastId];
+      }
+    }
+    // std::cout << m_sluRscale[j] << " " << m_sluCscale[j] << "   ";
+  }
+  return det;
+}
+
+#endif // EIGEN_SUPERLUSUPPORT_H
diff --git a/extern/Eigen2/Eigen/src/Sparse/TaucsSupport.h b/extern/Eigen2/Eigen/src/Sparse/TaucsSupport.h
new file mode 100644
index 00000000000..4dddca7b622
--- /dev/null
+++ b/extern/Eigen2/Eigen/src/Sparse/TaucsSupport.h
@@ -0,0 +1,210 @@
+// This file is part of Eigen, a lightweight C++ template library
+// for linear algebra. Eigen itself is part of the KDE project.
+//
+// Copyright (C) 2008-2009 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_TAUCSSUPPORT_H
+#define EIGEN_TAUCSSUPPORT_H
+
+template<typename Derived>
+taucs_ccs_matrix SparseMatrixBase<Derived>::asTaucsMatrix()
+{
+  taucs_ccs_matrix res;
+  res.n         = cols();
+  res.m         = rows();
+  res.flags     = 0;
+  res.colptr    = derived()._outerIndexPtr();
+  res.rowind    = derived()._innerIndexPtr();
+  res.values.v  = derived()._valuePtr();
+  if (ei_is_same_type<Scalar,int>::ret)
+    res.flags |= TAUCS_INT;
+  else if (ei_is_same_type<Scalar,float>::ret)
+    res.flags |= TAUCS_SINGLE;
+  else if (ei_is_same_type<Scalar,double>::ret)
+    res.flags |= TAUCS_DOUBLE;
+  else if (ei_is_same_type<Scalar,std::complex<float> >::ret)
+    res.flags |= TAUCS_SCOMPLEX;
+  else if (ei_is_same_type<Scalar,std::complex<double> >::ret)
+    res.flags |= TAUCS_DCOMPLEX;
+  else
+  {
+    ei_assert(false && "Scalar type not supported by TAUCS");
+  }
+
+  if (Flags & UpperTriangular)
+    res.flags |= TAUCS_UPPER;
+  if (Flags & LowerTriangular)
+    res.flags |= TAUCS_LOWER;
+  if (Flags & SelfAdjoint)
+    res.flags |= (NumTraits<Scalar>::IsComplex ? TAUCS_HERMITIAN : TAUCS_SYMMETRIC);
+  else if ((Flags & UpperTriangular) || (Flags & LowerTriangular))
+    res.flags |= TAUCS_TRIANGULAR;
+
+  return res;
+}
+
+template<typename Scalar, int Flags>
+MappedSparseMatrix<Scalar,Flags>::MappedSparseMatrix(taucs_ccs_matrix& taucsMat)
+{
+  m_innerSize = taucsMat.m;
+  m_outerSize = taucsMat.n;
+  m_outerIndex = taucsMat.colptr;
+  m_innerIndices = taucsMat.rowind;
+  m_values = reinterpret_cast<Scalar*>(taucsMat.values.v);
+  m_nnz = taucsMat.colptr[taucsMat.n];
+}
+
+template<typename MatrixType>
+class SparseLLT<MatrixType,Taucs> : public SparseLLT<MatrixType>
+{
+  protected:
+    typedef SparseLLT<MatrixType> Base;
+    typedef typename Base::Scalar Scalar;
+    typedef typename Base::RealScalar RealScalar;
+    using Base::MatrixLIsDirty;
+    using Base::SupernodalFactorIsDirty;
+    using Base::m_flags;
+    using Base::m_matrix;
+    using Base::m_status;
+
+  public:
+
+    SparseLLT(int flags = 0)
+      : Base(flags), m_taucsSupernodalFactor(0)
+    {
+    }
+
+    SparseLLT(const MatrixType& matrix, int flags = 0)
+      : Base(flags), m_taucsSupernodalFactor(0)
+    {
+      compute(matrix);
+    }
+
+    ~SparseLLT()
+    {
+      if (m_taucsSupernodalFactor)
+        taucs_supernodal_factor_free(m_taucsSupernodalFactor);
+    }
+
+    inline const typename Base::CholMatrixType& matrixL(void) const;
+
+    template<typename Derived>
+    void solveInPlace(MatrixBase<Derived> &b) const;
+
+    void compute(const MatrixType& matrix);
+
+  protected:
+    void* m_taucsSupernodalFactor;
+};
+
+template<typename MatrixType>
+void SparseLLT<MatrixType,Taucs>::compute(const MatrixType& a)
+{
+  if (m_taucsSupernodalFactor)
+  {
+    taucs_supernodal_factor_free(m_taucsSupernodalFactor);
+    m_taucsSupernodalFactor = 0;
+  }
+
+  if (m_flags & IncompleteFactorization)
+  {
+    taucs_ccs_matrix taucsMatA = const_cast<MatrixType&>(a).asTaucsMatrix();
+    taucs_ccs_matrix* taucsRes = taucs_ccs_factor_llt(&taucsMatA, Base::m_precision, 0);
+    // the matrix returned by Taucs is not necessarily sorted,
+    // so let's copy it in two steps
+    DynamicSparseMatrix<Scalar,RowMajor> tmp = MappedSparseMatrix<Scalar>(*taucsRes);
+    m_matrix = tmp;
+    free(taucsRes);
+    m_status = (m_status & ~(CompleteFactorization|MatrixLIsDirty))
+             | IncompleteFactorization
+             | SupernodalFactorIsDirty;
+  }
+  else
+  {
+    taucs_ccs_matrix taucsMatA = const_cast<MatrixType&>(a).asTaucsMatrix();
+    if ( (m_flags & SupernodalLeftLooking)
+      || ((!(m_flags & SupernodalMultifrontal)) && (m_flags & MemoryEfficient)) )
+    {
+      m_taucsSupernodalFactor = taucs_ccs_factor_llt_ll(&taucsMatA);
+    }
+    else
+    {
+      // use the faster Multifrontal routine
+      m_taucsSupernodalFactor = taucs_ccs_factor_llt_mf(&taucsMatA);
+    }
+    m_status = (m_status & ~IncompleteFactorization) | CompleteFactorization | MatrixLIsDirty;
+  }
+}
+
+template<typename MatrixType>
+inline const typename SparseLLT<MatrixType>::CholMatrixType&
+SparseLLT<MatrixType,Taucs>::matrixL() const
+{
+  if (m_status & MatrixLIsDirty)
+  {
+    ei_assert(!(m_status & SupernodalFactorIsDirty));
+
+    taucs_ccs_matrix* taucsL = taucs_supernodal_factor_to_ccs(m_taucsSupernodalFactor);
+
+    // the matrix returned by Taucs is not necessarily sorted,
+    // so let's copy it in two steps
+    DynamicSparseMatrix<Scalar,RowMajor> tmp = MappedSparseMatrix<Scalar>(*taucsL);
+    const_cast<typename Base::CholMatrixType&>(m_matrix) = tmp;
+    free(taucsL);
+    m_status = (m_status & ~MatrixLIsDirty);
+  }
+  return m_matrix;
+}
+
+template<typename MatrixType>
+template<typename Derived>
+void SparseLLT<MatrixType,Taucs>::solveInPlace(MatrixBase<Derived> &b) const
+{
+  bool inputIsCompatibleWithTaucs = (Derived::Flags&RowMajorBit)==0;
+
+  if (!inputIsCompatibleWithTaucs)
+  {
+    matrixL();
+    Base::solveInPlace(b);
+  }
+  else if (m_flags & IncompleteFactorization)
+  {
+    taucs_ccs_matrix taucsLLT = const_cast<typename Base::CholMatrixType&>(m_matrix).asTaucsMatrix();
+    typename ei_plain_matrix_type<Derived>::type x(b.rows());
+    for (int j=0; j<b.cols(); ++j)
+    {
+      taucs_ccs_solve_llt(&taucsLLT,x.data(),&b.col(j).coeffRef(0));
+      b.col(j) = x;
+    }
+  }
+  else
+  {
+    typename ei_plain_matrix_type<Derived>::type x(b.rows());
+    for (int j=0; j<b.cols(); ++j)
+    {
+      taucs_supernodal_solve_llt(m_taucsSupernodalFactor,x.data(),&b.col(j).coeffRef(0));
+      b.col(j) = x;
+    }
+  }
+}
+
+#endif // EIGEN_TAUCSSUPPORT_H
diff --git a/extern/Eigen2/Eigen/src/Sparse/TriangularSolver.h b/extern/Eigen2/Eigen/src/Sparse/TriangularSolver.h
new file mode 100644
index 00000000000..8948ae45e1d
--- /dev/null
+++ b/extern/Eigen2/Eigen/src/Sparse/TriangularSolver.h
@@ -0,0 +1,178 @@
+// 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_SPARSETRIANGULARSOLVER_H
+#define EIGEN_SPARSETRIANGULARSOLVER_H
+
+// forward substitution, row-major
+template<typename Lhs, typename Rhs>
+struct ei_solve_triangular_selector<Lhs,Rhs,LowerTriangular,RowMajor|IsSparse>
+{
+  typedef typename Rhs::Scalar Scalar;
+  static void run(const Lhs& lhs, Rhs& other)
+  {
+    for(int col=0 ; col<other.cols() ; ++col)
+    {
+      for(int i=0; i<lhs.rows(); ++i)
+      {
+        Scalar tmp = other.coeff(i,col);
+        Scalar lastVal = 0;
+        int lastIndex = 0;
+        for(typename Lhs::InnerIterator it(lhs, i); it; ++it)
+        {
+          lastVal = it.value();
+          lastIndex = it.index();
+          tmp -= lastVal * other.coeff(lastIndex,col);
+        }
+        if (Lhs::Flags & UnitDiagBit)
+          other.coeffRef(i,col) = tmp;
+        else
+        {
+          ei_assert(lastIndex==i);
+          other.coeffRef(i,col) = tmp/lastVal;
+        }
+      }
+    }
+  }
+};
+
+// backward substitution, row-major
+template<typename Lhs, typename Rhs>
+struct ei_solve_triangular_selector<Lhs,Rhs,UpperTriangular,RowMajor|IsSparse>
+{
+  typedef typename Rhs::Scalar Scalar;
+  static void run(const Lhs& lhs, Rhs& other)
+  {
+    for(int col=0 ; col<other.cols() ; ++col)
+    {
+      for(int i=lhs.rows()-1 ; i>=0 ; --i)
+      {
+        Scalar tmp = other.coeff(i,col);
+        typename Lhs::InnerIterator it(lhs, i);
+        if (it.index() == i)
+          ++it;
+        for(; it; ++it)
+        {
+          tmp -= it.value() * other.coeff(it.index(),col);
+        }
+
+        if (Lhs::Flags & UnitDiagBit)
+          other.coeffRef(i,col) = tmp;
+        else
+        {
+          typename Lhs::InnerIterator it(lhs, i);
+          ei_assert(it.index() == i);
+          other.coeffRef(i,col) = tmp/it.value();
+        }
+      }
+    }
+  }
+};
+
+// forward substitution, col-major
+template<typename Lhs, typename Rhs>
+struct ei_solve_triangular_selector<Lhs,Rhs,LowerTriangular,ColMajor|IsSparse>
+{
+  typedef typename Rhs::Scalar Scalar;
+  static void run(const Lhs& lhs, Rhs& other)
+  {
+    for(int col=0 ; col<other.cols() ; ++col)
+    {
+      for(int i=0; i<lhs.cols(); ++i)
+      {
+        typename Lhs::InnerIterator it(lhs, i);
+        if(!(Lhs::Flags & UnitDiagBit))
+        {
+          // std::cerr << it.value() << " ; " << it.index() << " == " << i << "\n";
+          ei_assert(it.index()==i);
+          other.coeffRef(i,col) /= it.value();
+        }
+        Scalar tmp = other.coeffRef(i,col);
+        if (it.index()==i)
+          ++it;
+        for(; it; ++it)
+          other.coeffRef(it.index(), col) -= tmp * it.value();
+      }
+    }
+  }
+};
+
+// backward substitution, col-major
+template<typename Lhs, typename Rhs>
+struct ei_solve_triangular_selector<Lhs,Rhs,UpperTriangular,ColMajor|IsSparse>
+{
+  typedef typename Rhs::Scalar Scalar;
+  static void run(const Lhs& lhs, Rhs& other)
+  {
+    for(int col=0 ; col<other.cols() ; ++col)
+    {
+      for(int i=lhs.cols()-1; i>=0; --i)
+      {
+        if(!(Lhs::Flags & UnitDiagBit))
+        {
+          // FIXME lhs.coeff(i,i) might not be always efficient while it must simply be the
+          // last element of the column !
+          other.coeffRef(i,col) /= lhs.coeff(i,i);
+        }
+        Scalar tmp = other.coeffRef(i,col);
+        typename Lhs::InnerIterator it(lhs, i);
+        for(; it && it.index()<i; ++it)
+          other.coeffRef(it.index(), col) -= tmp * it.value();
+      }
+    }
+  }
+};
+
+template<typename Derived>
+template<typename OtherDerived>
+void SparseMatrixBase<Derived>::solveTriangularInPlace(MatrixBase<OtherDerived>& other) const
+{
+  ei_assert(derived().cols() == derived().rows());
+  ei_assert(derived().cols() == other.rows());
+  ei_assert(!(Flags & ZeroDiagBit));
+  ei_assert(Flags & (UpperTriangularBit|LowerTriangularBit));
+
+  enum { copy = ei_traits<OtherDerived>::Flags & RowMajorBit };
+
+  typedef typename ei_meta_if<copy,
+    typename ei_plain_matrix_type_column_major<OtherDerived>::type, OtherDerived&>::ret OtherCopy;
+  OtherCopy otherCopy(other.derived());
+
+  ei_solve_triangular_selector<Derived, typename ei_unref<OtherCopy>::type>::run(derived(), otherCopy);
+
+  if (copy)
+    other = otherCopy;
+}
+
+template<typename Derived>
+template<typename OtherDerived>
+typename ei_plain_matrix_type_column_major<OtherDerived>::type
+SparseMatrixBase<Derived>::solveTriangular(const MatrixBase<OtherDerived>& other) const
+{
+  typename ei_plain_matrix_type_column_major<OtherDerived>::type res(other);
+  solveTriangularInPlace(res);
+  return res;
+}
+
+#endif // EIGEN_SPARSETRIANGULARSOLVER_H
diff --git a/extern/Eigen2/Eigen/src/Sparse/UmfPackSupport.h b/extern/Eigen2/Eigen/src/Sparse/UmfPackSupport.h
new file mode 100644
index 00000000000..b76ffb25248
--- /dev/null
+++ b/extern/Eigen2/Eigen/src/Sparse/UmfPackSupport.h
@@ -0,0 +1,289 @@
+// This file is part of Eigen, a lightweight C++ template library
+// for linear algebra. Eigen itself is part of the KDE project.
+//
+// Copyright (C) 2008-2009 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_UMFPACKSUPPORT_H
+#define EIGEN_UMFPACKSUPPORT_H
+
+/* TODO extract L, extract U, compute det, etc... */
+
+// generic double/complex<double> wrapper functions:
+
+inline void umfpack_free_numeric(void **Numeric, double)
+{ umfpack_di_free_numeric(Numeric); }
+
+inline void umfpack_free_numeric(void **Numeric, std::complex<double>)
+{ umfpack_zi_free_numeric(Numeric); }
+
+inline void umfpack_free_symbolic(void **Symbolic, double)
+{ umfpack_di_free_symbolic(Symbolic); }
+
+inline void umfpack_free_symbolic(void **Symbolic, std::complex<double>)
+{ umfpack_zi_free_symbolic(Symbolic); }
+
+inline int umfpack_symbolic(int n_row,int n_col,
+                            const int Ap[], const int Ai[], const double Ax[], void **Symbolic,
+                            const double Control [UMFPACK_CONTROL], double Info [UMFPACK_INFO])
+{
+  return umfpack_di_symbolic(n_row,n_col,Ap,Ai,Ax,Symbolic,Control,Info);
+}
+
+inline int umfpack_symbolic(int n_row,int n_col,
+                            const int Ap[], const int Ai[], const std::complex<double> Ax[], void **Symbolic,
+                            const double Control [UMFPACK_CONTROL], double Info [UMFPACK_INFO])
+{
+  return umfpack_zi_symbolic(n_row,n_col,Ap,Ai,&Ax[0].real(),0,Symbolic,Control,Info);
+}
+
+inline int umfpack_numeric( const int Ap[], const int Ai[], const double Ax[],
+                            void *Symbolic, void **Numeric,
+                            const double Control[UMFPACK_CONTROL],double Info [UMFPACK_INFO])
+{
+  return umfpack_di_numeric(Ap,Ai,Ax,Symbolic,Numeric,Control,Info);
+}
+
+inline int umfpack_numeric( const int Ap[], const int Ai[], const std::complex<double> Ax[],
+                            void *Symbolic, void **Numeric,
+                            const double Control[UMFPACK_CONTROL],double Info [UMFPACK_INFO])
+{
+  return umfpack_zi_numeric(Ap,Ai,&Ax[0].real(),0,Symbolic,Numeric,Control,Info);
+}
+
+inline int umfpack_solve( int sys, const int Ap[], const int Ai[], const double Ax[],
+                          double X[], const double B[], void *Numeric,
+                          const double Control[UMFPACK_CONTROL], double Info[UMFPACK_INFO])
+{
+  return umfpack_di_solve(sys,Ap,Ai,Ax,X,B,Numeric,Control,Info);
+}
+
+inline int umfpack_solve( int sys, const int Ap[], const int Ai[], const std::complex<double> Ax[],
+                          std::complex<double> X[], const std::complex<double> B[], void *Numeric,
+                          const double Control[UMFPACK_CONTROL], double Info[UMFPACK_INFO])
+{
+  return umfpack_zi_solve(sys,Ap,Ai,&Ax[0].real(),0,&X[0].real(),0,&B[0].real(),0,Numeric,Control,Info);
+}
+
+inline int umfpack_get_lunz(int *lnz, int *unz, int *n_row, int *n_col, int *nz_udiag, void *Numeric, double)
+{
+  return umfpack_di_get_lunz(lnz,unz,n_row,n_col,nz_udiag,Numeric);
+}
+
+inline int umfpack_get_lunz(int *lnz, int *unz, int *n_row, int *n_col, int *nz_udiag, void *Numeric, std::complex<double>)
+{
+  return umfpack_zi_get_lunz(lnz,unz,n_row,n_col,nz_udiag,Numeric);
+}
+
+inline int umfpack_get_numeric(int Lp[], int Lj[], double Lx[], int Up[], int Ui[], double Ux[],
+                               int P[], int Q[], double Dx[], int *do_recip, double Rs[], void *Numeric)
+{
+  return umfpack_di_get_numeric(Lp,Lj,Lx,Up,Ui,Ux,P,Q,Dx,do_recip,Rs,Numeric);
+}
+
+inline int umfpack_get_numeric(int Lp[], int Lj[], std::complex<double> Lx[], int Up[], int Ui[], std::complex<double> Ux[],
+                               int P[], int Q[], std::complex<double> Dx[], int *do_recip, double Rs[], void *Numeric)
+{
+  return umfpack_zi_get_numeric(Lp,Lj,Lx?&Lx[0].real():0,0,Up,Ui,Ux?&Ux[0].real():0,0,P,Q,
+                               Dx?&Dx[0].real():0,0,do_recip,Rs,Numeric);
+}
+
+inline int umfpack_get_determinant(double *Mx, double *Ex, void *NumericHandle, double User_Info [UMFPACK_INFO])
+{
+  return umfpack_di_get_determinant(Mx,Ex,NumericHandle,User_Info);
+}
+
+inline int umfpack_get_determinant(std::complex<double> *Mx, double *Ex, void *NumericHandle, double User_Info [UMFPACK_INFO])
+{
+  return umfpack_zi_get_determinant(&Mx->real(),0,Ex,NumericHandle,User_Info);
+}
+
+
+template<typename MatrixType>
+class SparseLU<MatrixType,UmfPack> : public SparseLU<MatrixType>
+{
+  protected:
+    typedef SparseLU<MatrixType> Base;
+    typedef typename Base::Scalar Scalar;
+    typedef typename Base::RealScalar RealScalar;
+    typedef Matrix<Scalar,Dynamic,1> Vector;
+    typedef Matrix<int, 1, MatrixType::ColsAtCompileTime> IntRowVectorType;
+    typedef Matrix<int, MatrixType::RowsAtCompileTime, 1> IntColVectorType;
+    typedef SparseMatrix<Scalar,LowerTriangular|UnitDiagBit> LMatrixType;
+    typedef SparseMatrix<Scalar,UpperTriangular> UMatrixType;
+    using Base::m_flags;
+    using Base::m_status;
+
+  public:
+
+    SparseLU(int flags = NaturalOrdering)
+      : Base(flags), m_numeric(0)
+    {
+    }
+
+    SparseLU(const MatrixType& matrix, int flags = NaturalOrdering)
+      : Base(flags), m_numeric(0)
+    {
+      compute(matrix);
+    }
+
+    ~SparseLU()
+    {
+      if (m_numeric)
+        umfpack_free_numeric(&m_numeric,Scalar());
+    }
+
+    inline const LMatrixType& matrixL() const
+    {
+      if (m_extractedDataAreDirty) extractData();
+      return m_l;
+    }
+
+    inline const UMatrixType& matrixU() const
+    {
+      if (m_extractedDataAreDirty) extractData();
+      return m_u;
+    }
+
+    inline const IntColVectorType& permutationP() const
+    {
+      if (m_extractedDataAreDirty) extractData();
+      return m_p;
+    }
+
+    inline const IntRowVectorType& permutationQ() const
+    {
+      if (m_extractedDataAreDirty) extractData();
+      return m_q;
+    }
+
+    Scalar determinant() const;
+
+    template<typename BDerived, typename XDerived>
+    bool solve(const MatrixBase<BDerived> &b, MatrixBase<XDerived>* x) const;
+
+    void compute(const MatrixType& matrix);
+
+  protected:
+
+    void extractData() const;
+  
+  protected:
+    // cached data:
+    void* m_numeric;
+    const MatrixType* m_matrixRef;
+    mutable LMatrixType m_l;
+    mutable UMatrixType m_u;
+    mutable IntColVectorType m_p;
+    mutable IntRowVectorType m_q;
+    mutable bool m_extractedDataAreDirty;
+};
+
+template<typename MatrixType>
+void SparseLU<MatrixType,UmfPack>::compute(const MatrixType& a)
+{
+  const int rows = a.rows();
+  const int cols = a.cols();
+  ei_assert((MatrixType::Flags&RowMajorBit)==0 && "Row major matrices are not supported yet");
+
+  m_matrixRef = &a;
+
+  if (m_numeric)
+    umfpack_free_numeric(&m_numeric,Scalar());
+
+  void* symbolic;
+  int errorCode = 0;
+  errorCode = umfpack_symbolic(rows, cols, a._outerIndexPtr(), a._innerIndexPtr(), a._valuePtr(),
+                                  &symbolic, 0, 0);
+  if (errorCode==0)
+    errorCode = umfpack_numeric(a._outerIndexPtr(), a._innerIndexPtr(), a._valuePtr(),
+                                   symbolic, &m_numeric, 0, 0);
+
+  umfpack_free_symbolic(&symbolic,Scalar());
+
+  m_extractedDataAreDirty = true;
+
+  Base::m_succeeded = (errorCode==0);
+}
+
+template<typename MatrixType>
+void SparseLU<MatrixType,UmfPack>::extractData() const
+{
+  if (m_extractedDataAreDirty)
+  {
+    // get size of the data
+    int lnz, unz, rows, cols, nz_udiag;
+    umfpack_get_lunz(&lnz, &unz, &rows, &cols, &nz_udiag, m_numeric, Scalar());
+
+    // allocate data
+    m_l.resize(rows,std::min(rows,cols));
+    m_l.resizeNonZeros(lnz);
+    
+    m_u.resize(std::min(rows,cols),cols);
+    m_u.resizeNonZeros(unz);
+
+    m_p.resize(rows);
+    m_q.resize(cols);
+
+    // extract
+    umfpack_get_numeric(m_l._outerIndexPtr(), m_l._innerIndexPtr(), m_l._valuePtr(),
+                        m_u._outerIndexPtr(), m_u._innerIndexPtr(), m_u._valuePtr(),
+                        m_p.data(), m_q.data(), 0, 0, 0, m_numeric);
+    
+    m_extractedDataAreDirty = false;
+  }
+}
+
+template<typename MatrixType>
+typename SparseLU<MatrixType,UmfPack>::Scalar SparseLU<MatrixType,UmfPack>::determinant() const
+{
+  Scalar det;
+  umfpack_get_determinant(&det, 0, m_numeric, 0);
+  return det;
+}
+
+template<typename MatrixType>
+template<typename BDerived,typename XDerived>
+bool SparseLU<MatrixType,UmfPack>::solve(const MatrixBase<BDerived> &b, MatrixBase<XDerived> *x) const
+{
+  //const int size = m_matrix.rows();
+  const int rhsCols = b.cols();
+//   ei_assert(size==b.rows());
+  ei_assert((BDerived::Flags&RowMajorBit)==0 && "UmfPack backend does not support non col-major rhs yet");
+  ei_assert((XDerived::Flags&RowMajorBit)==0 && "UmfPack backend does not support non col-major result yet");
+
+  int errorCode;
+  for (int j=0; j<rhsCols; ++j)
+  {
+    errorCode = umfpack_solve(UMFPACK_A,
+        m_matrixRef->_outerIndexPtr(), m_matrixRef->_innerIndexPtr(), m_matrixRef->_valuePtr(),
+        &x->col(j).coeffRef(0), &b.const_cast_derived().col(j).coeffRef(0), m_numeric, 0, 0);
+    if (errorCode!=0)
+      return false;
+  }
+//   errorCode = umfpack_di_solve(UMFPACK_A,
+//       m_matrixRef._outerIndexPtr(), m_matrixRef._innerIndexPtr(), m_matrixRef._valuePtr(),
+//       x->derived().data(), b.derived().data(), m_numeric, 0, 0);
+
+  return true;
+}
+
+#endif // EIGEN_UMFPACKSUPPORT_H