diff --git a/.gitattributes b/.gitattributes
index 018131673f6..e1f146d5aa9 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -3436,6 +3436,14 @@ Snap_rounding_2/doc_tex/Snap_rounding_2/sr1.pdf -text svneol=unset#application/p
 Snap_rounding_2/test/Snap_rounding_2/cgal_test eol=lf
 Snap_rounding_2/test/Snap_rounding_2/cgal_test_base -text
 Snap_rounding_2/test/Snap_rounding_2/cgal_test_with_cmake eol=lf
+Solver_interface/include/CGAL/Eigen_matrix.h -text
+Solver_interface/include/CGAL/Eigen_solver_traits.h -text
+Solver_interface/include/CGAL/Eigen_svd.h -text
+Solver_interface/include/CGAL/Eigen_vector.h -text
+Solver_interface/package_info/Solver_interface/copyright -text
+Solver_interface/package_info/Solver_interface/description.txt -text
+Solver_interface/package_info/Solver_interface/license.txt -text
+Solver_interface/package_info/Solver_interface/maintainer -text
 Spatial_searching/benchmark/Spatial_searching/Compare_ANN_STANN_CGAL.cpp -text
 Spatial_searching/demo/Spatial_searching/Qt3/help/index.html svneol=native#text/html
 Spatial_searching/doc_tex/Spatial_searching/Fig1.gif -text svneol=unset#image/gif
diff --git a/Solver_interface/include/CGAL/Eigen_matrix.h b/Solver_interface/include/CGAL/Eigen_matrix.h
new file mode 100644
index 00000000000..ac04da4a986
--- /dev/null
+++ b/Solver_interface/include/CGAL/Eigen_matrix.h
@@ -0,0 +1,230 @@
+// Copyright (c) 2012  INRIA Bordeaux Sud-Ouest (France), All rights reserved.
+//
+// This file is part of CGAL (www.cgal.org); 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.
+//
+// Licensees holding a valid commercial license may use this file in
+// accordance with the commercial license agreement provided with the software.
+//
+// This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
+// WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+//
+// $URL$
+// $Id$
+//
+// Author(s)     : Gael Guennebaud
+
+#ifndef CGAL_EIGEN_MATRIX_H
+#define CGAL_EIGEN_MATRIX_H
+
+#include <CGAL/basic.h> // include basic.h before testing #defines
+
+#define EIGEN_YES_I_KNOW_SPARSE_MODULE_IS_NOT_STABLE_YET
+#include <Eigen/Sparse>
+
+namespace CGAL {
+
+
+/// The class Eigen_sparse_matrix
+/// is a C++ wrapper around Eigen' matrix type SparseMatrix<>.
+///
+/// This kind of matrix can be either symmetric or not. Symmetric
+/// matrices store only the lower triangle.
+///
+/// @heading Is Model for the Concepts: Model of the SparseLinearAlgebraTraits_d::Matrix concept.
+///
+/// @heading Parameters:
+/// @param T Number type.
+
+template<class T>
+struct Eigen_sparse_matrix
+{
+// Public types
+public:
+
+  typedef Eigen::SparseMatrix<T> EigenType;
+  typedef T NT;
+
+// Public operations
+public:
+
+  /// Create a square matrix initialized with zeros.
+  Eigen_sparse_matrix(int  dim,                   ///< Matrix dimension.
+                      bool is_symmetric = false)  ///< Symmetric/hermitian?
+    : m_matrix(dim,dim)
+  {
+    CGAL_precondition(dim > 0);
+
+    m_is_symmetric = is_symmetric;
+    
+    // reserve memory for a regular 3D grid
+    m_matrix.reserve(Eigen::VectorXi::Constant(m_matrix.outerSize(), 27));
+  }
+
+  /// Create a rectangular matrix initialized with zeros.
+  ///
+  /// @commentheading Precondition: rows == columns if is_symmetric is true.
+  Eigen_sparse_matrix(int  rows,                 ///< Number of rows.
+                      int  columns,              ///< Number of columns.
+                      bool is_symmetric = false) ///< Symmetric/hermitian?
+    : m_matrix(rows,columns)
+  {
+    CGAL_precondition(rows > 0);
+    CGAL_precondition(columns > 0);
+    if (m_is_symmetric) {
+        CGAL_precondition(rows == columns);
+    }
+
+    m_is_symmetric = is_symmetric;
+    
+    // reserve memory for a regular 3D grid
+    m_matrix.reserve(Eigen::VectorXi::Constant(m_matrix.outerSize(), 27));
+  }
+
+  /// Delete this object and the wrapped TAUCS matrix.
+  ~Eigen_sparse_matrix()
+  {
+  }
+
+  /// Return the matrix number of rows
+  int row_dimension() const    { return m_matrix.rows(); }
+  /// Return the matrix number of columns
+  int column_dimension() const { return m_matrix.cols(); }
+
+
+  /// Write access to a matrix coefficient: a_ij <- val.
+  ///
+  /// Optimizations:
+  /// - For symmetric matrices, Eigen_sparse_matrix stores only the lower triangle
+  ///   set_coef() does nothing if (i, j) belongs to the upper triangle.
+  /// - Caller can optimize this call by setting 'new_coef' to true
+  ///   if the coefficient does not already exist in the matrix.
+  ///
+  /// @commentheading Preconditions:
+  /// - 0 <= i < row_dimension().
+  /// - 0 <= j < column_dimension().
+  void set_coef(int i, int j, T  val, bool new_coef = false)
+  {
+    CGAL_precondition(i < row_dimension());
+    CGAL_precondition(j < column_dimension());
+
+    if (m_is_symmetric && (j > i))
+      return;
+
+    if(new_coef)  m_matrix.insert(i,j)   = val;
+    else          m_matrix.coeffRef(i,j) = val;
+  }
+
+  /// Write access to a matrix coefficient: a_ij <- a_ij+val.
+  ///
+  /// Optimizations:
+  /// - For symmetric matrices, Eigen_sparse_matrix stores only the lower triangle
+  ///   add_coef() does nothing if (i, j) belongs to the upper triangle.
+  ///
+  /// @commentheading Preconditions:
+  /// - 0 <= i < row_dimension().
+  /// - 0 <= j < column_dimension().
+  void add_coef(int i, int j, T  val)
+  {
+    CGAL_precondition(i < row_dimension());
+    CGAL_precondition(j < column_dimension());
+
+    if (m_is_symmetric && (j > i))
+      return;
+
+    m_matrix.coeffRef(i,j) += val;
+  }  
+  
+
+
+  const EigenType& eigen_object() const
+  {
+    // turns the matrix into compressed mode:
+    //  -> release some memory
+    //  -> required for some external solvers
+    m_matrix.makeCompressed();
+    return m_matrix;
+  }
+
+private:
+
+
+  /// Eigen_sparse_matrix cannot be copied (yet)
+  Eigen_sparse_matrix(const Eigen_sparse_matrix& rhs);
+  Eigen_sparse_matrix& operator=(const Eigen_sparse_matrix& rhs);
+
+// Fields
+private:
+
+  mutable EigenType m_matrix;
+
+  // Symmetric/hermitian?
+  bool m_is_symmetric;
+
+}; // Eigen_sparse_matrix
+
+
+
+/// The class Eigen_sparse_symmetric_matrix is a C++ wrapper
+/// around a Eigen sparse matrix (type Eigen::SparseMatrix).
+///
+/// Symmetric matrices store only the lower triangle.
+///
+/// @heading Is Model for the Concepts: Model of the SparseLinearAlgebraTraits_d::Matrix concept.
+///
+/// @heading Parameters:
+/// @param T Number type.
+
+template<class T>
+struct Eigen_sparse_symmetric_matrix
+  : public Eigen_sparse_matrix<T>
+{
+// Public types
+  typedef T NT;
+
+// Public operations
+
+  /// Create a square *symmetric* matrix initialized with zeros.
+  Eigen_sparse_symmetric_matrix(int  dim)                  ///< Matrix dimension.
+      : Eigen_sparse_matrix<T>(dim, true /* symmetric */)
+  {
+  }
+
+  /// Create a square *symmetric* matrix initialized with zeros.
+  ///
+  /// @commentheading Precondition: rows == columns.
+  Eigen_sparse_symmetric_matrix(int  rows,                 ///< Number of rows.
+                                int  columns)              ///< Number of columns.
+    : Eigen_sparse_matrix<T>(rows, columns, true /* symmetric */)
+  {
+  }
+};
+
+template <class FT>
+struct Eigen_matrix : public ::Eigen::Matrix<FT,::Eigen::Dynamic,::Eigen::Dynamic>
+{
+  typedef ::Eigen::Matrix<FT,::Eigen::Dynamic,::Eigen::Dynamic> EigenType;
+  
+  Eigen_matrix( std::size_t n1, std::size_t n2):EigenType(n1,n2){}
+  
+  std::size_t number_of_rows () const {return this->rows();}
+  
+  std::size_t number_of_columns () const {return this->cols();}
+  
+  FT operator()( std::size_t i , std::size_t j ) const {return this->operator()(i,j);}
+  
+  void set( std::size_t i, std::size_t j,FT value){
+    this->coeffRef(i,j)=value;
+  }
+
+  const EigenType& eigen_object() const{
+    return static_cast<const EigenType&>(*this);
+  }
+
+};
+
+} //namespace CGAL
+
+#endif // CGAL_EIGEN_MATRIX_H
diff --git a/Solver_interface/include/CGAL/Eigen_solver_traits.h b/Solver_interface/include/CGAL/Eigen_solver_traits.h
new file mode 100644
index 00000000000..bb96dade078
--- /dev/null
+++ b/Solver_interface/include/CGAL/Eigen_solver_traits.h
@@ -0,0 +1,102 @@
+// Copyright (c) 2012  INRIA Bordeaux Sud-Ouest (France), All rights reserved.
+//
+// This file is part of CGAL (www.cgal.org); 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.
+//
+// Licensees holding a valid commercial license may use this file in
+// accordance with the commercial license agreement provided with the software.
+//
+// This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
+// WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+//
+// $URL$
+// $Id$
+//
+// Author(s)     : Gael Guennebaud
+
+#ifndef CGAL_EIGEN_SOLVER_TRAITS_H
+#define CGAL_EIGEN_SOLVER_TRAITS_H
+
+#include <CGAL/basic.h> // include basic.h before testing #defines
+
+#include <Eigen/Sparse>
+#include <CGAL/Eigen_matrix.h>
+#include <CGAL/Eigen_vector.h>
+
+namespace CGAL {
+
+
+namespace internal {
+  template <class EigenSolver,class FT>
+  struct Get_eigen_matrix{
+    typedef Eigen_sparse_matrix<FT> type;
+  };
+  
+  template <class FT,class EigenMatrix>
+  struct Get_eigen_matrix< ::Eigen::ConjugateGradient<EigenMatrix>,FT>{
+    typedef Eigen_sparse_symmetric_matrix<FT> type;
+  };
+
+  template <class FT,class EigenMatrix>
+  struct Get_eigen_matrix< ::Eigen::SimplicialCholesky<EigenMatrix>,FT>{
+    typedef Eigen_sparse_symmetric_matrix<FT> type;
+  };
+} //internal 
+  
+/// The class Eigen_solver_traits
+/// is a generic traits class for solving asymmetric or symmetric positive definite (SPD)
+/// sparse linear systems using one of the Eigen solvers.
+/// The default solver is the iterative bi-congugate gradient stabilized solver
+/// Eigen::BiCGSTAB for double.
+///
+/// @heading Is Model for the Concepts: Model of the SparseLinearAlgebraTraits_d concept.
+
+template<class EigenSolverT = Eigen::BiCGSTAB<Eigen_sparse_matrix<double>::EigenType> >
+class Eigen_solver_traits
+{
+  typedef typename EigenSolverT::Scalar Scalar;
+// Public types
+public:
+   typedef Scalar                                                       NT;
+   typedef typename internal::Get_eigen_matrix<EigenSolverT,NT>::type   Matrix;
+   typedef Eigen_vector<Scalar>                                         Vector;
+   
+
+// Public operations
+public:
+
+   Eigen_solver_traits()
+   {
+   }
+   
+   EigenSolverT& solver() { return m_solver; }
+
+   /// Solve the sparse linear system "A*X = B".
+   /// Return true on success. The solution is then (1/D) * X.
+   ///
+   /// @commentheading Preconditions:
+   /// - A.row_dimension()    == B.dimension().
+   /// - A.column_dimension() == X.dimension().
+   bool linear_solver(const Matrix& A, const Vector& B, Vector& X, NT& D)
+   {
+      D = 1;          // Eigen does not support homogeneous coordinates
+
+      m_solver.compute(A.eigen_object());
+       
+      if(m_solver.info() != Eigen::Success)
+         return false;
+         
+      X = m_solver.solve(B);
+
+      return m_solver.info() == Eigen::Success;
+   }
+protected:
+  EigenSolverT m_solver;
+
+};
+
+} //namespace CGAL
+
+#endif // CGAL_EIGEN_SOLVER_TRAITS_H
diff --git a/Solver_interface/include/CGAL/Eigen_svd.h b/Solver_interface/include/CGAL/Eigen_svd.h
new file mode 100644
index 00000000000..e35f8e8d7e0
--- /dev/null
+++ b/Solver_interface/include/CGAL/Eigen_svd.h
@@ -0,0 +1,46 @@
+// Copyright (c) 2012  INRIA Bordeaux Sud-Ouest (France), All rights reserved.
+//
+// This file is part of CGAL (www.cgal.org); 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.
+//
+// Licensees holding a valid commercial license may use this file in
+// accordance with the commercial license agreement provided with the software.
+//
+// This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
+// WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+//
+// $URL$
+// $Id$
+//
+// Author(s)     : Gael Guennebaud
+
+#ifndef CGAL_EIGEN_SVD_H
+#define CGAL_EIGEN_SVD_H
+
+#include <CGAL/Eigen_matrix.h>
+#include <CGAL/Eigen_vector.h>
+#include <Eigen/SVD>
+
+
+
+namespace CGAL {
+
+class Eigen_svd{
+public:
+  typedef double FT;
+  typedef Eigen_vector<FT> Vector;
+  typedef Eigen_matrix<FT> Matrix;
+  //solve MX=B using SVD and return the condition number of M
+  //The solution is stored in B
+  static FT solve(const Matrix& M, Vector& B){
+    Eigen::JacobiSVD<Matrix::EigenType> jacobiSvd(M.eigen_object(),::Eigen::ComputeThinU | ::Eigen::ComputeThinV);
+    B.eigen_object()=jacobiSvd.solve(Vector::EigenType(B.eigen_object()));
+    return jacobiSvd.singularValues().array().abs().maxCoeff()/
+           jacobiSvd.singularValues().array().abs().minCoeff();
+  }
+};
+
+}//namespace CGAL
+#endif // CGAL_EIGEN_SVD_H
diff --git a/Solver_interface/include/CGAL/Eigen_vector.h b/Solver_interface/include/CGAL/Eigen_vector.h
new file mode 100644
index 00000000000..dd5c1ad9b6d
--- /dev/null
+++ b/Solver_interface/include/CGAL/Eigen_vector.h
@@ -0,0 +1,96 @@
+// Copyright (c) 2012  INRIA Bordeaux Sud-Ouest (France), All rights reserved.
+//
+// This file is part of CGAL (www.cgal.org); 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.
+//
+// Licensees holding a valid commercial license may use this file in
+// accordance with the commercial license agreement provided with the software.
+//
+// This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
+// WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+//
+// $URL$
+// $Id$
+//
+// Author(s)     : Gael Guennebaud
+
+#ifndef CGAL_EIGEN_VECTOR_H
+#define CGAL_EIGEN_VECTOR_H
+
+#include <CGAL/basic.h> // include basic.h before testing #defines
+
+#include <Eigen/Core>
+
+namespace CGAL {
+
+/// The class Eigen_vector
+/// is a C++ wrapper around Eigen' dense vector type Matrix<T,Dynamic,1>.
+///
+/// @heading Is Model for the Concepts: Model of the SparseLinearAlgebraTraits_d::Vector concept.
+
+template<class T> 
+class Eigen_vector : public Eigen::Matrix<T,Eigen::Dynamic,1>
+{
+// Public types
+public:
+
+   typedef T NT;
+   typedef Eigen::Matrix<T,Eigen::Dynamic,1> EigenType;
+
+// Public operations
+public:
+
+  Eigen_vector<T>& operator=(const Eigen_vector<T>& other){
+    return static_cast<EigenType&>(*this) = other.eigen_object();
+  }
+
+  Eigen_vector<T>& operator=(const EigenType& other){
+    return 
+      static_cast<Eigen_vector<T>&>(
+        static_cast<EigenType&>(*this) = other
+    );
+  }
+
+   /// Create a vector initialized with zeros.
+   Eigen_vector(int dimension)
+     : EigenType(dimension)
+   {
+     this->setZero();
+   }
+
+   /// Copy constructor.
+   Eigen_vector(const Eigen_vector& toCopy)
+     : EigenType(toCopy)
+   {
+   }
+
+   ~Eigen_vector()
+   {
+   }
+
+   /// Return the vector's number of coefficients.
+   int dimension() const {
+       return this->size();
+   }
+
+   /// Get TAUCS vector wrapped by this object.
+   const EigenType& eigen_object() const {
+       return *this;
+   }
+   EigenType& eigen_object() {
+       return *this;
+   }
+   
+   void set(int i,NT value) {
+     this->operator[](i)=value;
+   }
+   
+   NT* vector() {return this->data();}
+   
+};
+
+} //namespace CGAL
+
+#endif // CGAL_EIGEN_VECTOR_H
diff --git a/Solver_interface/package_info/Solver_interface/copyright b/Solver_interface/package_info/Solver_interface/copyright
new file mode 100644
index 00000000000..a510ca9b8ec
--- /dev/null
+++ b/Solver_interface/package_info/Solver_interface/copyright
@@ -0,0 +1 @@
+INRIA Bordeaux Sud-Ouest (France)
diff --git a/Solver_interface/package_info/Solver_interface/description.txt b/Solver_interface/package_info/Solver_interface/description.txt
new file mode 100644
index 00000000000..b934d65f214
--- /dev/null
+++ b/Solver_interface/package_info/Solver_interface/description.txt
@@ -0,0 +1,2 @@
+Solver_interface: contains classes to interface third party linear algebra solvers
+to CGAL (such as Eigen for example)
diff --git a/Solver_interface/package_info/Solver_interface/license.txt b/Solver_interface/package_info/Solver_interface/license.txt
new file mode 100644
index 00000000000..0b91802ccd4
--- /dev/null
+++ b/Solver_interface/package_info/Solver_interface/license.txt
@@ -0,0 +1 @@
+LGPL (v3 or later) 
diff --git a/Solver_interface/package_info/Solver_interface/maintainer b/Solver_interface/package_info/Solver_interface/maintainer
new file mode 100644
index 00000000000..5f89db128de
--- /dev/null
+++ b/Solver_interface/package_info/Solver_interface/maintainer
@@ -0,0 +1,2 @@
+Gael.Guennebaud <Gael.Guennebaud@inria.fr>
+Sebastien Loriot <sloriot.ml@gmail.com>