text: // This file is part of Eigen, a lightweight C++ template library
  // for linear algebra.
  //
  // Copyright (C) 2008-2014 Gael Guennebaud <gael.guennebaud@inria.fr>
  //
  // This Source Code Form is subject to the terms of the Mozilla
  // Public License v. 2.0. If a copy of the MPL was not distributed
  // with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
  
  #ifndef EIGEN_SPARSEREDUX_H
  #define EIGEN_SPARSEREDUX_H
  
  namespace Eigen { 
  
  template<typename Derived>
  typename internal::traits<Derived>::Scalar
  SparseMatrixBase<Derived>::sum() const
  {
    eigen_assert(rows()>0 && cols()>0 && "you are using a non initialized matrix");
    Scalar res(0);
    internal::evaluator<Derived> thisEval(derived());
    for (Index j=0; j<outerSize(); ++j)
      for (typename internal::evaluator<Derived>::InnerIterator iter(thisEval,j); iter; ++iter)
        res += iter.value();
    return res;
  }
  
  template<typename _Scalar, int _Options, typename _Index>
  typename internal::traits<SparseMatrix<_Scalar,_Options,_Index> >::Scalar
  SparseMatrix<_Scalar,_Options,_Index>::sum() const
  {
    eigen_assert(rows()>0 && cols()>0 && "you are using a non initialized matrix");
    if(this->isCompressed())
      return Matrix<Scalar,1,Dynamic>::Map(m_data.valuePtr(), m_data.size()).sum();
    else
      return Base::sum();
  }
  
  template<typename _Scalar, int _Options, typename _Index>
  typename internal::traits<SparseVector<_Scalar,_Options, _Index> >::Scalar
  SparseVector<_Scalar,_Options,_Index>::sum() const
  {
    eigen_assert(rows()>0 && cols()>0 && "you are using a non initialized matrix");
    return Matrix<Scalar,1,Dynamic>::Map(m_data.valuePtr(), m_data.size()).sum();
  }
  
  } // end namespace Eigen
  
  #endif // EIGEN_SPARSEREDUX_H
  