text: // 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
  