text: // --------------------------------------------------------------------------
  //                   OpenMS -- Open-Source Mass Spectrometry
  // --------------------------------------------------------------------------
  // Copyright The OpenMS Team -- Eberhard Karls University Tuebingen,
  // ETH Zurich, and Freie Universitaet Berlin 2002-2021.
  //
  // This software is released under a three-clause BSD license:
  //  * Redistributions of source code must retain the above copyright
  //    notice, this list of conditions and the following disclaimer.
  //  * Redistributions in binary form must reproduce the above copyright
  //    notice, this list of conditions and the following disclaimer in the
  //    documentation and/or other materials provided with the distribution.
  //  * Neither the name of any author or any participating institution
  //    may be used to endorse or promote products derived from this software
  //    without specific prior written permission.
  // For a full list of authors, refer to the file AUTHORS.
  // --------------------------------------------------------------------------
  // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  // AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  // IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  // ARE DISCLAIMED. IN NO EVENT SHALL ANY OF THE AUTHORS OR THE CONTRIBUTING
  // INSTITUTIONS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  // EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  // PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
  // OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  // WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  // OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  // ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  //
  // --------------------------------------------------------------------------
  // $Maintainer: Timo Sachsenberg $
  // $Authors: Christian Ehrlich $
  // --------------------------------------------------------------------------
  
  #pragma once
  
  #include <OpenMS/DATASTRUCTURES/Matrix.h>
  
  #include <Eigen/Core>
  
  #include <boost/shared_ptr.hpp>
  
  namespace OpenMS
  {
    /** Matrix utility functions.
     *
     */
  
    typedef boost::shared_ptr< const Eigen::MatrixXd > EigenMatrixXdPtr;
    typedef boost::shared_ptr< Eigen::MatrixXd > MutableEigenMatrixXdPtr;
  
    static EigenMatrixXdPtr
    convertOpenMSMatrix2EigenMatrixXd( const Matrix<double>& m )
    {
      MutableEigenMatrixXdPtr em ( new Eigen::MatrixXd(m.rows(), m.cols()) );
      for (unsigned i=0; i<m.rows(); ++i)
      {
        for (unsigned j=0; j<m.cols(); ++j)
        {
          (*em)(i,j) = m(i,j);
        }
      }
      return em;
    }
  
    static bool
    matrixIsIdentityMatrix(const Matrix<double>& channel_frequency)
    {
      for (Matrix<double>::SizeType i = 0; i < channel_frequency.rows(); ++i)
      {
        for (Matrix<double>::SizeType j = 0; j < channel_frequency.rows(); ++j)
        {
          // check if the entries are those of a identity matrix;
          // i==j -> m(i,j) == 1.0 && i!=j -> m(i,j) == 0.0
          if ((i == j && channel_frequency(i, j) != 1.0) || channel_frequency(i, j) != 0.0)
          {
            return false;
          }
        }
      }
      return true;
    }
  }//namespace
  
  