message: Sort sparse matrix element in the correct order
diff: @@ -39,15 +39,13 @@ rtk::MatlabSparseMatrix::MatlabSparseMatrix(const vnl_sparse_matrix<double>& spa
  unsigned int indexColumn = idx[0] + idx[2]*output->GetLargestPossibleRegion().GetSize()[2];
  sparseMatrixColumn::iterator it = columnsVector[indexColumn].begin();
  while (it != columnsVector[indexColumn].end()) {
  - if (sparseMatrix.getrow() > it->first)
  + if (sparseMatrix.getrow() < it->first)
  break;
  ++it;
  }
  columnsVector[indexColumn].insert(it, std::make_pair(sparseMatrix.getrow(),sparseMatrix.value()));
  ++nonZeroElement;
  }
  - for (unsigned int i=0; i<nbColumn; ++i)
  - std::reverse(columnsVector[i].begin(),columnsVector[i].end());
  //Store the sparse matrix into a matlab structure
  std::string headerMatlab("MATLAB 5.0 MAT-file, Platform: GLNXA64, Created on: Fri May 18 14:11:56 2018 ");
  