anchor.diff:  
   contains
   
  +    !   \brief Make banded matrix from a row. Banded matrix representation corresponds to BLAS-2 documentation. Memory
  +    !   usage O(nm), time complexity O(nm).
  +    !
  +    !   \param[in] n
  +    !   \verbatim
  +    !       Size of square banded matrix `mat`.
  +    !   \endverbatim
  +    !
  +    !   \param[in] m
  +    !   \verbatim
  +    !       Length of `row`.
  +    !   \endverbatim
  +    !
  +    !   \param[in] row
  +    !   \verbatim
  +    !       Row that composes banded matrix.
  +    !   \endverbatim
  +    !
  +    !   \param[out] mat
  +    !   \verbatim
  +    !       Banded matrix as a Fortran array of shape (m, n).
  +    !   \endverbatim
       pure subroutine make_banded_matrix(n, m, row, mat)        
           implicit none
   
  
positive.code:         r = coeffs(12) * pumping  / (coeffs(13) + coeffs(14) * u_sqr)
      end subroutine
  
      subroutine hamiltonian(pumping, coeffs, u, v, op, klu, n)
          implicit none
  
  
negative.code:         end do
      end subroutine runge_kutta
  
      !   \brief Solve Non-Linear Schrodinger equation in axial symmentric geometry. It is based on Runge-Kutta method of
      !   order 4 with laplacian approximation order that passed as argument. Initial solution is uniform everywhere on
      !   the grid.
      !
      !   \param[in] dt
      !   \verbatim
  