anchor.diff:          real(dp), intent(in) :: nn, nion, temperature
           type(composition_info_type), intent(in) :: ionic
           integer, intent(out) :: ierr
  +        real(dp) :: nu      ! neutron-impurity scattering frequency
  +
  +        integer, parameter :: num_integration_variables = 1
  +        integer, parameter :: num_ipar = 0
  +        integer, parameter :: num_rpar = 6
       
           real(dp) :: ne      ! number density of electrons
           real(dp) :: kFn     ! neutron Fermi wavevector 
           real(dp) :: EFn     ! neutron Fermi energy
  -        real(dp) :: nu      ! neutron-impurity scattering frequency
           real(dp) :: V       ! effective neutron-impurity potential 
           real(dp) :: Lambda_n_imp    ! Coulomb logarithm (Potekhin et al. 1999)
           real(dp) :: fac, sf_frac, Tc, xFn
  
positive.code:         rpar(5) = kfn
          rpar(6) = R_a
  
          call dop853(n,structure_factor_impurity,kn_start,y,kn_end,h, &
          &   int_default_max_step_size,int_default_max_steps, &
          & rtol,atol,itol, null_solout, iout, work, lwork, iwork, liwork,  &
          &   num_rpar, rpar, num_ipar, ipar, lout, idid)
  
          if (idid < 0) then
  
negative.code:         rpar(5) = kfn
          rpar(6) = R_a
  
          call dop853(num_integration_variables, &
          &   structure_factor_phonon,kn_start,y,kn_end,h, &
          &   int_default_max_step_size,int_default_max_steps, &
          &   rtol,atol,itol, null_solout, iout, work, lwork, iwork, liwork,  &
          &   num_rpar, rpar, num_ipar, ipar, lout, idid)
  