constraint_eqn_092 Subroutine

   subroutine constraint_eqn_092(tmp_cc, tmp_con, tmp_err, tmp_symbol, tmp_units)
      !! Equation for checking is D/T ratio is consistent, and sums to 1.
      !! author: G Turkington, UKAEA
      !! args : output structure : residual error; constraint value;
      !! residual error in physical units; output string; units string
      !! f_deuterium : input : fraction of deuterium ions
      !! f_tritium  : input : fraction of tritium ions
      !! f_helium3  : input : fraction of helium-3 ions
      use physics_variables, only: f_deuterium, f_tritium, f_helium3
      implicit none
      real(dp), intent(out) :: tmp_cc
      real(dp), intent(out) :: tmp_con
      real(dp), intent(out) :: tmp_err
      character(len=1), intent(out) :: tmp_symbol
      character(len=10), intent(out) :: tmp_units


      ! Iterate over f_tritium and calculate f_deuterium
      f_deuterium = 1.0D0 - (f_tritium + f_helium3)
      tmp_cc = 1.0D0 - (f_deuterium + f_tritium + f_helium3)
      tmp_con = 1.0D0
      tmp_err = tmp_con * tmp_cc
      tmp_symbol = '='
      tmp_units = 'fraction'

   end subroutine constraint_eqn_092