anchor.diff:      call quadratic(coeff_a , coeff_b , coeff_c , H)
   
   
  -    
  +
       rho                  = Sigma / H
       P_rad                = T**4
       P_gaz                = rho * T
  
positive.code:     ! eps -> Precision
      ! T-> Fixed variable
      !-------------------------------------------------------------------------
      dichotomy             = (Smin+Smax)/2.
      j = 0
      call variables(T, Smin, Omega, H, rho, cs, nu, Q_plus, Q_minus, K_ff, K_e,&
           tau_eff, P_rad, P_gaz,E_ff,Fz,f_min,Sigma_0, Omega_0,rs,T_0,rho_0)
      
      call variables(T, Smax, Omega, H, rho, cs, nu, Q_plus, Q_minus, K_ff, K_e, &
           tau_eff, P_rad, P_gaz,E_ff,Fz,f_max,Sigma_0, Omega_0,rs,T_0, rho_0)
      
      write(*,*)'fmin = ',f_min
      write(*,*)'fmax = ',f_max
      
      if ( f_max * f_min .gt. 0.) then
         write(*,*)'This function image does not switch its sign in this particular interval.'
      endif
  
negative.code:     real(kind=x_precision),intent(out)                      :: Omega_0
      real(kind=x_precision),intent(out)                      :: T_0
      real(kind=x_precision),intent(out)                      :: rho_0
      real(kind=x_precision)                                  :: nu_0
  
      type(parameters)                                        :: param
      !------------------------------------------------------------------------
  