anchor.diff:      write(*,"(' alpha       =',1p,E12.4)") params%alpha
       ! write(*,"(' X           =',1p,E12.4)") X
       write(*,*)'****************************************'
  -    read(*,*)
  +    !read(*,*)
   
     end subroutine display_parameters
   
  
positive.code:     real(kind = x_precision), parameter                    :: t_min = 5.0d-1
      real(kind = x_precision), parameter                    :: t_max = 4.49d0
  
      integer,                  parameter                    :: nb_it = 100
      real(kind = x_precision)                               :: eps   = 1.0d-4
      real(kind = x_precision)                               :: eps2   = 5.0d-1
  
  
negative.code: 
      call quadratic(coeff_a , coeff_b , coeff_c , H)
  
  
      rho                  = Sigma / H
      P_rad                = T**4
      P_gaz                = rho * T
  