anchor.diff:      open(18,file = 'Temperature_Sigma.dat',status='unknown',action='readwrite') 
       write(18,*)"T Sigma"
       do i           = 1 , nb_it
  +       Smin=5.0d-4
  +       Smax=1.0d-3
          temp        = (t_max-t_min)/(nb_it-1)*(i-1) + t_min
          sigma       = dichotomy(Smin, Smax, eps, temp, omega)
  -       Smin=1.0e-3
  -       Smax=1.0d0
  +
          
          write(18,*)temp," ",sigma
       enddo
  
positive.code:   ! T-> Fixed variable
    !-------------------------------------------------------------------------
    dichotomy             = (Smin+Smax)/2.
  
    if ( f(T,Smin,omega) * f(T,Smax,omega) .gt. 0.) then
       write(*,*)'This function image does not switch its sign in this particular interval.'
    endif
    if( f(T,Smin,omega) * f(T,Smax,omega) .lt. 0.) then
       !iteration:do while ( dabs( f(T,dichotomy,omega) ) .ge. eps .and. j .lt. N)
       iteration:do while ( dabs( Smax - Smin ) .ge. eps .and. j .lt. N)
          if( f(T,Smin,omega) * f(T,dichotomy,omega) .lt. 0.) then
             Smax         = dichotomy
             write(*,*)'smin=',smin,' smax=', smax
  
negative.code:   Q_minus             = 2._x_precision * Fz /Sigma
    Q_plus              = 9._x_precision /4._x_precision * nu * Omega**2
    f                   = Q_plus - Q_minus
  !  write(*,*)'Q_plus = ', Q_plus
  !  write(*,*)'Q_minus = ', Q_minus
  
    end function f
  
  