anchor.diff:      implicit none
       integer::i = 0
       real(kind = x_precision)                               :: temp = 0.0d0
  -    real(kind = x_precision), parameter                    :: t_min = 1.0d-3
  -    real(kind = x_precision), parameter                    :: t_max = 1.0d0
  +    real(kind = x_precision), parameter                    :: t_min = 1.0d-6
  +    real(kind = x_precision), parameter                    :: t_max = 2.0d-6
       integer,                  parameter                    :: nb_it = 10
       real(kind = x_precision)                               :: sigma = 0.0d0
  -    real(kind = x_precision)                               :: Smin = 1.0d-3
  -    real(kind = x_precision)                               :: Smax = 1.0d0
  -    real(kind = x_precision)                               :: eps = 1.0d-5
  +    real(kind = x_precision)                               :: Smin = 0.0d-5
  +    real(kind = x_precision)                               :: Smax = 0.0d-2
  +    real(kind = x_precision)                               :: eps = 1.0d-4
       real(kind = x_precision)                               :: omega = 0.0d0
  -    real(kind = x_precision)                               :: r = 0.0d0
  +    real(kind = x_precision)                               :: r = 5.0d0
       type(parameters)                                       :: param
       !----------------------------------------------------------------------
       
  
positive.code:     open(18,file = 'Temperature_Sigma.dat',status='unknown',action='readwrite') 
      write(18,*)"T Sigma"
      do i           = 1 , nb_it
         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
  
negative.code:   ! T-> Fixed variable
    !-------------------------------------------------------------------------
    dichotomy             = (Smin+Smax)/2.
    write(*,*)f(T,Smin,omega)
    write(*,*)f(T,Smax,omega)
    write(*,*)T,Smin,Smax,j
    j = 0
    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)
          if( f(T,Smin,omega) * f(T,dichotomy,omega) .lt. 0.) then
             Smax         = dichotomy
             write(*,*)'smin=',smin,' smax=', smax
  