anchor.diff:  
       do i = 2, pasx+1
           do j = 1, pasy
  -            write(1,*) 'a(', (save-1)*pasx+i-1, ',', j, ')=', eta(i,j), ';'
  +            write(1,*) 'a(', (nsave-1)*pasx+i-1, ',', j, ')=', eta(i,j), ';'
           end do
       end do
   
       ! Boucle principale (progression dans le temps)
   
       do n = 1, Nmax
  -        write(*,*) 'Pas de temps n :', n
  +        print *, 'Pas de temps n :', n
   
           ! Calcul de Beta et du laplacien
   
  
positive.code:                         - deta(i,2)/dt) - Ro*temp1*temp2 + Ro*temp3*             &
                          (-4*eta(i,j-1) + eta(i,j-2))/(2*dy) ) / temp4
                  temp5 = eta(i,j) + w*(temp5-eta(i,j))
                  if (abs(eta(i,j)).GT.0) then
                      erreur = abs( (temp5-eta(i,j)) / eta(i,j) )
                      if (erreur.GT.tol) then
                          fin = 0
                      endif
                  endif
                  aeta2 = eta(i,j)
  
negative.code: 
                  ! Red Black
  
                  do i = 2, pasx
                      do j = start+1, pasy-1, 2
                          temp1 = -2/dx**2 - 2/dy**2 - 1/Bu
                          temp1 = (q(i,j)/Bu - (eta(i+1,j)+eta(i-1,j))/dx**2   &
                                             - (eta(i,j+1)+eta(i,j-1))/dy**2  ) / temp1
                          temp1 = eta(i,j) + w*(temp1-eta(i,j))
                          if(abs(eta(i,j)) > 0.0D0) then
                              erreur = abs( (temp1-eta(i,j))/eta(i,j) )
                              if(erreur > tol) then
                                  fin = .false.
                              endif
                          endif
                          eta(i,j) = temp1 
                      end do
  
                      if(start == 2) then
                          start = 1
                      else 
                          start = 2
  