anchor.diff:  
           do i = 2, pasx
               do j = 2, pasy-1
  -                temp1 = (eta(i-1,j)+eta(i+1,j)-2*eta(i,j))/(dx*dx)        &
  -                      + (eta(i,j-1)+eta(i,j+1)-2*eta(i,j))/(dy*dy)
  -                temp2 = ((eta(i+1,j)-eta(i-1,j))/(2*dx))**2               &
  -                      + ((eta(i,j+1)-eta(i,j-1))/(2*dy))**2
  +                temp1 = (eta(i-1,j) + eta(i+1,j) - 2*eta(i,j))/(dx*dx)        &
  +                      + (eta(i,j-1) + eta(i,j+1) - 2*eta(i,j))/(dy*dy)
  +                temp2 = ((eta(i+1,j) - eta(i-1,j))/(2*dx))**2               &
  +                      + ((eta(i,j+1) - eta(i,j-1))/(2*dy))**2
                   b(i,j) = (Bu+Ro*eta(i,j))*temp1 + Ro/2*temp2
                   q(i,j) = temp1
               end do
  
positive.code:                     temp5 = (eta(i,j+2) + eta(i,j) - 2*eta(i,j+1))/(dy*dy)
                      v2(i,j) = temp2-Et*(temp1 - temp3)/dt             &
                               - Ro*(temp2*temp5 - temp1*temp4)
                      j = pasy
             
                      ! u (j=pasy)            
  
                      temp1 = (-4*eta(i,j-1) + eta(i,j-2) + 3*eta(i,j))/2/dy
                      temp2 = (eta(i+1,j) - eta(i-1,j))/2/dx
  
negative.code: 
          end do  
         
          print *, '    no it. =', compt
          kmoy = kmoy + compt
  
          ! Copie de eta (futur calcul des vitesses)
  
          if(n == nsave*fsave-1) then
              do i = 1, pasx+1
                  do j = 1, pasy
                      leta(i,j) = eta(i,j)
                  end do
  