[no subject]

[Bart Vandewoestyne]

Hello list,

For an assignment, my students are using finite differences to compute a 
solution of the 1D wave equation.  Because I only want them to bother with the 
numerics, not with practical plotting stuff, I've made available the following 
script which they can use to animate their solution:

--------------------------- begin script ---------------------------

function generate_movie1d(f, g, Nx, t_max, L, c, lambda)

[u dt] = wave1d(f, g, Nx, t_max, L, c, lambda);

mymax = max(max(u));
mymin = min(min(u));

x = linspace(0, L, Nx+1);
for i=1:size(u,2)

  plot(x, u(:,i), '*r')
  axis([0 L mymin mymax])
  title(sprintf('Solution of the one-dimensional wave equation at t = %f', 
(i-1)*dt))
  drawnow
  hold off

end

------------------------------ end script ----------------------------------

This all worked fine on my (fast) Ubuntu desktop PC, but one of my students 
(working on a quite fast Windows Vista laptop) reported 'flickering' 
graphics... the updating of the animation is very bad and makes the animation 
very unfluent.  I assume this is not due to a slow computer (his laptop is 
quite fast), but rather due to the fact that I use the drawnow command to 
update the graphics...  maybe also due to the fact that he works on Windows 
Vista?  Unfortunately, I don't know how I would have to change my code so that 
the updating is more 'fluent'.

Can anybody help me out here, so that I can give my students a script that also 
gives fluent animations, even on Windows?  What is the general technique to do 
this?  Am i doing it the right way?

Kind regards,
Bart