
clear

xhi=4*pi ;
x = -xhi:0.05*pi:xhi ; 
tstep=0.05 ; 
nsteps=250 ; 
t=0:tstep:tstep*nsteps ; 

m=0;

sol=pdepe(m,@demo4fun,@demo4ic,@demo4bc,x,t);

u=sol(:,:,1) ;

for i=1:nsteps+1
    
  uu = u(i,:) ;

    subplot(2,1,1)
    plot(x,uu) 
    ylim([-1.0,1.0]) ; 
    mov(i) = getframe ; 
end

movie(mov, 1) 