function heat1
disp('Initial Value Problem of Parabolic PDE')
disp('Model Equation u_t = eps u_xx ')
disp('Initial condition u(x,0) = H(x), x in [-1,1] ')
eps = input('Diffusion coefficient eps ?  (default = 0.02)  ');
if isempty(eps)
   eps= 0.02;
   end

time = input('Stopping time ?  (default = 1)  ');
if isempty(time)
   time = 1.;
   end

x=-1.:0.01:1.;
dt = time/20;
t = 0:dt:time;
clf;
for i=1:length(t)
     u = erf(x/sqrt(4.*eps*t(i)));
     plot(x,u)
     title(['Solution at time t = ',num2str(t(i))]);
     M(i) = getframe;
%    fname = ['tmp',num2str(i)];
%    print('-djpeg',fname)
end
movie(M,3)
