%
% compute and plot the error between successive FE approximations
% by stepping through powers of 1/10
%

[t,x] = mycub_fe(0.1,20,[1 1]);

for j=1:4,

    dt(j) = 1/10^(j+1);

    [newt,newx] = mycub_fe(dt(j),20,[1 1]);

    xdiff = abs( newx(1:10:end,:) - x );

    err(j) = max( max( xdiff ) );

    x = newx;

end

loglog(10*dt,err,'x-')
xlabel('coarse dt','fontsize',16)
ylabel('max difference in FE solutions','fontsize',16)