function val=test_interp_conv(L,n)
% n = number of intervals     

% the "t" points
x=-L:2*L/n:L;

% the assigned values
y=runge(x); 

% "all" points
xi=-L:0.001:L;

% the values of the interpolant at xi: yi=P_n(xi)
yi=myinterp(x,y,xi);

% the max norm between yi and f(xi)
val = max(abs(yi-runge(xi)));
