Higher approximation error than interpolation error for Runge's function

[vchizhov]

I tried the code with the Runge function and I am getting a larger approximation error than interpolation error, which to me suggests that either something is wrong with the algorithm, or maybe I haven't set up things correctly. Here is how my setup looks like:

fx = "(1.0+25.0 * x**2)**-1"
fx_der = "-50.0*x * (1.0+25.0 * x**2)**-2"
fxn = "runge"
interval = [-1.0, 1.0]
n = 5
px, xn, history = remez(fx, fx_der, interval, n)
visualization(fx, px, xn, history, interval, n, fxn)

I have modified the function visualization to accept a fxn parameter which is the name of the function, in order to avoid issues with savefig. I haven't modified anything else.