import numpy as np
import scipy.interpolate as itp
import matplotlib.pyplot as plt
x = np.linspace(0., 5., 15)
y = np.sinc(x)
f3 = itp.interp1d(x, y, kind='cubic')
xdense = np.linspace(0.,5., 100)
yapprox = f3(xdense)
yexact = np.sinc(xdense)
plt.plot(x, y, 'o', xdense, yexact, '-', xdense, yapprox, '--')
plt.legend(['data', 'exact', 'interpolate'], loc='best')
plt.show()