#!/usr/bin/env python

from gaussxw import gaussxw

def f(x):
    return x**4 - 2*x + 1

N = 3
a = 0.0
b = 2.0

# Calculate the sample points and weights, then map them
# to the required integration domain
x,w = gaussxw(N)
xp = 0.5*(b-a)*x + 0.5*(b+a)
wp = 0.5*(b-a)*w

# Perform the integration
s = 0.0
for k in range(N):
    s += wp[k]*f(xp[k])

print(s)