#!/usr/bin/python3
# Gauss-Legendre quadrature

def int_gauss(f, nodes, weights):
  result = 0.0
  for x, w in zip(nodes, weights):
    result += w * f(x)
  return result

# compute nodes and weights on [-1, 1] with gaussxw.gaussxw():
from gaussxw import gaussxw
N = 100
x, w = gaussxw(N)
    
# adapt x -> x' et w -> w' to integration domain [a, b]:
a, b = 0, 1
xp = 0.5*(b - a)*x + 0.5*(b + a) 
wp = 0.5*(b - a)*w 

# integrate some function over [a, b]:
from math import atanh
print("Résultat:", int_gauss(atanh, xp, wp))