elliptic_integral_approximation.py

import numpy as np

def schlawin(x):
    a1 = 0.44325141463
    a2 = 0.06260601220
    a3 = 0.04757383546
    a4 = 0.01736506451
    b1 = 0.24998368310
    b2 = 0.09200180037
    b3 = 0.04069697526
    b4 = 0.00526449639
    return 1 + x*(a1 + x*(a2 + x*(a3 + x*a4))) + x*(b1 + x*(b2 + x*(b3 + x*b4)))*np.log(1/x)