Chudnovsky.py

import math
def sqrt(n, one):

    floating_point_precision = 10**16
    n_float = float((n * floating_point_precision) // one) / floating_point_precision
    x = (int(floating_point_precision * math.sqrt(n_float)) * one) // floating_point_precision
    n_one = n * one
    while 1:
        x_old = x
        x = (x + n_one // x) // 2
        if x == x_old:
            break
    return x

def pi_chudnovsky_bs(digits):

    C = 640320
    C3_OVER_24 = C**3 // 24
    def bs(a, b):
        if b - a == 1:
            if a == 0:
                Pab = Qab = 1
            else:
                Pab = (6*a-5)*(2*a-1)*(6*a-1)
                Qab = a*a*a*C3_OVER_24
            Tab = Pab * (13591409 + 545140134*a)
            if a & 1:
                Tab = -Tab
        else:

            m = (a + b) // 2
            Pam, Qam, Tam = bs(a, m)
            Pmb, Qmb, Tmb = bs(m, b)
            Pab = Pam * Pmb
            Qab = Qam * Qmb
            Tab = Qmb * Tam + Pam * Tmb
        return Pab, Qab, Tab
    DIGITS_PER_TERM = math.log10(C3_OVER_24/6/2/6)
    N = int(digits/DIGITS_PER_TERM + 1)
    P, Q, T = bs(0, N)
    one = 10**digits
    sqrtC = sqrt(10005*one, one)
    return (Q*426880*sqrtC) // T

if __name__ == "__main__":
    res = pi_chudnovsky_bs(int(input("Enter the number of digits")))
    print(res)