Python program to calculate `\pi`

 Python program to calculate π

Chundnovsky's formulae:

`\frac{426880\sqrt{10005}}{\pi}=`

`\sum _{k=0}^{\infty}\frac{(6k)!(13591409+545140134k)}{(3k)!(k!)^3(-640320)^{3k}}`

import decimal 

import math 

#we use Chundnovsky's formulae

def compute_pi(n): 

     decimal.getcontext().prec=n+1

     A=426880*decimal.Decimal(10005).sqrt()

     B=6

     C=1

     D=1

     E=13591409

     F=E

     for i in range(1,n):

          C=C*((1728*i*i*i)-(2592*i*i)+(1104*i)-120)/(i*i*i)

          E+=545140134

          D*=0-262537412640768000

          F+=decimal.Decimal(C*E)/D

     pi=A/F

     return pi

n=int(input("Enter decimal places:"))

P=compute_pi(n)

print(P)

         

if there is any mistake, please comment!