Python program to calculate digits of 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}}`

#made by Raxit Gupta

import decimal 

import math 

#we use Chundnovsky's formulae

def compute_pi(n):

  decimal.getcontext().prec = n + 3

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

  K = decimal.Decimal(6)

  M = decimal.Decimal(1)

  X = decimal.Decimal(1)

  L = decimal.Decimal(13591409)

  S = L

  # For better precision, we calculate to n+3 and remove the last two digit

  for i in range(1, n+3):

    M = decimal.Decimal(M* ((1728*i*i*i)-(2592*i*i)+(1104*i)-120)/(i*i*i))

    L = decimal.Decimal(545140134+L)

    X = decimal.Decimal(-262537412640768000*X)

    S += decimal.Decimal((M*L) / X)

    return str(C/S)[:-2]

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

P=compute_pi(n)

print(P)

         

if there is any mistake, please comment!