Pi Calculator

Calculate Pi with Python

Pi is an irrational number having non-recurring decimal values. We commonly know Pi=3.14 or Pi=22/7, but it is just an approximation for our ease. There are two methods to calculate the value of pi in python:

The formula is –

• X = 4 - 4/3 + 4/5 - 4/7 + 4/9 - ....

This series is never-ending, the more the terms this series contains, the closer the value of X converges to Pi value.

from math import factorial
from decimal import Decimal, getcontext
# Chudnovsky algorithm for figuring out pi
getcontext().prec=1000

pi_input = input('How many digits of pi would you like?')
n = int(pi_input)

def cal(n):
    t= Decimal(0)
    pi = Decimal(0)
    deno= Decimal(0)

    for k in range(n):
        t = ((-1)**k)*(factorial(6*k))*(13591409+545140134*k)
        deno = factorial(3*k)*(factorial(k)**3)*(640320**(3*k))
        pi += Decimal(t)/Decimal(deno)
    pi = pi * Decimal(12) / Decimal(640320 ** Decimal(1.5))
    pi = 1/pi
    return round(pi,n)

print(cal(n))

Built With

• markdown
• python