summaryrefslogtreecommitdiffstats
path: root/Demo/scripts/mpzpi.py
blob: 03b90fba30bf9569b9181a85e30fcbdbb05b3ef2 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
#! /usr/bin/env python
# Print digits of pi forever.
#
# The algorithm, using Python's 'long' integers ("bignums"), works
# with continued fractions, and was conceived by Lambert Meertens.
#
# See also the ABC Programmer's Handbook, by Geurts, Meertens & Pemberton,
# published by Prentice-Hall (UK) Ltd., 1990.

import sys

def main():
        k, a, b, a1, b1 = 2, 4, 1, 12, 4
        while 1:
                # Next approximation
                p, q, k = k*k, 2*k+1, k+1
                a, b, a1, b1 = a1, b1, p*a+q*a1, p*b+q*b1
                # Print common digits
                d, d1 = a/b, a1/b1
                while d == d1:
                        output(d)
                        a, a1 = 10*(a%b), 10*(a1%b1)
                        d, d1 = a/b, a1/b1

def output(d):
        # Use write() to avoid spaces between the digits
        # Use int(d) to avoid a trailing L after each digit
        sys.stdout.write(`int(d)`)
        # Flush so the output is seen immediately
        sys.stdout.flush()

main()