| #! /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 True: | |
| # 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 | |
| sys.stdout.write(str(d)) | |
| # Flush so the output is seen immediately | |
| sys.stdout.flush() | |
| if __name__ == "__main__": | |
| main() |