| #! /usr/local/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 = 2L, 4L, 1L, 12L, 4L |
| while 1: |
| # Next approximation |
| p, q, k = k*k, 2L*k+1L, k+1L |
| 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 = 10L*(a%b), 10L*(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() |