cpython/Demo/scripts/pi.py

31 lines
779 B
Python
Executable File

#! /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
#print a, b, a1, b1
while d = d1:
# Use write() to avoid spaces between the digits
sys.stdout.write(`int(d)`)
# Flush so the output is seen immediately
sys.stdout.flush()
a, a1 = 10l*(a%b), 10l*(a1%b1)
d, d1 = a/b, a1/b1
main()