Initial revision

Demo/scripts/pi.py

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+#! /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()