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From: David Entwistle <qnivq.ragjvfgyr@ogvagrearg.pbz>
Newsgroups: rec.puzzles
Subject: Re: Repeated digits in Pi -- the Feynman point
Date: Thu, 3 Jul 2025 14:21:01 -0000 (UTC)
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On Thu, 03 Jul 2025 15:30:02 +0300, Phil Carmody wrote:

> By hand, I think I'd favour the spigot method. I know Matt Parker
> (/Stand-Up Maths/ on youtube) likes to organise the manual calculation
> of pi on "pi day", and I'm a little disappointed he's never tried
> spigot. I think its Big-Oh is superior to any of the algorithms that
> effectively do arbitrary precision arithmetic, as you never need to deal
> with numbers much bigger than a hundred.

Yes, I've just got to that in Chapter 6 of pi Unleashed. The book includes 
a faster variant that calculates 1000pi and includes C source code. It 
looks a little opaque, at first reading, but I'm sure I can get something 
to work. I'll give it a go shortly.

I've implemented a solution based on the Leibniz series and a variation of 
that which convergences somewhat faster.

Pi Unleashed is an interesting read. It starts of on a bit of a ramble, 
but includes lots of fascinating details. The array of formula to 
calculate pi is quite something.

-- 
David Entwistle