[Nickle] Fwd: nickle slow for large factorials

[Keith Packard]

On Sun, 4 Jul 2010 11:32:46 +0200, Michel Alexandre Salim <michael.silvanus at gmail.com> wrote:

> It looks like Nickle's handling of bignums is inefficient -- has there
> been thoughts about using GMP for large numbers? The tail recursion
> itself is fine, even for mutually recursive functions:

I've implemented a more efficient factorial function as described by
Peter Luschny as described here:

http://www.luschny.de/math/factorial/FastFactorialFunctions.htm

This still isn't amazingly fast for large factorials (666666 takes a bit
more than a minute), but is a whole lot faster than the naïve algorithm
originally included in nickle, and should be faster than the GMP
factorial algorithm for large values, although I haven't compared it
myself.

This code is on the master branch in the nickle repository; please feel
free to give it a try.

-- 
keith.packard at intel.com
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