http://en.wikipedia.org/wiki/Factorial#Computation

You can not get as fast as C, unless you write a C extension.

For practical purposes and non-gigantic numbers, I would just
precompute all values we care about and store them in an array.

-- Matma Rex



2012/2/17 Junayeed Ahnaf Nirjhor <zombiegenerator / aol.com>:
> Hello,
>
> What is the most efficient way in Ruby to calculate the factorial of any
> given sum? Is there any way to make it as fast as in C?
>
> Complexity doesn't matter as long as it works correctly.
> --
> Junayeed Ahnaf Nirjhor
> Core Developer Intern, Diaspora
> Twitter - Nirjhor <http://twitter.com/nirjhor>