On Tue, Apr 09, 2013 at 08:26:31PM +0200, Jos Koot wrote: > Would it be possible to use > <http://en.wikipedia.org/wiki/Stirling%27s_approximation> Stirling's > approximation for a fast inexact first approximation for factorials of very > big numbers and from there quickly get to an exact factorial? (if exactness > is required) I don't know for I haven't thought thoroughly about this. > Jos.
I don't know of a way take an approximation and by applying some operation to it to get a better one. There are ways to do thie for other functions, like squate root, but I don't know one for factorial. But there might be a bound on the error in Stirling's approximation that you cna use teo determine whether that's good enough for your application (if you have one). -- hendrik ____________________ Racket Users list: http://lists.racket-lang.org/users
