title: Fast algorithms for computing the factorial
body: <p>I found <a href="http://www.luschny.de/math/factorial/FastFactorialFunctions.htm" rel="noreferrer">this page</a> describing a number of algorithms for computing the factorial. Unfortunately, the explanations are terse and I don't feel like sifting through line after line of source code to understand the basic principles behind the algorithms.</p>
  
  <p>Can anybody point me to more detailed descriptions of these (or other fast) algorithms for computing the factorial?</p>
  
  <p><strong>Edit:</strong> <a href="http://en.literateprograms.org/Factorials_with_prime_factorization_&#40;Python&#41;" rel="noreferrer">This page</a> describes the method of prime factorization, the technique common to all of the best-performing factorial algorithms. It also contains some nice example code in Python. The author links to <a href="http://numbers.computation.free.fr/Constants/Algorithms/splitting.html" rel="noreferrer">a description of binary splitting</a> and references an article in the <em>Journal of Algorithms</em> ("On the Complexity of Calculating Factorials") that looks promising, if I could only get my hands on it.</p>