Time for another update. Isaac Gouy provided a Java implementation based on mine (ie still pre computes the tables in Perl) that brought the times down to sub 9 seconds. real 0m8.966s user 0m5.815s sys 0m1.488s But the big news is that William James' revision of his previous Ocaml version is now the fastest. real 0m3.660s user 0m1.958s sys 0m1.421s The source code for both are available on the web site for you to examine.