Factorial improvements

[Marsac Laurent]

Hello,

I'm currently trying to improve n! calculation (mpz/fac_ui.c) and i just
want to know if anyone else is already working on it, or who is
responsible of that file ?

As described in the TODO list, i'm doing the prime factorization of n!,
and shiftings for factors of 2. The first results seems to show my
algorithm improves performances and i hope i could send more details
here ASAP.

--
Laurent Marsac