Hello Fabien,
> On 5 Aug 2017, at 12:15, Fabien COELHO <coe...@cri.ensmp.fr> wrote: > > > Hello Alik, > > I've done some math investigations, which consisted in spending one hour with > Christian, a statistician colleague of mine. He took an old book out of a > shelf, opened it to page 550 (roughly in the middle), and explained to me how > to build a real zipfian distribution random generator. > > The iterative method is for parameter a>1 and works for unbounded values. It > is simple to add a bound. In practice the iterative method is quite > effective, i.e. number of iterations is typically small, at least if the > bound is large and if parameter a is not too close to 1. > I've attached a python3 script which implements the algorithm. It looks like > magic. Beware that a C implementation should take care of float and int > overflows. > Thank you for the script. I will rewrite it to C and add to the patch soon. — Thanks and Regards, Alik Khilazhev Postgres Professional: http://www.postgrespro.com The Russian Postgres Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
