From: "Michał C" <ciebiada@gmail.com>
To: caml-list@yquem.inria.fr
Subject: Random number generator
Date: Tue, 30 Sep 2008 15:17:05 +0200 [thread overview]
Message-ID: <E1377AE6-AA53-434D-B293-CDF4529651C2@gmail.com> (raw)
Hello!
Do You maybe have any idea how good is the standard RNG from random.ml
module? I know that it's quite fast but what about the quality of
generated numbers?
I've tried implementing various random number generators for the whole
yesterday but I couldn't bypass ocaml's int limitations. Almost
everything bases on unsigned integers (0..2^32-1) so despiting the
fact my range is half of that (using Int32) I'm having troubles when
integer overflows...
I would like to implement combined MWC (multiple with carry) algorithm
based on 2 x 16bit mwc's. I'ts very easy (at last in c/c++ where i can
use unsigned ints), fast and according to what I've read it's
generating very nice random numbers.
It goes like this:
z = w= some seeds (big numbers)
z = 36969 * (z & 65535) + (z >> 16)
w = 18000 * (w & 65535) + (w >> 16)
return ( (z << 16) + (w & 65535) ) // combining two 16 bit numbers to
one 32 bit
but i cant think of anything by myself, i mean i could use some "abs"
or something but i doubt it wouldn't ruin the whole algorithm.
P.S.
some time ago I promised that I will keep you informed how my ray-
tracer will do, here it is:
http://neos1.blogspot.com
next reply other threads:[~2008-09-30 13:17 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-09-30 13:17 Michał C [this message]
2008-09-30 13:36 ` [Caml-list] " Till Varoquaux
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=E1377AE6-AA53-434D-B293-CDF4529651C2@gmail.com \
--to=ciebiada@gmail.com \
--cc=caml-list@yquem.inria.fr \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox