[armedbear-devel] Fixing PRINT.RANDOM-STATE.1

[Jorge Tavares]

Hi,

On Sat, Jul 16, 2011 at 11:09, Erik Huelsmann <ehuels at gmail.com> wrote:

> It looks - also given Mark's reaction - like we may need to implement this
> in Lisp to achieve the behaviour we need: readable random states. Possibly,
> we can also offer a (non-printable) wrapper around the java Random object...
> Thanks for your feedback! I'll save the link to see if that solution or the
> algorithms in SBCL can help us out here.

The algorithm implemented in SBCL is the Mersenne Twister
(http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html) and it is a
fast and very good random number generator. The implementation in SBCL
is a good one and provides readable random states. I believe having a
similar implementation in ABCL would be very nice since the generator
that comes with Java is a low-quality one (it's a Linear Congruential
Generator). SBCL also provides a specific feature to set a seed with a
number: sb-ext:seed-random-state. It's a useful addition.

As a side note, not long ago I've used the MT in SBCL as a starting
point for a small portable library of random number generators.
Unfortunately I still was not able to put it in a decent state for
release...


Best,
Jorge

-- 
http://jorgetavares.com