mahout-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Sean Owen <sro...@gmail.com>
Subject Re: randomseedgenerator
Date Wed, 01 Jul 2009 20:03:32 GMT
Sorry I meant Mahout's class by this name. Just provides a factory
method which will provide a seeded or non-seeded java.util.Random
depending on whether it's being run in the context of tests or not.

I imagine all PRNGs need to be injected for us to confidently run
tests deterministically?

Nothing in my part of the code particularly cares about the PRNG being
hard-core random. Random is good for me.

Why does some of the code need the Mersenne twister PRNG... or does
it? I prefer keeping it standard, then simple, if possible. Any PRNG
is cool by me, just want to pick one solution unless there is a
compelling reason not to. Fine with one solution now, and a different
one solution later.

On Wed, Jul 1, 2009 at 8:57 PM, Ted Dunning<ted.dunning@gmail.com> wrote:
> RandomUtils is in commons.lang.math which is a separate class/package/world
> entirely.  It seems to provide almost no added value over Random.  In
> particular, I don't see why this helps make random numbers more
> deterministic than any competent PRNG implementation.  All implementations
> that I know of allow seeding.  The javadoc on RandomUtils does not inspire
> confidence in me since it implies that it inherits the well-known defects of
> java.math.Random.
>
> The key here is just to allow (but not require) the RNG to be injectable for
> any class that needs to generate random numbers.
>
> What value does RandomUtils bring over temporary use of java.math.Random and
> long term use of commons math RandomData?

Mime
View raw message