[
https://issues.apache.org/jira/browse/MATH-701?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13143706#comment-13143706
]
Phil Steitz commented on MATH-701:
----------------------------------
+1 to changing the default in the RandomDataImpl to a Well generator
(documenting this)
+1 as well to trying to find a better default seed (documenting how it works).
Harmony still belongs to us, so we can certainly look at / imitate the impl
there.
The reason that the argumentless constructor exists is to allow users to accept
the default generator. The lazy initialization idiom was chosen because in some
cases, users may choose to invoke the setter instead of passing a generator as
a constructor argument. This is an older style no longer in use much in
[math]. I would be OK getting rid of this - i.e., having the argumentless
constructor take the hit to create a default instance.
-0 for separating out the secure stuff. RandomDataImpl is an aggregate class
that bundles a lot of commonly used random data generation methods. Just as
the random generator is pluggable, so is the secure random generator, which
makes the class convenient to use for applications that require both kinds of
random values. I think its simpler and more convenient to bundle things as
they are. Of course, I have been using this class for a long time, so I may
not be the best judge of what is simplest / easiest to use.
> Seeding a default RNG
> ---------------------
>
> Key: MATH-701
> URL: https://issues.apache.org/jira/browse/MATH-701
> Project: Commons Math
> Issue Type: Bug
> Reporter: Gilles
> Assignee: Gilles
> Fix For: 3.0
>
>
> In "RandomDataImpl":
> {code}
> private RandomGenerator getRan() {
> if (rand == null) {
> rand = new JDKRandomGenerator();
> rand.setSeed(System.currentTimeMillis());
> }
> return rand;
> }
> {code}
> The conditional branch is used by "sample()" in
> "AbstractContinuousDistribution".
> When several "...Distribution" objects are instantiated in a short time
> interval, they are seeded with the same value.
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators:
https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa
For more information on JIRA, see: http://www.atlassian.com/software/jira
