commons-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From cwinter <chwinterho...@aol.com>
Subject Re: [math] Distributions over sample spaces other than R
Date Sat, 05 Nov 2011 19:11:33 GMT
Hi,

I'm picking up the discussion on the interface structure for distributions
again.

Now there is consensus on having separate roots for each domain: one for
real-valued distributions and one for integer distributions.

After thinking once more about distributions with densities vs. those
without, I agree that two interfaces for the real domain are not necessary,
and we should go for simplicity. For distributions not having a density, the
implementation of density(double) could provide results being as meaningful
as possible. It could return infinity (where the distribution has "discrete
points" - as proposed by S├ębastien on another thread
http://apache-commons.680414.n4.nabble.com/math-Continuous-Distribution-tp3950057p3950057.html)
or something else seeming to be appropriate (where there is another reason
for the actual density not to exist).

The naming issue is still open. In my opion, a name containing the name of
the distribution's domain (instead of a property) helps to avoid ambiguity
and funny curiosities (A random sample of a normal distribution is
associated with a *discrete* empirical distribution which approximately
renders the according normal distribution. However, the sample's
distribution would implement the interface for the real domain. Thus the
interface for the integer domain should not have the name
DiscreteDistribution.). Additionally, it would be easier to provide more
roots if users require support for further domains (e.g. if a multidimension
normal distribution shall be implemented).

Christian

--
View this message in context: http://apache-commons.680414.n4.nabble.com/math-Distributions-over-sample-spaces-other-than-R-tp3931349p3994066.html
Sent from the Commons - Dev mailing list archive at Nabble.com.

---------------------------------------------------------------------
To unsubscribe, e-mail: dev-unsubscribe@commons.apache.org
For additional commands, e-mail: dev-help@commons.apache.org


Mime
View raw message