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From Phil Steitz <phil.ste...@gmail.com>
Subject Re: [math] AbstractStorelessStats stores raw data.
Date Fri, 02 Aug 2013 22:48:04 GMT
On 8/2/13 3:09 PM, Ajo Fod wrote:
> The class design of AbstractStorelessStats (Storeless) suggests that it is
> storing data in its parent AbstractUnivariate (Parent) and there are
> methods accesible to a child of this class that shouldn't be to something
> that is storeless in:
>
> private double[] storedData;
>
> ... perhaps Percentile etc should inherit from another subclass of the
> Parent?
>
I agree that there is no reason that
AbstractStorelessUnivariateStatistic should extend
AbstractUnivariateStatistic and the smelliness of exposing getData
in the child is a good reason for it *not* to.  I think the
implemented interfaces do make sense to inherit from one another,
but the abstract parents should be independent.  While cleaning this
up, I would also nuke the argumentless evaluate() from
AbstractUnivariateStatistic.

Percentile in its current implementation requires the data to be
stored in memory, so it is not a "storeless" - i.e., it should
inherit as it does from AbstractUnivariateStatistic.  We have been
talking about implementing a "storeless" approximation algorithm,
but that should go in a new class which would inherit from
AbstractStorelessUnivariateStatistic.

There may be other reasons that I don't remember for why the
abstract parent inheritence is there.  But those should be picked up
by the unit tests.  Any better ideas on how to achieve what we have
been achieving with these classes?  As I said above, as long as the
tests pass with only trivial mods, I am OK breaking the parent /
child on the abstract parents.  Now is a great time to think about
other ways to make the code easier to understand / use.

Phil

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