Hello.
Side note: Top-posting is quite annoying in these discussions...
Le dim. 2 juin 2019 à 21:27, Eric Barnhill <ericbarnh...@gmail.com> a écrit :
>
> As discussed on prior threads you should have both. There will need to be
> static convenience methods for a user who wants to make a very simple call,
> say Stats.mean() . But, as Alex said, this convenience class will just be a
> front end for the statistics functionality itself. That needs to be in its
> own classes (Mean(), Variance()) which can produce instances that give the
> user more flexibility, For example storeless statistics like Mean() or
> Variance(), or StandardDeviation(), should be updatable, as Gilles said, or
> handle different kind of streams like Alex said. Yet these classes need to
> be designed so that they perform as well as simple implementations when
> desired.
>
Related discussion:
https://issues.apache.org/jira/browse/STATISTICS-14
I agree with the requirement that "simple" usage must be possible.
However, it seems to me that the discussion is upside-down: simple
usage can always be provided by another layer (similar to the "toArray"
method in JDK's "List"). Seamless integration with stream does not
as obvious; hence should not be an afterthought.
Unless I'm mistaken, another way to look at it, is the "in-memoy" vs
"storeless" divide. The latter being the most interesting case (when the
quantity can be computed) design-wise.
I suggest that the testing ground (read: code) is to provide the variance.
And see how it plays with a "DoubleStream", how it can also provide
"sum of squares" and "mean"; or how, inversely, "sum of squares" and
"mean" can be "combined" to provide variance.
Regards,
Gilles
> On Sun, Jun 2, 2019 at 5:45 AM Virendra singh Rajpurohit <
> virendrasing...@gmail.com> wrote:
>
> > I've been trying to make summary statistics class. I have some doubt.
> > There is a class DoubleSummaryStatistics in java.util package(There are two
> > more for Int and Long). I'll attach this file here.
> > Do I have to design SummaryStatistics in this way only? I mean,
> > description on DoubleSummaryStatistics is "This class is designed to work
> > with (though does not require) streams
> > <https://docs.oracle.com/javase/8/docs/api/java/util/stream/package-summary.html>.
> > For example, you can compute summary statistics on a stream of doubles with:
> >
> >
> > DoubleSummaryStatistics stats =
> > doubleStream.collect(DoubleSummaryStatistics::new,
> >
> > DoubleSummaryStatistics::accept,
> >
> >
> > DoubleSummaryStatistics::combine);"
> > Earlier my understanding of the project was that the user just have to
> > call the function "getSummary()" & all the calculations will be done
> > automatically in streams. but As we can see in DoubleSummaryStatistics we
> > have to call collect() method.
> > There are some functions like max, min, sum, count, average which are
> > already defined in this class. So should I extend this class in my class or
> > not? Also, I'll have to add more statistics other than max,min,sum for that
> > I have to override accept() function which will be used for streams.
> >
> > Warm Regards,
> > --
> > *Virendra Singh Rajpurohit*
> >
> > *University of Petroleum and Energy Studies,Dehradun*
> > Linkedin:https://www.linkedin.com/in/virendra-singh-rajpurohit
> >
> >
> >
> >
> >
> > [image: Mailtrack]
> > <https://mailtrack.io?utm_source=gmail&utm_medium=signature&utm_campaign=signaturevirality5&;>
> > Sender
> > notified by
> > Mailtrack
> > <https://mailtrack.io?utm_source=gmail&utm_medium=signature&utm_campaign=signaturevirality5&;>
> > 06/02/19,
> > 6:14:27 PM
> >
> > ---------------------------------------------------------------------
> > To unsubscribe, e-mail: dev-unsubscr...@commons.apache.org
> > For additional commands, e-mail: dev-h...@commons.apache.org
---------------------------------------------------------------------
To unsubscribe, e-mail: dev-unsubscr...@commons.apache.org
For additional commands, e-mail: dev-h...@commons.apache.org
