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From: Ted Dunning <ted.dunning@gmail.com>
Date: Sun, 26 Sep 2010 21:10:31 -0700
Message-ID: <AANLkTinTgha=yo8Xj6p-VmjA5iHP7M2HmH-Y18WrrPtW@mail.gmail.com>
Subject: Re: [math] autocorr
To: Commons Users List <user@commons.apache.org>
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Everything in Colt was untested and as a result there were bugs and
inconsistencies.

As part of the Mahout project, we have redefined the matrix primitives to be
more amenable to our needs and simpler to extend than the original Colt
arrays.  We have been busily either testing and converting code that we
needed to build a scalable machine learning code and are simultaneously
deleting pretty much everything that doesn't contribute to that goal.

Some things are still around and some have already been deleted.  I believe
that I was the one who recently deleted the Descriptive statistics back
based largely on the fact that it wasn't very compatible with the rest of
Colt (it uses DoubleArrayList instead of DoubleArray1D, for instance) and
because most of the functions are relatively trivial.

Since autocorrelation depends on FFT's to compute and because it would be
quite a bit of work to implement good tests FFT's, I
think that is still the right decision for us to have made.

If you have a need for autocorrelation and would like to work with us to
rehabilitate and port the associated Colt code, I would
be happy to help by advising about our nascent conventions about how we are
organizing our code and what sort of testing and
porting is needed.


On Sun, Sep 26, 2010 at 8:36 PM, video axescon <video@axescon.com> wrote:

> Hello
>
> I cant find autocorrelation function in stats package. Is there a reason
> why
> it wasn't implemented?
> It exists in Colt project.
>
> cheers
>

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