[AstroPy] Missing some statistical method for your astronomy analyses in Python?
Tue Jan 15 04:29:58 CST 2013
I think this is something that should be brought up with the Numpy
developers, and it would probably benefit everyone to have a faster
median calculation function (not just astronomers). At the moment,
Numpy just uses a quicksort, but if one could achieve speedups of 5x,
then I think the Numpy devs might be interested.
On 15 January 2013 10:51, Jerome Caron <firstname.lastname@example.org> wrote:
> Dear Christoph
> I think the calculation of median values in Numpy is not optimal. I don't
> know if there are other libraries that do better?
> On my machine I get these results:
>>>> data = numpy.random.rand(5000,5000)
>>>> t0=time.time();print numpy.ma.median(data);print time.time()-t0
>>>> t0=time.time();print numpy.median(data);print time.time()-t0
>>>> t0=time.time();print aspylib.astro.get_median(data);print time.time()-t0
> [ 0.49984574]
> The median calculation in Aspylib is using C code from Nicolas Devillard
> (can be found here: http://ndevilla.free.fr/median/index.html) interfaced
> with ctypes.
> It could be easily re-used for other, more official packages. I think the
> code also finds quantiles efficiently.
> Kind regards
> Jerome Caron
> De : Christoph Deil <email@example.com>
> À : "firstname.lastname@example.org list" <email@example.com>
> Envoyé le : Mardi 15 janvier 2013 8h42
> Objet : [AstroPy] Missing some statistical method for your astronomy
> analyses in Python?
> Dear all,
> we would like to know which statistical methods you want to use for you
> astronomy work with Python that are not readily available e.g. in scipy or
> one of the existing scientific Python packages like e.g. statsmodels,
> scikit-learn, astroML, …
> Please visit the wiki page for what has already been suggested, then reply
> to this email or make an addition to the
> wiki page directly.
> The plan is to add these methods either to astropy.stats or, if they are not
> astronomy-specific, to one of the existing scientific Python packages.
> PS: This discussion started as a thread on astropy-dev (
> https://groups.google.com/d/topic/astropy-dev/Zwgafam171E/discussion ), but
> it was suggested to also ask here.
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