[AstroPy] Missing some statistical method for your astronomy analyses in Python?

Jerome Caron jerome_caron_astro at ymail.com
Tue Jan 15 04:51:53 EST 2013

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 <deil.christoph at googlemail.com>
À : "astropy at scipy.org list" <astropy at scipy.org> 
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 https://github.com/astropy/astropy/wiki/What-methods-do-we-want-in-astropy.stats?  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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