[AstroPy] Problem with astropy 03 and quantities
kyle at anl.gov
Sun Nov 24 19:16:53 EST 2013
I'll let others answer your main question, but to answer the PS, there is a
discussion of the performance hit to astropy.cosmology due to using
Note however that Quantity has seen some optimization since this
discussion, so the timings there probably aren't applicable any more.
On Sun, Nov 24, 2013 at 5:50 PM, Yannick Roehlly <yannick.roehlly at lam.fr>wrote:
> Dear all,
> I've encountered a problem with astropy 0.3 and I wonder how to solve
> it and if it's an astropy issue or not.
> I've got some code (a SED fitting code) that used to work with astropy
> 0.2.5 and no longer works with version 0.3, failing with a "ValueError:
> setting an array element with a sequence." when trying to copy an array
> with numpy.copy.
> I managed to trace the problem. At some point, I'm using the cosmology
> module to compute a luminosity distance while building an array of
> fluxes. With astropy 0.3, the luminosity_distance functions returns
> quantities. So I have a "quantified" array that can not be copied with
> So, I wonder if there is a way to disable this behaviour and make
> astropy not use quantities.
> Also, I wonder if this is not an astropy issue as it breaks working
> code (at least, there should be a warning in the changelog).
> PS: Does the use of quantities slows down the computation or their
> effect is negligible?
> Wernher von Braun settled for a V-2 when he coulda had a V-8.
> AstroPy mailing list
> AstroPy at scipy.org
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