[Numpy-discussion] NEP for faster ufuncs

Mark Wiebe mwwiebe@gmail....
Wed Dec 22 10:25:13 CST 2010


On Wed, Dec 22, 2010 at 12:54 AM, Francesc Alted <faltet@pytables.org>wrote:

> A Wednesday 22 December 2010 09:48:03 Mark Wiebe escrigué:
> > On Wed, Dec 22, 2010 at 12:21 AM, Francesc Alted
> <faltet@pytables.org>wrote:
> > > <snip>
>  > > new_iterator branch does not work for me; it gives me an error
> > > like: AttributeError: 'module' object has no attribute 'newiter'),
> >
> > What are you using to build it?  So far I've just modified the
> > setup.py scripts, I still need to add it to numscons.
>
> Well, just the typical "git clone ...; python setup.py install" dance.
>

Can you print out your np.__version__, and try running the tests?  If
newiter didn't build for some reason, its tests should be throwing a bunch
of exceptions.


> > > i.e. numexpr is not able to achieve the 2x speedup mark that you
> > > are getting with ``luf`` (using a Core2 @ 3 GHz here).
> >
> > That's promising!  I based my assertion on getting a slower speedup
> > than numexpr does on their front page example.
>
> I see :-)  Well, I'd think that numexpr is not specially efficient when
> handling broadcasting, so this might be the reason your approach is
> faster.  I suppose that with operands with the same shape, things might
> look different.
>

I haven't looked at the numexpr code, but I think the ufuncs will need SSE
versions to make up part of the remaining difference.

-Mark
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