[Numpy-discussion] Adding weights to cov and corrcoef

Thu Mar 6 14:27:01 EST 2014

Date: Thu, 06 Mar 2014 13:40:40 +0100

> From: Sebastian Berg <sebastian at sipsolutions.net>
> Subject: Re: [Numpy-discussion] Adding weights to cov and corrcoef
>         (Sebastian Berg)
> To: numpy-discussion at scipy.org
> Message-ID: <1394109640.9122.13.camel at sebastian-t440>
> Content-Type: text/plain; charset="UTF-8"
>
> On Mi, 2014-03-05 at 10:21 -0800, David Goldsmith wrote:
> > +1 for it being "too baroque" for NumPy--should go in SciPy (if it
> > isn't already there): IMHO, NumPy should be kept as "lean and mean" as
> > possible, embellishments are what SciPy is for.  (Again, IMO.)
> >
>
> Well, on the other hand, scipy does not actually have a `std` function
> of its own, I think.

Oh, well, in that case forget I said anything.  (Though I think it's
"interesting" that no one else has chimed in: if you're the only one that
needs it (at this time), perhaps it would be best to "roll your own" and
then offer to "pass it around." :-))

DG

> So if it is quite useful I think this may be an
> option (I don't think I ever used weights with std, so I can't argue
> strongly for inclusion myself). Unless adding new functions to
> `scipy.stats` (or just statsmodels) which implement different types of
> weights is the longer term plan, then things might bite...
>
> > DG
> > _______________________________________________
> > NumPy-Discussion mailing list
> > NumPy-Discussion at scipy.org
> > http://mail.scipy.org/mailman/listinfo/numpy-discussion
>
>
>
>
> ------------------------------
>
> Message: 5
> Date: Thu, 6 Mar 2014 13:45:36 +0000
> From: Nathaniel Smith <njs at pobox.com>
> Subject: Re: [Numpy-discussion] numpy gsoc ideas (was: numpy gsoc
>         topic idea: configurable algorithm precision and vector math
> library
>         integration)
> To: Discussion of Numerical Python <numpy-discussion at scipy.org>
> Message-ID:
>         <CAPJVwBm=no71WvC9Zjh7DXNaGn0jpAGmvrOyoVvmHK-MW=
> R3Fw at mail.gmail.com>
> Content-Type: text/plain; charset=UTF-8
>
> On Thu, Mar 6, 2014 at 5:17 AM, Sturla Molden <sturla.molden at gmail.com>
> wrote:
> > Nathaniel Smith <njs at pobox.com> wrote:
> >
> >> 3. Using Cython in the numpy core
> >>
> >> The numpy core contains tons of complicated C code implementing
> >> elaborate operations like indexing, casting, ufunc dispatch, etc. It
> >> would be really nice if we could use Cython to write some of these
> >> things.
> >
> > So the idea of having a NumPy as a pure C library in the core is
> abandoned?
>
> This question doesn't make sense to me so I think I must be missing
> some context.
>
> Nothing is abandoned: This is one email by one person on one mailing
> list suggesting a project to the explore the feasibility of something.
> And anyway, Cython is just a C code generator, similar in principle to
> (though vastly more sophisticated than) the ones we already use. It's
> not like we've ever promised our users we'll keep stable which kind of
> code generators we use internally.
>
> >>  However, there is a practical problem: Cython assumes that
> >> each .pyx file generates a single compiled module with its own
> >> Cython-defined API. Numpy, however, contains a large number of .c
> >> files which are all compiled together into a single module, with its
> >> own home-brewed system for defining the public API. And we can't
> >> rewrite the whole thing. So for this to be viable, we would need some
> >> way to compile a bunch of .c *and .pyx* files together into a single
> >> module, and allow the .c and .pyx files to call each other.
> >
> > Cython takes care of that already.
> >
> > http://docs.cython.org/src/userguide/sharing_declarations.html#cimport
> >
> >
> http://docs.cython.org/src/userguide/external_C_code.html#using-cython-declarations-from-c
>
> Linking multiple .c and .pyx files together into a single .so/.dll is
> much more complicated than just using 'cimport'. Try it if you don't
> believe me :-).
>
> -n
>
> --
> Nathaniel J. Smith
> Postdoctoral researcher - Informatics - University of Edinburgh
> http://vorpus.org
>
>
> ------------------------------
>
> Message: 6
> Date: Thu, 6 Mar 2014 13:59:30 +0000
> From: Nathaniel Smith <njs at pobox.com>
> Subject: Re: [Numpy-discussion] numpy gsoc ideas (was: numpy gsoc
>         topic idea: configurable algorithm precision and vector math
> library
>         integration)
> To: Discussion of Numerical Python <numpy-discussion at scipy.org>
> Message-ID:
>         <CAPJVwB=PmquKm5j4-oquCkLkcK8G1pipB8XLbq5=
> 26izjbJPjg at mail.gmail.com>
> Content-Type: text/plain; charset=UTF-8
>
> On Thu, Mar 6, 2014 at 9:11 AM, David Cournapeau <cournape at gmail.com>
> wrote:
> >
> > On Wed, Mar 5, 2014 at 9:11 PM, Nathaniel Smith <njs at pobox.com> wrote:
> >> So this project would have the following goals, depending on how
> >> practical this turns out to be: (1) produce a hacky proof-of-concept
> >> system for doing the above, (2) turn the hacky proof-of-concept into
> >> something actually viable for use in real life (possibly this would
> >> require getting changes upstream into Cython, etc.), (3) use this
> >> system to actually port some interesting numpy code into cython.
> >
> >
> > Having to synchronise two projects may be hard for a GSoC, no ?
>
> Yeah, if someone is interested in this it would be nice to get someone
> from Cython involved too. But that's why the primary goal is to
> produce a proof-of-concept -- even if all that comes out is that we
> learn that this cannot be done in an acceptable manner, then that's
> still a succesful (albeit disappointing) result.
>
> > Otherwise, I am a bit worried about cython being used on the current C
> code
> > as is, because core and python C API are so interwined (especially
> > multiarray).
>
> I don't understand this objection. The whole advantage of Cython is
> that it makes it much, much easier to write code that involves
> intertwining complex algorithms and heavy use of the Python C API :-).
> There's tons of bug-prone spaghetti in numpy for doing boring things
> like refcounting, exception passing, and argument parsing.
>
> -n
>
> --
> Nathaniel J. Smith
> Postdoctoral researcher - Informatics - University of Edinburgh
> http://vorpus.org
>
>
> ------------------------------
>
> Message: 7
> Date: Thu, 6 Mar 2014 10:35:15 -0700
> From: Charles R Harris <charlesr.harris at gmail.com>
> Subject: Re: [Numpy-discussion] 1.8.1rc1 on sourceforge.
> To: Discussion of Numerical Python <numpy-discussion at scipy.org>
> Message-ID:
>         <
> CAB6mnx+btuF3vKxvebfBZKybggp+C6mtnb7zD1ck1bqk9VXV2w at mail.gmail.com>
> Content-Type: text/plain; charset="iso-8859-1"
>
> On Wed, Mar 5, 2014 at 7:28 PM, Matthew Brett <matthew.brett at gmail.com
> >wrote:
>
> > Hi,
> >
> > On Wed, Mar 5, 2014 at 3:29 PM, Matthew Brett <matthew.brett at gmail.com>
> > wrote:
> > > Hi,
> > >
> > > I built (and tested) some numpy wheels for the rc1:
> > >
> > > http://nipy.bic.berkeley.edu/numpy-dist/
> >
> > Now building, installing, testing, uploading wheels nightly on OSX 10.9:
> >
> > http://nipy.bic.berkeley.edu/builders/numpy-bdist-whl-osx-2.7
> > http://nipy.bic.berkeley.edu/builders/numpy-bdist-whl-osx-3.3
> >
> > and downloading, testing built wheels on OSX 10.6:
> >
> > http://nipy.bic.berkeley.edu/builders/numpy-bdist-whl-osx-2.7-downloaded
> > http://nipy.bic.berkeley.edu/builders/numpy-bdist-whl-osx-3.3-downloaded
> >
> > Chuck - are you release manager for this cycle?  Would you mind
> > sending me your public ssh key so I can give you access to the
> > buildbots for custom builds and so on?
> >
> > Cheers,
> >
> >
> Julian has done most of the work for 1.8.1. I did the 1.8.0 release because
> it needed doing, but building releases isn't my strong point and Ralf
> actually did the builds for that. So I'll happily send you my ssh, but
> either Ralph or Julian might be a better bet for getting the work done :)
>
> Chuck
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