[SciPy-Dev] Adding a convenient method to create ufuncs in for scipy.stats

[Warren Weckesser]

On Thu, Mar 16, 2017 at 4:38 PM, Joshua Wilson <josh.craig.wilson at gmail.com>
wrote:

> ps--if we decide to abstract out the infrastructure I'd be willing to
> write the code.
>
>

Great!  I know you've been doing a lot of work in scipy.special, so you
probably know the code generation parts better than most of us.

Warren




> On Thu, Mar 16, 2017 at 3:28 PM, Joshua Wilson
> <josh.craig.wilson at gmail.com> wrote:
> >> Can we abstract out the build infrastructure to a common place?
> >
> > This should be fairly easy to do. It could be set up so that each
> > module that needs ufuncs could have a local config file (cribbed off
> > of the current `FUNCS` string in `generate_ufuncs.py`).
> >
> > Though I also don't object to adding more functions to special.
> >
> > On Thu, Mar 16, 2017 at 3:14 PM, Robert Kern <robert.kern at gmail.com>
> wrote:
> >> On Thu, Mar 16, 2017 at 12:39 PM, Warren Weckesser
> >> <warren.weckesser at gmail.com> wrote:
> >>>
> >>> On Thu, Mar 16, 2017 at 3:19 PM, Warren Weckesser
> >>> <warren.weckesser at gmail.com> wrote:
> >>>>
> >>>> I'm working on an update to the Frechet distribution in scipy.stats
> (see
> >>>> https://github.com/scipy/scipy/issues/3258 and
> >>>> https://github.com/scipy/scipy/pull/3275).
> >>>>
> >>>> Instead jumping through the "lazy_where" hoops that are required for
> >>>> conditional computations, it would be much easier to create a ufunc
> for the
> >>>> standard PDF, CDF and possibly other required functions.  Easier,
> that is,
> >>>> if I use the ufunc generation tools that we have over in
> scipy.special.
> >>>> Would there be any objections to this?  We already have quite a few
> >>>> functions for probability distributions in scipy.special:
> >>>> https://docs.scipy.org/doc/scipy/reference/special.html#
> raw-statistical-functions
> >>>>
> >>>> I wouldn't mind creating ufuncs for some of the other distributions,
> too.
> >>>> A ufunc implementation is more efficient, simplifies the code in
> >>>> scipy.stats, and automatically handles broadcasting.
> >>>>
> >>>> I'm bringing this up here to see if anyone has any objections to the
> >>>> expansion of the statistical functions in scipy.special.
> >>>>
> >>>> Warren
> >>>
> >>> In my previous email, the heading hints at an alternative that I didn't
> >>> mention in the text.  The question implied in the heading is: what do
> folks
> >>> think about adding ufunc generation tools to scipy.stats, instead of
> >>> generating the ufuncs in scipy.special.  There are a lot of conditional
> >>> computations in scipy.stats that would benefit from being implemented
> as
> >>> ufuncs, but probably don't need to be public functions.  So instead of
> >>> adding more functions to scipy.special, perhaps we could add code in
> >>> scipy.stats for generating ufuncs, many of which would be private.  Of
> >>> course, we could just generate private ufuncs in scipy.special, and
> only use
> >>> them in scipy.stats.
> >>
> >> +1 for adding additional more standard PDF/CDF functions to
> scipy.special as
> >> needed.
> >>
> >> There's already precedent for putting statistics-related but not
> >> distribution-related ufuncs into scipy.special, specifically for the
> >> conditional operations, e.g. boxcox(). On the other hand, if the
> functions
> >> you are thinking of would not be part of the public API, then I'd
> prefer to
> >> implement them in scipy.stats instead of scipy.special.
> >>
> >> What work do you think is entailed in implementing the ufuncs in
> >> scipy.stats? Is there infrastructure we need to duplicate? Can we
> abstract
> >> out the build infrastructure to a common place? I haven't looked at the
> >> build details for scipy.special in some time.
> >>
> >> --
> >> Robert Kern
> >>
> >> _______________________________________________
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> >> SciPy-Dev at scipy.org
> >> https://mail.scipy.org/mailman/listinfo/scipy-dev
> >>
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