[Numpy-discussion] New numpy functions: filled, filled_like

Thouis (Ray) Jones thouis@gmail....
Thu Jan 17 22:05:14 CST 2013


On Jan 17, 2013 8:01 PM, "Olivier Delalleau" <shish@keba.be> wrote:
>
> 2013/1/17 Matthew Brett <matthew.brett@gmail.com>:
> > Hi,
> >
> > On Thu, Jan 17, 2013 at 10:27 PM, Mark Wiebe <mwwiebe@gmail.com> wrote:
> >>
> >> On Thu, Jan 17, 2013 at 2:10 PM, Benjamin Root <ben.root@ou.edu> wrote:
> >>>
> >>>
> >>>
> >>> On Thu, Jan 17, 2013 at 5:04 PM, Eric Firing <efiring@hawaii.edu>
wrote:
> >>>>
> >>>> On 2013/01/17 4:13 AM, Pierre Haessig wrote:
> >>>> > Hi,
> >>>> >
> >>>> > Le 14/01/2013 20:05, Benjamin Root a écrit :
> >>>> >> I do like the way you are thinking in terms of the broadcasting
> >>>> >> semantics, but I wonder if that is a bit awkward.  What I mean
is, if
> >>>> >> one were to use broadcasting semantics for creating an array,
wouldn't
> >>>> >> one have just simply used broadcasting anyway?  The point of
> >>>> >> broadcasting is to _avoid_ the creation of unneeded arrays.  But
maybe
> >>>> >> I can be convinced with some examples.
> >>>> >
> >>>> > I feel that one of the point of the discussion is : although a new
(or
> >>>> > not so new...) function to create a filled array would be more
elegant
> >>>> > than the existing pair of functions "np.zeros" and "np.ones",
there are
> >>>> > maybe not so many usecases for filled arrays *other than zeros
values*.
> >>>> >
> >>>> > I can remember having initialized a non-zero array *some months
ago*.
> >>>> > For the anecdote it was a vector of discretized vehicule speed
values
> >>>> > which I wanted to be initialized with a predefined mean speed value
> >>>> > prior to some optimization. In that usecase, I really didn't care
about
> >>>> > the performance of this initialization step.
> >>>> >
> >>>> > So my overall feeling after this thread is
> >>>> >   - *yes* a single dedicated fill/init/someverb function would
give a
> >>>> > slightly better API,
> >>>> >   -  but *no* it's not important because np.empty and np.zeros
covers
> >>>> > 95
> >>>> > % usecases !
> >>>>
> >>>> I agree with your summary and conclusion.
> >>>>
> >>>> Eric
> >>>>
> >>>
> >>> Can we at least have a np.nans() and np.infs() functions?  This should
> >>> cover an additional 4% of use-cases.
> >>>
> >>> Ben Root
> >>>
> >>> P.S. - I know they aren't verbs...
> >>
> >>
> >> Would it be too weird or clumsy to extend the empty and empty_like
functions
> >> to do the filling?
> >>
> >> np.empty((10, 10), fill=np.nan)
> >> np.empty_like(my_arr, fill=np.nan)
> >
> > That sounds like a good idea to me.  Someone wanting a fast way to
> > fill an array will probably check out the 'empty' docstring first.
> >
> > See you,
> >
> > Matthew
>
> +1 from me. Even though it *is* weird to have both "empty" and "fill" ;)

I'd almost prefer such a keyword be added to np.ones() to avoid that
weirdness.

(something like "an array of ones where one equals X")

Ray
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