[Numpy-discussion] Would a patch with a function for incrementing an array with advanced indexing be accepted?

John Salvatier jsalvati@u.washington....
Fri Jul 6 10:37:48 CDT 2012


Okay, done (
https://github.com/jsalvatier/numpy/commit/7d03753e6305dbc878ed7df3e21e9b099eae32ed
 ).



On Tue, Jul 3, 2012 at 11:41 AM, Frédéric Bastien <nouiz@nouiz.org> wrote:

> Hi,
>
> Here is code example that work only with different index:
>
> import numpy
> x=numpy.zeros((5,5))
> x[[0,2,4]]+=numpy.random.rand(3,5)
> print x
>
> This won't work if in the list [0,2,4], there is index duplication,
> but with your new code, it will. I think it is the most used case of
> advanced indexing. At least, for our lab:)
>
> Fred
>
> On Mon, Jul 2, 2012 at 7:48 PM, John Salvatier
> <jsalvati@u.washington.edu> wrote:
> > Hi Fred,
> >
> > That's an excellent idea, but I am not too familiar with this use case.
> What
> > do you mean by  list in 'matrix[list]'? Is the use case, just
> incrementing
> > in place a sub matrix of a numpy matrix?
> >
> > John
> >
> >
> > On Fri, Jun 29, 2012 at 11:43 AM, Frédéric Bastien <nouiz@nouiz.org>
> wrote:
> >>
> >> Hi,
> >>
> >> I personnaly can't review this as this is too much in NumPy internal.
> >>
> >> My only comments is that you could add a test and an example in the
> >> doc for matrix[list]. I think it will be the most used case.
> >>
> >> Fred
> >>
> >> On Wed, Jun 27, 2012 at 7:47 PM, John Salvatier
> >> <jsalvati@u.washington.edu> wrote:
> >> > I've submitted a pull request (
> https://github.com/numpy/numpy/pull/326
> >> > ).
> >> > I'm new to the numpy and python internals, so feedback is greatly
> >> > appreciated.
> >> >
> >> >
> >> > On Tue, Jun 26, 2012 at 12:10 PM, Travis Oliphant <
> travis@continuum.io>
> >> > wrote:
> >> >>
> >> >>
> >> >> On Jun 26, 2012, at 1:34 PM, Frédéric Bastien wrote:
> >> >>
> >> >> > Hi,
> >> >> >
> >> >> > I think he was referring that making NUMPY_ARRAY_OBJECT[...] syntax
> >> >> > support the operation that you said is hard. But having a separate
> >> >> > function do it is less complicated as you said.
> >> >>
> >> >> Yes. That's precisely what I meant.   Thank you for clarifying.
> >> >>
> >> >> -Travis
> >> >>
> >> >> >
> >> >> > Fred
> >> >> >
> >> >> > On Tue, Jun 26, 2012 at 1:27 PM, John Salvatier
> >> >> > <jsalvati@u.washington.edu> wrote:
> >> >> >> Can you clarify why it would be super hard? I just reused the code
> >> >> >> for
> >> >> >> advanced indexing (a modification of PyArray_SetMap). Am I missing
> >> >> >> something
> >> >> >> crucial?
> >> >> >>
> >> >> >>
> >> >> >>
> >> >> >> On Tue, Jun 26, 2012 at 9:57 AM, Travis Oliphant
> >> >> >> <travis@continuum.io>
> >> >> >> wrote:
> >> >> >>>
> >> >> >>>
> >> >> >>> On Jun 26, 2012, at 11:46 AM, John Salvatier wrote:
> >> >> >>>
> >> >> >>> Hello,
> >> >> >>>
> >> >> >>> If you increment an array using advanced indexing and have
> repeated
> >> >> >>> indexes, the array doesn't get repeatedly
> >> >> >>> incremented,
> >> >> >>>
> http://comments.gmane.org/gmane.comp.python.numeric.general/50291.
> >> >> >>> I wrote a C function that does incrementing with repeated indexes
> >> >> >>> correctly.
> >> >> >>> The branch is here (https://github.com/jsalvatier/numpy see the
> >> >> >>> last
> >> >> >>> two
> >> >> >>> commits). Would a patch with a cleaned up version of a function
> >> >> >>> like
> >> >> >>> this be
> >> >> >>> accepted into numpy? I'm not experienced writing numpy C code so
> >> >> >>> I'm
> >> >> >>> sure it
> >> >> >>> still needs improvement.
> >> >> >>>
> >> >> >>>
> >> >> >>> This is great.   It is an often-requested feature.   It's *very
> >> >> >>> difficult*
> >> >> >>> to do without changing fundamentally what NumPy is.  But, yes
> this
> >> >> >>> would be
> >> >> >>> a great pull request.
> >> >> >>>
> >> >> >>> Thanks,
> >> >> >>>
> >> >> >>> -Travis
> >> >> >>>
> >> >> >>>
> >> >> >>>
> >> >> >>> _______________________________________________
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> >> >> >>>
> >> >> >>
> >> >> >>
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