Re: [Numpy-discussion] Behavior of array scalars

[Sasha <nd...@ma...>]

On 2/17/06, Travis Oliphant <oli...@ee...> wrote:
> ...
> Perhaps what is going on is that
> a +=3D 10
> is begin translated to
> a =3D a + 10
> rather than
> add(a,10,a)
> I'll have to look deeper to see why.

It is actually being translated to "a =3D add(a,10,a)" by virtue of
array_inplace_add supplied in the inplace_add slot.  Here is the
proof:

>>> a =3D array(0)
>>> a =3D b =3D array(0)
>>> a +=3D 10
>>> b
array(10)
>>> a
10

Another way to explain it is to note that a +=3D 10 is equivalent to "a
=3D a.__iadd__(10)" and a.__iadd__(10) is equivalent to "add(a, 10, a)".

This is not easy to fix because the real culprit is

>>> a =3D array(0)
>>> type(a) is type(a+a)
False

Maybe we can change ufunc logic so that when the output argument is
supplied it is returned without scalar conversion.