Re: [Numpy-discussion] Changes in PyArray_FromAny between 1.5.x and 1.6.x
On Tue, Jun 5, 2012 at 8:34 AM, Nathaniel Smith wrote:
> I don't think that would work, because looking more closely, I don't
> think they're actually doing anything like what
> __array_interface__/PEP3118 are designed for. They just have some
> custom class ("sage.rings.real_mpfr.RealLiteral", I guess an arbitrary
> precision floating point of some sort?), and they want instances that
> are passed to np.array() to be automatically coerced to another type
> (float64) by default. But there's no buffer sharing or anything like
> that going on at all. Mike, does that sound right?
Yes, there's no buffer sharing going on at all.
> This automagic coercion seems... in very dubious taste to me. (Why
> does creating an array object imply that you want to throw away
> precision?
The __array_interface__ attribute is a property which depends on the
precision of the ring. If it floats have enough precision, you just
get floats; otherwise you get objects.
> You can already throw away precision explicitly by doing
> np.array(f, dtype=float).) But if this automatic coercion feature is
> useful, then wouldn't it be better to have a different interface
> instead of kluging it into __array_interface__, like we should check
> for an attribute called __numpy_preferred_dtype__ or something?
It isn't just the array() calls which end up getting problems. For
example, in 1.5.x
sage: f = 10; type(f)
sage: numpy.arange(f)
array([0, 1, 2, 3, 4, 5, 6, 7, 8, 9]) #int64
while in 1.6.x
sage: numpy.arange(f)
array([0, 1, 2, 3, 4, 5, 6, 7, 8, 9], dtype=object)
We also see problems with calls like
sage: scipy.stats.uniform(0,15).ppf([0.5,0.7])
array([ 7.5, 10.5])
which work in 1.5.x, but fail with a traceback "TypeError: array
cannot be safely cast to required type" in 1.6.x.
--Mike
___
NumPy-Discussion mailing list
NumPy-Discussion@scipy.org
http://mail.scipy.org/mailman/listinfo/numpy-discussion
Re: [Numpy-discussion] Changes in PyArray_FromAny between 1.5.x and 1.6.x
On Mon, Jun 4, 2012 at 9:30 PM, Travis Oliphant wrote: > Can you raise an issue on the Github issue tracker for NumPy? These issues > will be looked at more closely. This kind of change should not have made it > in to the release. Thanks Travis! I've made this https://github.com/numpy/numpy/issues/291 --Mike ___ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
Re: [Numpy-discussion] Changes in PyArray_FromAny between 1.5.x and 1.6.x
On Mon, May 28, 2012 at 3:15 AM, Mike Hansen wrote:
> In trying to upgrade NumPy within Sage, we notices some differences in
> behavior between 1.5 and 1.6. In particular, in 1.5, we have
>
> sage: f = 0.5
> sage: f.__array_interface__
> {'typestr': '=f8'}
> sage: numpy.array(f)
> array(0.5)
> sage: numpy.array(float(f))
> array(0.5)
>
> In 1.6, we get the following,
>
> sage: f = 0.5
> sage: f.__array_interface__
> {'typestr': '=f8'}
> sage: numpy.array(f)
> array(0.500, dtype=object)
>
> This seems to be do to the changes in PyArray_FromAny introduced in
> https://github.com/mwhansen/numpy/commit/2635398db3f26529ce2aaea4028a8118844f3c48
> . In particular, _array_find_type used to be used to query our
> __array_interface__ attribute, and it no longer seems to work. Is
> there a way to get the old behavior with the current code?
Any ideas?
Thanks,
--Mike
___
NumPy-Discussion mailing list
NumPy-Discussion@scipy.org
http://mail.scipy.org/mailman/listinfo/numpy-discussion
[Numpy-discussion] Changes in PyArray_FromAny between 1.5.x and 1.6.x
Hello,
In trying to upgrade NumPy within Sage, we notices some differences in
behavior between 1.5 and 1.6. In particular, in 1.5, we have
sage: f = 0.5
sage: f.__array_interface__
{'typestr': '=f8'}
sage: numpy.array(f)
array(0.5)
sage: numpy.array(float(f))
array(0.5)
In 1.6, we get the following,
sage: f = 0.5
sage: f.__array_interface__
{'typestr': '=f8'}
sage: numpy.array(f)
array(0.500, dtype=object)
This seems to be do to the changes in PyArray_FromAny introduced in
https://github.com/mwhansen/numpy/commit/2635398db3f26529ce2aaea4028a8118844f3c48
. In particular, _array_find_type used to be used to query our
__array_interface__ attribute, and it no longer seems to work. Is
there a way to get the old behavior with the current code?
--Mike
___
NumPy-Discussion mailing list
NumPy-Discussion@scipy.org
http://mail.scipy.org/mailman/listinfo/numpy-discussion
