Hi all,
in https://github.com/numpy/numpy/pull/3514 I proposed some changes to the comparison operators. This includes:
1. Comparison with None will broadcast in the future, so that `arr == None` will actually compare all elements to None. (A FutureWarning for now)
2. I added that == and != will give FutureWarning when an error was raised. In the future they should not silence these errors anymore. (For example shape mismatches)
3. We used to use PyObject_RichCompareBool for equality which includes an identity check. I propose to not do that identity check since we have elementwise equality (returning an object array for objects would be nice in some ways, but I think that is only an option for a dedicated function). The reason is that for example
a = np.array([np.array([1, 2, 3]), 1]) b = np.array([np.array([1, 2, 3]), 1]) a == b
will happen to work if it happens to be that `a[0] is b[0]`. This currently has no deprecation, since the logic is in the inner loop and I am not sure if it is easy to add well there.
Are there objections/comments to these changes?
Regards,
Sebastian
On 25 Jan 2014 00:05, "Sebastian Berg" sebastian@sipsolutions.net wrote:
Hi all,
in https://github.com/numpy/numpy/pull/3514 I proposed some changes to the comparison operators. This includes:
 Comparison with None will broadcast in the future, so that `arr ==
None` will actually compare all elements to None. (A FutureWarning for now)
 I added that == and != will give FutureWarning when an error was
raised. In the future they should not silence these errors anymore. (For example shape mismatches)
This can just be a DeprecationWarning, because the only change is to raise new more errors.
 We used to use PyObject_RichCompareBool for equality which includes
an identity check. I propose to not do that identity check since we have elementwise equality (returning an object array for objects would be nice in some ways, but I think that is only an option for a dedicated function). The reason is that for example
a = np.array([np.array([1, 2, 3]), 1]) b = np.array([np.array([1, 2, 3]), 1]) a == b
will happen to work if it happens to be that `a[0] is b[0]`. This currently has no deprecation, since the logic is in the inner loop and I am not sure if it is easy to add well there.
Surely any environment where we can call PyObject_RichCompareBool is an environment where we can issue a warning...?
n
On Sat, 20140125 at 00:18 +0000, Nathaniel Smith wrote:
On 25 Jan 2014 00:05, "Sebastian Berg" sebastian@sipsolutions.net wrote:
Hi all,
in https://github.com/numpy/numpy/pull/3514 I proposed some changes
to
the comparison operators. This includes:
 Comparison with None will broadcast in the future, so that `arr
==
None` will actually compare all elements to None. (A FutureWarning
for
now)
 I added that == and != will give FutureWarning when an error was
raised. In the future they should not silence these errors anymore.
(For
example shape mismatches)
This can just be a DeprecationWarning, because the only change is to raise new more errors.
Right, already is the case.
 We used to use PyObject_RichCompareBool for equality which
includes
an identity check. I propose to not do that identity check since we
have
elementwise equality (returning an object array for objects would be nice in some ways, but I think that is only an option for a
dedicated
function). The reason is that for example
a = np.array([np.array([1, 2, 3]), 1]) b = np.array([np.array([1, 2, 3]), 1]) a == b
will happen to work if it happens to be that `a[0] is b[0]`. This currently has no deprecation, since the logic is in the inner loop
and I
am not sure if it is easy to add well there.
Surely any environment where we can call PyObject_RichCompareBool is an environment where we can issue a warning...?
Right, I suppose an extra identity check and comparing it with the other result is indeed no problem. So I think I will add that.
 Sebastian
n
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participants (3)

Nathaniel Smith

Sebastian Berg

Stéfan van der Walt