[Numpy-discussion] Sign of NaN

[Charles R Harris]

On Tue, Sep 29, 2015 at 6:58 PM, Chris Barker - NOAA Federal <
chris.barker at noaa.gov> wrote:

>
> One of the usecases that has sneaked in during the last few numpy versions
> is that object arrays contain numerical arrays where the shapes don't add
> up to a rectangular array.
>
>
> I think that's the wrong way to dve that problem -- we really should have
> a "proper" ragged array implementation. But is is the easiest way at this
> point.
>
> For this, and other use-cases, special casing Numpy arrays stored in
> object arrays does make sense:
>
> "If this is s a Numpy array, pass the operation through."
>

Because we now (development) use rich compare, the result looks like

In [1]: a = ones(3)

In [2]: b = array([a, -a], object)

In [3]: b
Out[3]:
array([[1.0, 1.0, 1.0],
       [-1.0, -1.0, -1.0]], dtype=object)

In [4]: sign(b)
Out[4]:
array([[1L, 1L, 1L],
       [-1L, -1L, -1L]], dtype=object)

The function returns long integers in order to not special case Python 3.
Hmm, wonder if we might want to change that.

Chuck
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