[Numpy-discussion] dtype subarray comparison

Mark Wiebe mwwiebe@gmail....
Thu Oct 21 16:25:24 CDT 2010


On Thu, Oct 21, 2010 at 2:11 PM, Pauli Virtanen <pav@iki.fi> wrote:

> <snip>
>
> Also, it is not correct to assume the dimensions are added to the end:
>
> >>> x = np.zeros((2,3),dtype=[('a','f8',(4,))]).T
> >>> x.shape
> (3, 2)
> >>> x['a'].shape
> (4, 3, 2)
>
> There's a special branch in the field access code that does this for
> Fortran-order arrays. Or, more precisely, arrays with the fortran-order
> flag set. (IIRC, there are some ways to create arrays in Fortran order so
> that the flag does not get set.)
>
> This seems to be somewhat of a mis-feature to me -- it makes predicting
> code behavior difficult to anticipate.
>

That sounds like it could be tricky to handle correctly, especially since it
should probably work to compare Fortran-order arrays with non-Fortran ones.
 Does anything actually depend on this behavior?  Maybe it's something that
could change?

-Mark
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mail.scipy.org/pipermail/numpy-discussion/attachments/20101021/0e0b61ca/attachment.html 


More information about the NumPy-Discussion mailing list