[Numpy-discussion] 1.6.0b1 half float buffer bug?

Eli Stevens (Gmail) wickedgrey@gmail....
Fri Mar 25 13:12:10 CDT 2011


On Fri, Mar 25, 2011 at 10:21 AM, Pauli Virtanen <pav@iki.fi> wrote:
> The buffer interface cannot be used to export the half-float types, since
> the type is not specified in PEP 3118. Numpy cannot unilaterally add
> nonstandard format codes to the spec.
>
> What can be done instead is exporting the half-float items (and any other
> non-3118 types) as plain bytes. I think this is the way to go.

What about as uint16s?  Won't plain bytes have endian issues?

case NPY_HALF:         if (_append_char(str, 'H')) return -1; break;

Something like that?  I am also still curious about where unit tests
for things like this should go.

> On the Cython side, you'd need to detect when you are working with Numpy
> arrays, and get the half-float type information from the Numpy dtype
> rather than from the exported buffer.

Hrm, okay.  I'll have to follow up with the Cython folks about that.
I hope that my fears about that ending up being a sweeping change are
unfounded (having already gone through and made the changes to
unilaterally add support for 'e' buffer types, it seems like it's
baked in; we'll see).  :-/

Thanks,
Eli


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