[pythran] Re: ndarray
- From: Neal Becker <ndbecker2@xxxxxxxxx>
- To: pythran@xxxxxxxxxxxxx
- Date: Fri, 29 Aug 2014 18:32:03 -0400
Silently producing wrong results is a bad thing
with ndarray, the c++ code can specify the minimum # contiguous dimensions
it will accept. If it expects a dense array, for example,
Array<int,2,2>
and is passed an array that is not contiguous,
x[:,::2],
then boost::python will complain about being unable to convert. Not a very
good error message, but at least you get a message.
You could even put 2 versions of your routine (or for that matter, M
versions) - such as one that accepts only dense arrays and another that
works for general strides.
At a minimum, an error message should be produced at runtime.
The best behavior would be for pythran to handle both strided and
non-strided arrays correctly, and as efficiently as possible. But I have
no idea how difficult that would be.
On Fri, Aug 29, 2014 at 4:50 PM, serge Guelton <sguelton@xxxxxxxxxxxxx>
wrote:
> > Just for information. On your example:
> >
> > #export sum(int[])
> > def sum (x):
> >
> > We will *assum* that x is contiguous.
> >
> > If you use : sum(a[::2]), you will have an incorrect output.
> > It can be fix if you need this kind of use.
>
> Correct. We should open a ticket on this one...
>
>
--
*Those who don't understand recursion are doomed to repeat it*
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