[Cython] Fused type signature resolution failures

[Pauli Virtanen]

22.06.2014 13:48, Stefan Behnel kirjoitti:
[clip]
> > (A)
[clip]
> > asd.foo(np.float32(1.0))
>
> I don't actually know how NumPy represents its types at the Python
> level, but my guess is that it would be tricky to match these two
> without teaching Cython itself something about NumPy (and how it
> wraps basic C types here). I'd rather like to avoid that and live
> with the above.

Agreed, it's probably not possible to properly deal with this without
making use of Numpy scalar type object binary layout in some form.

On the other hand, `asd.foo(np.array(1.0))` doesn't work either ---
maybe the buffer code path does not trigger for scalar values.

[clip]
>> (B)
>>
>> ValueError: Buffer dtype mismatch, expected 'int64_t' but got 'double'
[clip]
> This looks like a bug to me at first sight.

This was fixed by my PR #284 that you merged.

>> (C)
>>
>> Then some nasty platform-dependent failures:
[clip]
> Generally speaking, I think that the signature matching algorithm has some
> room for improvements, especially the one that matches Python signatures at
> runtime.
> 
> We should take a look at how other implementations do this dispatch. There
> are multiple "generic functions" implementations for Python that do similar
> things.

I agree that there probably is room for improvement, possibly also
speed-wise.

I'll try to revisit (at some point) the csparsetools Cython
implementation to see if there are low-hanging fixes that would be
useful there.

-- 
Pauli Virtanen