In my experience writing ndarray-like objects, you likely want to implement
__array__ instead of __array_interface__. The former gives you full control
to create the ndarray yourself.
On Fri, Mar 13, 2015 at 7:22 AM, Daniel Smith <dgasm...@icloud.com> wrote:
> Greetings everyone,
> I have a new project that deals with core and disk tensors wrapped into a
> single object so that the expressions are transparent to the user after the
> tensor is formed. I would like to add __array_interface__ to the core
> tensor and provide a reasonable error message if someone tries to call the
> __array_interface__ for a disk tensor. I may be missing something, but I do
> not see an obvious way to do this in the python layer.
>
> Currently I do something like:
>
> if ttype == “Core":
> self.__array_interface__ = self.tensor.ndarray_interface()
> else:
> self.__array_interface__ = {'typestr’: 'Only Core tensor
> types are supported.’}
>
> Which provides at least a readable error message if it is not a core
> tensor:
> TypeError: data type "Only Core tensor types are supported." not understood
>
> A easy solution I see is to change numpy C side __array_interface__ error
> message to throw custom strings.
>
> In numpy/core/src/multiarray/ctors.c:2100 we have the __array_interface__
> conversion:
>
> if (!PyDict_Check(iface)) {
> Py_DECREF(iface);
> PyErr_SetString(PyExc_ValueError,
> "Invalid __array_interface__ value, must be a dict");
> return NULL;
> }
>
> It could simply be changed to:
>
> if (!PyDict_Check(iface)) {
> if (PyString_Check(iface)){
> PyErr_SetString(PyExc_ValueError, iface);
> }
> else{
> PyErr_SetString(PyExc_ValueError,
> "Invalid __array_interface__ value, must be a dict”);
> }
> Py_DECREF(iface);
> return NULL;
> }
>
> Thoughts?
>
> Cheers,
> -Daniel Smith
> _______________________________________________
> NumPy-Discussion mailing list
> NumPy-Discussion@scipy.org
> http://mail.scipy.org/mailman/listinfo/numpy-discussion
>
_______________________________________________
NumPy-Discussion mailing list
NumPy-Discussion@scipy.org
http://mail.scipy.org/mailman/listinfo/numpy-discussion
