[Numpy-discussion] Ready for review: PyArrayNeighIterObject, an iterator to iterate over a neighborhood in arbitrary arrays

[Charles R Harris]

On Sat, Jun 13, 2009 at 7:46 AM, David Cournapeau <
david at ar.media.kyoto-u.ac.jp> wrote:
>
> Hi,
>
>    I have cleaned up a bit the code, and would like to suggest the
> inclusion of a neighborhood iterator for numpy. Stéfan took a look at it
> already, but it needs more eyeballs. It is a "subclass" of
> PyArrayIterObject, and can be used to iterate over a neighborhood of a
> point (handling boundaries with 0 padding for the time being).
>
> http://codereview.appspot.com/75055/show
>
> I have used it to replace the current for code correlateND in
> scipy.signal, where it works quite well (I think it makes the code more
> readable in that case).

Some nitpicks:

1) The name neigh sounds like a horse. Maybe region,  neighborhood, or
something similar would be better.

2) Is PyObject_Init NULL safe?

ret = PyArray_malloc(sizeof(*ret));
+    PyObject_Init((PyObject*)ret,&PyArrayNeighIter_Type);
+    if (ret == NULL) {
+        return NULL;
+    }

3) Documentation is needed. In particular, I think it worth mentioning that
the number of bounds is taken from the PyArrayIterObject, which isn't the
most transparent thing.

Otherwise, looks good.

Chuck
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