[Numpy-discussion] Neighborhood iterator: way to easily check which elements have already been visited in parent iterator?

[Thouis (Ray) Jones]

Hello,

I'm rewriting scipy.ndimage.label() using numpy's iterator API, and
would like to add the ability for it to operate in-place.  However, to
do so, I need to limit the neighbors consulted to those that have
already been processed in the parent iterator over the input and
output arrays.  Is there a general way to do this?

If the parent iterator is constructed with the default flags
(order='K' and readonly), can I assume that it will always move
forward in memory?

Thanks for any advice,
Ray Jones