[Numpy-discussion] Adjacent matrix

[Gael Varoquaux]

On Tue, Jun 14, 2011 at 10:29:38AM -0300, Thiago Franco Moraes wrote:
> I don't know if I understand. The idea is to use _make_edges_3d to
> give me the connectivity, isn't it? Like for example, a 3x3 image:

> 0, 1, 2
> 3, 4, 5
> 6, 7, 8

> If I use _make_edges_3d(3, 3) I get:

> array([[0, 1, 3, 4, 6, 7, 0, 1, 2, 3, 4, 5],
>        [1, 2, 4, 5, 7, 8, 3, 4, 5, 6, 7, 8]])

> So, for example, the pixel 4 is connected with 3, 5, 7 and 1
> (connectivity 4). Is it?

Yes, you go the idea.

> The problem is I need to work with connectivity 26 in 3D images, or 8
> in 2D images. I'm not able to understand the code so well to apply to
> those connectivity I said (8 and 26).

The code is for 4 connectivity (or 6 in 3D). You will need to modify the
_make_edges_3d function to get the connectivity you want. Hopefully this
will get the ball running, and by looking at the code you will figure out
how to modify it.

HTH, 

Gaël