dolfin team mailing list archive

[A Navaei <axnavaei@xxxxxxxxxxxxxx>]

2009/2/19 Martin Sandve Alnæs <martinal@xxxxxxxxx>:
> On Thu, Feb 19, 2009 at 2:21 PM, A Navaei <axnavaei@xxxxxxxxxxxxxx> wrote:
>> 2009/2/19 Martin Sandve Alnæs <martinal@xxxxxxxxx>:
>>> Just a note: Images usually assume rectangular cells, dolfin currently
>>> only supports simplices.
>>
>> Since a rectangular simplicial mesh and triangulated simplicial mesh
>> share the nodes, it shouldn't be a problem. There is no link present
>> in image data structure, only nodes.
>
> So the images have values associated with the vertices, and not with the cells?

That's correct, here is a rectangular representation from the book
'Variational Methods in Imaging':

http://s5.tinypic.com/2gxeohh.jpg

When rectangular simplicial mesh is used, some people assign the image
value to the cells, and some use vertices. That's what it means by
'midpoints' in the text. In the triangular case, nodes (vertexes) are
the only option.


-Ali

>
> Martin
>