[petsc-users] sieve-dev Data shared between points in a Sieve DAG

[Matthew Knepley]

On Wed, Jul 25, 2012 at 12:52 PM, Chris Eldred <chris.eldred at gmail.com>wrote:

> The closure operation makes sense, but what I want is something a little
> different.
>
> I have a field that is defined as follows:
> field(edge,cell) = blah
> ie it really lives on the union of cells and edges (or vertex/edges,
> cells/vertexs, etc.)
>

We need to make the language more precise. The union of the cell and edge
is what
closure would give you.


> Is this something that can be defined using DMComplex and Sections?


I cannot understand from this explanation. Can you give a small example?

  Thanks,

     Matt


> On Wed, Jul 25, 2012 at 11:39 AM, Matthew Knepley <knepley at gmail.com>wrote:
>
>> On Wed, Jul 25, 2012 at 11:23 AM, Chris Eldred <chris.eldred at gmail.com>wrote:
>>
>>> I was wondering if it was possible to have fields that are shared
>>> between points in a sieve DAG:
>>>
>>> For example, I would like to have data that is connected to both an edge
>>> and a cell (instead of just tied to a Section). Consider a cell with three
>>> edges (ie a triangular cell).
>>>
>>> Before I was just using a length 3 array attached to the cell with the
>>> convention that the ordering of the array matched the ordering of the edge
>>> list associated with the cell. Now, I would like an implementation that
>>> does not assume anything about the ordering of the edge list (since I am
>>> getting that from cones/supports).
>>>
>>
>> I think what you want is the Closure operation. The closure of a cell
>> will give you all the unknowns on its edges and vertices.
>> Does that make sense?
>>
>>   Thanks,
>>
>>      Matt
>>
>>
>>> Thanks,
>>> -Chris Eldred
>>>
>>> --
>>> Chris Eldred
>>> DOE Computational Science Graduate Fellow
>>> Graduate Student, Atmospheric Science, Colorado State University
>>> B.S. Applied Computational Physics, Carnegie Mellon University, 2009
>>> chris.eldred at gmail.com
>>>
>>
>>
>>
>> --
>> What most experimenters take for granted before they begin their
>> experiments is infinitely more interesting than any results to which their
>> experiments lead.
>> -- Norbert Wiener
>>
>
>
>
> --
> Chris Eldred
> DOE Computational Science Graduate Fellow
> Graduate Student, Atmospheric Science, Colorado State University
> B.S. Applied Computational Physics, Carnegie Mellon University, 2009
> chris.eldred at gmail.com
>



-- 
What most experimenters take for granted before they begin their
experiments is infinitely more interesting than any results to which their
experiments lead.
-- Norbert Wiener
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