Re: [Libmesh-users] Material number and other tags.

[Kirk, B. (JSC-EG) <Ben...@na...>]

I'll dump some quick thoughts and then follow up some more later....

From my perspective, the current DofObjects are too heavy.  This especially  true in the common case of lagrange elements, as the dof indexing is never used for elements.  So I am hesitant to add anything...

At the same time, there is no way the library can pack arbitrary data for communication without user help...


What I was thinking as an alternative is - gasp - templates.  Specifically, temnplating on the DofObjectType used for both Elem an Nodes.  The UnstruturedMesh is then a typedef for UnstructuredMeshImpl<DofObject,DofObject> or something.

But the benefit is that the user is free to implement derived DofObject types which store whatever, implement additiona packing/unpacking as required, then use UnstructuredMeshImpl<FatDofObject, SkinnyDofObject> or whatever...

Thoughts?

Let the stone throwing begin...

-Ben


  



----- Original Message -----
From: Vijay S. Mahadevan <vi...@gm...>
To: lib...@li... <lib...@li...>
Sent: Tue Feb 10 13:21:13 2009
Subject: [Libmesh-users] Material number and other tags.

Hi guys,

I am in a pickle here. I originally had my custom implementation of
associating tags with elements and nodes to maintain the material
numbers and other physics relevant information. But then, I modified
my code to actually attach the material number information to the
sbd_id in Elem. I remember reading that most of you follow this to
identify the material corresponding to a finite element.

I have a complication due to this: I have more than 255 materials and
since _sbd_id is unsigned char, this leads to garbage. On the other
hand, I do not want to go back to mesh_data usage either since it is
messy and I need to propagate information based on refinement and
coarsening.

As a solution, I was wondering whether it would make sense to add a
std::vector<objects> for every element and node. Of course, by default
these will be empty to save resources. This way, the user controls
what tags to associate with every element and thereby helps the
physics calculations in a better way.

If you think this is not the way to go and then do pass on your
comments. If you have better ideas that you are using already or want
to try out, I would love to hear that too.

Thanks in advance.
Vijay

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